From 65bb2e0fc5a67200db95911207ef9662aaf7ab9d Mon Sep 17 00:00:00 2001 From: Xu Wang Date: Tue, 18 Aug 2020 07:16:11 +0000 Subject: libbpf: Convert comma to semicolon Replace a comma between expression statements by a semicolon. Signed-off-by: Xu Wang Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200818071611.21923-1-vulab@iscas.ac.cn --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5d20b2da4427..5055e1531e43 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -8594,7 +8594,7 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt, struct perf_buffer_params p = {}; struct perf_event_attr attr = { 0, }; - attr.config = PERF_COUNT_SW_BPF_OUTPUT, + attr.config = PERF_COUNT_SW_BPF_OUTPUT; attr.type = PERF_TYPE_SOFTWARE; attr.sample_type = PERF_SAMPLE_RAW; attr.sample_period = 1; -- cgit v1.2.3 From 8d708236058601f1b08b0ca2a1cd9fff28034416 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 14:33:50 -0700 Subject: libbpf: Disable -Wswitch-enum compiler warning That compilation warning is more annoying, than helpful. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818213356.2629020-2-andriin@fb.com --- tools/lib/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index bf8ed134cb8a..95c946e94ca5 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -107,7 +107,7 @@ ifeq ($(feature-reallocarray), 0) endif # Append required CFLAGS -override CFLAGS += $(EXTRA_WARNINGS) +override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum override CFLAGS += -Werror -Wall override CFLAGS += -fPIC override CFLAGS += $(INCLUDES) -- cgit v1.2.3 From 47b6cb4d0add454859f386337e6079e01ac7db8f Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 14:33:51 -0700 Subject: libbpf: Make kernel feature probing lazy Turn libbpf's kernel feature probing into lazily-performed checks. This allows to skip performing unnecessary feature checks, if a given BPF application doesn't rely on a particular kernel feature. As we grow number of feature probes, libbpf might perform less unnecessary syscalls and scale better with number of feature probes long-term. By decoupling feature checks from bpf_object, it's also possible to perform feature probing from libbpf static helpers and low-level APIs, if necessary. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818213356.2629020-3-andriin@fb.com --- tools/lib/bpf/libbpf.c | 150 ++++++++++++++++++++++++++++--------------------- 1 file changed, 86 insertions(+), 64 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5055e1531e43..2ee168822d33 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -165,23 +165,26 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } -struct bpf_capabilities { +enum kern_feature_id { /* v4.14: kernel support for program & map names. */ - __u32 name:1; + FEAT_PROG_NAME, /* v5.2: kernel support for global data sections. */ - __u32 global_data:1; + FEAT_GLOBAL_DATA, /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ - __u32 btf_func:1; + FEAT_BTF_FUNC, /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ - __u32 btf_datasec:1; - /* BPF_F_MMAPABLE is supported for arrays */ - __u32 array_mmap:1; + FEAT_BTF_DATASEC, /* BTF_FUNC_GLOBAL is supported */ - __u32 btf_func_global:1; + FEAT_BTF_GLOBAL_FUNC, + /* BPF_F_MMAPABLE is supported for arrays */ + FEAT_ARRAY_MMAP, /* kernel support for expected_attach_type in BPF_PROG_LOAD */ - __u32 exp_attach_type:1; + FEAT_EXP_ATTACH_TYPE, + __FEAT_CNT, }; +static bool kernel_supports(enum kern_feature_id feat_id); + enum reloc_type { RELO_LD64, RELO_CALL, @@ -253,8 +256,6 @@ struct bpf_program { __u32 func_info_rec_size; __u32 func_info_cnt; - struct bpf_capabilities *caps; - void *line_info; __u32 line_info_rec_size; __u32 line_info_cnt; @@ -436,8 +437,6 @@ struct bpf_object { void *priv; bpf_object_clear_priv_t clear_priv; - struct bpf_capabilities caps; - char path[]; }; #define obj_elf_valid(o) ((o)->efile.elf) @@ -561,7 +560,6 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, if (err) return err; - prog.caps = &obj->caps; progs = obj->programs; nr_progs = obj->nr_programs; @@ -2340,18 +2338,18 @@ static bool section_have_execinstr(struct bpf_object *obj, int idx) static bool btf_needs_sanitization(struct bpf_object *obj) { - bool has_func_global = obj->caps.btf_func_global; - bool has_datasec = obj->caps.btf_datasec; - bool has_func = obj->caps.btf_func; + bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); + bool has_func = kernel_supports(FEAT_BTF_FUNC); return !has_func || !has_datasec || !has_func_global; } static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) { - bool has_func_global = obj->caps.btf_func_global; - bool has_datasec = obj->caps.btf_datasec; - bool has_func = obj->caps.btf_func; + bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); + bool has_func = kernel_supports(FEAT_BTF_FUNC); struct btf_type *t; int i, j, vlen; @@ -3433,8 +3431,7 @@ bpf_object__probe_loading(struct bpf_object *obj) return 0; } -static int -bpf_object__probe_name(struct bpf_object *obj) +static int probe_kern_prog_name(void) { struct bpf_load_program_attr attr; struct bpf_insn insns[] = { @@ -3453,15 +3450,14 @@ bpf_object__probe_name(struct bpf_object *obj) attr.name = "test"; ret = bpf_load_program_xattr(&attr, NULL, 0); if (ret >= 0) { - obj->caps.name = 1; close(ret); + return 1; } return 0; } -static int -bpf_object__probe_global_data(struct bpf_object *obj) +static int probe_kern_global_data(void) { struct bpf_load_program_attr prg_attr; struct bpf_create_map_attr map_attr; @@ -3498,16 +3494,16 @@ bpf_object__probe_global_data(struct bpf_object *obj) prg_attr.license = "GPL"; ret = bpf_load_program_xattr(&prg_attr, NULL, 0); + close(map); if (ret >= 0) { - obj->caps.global_data = 1; close(ret); + return 1; } - close(map); return 0; } -static int bpf_object__probe_btf_func(struct bpf_object *obj) +static int probe_kern_btf_func(void) { static const char strs[] = "\0int\0x\0a"; /* void x(int a) {} */ @@ -3525,7 +3521,6 @@ static int bpf_object__probe_btf_func(struct bpf_object *obj) btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs)); if (btf_fd >= 0) { - obj->caps.btf_func = 1; close(btf_fd); return 1; } @@ -3533,7 +3528,7 @@ static int bpf_object__probe_btf_func(struct bpf_object *obj) return 0; } -static int bpf_object__probe_btf_func_global(struct bpf_object *obj) +static int probe_kern_btf_func_global(void) { static const char strs[] = "\0int\0x\0a"; /* static void x(int a) {} */ @@ -3551,7 +3546,6 @@ static int bpf_object__probe_btf_func_global(struct bpf_object *obj) btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs)); if (btf_fd >= 0) { - obj->caps.btf_func_global = 1; close(btf_fd); return 1; } @@ -3559,7 +3553,7 @@ static int bpf_object__probe_btf_func_global(struct bpf_object *obj) return 0; } -static int bpf_object__probe_btf_datasec(struct bpf_object *obj) +static int probe_kern_btf_datasec(void) { static const char strs[] = "\0x\0.data"; /* static int a; */ @@ -3578,7 +3572,6 @@ static int bpf_object__probe_btf_datasec(struct bpf_object *obj) btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs)); if (btf_fd >= 0) { - obj->caps.btf_datasec = 1; close(btf_fd); return 1; } @@ -3586,7 +3579,7 @@ static int bpf_object__probe_btf_datasec(struct bpf_object *obj) return 0; } -static int bpf_object__probe_array_mmap(struct bpf_object *obj) +static int probe_kern_array_mmap(void) { struct bpf_create_map_attr attr = { .map_type = BPF_MAP_TYPE_ARRAY, @@ -3599,16 +3592,13 @@ static int bpf_object__probe_array_mmap(struct bpf_object *obj) fd = bpf_create_map_xattr(&attr); if (fd >= 0) { - obj->caps.array_mmap = 1; close(fd); return 1; } - return 0; } -static int -bpf_object__probe_exp_attach_type(struct bpf_object *obj) +static int probe_kern_exp_attach_type(void) { struct bpf_load_program_attr attr; struct bpf_insn insns[] = { @@ -3631,34 +3621,67 @@ bpf_object__probe_exp_attach_type(struct bpf_object *obj) fd = bpf_load_program_xattr(&attr, NULL, 0); if (fd >= 0) { - obj->caps.exp_attach_type = 1; close(fd); return 1; } return 0; } -static int -bpf_object__probe_caps(struct bpf_object *obj) -{ - int (*probe_fn[])(struct bpf_object *obj) = { - bpf_object__probe_name, - bpf_object__probe_global_data, - bpf_object__probe_btf_func, - bpf_object__probe_btf_func_global, - bpf_object__probe_btf_datasec, - bpf_object__probe_array_mmap, - bpf_object__probe_exp_attach_type, - }; - int i, ret; +enum kern_feature_result { + FEAT_UNKNOWN = 0, + FEAT_SUPPORTED = 1, + FEAT_MISSING = 2, +}; - for (i = 0; i < ARRAY_SIZE(probe_fn); i++) { - ret = probe_fn[i](obj); - if (ret < 0) - pr_debug("Probe #%d failed with %d.\n", i, ret); +typedef int (*feature_probe_fn)(void); + +static struct kern_feature_desc { + const char *desc; + feature_probe_fn probe; + enum kern_feature_result res; +} feature_probes[__FEAT_CNT] = { + [FEAT_PROG_NAME] = { + "BPF program name", probe_kern_prog_name, + }, + [FEAT_GLOBAL_DATA] = { + "global variables", probe_kern_global_data, + }, + [FEAT_BTF_FUNC] = { + "BTF functions", probe_kern_btf_func, + }, + [FEAT_BTF_GLOBAL_FUNC] = { + "BTF global function", probe_kern_btf_func_global, + }, + [FEAT_BTF_DATASEC] = { + "BTF data section and variable", probe_kern_btf_datasec, + }, + [FEAT_ARRAY_MMAP] = { + "ARRAY map mmap()", probe_kern_array_mmap, + }, + [FEAT_EXP_ATTACH_TYPE] = { + "BPF_PROG_LOAD expected_attach_type attribute", + probe_kern_exp_attach_type, + }, +}; + +static bool kernel_supports(enum kern_feature_id feat_id) +{ + struct kern_feature_desc *feat = &feature_probes[feat_id]; + int ret; + + if (READ_ONCE(feat->res) == FEAT_UNKNOWN) { + ret = feat->probe(); + if (ret > 0) { + WRITE_ONCE(feat->res, FEAT_SUPPORTED); + } else if (ret == 0) { + WRITE_ONCE(feat->res, FEAT_MISSING); + } else { + pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret); + WRITE_ONCE(feat->res, FEAT_MISSING); + } } - return 0; + return READ_ONCE(feat->res) == FEAT_SUPPORTED; } static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) @@ -3760,7 +3783,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) memset(&create_attr, 0, sizeof(create_attr)); - if (obj->caps.name) + if (kernel_supports(FEAT_PROG_NAME)) create_attr.name = map->name; create_attr.map_ifindex = map->map_ifindex; create_attr.map_type = def->type; @@ -5364,12 +5387,12 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); load_attr.prog_type = prog->type; /* old kernels might not support specifying expected_attach_type */ - if (!prog->caps->exp_attach_type && prog->sec_def && + if (!kernel_supports(FEAT_EXP_ATTACH_TYPE) && prog->sec_def && prog->sec_def->is_exp_attach_type_optional) load_attr.expected_attach_type = 0; else load_attr.expected_attach_type = prog->expected_attach_type; - if (prog->caps->name) + if (kernel_supports(FEAT_PROG_NAME)) load_attr.name = prog->name; load_attr.insns = insns; load_attr.insns_cnt = insns_cnt; @@ -5387,7 +5410,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, } /* specify func_info/line_info only if kernel supports them */ btf_fd = bpf_object__btf_fd(prog->obj); - if (btf_fd >= 0 && prog->obj->caps.btf_func) { + if (btf_fd >= 0 && kernel_supports(FEAT_BTF_FUNC)) { load_attr.prog_btf_fd = btf_fd; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; @@ -5750,11 +5773,11 @@ static int bpf_object__sanitize_maps(struct bpf_object *obj) bpf_object__for_each_map(m, obj) { if (!bpf_map__is_internal(m)) continue; - if (!obj->caps.global_data) { + if (!kernel_supports(FEAT_GLOBAL_DATA)) { pr_warn("kernel doesn't support global data\n"); return -ENOTSUP; } - if (!obj->caps.array_mmap) + if (!kernel_supports(FEAT_ARRAY_MMAP)) m->def.map_flags ^= BPF_F_MMAPABLE; } @@ -5904,7 +5927,6 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr) } err = bpf_object__probe_loading(obj); - err = err ? : bpf_object__probe_caps(obj); err = err ? : bpf_object__resolve_externs(obj, obj->kconfig); err = err ? : bpf_object__sanitize_and_load_btf(obj); err = err ? : bpf_object__sanitize_maps(obj); -- cgit v1.2.3 From bb180fb2401dfed0ba85699064e60d62af351ff9 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 14:33:52 -0700 Subject: libbpf: Factor out common logic of testing and closing FD Factor out common piece of logic that detects support for a feature based on successfully created FD. Also take care of closing FD, if it was created. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818213356.2629020-4-andriin@fb.com --- tools/lib/bpf/libbpf.c | 70 ++++++++++++-------------------------------------- 1 file changed, 17 insertions(+), 53 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2ee168822d33..08875ab9fe35 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3431,6 +3431,13 @@ bpf_object__probe_loading(struct bpf_object *obj) return 0; } +static int probe_fd(int fd) +{ + if (fd >= 0) + close(fd); + return fd >= 0; +} + static int probe_kern_prog_name(void) { struct bpf_load_program_attr attr; @@ -3449,12 +3456,7 @@ static int probe_kern_prog_name(void) attr.license = "GPL"; attr.name = "test"; ret = bpf_load_program_xattr(&attr, NULL, 0); - if (ret >= 0) { - close(ret); - return 1; - } - - return 0; + return probe_fd(ret); } static int probe_kern_global_data(void) @@ -3495,12 +3497,7 @@ static int probe_kern_global_data(void) ret = bpf_load_program_xattr(&prg_attr, NULL, 0); close(map); - if (ret >= 0) { - close(ret); - return 1; - } - - return 0; + return probe_fd(ret); } static int probe_kern_btf_func(void) @@ -3516,16 +3513,9 @@ static int probe_kern_btf_func(void) /* FUNC x */ /* [3] */ BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2), }; - int btf_fd; - btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs)); - if (btf_fd >= 0) { - close(btf_fd); - return 1; - } - - return 0; + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); } static int probe_kern_btf_func_global(void) @@ -3541,16 +3531,9 @@ static int probe_kern_btf_func_global(void) /* FUNC x BTF_FUNC_GLOBAL */ /* [3] */ BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2), }; - int btf_fd; - btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs)); - if (btf_fd >= 0) { - close(btf_fd); - return 1; - } - - return 0; + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); } static int probe_kern_btf_datasec(void) @@ -3567,16 +3550,9 @@ static int probe_kern_btf_datasec(void) BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4), BTF_VAR_SECINFO_ENC(2, 0, 4), }; - int btf_fd; - btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), - strs, sizeof(strs)); - if (btf_fd >= 0) { - close(btf_fd); - return 1; - } - - return 0; + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); } static int probe_kern_array_mmap(void) @@ -3588,14 +3564,8 @@ static int probe_kern_array_mmap(void) .value_size = sizeof(int), .max_entries = 1, }; - int fd; - fd = bpf_create_map_xattr(&attr); - if (fd >= 0) { - close(fd); - return 1; - } - return 0; + return probe_fd(bpf_create_map_xattr(&attr)); } static int probe_kern_exp_attach_type(void) @@ -3605,7 +3575,6 @@ static int probe_kern_exp_attach_type(void) BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; - int fd; memset(&attr, 0, sizeof(attr)); /* use any valid combination of program type and (optional) @@ -3619,12 +3588,7 @@ static int probe_kern_exp_attach_type(void) attr.insns_cnt = ARRAY_SIZE(insns); attr.license = "GPL"; - fd = bpf_load_program_xattr(&attr, NULL, 0); - if (fd >= 0) { - close(fd); - return 1; - } - return 0; + return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); } enum kern_feature_result { -- cgit v1.2.3 From 109cea5a594f921632ca599b385aaa0575971045 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 14:33:53 -0700 Subject: libbpf: Sanitize BPF program code for bpf_probe_read_{kernel, user}[_str] Add BPF program code sanitization pass, replacing calls to BPF bpf_probe_read_{kernel,user}[_str]() helpers with bpf_probe_read[_str](), if libbpf detects that kernel doesn't support new variants. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818213356.2629020-5-andriin@fb.com --- tools/lib/bpf/libbpf.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 08875ab9fe35..e3ab1794d2c3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -180,6 +180,8 @@ enum kern_feature_id { FEAT_ARRAY_MMAP, /* kernel support for expected_attach_type in BPF_PROG_LOAD */ FEAT_EXP_ATTACH_TYPE, + /* bpf_probe_read_{kernel,user}[_str] helpers */ + FEAT_PROBE_READ_KERN, __FEAT_CNT, }; @@ -3591,6 +3593,27 @@ static int probe_kern_exp_attach_type(void) return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); } +static int probe_kern_probe_read_kernel(void) +{ + struct bpf_load_program_attr attr; + struct bpf_insn insns[] = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */ + BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */ + BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel), + BPF_EXIT_INSN(), + }; + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = BPF_PROG_TYPE_KPROBE; + attr.insns = insns; + attr.insns_cnt = ARRAY_SIZE(insns); + attr.license = "GPL"; + + return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); +} + enum kern_feature_result { FEAT_UNKNOWN = 0, FEAT_SUPPORTED = 1, @@ -3626,6 +3649,9 @@ static struct kern_feature_desc { "BPF_PROG_LOAD expected_attach_type attribute", probe_kern_exp_attach_type, }, + [FEAT_PROBE_READ_KERN] = { + "bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel, + } }; static bool kernel_supports(enum kern_feature_id feat_id) @@ -5335,6 +5361,53 @@ static int bpf_object__collect_reloc(struct bpf_object *obj) return 0; } +static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id) +{ + __u8 class = BPF_CLASS(insn->code); + + if ((class == BPF_JMP || class == BPF_JMP32) && + BPF_OP(insn->code) == BPF_CALL && + BPF_SRC(insn->code) == BPF_K && + insn->src_reg == 0 && insn->dst_reg == 0) { + if (func_id) + *func_id = insn->imm; + return true; + } + return false; +} + +static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program *prog) +{ + struct bpf_insn *insn = prog->insns; + enum bpf_func_id func_id; + int i; + + for (i = 0; i < prog->insns_cnt; i++, insn++) { + if (!insn_is_helper_call(insn, &func_id)) + continue; + + /* on kernels that don't yet support + * bpf_probe_read_{kernel,user}[_str] helpers, fall back + * to bpf_probe_read() which works well for old kernels + */ + switch (func_id) { + case BPF_FUNC_probe_read_kernel: + case BPF_FUNC_probe_read_user: + if (!kernel_supports(FEAT_PROBE_READ_KERN)) + insn->imm = BPF_FUNC_probe_read; + break; + case BPF_FUNC_probe_read_kernel_str: + case BPF_FUNC_probe_read_user_str: + if (!kernel_supports(FEAT_PROBE_READ_KERN)) + insn->imm = BPF_FUNC_probe_read_str; + break; + default: + break; + } + } + return 0; +} + static int load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, char *license, __u32 kern_version, int *pfd) @@ -5549,6 +5622,13 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level) size_t i; int err; + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + err = bpf_object__sanitize_prog(obj, prog); + if (err) + return err; + } + for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; if (bpf_program__is_function_storage(prog, obj)) -- cgit v1.2.3 From 70785cfb19287b4b075a266887be5e024bf1206a Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 14:33:55 -0700 Subject: libbpf: Switch tracing and CO-RE helper macros to bpf_probe_read_kernel() Now that libbpf can automatically fallback to bpf_probe_read() on old kernels not yet supporting bpf_probe_read_kernel(), switch libbpf BPF-side helper macros to use appropriate BPF helper for reading kernel data. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Cc: Ilya Leoshkevich Link: https://lore.kernel.org/bpf/20200818213356.2629020-7-andriin@fb.com --- tools/lib/bpf/bpf_core_read.h | 40 ++++++++++++++++++++++------------------ tools/lib/bpf/bpf_tracing.h | 4 ++-- 2 files changed, 24 insertions(+), 20 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index eae5cccff761..03152cb143b7 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -24,27 +24,29 @@ enum bpf_field_info_kind { #if __BYTE_ORDER == __LITTLE_ENDIAN #define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ - bpf_probe_read((void *)dst, \ - __CORE_RELO(src, fld, BYTE_SIZE), \ - (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) + bpf_probe_read_kernel( \ + (void *)dst, \ + __CORE_RELO(src, fld, BYTE_SIZE), \ + (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) #else /* semantics of LSHIFT_64 assumes loading values into low-ordered bytes, so * for big-endian we need to adjust destination pointer accordingly, based on * field byte size */ #define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ - bpf_probe_read((void *)dst + (8 - __CORE_RELO(src, fld, BYTE_SIZE)), \ - __CORE_RELO(src, fld, BYTE_SIZE), \ - (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) + bpf_probe_read_kernel( \ + (void *)dst + (8 - __CORE_RELO(src, fld, BYTE_SIZE)), \ + __CORE_RELO(src, fld, BYTE_SIZE), \ + (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) #endif /* * Extract bitfield, identified by s->field, and return its value as u64. * All this is done in relocatable manner, so bitfield changes such as * signedness, bit size, offset changes, this will be handled automatically. - * This version of macro is using bpf_probe_read() to read underlying integer - * storage. Macro functions as an expression and its return type is - * bpf_probe_read()'s return value: 0, on success, <0 on error. + * This version of macro is using bpf_probe_read_kernel() to read underlying + * integer storage. Macro functions as an expression and its return type is + * bpf_probe_read_kernel()'s return value: 0, on success, <0 on error. */ #define BPF_CORE_READ_BITFIELD_PROBED(s, field) ({ \ unsigned long long val = 0; \ @@ -99,8 +101,8 @@ enum bpf_field_info_kind { __builtin_preserve_field_info(field, BPF_FIELD_BYTE_SIZE) /* - * bpf_core_read() abstracts away bpf_probe_read() call and captures offset - * relocation for source address using __builtin_preserve_access_index() + * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures + * offset relocation for source address using __builtin_preserve_access_index() * built-in, provided by Clang. * * __builtin_preserve_access_index() takes as an argument an expression of @@ -115,8 +117,8 @@ enum bpf_field_info_kind { * (local) BTF, used to record relocation. */ #define bpf_core_read(dst, sz, src) \ - bpf_probe_read(dst, sz, \ - (const void *)__builtin_preserve_access_index(src)) + bpf_probe_read_kernel(dst, sz, \ + (const void *)__builtin_preserve_access_index(src)) /* * bpf_core_read_str() is a thin wrapper around bpf_probe_read_str() @@ -124,8 +126,8 @@ enum bpf_field_info_kind { * argument. */ #define bpf_core_read_str(dst, sz, src) \ - bpf_probe_read_str(dst, sz, \ - (const void *)__builtin_preserve_access_index(src)) + bpf_probe_read_kernel_str(dst, sz, \ + (const void *)__builtin_preserve_access_index(src)) #define ___concat(a, b) a ## b #define ___apply(fn, n) ___concat(fn, n) @@ -239,15 +241,17 @@ enum bpf_field_info_kind { * int x = BPF_CORE_READ(s, a.b.c, d.e, f, g); * * BPF_CORE_READ will decompose above statement into 4 bpf_core_read (BPF - * CO-RE relocatable bpf_probe_read() wrapper) calls, logically equivalent to: + * CO-RE relocatable bpf_probe_read_kernel() wrapper) calls, logically + * equivalent to: * 1. const void *__t = s->a.b.c; * 2. __t = __t->d.e; * 3. __t = __t->f; * 4. return __t->g; * * Equivalence is logical, because there is a heavy type casting/preservation - * involved, as well as all the reads are happening through bpf_probe_read() - * calls using __builtin_preserve_access_index() to emit CO-RE relocations. + * involved, as well as all the reads are happening through + * bpf_probe_read_kernel() calls using __builtin_preserve_access_index() to + * emit CO-RE relocations. * * N.B. Only up to 9 "field accessors" are supported, which should be more * than enough for any practical purpose. diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index eebf020cbe3e..f9ef37707888 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -289,9 +289,9 @@ struct pt_regs; #define BPF_KRETPROBE_READ_RET_IP BPF_KPROBE_READ_RET_IP #else #define BPF_KPROBE_READ_RET_IP(ip, ctx) \ - ({ bpf_probe_read(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)); }) + ({ bpf_probe_read_kernel(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)); }) #define BPF_KRETPROBE_READ_RET_IP(ip, ctx) \ - ({ bpf_probe_read(&(ip), sizeof(ip), \ + ({ bpf_probe_read_kernel(&(ip), sizeof(ip), \ (void *)(PT_REGS_FP(ctx) + sizeof(ip))); }) #endif -- cgit v1.2.3 From 68b08647c7d56ea15114435c3023adc017d11b81 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 14:33:56 -0700 Subject: libbpf: Detect minimal BTF support and skip BTF loading, if missing Detect whether a kernel supports any BTF at all, and if not, don't even attempt loading BTF to avoid unnecessary log messages like: libbpf: Error loading BTF: Invalid argument(22) libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818213356.2629020-8-andriin@fb.com --- tools/lib/bpf/libbpf.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e3ab1794d2c3..775fa6317483 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -170,6 +170,8 @@ enum kern_feature_id { FEAT_PROG_NAME, /* v5.2: kernel support for global data sections. */ FEAT_GLOBAL_DATA, + /* BTF support */ + FEAT_BTF, /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ FEAT_BTF_FUNC, /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ @@ -2533,6 +2535,15 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) if (!obj->btf) return 0; + if (!kernel_supports(FEAT_BTF)) { + if (kernel_needs_btf(obj)) { + err = -EOPNOTSUPP; + goto report; + } + pr_debug("Kernel doesn't support BTF, skipping uploading it.\n"); + return 0; + } + sanitize = btf_needs_sanitization(obj); if (sanitize) { const void *raw_data; @@ -2558,6 +2569,7 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) } btf__free(kern_btf); } +report: if (err) { btf_mandatory = kernel_needs_btf(obj); pr_warn("Error loading .BTF into kernel: %d. %s\n", err, @@ -3502,6 +3514,18 @@ static int probe_kern_global_data(void) return probe_fd(ret); } +static int probe_kern_btf(void) +{ + static const char strs[] = "\0int"; + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + static int probe_kern_btf_func(void) { static const char strs[] = "\0int\0x\0a"; @@ -3633,6 +3657,9 @@ static struct kern_feature_desc { [FEAT_GLOBAL_DATA] = { "global variables", probe_kern_global_data, }, + [FEAT_BTF] = { + "minimal BTF", probe_kern_btf, + }, [FEAT_BTF_FUNC] = { "BTF functions", probe_kern_btf_func, }, -- cgit v1.2.3 From 81ba0889027505b7d5136319117e473a69a923c4 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 15:39:13 -0700 Subject: libbpf: Improve error logging for mismatched BTF kind cases Instead of printing out integer value of BTF kind, print out a string representation of a kind. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818223921.2911963-2-andriin@fb.com --- tools/lib/bpf/libbpf.c | 59 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 41 insertions(+), 18 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 775fa6317483..94d92763bcb1 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1886,6 +1886,29 @@ resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id) return btf_is_func_proto(t) ? t : NULL; } +static const char *btf_kind_str(const struct btf_type *t) +{ + switch (btf_kind(t)) { + case BTF_KIND_UNKN: return "void"; + case BTF_KIND_INT: return "int"; + case BTF_KIND_PTR: return "ptr"; + case BTF_KIND_ARRAY: return "array"; + case BTF_KIND_STRUCT: return "struct"; + case BTF_KIND_UNION: return "union"; + case BTF_KIND_ENUM: return "enum"; + case BTF_KIND_FWD: return "fwd"; + case BTF_KIND_TYPEDEF: return "typedef"; + case BTF_KIND_VOLATILE: return "volatile"; + case BTF_KIND_CONST: return "const"; + case BTF_KIND_RESTRICT: return "restrict"; + case BTF_KIND_FUNC: return "func"; + case BTF_KIND_FUNC_PROTO: return "func_proto"; + case BTF_KIND_VAR: return "var"; + case BTF_KIND_DATASEC: return "datasec"; + default: return "unknown"; + } +} + /* * Fetch integer attribute of BTF map definition. Such attributes are * represented using a pointer to an array, in which dimensionality of array @@ -1902,8 +1925,8 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, const struct btf_type *arr_t; if (!btf_is_ptr(t)) { - pr_warn("map '%s': attr '%s': expected PTR, got %u.\n", - map_name, name, btf_kind(t)); + pr_warn("map '%s': attr '%s': expected PTR, got %s.\n", + map_name, name, btf_kind_str(t)); return false; } @@ -1914,8 +1937,8 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, return false; } if (!btf_is_array(arr_t)) { - pr_warn("map '%s': attr '%s': expected ARRAY, got %u.\n", - map_name, name, btf_kind(arr_t)); + pr_warn("map '%s': attr '%s': expected ARRAY, got %s.\n", + map_name, name, btf_kind_str(arr_t)); return false; } arr_info = btf_array(arr_t); @@ -2009,8 +2032,8 @@ static int parse_btf_map_def(struct bpf_object *obj, return -EINVAL; } if (!btf_is_ptr(t)) { - pr_warn("map '%s': key spec is not PTR: %u.\n", - map->name, btf_kind(t)); + pr_warn("map '%s': key spec is not PTR: %s.\n", + map->name, btf_kind_str(t)); return -EINVAL; } sz = btf__resolve_size(obj->btf, t->type); @@ -2051,8 +2074,8 @@ static int parse_btf_map_def(struct bpf_object *obj, return -EINVAL; } if (!btf_is_ptr(t)) { - pr_warn("map '%s': value spec is not PTR: %u.\n", - map->name, btf_kind(t)); + pr_warn("map '%s': value spec is not PTR: %s.\n", + map->name, btf_kind_str(t)); return -EINVAL; } sz = btf__resolve_size(obj->btf, t->type); @@ -2109,14 +2132,14 @@ static int parse_btf_map_def(struct bpf_object *obj, t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, NULL); if (!btf_is_ptr(t)) { - pr_warn("map '%s': map-in-map inner def is of unexpected kind %u.\n", - map->name, btf_kind(t)); + pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", + map->name, btf_kind_str(t)); return -EINVAL; } t = skip_mods_and_typedefs(obj->btf, t->type, NULL); if (!btf_is_struct(t)) { - pr_warn("map '%s': map-in-map inner def is of unexpected kind %u.\n", - map->name, btf_kind(t)); + pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", + map->name, btf_kind_str(t)); return -EINVAL; } @@ -2207,8 +2230,8 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, return -EINVAL; } if (!btf_is_var(var)) { - pr_warn("map '%s': unexpected var kind %u.\n", - map_name, btf_kind(var)); + pr_warn("map '%s': unexpected var kind %s.\n", + map_name, btf_kind_str(var)); return -EINVAL; } if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED && @@ -2220,8 +2243,8 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, def = skip_mods_and_typedefs(obj->btf, var->type, NULL); if (!btf_is_struct(def)) { - pr_warn("map '%s': unexpected def kind %u.\n", - map_name, btf_kind(var)); + pr_warn("map '%s': unexpected def kind %s.\n", + map_name, btf_kind_str(var)); return -EINVAL; } if (def->size > vi->size) { @@ -4212,8 +4235,8 @@ static int bpf_core_spec_parse(const struct btf *btf, return sz; spec->bit_offset += access_idx * sz * 8; } else { - pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n", - type_id, spec_str, i, id, btf_kind(t)); + pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %s\n", + type_id, spec_str, i, id, btf_kind_str(t)); return -EINVAL; } } -- cgit v1.2.3 From 28b93c64499ae09d9dc8c04123b15f8654a93c4c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 15:39:14 -0700 Subject: libbpf: Clean up and improve CO-RE reloc logging Add logging of local/target type kind (struct/union/typedef/etc). Preserve unresolved root type ID (for cases of typedef). Improve the format of CO-RE reloc spec output format to contain only relevant and succinct info. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818223921.2911963-3-andriin@fb.com --- tools/lib/bpf/btf.c | 17 ++--- tools/lib/bpf/btf.h | 38 --------- tools/lib/bpf/libbpf.c | 165 +++++++++++++++++++++++++--------------- tools/lib/bpf/libbpf_internal.h | 78 ++++++++++++++----- 4 files changed, 169 insertions(+), 129 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7dfca7016aaa..1deedbd19c6c 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1131,14 +1131,14 @@ static int btf_ext_setup_line_info(struct btf_ext *btf_ext) return btf_ext_setup_info(btf_ext, ¶m); } -static int btf_ext_setup_field_reloc(struct btf_ext *btf_ext) +static int btf_ext_setup_core_relos(struct btf_ext *btf_ext) { struct btf_ext_sec_setup_param param = { - .off = btf_ext->hdr->field_reloc_off, - .len = btf_ext->hdr->field_reloc_len, - .min_rec_size = sizeof(struct bpf_field_reloc), - .ext_info = &btf_ext->field_reloc_info, - .desc = "field_reloc", + .off = btf_ext->hdr->core_relo_off, + .len = btf_ext->hdr->core_relo_len, + .min_rec_size = sizeof(struct bpf_core_relo), + .ext_info = &btf_ext->core_relo_info, + .desc = "core_relo", }; return btf_ext_setup_info(btf_ext, ¶m); @@ -1217,10 +1217,9 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) if (err) goto done; - if (btf_ext->hdr->hdr_len < - offsetofend(struct btf_ext_header, field_reloc_len)) + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) goto done; - err = btf_ext_setup_field_reloc(btf_ext); + err = btf_ext_setup_core_relos(btf_ext); if (err) goto done; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 1ca14448df4c..91f0ad0e0325 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -24,44 +24,6 @@ struct btf_type; struct bpf_object; -/* - * The .BTF.ext ELF section layout defined as - * struct btf_ext_header - * func_info subsection - * - * The func_info subsection layout: - * record size for struct bpf_func_info in the func_info subsection - * struct btf_sec_func_info for section #1 - * a list of bpf_func_info records for section #1 - * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h - * but may not be identical - * struct btf_sec_func_info for section #2 - * a list of bpf_func_info records for section #2 - * ...... - * - * Note that the bpf_func_info record size in .BTF.ext may not - * be the same as the one defined in include/uapi/linux/bpf.h. - * The loader should ensure that record_size meets minimum - * requirement and pass the record as is to the kernel. The - * kernel will handle the func_info properly based on its contents. - */ -struct btf_ext_header { - __u16 magic; - __u8 version; - __u8 flags; - __u32 hdr_len; - - /* All offsets are in bytes relative to the end of this header */ - __u32 func_info_off; - __u32 func_info_len; - __u32 line_info_off; - __u32 line_info_len; - - /* optional part of .BTF.ext header */ - __u32 field_reloc_off; - __u32 field_reloc_len; -}; - LIBBPF_API void btf__free(struct btf *btf); LIBBPF_API struct btf *btf__new(const void *data, __u32 size); LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 94d92763bcb1..894d388094e3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2524,7 +2524,7 @@ static int bpf_object__load_vmlinux_btf(struct bpf_object *obj) int err; /* CO-RE relocations need kernel BTF */ - if (obj->btf_ext && obj->btf_ext->field_reloc_info.len) + if (obj->btf_ext && obj->btf_ext->core_relo_info.len) need_vmlinux_btf = true; bpf_object__for_each_program(prog, obj) { @@ -4074,6 +4074,10 @@ struct bpf_core_spec { const struct btf *btf; /* high-level spec: named fields and array indices only */ struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN]; + /* original unresolved (no skip_mods_or_typedefs) root type ID */ + __u32 root_type_id; + /* CO-RE relocation kind */ + enum bpf_core_relo_kind relo_kind; /* high-level spec length */ int len; /* raw, low-level spec: 1-to-1 with accessor spec string */ @@ -4104,8 +4108,36 @@ static bool is_flex_arr(const struct btf *btf, return acc->idx == btf_vlen(t) - 1; } +static const char *core_relo_kind_str(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_FIELD_BYTE_OFFSET: return "byte_off"; + case BPF_FIELD_BYTE_SIZE: return "byte_sz"; + case BPF_FIELD_EXISTS: return "field_exists"; + case BPF_FIELD_SIGNED: return "signed"; + case BPF_FIELD_LSHIFT_U64: return "lshift_u64"; + case BPF_FIELD_RSHIFT_U64: return "rshift_u64"; + default: return "unknown"; + } +} + +static bool core_relo_is_field_based(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_FIELD_BYTE_OFFSET: + case BPF_FIELD_BYTE_SIZE: + case BPF_FIELD_EXISTS: + case BPF_FIELD_SIGNED: + case BPF_FIELD_LSHIFT_U64: + case BPF_FIELD_RSHIFT_U64: + return true; + default: + return false; + } +} + /* - * Turn bpf_field_reloc into a low- and high-level spec representation, + * Turn bpf_core_relo into a low- and high-level spec representation, * validating correctness along the way, as well as calculating resulting * field bit offset, specified by accessor string. Low-level spec captures * every single level of nestedness, including traversing anonymous @@ -4135,9 +4167,10 @@ static bool is_flex_arr(const struct btf *btf, * - array element #3 access (corresponds to '3' in low-level spec). * */ -static int bpf_core_spec_parse(const struct btf *btf, +static int bpf_core_parse_spec(const struct btf *btf, __u32 type_id, const char *spec_str, + enum bpf_core_relo_kind relo_kind, struct bpf_core_spec *spec) { int access_idx, parsed_len, i; @@ -4152,6 +4185,8 @@ static int bpf_core_spec_parse(const struct btf *btf, memset(spec, 0, sizeof(*spec)); spec->btf = btf; + spec->root_type_id = type_id; + spec->relo_kind = relo_kind; /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */ while (*spec_str) { @@ -4178,6 +4213,9 @@ static int bpf_core_spec_parse(const struct btf *btf, spec->spec[0].idx = access_idx; spec->len++; + if (!core_relo_is_field_based(relo_kind)) + return -EINVAL; + sz = btf__resolve_size(btf, id); if (sz < 0) return sz; @@ -4285,17 +4323,17 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, const struct btf *targ_btf) { size_t local_essent_len, targ_essent_len; - const char *local_name, *targ_name; - const struct btf_type *t; + const char *local_name, *targ_name, *targ_kind; + const struct btf_type *t, *local_t; struct ids_vec *cand_ids; __u32 *new_ids; int i, err, n; - t = btf__type_by_id(local_btf, local_type_id); - if (!t) + local_t = btf__type_by_id(local_btf, local_type_id); + if (!local_t) return ERR_PTR(-EINVAL); - local_name = btf__name_by_offset(local_btf, t->name_off); + local_name = btf__name_by_offset(local_btf, local_t->name_off); if (str_is_empty(local_name)) return ERR_PTR(-EINVAL); local_essent_len = bpf_core_essential_name_len(local_name); @@ -4310,6 +4348,7 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, targ_name = btf__name_by_offset(targ_btf, t->name_off); if (str_is_empty(targ_name)) continue; + targ_kind = btf_kind_str(t); t = skip_mods_and_typedefs(targ_btf, i, NULL); if (!btf_is_composite(t) && !btf_is_array(t)) @@ -4320,8 +4359,9 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, continue; if (strncmp(local_name, targ_name, local_essent_len) == 0) { - pr_debug("[%d] %s: found candidate [%d] %s\n", - local_type_id, local_name, i, targ_name); + pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n", + local_type_id, btf_kind_str(local_t), + local_name, i, targ_kind, targ_name); new_ids = reallocarray(cand_ids->data, cand_ids->len + 1, sizeof(*cand_ids->data)); @@ -4510,6 +4550,8 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec, memset(targ_spec, 0, sizeof(*targ_spec)); targ_spec->btf = targ_btf; + targ_spec->root_type_id = targ_id; + targ_spec->relo_kind = local_spec->relo_kind; local_acc = &local_spec->spec[0]; targ_acc = &targ_spec->spec[0]; @@ -4570,7 +4612,7 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec, } static int bpf_core_calc_field_relo(const struct bpf_program *prog, - const struct bpf_field_reloc *relo, + const struct bpf_core_relo *relo, const struct bpf_core_spec *spec, __u32 *val, bool *validate) { @@ -4691,7 +4733,7 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, * 2. rX += (arithmetic operations with immediate operand); */ static int bpf_core_reloc_insn(struct bpf_program *prog, - const struct bpf_field_reloc *relo, + const struct bpf_core_relo *relo, int relo_idx, const struct bpf_core_spec *local_spec, const struct bpf_core_spec *targ_spec) @@ -4795,25 +4837,30 @@ static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) __u32 type_id; int i; - type_id = spec->spec[0].type_id; + type_id = spec->root_type_id; t = btf__type_by_id(spec->btf, type_id); s = btf__name_by_offset(spec->btf, t->name_off); - libbpf_print(level, "[%u] %s + ", type_id, s); - for (i = 0; i < spec->raw_len; i++) - libbpf_print(level, "%d%s", spec->raw_spec[i], - i == spec->raw_len - 1 ? " => " : ":"); + libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "" : s); + + if (core_relo_is_field_based(spec->relo_kind)) { + for (i = 0; i < spec->len; i++) { + if (spec->spec[i].name) + libbpf_print(level, ".%s", spec->spec[i].name); + else if (i > 0 || spec->spec[i].idx > 0) + libbpf_print(level, "[%u]", spec->spec[i].idx); + } - libbpf_print(level, "%u.%u @ &x", - spec->bit_offset / 8, spec->bit_offset % 8); + libbpf_print(level, " ("); + for (i = 0; i < spec->raw_len; i++) + libbpf_print(level, "%s%d", i == 0 ? "" : ":", spec->raw_spec[i]); - for (i = 0; i < spec->len; i++) { - if (spec->spec[i].name) - libbpf_print(level, ".%s", spec->spec[i].name); + if (spec->bit_offset % 8) + libbpf_print(level, " @ offset %u.%u)", + spec->bit_offset / 8, spec->bit_offset % 8); else - libbpf_print(level, "[%u]", spec->spec[i].idx); + libbpf_print(level, " @ offset %u)", spec->bit_offset / 8); } - } static size_t bpf_core_hash_fn(const void *key, void *ctx) @@ -4877,12 +4924,12 @@ static void *u32_as_hash_key(__u32 x) * CPU-wise compared to prebuilding a map from all local type names to * a list of candidate type names. It's also sped up by caching resolved * list of matching candidates per each local "root" type ID, that has at - * least one bpf_field_reloc associated with it. This list is shared + * least one bpf_core_relo associated with it. This list is shared * between multiple relocations for the same type ID and is updated as some * of the candidates are pruned due to structural incompatibility. */ static int bpf_core_reloc_field(struct bpf_program *prog, - const struct bpf_field_reloc *relo, + const struct bpf_core_relo *relo, int relo_idx, const struct btf *local_btf, const struct btf *targ_btf, @@ -4891,8 +4938,8 @@ static int bpf_core_reloc_field(struct bpf_program *prog, const char *prog_name = bpf_program__title(prog, false); struct bpf_core_spec local_spec, cand_spec, targ_spec; const void *type_key = u32_as_hash_key(relo->type_id); - const struct btf_type *local_type, *cand_type; - const char *local_name, *cand_name; + const struct btf_type *local_type; + const char *local_name; struct ids_vec *cand_ids; __u32 local_id, cand_id; const char *spec_str; @@ -4911,24 +4958,24 @@ static int bpf_core_reloc_field(struct bpf_program *prog, if (str_is_empty(spec_str)) return -EINVAL; - err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec); + err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec); if (err) { - pr_warn("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n", - prog_name, relo_idx, local_id, local_name, spec_str, - err); + pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n", + prog_name, relo_idx, local_id, btf_kind_str(local_type), + local_name, spec_str, err); return -EINVAL; } - pr_debug("prog '%s': relo #%d: kind %d, spec is ", prog_name, relo_idx, - relo->kind); + pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog_name, + relo_idx, core_relo_kind_str(relo->kind), relo->kind); bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec); libbpf_print(LIBBPF_DEBUG, "\n"); if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) { cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf); if (IS_ERR(cand_ids)) { - pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld", - prog_name, relo_idx, local_id, local_name, + pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld", + prog_name, relo_idx, local_id, btf_kind_str(local_type), local_name, PTR_ERR(cand_ids)); return PTR_ERR(cand_ids); } @@ -4941,20 +4988,20 @@ static int bpf_core_reloc_field(struct bpf_program *prog, for (i = 0, j = 0; i < cand_ids->len; i++) { cand_id = cand_ids->data[i]; - cand_type = btf__type_by_id(targ_btf, cand_id); - cand_name = btf__name_by_offset(targ_btf, cand_type->name_off); - - err = bpf_core_spec_match(&local_spec, targ_btf, - cand_id, &cand_spec); - pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ", - prog_name, relo_idx, i, cand_name); - bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec); - libbpf_print(LIBBPF_DEBUG, ": %d\n", err); + err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec); if (err < 0) { - pr_warn("prog '%s': relo #%d: matching error: %d\n", - prog_name, relo_idx, err); + pr_warn("prog '%s': relo #%d: error matching candidate #%d ", + prog_name, relo_idx, i); + bpf_core_dump_spec(LIBBPF_WARN, &cand_spec); + libbpf_print(LIBBPF_WARN, ": %d\n", err); return err; } + + pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog_name, + relo_idx, err == 0 ? "non-matching" : "matching", i); + bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec); + libbpf_print(LIBBPF_DEBUG, "\n"); + if (err == 0) continue; @@ -4996,8 +5043,8 @@ static int bpf_core_reloc_field(struct bpf_program *prog, * to a specific instruction number in its log. */ if (j == 0) - pr_debug("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n", - prog_name, relo_idx, local_id, local_name, spec_str); + pr_debug("prog '%s': relo #%d: no matching targets found\n", + prog_name, relo_idx); /* bpf_core_reloc_insn should know how to handle missing targ_spec */ err = bpf_core_reloc_insn(prog, relo, relo_idx, &local_spec, @@ -5012,10 +5059,10 @@ static int bpf_core_reloc_field(struct bpf_program *prog, } static int -bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path) +bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) { const struct btf_ext_info_sec *sec; - const struct bpf_field_reloc *rec; + const struct bpf_core_relo *rec; const struct btf_ext_info *seg; struct hashmap_entry *entry; struct hashmap *cand_cache = NULL; @@ -5024,6 +5071,9 @@ bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path) const char *sec_name; int i, err = 0; + if (obj->btf_ext->core_relo_info.len == 0) + return 0; + if (targ_btf_path) targ_btf = btf__parse_elf(targ_btf_path, NULL); else @@ -5039,7 +5089,7 @@ bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path) goto out; } - seg = &obj->btf_ext->field_reloc_info; + seg = &obj->btf_ext->core_relo_info; for_each_btf_ext_sec(seg, sec) { sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); if (str_is_empty(sec_name)) { @@ -5087,17 +5137,6 @@ out: return err; } -static int -bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) -{ - int err = 0; - - if (obj->btf_ext->field_reloc_info.len) - err = bpf_core_reloc_fields(obj, targ_btf_path); - - return err; -} - static int bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj, struct reloc_desc *relo) diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 50d70e90d5f1..b776a7125c92 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -138,6 +138,44 @@ struct btf_ext_info { i < (sec)->num_info; \ i++, rec = (void *)rec + (seg)->rec_size) +/* + * The .BTF.ext ELF section layout defined as + * struct btf_ext_header + * func_info subsection + * + * The func_info subsection layout: + * record size for struct bpf_func_info in the func_info subsection + * struct btf_sec_func_info for section #1 + * a list of bpf_func_info records for section #1 + * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h + * but may not be identical + * struct btf_sec_func_info for section #2 + * a list of bpf_func_info records for section #2 + * ...... + * + * Note that the bpf_func_info record size in .BTF.ext may not + * be the same as the one defined in include/uapi/linux/bpf.h. + * The loader should ensure that record_size meets minimum + * requirement and pass the record as is to the kernel. The + * kernel will handle the func_info properly based on its contents. + */ +struct btf_ext_header { + __u16 magic; + __u8 version; + __u8 flags; + __u32 hdr_len; + + /* All offsets are in bytes relative to the end of this header */ + __u32 func_info_off; + __u32 func_info_len; + __u32 line_info_off; + __u32 line_info_len; + + /* optional part of .BTF.ext header */ + __u32 core_relo_off; + __u32 core_relo_len; +}; + struct btf_ext { union { struct btf_ext_header *hdr; @@ -145,7 +183,7 @@ struct btf_ext { }; struct btf_ext_info func_info; struct btf_ext_info line_info; - struct btf_ext_info field_reloc_info; + struct btf_ext_info core_relo_info; __u32 data_size; }; @@ -170,32 +208,34 @@ struct bpf_line_info_min { __u32 line_col; }; -/* bpf_field_info_kind encodes which aspect of captured field has to be - * adjusted by relocations. Currently supported values are: - * - BPF_FIELD_BYTE_OFFSET: field offset (in bytes); - * - BPF_FIELD_EXISTS: field existence (1, if field exists; 0, otherwise); +/* bpf_core_relo_kind encodes which aspect of captured field/type/enum value + * has to be adjusted by relocations. */ -enum bpf_field_info_kind { +enum bpf_core_relo_kind { BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ - BPF_FIELD_BYTE_SIZE = 1, + BPF_FIELD_BYTE_SIZE = 1, /* field size in bytes */ BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ - BPF_FIELD_SIGNED = 3, - BPF_FIELD_LSHIFT_U64 = 4, - BPF_FIELD_RSHIFT_U64 = 5, + BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */ + BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */ + BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */ }; -/* The minimum bpf_field_reloc checked by the loader +/* The minimum bpf_core_relo checked by the loader * - * Field relocation captures the following data: + * CO-RE relocation captures the following data: * - insn_off - instruction offset (in bytes) within a BPF program that needs * its insn->imm field to be relocated with actual field info; * - type_id - BTF type ID of the "root" (containing) entity of a relocatable - * field; + * type or field; * - access_str_off - offset into corresponding .BTF string section. String - * itself encodes an accessed field using a sequence of field and array - * indicies, separated by colon (:). It's conceptually very close to LLVM's - * getelementptr ([0]) instruction's arguments for identifying offset to - * a field. + * interpretation depends on specific relocation kind: + * - for field-based relocations, string encodes an accessed field using + * a sequence of field and array indices, separated by colon (:). It's + * conceptually very close to LLVM's getelementptr ([0]) instruction's + * arguments for identifying offset to a field. + * - for type-based relocations, strings is expected to be just "0"; + * - for enum value-based relocations, string contains an index of enum + * value within its enum type; * * Example to provide a better feel. * @@ -226,11 +266,11 @@ enum bpf_field_info_kind { * * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction */ -struct bpf_field_reloc { +struct bpf_core_relo { __u32 insn_off; __u32 type_id; __u32 access_str_off; - enum bpf_field_info_kind kind; + enum bpf_core_relo_kind kind; }; #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ -- cgit v1.2.3 From 353c788c2054257359114f12827d86f8e3332e10 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 15:39:15 -0700 Subject: libbpf: Improve relocation ambiguity detection Split the instruction patching logic into relocation value calculation and application of relocation to instruction. Using this, evaluate relocation against each matching candidate and validate that all candidates agree on relocated value. If not, report ambiguity and fail load. This logic is necessary to avoid dangerous (however unlikely) accidental match against two incompatible candidate types. Without this change, libbpf will pick a random type as *the* candidate and apply potentially invalid relocation. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818223921.2911963-4-andriin@fb.com --- tools/lib/bpf/libbpf.c | 170 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 124 insertions(+), 46 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 894d388094e3..0276cf85d763 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4616,14 +4616,25 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, const struct bpf_core_spec *spec, __u32 *val, bool *validate) { - const struct bpf_core_accessor *acc = &spec->spec[spec->len - 1]; - const struct btf_type *t = btf__type_by_id(spec->btf, acc->type_id); + const struct bpf_core_accessor *acc; + const struct btf_type *t; __u32 byte_off, byte_sz, bit_off, bit_sz; const struct btf_member *m; const struct btf_type *mt; bool bitfield; __s64 sz; + if (relo->kind == BPF_FIELD_EXISTS) { + *val = spec ? 1 : 0; + return 0; + } + + if (!spec) + return -EUCLEAN; /* request instruction poisoning */ + + acc = &spec->spec[spec->len - 1]; + t = btf__type_by_id(spec->btf, acc->type_id); + /* a[n] accessor needs special handling */ if (!acc->name) { if (relo->kind == BPF_FIELD_BYTE_OFFSET) { @@ -4709,21 +4720,88 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, break; case BPF_FIELD_EXISTS: default: - pr_warn("prog '%s': unknown relo %d at insn #%d\n", - bpf_program__title(prog, false), - relo->kind, relo->insn_off / 8); - return -EINVAL; + return -EOPNOTSUPP; } return 0; } +struct bpf_core_relo_res +{ + /* expected value in the instruction, unless validate == false */ + __u32 orig_val; + /* new value that needs to be patched up to */ + __u32 new_val; + /* relocation unsuccessful, poison instruction, but don't fail load */ + bool poison; + /* some relocations can't be validated against orig_val */ + bool validate; +}; + +/* Calculate original and target relocation values, given local and target + * specs and relocation kind. These values are calculated for each candidate. + * If there are multiple candidates, resulting values should all be consistent + * with each other. Otherwise, libbpf will refuse to proceed due to ambiguity. + * If instruction has to be poisoned, *poison will be set to true. + */ +static int bpf_core_calc_relo(const struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct bpf_core_spec *local_spec, + const struct bpf_core_spec *targ_spec, + struct bpf_core_relo_res *res) +{ + int err = -EOPNOTSUPP; + + res->orig_val = 0; + res->new_val = 0; + res->poison = false; + res->validate = true; + + if (core_relo_is_field_based(relo->kind)) { + err = bpf_core_calc_field_relo(prog, relo, local_spec, &res->orig_val, &res->validate); + err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec, &res->new_val, NULL); + } + + if (err == -EUCLEAN) { + /* EUCLEAN is used to signal instruction poisoning request */ + res->poison = true; + err = 0; + } else if (err == -EOPNOTSUPP) { + /* EOPNOTSUPP means unknown/unsupported relocation */ + pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%d) at insn #%d\n", + bpf_program__title(prog, false), relo_idx, + core_relo_kind_str(relo->kind), relo->kind, relo->insn_off / 8); + } + + return err; +} + +/* + * Turn instruction for which CO_RE relocation failed into invalid one with + * distinct signature. + */ +static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn) +{ + pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n", + bpf_program__title(prog, false), relo_idx, insn_idx); + insn->code = BPF_JMP | BPF_CALL; + insn->dst_reg = 0; + insn->src_reg = 0; + insn->off = 0; + /* if this instruction is reachable (not a dead code), + * verifier will complain with the following message: + * invalid func unknown#195896080 + */ + insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */ +} + /* * Patch relocatable BPF instruction. * * Patched value is determined by relocation kind and target specification. - * For field existence relocation target spec will be NULL if field is not - * found. + * For existence relocations target spec will be NULL if field/type is not found. * Expected insn->imm value is determined using relocation kind and local * spec, and is checked before patching instruction. If actual insn->imm value * is wrong, bail out with error. @@ -4732,16 +4810,14 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, * 1. rX = (assignment with immediate operand); * 2. rX += (arithmetic operations with immediate operand); */ -static int bpf_core_reloc_insn(struct bpf_program *prog, +static int bpf_core_patch_insn(struct bpf_program *prog, const struct bpf_core_relo *relo, int relo_idx, - const struct bpf_core_spec *local_spec, - const struct bpf_core_spec *targ_spec) + const struct bpf_core_relo_res *res) { __u32 orig_val, new_val; struct bpf_insn *insn; - bool validate = true; - int insn_idx, err; + int insn_idx; __u8 class; if (relo->insn_off % sizeof(struct bpf_insn)) @@ -4750,39 +4826,20 @@ static int bpf_core_reloc_insn(struct bpf_program *prog, insn = &prog->insns[insn_idx]; class = BPF_CLASS(insn->code); - if (relo->kind == BPF_FIELD_EXISTS) { - orig_val = 1; /* can't generate EXISTS relo w/o local field */ - new_val = targ_spec ? 1 : 0; - } else if (!targ_spec) { - pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n", - bpf_program__title(prog, false), relo_idx, insn_idx); - insn->code = BPF_JMP | BPF_CALL; - insn->dst_reg = 0; - insn->src_reg = 0; - insn->off = 0; - /* if this instruction is reachable (not a dead code), - * verifier will complain with the following message: - * invalid func unknown#195896080 - */ - insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */ + if (res->poison) { + bpf_core_poison_insn(prog, relo_idx, insn_idx, insn); return 0; - } else { - err = bpf_core_calc_field_relo(prog, relo, local_spec, - &orig_val, &validate); - if (err) - return err; - err = bpf_core_calc_field_relo(prog, relo, targ_spec, - &new_val, NULL); - if (err) - return err; } + orig_val = res->orig_val; + new_val = res->new_val; + switch (class) { case BPF_ALU: case BPF_ALU64: if (BPF_SRC(insn->code) != BPF_K) return -EINVAL; - if (validate && insn->imm != orig_val) { + if (res->validate && insn->imm != orig_val) { pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n", bpf_program__title(prog, false), relo_idx, insn_idx, insn->imm, orig_val, new_val); @@ -4797,7 +4854,7 @@ static int bpf_core_reloc_insn(struct bpf_program *prog, case BPF_LDX: case BPF_ST: case BPF_STX: - if (validate && insn->off != orig_val) { + if (res->validate && insn->off != orig_val) { pr_warn("prog '%s': relo #%d: unexpected insn #%d (LD/LDX/ST/STX) value: got %u, exp %u -> %u\n", bpf_program__title(prog, false), relo_idx, insn_idx, insn->off, orig_val, new_val); @@ -4938,6 +4995,7 @@ static int bpf_core_reloc_field(struct bpf_program *prog, const char *prog_name = bpf_program__title(prog, false); struct bpf_core_spec local_spec, cand_spec, targ_spec; const void *type_key = u32_as_hash_key(relo->type_id); + struct bpf_core_relo_res cand_res, targ_res; const struct btf_type *local_type; const char *local_name; struct ids_vec *cand_ids; @@ -5005,16 +5063,31 @@ static int bpf_core_reloc_field(struct bpf_program *prog, if (err == 0) continue; + err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, &cand_spec, &cand_res); + if (err) + return err; + if (j == 0) { + targ_res = cand_res; targ_spec = cand_spec; } else if (cand_spec.bit_offset != targ_spec.bit_offset) { - /* if there are many candidates, they should all - * resolve to the same bit offset + /* if there are many field relo candidates, they + * should all resolve to the same bit offset */ - pr_warn("prog '%s': relo #%d: offset ambiguity: %u != %u\n", + pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n", prog_name, relo_idx, cand_spec.bit_offset, targ_spec.bit_offset); return -EINVAL; + } else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) { + /* all candidates should result in the same relocation + * decision and value, otherwise it's dangerous to + * proceed due to ambiguity + */ + pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n", + prog_name, relo_idx, + cand_res.poison ? "failure" : "success", cand_res.new_val, + targ_res.poison ? "failure" : "success", targ_res.new_val); + return -EINVAL; } cand_ids->data[j++] = cand_spec.spec[0].type_id; @@ -5042,13 +5115,18 @@ static int bpf_core_reloc_field(struct bpf_program *prog, * verifier. If it was an error, then verifier will complain and point * to a specific instruction number in its log. */ - if (j == 0) + if (j == 0) { pr_debug("prog '%s': relo #%d: no matching targets found\n", prog_name, relo_idx); - /* bpf_core_reloc_insn should know how to handle missing targ_spec */ - err = bpf_core_reloc_insn(prog, relo, relo_idx, &local_spec, - j ? &targ_spec : NULL); + /* calculate single target relo result explicitly */ + err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, NULL, &targ_res); + if (err) + return err; + } + + /* bpf_core_patch_insn() should know how to handle missing targ_spec */ + err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n", prog_name, relo_idx, relo->insn_off, err); -- cgit v1.2.3 From 029258d7b22894fabcecb1626e1b87d18a6823f4 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 18:36:04 -0700 Subject: libbpf: Remove any use of reallocarray() in libbpf Re-implement glibc's reallocarray() for libbpf internal-only use. reallocarray(), unfortunately, is not available in all versions of glibc, so requires extra feature detection and using reallocarray() stub from and COMPAT_NEED_REALLOCARRAY. All this complicates build of libbpf unnecessarily and is just a maintenance burden. Instead, it's trivial to implement libbpf-specific internal version and use it throughout libbpf. Which is what this patch does, along with converting some realloc() uses that should really have been reallocarray() in the first place. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200819013607.3607269-2-andriin@fb.com --- tools/lib/bpf/Makefile | 6 +----- tools/lib/bpf/btf.c | 11 +++++------ tools/lib/bpf/btf_dump.c | 6 ++---- tools/lib/bpf/libbpf.c | 21 ++++++++++----------- tools/lib/bpf/libbpf_internal.h | 25 +++++++++++++++++++++++++ tools/lib/bpf/ringbuf.c | 5 ++--- 6 files changed, 45 insertions(+), 29 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 95c946e94ca5..621ad96d06fd 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -56,7 +56,7 @@ ifndef VERBOSE endif FEATURE_USER = .libbpf -FEATURE_TESTS = libelf libelf-mmap zlib bpf reallocarray +FEATURE_TESTS = libelf libelf-mmap zlib bpf FEATURE_DISPLAY = libelf zlib bpf INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi @@ -102,10 +102,6 @@ ifeq ($(feature-libelf-mmap), 1) override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT endif -ifeq ($(feature-reallocarray), 0) - override CFLAGS += -DCOMPAT_NEED_REALLOCARRAY -endif - # Append required CFLAGS override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum override CFLAGS += -Werror -Wall diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 1deedbd19c6c..1b7d85d94a07 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -61,7 +61,7 @@ static int btf_add_type(struct btf *btf, struct btf_type *t) expand_by = max(btf->types_size >> 2, 16U); new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by); - new_types = realloc(btf->types, sizeof(*new_types) * new_size); + new_types = libbpf_reallocarray(btf->types, new_size, sizeof(*new_types)); if (!new_types) return -ENOMEM; @@ -1574,7 +1574,7 @@ static int btf_dedup_hypot_map_add(struct btf_dedup *d, __u32 *new_list; d->hypot_cap += max((size_t)16, d->hypot_cap / 2); - new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap); + new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32)); if (!new_list) return -ENOMEM; d->hypot_list = new_list; @@ -1870,8 +1870,7 @@ static int btf_dedup_strings(struct btf_dedup *d) struct btf_str_ptr *new_ptrs; strs.cap += max(strs.cnt / 2, 16U); - new_ptrs = realloc(strs.ptrs, - sizeof(strs.ptrs[0]) * strs.cap); + new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0])); if (!new_ptrs) { err = -ENOMEM; goto done; @@ -2956,8 +2955,8 @@ static int btf_dedup_compact_types(struct btf_dedup *d) d->btf->nr_types = next_type_id - 1; d->btf->types_size = d->btf->nr_types; d->btf->hdr->type_len = p - types_start; - new_types = realloc(d->btf->types, - (1 + d->btf->nr_types) * sizeof(struct btf_type *)); + new_types = libbpf_reallocarray(d->btf->types, (1 + d->btf->nr_types), + sizeof(struct btf_type *)); if (!new_types) return -ENOMEM; d->btf->types = new_types; diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index fe39bd774697..1ad852ad0a86 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -323,8 +323,7 @@ static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id) if (d->emit_queue_cnt >= d->emit_queue_cap) { new_cap = max(16, d->emit_queue_cap * 3 / 2); - new_queue = realloc(d->emit_queue, - new_cap * sizeof(new_queue[0])); + new_queue = libbpf_reallocarray(d->emit_queue, new_cap, sizeof(new_queue[0])); if (!new_queue) return -ENOMEM; d->emit_queue = new_queue; @@ -1003,8 +1002,7 @@ static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id) if (d->decl_stack_cnt >= d->decl_stack_cap) { new_cap = max(16, d->decl_stack_cap * 3 / 2); - new_stack = realloc(d->decl_stack, - new_cap * sizeof(new_stack[0])); + new_stack = libbpf_reallocarray(d->decl_stack, new_cap, sizeof(new_stack[0])); if (!new_stack) return -ENOMEM; d->decl_stack = new_stack; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0276cf85d763..2653bcee73b7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -44,7 +44,6 @@ #include #include #include -#include #include #include #include @@ -567,7 +566,7 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, progs = obj->programs; nr_progs = obj->nr_programs; - progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0])); + progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(progs[0])); if (!progs) { /* * In this case the original obj->programs @@ -1292,7 +1291,7 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) return &obj->maps[obj->nr_maps++]; new_cap = max((size_t)4, obj->maps_cap * 3 / 2); - new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps)); + new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps)); if (!new_maps) { pr_warn("alloc maps for object failed\n"); return ERR_PTR(-ENOMEM); @@ -2721,8 +2720,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) continue; } - sects = reallocarray(sects, nr_sects + 1, - sizeof(*obj->efile.reloc_sects)); + sects = libbpf_reallocarray(sects, nr_sects + 1, + sizeof(*obj->efile.reloc_sects)); if (!sects) { pr_warn("reloc_sects realloc failed\n"); return -ENOMEM; @@ -2925,7 +2924,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj) continue; ext = obj->externs; - ext = reallocarray(ext, obj->nr_extern + 1, sizeof(*ext)); + ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext)); if (!ext) return -ENOMEM; obj->externs = ext; @@ -4362,9 +4361,9 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n", local_type_id, btf_kind_str(local_t), local_name, i, targ_kind, targ_name); - new_ids = reallocarray(cand_ids->data, - cand_ids->len + 1, - sizeof(*cand_ids->data)); + new_ids = libbpf_reallocarray(cand_ids->data, + cand_ids->len + 1, + sizeof(*cand_ids->data)); if (!new_ids) { err = -ENOMEM; goto err_out; @@ -5231,7 +5230,7 @@ bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj, return -LIBBPF_ERRNO__RELOC; } new_cnt = prog->insns_cnt + text->insns_cnt; - new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn)); + new_insn = libbpf_reallocarray(prog->insns, new_cnt, sizeof(*insn)); if (!new_insn) { pr_warn("oom in prog realloc\n"); return -ENOMEM; @@ -5473,7 +5472,7 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, moff /= bpf_ptr_sz; if (moff >= map->init_slots_sz) { new_sz = moff + 1; - tmp = realloc(map->init_slots, new_sz * host_ptr_sz); + tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz); if (!tmp) return -ENOMEM; map->init_slots = tmp; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index b776a7125c92..954bc2bd040c 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -9,6 +9,7 @@ #ifndef __LIBBPF_LIBBPF_INTERNAL_H #define __LIBBPF_LIBBPF_INTERNAL_H +#include #include "libbpf.h" #define BTF_INFO_ENC(kind, kind_flag, vlen) \ @@ -23,6 +24,12 @@ #define BTF_PARAM_ENC(name, type) (name), (type) #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) +#ifndef likely +#define likely(x) __builtin_expect(!!(x), 1) +#endif +#ifndef unlikely +#define unlikely(x) __builtin_expect(!!(x), 0) +#endif #ifndef min # define min(x, y) ((x) < (y) ? (x) : (y)) #endif @@ -63,6 +70,24 @@ do { \ #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) +/* + * Re-implement glibc's reallocarray() for libbpf internal-only use. + * reallocarray(), unfortunately, is not available in all versions of glibc, + * so requires extra feature detection and using reallocarray() stub from + * and COMPAT_NEED_REALLOCARRAY. All this complicates + * build of libbpf unnecessarily and is just a maintenance burden. Instead, + * it's trivial to implement libbpf-specific internal version and use it + * throughout libbpf. + */ +static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) +{ + size_t total; + + if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) + return NULL; + return realloc(ptr, total); +} + static inline bool libbpf_validate_opts(const char *opts, size_t opts_sz, size_t user_sz, const char *type_name) diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index 4fc6c6cbb4eb..5bd234be8a14 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -16,7 +16,6 @@ #include #include #include -#include #include "libbpf.h" #include "libbpf_internal.h" @@ -82,12 +81,12 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd, return -EINVAL; } - tmp = reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings)); + tmp = libbpf_reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings)); if (!tmp) return -ENOMEM; rb->rings = tmp; - tmp = reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events)); + tmp = libbpf_reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events)); if (!tmp) return -ENOMEM; rb->events = tmp; -- cgit v1.2.3 From 7084566a236fbc98beb11430d8d67dd08b2ac151 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 18:36:05 -0700 Subject: tools/bpftool: Remove libbpf_internal.h usage in bpftool Most netlink-related functions were unique to bpftool usage, so I moved them into net.c. Few functions are still used by both bpftool and libbpf itself internally, so I've copy-pasted them (libbpf_nl_get_link, libbpf_netlink_open). It's a bit of duplication of code, but better separation of libbpf as a library with public API and bpftool, relying on unexposed functions in libbpf. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200819013607.3607269-3-andriin@fb.com --- tools/lib/bpf/libbpf_internal.h | 12 ---- tools/lib/bpf/netlink.c | 125 ++-------------------------------------- 2 files changed, 6 insertions(+), 131 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 954bc2bd040c..65931e989eea 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -130,18 +130,6 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name, int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, __u32 *off); -struct nlattr; -typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb); -int libbpf_netlink_open(unsigned int *nl_pid); -int libbpf_nl_get_link(int sock, unsigned int nl_pid, - libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie); -int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex, - libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie); -int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex, - libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie); -int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle, - libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie); - struct btf_ext_info { /* * info points to the individual info section (e.g. func_info and diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c index 312f887570b2..2465538a5ba9 100644 --- a/tools/lib/bpf/netlink.c +++ b/tools/lib/bpf/netlink.c @@ -22,6 +22,8 @@ #define SOL_NETLINK 270 #endif +typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb); + typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t, void *cookie); @@ -31,7 +33,7 @@ struct xdp_id_md { struct xdp_link_info info; }; -int libbpf_netlink_open(__u32 *nl_pid) +static int libbpf_netlink_open(__u32 *nl_pid) { struct sockaddr_nl sa; socklen_t addrlen; @@ -283,6 +285,9 @@ static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb) return 0; } +static int libbpf_nl_get_link(int sock, unsigned int nl_pid, + libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie); + int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info, size_t info_size, __u32 flags) { @@ -368,121 +373,3 @@ int libbpf_nl_get_link(int sock, unsigned int nl_pid, return bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg, dump_link_nlmsg, cookie); } - -static int __dump_class_nlmsg(struct nlmsghdr *nlh, - libbpf_dump_nlmsg_t dump_class_nlmsg, - void *cookie) -{ - struct nlattr *tb[TCA_MAX + 1], *attr; - struct tcmsg *t = NLMSG_DATA(nlh); - int len; - - len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t)); - attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t))); - if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0) - return -LIBBPF_ERRNO__NLPARSE; - - return dump_class_nlmsg(cookie, t, tb); -} - -int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex, - libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie) -{ - struct { - struct nlmsghdr nlh; - struct tcmsg t; - } req = { - .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)), - .nlh.nlmsg_type = RTM_GETTCLASS, - .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, - .t.tcm_family = AF_UNSPEC, - .t.tcm_ifindex = ifindex, - }; - int seq = time(NULL); - - req.nlh.nlmsg_seq = seq; - if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) - return -errno; - - return bpf_netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg, - dump_class_nlmsg, cookie); -} - -static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh, - libbpf_dump_nlmsg_t dump_qdisc_nlmsg, - void *cookie) -{ - struct nlattr *tb[TCA_MAX + 1], *attr; - struct tcmsg *t = NLMSG_DATA(nlh); - int len; - - len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t)); - attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t))); - if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0) - return -LIBBPF_ERRNO__NLPARSE; - - return dump_qdisc_nlmsg(cookie, t, tb); -} - -int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex, - libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie) -{ - struct { - struct nlmsghdr nlh; - struct tcmsg t; - } req = { - .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)), - .nlh.nlmsg_type = RTM_GETQDISC, - .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, - .t.tcm_family = AF_UNSPEC, - .t.tcm_ifindex = ifindex, - }; - int seq = time(NULL); - - req.nlh.nlmsg_seq = seq; - if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) - return -errno; - - return bpf_netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg, - dump_qdisc_nlmsg, cookie); -} - -static int __dump_filter_nlmsg(struct nlmsghdr *nlh, - libbpf_dump_nlmsg_t dump_filter_nlmsg, - void *cookie) -{ - struct nlattr *tb[TCA_MAX + 1], *attr; - struct tcmsg *t = NLMSG_DATA(nlh); - int len; - - len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t)); - attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t))); - if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0) - return -LIBBPF_ERRNO__NLPARSE; - - return dump_filter_nlmsg(cookie, t, tb); -} - -int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle, - libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie) -{ - struct { - struct nlmsghdr nlh; - struct tcmsg t; - } req = { - .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)), - .nlh.nlmsg_type = RTM_GETTFILTER, - .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, - .t.tcm_family = AF_UNSPEC, - .t.tcm_ifindex = ifindex, - .t.tcm_parent = handle, - }; - int seq = time(NULL); - - req.nlh.nlmsg_seq = seq; - if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) - return -errno; - - return bpf_netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg, - dump_filter_nlmsg, cookie); -} -- cgit v1.2.3 From 85367030a6c7ef3373347cf816c698995074f6f0 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 18:36:06 -0700 Subject: libbpf: Centralize poisoning and poison reallocarray() Most of libbpf source files already include libbpf_internal.h, so it's a good place to centralize identifier poisoning. So move kernel integer type poisoning there. And also add reallocarray to a poison list to prevent accidental use of it. libbpf_reallocarray() should be used universally instead. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200819013607.3607269-4-andriin@fb.com --- tools/lib/bpf/bpf.c | 3 --- tools/lib/bpf/bpf_prog_linfo.c | 3 --- tools/lib/bpf/btf.c | 3 --- tools/lib/bpf/btf_dump.c | 3 --- tools/lib/bpf/hashmap.c | 3 +++ tools/lib/bpf/libbpf.c | 3 --- tools/lib/bpf/libbpf_internal.h | 7 +++++++ tools/lib/bpf/libbpf_probes.c | 3 --- tools/lib/bpf/netlink.c | 3 --- tools/lib/bpf/nlattr.c | 9 +++------ tools/lib/bpf/ringbuf.c | 3 --- tools/lib/bpf/xsk.c | 3 --- 12 files changed, 13 insertions(+), 33 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 0750681057c2..82b983ff6569 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -32,9 +32,6 @@ #include "libbpf.h" #include "libbpf_internal.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - /* * When building perf, unistd.h is overridden. __NR_bpf is * required to be defined explicitly. diff --git a/tools/lib/bpf/bpf_prog_linfo.c b/tools/lib/bpf/bpf_prog_linfo.c index bafca49cb1e6..3ed1a27b5f7c 100644 --- a/tools/lib/bpf/bpf_prog_linfo.c +++ b/tools/lib/bpf/bpf_prog_linfo.c @@ -8,9 +8,6 @@ #include "libbpf.h" #include "libbpf_internal.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - struct bpf_prog_linfo { void *raw_linfo; void *raw_jited_linfo; diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 1b7d85d94a07..a3d259e614b0 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -21,9 +21,6 @@ #include "libbpf_internal.h" #include "hashmap.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - #define BTF_MAX_NR_TYPES 0x7fffffffU #define BTF_MAX_STR_OFFSET 0x7fffffffU diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 1ad852ad0a86..0eaafd9bcfea 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -19,9 +19,6 @@ #include "libbpf.h" #include "libbpf_internal.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t"; static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1; diff --git a/tools/lib/bpf/hashmap.c b/tools/lib/bpf/hashmap.c index a405dad068f5..3c20b126d60d 100644 --- a/tools/lib/bpf/hashmap.c +++ b/tools/lib/bpf/hashmap.c @@ -15,6 +15,9 @@ /* make sure libbpf doesn't use kernel-only integer typedefs */ #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 +/* prevent accidental re-addition of reallocarray() */ +#pragma GCC poison reallocarray + /* start with 4 buckets */ #define HASHMAP_MIN_CAP_BITS 2 diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2653bcee73b7..4b96e0eefea8 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -55,9 +55,6 @@ #include "libbpf_internal.h" #include "hashmap.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - #ifndef EM_BPF #define EM_BPF 247 #endif diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 65931e989eea..c8ed352671d5 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -10,6 +10,13 @@ #define __LIBBPF_LIBBPF_INTERNAL_H #include + +/* make sure libbpf doesn't use kernel-only integer typedefs */ +#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 + +/* prevent accidental re-addition of reallocarray() */ +#pragma GCC poison reallocarray + #include "libbpf.h" #define BTF_INFO_ENC(kind, kind_flag, vlen) \ diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index 5a3d3f078408..010c9a76fd2b 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -17,9 +17,6 @@ #include "libbpf.h" #include "libbpf_internal.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - static bool grep(const char *buffer, const char *pattern) { return !!strstr(buffer, pattern); diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c index 2465538a5ba9..4dd73de00b6f 100644 --- a/tools/lib/bpf/netlink.c +++ b/tools/lib/bpf/netlink.c @@ -15,9 +15,6 @@ #include "libbpf_internal.h" #include "nlattr.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - #ifndef SOL_NETLINK #define SOL_NETLINK 270 #endif diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c index 0ad41dfea8eb..b607fa9852b1 100644 --- a/tools/lib/bpf/nlattr.c +++ b/tools/lib/bpf/nlattr.c @@ -7,14 +7,11 @@ */ #include -#include "nlattr.h" -#include "libbpf_internal.h" -#include #include #include - -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 +#include +#include "nlattr.h" +#include "libbpf_internal.h" static uint16_t nla_attr_minlen[LIBBPF_NLA_TYPE_MAX+1] = { [LIBBPF_NLA_U8] = sizeof(uint8_t), diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index 5bd234be8a14..5c6522c89af1 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -21,9 +21,6 @@ #include "libbpf_internal.h" #include "bpf.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - struct ring { ring_buffer_sample_fn sample_cb; void *ctx; diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index f7f4efb70a4c..a9b02103767b 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -32,9 +32,6 @@ #include "libbpf_internal.h" #include "xsk.h" -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 - #ifndef SOL_XDP #define SOL_XDP 283 #endif -- cgit v1.2.3 From 22dd1ac91a77675238d10059c479ab6fa6160c60 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 18 Aug 2020 18:36:07 -0700 Subject: tools: Remove feature-libelf-mmap feature detection It's trivial to handle missing ELF_C_MMAP_READ support in libelf the way that objtool has solved it in ("774bec3fddcc objtool: Add fallback from ELF_C_READ_MMAP to ELF_C_READ"). So instead of having an entire feature detector for that, just do what objtool does for perf and libbpf. And keep their Makefiles a bit simpler. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200819013607.3607269-5-andriin@fb.com --- tools/lib/bpf/Makefile | 6 +----- tools/lib/bpf/libbpf.c | 14 ++++++-------- 2 files changed, 7 insertions(+), 13 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 621ad96d06fd..c5dbfafdf889 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -56,7 +56,7 @@ ifndef VERBOSE endif FEATURE_USER = .libbpf -FEATURE_TESTS = libelf libelf-mmap zlib bpf +FEATURE_TESTS = libelf zlib bpf FEATURE_DISPLAY = libelf zlib bpf INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi @@ -98,10 +98,6 @@ else CFLAGS := -g -Wall endif -ifeq ($(feature-libelf-mmap), 1) - override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT -endif - # Append required CFLAGS override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum override CFLAGS += -Werror -Wall diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4b96e0eefea8..4a81c6b2d21b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -150,12 +150,6 @@ static void pr_perm_msg(int err) ___err; }) #endif -#ifdef HAVE_LIBELF_MMAP_SUPPORT -# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP -#else -# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ -#endif - static inline __u64 ptr_to_u64(const void *ptr) { return (__u64) (unsigned long) ptr; @@ -1064,6 +1058,11 @@ static void bpf_object__elf_finish(struct bpf_object *obj) obj->efile.obj_buf_sz = 0; } +/* if libelf is old and doesn't support mmap(), fall back to read() */ +#ifndef ELF_C_READ_MMAP +#define ELF_C_READ_MMAP ELF_C_READ +#endif + static int bpf_object__elf_init(struct bpf_object *obj) { int err = 0; @@ -1092,8 +1091,7 @@ static int bpf_object__elf_init(struct bpf_object *obj) return err; } - obj->efile.elf = elf_begin(obj->efile.fd, - LIBBPF_ELF_C_READ_MMAP, NULL); + obj->efile.elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL); } if (!obj->efile.elf) { -- cgit v1.2.3 From 3fc32f40c40207bf85ce1b007f18981c4673df96 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 19 Aug 2020 12:45:15 -0700 Subject: libbpf: Implement type-based CO-RE relocations support Implement support for TYPE_EXISTS/TYPE_SIZE/TYPE_ID_LOCAL/TYPE_ID_REMOTE relocations. These are examples of type-based relocations, as opposed to field-based relocations supported already. The difference is that they are calculating relocation values based on the type itself, not a field within a struct/union. Type-based relos have slightly different semantics when matching local types to kernel target types, see comments in bpf_core_types_are_compat() for details. Their behavior on failure to find target type in kernel BTF also differs. Instead of "poisoning" relocatable instruction and failing load subsequently in kernel, they return 0 (which is rarely a valid return result, so user BPF code can use that to detect success/failure of the relocation and deal with it without extra "guarding" relocations). Also, it's always possible to check existence of the type in target kernel with TYPE_EXISTS relocation, similarly to a field-based FIELD_EXISTS. TYPE_ID_LOCAL relocation is a bit special in that it always succeeds (barring any libbpf/Clang bugs) and resolved to BTF ID using **local** BTF info of BPF program itself. Tests in subsequent patches demonstrate the usage and semantics of new relocations. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200819194519.3375898-2-andriin@fb.com --- tools/lib/bpf/bpf_core_read.h | 52 ++++++++- tools/lib/bpf/libbpf.c | 231 ++++++++++++++++++++++++++++++++++++---- tools/lib/bpf/libbpf_internal.h | 4 + 3 files changed, 263 insertions(+), 24 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 03152cb143b7..684bfb86361a 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -19,6 +19,18 @@ enum bpf_field_info_kind { BPF_FIELD_RSHIFT_U64 = 5, }; +/* second argument to __builtin_btf_type_id() built-in */ +enum bpf_type_id_kind { + BPF_TYPE_ID_LOCAL = 0, /* BTF type ID in local program */ + BPF_TYPE_ID_TARGET = 1, /* BTF type ID in target kernel */ +}; + +/* second argument to __builtin_preserve_type_info() built-in */ +enum bpf_type_info_kind { + BPF_TYPE_EXISTS = 0, /* type existence in target kernel */ + BPF_TYPE_SIZE = 1, /* type size in target kernel */ +}; + #define __CORE_RELO(src, field, info) \ __builtin_preserve_field_info((src)->field, BPF_FIELD_##info) @@ -94,12 +106,50 @@ enum bpf_field_info_kind { __builtin_preserve_field_info(field, BPF_FIELD_EXISTS) /* - * Convenience macro to get byte size of a field. Works for integers, + * Convenience macro to get the byte size of a field. Works for integers, * struct/unions, pointers, arrays, and enums. */ #define bpf_core_field_size(field) \ __builtin_preserve_field_info(field, BPF_FIELD_BYTE_SIZE) +/* + * Convenience macro to get BTF type ID of a specified type, using a local BTF + * information. Return 32-bit unsigned integer with type ID from program's own + * BTF. Always succeeds. + */ +#define bpf_core_type_id_local(type) \ + __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_LOCAL) + +/* + * Convenience macro to get BTF type ID of a target kernel's type that matches + * specified local type. + * Returns: + * - valid 32-bit unsigned type ID in kernel BTF; + * - 0, if no matching type was found in a target kernel BTF. + */ +#define bpf_core_type_id_kernel(type) \ + __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_TARGET) + +/* + * Convenience macro to check that provided named type + * (struct/union/enum/typedef) exists in a target kernel. + * Returns: + * 1, if such type is present in target kernel's BTF; + * 0, if no matching type is found. + */ +#define bpf_core_type_exists(type) \ + __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_EXISTS) + +/* + * Convenience macro to get the byte size of a provided named type + * (struct/union/enum/typedef) in a target kernel. + * Returns: + * >= 0 size (in bytes), if type is present in target kernel's BTF; + * 0, if no matching type is found. + */ +#define bpf_core_type_size(type) \ + __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_SIZE) + /* * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures * offset relocation for source address using __builtin_preserve_access_index() diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4a81c6b2d21b..882759dfc33e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4111,6 +4111,10 @@ static const char *core_relo_kind_str(enum bpf_core_relo_kind kind) case BPF_FIELD_SIGNED: return "signed"; case BPF_FIELD_LSHIFT_U64: return "lshift_u64"; case BPF_FIELD_RSHIFT_U64: return "rshift_u64"; + case BPF_TYPE_ID_LOCAL: return "local_type_id"; + case BPF_TYPE_ID_TARGET: return "target_type_id"; + case BPF_TYPE_EXISTS: return "type_exists"; + case BPF_TYPE_SIZE: return "type_size"; default: return "unknown"; } } @@ -4130,6 +4134,19 @@ static bool core_relo_is_field_based(enum bpf_core_relo_kind kind) } } +static bool core_relo_is_type_based(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_TYPE_ID_LOCAL: + case BPF_TYPE_ID_TARGET: + case BPF_TYPE_EXISTS: + case BPF_TYPE_SIZE: + return true; + default: + return false; + } +} + /* * Turn bpf_core_relo into a low- and high-level spec representation, * validating correctness along the way, as well as calculating resulting @@ -4160,6 +4177,9 @@ static bool core_relo_is_field_based(enum bpf_core_relo_kind kind) * - field 'a' access (corresponds to '2' in low-level spec); * - array element #3 access (corresponds to '3' in low-level spec). * + * Type-based relocations (TYPE_EXISTS/TYPE_SIZE, + * TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their + * spec and raw_spec are kept empty. */ static int bpf_core_parse_spec(const struct btf *btf, __u32 type_id, @@ -4182,6 +4202,13 @@ static int bpf_core_parse_spec(const struct btf *btf, spec->root_type_id = type_id; spec->relo_kind = relo_kind; + /* type-based relocations don't have a field access string */ + if (core_relo_is_type_based(relo_kind)) { + if (strcmp(spec_str, "0")) + return -EINVAL; + return 0; + } + /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */ while (*spec_str) { if (*spec_str == ':') @@ -4317,7 +4344,7 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, const struct btf *targ_btf) { size_t local_essent_len, targ_essent_len; - const char *local_name, *targ_name, *targ_kind; + const char *local_name, *targ_name; const struct btf_type *t, *local_t; struct ids_vec *cand_ids; __u32 *new_ids; @@ -4339,13 +4366,11 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, n = btf__get_nr_types(targ_btf); for (i = 1; i <= n; i++) { t = btf__type_by_id(targ_btf, i); - targ_name = btf__name_by_offset(targ_btf, t->name_off); - if (str_is_empty(targ_name)) + if (btf_kind(t) != btf_kind(local_t)) continue; - targ_kind = btf_kind_str(t); - t = skip_mods_and_typedefs(targ_btf, i, NULL); - if (!btf_is_composite(t) && !btf_is_array(t)) + targ_name = btf__name_by_offset(targ_btf, t->name_off); + if (str_is_empty(targ_name)) continue; targ_essent_len = bpf_core_essential_name_len(targ_name); @@ -4355,7 +4380,7 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, if (strncmp(local_name, targ_name, local_essent_len) == 0) { pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n", local_type_id, btf_kind_str(local_t), - local_name, i, targ_kind, targ_name); + local_name, i, btf_kind_str(t), targ_name); new_ids = libbpf_reallocarray(cand_ids->data, cand_ids->len + 1, sizeof(*cand_ids->data)); @@ -4373,8 +4398,9 @@ err_out: return ERR_PTR(err); } -/* Check two types for compatibility, skipping const/volatile/restrict and - * typedefs, to ensure we are relocating compatible entities: +/* Check two types for compatibility for the purpose of field access + * relocation. const/volatile/restrict and typedefs are skipped to ensure we + * are relocating semantically compatible entities: * - any two STRUCTs/UNIONs are compatible and can be mixed; * - any two FWDs are compatible, if their names match (modulo flavor suffix); * - any two PTRs are always compatible; @@ -4529,6 +4555,100 @@ static int bpf_core_match_member(const struct btf *local_btf, return 0; } +/* Check local and target types for compatibility. This check is used for + * type-based CO-RE relocations and follow slightly different rules than + * field-based relocations. This function assumes that root types were already + * checked for name match. Beyond that initial root-level name check, names + * are completely ignored. Compatibility rules are as follows: + * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but + * kind should match for local and target types (i.e., STRUCT is not + * compatible with UNION); + * - for ENUMs, the size is ignored; + * - for INT, size and signedness are ignored; + * - for ARRAY, dimensionality is ignored, element types are checked for + * compatibility recursively; + * - CONST/VOLATILE/RESTRICT modifiers are ignored; + * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible; + * - FUNC_PROTOs are compatible if they have compatible signature: same + * number of input args and compatible return and argument types. + * These rules are not set in stone and probably will be adjusted as we get + * more experience with using BPF CO-RE relocations. + */ +static int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) +{ + const struct btf_type *local_type, *targ_type; + int depth = 32; /* max recursion depth */ + + /* caller made sure that names match (ignoring flavor suffix) */ + local_type = btf__type_by_id(local_btf, local_id); + targ_type = btf__type_by_id(local_btf, local_id); + if (btf_kind(local_type) != btf_kind(targ_type)) + return 0; + +recur: + depth--; + if (depth < 0) + return -EINVAL; + + local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id); + targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); + if (!local_type || !targ_type) + return -EINVAL; + + if (btf_kind(local_type) != btf_kind(targ_type)) + return 0; + + switch (btf_kind(local_type)) { + case BTF_KIND_UNKN: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_ENUM: + case BTF_KIND_FWD: + return 1; + case BTF_KIND_INT: + /* just reject deprecated bitfield-like integers; all other + * integers are by default compatible between each other + */ + return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0; + case BTF_KIND_PTR: + local_id = local_type->type; + targ_id = targ_type->type; + goto recur; + case BTF_KIND_ARRAY: + local_id = btf_array(local_type)->type; + targ_id = btf_array(targ_type)->type; + goto recur; + case BTF_KIND_FUNC_PROTO: { + struct btf_param *local_p = btf_params(local_type); + struct btf_param *targ_p = btf_params(targ_type); + __u16 local_vlen = btf_vlen(local_type); + __u16 targ_vlen = btf_vlen(targ_type); + int i, err; + + if (local_vlen != targ_vlen) + return 0; + + for (i = 0; i < local_vlen; i++, local_p++, targ_p++) { + skip_mods_and_typedefs(local_btf, local_p->type, &local_id); + skip_mods_and_typedefs(targ_btf, targ_p->type, &targ_id); + err = bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id); + if (err <= 0) + return err; + } + + /* tail recurse for return type check */ + skip_mods_and_typedefs(local_btf, local_type->type, &local_id); + skip_mods_and_typedefs(targ_btf, targ_type->type, &targ_id); + goto recur; + } + default: + pr_warn("unexpected kind %s relocated, local [%d], target [%d]\n", + btf_kind_str(local_type), local_id, targ_id); + return 0; + } +} + /* * Try to match local spec to a target type and, if successful, produce full * target spec (high-level, low-level + bit offset). @@ -4547,6 +4667,12 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec, targ_spec->root_type_id = targ_id; targ_spec->relo_kind = local_spec->relo_kind; + if (core_relo_is_type_based(local_spec->relo_kind)) { + return bpf_core_types_are_compat(local_spec->btf, + local_spec->root_type_id, + targ_btf, targ_id); + } + local_acc = &local_spec->spec[0]; targ_acc = &targ_spec->spec[0]; @@ -4720,6 +4846,40 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, return 0; } +static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo, + const struct bpf_core_spec *spec, + __u32 *val) +{ + __s64 sz; + + /* type-based relos return zero when target type is not found */ + if (!spec) { + *val = 0; + return 0; + } + + switch (relo->kind) { + case BPF_TYPE_ID_TARGET: + *val = spec->root_type_id; + break; + case BPF_TYPE_EXISTS: + *val = 1; + break; + case BPF_TYPE_SIZE: + sz = btf__resolve_size(spec->btf, spec->root_type_id); + if (sz < 0) + return -EINVAL; + *val = sz; + break; + case BPF_TYPE_ID_LOCAL: + /* BPF_TYPE_ID_LOCAL is handled specially and shouldn't get here */ + default: + return -EOPNOTSUPP; + } + + return 0; +} + struct bpf_core_relo_res { /* expected value in the instruction, unless validate == false */ @@ -4755,6 +4915,9 @@ static int bpf_core_calc_relo(const struct bpf_program *prog, if (core_relo_is_field_based(relo->kind)) { err = bpf_core_calc_field_relo(prog, relo, local_spec, &res->orig_val, &res->validate); err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec, &res->new_val, NULL); + } else if (core_relo_is_type_based(relo->kind)) { + err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val); + err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val); } if (err == -EUCLEAN) { @@ -4894,6 +5057,9 @@ static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "" : s); + if (core_relo_is_type_based(spec->relo_kind)) + return; + if (core_relo_is_field_based(spec->relo_kind)) { for (i = 0; i < spec->len; i++) { if (spec->spec[i].name) @@ -4911,6 +5077,7 @@ static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) spec->bit_offset / 8, spec->bit_offset % 8); else libbpf_print(level, " @ offset %u)", spec->bit_offset / 8); + return; } } @@ -4979,12 +5146,12 @@ static void *u32_as_hash_key(__u32 x) * between multiple relocations for the same type ID and is updated as some * of the candidates are pruned due to structural incompatibility. */ -static int bpf_core_reloc_field(struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct btf *local_btf, - const struct btf *targ_btf, - struct hashmap *cand_cache) +static int bpf_core_apply_relo(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + const struct btf *targ_btf, + struct hashmap *cand_cache) { const char *prog_name = bpf_program__title(prog, false); struct bpf_core_spec local_spec, cand_spec, targ_spec; @@ -5003,7 +5170,7 @@ static int bpf_core_reloc_field(struct bpf_program *prog, return -EINVAL; local_name = btf__name_by_offset(local_btf, local_type->name_off); - if (str_is_empty(local_name)) + if (!local_name) return -EINVAL; spec_str = btf__name_by_offset(local_btf, relo->access_str_off); @@ -5014,7 +5181,8 @@ static int bpf_core_reloc_field(struct bpf_program *prog, if (err) { pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n", prog_name, relo_idx, local_id, btf_kind_str(local_type), - local_name, spec_str, err); + str_is_empty(local_name) ? "" : local_name, + spec_str, err); return -EINVAL; } @@ -5023,12 +5191,28 @@ static int bpf_core_reloc_field(struct bpf_program *prog, bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec); libbpf_print(LIBBPF_DEBUG, "\n"); + /* TYPE_ID_LOCAL relo is special and doesn't need candidate search */ + if (relo->kind == BPF_TYPE_ID_LOCAL) { + targ_res.validate = true; + targ_res.poison = false; + targ_res.orig_val = local_spec.root_type_id; + targ_res.new_val = local_spec.root_type_id; + goto patch_insn; + } + + /* libbpf doesn't support candidate search for anonymous types */ + if (str_is_empty(spec_str)) { + pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n", + prog_name, relo_idx, core_relo_kind_str(relo->kind), relo->kind); + return -EOPNOTSUPP; + } + if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) { cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf); if (IS_ERR(cand_ids)) { pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld", - prog_name, relo_idx, local_id, btf_kind_str(local_type), local_name, - PTR_ERR(cand_ids)); + prog_name, relo_idx, local_id, btf_kind_str(local_type), + local_name, PTR_ERR(cand_ids)); return PTR_ERR(cand_ids); } err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL); @@ -5084,7 +5268,7 @@ static int bpf_core_reloc_field(struct bpf_program *prog, return -EINVAL; } - cand_ids->data[j++] = cand_spec.spec[0].type_id; + cand_ids->data[j++] = cand_spec.root_type_id; } /* @@ -5103,7 +5287,7 @@ static int bpf_core_reloc_field(struct bpf_program *prog, * as well as expected case, depending whether instruction w/ * relocation is guarded in some way that makes it unreachable (dead * code) if relocation can't be resolved. This is handled in - * bpf_core_reloc_insn() uniformly by replacing that instruction with + * bpf_core_patch_insn() uniformly by replacing that instruction with * BPF helper call insn (using invalid helper ID). If that instruction * is indeed unreachable, then it will be ignored and eliminated by * verifier. If it was an error, then verifier will complain and point @@ -5119,6 +5303,7 @@ static int bpf_core_reloc_field(struct bpf_program *prog, return err; } +patch_insn: /* bpf_core_patch_insn() should know how to handle missing targ_spec */ err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res); if (err) { @@ -5186,8 +5371,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) sec_name, sec->num_info); for_each_btf_ext_rec(seg, sec, i, rec) { - err = bpf_core_reloc_field(prog, rec, i, obj->btf, - targ_btf, cand_cache); + err = bpf_core_apply_relo(prog, rec, i, obj->btf, + targ_btf, cand_cache); if (err) { pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", sec_name, i, err); diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index c8ed352671d5..edd3511aa242 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -238,6 +238,10 @@ enum bpf_core_relo_kind { BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */ BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */ BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */ + BPF_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */ + BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */ + BPF_TYPE_EXISTS = 8, /* type existence in target kernel */ + BPF_TYPE_SIZE = 9, /* type size in bytes */ }; /* The minimum bpf_core_relo checked by the loader -- cgit v1.2.3 From eacaaed784e2c9da69dea3030c81062c1fd66a37 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 19 Aug 2020 12:45:18 -0700 Subject: libbpf: Implement enum value-based CO-RE relocations Implement two relocations of a new enumerator value-based CO-RE relocation kind: ENUMVAL_EXISTS and ENUMVAL_VALUE. First, ENUMVAL_EXISTS, allows to detect the presence of a named enumerator value in the target (kernel) BTF. This is useful to do BPF helper/map/program type support detection from BPF program side. bpf_core_enum_value_exists() macro helper is provided to simplify built-in usage. Second, ENUMVAL_VALUE, allows to capture enumerator integer value and relocate it according to the target BTF, if it changes. This is useful to have a guarantee against intentional or accidental re-ordering/re-numbering of some of the internal (non-UAPI) enumerations, where kernel developers don't care about UAPI backwards compatiblity concerns. bpf_core_enum_value() allows to capture this succinctly and use correct enum values in code. LLVM uses ldimm64 instruction to capture enumerator value-based relocations, so add support for ldimm64 instruction patching as well. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200819194519.3375898-5-andriin@fb.com --- tools/lib/bpf/bpf_core_read.h | 28 ++++++++ tools/lib/bpf/libbpf.c | 145 ++++++++++++++++++++++++++++++++++++++-- tools/lib/bpf/libbpf_internal.h | 2 + 3 files changed, 170 insertions(+), 5 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 684bfb86361a..bbcefb3ff5a5 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -31,6 +31,12 @@ enum bpf_type_info_kind { BPF_TYPE_SIZE = 1, /* type size in target kernel */ }; +/* second argument to __builtin_preserve_enum_value() built-in */ +enum bpf_enum_value_kind { + BPF_ENUMVAL_EXISTS = 0, /* enum value existence in kernel */ + BPF_ENUMVAL_VALUE = 1, /* enum value value relocation */ +}; + #define __CORE_RELO(src, field, info) \ __builtin_preserve_field_info((src)->field, BPF_FIELD_##info) @@ -150,6 +156,28 @@ enum bpf_type_info_kind { #define bpf_core_type_size(type) \ __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_SIZE) +/* + * Convenience macro to check that provided enumerator value is defined in + * a target kernel. + * Returns: + * 1, if specified enum type and its enumerator value are present in target + * kernel's BTF; + * 0, if no matching enum and/or enum value within that enum is found. + */ +#define bpf_core_enum_value_exists(enum_type, enum_value) \ + __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS) + +/* + * Convenience macro to get the integer value of an enumerator value in + * a target kernel. + * Returns: + * 64-bit value, if specified enum type and its enumerator value are + * present in target kernel's BTF; + * 0, if no matching enum and/or enum value within that enum is found. + */ +#define bpf_core_enum_value(enum_type, enum_value) \ + __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_VALUE) + /* * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures * offset relocation for source address using __builtin_preserve_access_index() diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 882759dfc33e..77d420c02094 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4115,6 +4115,8 @@ static const char *core_relo_kind_str(enum bpf_core_relo_kind kind) case BPF_TYPE_ID_TARGET: return "target_type_id"; case BPF_TYPE_EXISTS: return "type_exists"; case BPF_TYPE_SIZE: return "type_size"; + case BPF_ENUMVAL_EXISTS: return "enumval_exists"; + case BPF_ENUMVAL_VALUE: return "enumval_value"; default: return "unknown"; } } @@ -4147,6 +4149,17 @@ static bool core_relo_is_type_based(enum bpf_core_relo_kind kind) } } +static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_ENUMVAL_EXISTS: + case BPF_ENUMVAL_VALUE: + return true; + default: + return false; + } +} + /* * Turn bpf_core_relo into a low- and high-level spec representation, * validating correctness along the way, as well as calculating resulting @@ -4180,6 +4193,9 @@ static bool core_relo_is_type_based(enum bpf_core_relo_kind kind) * Type-based relocations (TYPE_EXISTS/TYPE_SIZE, * TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their * spec and raw_spec are kept empty. + * + * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access + * string to specify enumerator's value index that need to be relocated. */ static int bpf_core_parse_spec(const struct btf *btf, __u32 type_id, @@ -4224,16 +4240,25 @@ static int bpf_core_parse_spec(const struct btf *btf, if (spec->raw_len == 0) return -EINVAL; - /* first spec value is always reloc type array index */ t = skip_mods_and_typedefs(btf, type_id, &id); if (!t) return -EINVAL; access_idx = spec->raw_spec[0]; - spec->spec[0].type_id = id; - spec->spec[0].idx = access_idx; + acc = &spec->spec[0]; + acc->type_id = id; + acc->idx = access_idx; spec->len++; + if (core_relo_is_enumval_based(relo_kind)) { + if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t)) + return -EINVAL; + + /* record enumerator name in a first accessor */ + acc->name = btf__name_by_offset(btf, btf_enum(t)[access_idx].name_off); + return 0; + } + if (!core_relo_is_field_based(relo_kind)) return -EINVAL; @@ -4676,6 +4701,39 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec, local_acc = &local_spec->spec[0]; targ_acc = &targ_spec->spec[0]; + if (core_relo_is_enumval_based(local_spec->relo_kind)) { + size_t local_essent_len, targ_essent_len; + const struct btf_enum *e; + const char *targ_name; + + /* has to resolve to an enum */ + targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id); + if (!btf_is_enum(targ_type)) + return 0; + + local_essent_len = bpf_core_essential_name_len(local_acc->name); + + for (i = 0, e = btf_enum(targ_type); i < btf_vlen(targ_type); i++, e++) { + targ_name = btf__name_by_offset(targ_spec->btf, e->name_off); + targ_essent_len = bpf_core_essential_name_len(targ_name); + if (targ_essent_len != local_essent_len) + continue; + if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) { + targ_acc->type_id = targ_id; + targ_acc->idx = i; + targ_acc->name = targ_name; + targ_spec->len++; + targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx; + targ_spec->raw_len++; + return 1; + } + } + return 0; + } + + if (!core_relo_is_field_based(local_spec->relo_kind)) + return -EINVAL; + for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) { targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id); @@ -4880,6 +4938,31 @@ static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo, return 0; } +static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo, + const struct bpf_core_spec *spec, + __u32 *val) +{ + const struct btf_type *t; + const struct btf_enum *e; + + switch (relo->kind) { + case BPF_ENUMVAL_EXISTS: + *val = spec ? 1 : 0; + break; + case BPF_ENUMVAL_VALUE: + if (!spec) + return -EUCLEAN; /* request instruction poisoning */ + t = btf__type_by_id(spec->btf, spec->spec[0].type_id); + e = btf_enum(t) + spec->spec[0].idx; + *val = e->val; + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + struct bpf_core_relo_res { /* expected value in the instruction, unless validate == false */ @@ -4918,6 +5001,9 @@ static int bpf_core_calc_relo(const struct bpf_program *prog, } else if (core_relo_is_type_based(relo->kind)) { err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val); err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val); + } else if (core_relo_is_enumval_based(relo->kind)) { + err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val); + err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val); } if (err == -EUCLEAN) { @@ -4954,6 +5040,11 @@ static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */ } +static bool is_ldimm64(struct bpf_insn *insn) +{ + return insn->code == (BPF_LD | BPF_IMM | BPF_DW); +} + /* * Patch relocatable BPF instruction. * @@ -4966,6 +5057,7 @@ static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, * Currently three kinds of BPF instructions are supported: * 1. rX = (assignment with immediate operand); * 2. rX += (arithmetic operations with immediate operand); + * 3. rX = (load with 64-bit immediate value). */ static int bpf_core_patch_insn(struct bpf_program *prog, const struct bpf_core_relo *relo, @@ -4984,6 +5076,11 @@ static int bpf_core_patch_insn(struct bpf_program *prog, class = BPF_CLASS(insn->code); if (res->poison) { + /* poison second part of ldimm64 to avoid confusing error from + * verifier about "unknown opcode 00" + */ + if (is_ldimm64(insn)) + bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1); bpf_core_poison_insn(prog, relo_idx, insn_idx, insn); return 0; } @@ -5012,7 +5109,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog, case BPF_ST: case BPF_STX: if (res->validate && insn->off != orig_val) { - pr_warn("prog '%s': relo #%d: unexpected insn #%d (LD/LDX/ST/STX) value: got %u, exp %u -> %u\n", + pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n", bpf_program__title(prog, false), relo_idx, insn_idx, insn->off, orig_val, new_val); return -EINVAL; @@ -5029,8 +5126,36 @@ static int bpf_core_patch_insn(struct bpf_program *prog, bpf_program__title(prog, false), relo_idx, insn_idx, orig_val, new_val); break; + case BPF_LD: { + __u64 imm; + + if (!is_ldimm64(insn) || + insn[0].src_reg != 0 || insn[0].off != 0 || + insn_idx + 1 >= prog->insns_cnt || + insn[1].code != 0 || insn[1].dst_reg != 0 || + insn[1].src_reg != 0 || insn[1].off != 0) { + pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n", + bpf_program__title(prog, false), relo_idx, insn_idx); + return -EINVAL; + } + + imm = insn[0].imm + ((__u64)insn[1].imm << 32); + if (res->validate && imm != orig_val) { + pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n", + bpf_program__title(prog, false), relo_idx, + insn_idx, imm, orig_val, new_val); + return -EINVAL; + } + + insn[0].imm = new_val; + insn[1].imm = 0; /* currently only 32-bit values are supported */ + pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n", + bpf_program__title(prog, false), relo_idx, insn_idx, + imm, new_val); + break; + } default: - pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n", + pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n", bpf_program__title(prog, false), relo_idx, insn_idx, insn->code, insn->src_reg, insn->dst_reg, insn->off, insn->imm); @@ -5047,6 +5172,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog, static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) { const struct btf_type *t; + const struct btf_enum *e; const char *s; __u32 type_id; int i; @@ -5060,6 +5186,15 @@ static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) if (core_relo_is_type_based(spec->relo_kind)) return; + if (core_relo_is_enumval_based(spec->relo_kind)) { + t = skip_mods_and_typedefs(spec->btf, type_id, NULL); + e = btf_enum(t) + spec->raw_spec[0]; + s = btf__name_by_offset(spec->btf, e->name_off); + + libbpf_print(level, "::%s = %u", s, e->val); + return; + } + if (core_relo_is_field_based(spec->relo_kind)) { for (i = 0; i < spec->len; i++) { if (spec->spec[i].name) diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index edd3511aa242..61dff515a2f0 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -242,6 +242,8 @@ enum bpf_core_relo_kind { BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */ BPF_TYPE_EXISTS = 8, /* type existence in target kernel */ BPF_TYPE_SIZE = 9, /* type size in bytes */ + BPF_ENUMVAL_EXISTS = 10, /* enum value existence in target kernel */ + BPF_ENUMVAL_VALUE = 11, /* enum value integer value */ }; /* The minimum bpf_core_relo checked by the loader -- cgit v1.2.3 From 6e9cab2e3fa597419ec8a117a9f3e3ebc251c120 Mon Sep 17 00:00:00 2001 From: Xu Wang Date: Wed, 19 Aug 2020 02:53:24 +0000 Subject: libbpf: Simplify the return expression of build_map_pin_path() Simplify the return expression. Signed-off-by: Xu Wang Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200819025324.14680-1-vulab@iscas.ac.cn --- tools/lib/bpf/libbpf.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 77d420c02094..829d62a3ad5f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1943,7 +1943,7 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, static int build_map_pin_path(struct bpf_map *map, const char *path) { char buf[PATH_MAX]; - int err, len; + int len; if (!path) path = "/sys/fs/bpf"; @@ -1954,11 +1954,7 @@ static int build_map_pin_path(struct bpf_map *map, const char *path) else if (len >= PATH_MAX) return -ENAMETOOLONG; - err = bpf_map__set_pin_path(map, buf); - if (err) - return err; - - return 0; + return bpf_map__set_pin_path(map, buf); } -- cgit v1.2.3 From d71fa5c9763c24dd997a2fa4feb7a13a95bab42c Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 18 Aug 2020 21:27:58 -0700 Subject: bpf: Add kernel module with user mode driver that populates bpffs. Add kernel module with user mode driver that populates bpffs with BPF iterators. $ mount bpffs /my/bpffs/ -t bpf $ ls -la /my/bpffs/ total 4 drwxrwxrwt 2 root root 0 Jul 2 00:27 . drwxr-xr-x 19 root root 4096 Jul 2 00:09 .. -rw------- 1 root root 0 Jul 2 00:27 maps.debug -rw------- 1 root root 0 Jul 2 00:27 progs.debug The user mode driver will load BPF Type Formats, create BPF maps, populate BPF maps, load two BPF programs, attach them to BPF iterators, and finally send two bpf_link IDs back to the kernel. The kernel will pin two bpf_links into newly mounted bpffs instance under names "progs.debug" and "maps.debug". These two files become human readable. $ cat /my/bpffs/progs.debug id name attached 11 dump_bpf_map bpf_iter_bpf_map 12 dump_bpf_prog bpf_iter_bpf_prog 27 test_pkt_access 32 test_main test_pkt_access test_pkt_access 33 test_subprog1 test_pkt_access_subprog1 test_pkt_access 34 test_subprog2 test_pkt_access_subprog2 test_pkt_access 35 test_subprog3 test_pkt_access_subprog3 test_pkt_access 36 new_get_skb_len get_skb_len test_pkt_access 37 new_get_skb_ifindex get_skb_ifindex test_pkt_access 38 new_get_constant get_constant test_pkt_access The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about all BPF programs currently loaded in the system. This information is unstable and will change from kernel to kernel as ".debug" suffix conveys. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com --- tools/lib/bpf/Makefile | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index c5dbfafdf889..66b2cfadf262 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -1,6 +1,9 @@ # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) # Most of this file is copied from tools/lib/traceevent/Makefile +RM ?= rm +srctree = $(abs_srctree) + LIBBPF_VERSION := $(shell \ grep -oE '^LIBBPF_([0-9.]+)' libbpf.map | \ sort -rV | head -n1 | cut -d'_' -f2) @@ -188,7 +191,7 @@ $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED) @ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION) $(OUTPUT)libbpf.a: $(BPF_IN_STATIC) - $(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^ + $(QUIET_LINK)$(RM) -f $@; $(AR) rcs $@ $^ $(OUTPUT)libbpf.pc: $(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \ @@ -291,7 +294,7 @@ cscope: cscope -b -q -I $(srctree)/include -f cscope.out tags: - rm -f TAGS tags + $(RM) -f TAGS tags ls *.c *.h | xargs $(TAGS_PROG) -a # Declare the contents of the .PHONY variable as phony. We keep that -- cgit v1.2.3 From 9b2f6fecf3b77d2457a13f77a563c07304f15775 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 19 Aug 2020 23:14:08 -0700 Subject: libbpf: Fix detection of BPF helper call instruction BPF_CALL | BPF_JMP32 is explicitly not allowed by verifier for BPF helper calls, so don't detect it as a valid call. Also drop the check on func_id pointer, as it's currently always non-null. Fixes: 109cea5a594f ("libbpf: Sanitize BPF program code for bpf_probe_read_{kernel, user}[_str]") Reported-by: Yonghong Song Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200820061411.1755905-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 829d62a3ad5f..0bc1fd813408 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5840,14 +5840,12 @@ static int bpf_object__collect_reloc(struct bpf_object *obj) static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id) { - __u8 class = BPF_CLASS(insn->code); - - if ((class == BPF_JMP || class == BPF_JMP32) && + if (BPF_CLASS(insn->code) == BPF_JMP && BPF_OP(insn->code) == BPF_CALL && BPF_SRC(insn->code) == BPF_K && - insn->src_reg == 0 && insn->dst_reg == 0) { - if (func_id) - *func_id = insn->imm; + insn->src_reg == 0 && + insn->dst_reg == 0) { + *func_id = insn->imm; return true; } return false; -- cgit v1.2.3 From dda1ec9fc7f8383cb469a82614dbce61f357f3f8 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 19 Aug 2020 23:14:09 -0700 Subject: libbpf: Fix libbpf build on compilers missing __builtin_mul_overflow GCC compilers older than version 5 don't support __builtin_mul_overflow yet. Given GCC 4.9 is the minimal supported compiler for building kernel and the fact that libbpf is a dependency of resolve_btfids, which is dependency of CONFIG_DEBUG_INFO_BTF=y, this needs to be handled. This patch fixes the issue by falling back to slower detection of integer overflow in such cases. Fixes: 029258d7b228 ("libbpf: Remove any use of reallocarray() in libbpf") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200820061411.1755905-2-andriin@fb.com --- tools/lib/bpf/libbpf_internal.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 61dff515a2f0..4d1c366fca2c 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -10,6 +10,7 @@ #define __LIBBPF_LIBBPF_INTERNAL_H #include +#include /* make sure libbpf doesn't use kernel-only integer typedefs */ #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 @@ -77,6 +78,9 @@ do { \ #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) +#ifndef __has_builtin +#define __has_builtin(x) 0 +#endif /* * Re-implement glibc's reallocarray() for libbpf internal-only use. * reallocarray(), unfortunately, is not available in all versions of glibc, @@ -90,8 +94,14 @@ static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) { size_t total; +#if __has_builtin(__builtin_mul_overflow) if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) return NULL; +#else + if (size == 0 || nmemb > ULONG_MAX / size) + return NULL; + total = nmemb * size; +#endif return realloc(ptr, total); } -- cgit v1.2.3 From dca5612f8eb9d0cf1dc254eb2adff1f16a588a7d Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 21 Aug 2020 09:59:27 -0700 Subject: libbpf: Add perf_buffer APIs for better integration with outside epoll loop Add a set of APIs to perf_buffer manage to allow applications to integrate perf buffer polling into existing epoll-based infrastructure. One example is applications using libevent already and wanting to plug perf_buffer polling, instead of relying on perf_buffer__poll() and waste an extra thread to do it. But perf_buffer is still extremely useful to set up and consume perf buffer rings even for such use cases. So to accomodate such new use cases, add three new APIs: - perf_buffer__buffer_cnt() returns number of per-CPU buffers maintained by given instance of perf_buffer manager; - perf_buffer__buffer_fd() returns FD of perf_event corresponding to a specified per-CPU buffer; this FD is then polled independently; - perf_buffer__consume_buffer() consumes data from single per-CPU buffer, identified by its slot index. To support a simpler, but less efficient, way to integrate perf_buffer into external polling logic, also expose underlying epoll FD through perf_buffer__epoll_fd() API. It will need to be followed by perf_buffer__poll(), wasting extra syscall, or perf_buffer__consume(), wasting CPU to iterate buffers with no data. But could be simpler and more convenient for some cases. These APIs allow for great flexiblity, but do not sacrifice general usability of perf_buffer. Also exercise and check new APIs in perf_buffer selftest. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Reviewed-by: Alan Maguire Link: https://lore.kernel.org/bpf/20200821165927.849538-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++- tools/lib/bpf/libbpf.h | 4 ++++ tools/lib/bpf/libbpf.map | 8 +++++++ 3 files changed, 67 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0bc1fd813408..210429c5b772 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9373,6 +9373,11 @@ static int perf_buffer__process_records(struct perf_buffer *pb, return 0; } +int perf_buffer__epoll_fd(const struct perf_buffer *pb) +{ + return pb->epoll_fd; +} + int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms) { int i, cnt, err; @@ -9390,6 +9395,55 @@ int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms) return cnt < 0 ? -errno : cnt; } +/* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer + * manager. + */ +size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb) +{ + return pb->cpu_cnt; +} + +/* + * Return perf_event FD of a ring buffer in *buf_idx* slot of + * PERF_EVENT_ARRAY BPF map. This FD can be polled for new data using + * select()/poll()/epoll() Linux syscalls. + */ +int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx) +{ + struct perf_cpu_buf *cpu_buf; + + if (buf_idx >= pb->cpu_cnt) + return -EINVAL; + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return -ENOENT; + + return cpu_buf->fd; +} + +/* + * Consume data from perf ring buffer corresponding to slot *buf_idx* in + * PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to + * consume, do nothing and return success. + * Returns: + * - 0 on success; + * - <0 on failure. + */ +int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx) +{ + struct perf_cpu_buf *cpu_buf; + + if (buf_idx >= pb->cpu_cnt) + return -EINVAL; + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return -ENOENT; + + return perf_buffer__process_records(pb, cpu_buf); +} + int perf_buffer__consume(struct perf_buffer *pb) { int i, err; @@ -9402,7 +9456,7 @@ int perf_buffer__consume(struct perf_buffer *pb) err = perf_buffer__process_records(pb, cpu_buf); if (err) { - pr_warn("error while processing records: %d\n", err); + pr_warn("perf_buffer: failed to process records in buffer #%d: %d\n", i, err); return err; } } diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 5ecb4069a9f0..308e0ded8f14 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -588,8 +588,12 @@ perf_buffer__new_raw(int map_fd, size_t page_cnt, const struct perf_buffer_raw_opts *opts); LIBBPF_API void perf_buffer__free(struct perf_buffer *pb); +LIBBPF_API int perf_buffer__epoll_fd(const struct perf_buffer *pb); LIBBPF_API int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms); LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb); +LIBBPF_API int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx); +LIBBPF_API size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb); +LIBBPF_API int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx); typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr, diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index e35bd6cdbdbf..66a6286d0716 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -299,3 +299,11 @@ LIBBPF_0.1.0 { btf__set_fd; btf__set_pointer_size; } LIBBPF_0.0.9; + +LIBBPF_0.2.0 { + global: + perf_buffer__buffer_cnt; + perf_buffer__buffer_fd; + perf_buffer__epoll_fd; + perf_buffer__consume_buffer; +} LIBBPF_0.1.0; -- cgit v1.2.3 From 88a82120282bdef4c331e20991e3057f417beae4 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 20 Aug 2020 16:12:36 -0700 Subject: libbpf: Factor out common ELF operations and improve logging Factor out common ELF operations done throughout the libbpf. This simplifies usage across multiple places in libbpf, as well as hide error reporting from higher-level functions and make error logging more consistent. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200820231250.1293069-3-andriin@fb.com --- tools/lib/bpf/libbpf.c | 367 +++++++++++++++++++++++++++---------------------- 1 file changed, 206 insertions(+), 161 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 210429c5b772..dfb18d3ee590 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -398,6 +398,7 @@ struct bpf_object { Elf_Data *rodata; Elf_Data *bss; Elf_Data *st_ops_data; + size_t shstrndx; /* section index for section name strings */ size_t strtabidx; struct { GElf_Shdr shdr; @@ -435,6 +436,14 @@ struct bpf_object { }; #define obj_elf_valid(o) ((o)->efile.elf) +static const char *elf_sym_str(const struct bpf_object *obj, size_t off); +static const char *elf_sec_str(const struct bpf_object *obj, size_t off); +static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx); +static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name); +static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr); +static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn); +static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn); + void bpf_program__unload(struct bpf_program *prog) { int i; @@ -496,7 +505,7 @@ static char *__bpf_program__pin_name(struct bpf_program *prog) } static int -bpf_program__init(void *data, size_t size, char *section_name, int idx, +bpf_program__init(void *data, size_t size, const char *section_name, int idx, struct bpf_program *prog) { const size_t bpf_insn_sz = sizeof(struct bpf_insn); @@ -545,7 +554,7 @@ errout: static int bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, - char *section_name, int idx) + const char *section_name, int idx) { struct bpf_program prog, *progs; int nr_progs, err; @@ -570,7 +579,7 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, return -ENOMEM; } - pr_debug("found program %s\n", prog.section_name); + pr_debug("elf: found program '%s'\n", prog.section_name); obj->programs = progs; obj->nr_programs = nr_progs + 1; prog.obj = obj; @@ -590,8 +599,7 @@ bpf_object__init_prog_names(struct bpf_object *obj) prog = &obj->programs[pi]; - for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name; - si++) { + for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name; si++) { GElf_Sym sym; if (!gelf_getsym(symbols, si, &sym)) @@ -601,11 +609,9 @@ bpf_object__init_prog_names(struct bpf_object *obj) if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL) continue; - name = elf_strptr(obj->efile.elf, - obj->efile.strtabidx, - sym.st_name); + name = elf_sym_str(obj, sym.st_name); if (!name) { - pr_warn("failed to get sym name string for prog %s\n", + pr_warn("prog '%s': failed to get symbol name\n", prog->section_name); return -LIBBPF_ERRNO__LIBELF; } @@ -615,17 +621,14 @@ bpf_object__init_prog_names(struct bpf_object *obj) name = ".text"; if (!name) { - pr_warn("failed to find sym for prog %s\n", + pr_warn("prog '%s': failed to find program symbol\n", prog->section_name); return -EINVAL; } prog->name = strdup(name); - if (!prog->name) { - pr_warn("failed to allocate memory for prog sym %s\n", - name); + if (!prog->name) return -ENOMEM; - } } return 0; @@ -1069,7 +1072,7 @@ static int bpf_object__elf_init(struct bpf_object *obj) GElf_Ehdr *ep; if (obj_elf_valid(obj)) { - pr_warn("elf init: internal error\n"); + pr_warn("elf: init internal error\n"); return -LIBBPF_ERRNO__LIBELF; } @@ -1087,7 +1090,7 @@ static int bpf_object__elf_init(struct bpf_object *obj) err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); - pr_warn("failed to open %s: %s\n", obj->path, cp); + pr_warn("elf: failed to open %s: %s\n", obj->path, cp); return err; } @@ -1095,22 +1098,36 @@ static int bpf_object__elf_init(struct bpf_object *obj) } if (!obj->efile.elf) { - pr_warn("failed to open %s as ELF file\n", obj->path); + pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__LIBELF; goto errout; } if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) { - pr_warn("failed to get EHDR from %s\n", obj->path); + pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__FORMAT; goto errout; } ep = &obj->efile.ehdr; + if (elf_getshdrstrndx(obj->efile.elf, &obj->efile.shstrndx)) { + pr_warn("elf: failed to get section names section index for %s: %s\n", + obj->path, elf_errmsg(-1)); + err = -LIBBPF_ERRNO__FORMAT; + goto errout; + } + + /* Elf is corrupted/truncated, avoid calling elf_strptr. */ + if (!elf_rawdata(elf_getscn(obj->efile.elf, obj->efile.shstrndx), NULL)) { + pr_warn("elf: failed to get section names strings from %s: %s\n", + obj->path, elf_errmsg(-1)); + return -LIBBPF_ERRNO__FORMAT; + } + /* Old LLVM set e_machine to EM_NONE */ if (ep->e_type != ET_REL || (ep->e_machine && ep->e_machine != EM_BPF)) { - pr_warn("%s is not an eBPF object file\n", obj->path); + pr_warn("elf: %s is not a valid eBPF object file\n", obj->path); err = -LIBBPF_ERRNO__FORMAT; goto errout; } @@ -1132,7 +1149,7 @@ static int bpf_object__check_endianness(struct bpf_object *obj) #else # error "Unrecognized __BYTE_ORDER__" #endif - pr_warn("endianness mismatch.\n"); + pr_warn("elf: endianness mismatch in %s.\n", obj->path); return -LIBBPF_ERRNO__ENDIAN; } @@ -1167,55 +1184,10 @@ static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) return false; } -static int bpf_object_search_section_size(const struct bpf_object *obj, - const char *name, size_t *d_size) -{ - const GElf_Ehdr *ep = &obj->efile.ehdr; - Elf *elf = obj->efile.elf; - Elf_Scn *scn = NULL; - int idx = 0; - - while ((scn = elf_nextscn(elf, scn)) != NULL) { - const char *sec_name; - Elf_Data *data; - GElf_Shdr sh; - - idx++; - if (gelf_getshdr(scn, &sh) != &sh) { - pr_warn("failed to get section(%d) header from %s\n", - idx, obj->path); - return -EIO; - } - - sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name); - if (!sec_name) { - pr_warn("failed to get section(%d) name from %s\n", - idx, obj->path); - return -EIO; - } - - if (strcmp(name, sec_name)) - continue; - - data = elf_getdata(scn, 0); - if (!data) { - pr_warn("failed to get section(%d) data from %s(%s)\n", - idx, name, obj->path); - return -EIO; - } - - *d_size = data->d_size; - return 0; - } - - return -ENOENT; -} - int bpf_object__section_size(const struct bpf_object *obj, const char *name, __u32 *size) { int ret = -ENOENT; - size_t d_size; *size = 0; if (!name) { @@ -1233,9 +1205,13 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name, if (obj->efile.st_ops_data) *size = obj->efile.st_ops_data->d_size; } else { - ret = bpf_object_search_section_size(obj, name, &d_size); - if (!ret) - *size = d_size; + Elf_Scn *scn = elf_sec_by_name(obj, name); + Elf_Data *data = elf_sec_data(obj, scn); + + if (data) { + ret = 0; /* found it */ + *size = data->d_size; + } } return *size ? 0 : ret; @@ -1260,8 +1236,7 @@ int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, GELF_ST_TYPE(sym.st_info) != STT_OBJECT) continue; - sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx, - sym.st_name); + sname = elf_sym_str(obj, sym.st_name); if (!sname) { pr_warn("failed to get sym name string for var %s\n", name); @@ -1738,12 +1713,12 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) if (!symbols) return -EINVAL; - scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx); - if (scn) - data = elf_getdata(scn, NULL); + + scn = elf_sec_by_idx(obj, obj->efile.maps_shndx); + data = elf_sec_data(obj, scn); if (!scn || !data) { - pr_warn("failed to get Elf_Data from map section %d\n", - obj->efile.maps_shndx); + pr_warn("elf: failed to get legacy map definitions for %s\n", + obj->path); return -EINVAL; } @@ -1765,12 +1740,12 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) nr_maps++; } /* Assume equally sized map definitions */ - pr_debug("maps in %s: %d maps in %zd bytes\n", - obj->path, nr_maps, data->d_size); + pr_debug("elf: found %d legacy map definitions (%zd bytes) in %s\n", + nr_maps, data->d_size, obj->path); if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) { - pr_warn("unable to determine map definition size section %s, %d maps in %zd bytes\n", - obj->path, nr_maps, data->d_size); + pr_warn("elf: unable to determine legacy map definition size in %s\n", + obj->path); return -EINVAL; } map_def_sz = data->d_size / nr_maps; @@ -1791,8 +1766,7 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) if (IS_ERR(map)) return PTR_ERR(map); - map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, - sym.st_name); + map_name = elf_sym_str(obj, sym.st_name); if (!map_name) { pr_warn("failed to get map #%d name sym string for obj %s\n", i, obj->path); @@ -2274,12 +2248,11 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, if (obj->efile.btf_maps_shndx < 0) return 0; - scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx); - if (scn) - data = elf_getdata(scn, NULL); + scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx); + data = elf_sec_data(obj, scn); if (!scn || !data) { - pr_warn("failed to get Elf_Data from map section %d (%s)\n", - obj->efile.maps_shndx, MAPS_ELF_SEC); + pr_warn("elf: failed to get %s map definitions for %s\n", + MAPS_ELF_SEC, obj->path); return -EINVAL; } @@ -2337,20 +2310,12 @@ static int bpf_object__init_maps(struct bpf_object *obj, static bool section_have_execinstr(struct bpf_object *obj, int idx) { - Elf_Scn *scn; GElf_Shdr sh; - scn = elf_getscn(obj->efile.elf, idx); - if (!scn) - return false; - - if (gelf_getshdr(scn, &sh) != &sh) + if (elf_sec_hdr(obj, elf_sec_by_idx(obj, idx), &sh)) return false; - if (sh.sh_flags & SHF_EXECINSTR) - return true; - - return false; + return sh.sh_flags & SHF_EXECINSTR; } static bool btf_needs_sanitization(struct bpf_object *obj) @@ -2594,61 +2559,156 @@ report: return err; } +static const char *elf_sym_str(const struct bpf_object *obj, size_t off) +{ + const char *name; + + name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, off); + if (!name) { + pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n", + off, obj->path, elf_errmsg(-1)); + return NULL; + } + + return name; +} + +static const char *elf_sec_str(const struct bpf_object *obj, size_t off) +{ + const char *name; + + name = elf_strptr(obj->efile.elf, obj->efile.shstrndx, off); + if (!name) { + pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n", + off, obj->path, elf_errmsg(-1)); + return NULL; + } + + return name; +} + +static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx) +{ + Elf_Scn *scn; + + scn = elf_getscn(obj->efile.elf, idx); + if (!scn) { + pr_warn("elf: failed to get section(%zu) from %s: %s\n", + idx, obj->path, elf_errmsg(-1)); + return NULL; + } + return scn; +} + +static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name) +{ + Elf_Scn *scn = NULL; + Elf *elf = obj->efile.elf; + const char *sec_name; + + while ((scn = elf_nextscn(elf, scn)) != NULL) { + sec_name = elf_sec_name(obj, scn); + if (!sec_name) + return NULL; + + if (strcmp(sec_name, name) != 0) + continue; + + return scn; + } + return NULL; +} + +static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr) +{ + if (!scn) + return -EINVAL; + + if (gelf_getshdr(scn, hdr) != hdr) { + pr_warn("elf: failed to get section(%zu) header from %s: %s\n", + elf_ndxscn(scn), obj->path, elf_errmsg(-1)); + return -EINVAL; + } + + return 0; +} + +static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn) +{ + const char *name; + GElf_Shdr sh; + + if (!scn) + return NULL; + + if (elf_sec_hdr(obj, scn, &sh)) + return NULL; + + name = elf_sec_str(obj, sh.sh_name); + if (!name) { + pr_warn("elf: failed to get section(%zu) name from %s: %s\n", + elf_ndxscn(scn), obj->path, elf_errmsg(-1)); + return NULL; + } + + return name; +} + +static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) +{ + Elf_Data *data; + + if (!scn) + return NULL; + + data = elf_getdata(scn, 0); + if (!data) { + pr_warn("elf: failed to get section(%zu) %s data from %s: %s\n", + elf_ndxscn(scn), elf_sec_name(obj, scn) ?: "", + obj->path, elf_errmsg(-1)); + return NULL; + } + + return data; +} + static int bpf_object__elf_collect(struct bpf_object *obj) { Elf *elf = obj->efile.elf; - GElf_Ehdr *ep = &obj->efile.ehdr; Elf_Data *btf_ext_data = NULL; Elf_Data *btf_data = NULL; Elf_Scn *scn = NULL; int idx = 0, err = 0; - /* Elf is corrupted/truncated, avoid calling elf_strptr. */ - if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) { - pr_warn("failed to get e_shstrndx from %s\n", obj->path); - return -LIBBPF_ERRNO__FORMAT; - } - while ((scn = elf_nextscn(elf, scn)) != NULL) { - char *name; + const char *name; GElf_Shdr sh; Elf_Data *data; idx++; - if (gelf_getshdr(scn, &sh) != &sh) { - pr_warn("failed to get section(%d) header from %s\n", - idx, obj->path); + + if (elf_sec_hdr(obj, scn, &sh)) return -LIBBPF_ERRNO__FORMAT; - } - name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name); - if (!name) { - pr_warn("failed to get section(%d) name from %s\n", - idx, obj->path); + name = elf_sec_str(obj, sh.sh_name); + if (!name) return -LIBBPF_ERRNO__FORMAT; - } - data = elf_getdata(scn, 0); - if (!data) { - pr_warn("failed to get section(%d) data from %s(%s)\n", - idx, name, obj->path); + data = elf_sec_data(obj, scn); + if (!data) return -LIBBPF_ERRNO__FORMAT; - } - pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n", + + pr_debug("elf: section(%d) %s, size %ld, link %d, flags %lx, type=%d\n", idx, name, (unsigned long)data->d_size, (int)sh.sh_link, (unsigned long)sh.sh_flags, (int)sh.sh_type); if (strcmp(name, "license") == 0) { - err = bpf_object__init_license(obj, - data->d_buf, - data->d_size); + err = bpf_object__init_license(obj, data->d_buf, data->d_size); if (err) return err; } else if (strcmp(name, "version") == 0) { - err = bpf_object__init_kversion(obj, - data->d_buf, - data->d_size); + err = bpf_object__init_kversion(obj, data->d_buf, data->d_size); if (err) return err; } else if (strcmp(name, "maps") == 0) { @@ -2661,8 +2721,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) btf_ext_data = data; } else if (sh.sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { - pr_warn("bpf: multiple SYMTAB in %s\n", - obj->path); + pr_warn("elf: multiple symbol tables in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } obj->efile.symbols = data; @@ -2675,16 +2734,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) err = bpf_object__add_program(obj, data->d_buf, data->d_size, name, idx); - if (err) { - char errmsg[STRERR_BUFSIZE]; - char *cp; - - cp = libbpf_strerror_r(-err, errmsg, - sizeof(errmsg)); - pr_warn("failed to alloc program %s (%s): %s", - name, obj->path, cp); + if (err) return err; - } } else if (strcmp(name, DATA_SEC) == 0) { obj->efile.data = data; obj->efile.data_shndx = idx; @@ -2695,7 +2746,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) obj->efile.st_ops_data = data; obj->efile.st_ops_shndx = idx; } else { - pr_debug("skip section(%d) %s\n", idx, name); + pr_debug("elf: skipping unrecognized data section(%d) %s\n", + idx, name); } } else if (sh.sh_type == SHT_REL) { int nr_sects = obj->efile.nr_reloc_sects; @@ -2706,34 +2758,32 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (!section_have_execinstr(obj, sec) && strcmp(name, ".rel" STRUCT_OPS_SEC) && strcmp(name, ".rel" MAPS_ELF_SEC)) { - pr_debug("skip relo %s(%d) for section(%d)\n", - name, idx, sec); + pr_debug("elf: skipping relo section(%d) %s for section(%d) %s\n", + idx, name, sec, + elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: ""); continue; } sects = libbpf_reallocarray(sects, nr_sects + 1, sizeof(*obj->efile.reloc_sects)); - if (!sects) { - pr_warn("reloc_sects realloc failed\n"); + if (!sects) return -ENOMEM; - } obj->efile.reloc_sects = sects; obj->efile.nr_reloc_sects++; obj->efile.reloc_sects[nr_sects].shdr = sh; obj->efile.reloc_sects[nr_sects].data = data; - } else if (sh.sh_type == SHT_NOBITS && - strcmp(name, BSS_SEC) == 0) { + } else if (sh.sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) { obj->efile.bss = data; obj->efile.bss_shndx = idx; } else { - pr_debug("skip section(%d) %s\n", idx, name); + pr_debug("elf: skipping section(%d) %s\n", idx, name); } } if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) { - pr_warn("Corrupted ELF file: index of strtab invalid\n"); + pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } return bpf_object__init_btf(obj, btf_data, btf_ext_data); @@ -2894,14 +2944,13 @@ static int bpf_object__collect_externs(struct bpf_object *obj) if (!obj->efile.symbols) return 0; - scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx); - if (!scn) - return -LIBBPF_ERRNO__FORMAT; - if (gelf_getshdr(scn, &sh) != &sh) + scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx); + if (elf_sec_hdr(obj, scn, &sh)) return -LIBBPF_ERRNO__FORMAT; - n = sh.sh_size / sh.sh_entsize; + n = sh.sh_size / sh.sh_entsize; pr_debug("looking for externs among %d symbols...\n", n); + for (i = 0; i < n; i++) { GElf_Sym sym; @@ -2909,8 +2958,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj) return -LIBBPF_ERRNO__FORMAT; if (!sym_is_extern(&sym)) continue; - ext_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, - sym.st_name); + ext_name = elf_sym_str(obj, sym.st_name); if (!ext_name || !ext_name[0]) continue; @@ -3289,16 +3337,15 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, return -LIBBPF_ERRNO__FORMAT; } if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { - pr_warn("relocation: symbol %"PRIx64" not found\n", - GELF_R_SYM(rel.r_info)); + pr_warn("relocation: symbol %zx not found\n", + (size_t)GELF_R_SYM(rel.r_info)); return -LIBBPF_ERRNO__FORMAT; } if (rel.r_offset % sizeof(struct bpf_insn)) return -LIBBPF_ERRNO__FORMAT; insn_idx = rel.r_offset / sizeof(struct bpf_insn); - name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, - sym.st_name) ? : ""; + name = elf_sym_str(obj, sym.st_name) ?: ""; pr_debug("relo for shdr %u, symb %zu, value %zu, type %d, bind %d, name %d (\'%s\'), insn %u\n", (__u32)sym.st_shndx, (size_t)GELF_R_SYM(rel.r_info), @@ -5720,8 +5767,7 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, i, (size_t)GELF_R_SYM(rel.r_info)); return -LIBBPF_ERRNO__FORMAT; } - name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, - sym.st_name) ? : ""; + name = elf_sym_str(obj, sym.st_name) ?: ""; if (sym.st_shndx != obj->efile.btf_maps_shndx) { pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n", i, name); @@ -7663,8 +7709,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, return -LIBBPF_ERRNO__FORMAT; } - name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, - sym.st_name) ? : ""; + name = elf_sym_str(obj, sym.st_name) ?: ""; map = find_struct_ops_map_by_offset(obj, rel.r_offset); if (!map) { pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n", -- cgit v1.2.3 From 819c23af561c4dc8c35faaacacdfa9ba81bacf5f Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 20 Aug 2020 16:12:37 -0700 Subject: libbpf: Add __noinline macro to bpf_helpers.h __noinline is pretty frequently used, especially with BPF subprograms, so add them along the __always_inline, for user convenience and completeness. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200820231250.1293069-4-andriin@fb.com --- tools/lib/bpf/bpf_helpers.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index e9a4ecddb7a5..1106777df00b 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -32,6 +32,9 @@ #ifndef __always_inline #define __always_inline __attribute__((always_inline)) #endif +#ifndef __noinline +#define __noinline __attribute__((noinline)) +#endif #ifndef __weak #define __weak __attribute__((weak)) #endif -- cgit v1.2.3 From 50e09460d9f8dee9fbaaa3194c7921753d75cd96 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 20 Aug 2020 16:12:38 -0700 Subject: libbpf: Skip well-known ELF sections when iterating ELF Skip and don't log ELF sections that libbpf knows about and ignores during ELF processing. This allows to not unnecessarily log details about those ELF sections and cleans up libbpf debug log. Ignored sections include DWARF data, string table, empty .text section and few special (e.g., .llvm_addrsig) useless sections. With such ELF sections out of the way, log unrecognized ELF sections at pr_info level to increase visibility. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200820231250.1293069-5-andriin@fb.com --- tools/lib/bpf/libbpf.c | 55 ++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 49 insertions(+), 6 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index dfb18d3ee590..2ae89b84a2be 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2672,6 +2672,46 @@ static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) return data; } +static bool is_sec_name_dwarf(const char *name) +{ + /* approximation, but the actual list is too long */ + return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0; +} + +static bool ignore_elf_section(GElf_Shdr *hdr, const char *name) +{ + /* no special handling of .strtab */ + if (hdr->sh_type == SHT_STRTAB) + return true; + + /* ignore .llvm_addrsig section as well */ + if (hdr->sh_type == 0x6FFF4C03 /* SHT_LLVM_ADDRSIG */) + return true; + + /* no subprograms will lead to an empty .text section, ignore it */ + if (hdr->sh_type == SHT_PROGBITS && hdr->sh_size == 0 && + strcmp(name, ".text") == 0) + return true; + + /* DWARF sections */ + if (is_sec_name_dwarf(name)) + return true; + + if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) { + name += sizeof(".rel") - 1; + /* DWARF section relocations */ + if (is_sec_name_dwarf(name)) + return true; + + /* .BTF and .BTF.ext don't need relocations */ + if (strcmp(name, BTF_ELF_SEC) == 0 || + strcmp(name, BTF_EXT_ELF_SEC) == 0) + return true; + } + + return false; +} + static int bpf_object__elf_collect(struct bpf_object *obj) { Elf *elf = obj->efile.elf; @@ -2694,6 +2734,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (!name) return -LIBBPF_ERRNO__FORMAT; + if (ignore_elf_section(&sh, name)) + continue; + data = elf_sec_data(obj, scn); if (!data) return -LIBBPF_ERRNO__FORMAT; @@ -2746,8 +2789,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) obj->efile.st_ops_data = data; obj->efile.st_ops_shndx = idx; } else { - pr_debug("elf: skipping unrecognized data section(%d) %s\n", - idx, name); + pr_info("elf: skipping unrecognized data section(%d) %s\n", + idx, name); } } else if (sh.sh_type == SHT_REL) { int nr_sects = obj->efile.nr_reloc_sects; @@ -2758,9 +2801,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (!section_have_execinstr(obj, sec) && strcmp(name, ".rel" STRUCT_OPS_SEC) && strcmp(name, ".rel" MAPS_ELF_SEC)) { - pr_debug("elf: skipping relo section(%d) %s for section(%d) %s\n", - idx, name, sec, - elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: ""); + pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", + idx, name, sec, + elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: ""); continue; } @@ -2778,7 +2821,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) obj->efile.bss = data; obj->efile.bss_shndx = idx; } else { - pr_debug("elf: skipping section(%d) %s\n", idx, name); + pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, sh.sh_size); } } -- cgit v1.2.3 From 9c0f8cbdc0e9cf8a2a3a96045778b8d759f172c2 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 20 Aug 2020 16:12:39 -0700 Subject: libbpf: Normalize and improve logging across few functions Make libbpf logs follow similar pattern and provide more context like section name or program name, where appropriate. Also, add BPF_INSN_SZ constant and use it throughout to clean up code a little bit. This commit doesn't have any functional changes and just removes some code changes out of the way before bigger refactoring in libbpf internals. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200820231250.1293069-6-andriin@fb.com --- tools/lib/bpf/libbpf.c | 117 ++++++++++++++++++++++++++++--------------------- 1 file changed, 67 insertions(+), 50 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2ae89b84a2be..fb7b8fb1d3fa 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -63,6 +63,8 @@ #define BPF_FS_MAGIC 0xcafe4a11 #endif +#define BPF_INSN_SZ (sizeof(struct bpf_insn)) + /* vsprintf() in __base_pr() uses nonliteral format string. It may break * compilation if user enables corresponding warning. Disable it explicitly. */ @@ -3225,7 +3227,7 @@ bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx) static int bpf_program__record_reloc(struct bpf_program *prog, struct reloc_desc *reloc_desc, - __u32 insn_idx, const char *name, + __u32 insn_idx, const char *sym_name, const GElf_Sym *sym, const GElf_Rel *rel) { struct bpf_insn *insn = &prog->insns[insn_idx]; @@ -3233,22 +3235,25 @@ static int bpf_program__record_reloc(struct bpf_program *prog, struct bpf_object *obj = prog->obj; __u32 shdr_idx = sym->st_shndx; enum libbpf_map_type type; + const char *sym_sec_name; struct bpf_map *map; /* sub-program call relocation */ if (insn->code == (BPF_JMP | BPF_CALL)) { if (insn->src_reg != BPF_PSEUDO_CALL) { - pr_warn("incorrect bpf_call opcode\n"); + pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name); return -LIBBPF_ERRNO__RELOC; } /* text_shndx can be 0, if no default "main" program exists */ if (!shdr_idx || shdr_idx != obj->efile.text_shndx) { - pr_warn("bad call relo against section %u\n", shdr_idx); + sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); + pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n", + prog->name, sym_name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } - if (sym->st_value % 8) { - pr_warn("bad call relo offset: %zu\n", - (size_t)sym->st_value); + if (sym->st_value % BPF_INSN_SZ) { + pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n", + prog->name, sym_name, (size_t)sym->st_value); return -LIBBPF_ERRNO__RELOC; } reloc_desc->type = RELO_CALL; @@ -3259,8 +3264,8 @@ static int bpf_program__record_reloc(struct bpf_program *prog, } if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) { - pr_warn("invalid relo for insns[%d].code 0x%x\n", - insn_idx, insn->code); + pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n", + prog->name, sym_name, insn_idx, insn->code); return -LIBBPF_ERRNO__RELOC; } @@ -3275,12 +3280,12 @@ static int bpf_program__record_reloc(struct bpf_program *prog, break; } if (i >= n) { - pr_warn("extern relo failed to find extern for sym %d\n", - sym_idx); + pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n", + prog->name, sym_name, sym_idx); return -LIBBPF_ERRNO__RELOC; } - pr_debug("found extern #%d '%s' (sym %d) for insn %u\n", - i, ext->name, ext->sym_idx, insn_idx); + pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n", + prog->name, i, ext->name, ext->sym_idx, insn_idx); reloc_desc->type = RELO_EXTERN; reloc_desc->insn_idx = insn_idx; reloc_desc->sym_off = i; /* sym_off stores extern index */ @@ -3288,18 +3293,19 @@ static int bpf_program__record_reloc(struct bpf_program *prog, } if (!shdr_idx || shdr_idx >= SHN_LORESERVE) { - pr_warn("invalid relo for \'%s\' in special section 0x%x; forgot to initialize global var?..\n", - name, shdr_idx); + pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n", + prog->name, sym_name, shdr_idx); return -LIBBPF_ERRNO__RELOC; } type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx); + sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); /* generic map reference relocation */ if (type == LIBBPF_MAP_UNSPEC) { if (!bpf_object__shndx_is_maps(obj, shdr_idx)) { - pr_warn("bad map relo against section %u\n", - shdr_idx); + pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n", + prog->name, sym_name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } for (map_idx = 0; map_idx < nr_maps; map_idx++) { @@ -3308,14 +3314,14 @@ static int bpf_program__record_reloc(struct bpf_program *prog, map->sec_idx != sym->st_shndx || map->sec_offset != sym->st_value) continue; - pr_debug("found map %zd (%s, sec %d, off %zu) for insn %u\n", - map_idx, map->name, map->sec_idx, + pr_debug("prog '%s': found map %zd (%s, sec %d, off %zu) for insn #%u\n", + prog->name, map_idx, map->name, map->sec_idx, map->sec_offset, insn_idx); break; } if (map_idx >= nr_maps) { - pr_warn("map relo failed to find map for sec %u, off %zu\n", - shdr_idx, (size_t)sym->st_value); + pr_warn("prog '%s': map relo failed to find map for section '%s', off %zu\n", + prog->name, sym_sec_name, (size_t)sym->st_value); return -LIBBPF_ERRNO__RELOC; } reloc_desc->type = RELO_LD64; @@ -3327,21 +3333,22 @@ static int bpf_program__record_reloc(struct bpf_program *prog, /* global data map relocation */ if (!bpf_object__shndx_is_data(obj, shdr_idx)) { - pr_warn("bad data relo against section %u\n", shdr_idx); + pr_warn("prog '%s': bad data relo against section '%s'\n", + prog->name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } for (map_idx = 0; map_idx < nr_maps; map_idx++) { map = &obj->maps[map_idx]; if (map->libbpf_type != type) continue; - pr_debug("found data map %zd (%s, sec %d, off %zu) for insn %u\n", - map_idx, map->name, map->sec_idx, map->sec_offset, - insn_idx); + pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n", + prog->name, map_idx, map->name, map->sec_idx, + map->sec_offset, insn_idx); break; } if (map_idx >= nr_maps) { - pr_warn("data relo failed to find map for sec %u\n", - shdr_idx); + pr_warn("prog '%s': data relo failed to find map for section '%s'\n", + prog->name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } @@ -3357,9 +3364,17 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, Elf_Data *data, struct bpf_object *obj) { Elf_Data *symbols = obj->efile.symbols; + const char *relo_sec_name, *sec_name; + size_t sec_idx = shdr->sh_info; int err, i, nrels; - pr_debug("collecting relocating info for: '%s'\n", prog->section_name); + relo_sec_name = elf_sec_str(obj, shdr->sh_name); + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + if (!relo_sec_name || !sec_name) + return -EINVAL; + + pr_debug("sec '%s': collecting relocation for section(%zu) '%s'\n", + relo_sec_name, sec_idx, sec_name); nrels = shdr->sh_size / shdr->sh_entsize; prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels); @@ -3370,34 +3385,34 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, prog->nr_reloc = nrels; for (i = 0; i < nrels; i++) { - const char *name; + const char *sym_name; __u32 insn_idx; GElf_Sym sym; GElf_Rel rel; if (!gelf_getrel(data, i, &rel)) { - pr_warn("relocation: failed to get %d reloc\n", i); + pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i); return -LIBBPF_ERRNO__FORMAT; } if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { - pr_warn("relocation: symbol %zx not found\n", - (size_t)GELF_R_SYM(rel.r_info)); + pr_warn("sec '%s': symbol 0x%zx not found for relo #%d\n", + relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); return -LIBBPF_ERRNO__FORMAT; } - if (rel.r_offset % sizeof(struct bpf_insn)) + if (rel.r_offset % BPF_INSN_SZ) { + pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n", + relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); return -LIBBPF_ERRNO__FORMAT; + } - insn_idx = rel.r_offset / sizeof(struct bpf_insn); - name = elf_sym_str(obj, sym.st_name) ?: ""; + insn_idx = rel.r_offset / BPF_INSN_SZ; + sym_name = elf_sym_str(obj, sym.st_name) ?: ""; - pr_debug("relo for shdr %u, symb %zu, value %zu, type %d, bind %d, name %d (\'%s\'), insn %u\n", - (__u32)sym.st_shndx, (size_t)GELF_R_SYM(rel.r_info), - (size_t)sym.st_value, GELF_ST_TYPE(sym.st_info), - GELF_ST_BIND(sym.st_info), sym.st_name, name, - insn_idx); + pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n", + relo_sec_name, i, insn_idx, sym_name); err = bpf_program__record_reloc(prog, &prog->reloc_desc[i], - insn_idx, name, &sym, &rel); + insn_idx, sym_name, &sym, &rel); if (err) return err; } @@ -5155,9 +5170,9 @@ static int bpf_core_patch_insn(struct bpf_program *prog, int insn_idx; __u8 class; - if (relo->insn_off % sizeof(struct bpf_insn)) + if (relo->insn_off % BPF_INSN_SZ) return -EINVAL; - insn_idx = relo->insn_off / sizeof(struct bpf_insn); + insn_idx = relo->insn_off / BPF_INSN_SZ; insn = &prog->insns[insn_idx]; class = BPF_CLASS(insn->code); @@ -5588,7 +5603,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) goto out; } - pr_debug("prog '%s': performing %d CO-RE offset relocs\n", + pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info); for_each_btf_ext_rec(seg, sec, i, rec) { @@ -5596,7 +5611,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) targ_btf, cand_cache); if (err) { pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", - sec_name, i, err); + prog->name, i, err); goto out; } } @@ -5716,7 +5731,8 @@ bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) return err; break; default: - pr_warn("relo #%d: bad relo type %d\n", i, relo->type); + pr_warn("prog '%s': relo #%d: bad relo type %d\n", + prog->name, i, relo->type); return -EINVAL; } } @@ -5751,7 +5767,8 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) err = bpf_program__relocate(prog, obj); if (err) { - pr_warn("failed to relocate '%s'\n", prog->section_name); + pr_warn("prog '%s': failed to relocate data references: %d\n", + prog->name, err); return err; } break; @@ -5766,7 +5783,8 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) err = bpf_program__relocate(prog, obj); if (err) { - pr_warn("failed to relocate '%s'\n", prog->section_name); + pr_warn("prog '%s': failed to relocate calls: %d\n", + prog->name, err); return err; } } @@ -6198,8 +6216,7 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level) if (bpf_program__is_function_storage(prog, obj)) continue; if (!prog->load) { - pr_debug("prog '%s'('%s'): skipped loading\n", - prog->name, prog->section_name); + pr_debug("prog '%s': skipped loading\n", prog->name); continue; } prog->log_level |= log_level; @@ -7343,7 +7360,7 @@ int bpf_program__fd(const struct bpf_program *prog) size_t bpf_program__size(const struct bpf_program *prog) { - return prog->insns_cnt * sizeof(struct bpf_insn); + return prog->insns_cnt * BPF_INSN_SZ; } int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, -- cgit v1.2.3 From 3418c56de81fd73f2265c8915f4b910bcc141cb7 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 21 Aug 2020 15:55:56 -0700 Subject: libbpf: Avoid false unuinitialized variable warning in bpf_core_apply_relo Some versions of GCC report uninitialized targ_spec usage. GCC is wrong, but let's avoid unnecessary warnings. Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200821225556.2178419-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index fb7b8fb1d3fa..cd4a2bba05ff 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5390,7 +5390,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, struct hashmap *cand_cache) { const char *prog_name = bpf_program__title(prog, false); - struct bpf_core_spec local_spec, cand_spec, targ_spec; + struct bpf_core_spec local_spec, cand_spec, targ_spec = {}; const void *type_key = u32_as_hash_key(relo->type_id); struct bpf_core_relo_res cand_res, targ_res; const struct btf_type *local_type; -- cgit v1.2.3 From f872e4bc47f100ccbbe9469cd12e5ac78e4b6eda Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 21 Aug 2020 15:56:53 -0700 Subject: libbpf: Fix type compatibility check copy-paste error Fix copy-paste error in types compatibility check. Local type is accidentally used instead of target type for the very first type check strictness check. This can result in potentially less strict candidate comparison. Fix the error. Fixes: 3fc32f40c402 ("libbpf: Implement type-based CO-RE relocations support") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200821225653.2180782-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index cd4a2bba05ff..2e2523d8bb6d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4708,7 +4708,7 @@ static int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id /* caller made sure that names match (ignoring flavor suffix) */ local_type = btf__type_by_id(local_btf, local_id); - targ_type = btf__type_by_id(local_btf, local_id); + targ_type = btf__type_by_id(targ_btf, targ_id); if (btf_kind(local_type) != btf_kind(targ_type)) return 0; -- cgit v1.2.3 From 8ea636848aca35b9f97c5b5dee30225cf2dd0fe6 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Tue, 25 Aug 2020 20:29:17 +0200 Subject: bpf: Implement bpf_local_storage for inodes Similar to bpf_local_storage for sockets, add local storage for inodes. The life-cycle of storage is managed with the life-cycle of the inode. i.e. the storage is destroyed along with the owning inode. The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the security blob which are now stackable and can co-exist with other LSMs. Signed-off-by: KP Singh Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200825182919.1118197-6-kpsingh@chromium.org --- tools/lib/bpf/libbpf_probes.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index 010c9a76fd2b..5482a9b7ae2d 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -170,7 +170,7 @@ int libbpf__load_raw_btf(const char *raw_types, size_t types_len, return btf_fd; } -static int load_sk_storage_btf(void) +static int load_local_storage_btf(void) { const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l"; /* struct bpf_spin_lock { @@ -229,12 +229,13 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex) key_size = 0; break; case BPF_MAP_TYPE_SK_STORAGE: + case BPF_MAP_TYPE_INODE_STORAGE: btf_key_type_id = 1; btf_value_type_id = 3; value_size = 8; max_entries = 0; map_flags = BPF_F_NO_PREALLOC; - btf_fd = load_sk_storage_btf(); + btf_fd = load_local_storage_btf(); if (btf_fd < 0) return false; break; -- cgit v1.2.3 From ef05afa66c59c2031a3798916ef3ff3778232129 Mon Sep 17 00:00:00 2001 From: Alex Gartrell Date: Wed, 26 Aug 2020 00:55:49 -0700 Subject: libbpf: Fix unintentional success return code in bpf_object__load There are code paths where EINVAL is returned directly without setting errno. In that case, errno could be 0, which would mask the failure. For example, if a careless programmer set log_level to 10000 out of laziness, they would have to spend a long time trying to figure out why. Fixes: 4f33ddb4e3e2 ("libbpf: Propagate EPERM to caller on program load") Signed-off-by: Alex Gartrell Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200826075549.1858580-1-alexgartrell@gmail.com --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2e2523d8bb6d..8f9e7d281225 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6067,7 +6067,7 @@ retry_load: free(log_buf); goto retry_load; } - ret = -errno; + ret = errno ? -errno : -LIBBPF_ERRNO__LOAD; cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warn("load bpf program failed: %s\n", cp); pr_perm_msg(ret); -- cgit v1.2.3 From 2e80be60c465a4f8559327340eaf40845dd7797a Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 26 Aug 2020 21:11:09 -0700 Subject: libbpf: Fix compilation warnings for 64-bit printf args Fix compilation warnings due to __u64 defined differently as `unsigned long` or `unsigned long long` on different architectures (e.g., ppc64le differs from x86-64). Also cast one argument to size_t to fix printf warning of similar nature. Fixes: eacaaed784e2 ("libbpf: Implement enum value-based CO-RE relocations") Fixes: 50e09460d9f8 ("libbpf: Skip well-known ELF sections when iterating ELF") Reported-by: Naresh Kamboju Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200827041109.3613090-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 8f9e7d281225..8cdb2528482e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2823,7 +2823,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) obj->efile.bss = data; obj->efile.bss_shndx = idx; } else { - pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, sh.sh_size); + pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, + (size_t)sh.sh_size); } } @@ -5244,7 +5245,8 @@ static int bpf_core_patch_insn(struct bpf_program *prog, if (res->validate && imm != orig_val) { pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n", bpf_program__title(prog, false), relo_idx, - insn_idx, imm, orig_val, new_val); + insn_idx, (unsigned long long)imm, + orig_val, new_val); return -EINVAL; } @@ -5252,7 +5254,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog, insn[1].imm = 0; /* currently only 32-bit values are supported */ pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n", bpf_program__title(prog, false), relo_idx, insn_idx, - imm, new_val); + (unsigned long long)imm, new_val); break; } default: -- cgit v1.2.3 From 661b37cd437ef49cd28444f79b9b0c71ea76e8c8 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Thu, 27 Aug 2020 10:53:36 +0200 Subject: tools, bpf/build: Cleanup feature files on make clean The system for "Auto-detecting system features" located under tools/build/ are (currently) used by perf, libbpf and bpftool. It can contain stalled feature detection files, which are not cleaned up by libbpf and bpftool on make clean (side-note: perf tool is correct). Fix this by making the users invoke the make clean target. Some details about the changes. The libbpf Makefile already had a clean-config target (which seems to be copy-pasted from perf), but this target was not "connected" (a make dependency) to clean target. Choose not to rename target as someone might be using it. Did change the output from "CLEAN config" to "CLEAN feature-detect", to make it more clear what happens. This is related to the complaint and troubleshooting in the following link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/ Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/ Link: https://lore.kernel.org/bpf/159851841661.1072907.13770213104521805592.stgit@firesoul --- tools/lib/bpf/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 66b2cfadf262..adbe994610f2 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -264,10 +264,10 @@ install: install_lib install_pkgconfig install_headers ### Cleaning rules config-clean: - $(call QUIET_CLEAN, config) + $(call QUIET_CLEAN, feature-detect) $(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null -clean: +clean: config-clean $(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \ *~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_HELPER_DEFS) \ $(SHARED_OBJDIR) $(STATIC_OBJDIR) \ -- cgit v1.2.3 From 2b288740a1072235166b2706e139f2725b5ea26f Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 27 Aug 2020 15:01:13 -0700 Subject: libbpf: Support sleepable progs Pass request to load program as sleepable via ".s" suffix in the section name. If it happens in the future that all map types and helpers are allowed with BPF_F_SLEEPABLE flag "fmod_ret/" and "lsm/" can be aliased to "fmod_ret.s/" and "lsm.s/" to make all lsm and fmod_ret programs sleepable by default. The fentry and fexit programs would always need to have sleepable vs non-sleepable distinction, since not all fentry/fexit progs will be attached to sleepable kernel functions. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: KP Singh Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200827220114.69225-5-alexei.starovoitov@gmail.com --- tools/lib/bpf/libbpf.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 8cdb2528482e..b688aadf09c5 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -208,6 +208,7 @@ struct bpf_sec_def { bool is_exp_attach_type_optional; bool is_attachable; bool is_attach_btf; + bool is_sleepable; attach_fn_t attach_fn; }; @@ -6291,6 +6292,8 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, /* couldn't guess, but user might manually specify */ continue; + if (prog->sec_def->is_sleepable) + prog->prog_flags |= BPF_F_SLEEPABLE; bpf_program__set_type(prog, prog->sec_def->prog_type); bpf_program__set_expected_attach_type(prog, prog->sec_def->expected_attach_type); @@ -7559,6 +7562,21 @@ static const struct bpf_sec_def section_defs[] = { .expected_attach_type = BPF_TRACE_FEXIT, .is_attach_btf = true, .attach_fn = attach_trace), + SEC_DEF("fentry.s/", TRACING, + .expected_attach_type = BPF_TRACE_FENTRY, + .is_attach_btf = true, + .is_sleepable = true, + .attach_fn = attach_trace), + SEC_DEF("fmod_ret.s/", TRACING, + .expected_attach_type = BPF_MODIFY_RETURN, + .is_attach_btf = true, + .is_sleepable = true, + .attach_fn = attach_trace), + SEC_DEF("fexit.s/", TRACING, + .expected_attach_type = BPF_TRACE_FEXIT, + .is_attach_btf = true, + .is_sleepable = true, + .attach_fn = attach_trace), SEC_DEF("freplace/", EXT, .is_attach_btf = true, .attach_fn = attach_trace), @@ -7566,6 +7584,11 @@ static const struct bpf_sec_def section_defs[] = { .is_attach_btf = true, .expected_attach_type = BPF_LSM_MAC, .attach_fn = attach_lsm), + SEC_DEF("lsm.s/", LSM, + .is_attach_btf = true, + .is_sleepable = true, + .expected_attach_type = BPF_LSM_MAC, + .attach_fn = attach_lsm), SEC_DEF("iter/", TRACING, .expected_attach_type = BPF_TRACE_ITER, .is_attach_btf = true, @@ -8288,7 +8311,7 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, prog->prog_ifindex = attr->ifindex; prog->log_level = attr->log_level; - prog->prog_flags = attr->prog_flags; + prog->prog_flags |= attr->prog_flags; if (!first_prog) first_prog = prog; } -- cgit v1.2.3 From 2f6324a3937f8517967d94daef2ba0bdceceece1 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Fri, 28 Aug 2020 10:26:27 +0200 Subject: libbpf: Support shared umems between queues and devices MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add support for shared umems between hardware queues and devices to the AF_XDP part of libbpf. This so that zero-copy can be achieved in applications that want to send and receive packets between HW queues on one device or between different devices/netdevs. In order to create sockets that share a umem between hardware queues and devices, a new function has been added called xsk_socket__create_shared(). It takes the same arguments as xsk_socket_create() plus references to a fill ring and a completion ring. So for every socket that share a umem, you need to have one more set of fill and completion rings. This in order to maintain the single-producer single-consumer semantics of the rings. You can create all the sockets via the new xsk_socket__create_shared() call, or create the first one with xsk_socket__create() and the rest with xsk_socket__create_shared(). Both methods work. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/1598603189-32145-14-git-send-email-magnus.karlsson@intel.com --- tools/lib/bpf/libbpf.map | 1 + tools/lib/bpf/xsk.c | 376 ++++++++++++++++++++++++++++++----------------- tools/lib/bpf/xsk.h | 9 ++ 3 files changed, 254 insertions(+), 132 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 66a6286d0716..3fedcdc4ae2f 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -306,4 +306,5 @@ LIBBPF_0.2.0 { perf_buffer__buffer_fd; perf_buffer__epoll_fd; perf_buffer__consume_buffer; + xsk_socket__create_shared; } LIBBPF_0.1.0; diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index a9b02103767b..49c324594792 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -45,26 +46,35 @@ #endif struct xsk_umem { - struct xsk_ring_prod *fill; - struct xsk_ring_cons *comp; + struct xsk_ring_prod *fill_save; + struct xsk_ring_cons *comp_save; char *umem_area; struct xsk_umem_config config; int fd; int refcount; + struct list_head ctx_list; +}; + +struct xsk_ctx { + struct xsk_ring_prod *fill; + struct xsk_ring_cons *comp; + __u32 queue_id; + struct xsk_umem *umem; + int refcount; + int ifindex; + struct list_head list; + int prog_fd; + int xsks_map_fd; + char ifname[IFNAMSIZ]; }; struct xsk_socket { struct xsk_ring_cons *rx; struct xsk_ring_prod *tx; __u64 outstanding_tx; - struct xsk_umem *umem; + struct xsk_ctx *ctx; struct xsk_socket_config config; int fd; - int ifindex; - int prog_fd; - int xsks_map_fd; - __u32 queue_id; - char ifname[IFNAMSIZ]; }; struct xsk_nl_info { @@ -200,15 +210,73 @@ static int xsk_get_mmap_offsets(int fd, struct xdp_mmap_offsets *off) return -EINVAL; } +static int xsk_create_umem_rings(struct xsk_umem *umem, int fd, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp) +{ + struct xdp_mmap_offsets off; + void *map; + int err; + + err = setsockopt(fd, SOL_XDP, XDP_UMEM_FILL_RING, + &umem->config.fill_size, + sizeof(umem->config.fill_size)); + if (err) + return -errno; + + err = setsockopt(fd, SOL_XDP, XDP_UMEM_COMPLETION_RING, + &umem->config.comp_size, + sizeof(umem->config.comp_size)); + if (err) + return -errno; + + err = xsk_get_mmap_offsets(fd, &off); + if (err) + return -errno; + + map = mmap(NULL, off.fr.desc + umem->config.fill_size * sizeof(__u64), + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, + XDP_UMEM_PGOFF_FILL_RING); + if (map == MAP_FAILED) + return -errno; + + fill->mask = umem->config.fill_size - 1; + fill->size = umem->config.fill_size; + fill->producer = map + off.fr.producer; + fill->consumer = map + off.fr.consumer; + fill->flags = map + off.fr.flags; + fill->ring = map + off.fr.desc; + fill->cached_cons = umem->config.fill_size; + + map = mmap(NULL, off.cr.desc + umem->config.comp_size * sizeof(__u64), + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, + XDP_UMEM_PGOFF_COMPLETION_RING); + if (map == MAP_FAILED) { + err = -errno; + goto out_mmap; + } + + comp->mask = umem->config.comp_size - 1; + comp->size = umem->config.comp_size; + comp->producer = map + off.cr.producer; + comp->consumer = map + off.cr.consumer; + comp->flags = map + off.cr.flags; + comp->ring = map + off.cr.desc; + + return 0; + +out_mmap: + munmap(map, off.fr.desc + umem->config.fill_size * sizeof(__u64)); + return err; +} + int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, __u64 size, struct xsk_ring_prod *fill, struct xsk_ring_cons *comp, const struct xsk_umem_config *usr_config) { - struct xdp_mmap_offsets off; struct xdp_umem_reg mr; struct xsk_umem *umem; - void *map; int err; if (!umem_area || !umem_ptr || !fill || !comp) @@ -227,6 +295,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, } umem->umem_area = umem_area; + INIT_LIST_HEAD(&umem->ctx_list); xsk_set_umem_config(&umem->config, usr_config); memset(&mr, 0, sizeof(mr)); @@ -241,71 +310,16 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, err = -errno; goto out_socket; } - err = setsockopt(umem->fd, SOL_XDP, XDP_UMEM_FILL_RING, - &umem->config.fill_size, - sizeof(umem->config.fill_size)); - if (err) { - err = -errno; - goto out_socket; - } - err = setsockopt(umem->fd, SOL_XDP, XDP_UMEM_COMPLETION_RING, - &umem->config.comp_size, - sizeof(umem->config.comp_size)); - if (err) { - err = -errno; - goto out_socket; - } - err = xsk_get_mmap_offsets(umem->fd, &off); - if (err) { - err = -errno; - goto out_socket; - } - - map = mmap(NULL, off.fr.desc + umem->config.fill_size * sizeof(__u64), - PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, umem->fd, - XDP_UMEM_PGOFF_FILL_RING); - if (map == MAP_FAILED) { - err = -errno; + err = xsk_create_umem_rings(umem, umem->fd, fill, comp); + if (err) goto out_socket; - } - - umem->fill = fill; - fill->mask = umem->config.fill_size - 1; - fill->size = umem->config.fill_size; - fill->producer = map + off.fr.producer; - fill->consumer = map + off.fr.consumer; - fill->flags = map + off.fr.flags; - fill->ring = map + off.fr.desc; - fill->cached_prod = *fill->producer; - /* cached_cons is "size" bigger than the real consumer pointer - * See xsk_prod_nb_free - */ - fill->cached_cons = *fill->consumer + umem->config.fill_size; - - map = mmap(NULL, off.cr.desc + umem->config.comp_size * sizeof(__u64), - PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, umem->fd, - XDP_UMEM_PGOFF_COMPLETION_RING); - if (map == MAP_FAILED) { - err = -errno; - goto out_mmap; - } - - umem->comp = comp; - comp->mask = umem->config.comp_size - 1; - comp->size = umem->config.comp_size; - comp->producer = map + off.cr.producer; - comp->consumer = map + off.cr.consumer; - comp->flags = map + off.cr.flags; - comp->ring = map + off.cr.desc; - comp->cached_prod = *comp->producer; - comp->cached_cons = *comp->consumer; + umem->fill_save = fill; + umem->comp_save = comp; *umem_ptr = umem; return 0; -out_mmap: - munmap(map, off.fr.desc + umem->config.fill_size * sizeof(__u64)); out_socket: close(umem->fd); out_umem_alloc: @@ -339,6 +353,7 @@ DEFAULT_VERSION(xsk_umem__create_v0_0_4, xsk_umem__create, LIBBPF_0.0.4) static int xsk_load_xdp_prog(struct xsk_socket *xsk) { static const int log_buf_size = 16 * 1024; + struct xsk_ctx *ctx = xsk->ctx; char log_buf[log_buf_size]; int err, prog_fd; @@ -366,7 +381,7 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) /* *(u32 *)(r10 - 4) = r2 */ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -4), /* r1 = xskmap[] */ - BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd), + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), /* r3 = XDP_PASS */ BPF_MOV64_IMM(BPF_REG_3, 2), /* call bpf_redirect_map */ @@ -378,7 +393,7 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) /* r2 += -4 */ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r1 = xskmap[] */ - BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd), + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), /* call bpf_map_lookup_elem */ BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), /* r1 = r0 */ @@ -390,7 +405,7 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) /* r2 = *(u32 *)(r10 - 4) */ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_10, -4), /* r1 = xskmap[] */ - BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd), + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), /* r3 = 0 */ BPF_MOV64_IMM(BPF_REG_3, 0), /* call bpf_redirect_map */ @@ -408,19 +423,21 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) return prog_fd; } - err = bpf_set_link_xdp_fd(xsk->ifindex, prog_fd, xsk->config.xdp_flags); + err = bpf_set_link_xdp_fd(xsk->ctx->ifindex, prog_fd, + xsk->config.xdp_flags); if (err) { close(prog_fd); return err; } - xsk->prog_fd = prog_fd; + ctx->prog_fd = prog_fd; return 0; } static int xsk_get_max_queues(struct xsk_socket *xsk) { struct ethtool_channels channels = { .cmd = ETHTOOL_GCHANNELS }; + struct xsk_ctx *ctx = xsk->ctx; struct ifreq ifr = {}; int fd, err, ret; @@ -429,7 +446,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) return -errno; ifr.ifr_data = (void *)&channels; - memcpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1); + memcpy(ifr.ifr_name, ctx->ifname, IFNAMSIZ - 1); ifr.ifr_name[IFNAMSIZ - 1] = '\0'; err = ioctl(fd, SIOCETHTOOL, &ifr); if (err && errno != EOPNOTSUPP) { @@ -457,6 +474,7 @@ out: static int xsk_create_bpf_maps(struct xsk_socket *xsk) { + struct xsk_ctx *ctx = xsk->ctx; int max_queues; int fd; @@ -469,15 +487,17 @@ static int xsk_create_bpf_maps(struct xsk_socket *xsk) if (fd < 0) return fd; - xsk->xsks_map_fd = fd; + ctx->xsks_map_fd = fd; return 0; } static void xsk_delete_bpf_maps(struct xsk_socket *xsk) { - bpf_map_delete_elem(xsk->xsks_map_fd, &xsk->queue_id); - close(xsk->xsks_map_fd); + struct xsk_ctx *ctx = xsk->ctx; + + bpf_map_delete_elem(ctx->xsks_map_fd, &ctx->queue_id); + close(ctx->xsks_map_fd); } static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) @@ -485,10 +505,11 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) __u32 i, *map_ids, num_maps, prog_len = sizeof(struct bpf_prog_info); __u32 map_len = sizeof(struct bpf_map_info); struct bpf_prog_info prog_info = {}; + struct xsk_ctx *ctx = xsk->ctx; struct bpf_map_info map_info; int fd, err; - err = bpf_obj_get_info_by_fd(xsk->prog_fd, &prog_info, &prog_len); + err = bpf_obj_get_info_by_fd(ctx->prog_fd, &prog_info, &prog_len); if (err) return err; @@ -502,11 +523,11 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) prog_info.nr_map_ids = num_maps; prog_info.map_ids = (__u64)(unsigned long)map_ids; - err = bpf_obj_get_info_by_fd(xsk->prog_fd, &prog_info, &prog_len); + err = bpf_obj_get_info_by_fd(ctx->prog_fd, &prog_info, &prog_len); if (err) goto out_map_ids; - xsk->xsks_map_fd = -1; + ctx->xsks_map_fd = -1; for (i = 0; i < prog_info.nr_map_ids; i++) { fd = bpf_map_get_fd_by_id(map_ids[i]); @@ -520,7 +541,7 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) } if (!strcmp(map_info.name, "xsks_map")) { - xsk->xsks_map_fd = fd; + ctx->xsks_map_fd = fd; continue; } @@ -528,7 +549,7 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) } err = 0; - if (xsk->xsks_map_fd == -1) + if (ctx->xsks_map_fd == -1) err = -ENOENT; out_map_ids: @@ -538,16 +559,19 @@ out_map_ids: static int xsk_set_bpf_maps(struct xsk_socket *xsk) { - return bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id, + struct xsk_ctx *ctx = xsk->ctx; + + return bpf_map_update_elem(ctx->xsks_map_fd, &ctx->queue_id, &xsk->fd, 0); } static int xsk_setup_xdp_prog(struct xsk_socket *xsk) { + struct xsk_ctx *ctx = xsk->ctx; __u32 prog_id = 0; int err; - err = bpf_get_link_xdp_id(xsk->ifindex, &prog_id, + err = bpf_get_link_xdp_id(ctx->ifindex, &prog_id, xsk->config.xdp_flags); if (err) return err; @@ -563,12 +587,12 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk) return err; } } else { - xsk->prog_fd = bpf_prog_get_fd_by_id(prog_id); - if (xsk->prog_fd < 0) + ctx->prog_fd = bpf_prog_get_fd_by_id(prog_id); + if (ctx->prog_fd < 0) return -errno; err = xsk_lookup_bpf_maps(xsk); if (err) { - close(xsk->prog_fd); + close(ctx->prog_fd); return err; } } @@ -577,25 +601,110 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk) err = xsk_set_bpf_maps(xsk); if (err) { xsk_delete_bpf_maps(xsk); - close(xsk->prog_fd); + close(ctx->prog_fd); return err; } return 0; } -int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, - __u32 queue_id, struct xsk_umem *umem, - struct xsk_ring_cons *rx, struct xsk_ring_prod *tx, - const struct xsk_socket_config *usr_config) +static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex, + __u32 queue_id) +{ + struct xsk_ctx *ctx; + + if (list_empty(&umem->ctx_list)) + return NULL; + + list_for_each_entry(ctx, &umem->ctx_list, list) { + if (ctx->ifindex == ifindex && ctx->queue_id == queue_id) { + ctx->refcount++; + return ctx; + } + } + + return NULL; +} + +static void xsk_put_ctx(struct xsk_ctx *ctx) +{ + struct xsk_umem *umem = ctx->umem; + struct xdp_mmap_offsets off; + int err; + + if (--ctx->refcount == 0) { + err = xsk_get_mmap_offsets(umem->fd, &off); + if (!err) { + munmap(ctx->fill->ring - off.fr.desc, + off.fr.desc + umem->config.fill_size * + sizeof(__u64)); + munmap(ctx->comp->ring - off.cr.desc, + off.cr.desc + umem->config.comp_size * + sizeof(__u64)); + } + + list_del(&ctx->list); + free(ctx); + } +} + +static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, + struct xsk_umem *umem, int ifindex, + const char *ifname, __u32 queue_id, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp) +{ + struct xsk_ctx *ctx; + int err; + + ctx = calloc(1, sizeof(*ctx)); + if (!ctx) + return NULL; + + if (!umem->fill_save) { + err = xsk_create_umem_rings(umem, xsk->fd, fill, comp); + if (err) { + free(ctx); + return NULL; + } + } else if (umem->fill_save != fill || umem->comp_save != comp) { + /* Copy over rings to new structs. */ + memcpy(fill, umem->fill_save, sizeof(*fill)); + memcpy(comp, umem->comp_save, sizeof(*comp)); + } + + ctx->ifindex = ifindex; + ctx->refcount = 1; + ctx->umem = umem; + ctx->queue_id = queue_id; + memcpy(ctx->ifname, ifname, IFNAMSIZ - 1); + ctx->ifname[IFNAMSIZ - 1] = '\0'; + + umem->fill_save = NULL; + umem->comp_save = NULL; + ctx->fill = fill; + ctx->comp = comp; + list_add(&ctx->list, &umem->ctx_list); + return ctx; +} + +int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, + const char *ifname, + __u32 queue_id, struct xsk_umem *umem, + struct xsk_ring_cons *rx, + struct xsk_ring_prod *tx, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_socket_config *usr_config) { void *rx_map = NULL, *tx_map = NULL; struct sockaddr_xdp sxdp = {}; struct xdp_mmap_offsets off; struct xsk_socket *xsk; - int err; + struct xsk_ctx *ctx; + int err, ifindex; - if (!umem || !xsk_ptr || !(rx || tx)) + if (!umem || !xsk_ptr || !(rx || tx) || !fill || !comp) return -EFAULT; xsk = calloc(1, sizeof(*xsk)); @@ -606,10 +715,10 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, if (err) goto out_xsk_alloc; - if (umem->refcount && - !(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) { - pr_warn("Error: shared umems not supported by libbpf supplied XDP program.\n"); - err = -EBUSY; + xsk->outstanding_tx = 0; + ifindex = if_nametoindex(ifname); + if (!ifindex) { + err = -errno; goto out_xsk_alloc; } @@ -623,16 +732,16 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, xsk->fd = umem->fd; } - xsk->outstanding_tx = 0; - xsk->queue_id = queue_id; - xsk->umem = umem; - xsk->ifindex = if_nametoindex(ifname); - if (!xsk->ifindex) { - err = -errno; - goto out_socket; + ctx = xsk_get_ctx(umem, ifindex, queue_id); + if (!ctx) { + ctx = xsk_create_ctx(xsk, umem, ifindex, ifname, queue_id, + fill, comp); + if (!ctx) { + err = -ENOMEM; + goto out_socket; + } } - memcpy(xsk->ifname, ifname, IFNAMSIZ - 1); - xsk->ifname[IFNAMSIZ - 1] = '\0'; + xsk->ctx = ctx; if (rx) { err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING, @@ -640,7 +749,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, sizeof(xsk->config.rx_size)); if (err) { err = -errno; - goto out_socket; + goto out_put_ctx; } } if (tx) { @@ -649,14 +758,14 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, sizeof(xsk->config.tx_size)); if (err) { err = -errno; - goto out_socket; + goto out_put_ctx; } } err = xsk_get_mmap_offsets(xsk->fd, &off); if (err) { err = -errno; - goto out_socket; + goto out_put_ctx; } if (rx) { @@ -666,7 +775,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, xsk->fd, XDP_PGOFF_RX_RING); if (rx_map == MAP_FAILED) { err = -errno; - goto out_socket; + goto out_put_ctx; } rx->mask = xsk->config.rx_size - 1; @@ -705,10 +814,10 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, xsk->tx = tx; sxdp.sxdp_family = PF_XDP; - sxdp.sxdp_ifindex = xsk->ifindex; - sxdp.sxdp_queue_id = xsk->queue_id; + sxdp.sxdp_ifindex = ctx->ifindex; + sxdp.sxdp_queue_id = ctx->queue_id; if (umem->refcount > 1) { - sxdp.sxdp_flags = XDP_SHARED_UMEM; + sxdp.sxdp_flags |= XDP_SHARED_UMEM; sxdp.sxdp_shared_umem_fd = umem->fd; } else { sxdp.sxdp_flags = xsk->config.bind_flags; @@ -720,7 +829,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, goto out_mmap_tx; } - xsk->prog_fd = -1; + ctx->prog_fd = -1; if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) { err = xsk_setup_xdp_prog(xsk); @@ -739,6 +848,8 @@ out_mmap_rx: if (rx) munmap(rx_map, off.rx.desc + xsk->config.rx_size * sizeof(struct xdp_desc)); +out_put_ctx: + xsk_put_ctx(ctx); out_socket: if (--umem->refcount) close(xsk->fd); @@ -747,25 +858,24 @@ out_xsk_alloc: return err; } -int xsk_umem__delete(struct xsk_umem *umem) +int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, + __u32 queue_id, struct xsk_umem *umem, + struct xsk_ring_cons *rx, struct xsk_ring_prod *tx, + const struct xsk_socket_config *usr_config) { - struct xdp_mmap_offsets off; - int err; + return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem, + rx, tx, umem->fill_save, + umem->comp_save, usr_config); +} +int xsk_umem__delete(struct xsk_umem *umem) +{ if (!umem) return 0; if (umem->refcount) return -EBUSY; - err = xsk_get_mmap_offsets(umem->fd, &off); - if (!err) { - munmap(umem->fill->ring - off.fr.desc, - off.fr.desc + umem->config.fill_size * sizeof(__u64)); - munmap(umem->comp->ring - off.cr.desc, - off.cr.desc + umem->config.comp_size * sizeof(__u64)); - } - close(umem->fd); free(umem); @@ -775,15 +885,16 @@ int xsk_umem__delete(struct xsk_umem *umem) void xsk_socket__delete(struct xsk_socket *xsk) { size_t desc_sz = sizeof(struct xdp_desc); + struct xsk_ctx *ctx = xsk->ctx; struct xdp_mmap_offsets off; int err; if (!xsk) return; - if (xsk->prog_fd != -1) { + if (ctx->prog_fd != -1) { xsk_delete_bpf_maps(xsk); - close(xsk->prog_fd); + close(ctx->prog_fd); } err = xsk_get_mmap_offsets(xsk->fd, &off); @@ -796,14 +907,15 @@ void xsk_socket__delete(struct xsk_socket *xsk) munmap(xsk->tx->ring - off.tx.desc, off.tx.desc + xsk->config.tx_size * desc_sz); } - } - xsk->umem->refcount--; + xsk_put_ctx(ctx); + + ctx->umem->refcount--; /* Do not close an fd that also has an associated umem connected * to it. */ - if (xsk->fd != xsk->umem->fd) + if (xsk->fd != ctx->umem->fd) close(xsk->fd); free(xsk); } diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h index 584f6820a639..1069c46364ff 100644 --- a/tools/lib/bpf/xsk.h +++ b/tools/lib/bpf/xsk.h @@ -234,6 +234,15 @@ LIBBPF_API int xsk_socket__create(struct xsk_socket **xsk, struct xsk_ring_cons *rx, struct xsk_ring_prod *tx, const struct xsk_socket_config *config); +LIBBPF_API int +xsk_socket__create_shared(struct xsk_socket **xsk_ptr, + const char *ifname, + __u32 queue_id, struct xsk_umem *umem, + struct xsk_ring_cons *rx, + struct xsk_ring_prod *tx, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_socket_config *config); /* Returns 0 for success and -EBUSY if the umem is still in use. */ LIBBPF_API int xsk_umem__delete(struct xsk_umem *umem); -- cgit v1.2.3 From 0201c575831171292489f14a8b6f79f98936b4d1 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:29 -0700 Subject: libbpf: Ensure ELF symbols table is found before further ELF processing libbpf ELF parsing logic might need symbols available before ELF parsing is completed, so we need to make sure that symbols table section is found in a separate pass before all the subsequent sections are processed. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200903203542.15944-2-andriin@fb.com --- tools/lib/bpf/libbpf.c | 40 +++++++++++++++++++++++++++++----------- 1 file changed, 29 insertions(+), 11 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b688aadf09c5..ac56d4db6d3e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2720,14 +2720,38 @@ static int bpf_object__elf_collect(struct bpf_object *obj) Elf *elf = obj->efile.elf; Elf_Data *btf_ext_data = NULL; Elf_Data *btf_data = NULL; - Elf_Scn *scn = NULL; int idx = 0, err = 0; + const char *name; + Elf_Data *data; + Elf_Scn *scn; + GElf_Shdr sh; + /* a bunch of ELF parsing functionality depends on processing symbols, + * so do the first pass and find the symbol table + */ + scn = NULL; while ((scn = elf_nextscn(elf, scn)) != NULL) { - const char *name; - GElf_Shdr sh; - Elf_Data *data; + if (elf_sec_hdr(obj, scn, &sh)) + return -LIBBPF_ERRNO__FORMAT; + + if (sh.sh_type == SHT_SYMTAB) { + if (obj->efile.symbols) { + pr_warn("elf: multiple symbol tables in %s\n", obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + data = elf_sec_data(obj, scn); + if (!data) + return -LIBBPF_ERRNO__FORMAT; + + obj->efile.symbols = data; + obj->efile.symbols_shndx = elf_ndxscn(scn); + obj->efile.strtabidx = sh.sh_link; + } + } + + scn = NULL; + while ((scn = elf_nextscn(elf, scn)) != NULL) { idx++; if (elf_sec_hdr(obj, scn, &sh)) @@ -2766,13 +2790,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) { btf_ext_data = data; } else if (sh.sh_type == SHT_SYMTAB) { - if (obj->efile.symbols) { - pr_warn("elf: multiple symbol tables in %s\n", obj->path); - return -LIBBPF_ERRNO__FORMAT; - } - obj->efile.symbols = data; - obj->efile.symbols_shndx = idx; - obj->efile.strtabidx = sh.sh_link; + /* already processed during the first pass above */ } else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) { if (sh.sh_flags & SHF_EXECINSTR) { if (strcmp(name, ".text") == 0) -- cgit v1.2.3 From c112239272c6bacf7fcd0a0dc71999ad8eb1c55c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:30 -0700 Subject: libbpf: Parse multi-function sections into multiple BPF programs Teach libbpf how to parse code sections into potentially multiple bpf_program instances, based on ELF FUNC symbols. Each BPF program will keep track of its position within containing ELF section for translating section instruction offsets into program instruction offsets: regardless of BPF program's location in ELF section, it's first instruction is always at local instruction offset 0, so when libbpf is working with relocations (which use section-based instruction offsets) this is critical to make proper translations. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200903203542.15944-3-andriin@fb.com --- tools/lib/bpf/libbpf.c | 249 ++++++++++++++++++++++++++++--------------------- 1 file changed, 142 insertions(+), 107 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ac56d4db6d3e..57f87eee5be5 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -217,20 +217,45 @@ struct bpf_sec_def { * linux/filter.h. */ struct bpf_program { - /* Index in elf obj file, for relocation use. */ - int idx; - char *name; - int prog_ifindex; - char *section_name; const struct bpf_sec_def *sec_def; + char *section_name; + size_t sec_idx; + /* this program's instruction offset (in number of instructions) + * within its containing ELF section + */ + size_t sec_insn_off; + /* number of original instructions in ELF section belonging to this + * program, not taking into account subprogram instructions possible + * appended later during relocation + */ + size_t sec_insn_cnt; + /* Offset (in number of instructions) of the start of instruction + * belonging to this BPF program within its containing main BPF + * program. For the entry-point (main) BPF program, this is always + * zero. For a sub-program, this gets reset before each of main BPF + * programs are processed and relocated and is used to determined + * whether sub-program was already appended to the main program, and + * if yes, at which instruction offset. + */ + size_t sub_insn_off; + + char *name; /* section_name with / replaced by _; makes recursive pinning * in bpf_object__pin_programs easier */ char *pin_name; + + /* instructions that belong to BPF program; insns[0] is located at + * sec_insn_off instruction within its ELF section in ELF file, so + * when mapping ELF file instruction index to the local instruction, + * one needs to subtract sec_insn_off; and vice versa. + */ struct bpf_insn *insns; + /* actual number of instruction in this BPF program's image; for + * entry-point BPF programs this includes the size of main program + * itself plus all the used sub-programs, appended at the end + */ size_t insns_cnt, main_prog_cnt; - enum bpf_prog_type type; - bool load; struct reloc_desc *reloc_desc; int nr_reloc; @@ -246,7 +271,10 @@ struct bpf_program { void *priv; bpf_program_clear_priv_t clear_priv; + bool load; + enum bpf_prog_type type; enum bpf_attach_type expected_attach_type; + int prog_ifindex; __u32 attach_btf_id; __u32 attach_prog_fd; void *func_info; @@ -446,6 +474,8 @@ static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name); static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr); static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn); static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn); +static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, + size_t off, __u32 sym_type, GElf_Sym *sym); void bpf_program__unload(struct bpf_program *prog) { @@ -493,7 +523,7 @@ static void bpf_program__exit(struct bpf_program *prog) prog->nr_reloc = 0; prog->insns_cnt = 0; - prog->idx = -1; + prog->sec_idx = -1; } static char *__bpf_program__pin_name(struct bpf_program *prog) @@ -508,130 +538,118 @@ static char *__bpf_program__pin_name(struct bpf_program *prog) } static int -bpf_program__init(void *data, size_t size, const char *section_name, int idx, - struct bpf_program *prog) +bpf_program__init(struct bpf_program *prog, const char *name, + size_t sec_idx, const char *sec_name, size_t sec_off, + void *insn_data, size_t insn_data_sz) { - const size_t bpf_insn_sz = sizeof(struct bpf_insn); - - if (size == 0 || size % bpf_insn_sz) { - pr_warn("corrupted section '%s', size: %zu\n", - section_name, size); + if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) { + pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n", + sec_name, name, sec_off, insn_data_sz); return -EINVAL; } - memset(prog, 0, sizeof(*prog)); + prog->sec_idx = sec_idx; + prog->sec_insn_off = sec_off / BPF_INSN_SZ; + prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ; + /* insns_cnt can later be increased by appending used subprograms */ + prog->insns_cnt = prog->sec_insn_cnt; - prog->section_name = strdup(section_name); - if (!prog->section_name) { - pr_warn("failed to alloc name for prog under section(%d) %s\n", - idx, section_name); + prog->type = BPF_PROG_TYPE_UNSPEC; + prog->load = true; + + prog->instances.fds = NULL; + prog->instances.nr = -1; + + prog->section_name = strdup(sec_name); + if (!prog->section_name) + goto errout; + + prog->name = strdup(name); + if (!prog->name) goto errout; - } prog->pin_name = __bpf_program__pin_name(prog); - if (!prog->pin_name) { - pr_warn("failed to alloc pin name for prog under section(%d) %s\n", - idx, section_name); + if (!prog->pin_name) goto errout; - } - prog->insns = malloc(size); - if (!prog->insns) { - pr_warn("failed to alloc insns for prog under section %s\n", - section_name); + prog->insns = malloc(insn_data_sz); + if (!prog->insns) goto errout; - } - prog->insns_cnt = size / bpf_insn_sz; - memcpy(prog->insns, data, size); - prog->idx = idx; - prog->instances.fds = NULL; - prog->instances.nr = -1; - prog->type = BPF_PROG_TYPE_UNSPEC; - prog->load = true; + memcpy(prog->insns, insn_data, insn_data_sz); return 0; errout: + pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name); bpf_program__exit(prog); return -ENOMEM; } static int -bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, - const char *section_name, int idx) +bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, + const char *sec_name, int sec_idx) { - struct bpf_program prog, *progs; + struct bpf_program *prog, *progs; + void *data = sec_data->d_buf; + size_t sec_sz = sec_data->d_size, sec_off, prog_sz; int nr_progs, err; - - err = bpf_program__init(data, size, section_name, idx, &prog); - if (err) - return err; + const char *name; + GElf_Sym sym; progs = obj->programs; nr_progs = obj->nr_programs; + sec_off = 0; - progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(progs[0])); - if (!progs) { - /* - * In this case the original obj->programs - * is still valid, so don't need special treat for - * bpf_close_object(). - */ - pr_warn("failed to alloc a new program under section '%s'\n", - section_name); - bpf_program__exit(&prog); - return -ENOMEM; - } - - pr_debug("elf: found program '%s'\n", prog.section_name); - obj->programs = progs; - obj->nr_programs = nr_progs + 1; - prog.obj = obj; - progs[nr_progs] = prog; - return 0; -} - -static int -bpf_object__init_prog_names(struct bpf_object *obj) -{ - Elf_Data *symbols = obj->efile.symbols; - struct bpf_program *prog; - size_t pi, si; + while (sec_off < sec_sz) { + if (elf_sym_by_sec_off(obj, sec_idx, sec_off, STT_FUNC, &sym)) { + pr_warn("sec '%s': failed to find program symbol at offset %zu\n", + sec_name, sec_off); + return -LIBBPF_ERRNO__FORMAT; + } - for (pi = 0; pi < obj->nr_programs; pi++) { - const char *name = NULL; + prog_sz = sym.st_size; - prog = &obj->programs[pi]; + name = elf_sym_str(obj, sym.st_name); + if (!name) { + pr_warn("sec '%s': failed to get symbol name for offset %zu\n", + sec_name, sec_off); + return -LIBBPF_ERRNO__FORMAT; + } - for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name; si++) { - GElf_Sym sym; + if (sec_off + prog_sz > sec_sz) { + pr_warn("sec '%s': program at offset %zu crosses section boundary\n", + sec_name, sec_off); + return -LIBBPF_ERRNO__FORMAT; + } - if (!gelf_getsym(symbols, si, &sym)) - continue; - if (sym.st_shndx != prog->idx) - continue; - if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL) - continue; + pr_debug("sec '%s': found program '%s' at offset %zu, code size %zu bytes\n", + sec_name, name, sec_off, prog_sz); - name = elf_sym_str(obj, sym.st_name); - if (!name) { - pr_warn("prog '%s': failed to get symbol name\n", - prog->section_name); - return -LIBBPF_ERRNO__LIBELF; - } + progs = reallocarray(progs, nr_progs + 1, sizeof(*progs)); + if (!progs) { + /* + * In this case the original obj->programs + * is still valid, so don't need special treat for + * bpf_close_object(). + */ + pr_warn("sec '%s': failed to alloc memory for new program '%s'\n", + sec_name, name); + return -ENOMEM; } + obj->programs = progs; - if (!name && prog->idx == obj->efile.text_shndx) - name = ".text"; + prog = &progs[nr_progs]; + memset(prog, 0, sizeof(*prog)); + prog->obj = obj; - if (!name) { - pr_warn("prog '%s': failed to find program symbol\n", - prog->section_name); - return -EINVAL; - } + err = bpf_program__init(prog, name, sec_idx, sec_name, sec_off, + data + sec_off, prog_sz); + if (err) + return err; - prog->name = strdup(name); - if (!prog->name) - return -ENOMEM; + nr_progs++; + obj->nr_programs = nr_progs; + + sec_off += prog_sz; } return 0; @@ -2675,6 +2693,26 @@ static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) return data; } +static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, + size_t off, __u32 sym_type, GElf_Sym *sym) +{ + Elf_Data *symbols = obj->efile.symbols; + size_t n = symbols->d_size / sizeof(GElf_Sym); + int i; + + for (i = 0; i < n; i++) { + if (!gelf_getsym(symbols, i, sym)) + continue; + if (sym->st_shndx != sec_idx || sym->st_value != off) + continue; + if (GELF_ST_TYPE(sym->st_info) != sym_type) + continue; + return 0; + } + + return -ENOENT; +} + static bool is_sec_name_dwarf(const char *name) { /* approximation, but the actual list is too long */ @@ -2795,9 +2833,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (sh.sh_flags & SHF_EXECINSTR) { if (strcmp(name, ".text") == 0) obj->efile.text_shndx = idx; - err = bpf_object__add_program(obj, data->d_buf, - data->d_size, - name, idx); + err = bpf_object__add_programs(obj, data, name, idx); if (err) return err; } else if (strcmp(name, DATA_SEC) == 0) { @@ -3183,7 +3219,7 @@ bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx) for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (prog->idx == idx) + if (prog->sec_idx == idx) return prog; } return NULL; @@ -5660,7 +5696,7 @@ bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj, size_t new_cnt; int err; - if (prog->idx != obj->efile.text_shndx && prog->main_prog_cnt == 0) { + if (prog->sec_idx != obj->efile.text_shndx && prog->main_prog_cnt == 0) { text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx); if (!text) { pr_warn("no .text section found yet relo into text exist\n"); @@ -5783,7 +5819,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (prog->idx != obj->efile.text_shndx) + if (prog->sec_idx != obj->efile.text_shndx) continue; err = bpf_program__relocate(prog, obj); @@ -5799,7 +5835,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (prog->idx == obj->efile.text_shndx) + if (prog->sec_idx == obj->efile.text_shndx) continue; err = bpf_program__relocate(prog, obj); @@ -6215,7 +6251,7 @@ out: static bool bpf_program__is_function_storage(const struct bpf_program *prog, const struct bpf_object *obj) { - return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls; + return prog->sec_idx == obj->efile.text_shndx && obj->has_pseudo_calls; } static int @@ -6298,7 +6334,6 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, err = err ? : bpf_object__collect_externs(obj); err = err ? : bpf_object__finalize_btf(obj); err = err ? : bpf_object__init_maps(obj, opts); - err = err ? : bpf_object__init_prog_names(obj); err = err ? : bpf_object__collect_reloc(obj); if (err) goto out; -- cgit v1.2.3 From db2b8b06423c7eb4abcb4310b7234f00b30d7730 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:31 -0700 Subject: libbpf: Support CO-RE relocations for multi-prog sections Fix up CO-RE relocation code to handle relocations against ELF sections containing multiple BPF programs. This requires lookup of a BPF program by its section name and instruction index it contains. While it could have been done as a simple loop, it could run into performance issues pretty quickly, as number of CO-RE relocations can be quite large in real-world applications, and each CO-RE relocation incurs BPF program look up now. So instead of simple loop, implement a binary search by section name + insn offset. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200903203542.15944-4-andriin@fb.com --- tools/lib/bpf/libbpf.c | 82 +++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 74 insertions(+), 8 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 57f87eee5be5..11ad230ec20c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2753,6 +2753,18 @@ static bool ignore_elf_section(GElf_Shdr *hdr, const char *name) return false; } +static int cmp_progs(const void *_a, const void *_b) +{ + const struct bpf_program *a = _a; + const struct bpf_program *b = _b; + + if (a->sec_idx != b->sec_idx) + return a->sec_idx < b->sec_idx ? -1 : 1; + + /* sec_insn_off can't be the same within the section */ + return a->sec_insn_off < b->sec_insn_off ? -1 : 1; +} + static int bpf_object__elf_collect(struct bpf_object *obj) { Elf *elf = obj->efile.elf; @@ -2887,6 +2899,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj) pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } + + /* sort BPF programs by section name and in-section instruction offset + * for faster search */ + qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs); + return bpf_object__init_btf(obj, btf_data, btf_ext_data); } @@ -3415,6 +3432,37 @@ static int bpf_program__record_reloc(struct bpf_program *prog, return 0; } +static bool prog_contains_insn(const struct bpf_program *prog, size_t insn_idx) +{ + return insn_idx >= prog->sec_insn_off && + insn_idx < prog->sec_insn_off + prog->sec_insn_cnt; +} + +static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, + size_t sec_idx, size_t insn_idx) +{ + int l = 0, r = obj->nr_programs - 1, m; + struct bpf_program *prog; + + while (l < r) { + m = l + (r - l + 1) / 2; + prog = &obj->programs[m]; + + if (prog->sec_idx < sec_idx || + (prog->sec_idx == sec_idx && prog->sec_insn_off <= insn_idx)) + l = m; + else + r = m - 1; + } + /* matching program could be at index l, but it still might be the + * wrong one, so we need to double check conditions for the last time + */ + prog = &obj->programs[l]; + if (prog->sec_idx == sec_idx && prog_contains_insn(prog, insn_idx)) + return prog; + return NULL; +} + static int bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, Elf_Data *data, struct bpf_object *obj) @@ -5229,6 +5277,11 @@ static int bpf_core_patch_insn(struct bpf_program *prog, if (relo->insn_off % BPF_INSN_SZ) return -EINVAL; insn_idx = relo->insn_off / BPF_INSN_SZ; + /* adjust insn_idx from section frame of reference to the local + * program's frame of reference; (sub-)program code is not yet + * relocated, so it's enough to just subtract in-section offset + */ + insn_idx = insn_idx - prog->sec_insn_off; insn = &prog->insns[insn_idx]; class = BPF_CLASS(insn->code); @@ -5619,7 +5672,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) struct bpf_program *prog; struct btf *targ_btf; const char *sec_name; - int i, err = 0; + int i, err = 0, insn_idx, sec_idx; if (obj->btf_ext->core_relo_info.len == 0) return 0; @@ -5646,24 +5699,37 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) err = -EINVAL; goto out; } + /* bpf_object's ELF is gone by now so it's not easy to find + * section index by section name, but we can find *any* + * bpf_program within desired section name and use it's + * prog->sec_idx to do a proper search by section index and + * instruction offset + */ prog = NULL; for (i = 0; i < obj->nr_programs; i++) { - if (!strcmp(obj->programs[i].section_name, sec_name)) { - prog = &obj->programs[i]; + prog = &obj->programs[i]; + if (strcmp(prog->section_name, sec_name) == 0) break; - } } if (!prog) { - pr_warn("failed to find program '%s' for CO-RE offset relocation\n", - sec_name); - err = -EINVAL; - goto out; + pr_warn("sec '%s': failed to find a BPF program\n", sec_name); + return -ENOENT; } + sec_idx = prog->sec_idx; pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info); for_each_btf_ext_rec(seg, sec, i, rec) { + insn_idx = rec->insn_off / BPF_INSN_SZ; + prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); + if (!prog) { + pr_warn("sec '%s': failed to find program at insn #%d for CO-RE offset relocation #%d\n", + sec_name, insn_idx, i); + err = -EINVAL; + goto out; + } + err = bpf_core_apply_relo(prog, rec, i, obj->btf, targ_btf, cand_cache); if (err) { -- cgit v1.2.3 From c3c556966de7a0d5f8c908f407c673070fcdbf2b Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:32 -0700 Subject: libbpf: Make RELO_CALL work for multi-prog sections and sub-program calls This patch implements general and correct logic for bpf-to-bpf sub-program calls. Only sub-programs used (called into) from entry-point (main) BPF program are going to be appended at the end of main BPF program. This ensures that BPF verifier won't encounter any dead code due to copying unreferenced sub-program. This change means that each entry-point (main) BPF program might have a different set of sub-programs appended to it and potentially in different order. This has implications on how sub-program call relocations need to be handled, described below. All relocations are now split into two categores: data references (maps and global variables) and code references (sub-program calls). This distinction is important because data references need to be relocated just once per each BPF program and sub-program. These relocation are agnostic to instruction locations, because they are not code-relative and they are relocating against static targets (maps, variables with fixes offsets, etc). Sub-program RELO_CALL relocations, on the other hand, are highly-dependent on code position, because they are recorded as instruction-relative offset. So BPF sub-programs (those that do calls into other sub-programs) can't be relocated once, they need to be relocated each time such a sub-program is appended at the end of the main entry-point BPF program. As mentioned above, each main BPF program might have different subset and differen order of sub-programs, so call relocations can't be done just once. Splitting data reference and calls relocations as described above allows to do this efficiently and cleanly. bpf_object__find_program_by_name() will now ignore non-entry BPF programs. Previously one could have looked up '.text' fake BPF program, but the existence of such BPF program was always an implementation detail and you can't do much useful with it. Now, though, all non-entry sub-programs get their own BPF program with name corresponding to a function name, so there is no more '.text' name for BPF program. This means there is no regression, effectively, w.r.t. API behavior. But this is important aspect to highlight, because it's going to be critical once libbpf implements static linking of BPF programs. Non-entry static BPF programs will be allowed to have conflicting names, but global and main-entry BPF program names should be unique. Just like with normal user-space linking process. So it's important to restrict this aspect right now, keep static and non-entry functions as internal implementation details, and not have to deal with regressions in behavior later. This patch leaves .BTF.ext adjustment as is until next patch. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200903203542.15944-5-andriin@fb.com --- tools/lib/bpf/libbpf.c | 518 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 380 insertions(+), 138 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 11ad230ec20c..4e32a1028379 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -193,6 +193,7 @@ struct reloc_desc { int insn_idx; int map_idx; int sym_off; + bool processed; }; struct bpf_sec_def; @@ -255,7 +256,7 @@ struct bpf_program { * entry-point BPF programs this includes the size of main program * itself plus all the used sub-programs, appended at the end */ - size_t insns_cnt, main_prog_cnt; + size_t insns_cnt; struct reloc_desc *reloc_desc; int nr_reloc; @@ -412,7 +413,7 @@ struct bpf_object { int kconfig_map_idx; bool loaded; - bool has_pseudo_calls; + bool has_subcalls; /* * Information when doing elf related work. Only valid if fd @@ -537,17 +538,32 @@ static char *__bpf_program__pin_name(struct bpf_program *prog) return name; } +static bool insn_is_subprog_call(const struct bpf_insn *insn) +{ + return BPF_CLASS(insn->code) == BPF_JMP && + BPF_OP(insn->code) == BPF_CALL && + BPF_SRC(insn->code) == BPF_K && + insn->src_reg == BPF_PSEUDO_CALL && + insn->dst_reg == 0 && + insn->off == 0; +} + static int -bpf_program__init(struct bpf_program *prog, const char *name, - size_t sec_idx, const char *sec_name, size_t sec_off, - void *insn_data, size_t insn_data_sz) +bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, + const char *name, size_t sec_idx, const char *sec_name, + size_t sec_off, void *insn_data, size_t insn_data_sz) { + int i; + if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) { pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n", sec_name, name, sec_off, insn_data_sz); return -EINVAL; } + memset(prog, 0, sizeof(*prog)); + prog->obj = obj; + prog->sec_idx = sec_idx; prog->sec_insn_off = sec_off / BPF_INSN_SZ; prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ; @@ -577,6 +593,13 @@ bpf_program__init(struct bpf_program *prog, const char *name, goto errout; memcpy(prog->insns, insn_data, insn_data_sz); + for (i = 0; i < prog->insns_cnt; i++) { + if (insn_is_subprog_call(&prog->insns[i])) { + obj->has_subcalls = true; + break; + } + } + return 0; errout: pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name); @@ -621,10 +644,10 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, return -LIBBPF_ERRNO__FORMAT; } - pr_debug("sec '%s': found program '%s' at offset %zu, code size %zu bytes\n", - sec_name, name, sec_off, prog_sz); + pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n", + sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz); - progs = reallocarray(progs, nr_progs + 1, sizeof(*progs)); + progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(*progs)); if (!progs) { /* * In this case the original obj->programs @@ -638,11 +661,9 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, obj->programs = progs; prog = &progs[nr_progs]; - memset(prog, 0, sizeof(*prog)); - prog->obj = obj; - err = bpf_program__init(prog, name, sec_idx, sec_name, sec_off, - data + sec_off, prog_sz); + err = bpf_object__init_prog(obj, prog, name, sec_idx, sec_name, + sec_off, data + sec_off, prog_sz); if (err) return err; @@ -3255,6 +3276,12 @@ bpf_object__find_program_by_title(const struct bpf_object *obj, return NULL; } +static bool prog_is_subprog(const struct bpf_object *obj, + const struct bpf_program *prog) +{ + return prog->sec_idx == obj->efile.text_shndx && obj->has_subcalls; +} + struct bpf_program * bpf_object__find_program_by_name(const struct bpf_object *obj, const char *name) @@ -3262,6 +3289,8 @@ bpf_object__find_program_by_name(const struct bpf_object *obj, struct bpf_program *prog; bpf_object__for_each_program(prog, obj) { + if (prog_is_subprog(obj, prog)) + continue; if (!strcmp(prog->name, name)) return prog; } @@ -3311,6 +3340,8 @@ static int bpf_program__record_reloc(struct bpf_program *prog, const char *sym_sec_name; struct bpf_map *map; + reloc_desc->processed = false; + /* sub-program call relocation */ if (insn->code == (BPF_JMP | BPF_CALL)) { if (insn->src_reg != BPF_PSEUDO_CALL) { @@ -3332,7 +3363,6 @@ static int bpf_program__record_reloc(struct bpf_program *prog, reloc_desc->type = RELO_CALL; reloc_desc->insn_idx = insn_idx; reloc_desc->sym_off = sym->st_value; - obj->has_pseudo_calls = true; return 0; } @@ -3464,13 +3494,18 @@ static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, } static int -bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, - Elf_Data *data, struct bpf_object *obj) +bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data *data) { Elf_Data *symbols = obj->efile.symbols; const char *relo_sec_name, *sec_name; size_t sec_idx = shdr->sh_info; + struct bpf_program *prog; + struct reloc_desc *relos; int err, i, nrels; + const char *sym_name; + __u32 insn_idx; + GElf_Sym sym; + GElf_Rel rel; relo_sec_name = elf_sec_str(obj, shdr->sh_name); sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); @@ -3481,19 +3516,7 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, relo_sec_name, sec_idx, sec_name); nrels = shdr->sh_size / shdr->sh_entsize; - prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels); - if (!prog->reloc_desc) { - pr_warn("failed to alloc memory in relocation\n"); - return -ENOMEM; - } - prog->nr_reloc = nrels; - for (i = 0; i < nrels; i++) { - const char *sym_name; - __u32 insn_idx; - GElf_Sym sym; - GElf_Rel rel; - if (!gelf_getrel(data, i, &rel)) { pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i); return -LIBBPF_ERRNO__FORMAT; @@ -3510,15 +3533,42 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, } insn_idx = rel.r_offset / BPF_INSN_SZ; - sym_name = elf_sym_str(obj, sym.st_name) ?: ""; + /* relocations against static functions are recorded as + * relocations against the section that contains a function; + * in such case, symbol will be STT_SECTION and sym.st_name + * will point to empty string (0), so fetch section name + * instead + */ + if (GELF_ST_TYPE(sym.st_info) == STT_SECTION && sym.st_name == 0) + sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym.st_shndx)); + else + sym_name = elf_sym_str(obj, sym.st_name); + sym_name = sym_name ?: "reloc_desc[i], + prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); + if (!prog) { + pr_warn("sec '%s': relo #%d: program not found in section '%s' for insn #%u\n", + relo_sec_name, i, sec_name, insn_idx); + return -LIBBPF_ERRNO__RELOC; + } + + relos = libbpf_reallocarray(prog->reloc_desc, + prog->nr_reloc + 1, sizeof(*relos)); + if (!relos) + return -ENOMEM; + prog->reloc_desc = relos; + + /* adjust insn_idx to local BPF program frame of reference */ + insn_idx -= prog->sec_insn_off; + err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc], insn_idx, sym_name, &sym, &rel); if (err) return err; + + prog->nr_reloc++; } return 0; } @@ -5753,89 +5803,32 @@ out: return err; } +/* Relocate data references within program code: + * - map references; + * - global variable references; + * - extern references. + */ static int -bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj, - struct reloc_desc *relo) -{ - struct bpf_insn *insn, *new_insn; - struct bpf_program *text; - size_t new_cnt; - int err; - - if (prog->sec_idx != obj->efile.text_shndx && prog->main_prog_cnt == 0) { - text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx); - if (!text) { - pr_warn("no .text section found yet relo into text exist\n"); - return -LIBBPF_ERRNO__RELOC; - } - new_cnt = prog->insns_cnt + text->insns_cnt; - new_insn = libbpf_reallocarray(prog->insns, new_cnt, sizeof(*insn)); - if (!new_insn) { - pr_warn("oom in prog realloc\n"); - return -ENOMEM; - } - prog->insns = new_insn; - - if (obj->btf_ext) { - err = bpf_program_reloc_btf_ext(prog, obj, - text->section_name, - prog->insns_cnt); - if (err) - return err; - } - - memcpy(new_insn + prog->insns_cnt, text->insns, - text->insns_cnt * sizeof(*insn)); - prog->main_prog_cnt = prog->insns_cnt; - prog->insns_cnt = new_cnt; - pr_debug("added %zd insn from %s to prog %s\n", - text->insns_cnt, text->section_name, - prog->section_name); - } - - insn = &prog->insns[relo->insn_idx]; - insn->imm += relo->sym_off / 8 + prog->main_prog_cnt - relo->insn_idx; - return 0; -} - -static int -bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) +bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) { - int i, err; - - if (!prog) - return 0; - - if (obj->btf_ext) { - err = bpf_program_reloc_btf_ext(prog, obj, - prog->section_name, 0); - if (err) - return err; - } - - if (!prog->reloc_desc) - return 0; + int i; for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; struct bpf_insn *insn = &prog->insns[relo->insn_idx]; struct extern_desc *ext; - if (relo->insn_idx + 1 >= (int)prog->insns_cnt) { - pr_warn("relocation out of range: '%s'\n", - prog->section_name); - return -LIBBPF_ERRNO__RELOC; - } - switch (relo->type) { case RELO_LD64: insn[0].src_reg = BPF_PSEUDO_MAP_FD; insn[0].imm = obj->maps[relo->map_idx].fd; + relo->processed = true; break; case RELO_DATA: insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; insn[1].imm = insn[0].imm + relo->sym_off; insn[0].imm = obj->maps[relo->map_idx].fd; + relo->processed = true; break; case RELO_EXTERN: ext = &obj->externs[relo->sym_off]; @@ -5847,11 +5840,10 @@ bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) insn[0].imm = (__u32)ext->ksym.addr; insn[1].imm = ext->ksym.addr >> 32; } + relo->processed = true; break; case RELO_CALL: - err = bpf_program__reloc_text(prog, obj, relo); - if (err) - return err; + /* will be handled as a follow up pass */ break; default: pr_warn("prog '%s': relo #%d: bad relo type %d\n", @@ -5860,8 +5852,244 @@ bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) } } - zfree(&prog->reloc_desc); - prog->nr_reloc = 0; + return 0; +} + +static int cmp_relo_by_insn_idx(const void *key, const void *elem) +{ + size_t insn_idx = *(const size_t *)key; + const struct reloc_desc *relo = elem; + + if (insn_idx == relo->insn_idx) + return 0; + return insn_idx < relo->insn_idx ? -1 : 1; +} + +static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx) +{ + return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc, + sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx); +} + +static int +bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, + struct bpf_program *prog) +{ + size_t sub_insn_idx, insn_idx, new_cnt; + struct bpf_program *subprog; + struct bpf_insn *insns, *insn; + struct reloc_desc *relo; + int err; + + err = reloc_prog_func_and_line_info(obj, main_prog, prog); + if (err) + return err; + + for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) { + insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; + if (!insn_is_subprog_call(insn)) + continue; + + relo = find_prog_insn_relo(prog, insn_idx); + if (relo && relo->type != RELO_CALL) { + pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n", + prog->name, insn_idx, relo->type); + return -LIBBPF_ERRNO__RELOC; + } + if (relo) { + /* sub-program instruction index is a combination of + * an offset of a symbol pointed to by relocation and + * call instruction's imm field; for global functions, + * call always has imm = -1, but for static functions + * relocation is against STT_SECTION and insn->imm + * points to a start of a static function + */ + sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + } else { + /* if subprogram call is to a static function within + * the same ELF section, there won't be any relocation + * emitted, but it also means there is no additional + * offset necessary, insns->imm is relative to + * instruction's original position within the section + */ + sub_insn_idx = prog->sec_insn_off + insn_idx + insn->imm + 1; + } + + /* we enforce that sub-programs should be in .text section */ + subprog = find_prog_by_sec_insn(obj, obj->efile.text_shndx, sub_insn_idx); + if (!subprog) { + pr_warn("prog '%s': no .text section found yet sub-program call exists\n", + prog->name); + return -LIBBPF_ERRNO__RELOC; + } + + /* if it's the first call instruction calling into this + * subprogram (meaning this subprog hasn't been processed + * yet) within the context of current main program: + * - append it at the end of main program's instructions blog; + * - process is recursively, while current program is put on hold; + * - if that subprogram calls some other not yet processes + * subprogram, same thing will happen recursively until + * there are no more unprocesses subprograms left to append + * and relocate. + */ + if (subprog->sub_insn_off == 0) { + subprog->sub_insn_off = main_prog->insns_cnt; + + new_cnt = main_prog->insns_cnt + subprog->insns_cnt; + insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns)); + if (!insns) { + pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name); + return -ENOMEM; + } + main_prog->insns = insns; + main_prog->insns_cnt = new_cnt; + + memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns, + subprog->insns_cnt * sizeof(*insns)); + + pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n", + main_prog->name, subprog->insns_cnt, subprog->name); + + err = bpf_object__reloc_code(obj, main_prog, subprog); + if (err) + return err; + } + + /* main_prog->insns memory could have been re-allocated, so + * calculate pointer again + */ + insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; + /* calculate correct instruction position within current main + * prog; each main prog can have a different set of + * subprograms appended (potentially in different order as + * well), so position of any subprog can be different for + * different main programs */ + insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1; + + if (relo) + relo->processed = true; + + pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n", + prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off); + } + + return 0; +} + +/* + * Relocate sub-program calls. + * + * Algorithm operates as follows. Each entry-point BPF program (referred to as + * main prog) is processed separately. For each subprog (non-entry functions, + * that can be called from either entry progs or other subprogs) gets their + * sub_insn_off reset to zero. This serves as indicator that this subprogram + * hasn't been yet appended and relocated within current main prog. Once its + * relocated, sub_insn_off will point at the position within current main prog + * where given subprog was appended. This will further be used to relocate all + * the call instructions jumping into this subprog. + * + * We start with main program and process all call instructions. If the call + * is into a subprog that hasn't been processed (i.e., subprog->sub_insn_off + * is zero), subprog instructions are appended at the end of main program's + * instruction array. Then main program is "put on hold" while we recursively + * process newly appended subprogram. If that subprogram calls into another + * subprogram that hasn't been appended, new subprogram is appended again to + * the *main* prog's instructions (subprog's instructions are always left + * untouched, as they need to be in unmodified state for subsequent main progs + * and subprog instructions are always sent only as part of a main prog) and + * the process continues recursively. Once all the subprogs called from a main + * prog or any of its subprogs are appended (and relocated), all their + * positions within finalized instructions array are known, so it's easy to + * rewrite call instructions with correct relative offsets, corresponding to + * desired target subprog. + * + * Its important to realize that some subprogs might not be called from some + * main prog and any of its called/used subprogs. Those will keep their + * subprog->sub_insn_off as zero at all times and won't be appended to current + * main prog and won't be relocated within the context of current main prog. + * They might still be used from other main progs later. + * + * Visually this process can be shown as below. Suppose we have two main + * programs mainA and mainB and BPF object contains three subprogs: subA, + * subB, and subC. mainA calls only subA, mainB calls only subC, but subA and + * subC both call subB: + * + * +--------+ +-------+ + * | v v | + * +--+---+ +--+-+-+ +---+--+ + * | subA | | subB | | subC | + * +--+---+ +------+ +---+--+ + * ^ ^ + * | | + * +---+-------+ +------+----+ + * | mainA | | mainB | + * +-----------+ +-----------+ + * + * We'll start relocating mainA, will find subA, append it and start + * processing sub A recursively: + * + * +-----------+------+ + * | mainA | subA | + * +-----------+------+ + * + * At this point we notice that subB is used from subA, so we append it and + * relocate (there are no further subcalls from subB): + * + * +-----------+------+------+ + * | mainA | subA | subB | + * +-----------+------+------+ + * + * At this point, we relocate subA calls, then go one level up and finish with + * relocatin mainA calls. mainA is done. + * + * For mainB process is similar but results in different order. We start with + * mainB and skip subA and subB, as mainB never calls them (at least + * directly), but we see subC is needed, so we append and start processing it: + * + * +-----------+------+ + * | mainB | subC | + * +-----------+------+ + * Now we see subC needs subB, so we go back to it, append and relocate it: + * + * +-----------+------+------+ + * | mainB | subC | subB | + * +-----------+------+------+ + * + * At this point we unwind recursion, relocate calls in subC, then in mainB. + */ +static int +bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) +{ + struct bpf_program *subprog; + int i, j, err; + + if (obj->btf_ext) { + err = bpf_program_reloc_btf_ext(prog, obj, + prog->section_name, 0); + if (err) + return err; + } + + /* mark all subprogs as not relocated (yet) within the context of + * current main program + */ + for (i = 0; i < obj->nr_programs; i++) { + subprog = &obj->programs[i]; + if (!prog_is_subprog(obj, subprog)) + continue; + + subprog->sub_insn_off = 0; + for (j = 0; j < subprog->nr_reloc; j++) + if (subprog->reloc_desc[j].type == RELO_CALL) + subprog->reloc_desc[j].processed = false; + } + + err = bpf_object__reloc_code(obj, prog, prog); + if (err) + return err; + + return 0; } @@ -5880,37 +6108,45 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) return err; } } - /* ensure .text is relocated first, as it's going to be copied as-is - * later for sub-program calls + /* relocate data references first for all programs and sub-programs, + * as they don't change relative to code locations, so subsequent + * subprogram processing won't need to re-calculate any of them */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (prog->sec_idx != obj->efile.text_shndx) - continue; - - err = bpf_program__relocate(prog, obj); + err = bpf_object__relocate_data(obj, prog); if (err) { pr_warn("prog '%s': failed to relocate data references: %d\n", prog->name, err); return err; } - break; } - /* now relocate everything but .text, which by now is relocated - * properly, so we can copy raw sub-program instructions as is safely + /* now relocate subprogram calls and append used subprograms to main + * programs; each copy of subprogram code needs to be relocated + * differently for each main program, because its code location might + * have changed */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (prog->sec_idx == obj->efile.text_shndx) + /* sub-program's sub-calls are relocated within the context of + * its main program only + */ + if (prog_is_subprog(obj, prog)) continue; - err = bpf_program__relocate(prog, obj); + err = bpf_object__relocate_calls(obj, prog); if (err) { pr_warn("prog '%s': failed to relocate calls: %d\n", prog->name, err); return err; } } + /* free up relocation descriptors */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + zfree(&prog->reloc_desc); + prog->nr_reloc = 0; + } return 0; } @@ -6030,41 +6266,53 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, return 0; } -static int bpf_object__collect_reloc(struct bpf_object *obj) +static int cmp_relocs(const void *_a, const void *_b) { - int i, err; + const struct reloc_desc *a = _a; + const struct reloc_desc *b = _b; - if (!obj_elf_valid(obj)) { - pr_warn("Internal error: elf object is closed\n"); - return -LIBBPF_ERRNO__INTERNAL; - } + if (a->insn_idx != b->insn_idx) + return a->insn_idx < b->insn_idx ? -1 : 1; + + /* no two relocations should have the same insn_idx, but ... */ + if (a->type != b->type) + return a->type < b->type ? -1 : 1; + + return 0; +} + +static int bpf_object__collect_relos(struct bpf_object *obj) +{ + int i, err; for (i = 0; i < obj->efile.nr_reloc_sects; i++) { GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr; Elf_Data *data = obj->efile.reloc_sects[i].data; int idx = shdr->sh_info; - struct bpf_program *prog; if (shdr->sh_type != SHT_REL) { pr_warn("internal error at %d\n", __LINE__); return -LIBBPF_ERRNO__INTERNAL; } - if (idx == obj->efile.st_ops_shndx) { + if (idx == obj->efile.st_ops_shndx) err = bpf_object__collect_st_ops_relos(obj, shdr, data); - } else if (idx == obj->efile.btf_maps_shndx) { + else if (idx == obj->efile.btf_maps_shndx) err = bpf_object__collect_map_relos(obj, shdr, data); - } else { - prog = bpf_object__find_prog_by_idx(obj, idx); - if (!prog) { - pr_warn("relocation failed: no prog in section(%d)\n", idx); - return -LIBBPF_ERRNO__RELOC; - } - err = bpf_program__collect_reloc(prog, shdr, data, obj); - } + else + err = bpf_object__collect_prog_relos(obj, shdr, data); if (err) return err; } + + for (i = 0; i < obj->nr_programs; i++) { + struct bpf_program *p = &obj->programs[i]; + + if (!p->nr_reloc) + continue; + + qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs); + } return 0; } @@ -6314,12 +6562,6 @@ out: return err; } -static bool bpf_program__is_function_storage(const struct bpf_program *prog, - const struct bpf_object *obj) -{ - return prog->sec_idx == obj->efile.text_shndx && obj->has_pseudo_calls; -} - static int bpf_object__load_progs(struct bpf_object *obj, int log_level) { @@ -6336,7 +6578,7 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level) for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (bpf_program__is_function_storage(prog, obj)) + if (prog_is_subprog(obj, prog)) continue; if (!prog->load) { pr_debug("prog '%s': skipped loading\n", prog->name); @@ -6400,7 +6642,7 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, err = err ? : bpf_object__collect_externs(obj); err = err ? : bpf_object__finalize_btf(obj); err = err ? : bpf_object__init_maps(obj, opts); - err = err ? : bpf_object__collect_reloc(obj); + err = err ? : bpf_object__collect_relos(obj); if (err) goto out; bpf_object__elf_finish(obj); @@ -7404,7 +7646,7 @@ bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj) do { prog = __bpf_program__iter(prog, obj, true); - } while (prog && bpf_program__is_function_storage(prog, obj)); + } while (prog && prog_is_subprog(obj, prog)); return prog; } @@ -7416,7 +7658,7 @@ bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj) do { prog = __bpf_program__iter(prog, obj, false); - } while (prog && bpf_program__is_function_storage(prog, obj)); + } while (prog && prog_is_subprog(obj, prog)); return prog; } -- cgit v1.2.3 From 8505e8709b5eedb7c662354e8436a2a164181109 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:33 -0700 Subject: libbpf: Implement generalized .BTF.ext func/line info adjustment Complete multi-prog sections and multi sub-prog support in libbpf by properly adjusting .BTF.ext's line and function information. Mark exposed btf_ext__reloc_func_info() and btf_ext__reloc_func_info() APIs as deprecated. These APIs have simplistic assumption that all sub-programs are going to be appended to all main BPF programs, which doesn't hold in real life. It's unlikely there are any users of this API, as it's very libbpf internals-specific. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200903203542.15944-6-andriin@fb.com --- tools/lib/bpf/btf.h | 18 ++-- tools/lib/bpf/libbpf.c | 217 +++++++++++++++++++++++++++--------------- tools/lib/bpf/libbpf_common.h | 2 + 3 files changed, 153 insertions(+), 84 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 91f0ad0e0325..2a55320d87d0 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -57,14 +57,16 @@ LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size); -LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf, - const struct btf_ext *btf_ext, - const char *sec_name, __u32 insns_cnt, - void **func_info, __u32 *cnt); -LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf, - const struct btf_ext *btf_ext, - const char *sec_name, __u32 insns_cnt, - void **line_info, __u32 *cnt); +LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_func_info was never meant as a public API and has wrong assumptions embedded in it; it will be removed in the future libbpf versions") +int btf_ext__reloc_func_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **func_info, __u32 *cnt); +LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_line_info was never meant as a public API and has wrong assumptions embedded in it; it will be removed in the future libbpf versions") +int btf_ext__reloc_line_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **line_info, __u32 *cnt); LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4e32a1028379..ca2b5c9145da 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4241,75 +4241,6 @@ err_out: return err; } -static int -check_btf_ext_reloc_err(struct bpf_program *prog, int err, - void *btf_prog_info, const char *info_name) -{ - if (err != -ENOENT) { - pr_warn("Error in loading %s for sec %s.\n", - info_name, prog->section_name); - return err; - } - - /* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */ - - if (btf_prog_info) { - /* - * Some info has already been found but has problem - * in the last btf_ext reloc. Must have to error out. - */ - pr_warn("Error in relocating %s for sec %s.\n", - info_name, prog->section_name); - return err; - } - - /* Have problem loading the very first info. Ignore the rest. */ - pr_warn("Cannot find %s for main program sec %s. Ignore all %s.\n", - info_name, prog->section_name, info_name); - return 0; -} - -static int -bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj, - const char *section_name, __u32 insn_offset) -{ - int err; - - if (!insn_offset || prog->func_info) { - /* - * !insn_offset => main program - * - * For sub prog, the main program's func_info has to - * be loaded first (i.e. prog->func_info != NULL) - */ - err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext, - section_name, insn_offset, - &prog->func_info, - &prog->func_info_cnt); - if (err) - return check_btf_ext_reloc_err(prog, err, - prog->func_info, - "bpf_func_info"); - - prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext); - } - - if (!insn_offset || prog->line_info) { - err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext, - section_name, insn_offset, - &prog->line_info, - &prog->line_info_cnt); - if (err) - return check_btf_ext_reloc_err(prog, err, - prog->line_info, - "bpf_line_info"); - - prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext); - } - - return 0; -} - #define BPF_CORE_SPEC_MAX_LEN 64 /* represents BPF CO-RE field or array element accessor */ @@ -5855,6 +5786,147 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) return 0; } +static int adjust_prog_btf_ext_info(const struct bpf_object *obj, + const struct bpf_program *prog, + const struct btf_ext_info *ext_info, + void **prog_info, __u32 *prog_rec_cnt, + __u32 *prog_rec_sz) +{ + void *copy_start = NULL, *copy_end = NULL; + void *rec, *rec_end, *new_prog_info; + const struct btf_ext_info_sec *sec; + size_t old_sz, new_sz; + const char *sec_name; + int i, off_adj; + + for_each_btf_ext_sec(ext_info, sec) { + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (!sec_name) + return -EINVAL; + if (strcmp(sec_name, prog->section_name) != 0) + continue; + + for_each_btf_ext_rec(ext_info, sec, i, rec) { + __u32 insn_off = *(__u32 *)rec / BPF_INSN_SZ; + + if (insn_off < prog->sec_insn_off) + continue; + if (insn_off >= prog->sec_insn_off + prog->sec_insn_cnt) + break; + + if (!copy_start) + copy_start = rec; + copy_end = rec + ext_info->rec_size; + } + + if (!copy_start) + return -ENOENT; + + /* append func/line info of a given (sub-)program to the main + * program func/line info + */ + old_sz = (*prog_rec_cnt) * ext_info->rec_size; + new_sz = old_sz + (copy_end - copy_start); + new_prog_info = realloc(*prog_info, new_sz); + if (!new_prog_info) + return -ENOMEM; + *prog_info = new_prog_info; + *prog_rec_cnt = new_sz / ext_info->rec_size; + memcpy(new_prog_info + old_sz, copy_start, copy_end - copy_start); + + /* Kernel instruction offsets are in units of 8-byte + * instructions, while .BTF.ext instruction offsets generated + * by Clang are in units of bytes. So convert Clang offsets + * into kernel offsets and adjust offset according to program + * relocated position. + */ + off_adj = prog->sub_insn_off - prog->sec_insn_off; + rec = new_prog_info + old_sz; + rec_end = new_prog_info + new_sz; + for (; rec < rec_end; rec += ext_info->rec_size) { + __u32 *insn_off = rec; + + *insn_off = *insn_off / BPF_INSN_SZ + off_adj; + } + *prog_rec_sz = ext_info->rec_size; + return 0; + } + + return -ENOENT; +} + +static int +reloc_prog_func_and_line_info(const struct bpf_object *obj, + struct bpf_program *main_prog, + const struct bpf_program *prog) +{ + int err; + + /* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't + * supprot func/line info + */ + if (!obj->btf_ext || !kernel_supports(FEAT_BTF_FUNC)) + return 0; + + /* only attempt func info relocation if main program's func_info + * relocation was successful + */ + if (main_prog != prog && !main_prog->func_info) + goto line_info; + + err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->func_info, + &main_prog->func_info, + &main_prog->func_info_cnt, + &main_prog->func_info_rec_size); + if (err) { + if (err != -ENOENT) { + pr_warn("prog '%s': error relocating .BTF.ext function info: %d\n", + prog->name, err); + return err; + } + if (main_prog->func_info) { + /* + * Some info has already been found but has problem + * in the last btf_ext reloc. Must have to error out. + */ + pr_warn("prog '%s': missing .BTF.ext function info.\n", prog->name); + return err; + } + /* Have problem loading the very first info. Ignore the rest. */ + pr_warn("prog '%s': missing .BTF.ext function info for the main program, skipping all of .BTF.ext func info.\n", + prog->name); + } + +line_info: + /* don't relocate line info if main program's relocation failed */ + if (main_prog != prog && !main_prog->line_info) + return 0; + + err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->line_info, + &main_prog->line_info, + &main_prog->line_info_cnt, + &main_prog->line_info_rec_size); + if (err) { + if (err != -ENOENT) { + pr_warn("prog '%s': error relocating .BTF.ext line info: %d\n", + prog->name, err); + return err; + } + if (main_prog->line_info) { + /* + * Some info has already been found but has problem + * in the last btf_ext reloc. Must have to error out. + */ + pr_warn("prog '%s': missing .BTF.ext line info.\n", prog->name); + return err; + } + /* Have problem loading the very first info. Ignore the rest. */ + pr_warn("prog '%s': missing .BTF.ext line info for the main program, skipping all of .BTF.ext line info.\n", + prog->name); + } + return 0; +} + static int cmp_relo_by_insn_idx(const void *key, const void *elem) { size_t insn_idx = *(const size_t *)key; @@ -6064,13 +6136,6 @@ bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) struct bpf_program *subprog; int i, j, err; - if (obj->btf_ext) { - err = bpf_program_reloc_btf_ext(prog, obj, - prog->section_name, 0); - if (err) - return err; - } - /* mark all subprogs as not relocated (yet) within the context of * current main program */ diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h index a23ae1ac27eb..947d8bd8a7bb 100644 --- a/tools/lib/bpf/libbpf_common.h +++ b/tools/lib/bpf/libbpf_common.h @@ -15,6 +15,8 @@ #define LIBBPF_API __attribute__((visibility("default"))) #endif +#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg))) + /* Helper macro to declare and initialize libbpf options struct * * This dance with uninitialized declaration, followed by memset to zero, -- cgit v1.2.3 From 7e06aad52929d17610f28acd40dd10ed62295f85 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:34 -0700 Subject: libbpf: Add multi-prog section support for struct_ops Adjust struct_ops handling code to work with multi-program ELF sections properly. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200903203542.15944-7-andriin@fb.com --- tools/lib/bpf/libbpf.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ca2b5c9145da..2d6bf0af3305 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -73,8 +73,6 @@ #define __printf(a, b) __attribute__((format(printf, a, b))) static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); -static struct bpf_program *bpf_object__find_prog_by_idx(struct bpf_object *obj, - int idx); static const struct btf_type * skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); @@ -3249,20 +3247,6 @@ static int bpf_object__collect_externs(struct bpf_object *obj) return 0; } -static struct bpf_program * -bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx) -{ - struct bpf_program *prog; - size_t i; - - for (i = 0; i < obj->nr_programs; i++) { - prog = &obj->programs[i]; - if (prog->sec_idx == idx) - return prog; - } - return NULL; -} - struct bpf_program * bpf_object__find_program_by_title(const struct bpf_object *obj, const char *title) @@ -8198,7 +8182,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, const struct btf *btf; struct bpf_map *map; Elf_Data *symbols; - unsigned int moff; + unsigned int moff, insn_idx; const char *name; __u32 member_idx; GElf_Sym sym; @@ -8243,6 +8227,12 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, map->name, (size_t)rel.r_offset, shdr_idx); return -LIBBPF_ERRNO__RELOC; } + if (sym.st_value % BPF_INSN_SZ) { + pr_warn("struct_ops reloc %s: invalid target program offset %llu\n", + map->name, (__u64)sym.st_value); + return -LIBBPF_ERRNO__FORMAT; + } + insn_idx = sym.st_value / BPF_INSN_SZ; member = find_member_by_offset(st_ops->type, moff * 8); if (!member) { @@ -8259,7 +8249,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, return -EINVAL; } - prog = bpf_object__find_prog_by_idx(obj, shdr_idx); + prog = find_prog_by_sec_insn(obj, shdr_idx, insn_idx); if (!prog) { pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n", map->name, shdr_idx, name); -- cgit v1.2.3 From 52109584202783e90a83c95103307a9a03ba7d9e Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 13:35:38 -0700 Subject: libbpf: Deprecate notion of BPF program "title" in favor of "section name" BPF program title is ambigious and misleading term. It is ELF section name, so let's just call it that and deprecate bpf_program__title() API in favor of bpf_program__section_name(). Additionally, using bpf_object__find_program_by_title() is now inherently dangerous and ambiguous, as multiple BPF program can have the same section name. So deprecate this API as well and recommend to switch to non-ambiguous bpf_object__find_program_by_name(). Internally, clean up usage and mis-usage of BPF program section name for denoting BPF program name. Shorten the field name to prog->sec_name to be consistent with all other prog->sec_* variables. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200903203542.15944-11-andriin@fb.com --- tools/lib/bpf/libbpf.c | 215 +++++++++++++++++++++-------------------------- tools/lib/bpf/libbpf.h | 5 +- tools/lib/bpf/libbpf.map | 1 + 3 files changed, 101 insertions(+), 120 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2d6bf0af3305..47b43c13eee5 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -217,7 +217,7 @@ struct bpf_sec_def { */ struct bpf_program { const struct bpf_sec_def *sec_def; - char *section_name; + char *sec_name; size_t sec_idx; /* this program's instruction offset (in number of instructions) * within its containing ELF section @@ -239,7 +239,7 @@ struct bpf_program { size_t sub_insn_off; char *name; - /* section_name with / replaced by _; makes recursive pinning + /* sec_name with / replaced by _; makes recursive pinning * in bpf_object__pin_programs easier */ char *pin_name; @@ -515,7 +515,7 @@ static void bpf_program__exit(struct bpf_program *prog) bpf_program__unload(prog); zfree(&prog->name); - zfree(&prog->section_name); + zfree(&prog->sec_name); zfree(&prog->pin_name); zfree(&prog->insns); zfree(&prog->reloc_desc); @@ -529,7 +529,7 @@ static char *__bpf_program__pin_name(struct bpf_program *prog) { char *name, *p; - name = p = strdup(prog->section_name); + name = p = strdup(prog->sec_name); while ((p = strchr(p, '/'))) *p = '_'; @@ -574,8 +574,8 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, prog->instances.fds = NULL; prog->instances.nr = -1; - prog->section_name = strdup(sec_name); - if (!prog->section_name) + prog->sec_name = strdup(sec_name); + if (!prog->sec_name) goto errout; prog->name = strdup(name); @@ -3254,7 +3254,7 @@ bpf_object__find_program_by_title(const struct bpf_object *obj, struct bpf_program *pos; bpf_object__for_each_program(pos, obj) { - if (pos->section_name && !strcmp(pos->section_name, title)) + if (pos->sec_name && !strcmp(pos->sec_name, title)) return pos; } return NULL; @@ -4994,8 +4994,7 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, *val = sz; } else { pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n", - bpf_program__title(prog, false), - relo->kind, relo->insn_off / 8); + prog->name, relo->kind, relo->insn_off / 8); return -EINVAL; } if (validate) @@ -5017,8 +5016,7 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, if (byte_sz >= 8) { /* bitfield can't be read with 64-bit read */ pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n", - bpf_program__title(prog, false), - relo->kind, relo->insn_off / 8); + prog->name, relo->kind, relo->insn_off / 8); return -E2BIG; } byte_sz *= 2; @@ -5183,8 +5181,8 @@ static int bpf_core_calc_relo(const struct bpf_program *prog, } else if (err == -EOPNOTSUPP) { /* EOPNOTSUPP means unknown/unsupported relocation */ pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%d) at insn #%d\n", - bpf_program__title(prog, false), relo_idx, - core_relo_kind_str(relo->kind), relo->kind, relo->insn_off / 8); + prog->name, relo_idx, core_relo_kind_str(relo->kind), + relo->kind, relo->insn_off / 8); } return err; @@ -5198,7 +5196,7 @@ static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, int insn_idx, struct bpf_insn *insn) { pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n", - bpf_program__title(prog, false), relo_idx, insn_idx); + prog->name, relo_idx, insn_idx); insn->code = BPF_JMP | BPF_CALL; insn->dst_reg = 0; insn->src_reg = 0; @@ -5270,14 +5268,14 @@ static int bpf_core_patch_insn(struct bpf_program *prog, return -EINVAL; if (res->validate && insn->imm != orig_val) { pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n", - bpf_program__title(prog, false), relo_idx, + prog->name, relo_idx, insn_idx, insn->imm, orig_val, new_val); return -EINVAL; } orig_val = insn->imm; insn->imm = new_val; pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n", - bpf_program__title(prog, false), relo_idx, insn_idx, + prog->name, relo_idx, insn_idx, orig_val, new_val); break; case BPF_LDX: @@ -5285,21 +5283,18 @@ static int bpf_core_patch_insn(struct bpf_program *prog, case BPF_STX: if (res->validate && insn->off != orig_val) { pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n", - bpf_program__title(prog, false), relo_idx, - insn_idx, insn->off, orig_val, new_val); + prog->name, relo_idx, insn_idx, insn->off, orig_val, new_val); return -EINVAL; } if (new_val > SHRT_MAX) { pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n", - bpf_program__title(prog, false), relo_idx, - insn_idx, new_val); + prog->name, relo_idx, insn_idx, new_val); return -ERANGE; } orig_val = insn->off; insn->off = new_val; pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n", - bpf_program__title(prog, false), relo_idx, insn_idx, - orig_val, new_val); + prog->name, relo_idx, insn_idx, orig_val, new_val); break; case BPF_LD: { __u64 imm; @@ -5310,14 +5305,14 @@ static int bpf_core_patch_insn(struct bpf_program *prog, insn[1].code != 0 || insn[1].dst_reg != 0 || insn[1].src_reg != 0 || insn[1].off != 0) { pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n", - bpf_program__title(prog, false), relo_idx, insn_idx); + prog->name, relo_idx, insn_idx); return -EINVAL; } imm = insn[0].imm + ((__u64)insn[1].imm << 32); if (res->validate && imm != orig_val) { pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n", - bpf_program__title(prog, false), relo_idx, + prog->name, relo_idx, insn_idx, (unsigned long long)imm, orig_val, new_val); return -EINVAL; @@ -5326,15 +5321,14 @@ static int bpf_core_patch_insn(struct bpf_program *prog, insn[0].imm = new_val; insn[1].imm = 0; /* currently only 32-bit values are supported */ pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n", - bpf_program__title(prog, false), relo_idx, insn_idx, + prog->name, relo_idx, insn_idx, (unsigned long long)imm, new_val); break; } default: pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n", - bpf_program__title(prog, false), relo_idx, - insn_idx, insn->code, insn->src_reg, insn->dst_reg, - insn->off, insn->imm); + prog->name, relo_idx, insn_idx, insn->code, + insn->src_reg, insn->dst_reg, insn->off, insn->imm); return -EINVAL; } @@ -5464,7 +5458,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog, const struct btf *targ_btf, struct hashmap *cand_cache) { - const char *prog_name = bpf_program__title(prog, false); struct bpf_core_spec local_spec, cand_spec, targ_spec = {}; const void *type_key = u32_as_hash_key(relo->type_id); struct bpf_core_relo_res cand_res, targ_res; @@ -5491,13 +5484,13 @@ static int bpf_core_apply_relo(struct bpf_program *prog, err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec); if (err) { pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n", - prog_name, relo_idx, local_id, btf_kind_str(local_type), + prog->name, relo_idx, local_id, btf_kind_str(local_type), str_is_empty(local_name) ? "" : local_name, spec_str, err); return -EINVAL; } - pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog_name, + pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog->name, relo_idx, core_relo_kind_str(relo->kind), relo->kind); bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec); libbpf_print(LIBBPF_DEBUG, "\n"); @@ -5514,7 +5507,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, /* libbpf doesn't support candidate search for anonymous types */ if (str_is_empty(spec_str)) { pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n", - prog_name, relo_idx, core_relo_kind_str(relo->kind), relo->kind); + prog->name, relo_idx, core_relo_kind_str(relo->kind), relo->kind); return -EOPNOTSUPP; } @@ -5522,7 +5515,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf); if (IS_ERR(cand_ids)) { pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld", - prog_name, relo_idx, local_id, btf_kind_str(local_type), + prog->name, relo_idx, local_id, btf_kind_str(local_type), local_name, PTR_ERR(cand_ids)); return PTR_ERR(cand_ids); } @@ -5538,13 +5531,13 @@ static int bpf_core_apply_relo(struct bpf_program *prog, err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec); if (err < 0) { pr_warn("prog '%s': relo #%d: error matching candidate #%d ", - prog_name, relo_idx, i); + prog->name, relo_idx, i); bpf_core_dump_spec(LIBBPF_WARN, &cand_spec); libbpf_print(LIBBPF_WARN, ": %d\n", err); return err; } - pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog_name, + pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog->name, relo_idx, err == 0 ? "non-matching" : "matching", i); bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec); libbpf_print(LIBBPF_DEBUG, "\n"); @@ -5564,7 +5557,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, * should all resolve to the same bit offset */ pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n", - prog_name, relo_idx, cand_spec.bit_offset, + prog->name, relo_idx, cand_spec.bit_offset, targ_spec.bit_offset); return -EINVAL; } else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) { @@ -5573,7 +5566,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, * proceed due to ambiguity */ pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n", - prog_name, relo_idx, + prog->name, relo_idx, cand_res.poison ? "failure" : "success", cand_res.new_val, targ_res.poison ? "failure" : "success", targ_res.new_val); return -EINVAL; @@ -5606,7 +5599,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, */ if (j == 0) { pr_debug("prog '%s': relo #%d: no matching targets found\n", - prog_name, relo_idx); + prog->name, relo_idx); /* calculate single target relo result explicitly */ err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, NULL, &targ_res); @@ -5619,7 +5612,7 @@ patch_insn: err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n", - prog_name, relo_idx, relo->insn_off, err); + prog->name, relo_idx, relo->insn_off, err); return -EINVAL; } @@ -5673,7 +5666,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) prog = NULL; for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; - if (strcmp(prog->section_name, sec_name) == 0) + if (strcmp(prog->sec_name, sec_name) == 0) break; } if (!prog) { @@ -5787,7 +5780,7 @@ static int adjust_prog_btf_ext_info(const struct bpf_object *obj, sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); if (!sec_name) return -EINVAL; - if (strcmp(sec_name, prog->section_name) != 0) + if (strcmp(sec_name, prog->sec_name) != 0) continue; for_each_btf_ext_rec(ext_info, sec, i, rec) { @@ -6527,8 +6520,7 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) int err = 0, fd, i, btf_id; if (prog->obj->loaded) { - pr_warn("prog '%s'('%s'): can't load after object was loaded\n", - prog->name, prog->section_name); + pr_warn("prog '%s': can't load after object was loaded\n", prog->name); return -EINVAL; } @@ -6544,7 +6536,7 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) if (prog->instances.nr < 0 || !prog->instances.fds) { if (prog->preprocessor) { pr_warn("Internal error: can't load program '%s'\n", - prog->section_name); + prog->name); return -LIBBPF_ERRNO__INTERNAL; } @@ -6559,8 +6551,8 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) if (!prog->preprocessor) { if (prog->instances.nr != 1) { - pr_warn("Program '%s' is inconsistent: nr(%d) != 1\n", - prog->section_name, prog->instances.nr); + pr_warn("prog '%s': inconsistent nr(%d) != 1\n", + prog->name, prog->instances.nr); } err = load_program(prog, prog->insns, prog->insns_cnt, license, kern_ver, &fd); @@ -6578,13 +6570,13 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) prog->insns_cnt, &result); if (err) { pr_warn("Preprocessing the %dth instance of program '%s' failed\n", - i, prog->section_name); + i, prog->name); goto out; } if (!result.new_insn_ptr || !result.new_insn_cnt) { pr_debug("Skip loading the %dth instance of program '%s'\n", - i, prog->section_name); + i, prog->name); prog->instances.fds[i] = -1; if (result.pfd) *result.pfd = -1; @@ -6595,7 +6587,7 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) result.new_insn_cnt, license, kern_ver, &fd); if (err) { pr_warn("Loading the %dth instance of program '%s' failed\n", - i, prog->section_name); + i, prog->name); goto out; } @@ -6605,7 +6597,7 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) } out: if (err) - pr_warn("failed to load program '%s'\n", prog->section_name); + pr_warn("failed to load program '%s'\n", prog->name); zfree(&prog->insns); prog->insns_cnt = 0; return err; @@ -6697,7 +6689,7 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, bpf_object__elf_finish(obj); bpf_object__for_each_program(prog, obj) { - prog->sec_def = find_sec_def(prog->section_name); + prog->sec_def = find_sec_def(prog->sec_name); if (!prog->sec_def) /* couldn't guess, but user might manually specify */ continue; @@ -7078,7 +7070,7 @@ int bpf_program__pin_instance(struct bpf_program *prog, const char *path, if (instance < 0 || instance >= prog->instances.nr) { pr_warn("invalid prog instance %d of prog %s (max %d)\n", - instance, prog->section_name, prog->instances.nr); + instance, prog->name, prog->instances.nr); return -EINVAL; } @@ -7109,7 +7101,7 @@ int bpf_program__unpin_instance(struct bpf_program *prog, const char *path, if (instance < 0 || instance >= prog->instances.nr) { pr_warn("invalid prog instance %d of prog %s (max %d)\n", - instance, prog->section_name, prog->instances.nr); + instance, prog->name, prog->instances.nr); return -EINVAL; } @@ -7139,8 +7131,7 @@ int bpf_program__pin(struct bpf_program *prog, const char *path) } if (prog->instances.nr <= 0) { - pr_warn("no instances of prog %s to pin\n", - prog->section_name); + pr_warn("no instances of prog %s to pin\n", prog->name); return -EINVAL; } @@ -7202,8 +7193,7 @@ int bpf_program__unpin(struct bpf_program *prog, const char *path) } if (prog->instances.nr <= 0) { - pr_warn("no instances of prog %s to pin\n", - prog->section_name); + pr_warn("no instances of prog %s to pin\n", prog->name); return -EINVAL; } @@ -7738,11 +7728,16 @@ const char *bpf_program__name(const struct bpf_program *prog) return prog->name; } +const char *bpf_program__section_name(const struct bpf_program *prog) +{ + return prog->sec_name; +} + const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy) { const char *title; - title = prog->section_name; + title = prog->sec_name; if (needs_copy) { title = strdup(title); if (!title) { @@ -7815,14 +7810,14 @@ int bpf_program__nth_fd(const struct bpf_program *prog, int n) if (n >= prog->instances.nr || n < 0) { pr_warn("Can't get the %dth fd from program %s: only %d instances\n", - n, prog->section_name, prog->instances.nr); + n, prog->name, prog->instances.nr); return -EINVAL; } fd = prog->instances.fds[n]; if (fd < 0) { pr_warn("%dth instance of program '%s' is invalid\n", - n, prog->section_name); + n, prog->name); return -ENOENT; } @@ -8259,7 +8254,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, if (prog->type == BPF_PROG_TYPE_UNSPEC) { const struct bpf_sec_def *sec_def; - sec_def = find_sec_def(prog->section_name); + sec_def = find_sec_def(prog->sec_name); if (sec_def && sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) { /* for pr_warn */ @@ -8282,7 +8277,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, invalid_prog: pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n", - map->name, prog->name, prog->section_name, prog->type, + map->name, prog->name, prog->sec_name, prog->type, prog->attach_btf_id, prog->expected_attach_type, name); return -EINVAL; } @@ -8386,7 +8381,7 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog) { enum bpf_attach_type attach_type = prog->expected_attach_type; __u32 attach_prog_fd = prog->attach_prog_fd; - const char *name = prog->section_name; + const char *name = prog->sec_name; int i, err; if (!name) @@ -8913,14 +8908,14 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int prog_fd, err; if (pfd < 0) { - pr_warn("program '%s': invalid perf event FD %d\n", - bpf_program__title(prog, false), pfd); + pr_warn("prog '%s': invalid perf event FD %d\n", + prog->name, pfd); return ERR_PTR(-EINVAL); } prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { - pr_warn("program '%s': can't attach BPF program w/o FD (did you load it?)\n", - bpf_program__title(prog, false)); + pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", + prog->name); return ERR_PTR(-EINVAL); } @@ -8933,20 +8928,18 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) { err = -errno; free(link); - pr_warn("program '%s': failed to attach to pfd %d: %s\n", - bpf_program__title(prog, false), pfd, - libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + pr_warn("prog '%s': failed to attach to pfd %d: %s\n", + prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); if (err == -EPROTO) - pr_warn("program '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n", - bpf_program__title(prog, false), pfd); + pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n", + prog->name, pfd); return ERR_PTR(err); } if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { err = -errno; free(link); - pr_warn("program '%s': failed to enable pfd %d: %s\n", - bpf_program__title(prog, false), pfd, - libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + pr_warn("prog '%s': failed to enable pfd %d: %s\n", + prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return ERR_PTR(err); } return link; @@ -9068,9 +9061,8 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog, pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name, 0 /* offset */, -1 /* pid */); if (pfd < 0) { - pr_warn("program '%s': failed to create %s '%s' perf event: %s\n", - bpf_program__title(prog, false), - retprobe ? "kretprobe" : "kprobe", func_name, + pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", func_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return ERR_PTR(pfd); } @@ -9078,9 +9070,8 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog, if (IS_ERR(link)) { close(pfd); err = PTR_ERR(link); - pr_warn("program '%s': failed to attach to %s '%s': %s\n", - bpf_program__title(prog, false), - retprobe ? "kretprobe" : "kprobe", func_name, + pr_warn("prog '%s': failed to attach to %s '%s': %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", func_name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return link; } @@ -9093,7 +9084,7 @@ static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec, const char *func_name; bool retprobe; - func_name = bpf_program__title(prog, false) + sec->len; + func_name = prog->sec_name + sec->len; retprobe = strcmp(sec->sec, "kretprobe/") == 0; return bpf_program__attach_kprobe(prog, retprobe, func_name); @@ -9111,9 +9102,8 @@ struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog, pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path, func_offset, pid); if (pfd < 0) { - pr_warn("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n", - bpf_program__title(prog, false), - retprobe ? "uretprobe" : "uprobe", + pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n", + prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return ERR_PTR(pfd); @@ -9122,9 +9112,8 @@ struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog, if (IS_ERR(link)) { close(pfd); err = PTR_ERR(link); - pr_warn("program '%s': failed to attach to %s '%s:0x%zx': %s\n", - bpf_program__title(prog, false), - retprobe ? "uretprobe" : "uprobe", + pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n", + prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return link; @@ -9192,9 +9181,8 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, pfd = perf_event_open_tracepoint(tp_category, tp_name); if (pfd < 0) { - pr_warn("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n", - bpf_program__title(prog, false), - tp_category, tp_name, + pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n", + prog->name, tp_category, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return ERR_PTR(pfd); } @@ -9202,9 +9190,8 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, if (IS_ERR(link)) { close(pfd); err = PTR_ERR(link); - pr_warn("program '%s': failed to attach to tracepoint '%s/%s': %s\n", - bpf_program__title(prog, false), - tp_category, tp_name, + pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n", + prog->name, tp_category, tp_name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return link; } @@ -9217,7 +9204,7 @@ static struct bpf_link *attach_tp(const struct bpf_sec_def *sec, char *sec_name, *tp_cat, *tp_name; struct bpf_link *link; - sec_name = strdup(bpf_program__title(prog, false)); + sec_name = strdup(prog->sec_name); if (!sec_name) return ERR_PTR(-ENOMEM); @@ -9246,8 +9233,7 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { - pr_warn("program '%s': can't attach before loaded\n", - bpf_program__title(prog, false)); + pr_warn("prog '%s': can't attach before loaded\n", prog->name); return ERR_PTR(-EINVAL); } @@ -9260,9 +9246,8 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, if (pfd < 0) { pfd = -errno; free(link); - pr_warn("program '%s': failed to attach to raw tracepoint '%s': %s\n", - bpf_program__title(prog, false), tp_name, - libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n", + prog->name, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return ERR_PTR(pfd); } link->fd = pfd; @@ -9272,7 +9257,7 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec, struct bpf_program *prog) { - const char *tp_name = bpf_program__title(prog, false) + sec->len; + const char *tp_name = prog->sec_name + sec->len; return bpf_program__attach_raw_tracepoint(prog, tp_name); } @@ -9286,8 +9271,7 @@ static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog) prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { - pr_warn("program '%s': can't attach before loaded\n", - bpf_program__title(prog, false)); + pr_warn("prog '%s': can't attach before loaded\n", prog->name); return ERR_PTR(-EINVAL); } @@ -9300,9 +9284,8 @@ static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog) if (pfd < 0) { pfd = -errno; free(link); - pr_warn("program '%s': failed to attach: %s\n", - bpf_program__title(prog, false), - libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + pr_warn("prog '%s': failed to attach: %s\n", + prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return ERR_PTR(pfd); } link->fd = pfd; @@ -9348,8 +9331,7 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd, prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { - pr_warn("program '%s': can't attach before loaded\n", - bpf_program__title(prog, false)); + pr_warn("prog '%s': can't attach before loaded\n", prog->name); return ERR_PTR(-EINVAL); } @@ -9363,8 +9345,8 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd, if (link_fd < 0) { link_fd = -errno; free(link); - pr_warn("program '%s': failed to attach to %s: %s\n", - bpf_program__title(prog, false), target_name, + pr_warn("prog '%s': failed to attach to %s: %s\n", + prog->name, target_name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); return ERR_PTR(link_fd); } @@ -9408,8 +9390,7 @@ bpf_program__attach_iter(struct bpf_program *prog, prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { - pr_warn("program '%s': can't attach before loaded\n", - bpf_program__title(prog, false)); + pr_warn("prog '%s': can't attach before loaded\n", prog->name); return ERR_PTR(-EINVAL); } @@ -9423,9 +9404,8 @@ bpf_program__attach_iter(struct bpf_program *prog, if (link_fd < 0) { link_fd = -errno; free(link); - pr_warn("program '%s': failed to attach to iterator: %s\n", - bpf_program__title(prog, false), - libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + pr_warn("prog '%s': failed to attach to iterator: %s\n", + prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); return ERR_PTR(link_fd); } link->fd = link_fd; @@ -9436,7 +9416,7 @@ struct bpf_link *bpf_program__attach(struct bpf_program *prog) { const struct bpf_sec_def *sec_def; - sec_def = find_sec_def(bpf_program__title(prog, false)); + sec_def = find_sec_def(prog->sec_name); if (!sec_def || !sec_def->attach_fn) return ERR_PTR(-ESRCH); @@ -10506,12 +10486,11 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) struct bpf_program *prog = *s->progs[i].prog; struct bpf_link **link = s->progs[i].link; const struct bpf_sec_def *sec_def; - const char *sec_name = bpf_program__title(prog, false); if (!prog->load) continue; - sec_def = find_sec_def(sec_name); + sec_def = find_sec_def(prog->sec_name); if (!sec_def || !sec_def->attach_fn) continue; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 308e0ded8f14..a750f67a23f6 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -198,8 +198,9 @@ LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex); LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog); -LIBBPF_API const char *bpf_program__title(const struct bpf_program *prog, - bool needs_copy); +LIBBPF_API const char *bpf_program__section_name(const struct bpf_program *prog); +LIBBPF_API LIBBPF_DEPRECATED("BPF program title is confusing term; please use bpf_program__section_name() instead") +const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy); LIBBPF_API bool bpf_program__autoload(const struct bpf_program *prog); LIBBPF_API int bpf_program__set_autoload(struct bpf_program *prog, bool autoload); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 3fedcdc4ae2f..92ceb48a5ca2 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -302,6 +302,7 @@ LIBBPF_0.1.0 { LIBBPF_0.2.0 { global: + bpf_program__section_name; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; perf_buffer__epoll_fd; -- cgit v1.2.3 From 17e54b096e6a8dc92b92c59c2e3437550383b27a Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 21:16:10 -0700 Subject: libbpf: Fix another __u64 cast in printf Another issue of __u64 needing either %lu or %llu, depending on the architecture. Fix with cast to `unsigned long long`. Fixes: 7e06aad52929 ("libbpf: Add multi-prog section support for struct_ops") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200904041611.1695163-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 47b43c13eee5..53be32a2b9fc 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -8224,7 +8224,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, } if (sym.st_value % BPF_INSN_SZ) { pr_warn("struct_ops reloc %s: invalid target program offset %llu\n", - map->name, (__u64)sym.st_value); + map->name, (unsigned long long)sym.st_value); return -LIBBPF_ERRNO__FORMAT; } insn_idx = sym.st_value / BPF_INSN_SZ; -- cgit v1.2.3 From 8eb629585d2231e90112148009e2a11b0979ca38 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 3 Sep 2020 21:16:11 -0700 Subject: libbpf: Fix potential multiplication overflow Detected by LGTM static analyze in Github repo, fix potential multiplication overflow before result is casted to size_t. Fixes: 8505e8709b5e ("libbpf: Implement generalized .BTF.ext func/line info adjustment") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200904041611.1695163-2-andriin@fb.com --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 53be32a2b9fc..550950eb1860 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5802,7 +5802,7 @@ static int adjust_prog_btf_ext_info(const struct bpf_object *obj, /* append func/line info of a given (sub-)program to the main * program func/line info */ - old_sz = (*prog_rec_cnt) * ext_info->rec_size; + old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size; new_sz = old_sz + (copy_end - copy_start); new_prog_info = realloc(*prog_info, new_sz); if (!new_prog_info) -- cgit v1.2.3 From d317b0a8acfc4b126858e4cdadb03338d22f8ce0 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Mon, 14 Sep 2020 15:32:10 -0700 Subject: libbpf: Fix a compilation error with xsk.c for ubuntu 16.04 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When syncing latest libbpf repo to bcc, ubuntu 16.04 (4.4.0 LTS kernel) failed compilation for xsk.c: In file included from /tmp/debuild.0jkauG/bcc/src/cc/libbpf/src/xsk.c:23:0: /tmp/debuild.0jkauG/bcc/src/cc/libbpf/src/xsk.c: In function ‘xsk_get_ctx’: /tmp/debuild.0jkauG/bcc/src/cc/libbpf/include/linux/list.h:81:9: warning: implicit declaration of function ‘container_of’ [-Wimplicit-function-declaration] container_of(ptr, type, member) ^ /tmp/debuild.0jkauG/bcc/src/cc/libbpf/include/linux/list.h:83:9: note: in expansion of macro ‘list_entry’ list_entry((ptr)->next, type, member) ... src/cc/CMakeFiles/bpf-static.dir/build.make:209: recipe for target 'src/cc/CMakeFiles/bpf-static.dir/libbpf/src/xsk.c.o' failed Commit 2f6324a3937f ("libbpf: Support shared umems between queues and devices") added include file , which uses macro "container_of". xsk.c file also includes before . In a more recent distro kernel, includes which contains the macro definition for "container_of". So compilation is all fine. But in ubuntu 16.04 kernel, does not contain which caused the above compilation error. Let explicitly add in xsk.c to avoid compilation error in old distro's. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20200914223210.1831262-1-yhs@fb.com --- tools/lib/bpf/xsk.c | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 49c324594792..30b4ca5d2ac7 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include -- cgit v1.2.3 From 5d23328dccd93c47e2719cb9d2ae303c235d277d Mon Sep 17 00:00:00 2001 From: YiFei Zhu Date: Tue, 15 Sep 2020 16:45:41 -0700 Subject: libbpf: Add BPF_PROG_BIND_MAP syscall and use it on .rodata section The patch adds a simple wrapper bpf_prog_bind_map around the syscall. When the libbpf tries to load a program, it will probe the kernel for the support of this syscall and unconditionally bind .rodata section to the program. Signed-off-by: YiFei Zhu Signed-off-by: Stanislav Fomichev Signed-off-by: Alexei Starovoitov Cc: YiFei Zhu Link: https://lore.kernel.org/bpf/20200915234543.3220146-4-sdf@google.com --- tools/lib/bpf/bpf.c | 16 +++++++++++ tools/lib/bpf/bpf.h | 8 ++++++ tools/lib/bpf/libbpf.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.map | 1 + 4 files changed, 94 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 82b983ff6569..2baa1308737c 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -872,3 +872,19 @@ int bpf_enable_stats(enum bpf_stats_type type) return sys_bpf(BPF_ENABLE_STATS, &attr, sizeof(attr)); } + +int bpf_prog_bind_map(int prog_fd, int map_fd, + const struct bpf_prog_bind_opts *opts) +{ + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_prog_bind_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.prog_bind_map.prog_fd = prog_fd; + attr.prog_bind_map.map_fd = map_fd; + attr.prog_bind_map.flags = OPTS_GET(opts, flags, 0); + + return sys_bpf(BPF_PROG_BIND_MAP, &attr, sizeof(attr)); +} diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 015d13f25fcc..8c1ac4b42f90 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -243,6 +243,14 @@ LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, enum bpf_stats_type; /* defined in up-to-date linux/bpf.h */ LIBBPF_API int bpf_enable_stats(enum bpf_stats_type type); +struct bpf_prog_bind_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u32 flags; +}; +#define bpf_prog_bind_opts__last_field flags + +LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd, + const struct bpf_prog_bind_opts *opts); #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 550950eb1860..570235dbc922 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -174,6 +174,8 @@ enum kern_feature_id { FEAT_EXP_ATTACH_TYPE, /* bpf_probe_read_{kernel,user}[_str] helpers */ FEAT_PROBE_READ_KERN, + /* BPF_PROG_BIND_MAP is supported */ + FEAT_PROG_BIND_MAP, __FEAT_CNT, }; @@ -409,6 +411,7 @@ struct bpf_object { struct extern_desc *externs; int nr_extern; int kconfig_map_idx; + int rodata_map_idx; bool loaded; bool has_subcalls; @@ -1070,6 +1073,7 @@ static struct bpf_object *bpf_object__new(const char *path, obj->efile.bss_shndx = -1; obj->efile.st_ops_shndx = -1; obj->kconfig_map_idx = -1; + obj->rodata_map_idx = -1; obj->kern_version = get_kernel_version(); obj->loaded = false; @@ -1428,6 +1432,8 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj) obj->efile.rodata->d_size); if (err) return err; + + obj->rodata_map_idx = obj->nr_maps - 1; } if (obj->efile.bss_shndx >= 0) { err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, @@ -3894,6 +3900,52 @@ static int probe_kern_probe_read_kernel(void) return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); } +static int probe_prog_bind_map(void) +{ + struct bpf_load_program_attr prg_attr; + struct bpf_create_map_attr map_attr; + char *cp, errmsg[STRERR_BUFSIZE]; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret, map, prog; + + memset(&map_attr, 0, sizeof(map_attr)); + map_attr.map_type = BPF_MAP_TYPE_ARRAY; + map_attr.key_size = sizeof(int); + map_attr.value_size = 32; + map_attr.max_entries = 1; + + map = bpf_create_map_xattr(&map_attr); + if (map < 0) { + ret = -errno; + cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); + pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", + __func__, cp, -ret); + return ret; + } + + memset(&prg_attr, 0, sizeof(prg_attr)); + prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + prg_attr.insns = insns; + prg_attr.insns_cnt = ARRAY_SIZE(insns); + prg_attr.license = "GPL"; + + prog = bpf_load_program_xattr(&prg_attr, NULL, 0); + if (prog < 0) { + close(map); + return 0; + } + + ret = bpf_prog_bind_map(prog, map, NULL); + + close(map); + close(prog); + + return ret >= 0; +} + enum kern_feature_result { FEAT_UNKNOWN = 0, FEAT_SUPPORTED = 1, @@ -3934,6 +3986,9 @@ static struct kern_feature_desc { }, [FEAT_PROBE_READ_KERN] = { "bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel, + }, + [FEAT_PROG_BIND_MAP] = { + "BPF_PROG_BIND_MAP support", probe_prog_bind_map, } }; @@ -6468,6 +6523,20 @@ retry_load: if (ret >= 0) { if (log_buf && load_attr.log_level) pr_debug("verifier log:\n%s", log_buf); + + if (prog->obj->rodata_map_idx >= 0 && + kernel_supports(FEAT_PROG_BIND_MAP)) { + struct bpf_map *rodata_map = + &prog->obj->maps[prog->obj->rodata_map_idx]; + + if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': failed to bind .rodata map: %s\n", + prog->name, cp); + /* Don't fail hard if can't bind rodata. */ + } + } + *pfd = ret; ret = 0; goto out; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 92ceb48a5ca2..5f054dadf082 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -302,6 +302,7 @@ LIBBPF_0.1.0 { LIBBPF_0.2.0 { global: + bpf_prog_bind_map; bpf_program__section_name; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; -- cgit v1.2.3 From 88f7fe7233244101fa5b7786e2e298bf27fe1375 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Fri, 25 Sep 2020 13:54:30 -0700 Subject: libbpf: Support test run of raw tracepoint programs Add bpf_prog_test_run_opts() with support of new fields in bpf_attr.test, namely, flags and cpu. Also extend _opts operations to support outputs via opts. Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200925205432.1777-3-songliubraving@fb.com --- tools/lib/bpf/bpf.c | 31 +++++++++++++++++++++++++++++++ tools/lib/bpf/bpf.h | 26 ++++++++++++++++++++++++++ tools/lib/bpf/libbpf.map | 1 + tools/lib/bpf/libbpf_internal.h | 5 +++++ 4 files changed, 63 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 2baa1308737c..c5a4d8444bf6 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -712,6 +712,37 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr) return ret; } +int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts) +{ + union bpf_attr attr; + int ret; + + if (!OPTS_VALID(opts, bpf_test_run_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.test.prog_fd = prog_fd; + attr.test.cpu = OPTS_GET(opts, cpu, 0); + attr.test.flags = OPTS_GET(opts, flags, 0); + attr.test.repeat = OPTS_GET(opts, repeat, 0); + attr.test.duration = OPTS_GET(opts, duration, 0); + attr.test.ctx_size_in = OPTS_GET(opts, ctx_size_in, 0); + attr.test.ctx_size_out = OPTS_GET(opts, ctx_size_out, 0); + attr.test.data_size_in = OPTS_GET(opts, data_size_in, 0); + attr.test.data_size_out = OPTS_GET(opts, data_size_out, 0); + attr.test.ctx_in = ptr_to_u64(OPTS_GET(opts, ctx_in, NULL)); + attr.test.ctx_out = ptr_to_u64(OPTS_GET(opts, ctx_out, NULL)); + attr.test.data_in = ptr_to_u64(OPTS_GET(opts, data_in, NULL)); + attr.test.data_out = ptr_to_u64(OPTS_GET(opts, data_out, NULL)); + + ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr)); + OPTS_SET(opts, data_size_out, attr.test.data_size_out); + OPTS_SET(opts, ctx_size_out, attr.test.ctx_size_out); + OPTS_SET(opts, duration, attr.test.duration); + OPTS_SET(opts, retval, attr.test.retval); + return ret; +} + static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd) { union bpf_attr attr; diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 8c1ac4b42f90..4f3568e55527 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -251,6 +251,32 @@ struct bpf_prog_bind_opts { LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd, const struct bpf_prog_bind_opts *opts); + +struct bpf_test_run_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + const void *data_in; /* optional */ + void *data_out; /* optional */ + __u32 data_size_in; + __u32 data_size_out; /* in: max length of data_out + * out: length of data_out + */ + const void *ctx_in; /* optional */ + void *ctx_out; /* optional */ + __u32 ctx_size_in; + __u32 ctx_size_out; /* in: max length of ctx_out + * out: length of cxt_out + */ + __u32 retval; /* out: return code of the BPF program */ + int repeat; + __u32 duration; /* out: average per repetition in ns */ + __u32 flags; + __u32 cpu; +}; +#define bpf_test_run_opts__last_field cpu + +LIBBPF_API int bpf_prog_test_run_opts(int prog_fd, + struct bpf_test_run_opts *opts); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 5f054dadf082..0623e7a99b1e 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -303,6 +303,7 @@ LIBBPF_0.1.0 { LIBBPF_0.2.0 { global: bpf_prog_bind_map; + bpf_prog_test_run_opts; bpf_program__section_name; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 4d1c366fca2c..d3f7a6a6bc98 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -136,6 +136,11 @@ static inline bool libbpf_validate_opts(const char *opts, ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) #define OPTS_GET(opts, field, fallback_value) \ (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) +#define OPTS_SET(opts, field, value) \ + do { \ + if (OPTS_HAS(opts, field)) \ + (opts)->field = value; \ + } while (0) int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); -- cgit v1.2.3 From 740e69c3c511aa207155ba993a854b5bee79cdc2 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 25 Sep 2020 18:13:49 -0700 Subject: libbpf: Refactor internals of BTF type index Refactor implementation of internal BTF type index to not use direct pointers. Instead it uses offset relative to the start of types data section. This allows for types data to be reallocatable, enabling implementation of modifiable BTF. As now getting type by ID has an extra indirection step, convert all internal type lookups to a new helper btf_type_id(), that returns non-const pointer to a type by its ID. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200926011357.2366158-2-andriin@fb.com --- tools/lib/bpf/btf.c | 139 ++++++++++++++++++++++++++++------------------------ 1 file changed, 75 insertions(+), 64 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index a3d259e614b0..7c9957893ef2 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -31,11 +31,12 @@ struct btf { struct btf_header *hdr; void *data; }; - struct btf_type **types; + __u32 *type_offs; + __u32 type_offs_cap; const char *strings; void *nohdr_data; + void *types_data; __u32 nr_types; - __u32 types_size; __u32 data_size; int fd; int ptr_sz; @@ -46,30 +47,30 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } -static int btf_add_type(struct btf *btf, struct btf_type *t) +static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) { - if (btf->types_size - btf->nr_types < 2) { - struct btf_type **new_types; + /* nr_types is 1-based, so N types means we need N+1-sized array */ + if (btf->nr_types + 2 > btf->type_offs_cap) { + __u32 *new_offs; __u32 expand_by, new_size; - if (btf->types_size == BTF_MAX_NR_TYPES) + if (btf->type_offs_cap == BTF_MAX_NR_TYPES) return -E2BIG; - expand_by = max(btf->types_size >> 2, 16U); - new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by); + expand_by = max(btf->type_offs_cap / 4, 16U); + new_size = min(BTF_MAX_NR_TYPES, btf->type_offs_cap + expand_by); - new_types = libbpf_reallocarray(btf->types, new_size, sizeof(*new_types)); - if (!new_types) + new_offs = libbpf_reallocarray(btf->type_offs, new_size, sizeof(*new_offs)); + if (!new_offs) return -ENOMEM; - if (btf->nr_types == 0) - new_types[0] = &btf_void; + new_offs[0] = UINT_MAX; /* VOID is specially handled */ - btf->types = new_types; - btf->types_size = new_size; + btf->type_offs = new_offs; + btf->type_offs_cap = new_size; } - btf->types[++(btf->nr_types)] = t; + btf->type_offs[btf->nr_types + 1] = type_off; return 0; } @@ -147,7 +148,7 @@ static int btf_parse_str_sec(struct btf *btf) return 0; } -static int btf_type_size(struct btf_type *t) +static int btf_type_size(const struct btf_type *t) { int base_size = sizeof(struct btf_type); __u16 vlen = btf_vlen(t); @@ -185,22 +186,25 @@ static int btf_type_size(struct btf_type *t) static int btf_parse_type_sec(struct btf *btf) { struct btf_header *hdr = btf->hdr; - void *nohdr_data = btf->nohdr_data; - void *next_type = nohdr_data + hdr->type_off; - void *end_type = nohdr_data + hdr->str_off; + void *next_type = btf->nohdr_data + hdr->type_off; + void *end_type = next_type + hdr->type_len; + + btf->types_data = next_type; while (next_type < end_type) { - struct btf_type *t = next_type; int type_size; int err; - type_size = btf_type_size(t); + err = btf_add_type_idx_entry(btf, next_type - btf->types_data); + if (err) + return err; + + type_size = btf_type_size(next_type); if (type_size < 0) return type_size; + next_type += type_size; - err = btf_add_type(btf, t); - if (err) - return err; + btf->nr_types++; } return 0; @@ -211,12 +215,20 @@ __u32 btf__get_nr_types(const struct btf *btf) return btf->nr_types; } +/* internal helper returning non-const pointer to a type */ +static struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id) +{ + if (type_id == 0) + return &btf_void; + + return btf->types_data + btf->type_offs[type_id]; +} + const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) { if (type_id > btf->nr_types) return NULL; - - return btf->types[type_id]; + return btf_type_by_id((struct btf *)btf, type_id); } static int determine_ptr_size(const struct btf *btf) @@ -414,7 +426,7 @@ __s32 btf__find_by_name(const struct btf *btf, const char *type_name) return 0; for (i = 1; i <= btf->nr_types; i++) { - const struct btf_type *t = btf->types[i]; + const struct btf_type *t = btf__type_by_id(btf, i); const char *name = btf__name_by_offset(btf, t->name_off); if (name && !strcmp(type_name, name)) @@ -433,7 +445,7 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, return 0; for (i = 1; i <= btf->nr_types; i++) { - const struct btf_type *t = btf->types[i]; + const struct btf_type *t = btf__type_by_id(btf, i); const char *name; if (btf_kind(t) != kind) @@ -455,7 +467,7 @@ void btf__free(struct btf *btf) close(btf->fd); free(btf->data); - free(btf->types); + free(btf->type_offs); free(btf); } @@ -789,7 +801,7 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf) __u32 i; for (i = 1; i <= btf->nr_types; i++) { - struct btf_type *t = btf->types[i]; + struct btf_type *t = btf_type_by_id(btf, i); /* Loader needs to fix up some of the things compiler * couldn't get its hands on while emitting BTF. This @@ -1655,7 +1667,7 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, /* special BTF "void" type is made canonical immediately */ d->map[0] = 0; for (i = 1; i <= btf->nr_types; i++) { - struct btf_type *t = d->btf->types[i]; + struct btf_type *t = btf_type_by_id(d->btf, i); /* VAR and DATASEC are never deduped and are self-canonical */ if (btf_is_var(t) || btf_is_datasec(t)) @@ -1694,7 +1706,7 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx) struct btf_type *t; for (i = 1; i <= d->btf->nr_types; i++) { - t = d->btf->types[i]; + t = btf_type_by_id(d->btf, i); r = fn(&t->name_off, ctx); if (r) return r; @@ -2229,7 +2241,7 @@ static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) */ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) { - struct btf_type *t = d->btf->types[type_id]; + struct btf_type *t = btf_type_by_id(d->btf, type_id); struct hashmap_entry *hash_entry; struct btf_type *cand; /* if we don't find equivalent type, then we are canonical */ @@ -2256,7 +2268,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_int(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_int(t, cand)) { new_id = cand_id; break; @@ -2268,7 +2280,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_enum(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_enum(t, cand)) { new_id = cand_id; break; @@ -2291,7 +2303,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_common(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_common(t, cand)) { new_id = cand_id; break; @@ -2350,13 +2362,13 @@ static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id) { __u32 orig_type_id = type_id; - if (!btf_is_fwd(d->btf->types[type_id])) + if (!btf_is_fwd(btf__type_by_id(d->btf, type_id))) return type_id; while (is_type_mapped(d, type_id) && d->map[type_id] != type_id) type_id = d->map[type_id]; - if (!btf_is_fwd(d->btf->types[type_id])) + if (!btf_is_fwd(btf__type_by_id(d->btf, type_id))) return type_id; return orig_type_id; @@ -2484,8 +2496,8 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, if (btf_dedup_hypot_map_add(d, canon_id, cand_id)) return -ENOMEM; - cand_type = d->btf->types[cand_id]; - canon_type = d->btf->types[canon_id]; + cand_type = btf_type_by_id(d->btf, cand_id); + canon_type = btf_type_by_id(d->btf, canon_id); cand_kind = btf_kind(cand_type); canon_kind = btf_kind(canon_type); @@ -2636,8 +2648,8 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) targ_type_id = d->hypot_map[cand_type_id]; t_id = resolve_type_id(d, targ_type_id); c_id = resolve_type_id(d, cand_type_id); - t_kind = btf_kind(d->btf->types[t_id]); - c_kind = btf_kind(d->btf->types[c_id]); + t_kind = btf_kind(btf__type_by_id(d->btf, t_id)); + c_kind = btf_kind(btf__type_by_id(d->btf, c_id)); /* * Resolve FWD into STRUCT/UNION. * It's ok to resolve FWD into STRUCT/UNION that's not yet @@ -2705,7 +2717,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) if (d->map[type_id] <= BTF_MAX_NR_TYPES) return 0; - t = d->btf->types[type_id]; + t = btf_type_by_id(d->btf, type_id); kind = btf_kind(t); if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION) @@ -2726,7 +2738,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because * FWD and compatible STRUCT/UNION are considered equivalent. */ - cand_type = d->btf->types[cand_id]; + cand_type = btf_type_by_id(d->btf, cand_id); if (!btf_shallow_equal_struct(t, cand_type)) continue; @@ -2798,7 +2810,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) if (d->map[type_id] <= BTF_MAX_NR_TYPES) return resolve_type_id(d, type_id); - t = d->btf->types[type_id]; + t = btf_type_by_id(d->btf, type_id); d->map[type_id] = BTF_IN_PROGRESS_ID; switch (btf_kind(t)) { @@ -2816,7 +2828,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_common(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_common(t, cand)) { new_id = cand_id; break; @@ -2840,7 +2852,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_array(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_array(t, cand)) { new_id = cand_id; break; @@ -2872,7 +2884,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) h = btf_hash_fnproto(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; - cand = d->btf->types[cand_id]; + cand = btf_type_by_id(d->btf, cand_id); if (btf_equal_fnproto(t, cand)) { new_id = cand_id; break; @@ -2920,9 +2932,9 @@ static int btf_dedup_ref_types(struct btf_dedup *d) */ static int btf_dedup_compact_types(struct btf_dedup *d) { - struct btf_type **new_types; + __u32 *new_offs; __u32 next_type_id = 1; - char *types_start, *p; + void *p; int i, len; /* we are going to reuse hypot_map to store compaction remapping */ @@ -2930,41 +2942,40 @@ static int btf_dedup_compact_types(struct btf_dedup *d) for (i = 1; i <= d->btf->nr_types; i++) d->hypot_map[i] = BTF_UNPROCESSED_ID; - types_start = d->btf->nohdr_data + d->btf->hdr->type_off; - p = types_start; + p = d->btf->types_data; for (i = 1; i <= d->btf->nr_types; i++) { if (d->map[i] != i) continue; - len = btf_type_size(d->btf->types[i]); + len = btf_type_size(btf__type_by_id(d->btf, i)); if (len < 0) return len; - memmove(p, d->btf->types[i], len); + memmove(p, btf__type_by_id(d->btf, i), len); d->hypot_map[i] = next_type_id; - d->btf->types[next_type_id] = (struct btf_type *)p; + d->btf->type_offs[next_type_id] = p - d->btf->types_data; p += len; next_type_id++; } /* shrink struct btf's internal types index and update btf_header */ d->btf->nr_types = next_type_id - 1; - d->btf->types_size = d->btf->nr_types; - d->btf->hdr->type_len = p - types_start; - new_types = libbpf_reallocarray(d->btf->types, (1 + d->btf->nr_types), - sizeof(struct btf_type *)); - if (!new_types) + d->btf->type_offs_cap = d->btf->nr_types + 1; + d->btf->hdr->type_len = p - d->btf->types_data; + new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap, + sizeof(*new_offs)); + if (!new_offs) return -ENOMEM; - d->btf->types = new_types; + d->btf->type_offs = new_offs; /* make sure string section follows type information without gaps */ - d->btf->hdr->str_off = p - (char *)d->btf->nohdr_data; + d->btf->hdr->str_off = p - d->btf->nohdr_data; memmove(p, d->btf->strings, d->btf->hdr->str_len); d->btf->strings = p; p += d->btf->hdr->str_len; - d->btf->data_size = p - (char *)d->btf->data; + d->btf->data_size = p - d->btf->data; return 0; } @@ -2997,7 +3008,7 @@ static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id) */ static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id) { - struct btf_type *t = d->btf->types[type_id]; + struct btf_type *t = btf_type_by_id(d->btf, type_id); int i, r; switch (btf_kind(t)) { -- cgit v1.2.3 From b86042478fa083d87f1b67047e788d70b8c81eef Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 25 Sep 2020 18:13:50 -0700 Subject: libbpf: Remove assumption of single contiguous memory for BTF data Refactor internals of struct btf to remove assumptions that BTF header, type data, and string data are layed out contiguously in a memory in a single memory allocation. Now we have three separate pointers pointing to the start of each respective are: header, types, strings. In the next patches, these pointers will be re-assigned to point to independently allocated memory areas, if BTF needs to be modified. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200926011357.2366158-3-andriin@fb.com --- tools/lib/bpf/bpf.c | 2 +- tools/lib/bpf/bpf.h | 2 +- tools/lib/bpf/btf.c | 99 +++++++++++++++++++++++++++++++---------------------- 3 files changed, 60 insertions(+), 43 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index c5a4d8444bf6..70575a37aa14 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -846,7 +846,7 @@ int bpf_raw_tracepoint_open(const char *name, int prog_fd) return sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr)); } -int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size, +int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size, bool do_log) { union bpf_attr attr = {}; diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 4f3568e55527..16806810a53c 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -234,7 +234,7 @@ LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags, __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt); LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd); -LIBBPF_API int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, +LIBBPF_API int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size, bool do_log); LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len, __u32 *prog_id, __u32 *fd_type, diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7c9957893ef2..d180a677a3fb 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -27,18 +27,37 @@ static struct btf_type btf_void; struct btf { - union { - struct btf_header *hdr; - void *data; - }; + void *raw_data; + __u32 raw_size; + + /* + * When BTF is loaded from ELF or raw memory it is stored + * in contiguous memory block, pointed to by raw_data pointer, and + * hdr, types_data, and strs_data point inside that memory region to + * respective parts of BTF representation: + * + * +--------------------------------+ + * | Header | Types | Strings | + * +--------------------------------+ + * ^ ^ ^ + * | | | + * hdr | | + * types_data-+ | + * strs_data------------+ + */ + struct btf_header *hdr; + void *types_data; + void *strs_data; + + /* type ID to `struct btf_type *` lookup index */ __u32 *type_offs; __u32 type_offs_cap; - const char *strings; - void *nohdr_data; - void *types_data; __u32 nr_types; - __u32 data_size; + + /* BTF object FD, if loaded into kernel */ int fd; + + /* Pointer size (in bytes) for a target architecture of this BTF */ int ptr_sz; }; @@ -80,7 +99,7 @@ static int btf_parse_hdr(struct btf *btf) const struct btf_header *hdr = btf->hdr; __u32 meta_left; - if (btf->data_size < sizeof(struct btf_header)) { + if (btf->raw_size < sizeof(struct btf_header)) { pr_debug("BTF header not found\n"); return -EINVAL; } @@ -100,7 +119,7 @@ static int btf_parse_hdr(struct btf *btf) return -ENOTSUP; } - meta_left = btf->data_size - sizeof(*hdr); + meta_left = btf->raw_size - sizeof(*hdr); if (!meta_left) { pr_debug("BTF has no data\n"); return -EINVAL; @@ -126,15 +145,13 @@ static int btf_parse_hdr(struct btf *btf) return -EINVAL; } - btf->nohdr_data = btf->hdr + 1; - return 0; } static int btf_parse_str_sec(struct btf *btf) { const struct btf_header *hdr = btf->hdr; - const char *start = btf->nohdr_data + hdr->str_off; + const char *start = btf->strs_data; const char *end = start + btf->hdr->str_len; if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || @@ -143,8 +160,6 @@ static int btf_parse_str_sec(struct btf *btf) return -EINVAL; } - btf->strings = start; - return 0; } @@ -186,11 +201,9 @@ static int btf_type_size(const struct btf_type *t) static int btf_parse_type_sec(struct btf *btf) { struct btf_header *hdr = btf->hdr; - void *next_type = btf->nohdr_data + hdr->type_off; + void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; - btf->types_data = next_type; - while (next_type < end_type) { int type_size; int err; @@ -466,7 +479,7 @@ void btf__free(struct btf *btf) if (btf->fd >= 0) close(btf->fd); - free(btf->data); + free(btf->raw_data); free(btf->type_offs); free(btf); } @@ -482,24 +495,24 @@ struct btf *btf__new(const void *data, __u32 size) btf->fd = -1; - btf->data = malloc(size); - if (!btf->data) { + btf->raw_data = malloc(size); + if (!btf->raw_data) { err = -ENOMEM; goto done; } + memcpy(btf->raw_data, data, size); + btf->raw_size = size; - memcpy(btf->data, data, size); - btf->data_size = size; - + btf->hdr = btf->raw_data; err = btf_parse_hdr(btf); if (err) goto done; - err = btf_parse_str_sec(btf); - if (err) - goto done; + btf->strs_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->str_off; + btf->types_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->type_off; - err = btf_parse_type_sec(btf); + err = btf_parse_str_sec(btf); + err = err ?: btf_parse_type_sec(btf); done: if (err) { @@ -820,8 +833,9 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf) int btf__load(struct btf *btf) { - __u32 log_buf_size = 0; + __u32 log_buf_size = 0, raw_size; char *log_buf = NULL; + const void *raw_data; int err = 0; if (btf->fd >= 0) @@ -836,8 +850,13 @@ retry_load: *log_buf = 0; } - btf->fd = bpf_load_btf(btf->data, btf->data_size, - log_buf, log_buf_size, false); + raw_data = btf__get_raw_data(btf, &raw_size); + if (!raw_data) { + err = -ENOMEM; + goto done; + } + + btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false); if (btf->fd < 0) { if (!log_buf || errno == ENOSPC) { log_buf_size = max((__u32)BPF_LOG_BUF_SIZE, @@ -870,14 +889,14 @@ void btf__set_fd(struct btf *btf, int fd) const void *btf__get_raw_data(const struct btf *btf, __u32 *size) { - *size = btf->data_size; - return btf->data; + *size = btf->raw_size; + return btf->raw_data; } const char *btf__name_by_offset(const struct btf *btf, __u32 offset) { if (offset < btf->hdr->str_len) - return &btf->strings[offset]; + return btf->strs_data + offset; else return NULL; } @@ -1860,8 +1879,7 @@ static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) */ static int btf_dedup_strings(struct btf_dedup *d) { - const struct btf_header *hdr = d->btf->hdr; - char *start = (char *)d->btf->nohdr_data + hdr->str_off; + char *start = d->btf->strs_data; char *end = start + d->btf->hdr->str_len; char *p = start, *tmp_strs = NULL; struct btf_str_ptrs strs = { @@ -2970,12 +2988,11 @@ static int btf_dedup_compact_types(struct btf_dedup *d) d->btf->type_offs = new_offs; /* make sure string section follows type information without gaps */ - d->btf->hdr->str_off = p - d->btf->nohdr_data; - memmove(p, d->btf->strings, d->btf->hdr->str_len); - d->btf->strings = p; - p += d->btf->hdr->str_len; + d->btf->hdr->str_off = p - d->btf->types_data; + memmove(p, d->btf->strs_data, d->btf->hdr->str_len); + d->btf->strs_data = p; - d->btf->data_size = p - d->btf->data; + d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len; return 0; } -- cgit v1.2.3 From 192f5a1fe6894dca58d14dc883e6c7030e7267f7 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 25 Sep 2020 18:13:51 -0700 Subject: libbpf: Generalize common logic for managing dynamically-sized arrays Managing dynamically-sized array is a common, but not trivial functionality, which significant amount of logic and code to implement properly. So instead of re-implementing it all the time, extract it into a helper function ans reuse. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200926011357.2366158-4-andriin@fb.com --- tools/lib/bpf/btf.c | 77 ++++++++++++++++++++++++++++++----------- tools/lib/bpf/libbpf_internal.h | 3 ++ 2 files changed, 59 insertions(+), 21 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index d180a677a3fb..f5255e2bd222 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -51,7 +51,7 @@ struct btf { /* type ID to `struct btf_type *` lookup index */ __u32 *type_offs; - __u32 type_offs_cap; + size_t type_offs_cap; __u32 nr_types; /* BTF object FD, if loaded into kernel */ @@ -66,31 +66,60 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } -static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) +/* Ensure given dynamically allocated memory region pointed to by *data* with + * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough + * memory to accomodate *add_cnt* new elements, assuming *cur_cnt* elements + * are already used. At most *max_cnt* elements can be ever allocated. + * If necessary, memory is reallocated and all existing data is copied over, + * new pointer to the memory region is stored at *data, new memory region + * capacity (in number of elements) is stored in *cap. + * On success, memory pointer to the beginning of unused memory is returned. + * On error, NULL is returned. + */ +void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt) { - /* nr_types is 1-based, so N types means we need N+1-sized array */ - if (btf->nr_types + 2 > btf->type_offs_cap) { - __u32 *new_offs; - __u32 expand_by, new_size; + size_t new_cnt; + void *new_data; - if (btf->type_offs_cap == BTF_MAX_NR_TYPES) - return -E2BIG; + if (cur_cnt + add_cnt <= *cap_cnt) + return *data + cur_cnt * elem_sz; - expand_by = max(btf->type_offs_cap / 4, 16U); - new_size = min(BTF_MAX_NR_TYPES, btf->type_offs_cap + expand_by); + /* requested more than the set limit */ + if (cur_cnt + add_cnt > max_cnt) + return NULL; - new_offs = libbpf_reallocarray(btf->type_offs, new_size, sizeof(*new_offs)); - if (!new_offs) - return -ENOMEM; + new_cnt = *cap_cnt; + new_cnt += new_cnt / 4; /* expand by 25% */ + if (new_cnt < 16) /* but at least 16 elements */ + new_cnt = 16; + if (new_cnt > max_cnt) /* but not exceeding a set limit */ + new_cnt = max_cnt; + if (new_cnt < cur_cnt + add_cnt) /* also ensure we have enough memory */ + new_cnt = cur_cnt + add_cnt; + + new_data = libbpf_reallocarray(*data, new_cnt, elem_sz); + if (!new_data) + return NULL; - new_offs[0] = UINT_MAX; /* VOID is specially handled */ + /* zero out newly allocated portion of memory */ + memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz); - btf->type_offs = new_offs; - btf->type_offs_cap = new_size; - } + *data = new_data; + *cap_cnt = new_cnt; + return new_data + cur_cnt * elem_sz; +} - btf->type_offs[btf->nr_types + 1] = type_off; +static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) +{ + __u32 *p; + + p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32), + btf->nr_types + 1, BTF_MAX_NR_TYPES, 1); + if (!p) + return -ENOMEM; + *p = type_off; return 0; } @@ -203,11 +232,17 @@ static int btf_parse_type_sec(struct btf *btf) struct btf_header *hdr = btf->hdr; void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; + int err, type_size; - while (next_type < end_type) { - int type_size; - int err; + /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), + * so ensure we can never properly use its offset from index by + * setting it to a large value + */ + err = btf_add_type_idx_entry(btf, UINT_MAX); + if (err) + return err; + while (next_type < end_type) { err = btf_add_type_idx_entry(btf, next_type - btf->types_data); if (err) return err; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index d3f7a6a6bc98..eed5b624a784 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -105,6 +105,9 @@ static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) return realloc(ptr, total); } +void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt); + static inline bool libbpf_validate_opts(const char *opts, size_t opts_sz, size_t user_sz, const char *type_name) -- cgit v1.2.3 From 7d9c71e10baa3496d95226aa3bba668f7533ec70 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 25 Sep 2020 18:13:52 -0700 Subject: libbpf: Extract generic string hashing function for reuse Calculating a hash of zero-terminated string is a common need when using hashmap, so extract it for reuse. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200926011357.2366158-5-andriin@fb.com --- tools/lib/bpf/btf_dump.c | 9 +-------- tools/lib/bpf/hashmap.h | 12 ++++++++++++ 2 files changed, 13 insertions(+), 8 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 6c079b3c8679..91310e528a3a 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -90,14 +90,7 @@ struct btf_dump { static size_t str_hash_fn(const void *key, void *ctx) { - const char *s = key; - size_t h = 0; - - while (*s) { - h = h * 31 + *s; - s++; - } - return h; + return str_hash(key); } static bool str_equal_fn(const void *a, const void *b, void *ctx) diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h index e0af36b0e5d8..d9b385fe808c 100644 --- a/tools/lib/bpf/hashmap.h +++ b/tools/lib/bpf/hashmap.h @@ -25,6 +25,18 @@ static inline size_t hash_bits(size_t h, int bits) #endif } +/* generic C-string hashing function */ +static inline size_t str_hash(const char *s) +{ + size_t h = 0; + + while (*s) { + h = h * 31 + *s; + s++; + } + return h; +} + typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); -- cgit v1.2.3 From 919d2b1dbb074d438027135ba644411931179a59 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 25 Sep 2020 18:13:53 -0700 Subject: libbpf: Allow modification of BTF and add btf__add_str API Allow internal BTF representation to switch from default read-only mode, in which raw BTF data is a single non-modifiable block of memory with BTF header, types, and strings layed out sequentially and contiguously in memory, into a writable representation with types and strings data split out into separate memory regions, that can be dynamically expanded. Such writable internal representation is transparent to users of libbpf APIs, but allows to append new types and strings at the end of BTF, which is a typical use case when generating BTF programmatically. All the basic guarantees of BTF types and strings layout is preserved, i.e., user can get `struct btf_type *` pointer and read it directly. Such btf_type pointers might be invalidated if BTF is modified, so some care is required in such mixed read/write scenarios. Switch from read-only to writable configuration happens automatically the first time when user attempts to modify BTF by either adding a new type or new string. It is still possible to get raw BTF data, which is a single piece of memory that can be persisted in ELF section or into a file as raw BTF. Such raw data memory is also still owned by BTF and will be freed either when BTF object is freed or if another modification to BTF happens, as any modification invalidates BTF raw representation. This patch adds the first two BTF manipulation APIs: btf__add_str(), which allows to add arbitrary strings to BTF string section, and btf__find_str() which allows to find existing string offset, but not add it if it's missing. All the added strings are automatically deduplicated. This is achieved by maintaining an additional string lookup index for all unique strings. Such index is built when BTF is switched to modifiable mode. If at that time BTF strings section contained duplicate strings, they are not de-duplicated. This is done specifically to not modify the existing content of BTF (types, their string offsets, etc), which can cause confusion and is especially important property if there is struct btf_ext associated with struct btf. By following this "imperfect deduplication" process, btf_ext is kept consitent and correct. If deduplication of strings is necessary, it can be forced by doing BTF deduplication, at which point all the strings will be eagerly deduplicated and all string offsets both in struct btf and struct btf_ext will be updated. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200926011357.2366158-6-andriin@fb.com --- tools/lib/bpf/btf.c | 260 +++++++++++++++++++++++++++++++++++++++++++++-- tools/lib/bpf/btf.h | 4 + tools/lib/bpf/libbpf.map | 2 + 3 files changed, 258 insertions(+), 8 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index f5255e2bd222..040f3b8ee39f 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -44,16 +44,46 @@ struct btf { * hdr | | * types_data-+ | * strs_data------------+ + * + * If BTF data is later modified, e.g., due to types added or + * removed, BTF deduplication performed, etc, this contiguous + * representation is broken up into three independently allocated + * memory regions to be able to modify them independently. + * raw_data is nulled out at that point, but can be later allocated + * and cached again if user calls btf__get_raw_data(), at which point + * raw_data will contain a contiguous copy of header, types, and + * strings: + * + * +----------+ +---------+ +-----------+ + * | Header | | Types | | Strings | + * +----------+ +---------+ +-----------+ + * ^ ^ ^ + * | | | + * hdr | | + * types_data----+ | + * strs_data------------------+ + * + * +----------+---------+-----------+ + * | Header | Types | Strings | + * raw_data----->+----------+---------+-----------+ */ struct btf_header *hdr; + void *types_data; - void *strs_data; + size_t types_data_cap; /* used size stored in hdr->type_len */ /* type ID to `struct btf_type *` lookup index */ __u32 *type_offs; size_t type_offs_cap; __u32 nr_types; + void *strs_data; + size_t strs_data_cap; /* used size stored in hdr->str_len */ + + /* lookup index for each unique string in strings section */ + struct hashmap *strs_hash; + /* whether strings are already deduplicated */ + bool strs_deduped; /* BTF object FD, if loaded into kernel */ int fd; @@ -506,6 +536,11 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, return -ENOENT; } +static bool btf_is_modifiable(const struct btf *btf) +{ + return (void *)btf->hdr != btf->raw_data; +} + void btf__free(struct btf *btf) { if (IS_ERR_OR_NULL(btf)) @@ -514,6 +549,17 @@ void btf__free(struct btf *btf) if (btf->fd >= 0) close(btf->fd); + if (btf_is_modifiable(btf)) { + /* if BTF was modified after loading, it will have a split + * in-memory representation for header, types, and strings + * sections, so we need to free all of them individually. It + * might still have a cached contiguous raw data present, + * which will be unconditionally freed below. + */ + free(btf->hdr); + free(btf->types_data); + free(btf->strs_data); + } free(btf->raw_data); free(btf->type_offs); free(btf); @@ -922,8 +968,29 @@ void btf__set_fd(struct btf *btf, int fd) btf->fd = fd; } -const void *btf__get_raw_data(const struct btf *btf, __u32 *size) +const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) { + struct btf *btf = (struct btf *)btf_ro; + + if (!btf->raw_data) { + struct btf_header *hdr = btf->hdr; + void *data; + + btf->raw_size = hdr->hdr_len + hdr->type_len + hdr->str_len; + btf->raw_data = calloc(1, btf->raw_size); + if (!btf->raw_data) + return NULL; + data = btf->raw_data; + + memcpy(data, hdr, hdr->hdr_len); + data += hdr->hdr_len; + + memcpy(data, btf->types_data, hdr->type_len); + data += hdr->type_len; + + memcpy(data, btf->strs_data, hdr->str_len); + data += hdr->str_len; + } *size = btf->raw_size; return btf->raw_data; } @@ -1071,6 +1138,181 @@ int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, return 0; } +static size_t strs_hash_fn(const void *key, void *ctx) +{ + struct btf *btf = ctx; + const char *str = btf->strs_data + (long)key; + + return str_hash(str); +} + +static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx) +{ + struct btf *btf = ctx; + const char *str1 = btf->strs_data + (long)key1; + const char *str2 = btf->strs_data + (long)key2; + + return strcmp(str1, str2) == 0; +} + +/* Ensure BTF is ready to be modified (by splitting into a three memory + * regions for header, types, and strings). Also invalidate cached + * raw_data, if any. + */ +static int btf_ensure_modifiable(struct btf *btf) +{ + void *hdr, *types, *strs, *strs_end, *s; + struct hashmap *hash = NULL; + long off; + int err; + + if (btf_is_modifiable(btf)) { + /* any BTF modification invalidates raw_data */ + if (btf->raw_data) { + free(btf->raw_data); + btf->raw_data = NULL; + } + return 0; + } + + /* split raw data into three memory regions */ + hdr = malloc(btf->hdr->hdr_len); + types = malloc(btf->hdr->type_len); + strs = malloc(btf->hdr->str_len); + if (!hdr || !types || !strs) + goto err_out; + + memcpy(hdr, btf->hdr, btf->hdr->hdr_len); + memcpy(types, btf->types_data, btf->hdr->type_len); + memcpy(strs, btf->strs_data, btf->hdr->str_len); + + /* build lookup index for all strings */ + hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, btf); + if (IS_ERR(hash)) { + err = PTR_ERR(hash); + hash = NULL; + goto err_out; + } + + strs_end = strs + btf->hdr->str_len; + for (off = 0, s = strs; s < strs_end; off += strlen(s) + 1, s = strs + off) { + /* hashmap__add() returns EEXIST if string with the same + * content already is in the hash map + */ + err = hashmap__add(hash, (void *)off, (void *)off); + if (err == -EEXIST) + continue; /* duplicate */ + if (err) + goto err_out; + } + + /* only when everything was successful, update internal state */ + btf->hdr = hdr; + btf->types_data = types; + btf->types_data_cap = btf->hdr->type_len; + btf->strs_data = strs; + btf->strs_data_cap = btf->hdr->str_len; + btf->strs_hash = hash; + /* if BTF was created from scratch, all strings are guaranteed to be + * unique and deduplicated + */ + btf->strs_deduped = btf->hdr->str_len <= 1; + + /* invalidate raw_data representation */ + free(btf->raw_data); + btf->raw_data = NULL; + + return 0; + +err_out: + hashmap__free(hash); + free(hdr); + free(types); + free(strs); + return -ENOMEM; +} + +static void *btf_add_str_mem(struct btf *btf, size_t add_sz) +{ + return btf_add_mem(&btf->strs_data, &btf->strs_data_cap, 1, + btf->hdr->str_len, BTF_MAX_STR_OFFSET, add_sz); +} + +/* Find an offset in BTF string section that corresponds to a given string *s*. + * Returns: + * - >0 offset into string section, if string is found; + * - -ENOENT, if string is not in the string section; + * - <0, on any other error. + */ +int btf__find_str(struct btf *btf, const char *s) +{ + long old_off, new_off, len; + void *p; + + /* BTF needs to be in a modifiable state to build string lookup index */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + /* see btf__add_str() for why we do this */ + len = strlen(s) + 1; + p = btf_add_str_mem(btf, len); + if (!p) + return -ENOMEM; + + new_off = btf->hdr->str_len; + memcpy(p, s, len); + + if (hashmap__find(btf->strs_hash, (void *)new_off, (void **)&old_off)) + return old_off; + + return -ENOENT; +} + +/* Add a string s to the BTF string section. + * Returns: + * - > 0 offset into string section, on success; + * - < 0, on error. + */ +int btf__add_str(struct btf *btf, const char *s) +{ + long old_off, new_off, len; + void *p; + int err; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + /* Hashmap keys are always offsets within btf->strs_data, so to even + * look up some string from the "outside", we need to first append it + * at the end, so that it can be addressed with an offset. Luckily, + * until btf->hdr->str_len is incremented, that string is just a piece + * of garbage for the rest of BTF code, so no harm, no foul. On the + * other hand, if the string is unique, it's already appended and + * ready to be used, only a simple btf->hdr->str_len increment away. + */ + len = strlen(s) + 1; + p = btf_add_str_mem(btf, len); + if (!p) + return -ENOMEM; + + new_off = btf->hdr->str_len; + memcpy(p, s, len); + + /* Now attempt to add the string, but only if the string with the same + * contents doesn't exist already (HASHMAP_ADD strategy). If such + * string exists, we'll get its offset in old_off (that's old_key). + */ + err = hashmap__insert(btf->strs_hash, (void *)new_off, (void *)new_off, + HASHMAP_ADD, (const void **)&old_off, NULL); + if (err == -EEXIST) + return old_off; /* duplicated string, return existing offset */ + if (err) + return err; + + btf->hdr->str_len += len; /* new unique string, adjust data length */ + return new_off; +} + struct btf_ext_sec_setup_param { __u32 off; __u32 len; @@ -1537,6 +1779,9 @@ int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, return -EINVAL; } + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + err = btf_dedup_strings(d); if (err < 0) { pr_debug("btf_dedup_strings failed:%d\n", err); @@ -1926,6 +2171,9 @@ static int btf_dedup_strings(struct btf_dedup *d) int i, j, err = 0, grp_idx; bool grp_used; + if (d->btf->strs_deduped) + return 0; + /* build index of all strings */ while (p < end) { if (strs.cnt + 1 > strs.cap) { @@ -2018,6 +2266,7 @@ static int btf_dedup_strings(struct btf_dedup *d) goto done; d->btf->hdr->str_len = end - start; + d->btf->strs_deduped = true; done: free(tmp_strs); @@ -3021,12 +3270,7 @@ static int btf_dedup_compact_types(struct btf_dedup *d) if (!new_offs) return -ENOMEM; d->btf->type_offs = new_offs; - - /* make sure string section follows type information without gaps */ - d->btf->hdr->str_off = p - d->btf->types_data; - memmove(p, d->btf->strs_data, d->btf->hdr->str_len); - d->btf->strs_data = p; - + d->btf->hdr->str_off = d->btf->hdr->type_len; d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len; return 0; } diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 2a55320d87d0..d88b6447c222 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -5,6 +5,7 @@ #define __LIBBPF_BTF_H #include +#include #include #include @@ -72,6 +73,9 @@ LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); LIBBPF_API struct btf *libbpf_find_kernel_btf(void); +LIBBPF_API int btf__find_str(struct btf *btf, const char *s); +LIBBPF_API int btf__add_str(struct btf *btf, const char *s); + struct btf_dedup_opts { unsigned int dedup_table_size; bool dont_resolve_fwds; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 0623e7a99b1e..f1518c51d2e5 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -305,6 +305,8 @@ LIBBPF_0.2.0 { bpf_prog_bind_map; bpf_prog_test_run_opts; bpf_program__section_name; + btf__add_str; + btf__find_str; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; perf_buffer__epoll_fd; -- cgit v1.2.3 From a871b04310248024e022e104eba3ec81d144cc64 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 25 Sep 2020 18:13:54 -0700 Subject: libbpf: Add btf__new_empty() to create an empty BTF object Add an ability to create an empty BTF object from scratch. This is going to be used by pahole for BTF encoding. And also by selftest for convenient creation of BTF objects. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200926011357.2366158-7-andriin@fb.com --- tools/lib/bpf/btf.c | 30 ++++++++++++++++++++++++++++++ tools/lib/bpf/btf.h | 1 + tools/lib/bpf/libbpf.map | 1 + 3 files changed, 32 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 040f3b8ee39f..54861a5ba9d9 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -565,6 +565,36 @@ void btf__free(struct btf *btf) free(btf); } +struct btf *btf__new_empty(void) +{ + struct btf *btf; + + btf = calloc(1, sizeof(*btf)); + if (!btf) + return ERR_PTR(-ENOMEM); + btf->fd = -1; + btf->ptr_sz = sizeof(void *); + + /* +1 for empty string at offset 0 */ + btf->raw_size = sizeof(struct btf_header) + 1; + btf->raw_data = calloc(1, btf->raw_size); + if (!btf->raw_data) { + free(btf); + return ERR_PTR(-ENOMEM); + } + + btf->hdr = btf->raw_data; + btf->hdr->hdr_len = sizeof(struct btf_header); + btf->hdr->magic = BTF_MAGIC; + btf->hdr->version = BTF_VERSION; + + btf->types_data = btf->raw_data + btf->hdr->hdr_len; + btf->strs_data = btf->raw_data + btf->hdr->hdr_len; + btf->hdr->str_len = 1; /* empty string at offset 0 */ + + return btf; +} + struct btf *btf__new(const void *data, __u32 size) { struct btf *btf; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index d88b6447c222..b387d0b61f1c 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -27,6 +27,7 @@ struct bpf_object; LIBBPF_API void btf__free(struct btf *btf); LIBBPF_API struct btf *btf__new(const void *data, __u32 size); +LIBBPF_API struct btf *btf__new_empty(void); LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext); LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext); LIBBPF_API struct btf *btf__parse_raw(const char *path); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index f1518c51d2e5..d02d8f51e34f 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -307,6 +307,7 @@ LIBBPF_0.2.0 { bpf_program__section_name; btf__add_str; btf__find_str; + btf__new_empty; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; perf_buffer__epoll_fd; -- cgit v1.2.3 From 4a3b33f8579af182ebcf9c7e9304effce505500e Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 28 Sep 2020 19:05:30 -0700 Subject: libbpf: Add BTF writing APIs Add APIs for appending new BTF types at the end of BTF object. Each BTF kind has either one API of the form btf__add_(). For types that have variable amount of additional items (struct/union, enum, func_proto, datasec), additional API is provided to emit each such item. E.g., for emitting a struct, one would use the following sequence of API calls: btf__add_struct(...); btf__add_field(...); ... btf__add_field(...); Each btf__add_field() will ensure that the last BTF type is of STRUCT or UNION kind and will automatically increment that type's vlen field. All the strings are provided as C strings (const char *), not a string offset. This significantly improves usability of BTF writer APIs. All such strings will be automatically appended to string section or existing string will be re-used, if such string was already added previously. Each API attempts to do all the reasonable validations, like enforcing non-empty names for entities with required names, proper value bounds, various bit offset restrictions, etc. Type ID validation is minimal because it's possible to emit a type that refers to type that will be emitted later, so libbpf has no way to enforce such cases. User must be careful to properly emit all the necessary types and specify type IDs that will be valid in the finally generated BTF. Each of btf__add_() APIs return new type ID on success or negative value on error. APIs like btf__add_field() that emit additional items return zero on success and negative value on error. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200929020533.711288-2-andriin@fb.com --- tools/lib/bpf/btf.c | 781 +++++++++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/btf.h | 38 +++ tools/lib/bpf/libbpf.map | 19 ++ 3 files changed, 838 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 54861a5ba9d9..7533088b2524 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1343,6 +1343,787 @@ int btf__add_str(struct btf *btf, const char *s) return new_off; } +static void *btf_add_type_mem(struct btf *btf, size_t add_sz) +{ + return btf_add_mem(&btf->types_data, &btf->types_data_cap, 1, + btf->hdr->type_len, UINT_MAX, add_sz); +} + +static __u32 btf_type_info(int kind, int vlen, int kflag) +{ + return (kflag << 31) | (kind << 24) | vlen; +} + +static void btf_type_inc_vlen(struct btf_type *t) +{ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); +} + +/* + * Append new BTF_KIND_INT type with: + * - *name* - non-empty, non-NULL type name; + * - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes; + * - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding) +{ + struct btf_type *t; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16) + return -EINVAL; + if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL)) + return -EINVAL; + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(int); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + /* if something goes wrong later, we might end up with an extra string, + * but that shouldn't be a problem, because BTF can't be constructed + * completely anyway and will most probably be just discarded + */ + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_INT, 0, 0); + t->size = byte_sz; + /* set INT info, we don't allow setting legacy bit offset/size */ + *(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8); + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* it's completely legal to append BTF types with type IDs pointing forward to + * types that haven't been appended yet, so we only make sure that id looks + * sane, we can't guarantee that ID will always be valid + */ +static int validate_type_id(int id) +{ + if (id < 0 || id > BTF_MAX_NR_TYPES) + return -EINVAL; + return 0; +} + +/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */ +static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id) +{ + struct btf_type *t; + int sz, name_off = 0, err; + + if (validate_type_id(ref_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->type = ref_type_id; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_PTR type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_ptr(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_ARRAY type with: + * - *index_type_id* - type ID of the type describing array index; + * - *elem_type_id* - type ID of the type describing array element; + * - *nr_elems* - the size of the array; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems) +{ + struct btf_type *t; + struct btf_array *a; + int sz, err; + + if (validate_type_id(index_type_id) || validate_type_id(elem_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(struct btf_array); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0); + t->size = 0; + + a = btf_array(t); + a->type = elem_type_id; + a->index_type = index_type_id; + a->nelems = nr_elems; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* generic STRUCT/UNION append function */ +static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz) +{ + struct btf_type *t; + int sz, err, name_off = 0; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0 and no kflag; this will be adjusted when + * adding each member + */ + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->size = bytes_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_STRUCT type with: + * - *name* - name of the struct, can be NULL or empty for anonymous structs; + * - *byte_sz* - size of the struct, in bytes; + * + * Struct initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_struct() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz); +} + +/* + * Append new BTF_KIND_UNION type with: + * - *name* - name of the union, can be NULL or empty for anonymous union; + * - *byte_sz* - size of the union, in bytes; + * + * Union initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_union() succeeds. All fields + * should have *bit_offset* of 0. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz); +} + +/* + * Append new field for the current STRUCT/UNION type with: + * - *name* - name of the field, can be NULL or empty for anonymous field; + * - *type_id* - type ID for the type describing field type; + * - *bit_offset* - bit offset of the start of the field within struct/union; + * - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_field(struct btf *btf, const char *name, int type_id, + __u32 bit_offset, __u32 bit_size) +{ + struct btf_type *t; + struct btf_member *m; + bool is_bitfield; + int sz, name_off = 0; + + /* last type should be union/struct */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_composite(t)) + return -EINVAL; + + if (validate_type_id(type_id)) + return -EINVAL; + /* best-effort bit field offset/size enforcement */ + is_bitfield = bit_size || (bit_offset % 8 != 0); + if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff)) + return -EINVAL; + + /* only offset 0 is allowed for unions */ + if (btf_is_union(t) && bit_offset) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_member); + m = btf_add_type_mem(btf, sz); + if (!m) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + m->name_off = name_off; + m->type = type_id; + m->offset = bit_offset | (bit_size << 24); + + /* btf_add_type_mem can invalidate t pointer */ + t = btf_type_by_id(btf, btf->nr_types); + /* update parent type's vlen and kflag */ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t)); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_ENUM type with: + * - *name* - name of the enum, can be NULL or empty for anonymous enums; + * - *byte_sz* - size of the enum, in bytes. + * + * Enum initially has no enum values in it (and corresponds to enum forward + * declaration). Enumerator values can be added by btf__add_enum_value() + * immediately after btf__add_enum() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, err, name_off = 0; + + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0; it will be adjusted when adding enum values */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_ENUM, 0, 0); + t->size = byte_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new enum value for the current ENUM type with: + * - *name* - name of the enumerator value, can't be NULL or empty; + * - *value* - integer value corresponding to enum value *name*; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) +{ + struct btf_type *t; + struct btf_enum *v; + int sz, name_off; + + /* last type should be BTF_KIND_ENUM */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_enum(t)) + return -EINVAL; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + if (value < INT_MIN || value > UINT_MAX) + return -E2BIG; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_enum); + v = btf_add_type_mem(btf, sz); + if (!v) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + v->name_off = name_off; + v->val = value; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_FWD type with: + * - *name*, non-empty/non-NULL name; + * - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT, + * BTF_FWD_UNION, or BTF_FWD_ENUM; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind) +{ + if (!name || !name[0]) + return -EINVAL; + + switch (fwd_kind) { + case BTF_FWD_STRUCT: + case BTF_FWD_UNION: { + struct btf_type *t; + int id; + + id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0); + if (id <= 0) + return id; + t = btf_type_by_id(btf, id); + t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION); + return id; + } + case BTF_FWD_ENUM: + /* enum forward in BTF currently is just an enum with no enum + * values; we also assume a standard 4-byte size for it + */ + return btf__add_enum(btf, name, sizeof(int)); + default: + return -EINVAL; + } +} + +/* + * Append new BTF_KING_TYPEDEF type with: + * - *name*, non-empty/non-NULL name; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id) +{ + if (!name || !name[0]) + return -EINVAL; + + return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id); +} + +/* + * Append new BTF_KIND_VOLATILE type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_volatile(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_CONST type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_const(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_RESTRICT type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_restrict(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_FUNC type with: + * - *name*, non-empty/non-NULL name; + * - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id) +{ + int id; + + if (!name || !name[0]) + return -EINVAL; + if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL && + linkage != BTF_FUNC_EXTERN) + return -EINVAL; + + id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id); + if (id > 0) { + struct btf_type *t = btf_type_by_id(btf, id); + + t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0); + } + return id; +} + +/* + * Append new BTF_KIND_FUNC_PROTO with: + * - *ret_type_id* - type ID for return result of a function. + * + * Function prototype initially has no arguments, but they can be added by + * btf__add_func_param() one by one, immediately after + * btf__add_func_proto() succeeded. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func_proto(struct btf *btf, int ret_type_id) +{ + struct btf_type *t; + int sz, err; + + if (validate_type_id(ret_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + /* start out with vlen=0; this will be adjusted when adding enum + * values, if necessary + */ + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0); + t->type = ret_type_id; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new function parameter for current FUNC_PROTO type with: + * - *name* - parameter name, can be NULL or empty; + * - *type_id* - type ID describing the type of the parameter. + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_func_param(struct btf *btf, const char *name, int type_id) +{ + struct btf_type *t; + struct btf_param *p; + int sz, name_off = 0; + + if (validate_type_id(type_id)) + return -EINVAL; + + /* last type should be BTF_KIND_FUNC_PROTO */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_func_proto(t)) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_param); + p = btf_add_type_mem(btf, sz); + if (!p) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + p->name_off = name_off; + p->type = type_id; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_VAR type with: + * - *name* - non-empty/non-NULL name; + * - *linkage* - variable linkage, one of BTF_VAR_STATIC, + * BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN; + * - *type_id* - type ID of the type describing the type of the variable. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) +{ + struct btf_type *t; + struct btf_var *v; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED && + linkage != BTF_VAR_GLOBAL_EXTERN) + return -EINVAL; + if (validate_type_id(type_id)) + return -EINVAL; + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(struct btf_var); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_VAR, 0, 0); + t->type = type_id; + + v = btf_var(t); + v->linkage = linkage; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_DATASEC type with: + * - *name* - non-empty/non-NULL name; + * - *byte_sz* - data section size, in bytes. + * + * Data section is initially empty. Variables info can be added with + * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + /* start with vlen=0, which will be update as var_secinfos are added */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0); + t->size = byte_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new data section variable information entry for current DATASEC type: + * - *var_type_id* - type ID, describing type of the variable; + * - *offset* - variable offset within data section, in bytes; + * - *byte_sz* - variable size, in bytes. + * + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz) +{ + struct btf_type *t; + struct btf_var_secinfo *v; + int sz; + + /* last type should be BTF_KIND_DATASEC */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_datasec(t)) + return -EINVAL; + + if (validate_type_id(var_type_id)) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_var_secinfo); + v = btf_add_type_mem(btf, sz); + if (!v) + return -ENOMEM; + + v->type = var_type_id; + v->offset = offset; + v->size = byte_sz; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + struct btf_ext_sec_setup_param { __u32 off; __u32 len; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index b387d0b61f1c..d6629a2e8ebf 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -77,6 +77,44 @@ LIBBPF_API struct btf *libbpf_find_kernel_btf(void); LIBBPF_API int btf__find_str(struct btf *btf, const char *s); LIBBPF_API int btf__add_str(struct btf *btf, const char *s); +LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding); +LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_array(struct btf *btf, + int index_type_id, int elem_type_id, __u32 nr_elems); +/* struct/union construction APIs */ +LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz); +LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz); +LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id, + __u32 bit_offset, __u32 bit_size); + +/* enum construction APIs */ +LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz); +LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value); + +enum btf_fwd_kind { + BTF_FWD_STRUCT = 0, + BTF_FWD_UNION = 1, + BTF_FWD_ENUM = 2, +}; + +LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind); +LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id); +LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id); + +/* func and func_proto construction APIs */ +LIBBPF_API int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id); +LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id); +LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id); + +/* var & datasec construction APIs */ +LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id); +LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz); +LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id, + __u32 offset, __u32 byte_sz); + struct btf_dedup_opts { unsigned int dedup_table_size; bool dont_resolve_fwds; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index d02d8f51e34f..0216ee6fdc2b 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -305,7 +305,26 @@ LIBBPF_0.2.0 { bpf_prog_bind_map; bpf_prog_test_run_opts; bpf_program__section_name; + btf__add_array; + btf__add_const; + btf__add_enum; + btf__add_enum_value; + btf__add_datasec; + btf__add_datasec_var_info; + btf__add_field; + btf__add_func; + btf__add_func_param; + btf__add_func_proto; + btf__add_fwd; + btf__add_int; + btf__add_ptr; + btf__add_restrict; btf__add_str; + btf__add_struct; + btf__add_typedef; + btf__add_union; + btf__add_var; + btf__add_volatile; btf__find_str; btf__new_empty; perf_buffer__buffer_cnt; -- cgit v1.2.3 From f86ed050bcee3b7daa420eb31a8b6d079701caab Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 28 Sep 2020 19:05:31 -0700 Subject: libbpf: Add btf__str_by_offset() as a more generic variant of name_by_offset BTF strings are used not just for names, they can be arbitrary strings used for CO-RE relocations, line/func infos, etc. Thus "name_by_offset" terminology is too specific and might be misleading. Instead, introduce btf__str_by_offset() API which uses generic string terminology. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200929020533.711288-3-andriin@fb.com --- tools/lib/bpf/btf.c | 7 ++++++- tools/lib/bpf/btf.h | 1 + tools/lib/bpf/libbpf.map | 1 + 3 files changed, 8 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7533088b2524..2d0b1e12f50e 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1025,7 +1025,7 @@ const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) return btf->raw_data; } -const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +const char *btf__str_by_offset(const struct btf *btf, __u32 offset) { if (offset < btf->hdr->str_len) return btf->strs_data + offset; @@ -1033,6 +1033,11 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset) return NULL; } +const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +{ + return btf__str_by_offset(btf, offset); +} + int btf__get_from_id(__u32 id, struct btf **btf) { struct bpf_btf_info btf_info = { 0 }; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index d6629a2e8ebf..f7dec0144c3c 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -49,6 +49,7 @@ LIBBPF_API int btf__fd(const struct btf *btf); LIBBPF_API void btf__set_fd(struct btf *btf, int fd); LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size); LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); +LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset); LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, __u32 expected_key_size, diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 0216ee6fdc2b..6b10ebad69c6 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -327,6 +327,7 @@ LIBBPF_0.2.0 { btf__add_volatile; btf__find_str; btf__new_empty; + btf__str_by_offset; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; perf_buffer__epoll_fd; -- cgit v1.2.3 From 9141f75a3279bab4a7d761c6050d96777b646767 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 28 Sep 2020 19:05:32 -0700 Subject: selftests/bpf: Test BTF writing APIs Add selftests for BTF writer APIs. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200929020533.711288-4-andriin@fb.com --- tools/lib/bpf/btf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 2d0b1e12f50e..c25f49fad5a6 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -31,10 +31,10 @@ struct btf { __u32 raw_size; /* - * When BTF is loaded from ELF or raw memory it is stored - * in contiguous memory block, pointed to by raw_data pointer, and - * hdr, types_data, and strs_data point inside that memory region to - * respective parts of BTF representation: + * When BTF is loaded from an ELF or raw memory it is stored + * in a contiguous memory block. The hdr, type_data, and, strs_data + * point inside that memory region to their respective parts of BTF + * representation: * * +--------------------------------+ * | Header | Types | Strings | -- cgit v1.2.3 From 3289959b97cac205df006fc79c88f042bf2765ab Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 28 Sep 2020 21:30:45 -0700 Subject: libbpf: Support BTF loading and raw data output in both endianness Teach BTF to recognized wrong endianness and transparently convert it internally to host endianness. Original endianness of BTF will be preserved and used during btf__get_raw_data() to convert resulting raw data to the same endianness and a source raw_data. This means that little-endian host can parse big-endian BTF with no issues, all the type data will be presented to the client application in native endianness, but when it's time for emitting BTF to persist it in a file (e.g., after BTF deduplication), original non-native endianness will be preserved and stored. It's possible to query original endianness of BTF data with new btf__endianness() API. It's also possible to override desired output endianness with btf__set_endianness(), so that if application needs to load, say, big-endian BTF and store it as little-endian BTF, it's possible to manually override this. If btf__set_endianness() was used to change endianness, btf__endianness() will reflect overridden endianness. Given there are no known use cases for supporting cross-endianness for .BTF.ext, loading .BTF.ext in non-native endianness is not supported. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200929043046.1324350-3-andriin@fb.com --- tools/lib/bpf/btf.c | 310 +++++++++++++++++++++++++++++++++++++---------- tools/lib/bpf/btf.h | 7 ++ tools/lib/bpf/libbpf.map | 2 + 3 files changed, 255 insertions(+), 64 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index c25f49fad5a6..e1dbd766c698 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) /* Copyright (c) 2018 Facebook */ +#include #include #include #include @@ -27,8 +28,13 @@ static struct btf_type btf_void; struct btf { + /* raw BTF data in native endianness */ void *raw_data; + /* raw BTF data in non-native endianness */ + void *raw_data_swapped; __u32 raw_size; + /* whether target endianness differs from the native one */ + bool swapped_endian; /* * When BTF is loaded from an ELF or raw memory it is stored @@ -153,9 +159,19 @@ static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) return 0; } +static void btf_bswap_hdr(struct btf_header *h) +{ + h->magic = bswap_16(h->magic); + h->hdr_len = bswap_32(h->hdr_len); + h->type_off = bswap_32(h->type_off); + h->type_len = bswap_32(h->type_len); + h->str_off = bswap_32(h->str_off); + h->str_len = bswap_32(h->str_len); +} + static int btf_parse_hdr(struct btf *btf) { - const struct btf_header *hdr = btf->hdr; + struct btf_header *hdr = btf->hdr; __u32 meta_left; if (btf->raw_size < sizeof(struct btf_header)) { @@ -163,21 +179,19 @@ static int btf_parse_hdr(struct btf *btf) return -EINVAL; } - if (hdr->magic != BTF_MAGIC) { + if (hdr->magic == bswap_16(BTF_MAGIC)) { + btf->swapped_endian = true; + if (bswap_32(hdr->hdr_len) != sizeof(struct btf_header)) { + pr_warn("Can't load BTF with non-native endianness due to unsupported header length %u\n", + bswap_32(hdr->hdr_len)); + return -ENOTSUP; + } + btf_bswap_hdr(hdr); + } else if (hdr->magic != BTF_MAGIC) { pr_debug("Invalid BTF magic:%x\n", hdr->magic); return -EINVAL; } - if (hdr->version != BTF_VERSION) { - pr_debug("Unsupported BTF version:%u\n", hdr->version); - return -ENOTSUP; - } - - if (hdr->flags) { - pr_debug("Unsupported BTF flags:%x\n", hdr->flags); - return -ENOTSUP; - } - meta_left = btf->raw_size - sizeof(*hdr); if (!meta_left) { pr_debug("BTF has no data\n"); @@ -224,7 +238,7 @@ static int btf_parse_str_sec(struct btf *btf) static int btf_type_size(const struct btf_type *t) { - int base_size = sizeof(struct btf_type); + const int base_size = sizeof(struct btf_type); __u16 vlen = btf_vlen(t); switch (btf_kind(t)) { @@ -257,12 +271,83 @@ static int btf_type_size(const struct btf_type *t) } } +static void btf_bswap_type_base(struct btf_type *t) +{ + t->name_off = bswap_32(t->name_off); + t->info = bswap_32(t->info); + t->type = bswap_32(t->type); +} + +static int btf_bswap_type_rest(struct btf_type *t) +{ + struct btf_var_secinfo *v; + struct btf_member *m; + struct btf_array *a; + struct btf_param *p; + struct btf_enum *e; + __u16 vlen = btf_vlen(t); + int i; + + switch (btf_kind(t)) { + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + return 0; + case BTF_KIND_INT: + *(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1)); + return 0; + case BTF_KIND_ENUM: + for (i = 0, e = btf_enum(t); i < vlen; i++, e++) { + e->name_off = bswap_32(e->name_off); + e->val = bswap_32(e->val); + } + return 0; + case BTF_KIND_ARRAY: + a = btf_array(t); + a->type = bswap_32(a->type); + a->index_type = bswap_32(a->index_type); + a->nelems = bswap_32(a->nelems); + return 0; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + for (i = 0, m = btf_members(t); i < vlen; i++, m++) { + m->name_off = bswap_32(m->name_off); + m->type = bswap_32(m->type); + m->offset = bswap_32(m->offset); + } + return 0; + case BTF_KIND_FUNC_PROTO: + for (i = 0, p = btf_params(t); i < vlen; i++, p++) { + p->name_off = bswap_32(p->name_off); + p->type = bswap_32(p->type); + } + return 0; + case BTF_KIND_VAR: + btf_var(t)->linkage = bswap_32(btf_var(t)->linkage); + return 0; + case BTF_KIND_DATASEC: + for (i = 0, v = btf_var_secinfos(t); i < vlen; i++, v++) { + v->type = bswap_32(v->type); + v->offset = bswap_32(v->offset); + v->size = bswap_32(v->size); + } + return 0; + default: + pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); + return -EINVAL; + } +} + static int btf_parse_type_sec(struct btf *btf) { struct btf_header *hdr = btf->hdr; void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; - int err, type_size; + int err, i, type_size; /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), * so ensure we can never properly use its offset from index by @@ -272,19 +357,36 @@ static int btf_parse_type_sec(struct btf *btf) if (err) return err; - while (next_type < end_type) { - err = btf_add_type_idx_entry(btf, next_type - btf->types_data); - if (err) - return err; + while (next_type + sizeof(struct btf_type) <= end_type) { + i++; + + if (btf->swapped_endian) + btf_bswap_type_base(next_type); type_size = btf_type_size(next_type); if (type_size < 0) return type_size; + if (next_type + type_size > end_type) { + pr_warn("BTF type [%d] is malformed\n", i); + return -EINVAL; + } + + if (btf->swapped_endian && btf_bswap_type_rest(next_type)) + return -EINVAL; + + err = btf_add_type_idx_entry(btf, next_type - btf->types_data); + if (err) + return err; next_type += type_size; btf->nr_types++; } + if (next_type != end_type) { + pr_warn("BTF types data is malformed\n"); + return -EINVAL; + } + return 0; } @@ -373,6 +475,38 @@ int btf__set_pointer_size(struct btf *btf, size_t ptr_sz) return 0; } +static bool is_host_big_endian(void) +{ +#if __BYTE_ORDER == __LITTLE_ENDIAN + return false; +#elif __BYTE_ORDER == __BIG_ENDIAN + return true; +#else +# error "Unrecognized __BYTE_ORDER__" +#endif +} + +enum btf_endianness btf__endianness(const struct btf *btf) +{ + if (is_host_big_endian()) + return btf->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN; + else + return btf->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN; +} + +int btf__set_endianness(struct btf *btf, enum btf_endianness endian) +{ + if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN) + return -EINVAL; + + btf->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN); + if (!btf->swapped_endian) { + free(btf->raw_data_swapped); + btf->raw_data_swapped = NULL; + } + return 0; +} + static bool btf_type_is_void(const struct btf_type *t) { return t == &btf_void || btf_is_fwd(t); @@ -561,6 +695,7 @@ void btf__free(struct btf *btf) free(btf->strs_data); } free(btf->raw_data); + free(btf->raw_data_swapped); free(btf->type_offs); free(btf); } @@ -572,8 +707,10 @@ struct btf *btf__new_empty(void) btf = calloc(1, sizeof(*btf)); if (!btf) return ERR_PTR(-ENOMEM); + btf->fd = -1; btf->ptr_sz = sizeof(void *); + btf->swapped_endian = false; /* +1 for empty string at offset 0 */ btf->raw_size = sizeof(struct btf_header) + 1; @@ -604,8 +741,6 @@ struct btf *btf__new(const void *data, __u32 size) if (!btf) return ERR_PTR(-ENOMEM); - btf->fd = -1; - btf->raw_data = malloc(size); if (!btf->raw_data) { err = -ENOMEM; @@ -624,6 +759,10 @@ struct btf *btf__new(const void *data, __u32 size) err = btf_parse_str_sec(btf); err = err ?: btf_parse_type_sec(btf); + if (err) + goto done; + + btf->fd = -1; done: if (err) { @@ -634,17 +773,6 @@ done: return btf; } -static bool btf_check_endianness(const GElf_Ehdr *ehdr) -{ -#if __BYTE_ORDER == __LITTLE_ENDIAN - return ehdr->e_ident[EI_DATA] == ELFDATA2LSB; -#elif __BYTE_ORDER == __BIG_ENDIAN - return ehdr->e_ident[EI_DATA] == ELFDATA2MSB; -#else -# error "Unrecognized __BYTE_ORDER__" -#endif -} - struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) { Elf_Data *btf_data = NULL, *btf_ext_data = NULL; @@ -677,10 +805,6 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) pr_warn("failed to get EHDR from %s\n", path); goto done; } - if (!btf_check_endianness(&ehdr)) { - pr_warn("non-native ELF endianness is not supported\n"); - goto done; - } if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); goto done; @@ -792,7 +916,7 @@ struct btf *btf__parse_raw(const char *path) err = -EIO; goto err_out; } - if (magic != BTF_MAGIC) { + if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) { /* definitely not a raw BTF */ err = -EPROTO; goto err_out; @@ -942,11 +1066,13 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf) return err; } +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); + int btf__load(struct btf *btf) { __u32 log_buf_size = 0, raw_size; char *log_buf = NULL; - const void *raw_data; + void *raw_data; int err = 0; if (btf->fd >= 0) @@ -961,11 +1087,14 @@ retry_load: *log_buf = 0; } - raw_data = btf__get_raw_data(btf, &raw_size); + raw_data = btf_get_raw_data(btf, &raw_size, false); if (!raw_data) { err = -ENOMEM; goto done; } + /* cache native raw data representation */ + btf->raw_size = raw_size; + btf->raw_data = raw_data; btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false); if (btf->fd < 0) { @@ -998,31 +1127,73 @@ void btf__set_fd(struct btf *btf, int fd) btf->fd = fd; } -const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian) { - struct btf *btf = (struct btf *)btf_ro; + struct btf_header *hdr = btf->hdr; + struct btf_type *t; + void *data, *p; + __u32 data_sz; + int i; - if (!btf->raw_data) { - struct btf_header *hdr = btf->hdr; - void *data; + data = swap_endian ? btf->raw_data_swapped : btf->raw_data; + if (data) { + *size = btf->raw_size; + return data; + } + + data_sz = hdr->hdr_len + hdr->type_len + hdr->str_len; + data = calloc(1, data_sz); + if (!data) + return NULL; + p = data; + + memcpy(p, hdr, hdr->hdr_len); + if (swap_endian) + btf_bswap_hdr(p); + p += hdr->hdr_len; + + memcpy(p, btf->types_data, hdr->type_len); + if (swap_endian) { + for (i = 1; i <= btf->nr_types; i++) { + t = p + btf->type_offs[i]; + /* btf_bswap_type_rest() relies on native t->info, so + * we swap base type info after we swapped all the + * additional information + */ + if (btf_bswap_type_rest(t)) + goto err_out; + btf_bswap_type_base(t); + } + } + p += hdr->type_len; + + memcpy(p, btf->strs_data, hdr->str_len); + p += hdr->str_len; - btf->raw_size = hdr->hdr_len + hdr->type_len + hdr->str_len; - btf->raw_data = calloc(1, btf->raw_size); - if (!btf->raw_data) - return NULL; - data = btf->raw_data; + *size = data_sz; + return data; +err_out: + free(data); + return NULL; +} - memcpy(data, hdr, hdr->hdr_len); - data += hdr->hdr_len; +const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) +{ + struct btf *btf = (struct btf *)btf_ro; + __u32 data_sz; + void *data; - memcpy(data, btf->types_data, hdr->type_len); - data += hdr->type_len; + data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian); + if (!data) + return NULL; - memcpy(data, btf->strs_data, hdr->str_len); - data += hdr->str_len; - } - *size = btf->raw_size; - return btf->raw_data; + btf->raw_size = data_sz; + if (btf->swapped_endian) + btf->raw_data_swapped = data; + else + btf->raw_data = data; + *size = data_sz; + return data; } const char *btf__str_by_offset(const struct btf *btf, __u32 offset) @@ -1190,6 +1361,18 @@ static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx) return strcmp(str1, str2) == 0; } +static void btf_invalidate_raw_data(struct btf *btf) +{ + if (btf->raw_data) { + free(btf->raw_data); + btf->raw_data = NULL; + } + if (btf->raw_data_swapped) { + free(btf->raw_data_swapped); + btf->raw_data_swapped = NULL; + } +} + /* Ensure BTF is ready to be modified (by splitting into a three memory * regions for header, types, and strings). Also invalidate cached * raw_data, if any. @@ -1203,10 +1386,7 @@ static int btf_ensure_modifiable(struct btf *btf) if (btf_is_modifiable(btf)) { /* any BTF modification invalidates raw_data */ - if (btf->raw_data) { - free(btf->raw_data); - btf->raw_data = NULL; - } + btf_invalidate_raw_data(btf); return 0; } @@ -1254,8 +1434,7 @@ static int btf_ensure_modifiable(struct btf *btf) btf->strs_deduped = btf->hdr->str_len <= 1; /* invalidate raw_data representation */ - free(btf->raw_data); - btf->raw_data = NULL; + btf_invalidate_raw_data(btf); return 0; @@ -2275,7 +2454,10 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) return -EINVAL; } - if (hdr->magic != BTF_MAGIC) { + if (hdr->magic == bswap_16(BTF_MAGIC)) { + pr_warn("BTF.ext in non-native endianness is not supported\n"); + return -ENOTSUP; + } else if (hdr->magic != BTF_MAGIC) { pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic); return -EINVAL; } diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index f7dec0144c3c..57247240a20a 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -25,6 +25,11 @@ struct btf_type; struct bpf_object; +enum btf_endianness { + BTF_LITTLE_ENDIAN = 0, + BTF_BIG_ENDIAN = 1, +}; + LIBBPF_API void btf__free(struct btf *btf); LIBBPF_API struct btf *btf__new(const void *data, __u32 size); LIBBPF_API struct btf *btf__new_empty(void); @@ -42,6 +47,8 @@ LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 id); LIBBPF_API size_t btf__pointer_size(const struct btf *btf); LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz); +LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf); +LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian); LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 6b10ebad69c6..f7a8ff37ef04 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -325,8 +325,10 @@ LIBBPF_0.2.0 { btf__add_union; btf__add_var; btf__add_volatile; + btf__endianness; btf__find_str; btf__new_empty; + btf__set_endianness; btf__str_by_offset; perf_buffer__buffer_cnt; perf_buffer__buffer_fd; -- cgit v1.2.3 From a535909142bf2a6f3a95cabbb8b38ce3860c4807 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Tue, 29 Sep 2020 14:45:53 +0200 Subject: libbpf: Add support for freplace attachment in bpf_link_create MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds support for supplying a target btf ID for the bpf_link_create() operation, and adds a new bpf_program__attach_freplace() high-level API for attaching freplace functions with a target. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/160138355387.48470.18026176785351166890.stgit@toke.dk --- tools/lib/bpf/bpf.c | 18 +++++++++++++++--- tools/lib/bpf/bpf.h | 3 ++- tools/lib/bpf/libbpf.c | 44 +++++++++++++++++++++++++++++++++++++++----- tools/lib/bpf/libbpf.h | 3 +++ tools/lib/bpf/libbpf.map | 1 + 5 files changed, 60 insertions(+), 9 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 70575a37aa14..d27e34133973 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -586,19 +586,31 @@ int bpf_link_create(int prog_fd, int target_fd, enum bpf_attach_type attach_type, const struct bpf_link_create_opts *opts) { + __u32 target_btf_id, iter_info_len; union bpf_attr attr; if (!OPTS_VALID(opts, bpf_link_create_opts)) return -EINVAL; + iter_info_len = OPTS_GET(opts, iter_info_len, 0); + target_btf_id = OPTS_GET(opts, target_btf_id, 0); + + if (iter_info_len && target_btf_id) + return -EINVAL; + memset(&attr, 0, sizeof(attr)); attr.link_create.prog_fd = prog_fd; attr.link_create.target_fd = target_fd; attr.link_create.attach_type = attach_type; attr.link_create.flags = OPTS_GET(opts, flags, 0); - attr.link_create.iter_info = - ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0)); - attr.link_create.iter_info_len = OPTS_GET(opts, iter_info_len, 0); + + if (iter_info_len) { + attr.link_create.iter_info = + ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0)); + attr.link_create.iter_info_len = iter_info_len; + } else if (target_btf_id) { + attr.link_create.target_btf_id = target_btf_id; + } return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr)); } diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 16806810a53c..875dde20d56e 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -174,8 +174,9 @@ struct bpf_link_create_opts { __u32 flags; union bpf_iter_link_info *iter_info; __u32 iter_info_len; + __u32 target_btf_id; }; -#define bpf_link_create_opts__last_field iter_info_len +#define bpf_link_create_opts__last_field target_btf_id LIBBPF_API int bpf_link_create(int prog_fd, int target_fd, enum bpf_attach_type attach_type, diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 32dc444224d8..a4f55f8a460d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9390,9 +9390,11 @@ static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, } static struct bpf_link * -bpf_program__attach_fd(struct bpf_program *prog, int target_fd, +bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id, const char *target_name) { + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts, + .target_btf_id = btf_id); enum bpf_attach_type attach_type; char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; @@ -9410,7 +9412,7 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd, link->detach = &bpf_link__detach_fd; attach_type = bpf_program__get_expected_attach_type(prog); - link_fd = bpf_link_create(prog_fd, target_fd, attach_type, NULL); + link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts); if (link_fd < 0) { link_fd = -errno; free(link); @@ -9426,19 +9428,51 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd, struct bpf_link * bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) { - return bpf_program__attach_fd(prog, cgroup_fd, "cgroup"); + return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup"); } struct bpf_link * bpf_program__attach_netns(struct bpf_program *prog, int netns_fd) { - return bpf_program__attach_fd(prog, netns_fd, "netns"); + return bpf_program__attach_fd(prog, netns_fd, 0, "netns"); } struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex) { /* target_fd/target_ifindex use the same field in LINK_CREATE */ - return bpf_program__attach_fd(prog, ifindex, "xdp"); + return bpf_program__attach_fd(prog, ifindex, 0, "xdp"); +} + +struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog, + int target_fd, + const char *attach_func_name) +{ + int btf_id; + + if (!!target_fd != !!attach_func_name) { + pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n", + prog->name); + return ERR_PTR(-EINVAL); + } + + if (prog->type != BPF_PROG_TYPE_EXT) { + pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace", + prog->name); + return ERR_PTR(-EINVAL); + } + + if (target_fd) { + btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); + if (btf_id < 0) + return ERR_PTR(btf_id); + + return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace"); + } else { + /* no target, so use raw_tracepoint_open for compatibility + * with old kernels + */ + return bpf_program__attach_trace(prog); + } } struct bpf_link * diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index a750f67a23f6..6909ee81113a 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -261,6 +261,9 @@ LIBBPF_API struct bpf_link * bpf_program__attach_netns(struct bpf_program *prog, int netns_fd); LIBBPF_API struct bpf_link * bpf_program__attach_xdp(struct bpf_program *prog, int ifindex); +LIBBPF_API struct bpf_link * +bpf_program__attach_freplace(struct bpf_program *prog, + int target_fd, const char *attach_func_name); struct bpf_map; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index f7a8ff37ef04..4ebfadf45b47 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -304,6 +304,7 @@ LIBBPF_0.2.0 { global: bpf_prog_bind_map; bpf_prog_test_run_opts; + bpf_program__attach_freplace; bpf_program__section_name; btf__add_array; btf__add_const; -- cgit v1.2.3 From 33433913459a6bfbfa808c202d6f5490aa43d7a7 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 29 Sep 2020 15:06:02 -0700 Subject: libbpf: Fix uninitialized variable in btf_parse_type_sec Fix obvious unitialized variable use that wasn't reported by compiler. libbpf Makefile changes to catch such errors are added separately. Fixes: 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200929220604.833631-1-andriin@fb.com --- tools/lib/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index e1dbd766c698..398b1f345b3c 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -347,7 +347,7 @@ static int btf_parse_type_sec(struct btf *btf) struct btf_header *hdr = btf->hdr; void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; - int err, i, type_size; + int err, i = 0, type_size; /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), * so ensure we can never properly use its offset from index by -- cgit v1.2.3 From 0a62291d697f1d2882650f5b9f97d331ad9a505b Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 29 Sep 2020 15:06:03 -0700 Subject: libbpf: Compile libbpf under -O2 level by default and catch extra warnings For some reason compiler doesn't complain about uninitialized variable, fixed in previous patch, if libbpf is compiled without -O2 optimization level. So do compile it with -O2 and never let similar issue slip by again. -Wall is added unconditionally, so no need to specify it again. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200929220604.833631-2-andriin@fb.com --- tools/lib/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index f43249696d9f..70cb44efe8cb 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -98,7 +98,7 @@ PC_FILE = libbpf.pc ifdef EXTRA_CFLAGS CFLAGS := $(EXTRA_CFLAGS) else - CFLAGS := -g -Wall + CFLAGS := -g -O2 endif # Append required CFLAGS -- cgit v1.2.3 From b0efc216f577997bf563d76d51673ed79c3d5f71 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 29 Sep 2020 15:06:04 -0700 Subject: libbpf: Compile in PIC mode only for shared library case Libbpf compiles .o's for static and shared library modes separately, so no need to specify -fPIC for both. Keep it only for shared library mode. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200929220604.833631-3-andriin@fb.com --- tools/lib/bpf/Makefile | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 70cb44efe8cb..5f9abed3e226 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -104,13 +104,12 @@ endif # Append required CFLAGS override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum override CFLAGS += -Werror -Wall -override CFLAGS += -fPIC override CFLAGS += $(INCLUDES) override CFLAGS += -fvisibility=hidden override CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 # flags specific for shared library -SHLIB_FLAGS := -DSHARED +SHLIB_FLAGS := -DSHARED -fPIC ifeq ($(VERBOSE),1) Q = -- cgit v1.2.3 From 0e9f6841f664f801a69d27f765dc70b8a93e1959 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 30 Sep 2020 17:18:18 +0200 Subject: bpf, libbpf: Add bpf_tail_call_static helper for bpf programs Port of tail_call_static() helper function from Cilium's BPF code base [0] to libbpf, so others can easily consume it as well. We've been using this in production code for some time now. The main idea is that we guarantee that the kernel's BPF infrastructure and JIT (here: x86_64) can patch the JITed BPF insns with direct jumps instead of having to fall back to using expensive retpolines. By using inline asm, we guarantee that the compiler won't merge the call from different paths with potentially different content of r2/r3. We're also using Cilium's __throw_build_bug() macro (here as: __bpf_unreachable()) in different places as a neat trick to trigger compilation errors when compiler does not remove code at compilation time. This works for the BPF back end as it does not implement the __builtin_trap(). [0] https://github.com/cilium/cilium/commit/f5537c26020d5297b70936c6b7d03a1e412a1035 Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/1656a082e077552eb46642d513b4a6bde9a7dd01.1601477936.git.daniel@iogearbox.net --- tools/lib/bpf/bpf_helpers.h | 46 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 1106777df00b..2bdb7d6dbad2 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -53,6 +53,52 @@ }) #endif +/* + * Helper macro to throw a compilation error if __bpf_unreachable() gets + * built into the resulting code. This works given BPF back end does not + * implement __builtin_trap(). This is useful to assert that certain paths + * of the program code are never used and hence eliminated by the compiler. + * + * For example, consider a switch statement that covers known cases used by + * the program. __bpf_unreachable() can then reside in the default case. If + * the program gets extended such that a case is not covered in the switch + * statement, then it will throw a build error due to the default case not + * being compiled out. + */ +#ifndef __bpf_unreachable +# define __bpf_unreachable() __builtin_trap() +#endif + +/* + * Helper function to perform a tail call with a constant/immediate map slot. + */ +static __always_inline void +bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) +{ + if (!__builtin_constant_p(slot)) + __bpf_unreachable(); + + /* + * Provide a hard guarantee that LLVM won't optimize setting r2 (map + * pointer) and r3 (constant map index) from _different paths_ ending + * up at the _same_ call insn as otherwise we won't be able to use the + * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel + * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key + * tracking for prog array pokes") for details on verifier tracking. + * + * Note on clobber list: we need to stay in-line with BPF calling + * convention, so even if we don't end up using r0, r4, r5, we need + * to mark them as clobber so that LLVM doesn't end up using them + * before / after the call. + */ + asm volatile("r1 = %[ctx]\n\t" + "r2 = %[map]\n\t" + "r3 = %[slot]\n\t" + "call 12" + :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot) + : "r0", "r1", "r2", "r3", "r4", "r5"); +} + /* * Helper structure used by eBPF C program * to describe BPF map attributes to libbpf loader -- cgit v1.2.3 From 9c6c5c48d7e9c00c541e0f1a5cea3a96767e825c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 29 Sep 2020 16:28:40 -0700 Subject: libbpf: Make btf_dump work with modifiable BTF Ensure that btf_dump can accommodate new BTF types being appended to BTF instance after struct btf_dump was created. This came up during attemp to use btf_dump for raw type dumping in selftests, but given changes are not excessive, it's good to not have any gotchas in API usage, so I decided to support such use case in general. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200929232843.1249318-2-andriin@fb.com --- tools/lib/bpf/btf.c | 17 ++++++++++ tools/lib/bpf/btf_dump.c | 69 ++++++++++++++++++++++++++++------------- tools/lib/bpf/libbpf_internal.h | 1 + 3 files changed, 65 insertions(+), 22 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 398b1f345b3c..231b07203e3d 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -146,6 +146,23 @@ void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, return new_data + cur_cnt * elem_sz; } +/* Ensure given dynamically allocated memory region has enough allocated space + * to accommodate *need_cnt* elements of size *elem_sz* bytes each + */ +int btf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt) +{ + void *p; + + if (need_cnt <= *cap_cnt) + return 0; + + p = btf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt); + if (!p) + return -ENOMEM; + + return 0; +} + static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) { __u32 *p; diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 91310e528a3a..2f9d685bd522 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -60,11 +60,14 @@ struct btf_dump { struct btf_dump_opts opts; int ptr_sz; bool strip_mods; + int last_id; /* per-type auxiliary state */ struct btf_dump_type_aux_state *type_states; + size_t type_states_cap; /* per-type optional cached unique name, must be freed, if present */ const char **cached_names; + size_t cached_names_cap; /* topo-sorted list of dependent type definitions */ __u32 *emit_queue; @@ -113,6 +116,7 @@ static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...) } static int btf_dump_mark_referenced(struct btf_dump *d); +static int btf_dump_resize(struct btf_dump *d); struct btf_dump *btf_dump__new(const struct btf *btf, const struct btf_ext *btf_ext, @@ -144,25 +148,8 @@ struct btf_dump *btf_dump__new(const struct btf *btf, d->ident_names = NULL; goto err; } - d->type_states = calloc(1 + btf__get_nr_types(d->btf), - sizeof(d->type_states[0])); - if (!d->type_states) { - err = -ENOMEM; - goto err; - } - d->cached_names = calloc(1 + btf__get_nr_types(d->btf), - sizeof(d->cached_names[0])); - if (!d->cached_names) { - err = -ENOMEM; - goto err; - } - /* VOID is special */ - d->type_states[0].order_state = ORDERED; - d->type_states[0].emit_state = EMITTED; - - /* eagerly determine referenced types for anon enums */ - err = btf_dump_mark_referenced(d); + err = btf_dump_resize(d); if (err) goto err; @@ -172,9 +159,38 @@ err: return ERR_PTR(err); } +static int btf_dump_resize(struct btf_dump *d) +{ + int err, last_id = btf__get_nr_types(d->btf); + + if (last_id <= d->last_id) + return 0; + + if (btf_ensure_mem((void **)&d->type_states, &d->type_states_cap, + sizeof(*d->type_states), last_id + 1)) + return -ENOMEM; + if (btf_ensure_mem((void **)&d->cached_names, &d->cached_names_cap, + sizeof(*d->cached_names), last_id + 1)) + return -ENOMEM; + + if (d->last_id == 0) { + /* VOID is special */ + d->type_states[0].order_state = ORDERED; + d->type_states[0].emit_state = EMITTED; + } + + /* eagerly determine referenced types for anon enums */ + err = btf_dump_mark_referenced(d); + if (err) + return err; + + d->last_id = last_id; + return 0; +} + void btf_dump__free(struct btf_dump *d) { - int i, cnt; + int i; if (IS_ERR_OR_NULL(d)) return; @@ -182,7 +198,7 @@ void btf_dump__free(struct btf_dump *d) free(d->type_states); if (d->cached_names) { /* any set cached name is owned by us and should be freed */ - for (i = 0, cnt = btf__get_nr_types(d->btf); i <= cnt; i++) { + for (i = 0; i <= d->last_id; i++) { if (d->cached_names[i]) free((void *)d->cached_names[i]); } @@ -222,6 +238,10 @@ int btf_dump__dump_type(struct btf_dump *d, __u32 id) if (id > btf__get_nr_types(d->btf)) return -EINVAL; + err = btf_dump_resize(d); + if (err) + return err; + d->emit_queue_cnt = 0; err = btf_dump_order_type(d, id, false); if (err < 0) @@ -251,7 +271,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d) const struct btf_type *t; __u16 vlen; - for (i = 1; i <= n; i++) { + for (i = d->last_id + 1; i <= n; i++) { t = btf__type_by_id(d->btf, i); vlen = btf_vlen(t); @@ -306,6 +326,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d) } return 0; } + static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id) { __u32 *new_queue; @@ -1049,11 +1070,15 @@ int btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, const struct btf_dump_emit_type_decl_opts *opts) { const char *fname; - int lvl; + int lvl, err; if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts)) return -EINVAL; + err = btf_dump_resize(d); + if (err) + return -EINVAL; + fname = OPTS_GET(opts, field_name, ""); lvl = OPTS_GET(opts, indent_level, 0); d->strip_mods = OPTS_GET(opts, strip_mods, false); diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index eed5b624a784..d99bc847bf84 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -107,6 +107,7 @@ static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t cur_cnt, size_t max_cnt, size_t add_cnt); +int btf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); static inline bool libbpf_validate_opts(const char *opts, size_t opts_sz, size_t user_sz, -- cgit v1.2.3 From d370bbe1214381f444cbd9cdf3b8647223abb536 Mon Sep 17 00:00:00 2001 From: Hao Luo Date: Tue, 29 Sep 2020 16:50:45 -0700 Subject: bpf/libbpf: BTF support for typed ksyms If a ksym is defined with a type, libbpf will try to find the ksym's btf information from kernel btf. If a valid btf entry for the ksym is found, libbpf can pass in the found btf id to the verifier, which validates the ksym's type and value. Typeless ksyms (i.e. those defined as 'void') will not have such btf_id, but it has the symbol's address (read from kallsyms) and its value is treated as a raw pointer. Signed-off-by: Hao Luo Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200929235049.2533242-3-haoluo@google.com --- tools/lib/bpf/libbpf.c | 112 +++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 99 insertions(+), 13 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a4f55f8a460d..9b36c52b8511 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -390,6 +390,12 @@ struct extern_desc { } kcfg; struct { unsigned long long addr; + + /* target btf_id of the corresponding kernel var. */ + int vmlinux_btf_id; + + /* local btf_id of the ksym extern's type. */ + __u32 type_id; } ksym; }; }; @@ -2522,12 +2528,23 @@ static int bpf_object__load_vmlinux_btf(struct bpf_object *obj) { bool need_vmlinux_btf = false; struct bpf_program *prog; - int err; + int i, err; /* CO-RE relocations need kernel BTF */ if (obj->btf_ext && obj->btf_ext->core_relo_info.len) need_vmlinux_btf = true; + /* Support for typed ksyms needs kernel BTF */ + for (i = 0; i < obj->nr_extern; i++) { + const struct extern_desc *ext; + + ext = &obj->externs[i]; + if (ext->type == EXT_KSYM && ext->ksym.type_id) { + need_vmlinux_btf = true; + break; + } + } + bpf_object__for_each_program(prog, obj) { if (!prog->load) continue; @@ -3156,16 +3173,10 @@ static int bpf_object__collect_externs(struct bpf_object *obj) return -ENOTSUP; } } else if (strcmp(sec_name, KSYMS_SEC) == 0) { - const struct btf_type *vt; - ksym_sec = sec; ext->type = EXT_KSYM; - - vt = skip_mods_and_typedefs(obj->btf, t->type, NULL); - if (!btf_is_void(vt)) { - pr_warn("extern (ksym) '%s' is not typeless (void)\n", ext_name); - return -ENOTSUP; - } + skip_mods_and_typedefs(obj->btf, t->type, + &ext->ksym.type_id); } else { pr_warn("unrecognized extern section '%s'\n", sec_name); return -ENOTSUP; @@ -5800,8 +5811,13 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) insn[0].imm = obj->maps[obj->kconfig_map_idx].fd; insn[1].imm = ext->kcfg.data_off; } else /* EXT_KSYM */ { - insn[0].imm = (__u32)ext->ksym.addr; - insn[1].imm = ext->ksym.addr >> 32; + if (ext->ksym.type_id) { /* typed ksyms */ + insn[0].src_reg = BPF_PSEUDO_BTF_ID; + insn[0].imm = ext->ksym.vmlinux_btf_id; + } else { /* typeless ksyms */ + insn[0].imm = (__u32)ext->ksym.addr; + insn[1].imm = ext->ksym.addr >> 32; + } } relo->processed = true; break; @@ -6933,10 +6949,72 @@ out: return err; } +static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) +{ + struct extern_desc *ext; + int i, id; + + for (i = 0; i < obj->nr_extern; i++) { + const struct btf_type *targ_var, *targ_type; + __u32 targ_type_id, local_type_id; + const char *targ_var_name; + int ret; + + ext = &obj->externs[i]; + if (ext->type != EXT_KSYM || !ext->ksym.type_id) + continue; + + id = btf__find_by_name_kind(obj->btf_vmlinux, ext->name, + BTF_KIND_VAR); + if (id <= 0) { + pr_warn("extern (ksym) '%s': failed to find BTF ID in vmlinux BTF.\n", + ext->name); + return -ESRCH; + } + + /* find local type_id */ + local_type_id = ext->ksym.type_id; + + /* find target type_id */ + targ_var = btf__type_by_id(obj->btf_vmlinux, id); + targ_var_name = btf__name_by_offset(obj->btf_vmlinux, + targ_var->name_off); + targ_type = skip_mods_and_typedefs(obj->btf_vmlinux, + targ_var->type, + &targ_type_id); + + ret = bpf_core_types_are_compat(obj->btf, local_type_id, + obj->btf_vmlinux, targ_type_id); + if (ret <= 0) { + const struct btf_type *local_type; + const char *targ_name, *local_name; + + local_type = btf__type_by_id(obj->btf, local_type_id); + local_name = btf__name_by_offset(obj->btf, + local_type->name_off); + targ_name = btf__name_by_offset(obj->btf_vmlinux, + targ_type->name_off); + + pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", + ext->name, local_type_id, + btf_kind_str(local_type), local_name, targ_type_id, + btf_kind_str(targ_type), targ_name); + return -EINVAL; + } + + ext->is_set = true; + ext->ksym.vmlinux_btf_id = id; + pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n", + ext->name, id, btf_kind_str(targ_var), targ_var_name); + } + return 0; +} + static int bpf_object__resolve_externs(struct bpf_object *obj, const char *extra_kconfig) { bool need_config = false, need_kallsyms = false; + bool need_vmlinux_btf = false; struct extern_desc *ext; void *kcfg_data = NULL; int err, i; @@ -6967,7 +7045,10 @@ static int bpf_object__resolve_externs(struct bpf_object *obj, strncmp(ext->name, "CONFIG_", 7) == 0) { need_config = true; } else if (ext->type == EXT_KSYM) { - need_kallsyms = true; + if (ext->ksym.type_id) + need_vmlinux_btf = true; + else + need_kallsyms = true; } else { pr_warn("unrecognized extern '%s'\n", ext->name); return -EINVAL; @@ -6996,6 +7077,11 @@ static int bpf_object__resolve_externs(struct bpf_object *obj, if (err) return -EINVAL; } + if (need_vmlinux_btf) { + err = bpf_object__resolve_ksyms_btf_id(obj); + if (err) + return -EINVAL; + } for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; @@ -7028,10 +7114,10 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr) } err = bpf_object__probe_loading(obj); + err = err ? : bpf_object__load_vmlinux_btf(obj); err = err ? : bpf_object__resolve_externs(obj, obj->kconfig); err = err ? : bpf_object__sanitize_and_load_btf(obj); err = err ? : bpf_object__sanitize_maps(obj); - err = err ? : bpf_object__load_vmlinux_btf(obj); err = err ? : bpf_object__init_kern_struct_ops_maps(obj); err = err ? : bpf_object__create_maps(obj); err = err ? : bpf_object__relocate(obj, attr->target_btf_path); -- cgit v1.2.3 From a0f2b7acb4b1d29127ff99c714233b973afd1411 Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Tue, 6 Oct 2020 10:13:43 +0800 Subject: libbpf: Close map fd if init map slots failed Previously we forgot to close the map fd if bpf_map_update_elem() failed during map slot init, which will leak map fd. Let's move map slot initialization to new function init_map_slots() to simplify the code. And close the map fd if init slot failed. Reported-by: Andrii Nakryiko Signed-off-by: Hangbin Liu Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20201006021345.3817033-2-liuhangbin@gmail.com --- tools/lib/bpf/libbpf.c | 55 +++++++++++++++++++++++++++++++------------------- 1 file changed, 34 insertions(+), 21 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 9b36c52b8511..7cec237d9d1f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4203,6 +4203,36 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) return 0; } +static int init_map_slots(struct bpf_map *map) +{ + const struct bpf_map *targ_map; + unsigned int i; + int fd, err; + + for (i = 0; i < map->init_slots_sz; i++) { + if (!map->init_slots[i]) + continue; + + targ_map = map->init_slots[i]; + fd = bpf_map__fd(targ_map); + err = bpf_map_update_elem(map->fd, &i, &fd, 0); + if (err) { + err = -errno; + pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n", + map->name, i, targ_map->name, + fd, err); + return err; + } + pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n", + map->name, i, targ_map->name, fd); + } + + zfree(&map->init_slots); + map->init_slots_sz = 0; + + return 0; +} + static int bpf_object__create_maps(struct bpf_object *obj) { @@ -4245,28 +4275,11 @@ bpf_object__create_maps(struct bpf_object *obj) } if (map->init_slots_sz) { - for (j = 0; j < map->init_slots_sz; j++) { - const struct bpf_map *targ_map; - int fd; - - if (!map->init_slots[j]) - continue; - - targ_map = map->init_slots[j]; - fd = bpf_map__fd(targ_map); - err = bpf_map_update_elem(map->fd, &j, &fd, 0); - if (err) { - err = -errno; - pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n", - map->name, j, targ_map->name, - fd, err); - goto err_out; - } - pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n", - map->name, j, targ_map->name, fd); + err = init_map_slots(map); + if (err < 0) { + zclose(map->fd); + goto err_out; } - zfree(&map->init_slots); - map->init_slots_sz = 0; } if (map->pin_path && !map->pinned) { -- cgit v1.2.3 From 2c193d32caee83322a8511a88ba0cd097bba73f1 Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Tue, 6 Oct 2020 10:13:44 +0800 Subject: libbpf: Check if pin_path was set even map fd exist Say a user reuse map fd after creating a map manually and set the pin_path, then load the object via libbpf. In libbpf bpf_object__create_maps(), bpf_object__reuse_map() will return 0 if there is no pinned map in map->pin_path. Then after checking if map fd exist, we should also check if pin_path was set and do bpf_map__pin() instead of continue the loop. Fix it by creating map if fd not exist and continue checking pin_path after that. Suggested-by: Andrii Nakryiko Signed-off-by: Hangbin Liu Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20201006021345.3817033-3-liuhangbin@gmail.com --- tools/lib/bpf/libbpf.c | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 7cec237d9d1f..9f90d1a686fd 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4256,29 +4256,28 @@ bpf_object__create_maps(struct bpf_object *obj) if (map->fd >= 0) { pr_debug("map '%s': skipping creation (preset fd=%d)\n", map->name, map->fd); - continue; - } - - err = bpf_object__create_map(obj, map); - if (err) - goto err_out; + } else { + err = bpf_object__create_map(obj, map); + if (err) + goto err_out; - pr_debug("map '%s': created successfully, fd=%d\n", map->name, - map->fd); + pr_debug("map '%s': created successfully, fd=%d\n", + map->name, map->fd); - if (bpf_map__is_internal(map)) { - err = bpf_object__populate_internal_map(obj, map); - if (err < 0) { - zclose(map->fd); - goto err_out; + if (bpf_map__is_internal(map)) { + err = bpf_object__populate_internal_map(obj, map); + if (err < 0) { + zclose(map->fd); + goto err_out; + } } - } - if (map->init_slots_sz) { - err = init_map_slots(map); - if (err < 0) { - zclose(map->fd); - goto err_out; + if (map->init_slots_sz) { + err = init_map_slots(map); + if (err < 0) { + zclose(map->fd); + goto err_out; + } } } -- cgit v1.2.3 From 8cee9107e72c93a52a7f2c58658c99887bdb05e0 Mon Sep 17 00:00:00 2001 From: Luigi Rizzo Date: Mon, 5 Oct 2020 15:45:28 -0700 Subject: bpf, libbpf: Use valid btf in bpf_program__set_attach_target bpf_program__set_attach_target(prog, fd, ...) will always fail when fd = 0 (attach to a kernel symbol) because obj->btf_vmlinux is NULL and there is no way to set it (at the moment btf_vmlinux is meant to be temporary storage for use in bpf_object__load_xattr()). Fix this by using libbpf_find_vmlinux_btf_id(). At some point we may want to opportunistically cache btf_vmlinux so it can be reused with multiple programs. Signed-off-by: Luigi Rizzo Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Acked-by: Petar Penkov Link: https://lore.kernel.org/bpf/20201005224528.389097-1-lrizzo@google.com --- tools/lib/bpf/libbpf.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 9f90d1a686fd..faec389c4849 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10451,9 +10451,8 @@ int bpf_program__set_attach_target(struct bpf_program *prog, btf_id = libbpf_find_prog_btf_id(attach_func_name, attach_prog_fd); else - btf_id = __find_vmlinux_btf_id(prog->obj->btf_vmlinux, - attach_func_name, - prog->expected_attach_type); + btf_id = libbpf_find_vmlinux_btf_id(attach_func_name, + prog->expected_attach_type); if (btf_id < 0) return btf_id; -- cgit v1.2.3 From 80348d8867c65e2c64ca78d82326e889550a24b6 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 7 Oct 2020 13:42:26 +0200 Subject: libbpf: Fix compatibility problem in xsk_socket__create Fix a compatibility problem when the old XDP_SHARED_UMEM mode is used together with the xsk_socket__create() call. In the old XDP_SHARED_UMEM mode, only sharing of the same device and queue id was allowed, and in this mode, the fill ring and completion ring were shared between the AF_XDP sockets. Therefore, it was perfectly fine to call the xsk_socket__create() API for each socket and not use the new xsk_socket__create_shared() API. This behavior was ruined by the commit introducing XDP_SHARED_UMEM support between different devices and/or queue ids. This patch restores the ability to use xsk_socket__create in these circumstances so that backward compatibility is not broken. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/1602070946-11154-1-git-send-email-magnus.karlsson@gmail.com --- tools/lib/bpf/xsk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 30b4ca5d2ac7..e3c98c007825 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -705,7 +705,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, struct xsk_ctx *ctx; int err, ifindex; - if (!umem || !xsk_ptr || !(rx || tx) || !fill || !comp) + if (!umem || !xsk_ptr || !(rx || tx)) return -EFAULT; xsk = calloc(1, sizeof(*xsk)); @@ -735,6 +735,11 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, ctx = xsk_get_ctx(umem, ifindex, queue_id); if (!ctx) { + if (!fill || !comp) { + err = -EFAULT; + goto out_socket; + } + ctx = xsk_create_ctx(xsk, umem, ifindex, ifname, queue_id, fill, comp); if (!ctx) { -- cgit v1.2.3 From 47f7cf6325f7d38e33d3dc38fa55bbe605f5b335 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 7 Oct 2020 17:10:21 -0700 Subject: libbpf: Skip CO-RE relocations for not loaded BPF programs Bypass CO-RE relocations step for BPF programs that are not going to be loaded. This allows to have BPF programs compiled in and disabled dynamically if kernel is not supposed to provide enough relocation information. In such case, there won't be unnecessary warnings about failed relocations. Fixes: d929758101fc ("libbpf: Support disabling auto-loading BPF programs") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20201008001025.292064-2-andrii@kernel.org --- tools/lib/bpf/libbpf.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index faec389c4849..07d62771472f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5765,6 +5765,11 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) err = -EINVAL; goto out; } + /* no need to apply CO-RE relocation if the program is + * not going to be loaded + */ + if (!prog->load) + continue; err = bpf_core_apply_relo(prog, rec, i, obj->btf, targ_btf, cand_cache); -- cgit v1.2.3 From a66345bcbdf0c5070479c26103f7cb33da9e4969 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 7 Oct 2020 17:10:22 -0700 Subject: libbpf: Support safe subset of load/store instruction resizing with CO-RE Add support for patching instructions of the following form: - rX = *(T *)(rY + ); - *(T *)(rX + ) = rY; - *(T *)(rX + ) = , where T is one of {u8, u16, u32, u64}. For such instructions, if the actual kernel field recorded in CO-RE relocation has a different size than the one recorded locally (e.g., from vmlinux.h), then libbpf will adjust T to an appropriate 1-, 2-, 4-, or 8-byte loads. In general, such transformation is not always correct and could lead to invalid final value being loaded or stored. But two classes of cases are always safe: - if both local and target (kernel) types are unsigned integers, but of different sizes, then it's OK to adjust load/store instruction according to the necessary memory size. Zero-extending nature of such instructions and unsignedness make sure that the final value is always correct; - pointer size mismatch between BPF target architecture (which is always 64-bit) and 32-bit host kernel architecture can be similarly resolved automatically, because pointer is essentially an unsigned integer. Loading 32-bit pointer into 64-bit BPF register with zero extension will leave correct pointer in the register. Both cases are necessary to support CO-RE on 32-bit kernels, as `unsigned long` in vmlinux.h generated from 32-bit kernel is 32-bit, but when compiled with BPF program for BPF target it will be treated by compiler as 64-bit integer. Similarly, pointers in vmlinux.h are 32-bit for kernel, but treated as 64-bit values by compiler for BPF target. Both problems are now resolved by libbpf for direct memory reads. But similar transformations are useful in general when kernel fields are "resized" from, e.g., unsigned int to unsigned long (or vice versa). Now, similar transformations for signed integers are not safe to perform as they will result in incorrect sign extension of the value. If such situation is detected, libbpf will emit helpful message and will poison the instruction. Not failing immediately means that it's possible to guard the instruction based on kernel version (or other conditions) and make sure it's not reachable. If there is a need to read signed integers that change sizes between different kernels, it's possible to use BPF_CORE_READ_BITFIELD() macro, which works both with bitfields and non-bitfield integers of any signedness and handles sign-extension properly. Also, bpf_core_read() with proper size and/or use of bpf_core_field_size() relocation could allow to deal with such complicated situations explicitly, if not so conventiently as direct memory reads. Selftests added in a separate patch in progs/test_core_autosize.c demonstrate both direct memory and probed use cases. BPF_CORE_READ() is not changed and it won't deal with such situations as automatically as direct memory reads due to the signedness integer limitations, which are much harder to detect and control with compiler macro magic. So it's encouraged to utilize direct memory reads as much as possible. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20201008001025.292064-3-andrii@kernel.org --- tools/lib/bpf/libbpf.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 136 insertions(+), 8 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 07d62771472f..032cf0049ddb 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5040,16 +5040,19 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec, static int bpf_core_calc_field_relo(const struct bpf_program *prog, const struct bpf_core_relo *relo, const struct bpf_core_spec *spec, - __u32 *val, bool *validate) + __u32 *val, __u32 *field_sz, __u32 *type_id, + bool *validate) { const struct bpf_core_accessor *acc; const struct btf_type *t; - __u32 byte_off, byte_sz, bit_off, bit_sz; + __u32 byte_off, byte_sz, bit_off, bit_sz, field_type_id; const struct btf_member *m; const struct btf_type *mt; bool bitfield; __s64 sz; + *field_sz = 0; + if (relo->kind == BPF_FIELD_EXISTS) { *val = spec ? 1 : 0; return 0; @@ -5065,6 +5068,12 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, if (!acc->name) { if (relo->kind == BPF_FIELD_BYTE_OFFSET) { *val = spec->bit_offset / 8; + /* remember field size for load/store mem size */ + sz = btf__resolve_size(spec->btf, acc->type_id); + if (sz < 0) + return -EINVAL; + *field_sz = sz; + *type_id = acc->type_id; } else if (relo->kind == BPF_FIELD_BYTE_SIZE) { sz = btf__resolve_size(spec->btf, acc->type_id); if (sz < 0) @@ -5081,7 +5090,7 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, } m = btf_members(t) + acc->idx; - mt = skip_mods_and_typedefs(spec->btf, m->type, NULL); + mt = skip_mods_and_typedefs(spec->btf, m->type, &field_type_id); bit_off = spec->bit_offset; bit_sz = btf_member_bitfield_size(t, acc->idx); @@ -5101,7 +5110,7 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, byte_off = bit_off / 8 / byte_sz * byte_sz; } } else { - sz = btf__resolve_size(spec->btf, m->type); + sz = btf__resolve_size(spec->btf, field_type_id); if (sz < 0) return -EINVAL; byte_sz = sz; @@ -5119,6 +5128,10 @@ static int bpf_core_calc_field_relo(const struct bpf_program *prog, switch (relo->kind) { case BPF_FIELD_BYTE_OFFSET: *val = byte_off; + if (!bitfield) { + *field_sz = byte_sz; + *type_id = field_type_id; + } break; case BPF_FIELD_BYTE_SIZE: *val = byte_sz; @@ -5219,6 +5232,19 @@ struct bpf_core_relo_res bool poison; /* some relocations can't be validated against orig_val */ bool validate; + /* for field byte offset relocations or the forms: + * *(T *)(rX + ) = rY + * rX = *(T *)(rY + ), + * we remember original and resolved field size to adjust direct + * memory loads of pointers and integers; this is necessary for 32-bit + * host kernel architectures, but also allows to automatically + * relocate fields that were resized from, e.g., u32 to u64, etc. + */ + bool fail_memsz_adjust; + __u32 orig_sz; + __u32 orig_type_id; + __u32 new_sz; + __u32 new_type_id; }; /* Calculate original and target relocation values, given local and target @@ -5240,10 +5266,56 @@ static int bpf_core_calc_relo(const struct bpf_program *prog, res->new_val = 0; res->poison = false; res->validate = true; + res->fail_memsz_adjust = false; + res->orig_sz = res->new_sz = 0; + res->orig_type_id = res->new_type_id = 0; if (core_relo_is_field_based(relo->kind)) { - err = bpf_core_calc_field_relo(prog, relo, local_spec, &res->orig_val, &res->validate); - err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec, &res->new_val, NULL); + err = bpf_core_calc_field_relo(prog, relo, local_spec, + &res->orig_val, &res->orig_sz, + &res->orig_type_id, &res->validate); + err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec, + &res->new_val, &res->new_sz, + &res->new_type_id, NULL); + if (err) + goto done; + /* Validate if it's safe to adjust load/store memory size. + * Adjustments are performed only if original and new memory + * sizes differ. + */ + res->fail_memsz_adjust = false; + if (res->orig_sz != res->new_sz) { + const struct btf_type *orig_t, *new_t; + + orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id); + new_t = btf__type_by_id(targ_spec->btf, res->new_type_id); + + /* There are two use cases in which it's safe to + * adjust load/store's mem size: + * - reading a 32-bit kernel pointer, while on BPF + * size pointers are always 64-bit; in this case + * it's safe to "downsize" instruction size due to + * pointer being treated as unsigned integer with + * zero-extended upper 32-bits; + * - reading unsigned integers, again due to + * zero-extension is preserving the value correctly. + * + * In all other cases it's incorrect to attempt to + * load/store field because read value will be + * incorrect, so we poison relocated instruction. + */ + if (btf_is_ptr(orig_t) && btf_is_ptr(new_t)) + goto done; + if (btf_is_int(orig_t) && btf_is_int(new_t) && + btf_int_encoding(orig_t) != BTF_INT_SIGNED && + btf_int_encoding(new_t) != BTF_INT_SIGNED) + goto done; + + /* mark as invalid mem size adjustment, but this will + * only be checked for LDX/STX/ST insns + */ + res->fail_memsz_adjust = true; + } } else if (core_relo_is_type_based(relo->kind)) { err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val); err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val); @@ -5252,6 +5324,7 @@ static int bpf_core_calc_relo(const struct bpf_program *prog, err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val); } +done: if (err == -EUCLEAN) { /* EUCLEAN is used to signal instruction poisoning request */ res->poison = true; @@ -5291,6 +5364,28 @@ static bool is_ldimm64(struct bpf_insn *insn) return insn->code == (BPF_LD | BPF_IMM | BPF_DW); } +static int insn_bpf_size_to_bytes(struct bpf_insn *insn) +{ + switch (BPF_SIZE(insn->code)) { + case BPF_DW: return 8; + case BPF_W: return 4; + case BPF_H: return 2; + case BPF_B: return 1; + default: return -1; + } +} + +static int insn_bytes_to_bpf_size(__u32 sz) +{ + switch (sz) { + case 8: return BPF_DW; + case 4: return BPF_W; + case 2: return BPF_H; + case 1: return BPF_B; + default: return -1; + } +} + /* * Patch relocatable BPF instruction. * @@ -5300,10 +5395,13 @@ static bool is_ldimm64(struct bpf_insn *insn) * spec, and is checked before patching instruction. If actual insn->imm value * is wrong, bail out with error. * - * Currently three kinds of BPF instructions are supported: + * Currently supported classes of BPF instruction are: * 1. rX = (assignment with immediate operand); * 2. rX += (arithmetic operations with immediate operand); - * 3. rX = (load with 64-bit immediate value). + * 3. rX = (load with 64-bit immediate value); + * 4. rX = *(T *)(rY + ), where T is one of {u8, u16, u32, u64}; + * 5. *(T *)(rX + ) = rY, where T is one of {u8, u16, u32, u64}; + * 6. *(T *)(rX + ) = , where T is one of {u8, u16, u32, u64}. */ static int bpf_core_patch_insn(struct bpf_program *prog, const struct bpf_core_relo *relo, @@ -5327,6 +5425,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog, class = BPF_CLASS(insn->code); if (res->poison) { +poison: /* poison second part of ldimm64 to avoid confusing error from * verifier about "unknown opcode 00" */ @@ -5369,10 +5468,39 @@ static int bpf_core_patch_insn(struct bpf_program *prog, prog->name, relo_idx, insn_idx, new_val); return -ERANGE; } + if (res->fail_memsz_adjust) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) accesses field incorrectly. " + "Make sure you are accessing pointers, unsigned integers, or fields of matching type and size.\n", + prog->name, relo_idx, insn_idx); + goto poison; + } + orig_val = insn->off; insn->off = new_val; pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n", prog->name, relo_idx, insn_idx, orig_val, new_val); + + if (res->new_sz != res->orig_sz) { + int insn_bytes_sz, insn_bpf_sz; + + insn_bytes_sz = insn_bpf_size_to_bytes(insn); + if (insn_bytes_sz != res->orig_sz) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) unexpected mem size: got %d, exp %u\n", + prog->name, relo_idx, insn_idx, insn_bytes_sz, res->orig_sz); + return -EINVAL; + } + + insn_bpf_sz = insn_bytes_to_bpf_size(res->new_sz); + if (insn_bpf_sz < 0) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) invalid new mem size: %u\n", + prog->name, relo_idx, insn_idx, res->new_sz); + return -EINVAL; + } + + insn->code = BPF_MODE(insn->code) | insn_bpf_sz | BPF_CLASS(insn->code); + pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) mem_sz %u -> %u\n", + prog->name, relo_idx, insn_idx, res->orig_sz, res->new_sz); + } break; case BPF_LD: { __u64 imm; -- cgit v1.2.3 From 2b7d88c2b582c659a6567e851d96873d0209a501 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 7 Oct 2020 17:10:23 -0700 Subject: libbpf: Allow specifying both ELF and raw BTF for CO-RE BTF override Use generalized BTF parsing logic, making it possible to parse BTF both from ELF file, as well as a raw BTF dump. This makes it easier to write custom tests with manually generated BTFs. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20201008001025.292064-4-andrii@kernel.org --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 032cf0049ddb..105cb8ad1d75 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5842,7 +5842,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) return 0; if (targ_btf_path) - targ_btf = btf__parse_elf(targ_btf_path, NULL); + targ_btf = btf__parse(targ_btf_path, NULL); else targ_btf = obj->btf_vmlinux; if (IS_ERR_OR_NULL(targ_btf)) { -- cgit v1.2.3