diff options
| -rw-r--r-- | tools/bpf/resolve_btfids/main.c | 8 | ||||
| -rw-r--r-- | tools/lib/bpf/Build | 2 | ||||
| -rw-r--r-- | tools/lib/bpf/btf.c | 498 | ||||
| -rw-r--r-- | tools/lib/bpf/btf.h | 36 | ||||
| -rw-r--r-- | tools/lib/bpf/btf_relocate.c | 506 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.map | 2 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf_internal.h | 3 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/btf_distill.c | 552 |
8 files changed, 1547 insertions, 60 deletions
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c index af393c7dee1f..936ef95c3d32 100644 --- a/tools/bpf/resolve_btfids/main.c +++ b/tools/bpf/resolve_btfids/main.c @@ -409,6 +409,14 @@ static int elf_collect(struct object *obj) obj->efile.idlist = data; obj->efile.idlist_shndx = idx; obj->efile.idlist_addr = sh.sh_addr; + } else if (!strcmp(name, BTF_BASE_ELF_SEC)) { + /* If a .BTF.base section is found, do not resolve + * BTF ids relative to vmlinux; resolve relative + * to the .BTF.base section instead. btf__parse_split() + * will take care of this once the base BTF it is + * passed is NULL. + */ + obj->base_btf_path = NULL; } if (compressed_section_fix(elf, scn, &sh)) diff --git a/tools/lib/bpf/Build b/tools/lib/bpf/Build index b6619199a706..336da6844d42 100644 --- a/tools/lib/bpf/Build +++ b/tools/lib/bpf/Build @@ -1,4 +1,4 @@ libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \ netlink.o bpf_prog_linfo.o libbpf_probes.o hashmap.o \ btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o \ - usdt.o zip.o elf.o features.o + usdt.o zip.o elf.o features.o btf_relocate.o diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 775ca55a541c..ef1b2f573c1b 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -116,6 +116,9 @@ struct btf { /* whether strings are already deduplicated */ bool strs_deduped; + /* whether base_btf should be freed in btf_free for this instance */ + bool owns_base; + /* BTF object FD, if loaded into kernel */ int fd; @@ -969,6 +972,8 @@ void btf__free(struct btf *btf) free(btf->raw_data); free(btf->raw_data_swapped); free(btf->type_offs); + if (btf->owns_base) + btf__free(btf->base_btf); free(btf); } @@ -1084,53 +1089,38 @@ struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) return libbpf_ptr(btf_new(data, size, base_btf)); } -static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, - struct btf_ext **btf_ext) +struct btf_elf_secs { + Elf_Data *btf_data; + Elf_Data *btf_ext_data; + Elf_Data *btf_base_data; +}; + +static int btf_find_elf_sections(Elf *elf, const char *path, struct btf_elf_secs *secs) { - Elf_Data *btf_data = NULL, *btf_ext_data = NULL; - int err = 0, fd = -1, idx = 0; - struct btf *btf = NULL; Elf_Scn *scn = NULL; - Elf *elf = NULL; + Elf_Data *data; GElf_Ehdr ehdr; size_t shstrndx; + int idx = 0; - if (elf_version(EV_CURRENT) == EV_NONE) { - pr_warn("failed to init libelf for %s\n", path); - return ERR_PTR(-LIBBPF_ERRNO__LIBELF); - } - - fd = open(path, O_RDONLY | O_CLOEXEC); - if (fd < 0) { - err = -errno; - pr_warn("failed to open %s: %s\n", path, strerror(errno)); - return ERR_PTR(err); - } - - err = -LIBBPF_ERRNO__FORMAT; - - elf = elf_begin(fd, ELF_C_READ, NULL); - if (!elf) { - pr_warn("failed to open %s as ELF file\n", path); - goto done; - } if (!gelf_getehdr(elf, &ehdr)) { pr_warn("failed to get EHDR from %s\n", path); - goto done; + goto err; } if (elf_getshdrstrndx(elf, &shstrndx)) { pr_warn("failed to get section names section index for %s\n", path); - goto done; + goto err; } if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); - goto done; + goto err; } while ((scn = elf_nextscn(elf, scn)) != NULL) { + Elf_Data **field; GElf_Shdr sh; char *name; @@ -1138,42 +1128,102 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, if (gelf_getshdr(scn, &sh) != &sh) { pr_warn("failed to get section(%d) header from %s\n", idx, path); - goto done; + goto err; } name = elf_strptr(elf, shstrndx, sh.sh_name); if (!name) { pr_warn("failed to get section(%d) name from %s\n", idx, path); - goto done; + goto err; } - if (strcmp(name, BTF_ELF_SEC) == 0) { - btf_data = elf_getdata(scn, 0); - if (!btf_data) { - pr_warn("failed to get section(%d, %s) data from %s\n", - idx, name, path); - goto done; - } - continue; - } else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) { - btf_ext_data = elf_getdata(scn, 0); - if (!btf_ext_data) { - pr_warn("failed to get section(%d, %s) data from %s\n", - idx, name, path); - goto done; - } + + if (strcmp(name, BTF_ELF_SEC) == 0) + field = &secs->btf_data; + else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) + field = &secs->btf_ext_data; + else if (strcmp(name, BTF_BASE_ELF_SEC) == 0) + field = &secs->btf_base_data; + else continue; + + data = elf_getdata(scn, 0); + if (!data) { + pr_warn("failed to get section(%d, %s) data from %s\n", + idx, name, path); + goto err; } + *field = data; + } + + return 0; + +err: + return -LIBBPF_ERRNO__FORMAT; +} + +static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, + struct btf_ext **btf_ext) +{ + struct btf_elf_secs secs = {}; + struct btf *dist_base_btf = NULL; + struct btf *btf = NULL; + int err = 0, fd = -1; + Elf *elf = NULL; + + if (elf_version(EV_CURRENT) == EV_NONE) { + pr_warn("failed to init libelf for %s\n", path); + return ERR_PTR(-LIBBPF_ERRNO__LIBELF); + } + + fd = open(path, O_RDONLY | O_CLOEXEC); + if (fd < 0) { + err = -errno; + pr_warn("failed to open %s: %s\n", path, strerror(errno)); + return ERR_PTR(err); + } + + elf = elf_begin(fd, ELF_C_READ, NULL); + if (!elf) { + pr_warn("failed to open %s as ELF file\n", path); + goto done; } - if (!btf_data) { + err = btf_find_elf_sections(elf, path, &secs); + if (err) + goto done; + + if (!secs.btf_data) { pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); err = -ENODATA; goto done; } - btf = btf_new(btf_data->d_buf, btf_data->d_size, base_btf); - err = libbpf_get_error(btf); - if (err) + + if (secs.btf_base_data) { + dist_base_btf = btf_new(secs.btf_base_data->d_buf, secs.btf_base_data->d_size, + NULL); + if (IS_ERR(dist_base_btf)) { + err = PTR_ERR(dist_base_btf); + dist_base_btf = NULL; + goto done; + } + } + + btf = btf_new(secs.btf_data->d_buf, secs.btf_data->d_size, + dist_base_btf ?: base_btf); + if (IS_ERR(btf)) { + err = PTR_ERR(btf); goto done; + } + if (dist_base_btf && base_btf) { + err = btf__relocate(btf, base_btf); + if (err) + goto done; + btf__free(dist_base_btf); + dist_base_btf = NULL; + } + + if (dist_base_btf) + btf->owns_base = true; switch (gelf_getclass(elf)) { case ELFCLASS32: @@ -1187,11 +1237,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, break; } - if (btf_ext && btf_ext_data) { - *btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size); - err = libbpf_get_error(*btf_ext); - if (err) + if (btf_ext && secs.btf_ext_data) { + *btf_ext = btf_ext__new(secs.btf_ext_data->d_buf, secs.btf_ext_data->d_size); + if (IS_ERR(*btf_ext)) { + err = PTR_ERR(*btf_ext); goto done; + } } else if (btf_ext) { *btf_ext = NULL; } @@ -1205,6 +1256,7 @@ done: if (btf_ext) btf_ext__free(*btf_ext); + btf__free(dist_base_btf); btf__free(btf); return ERR_PTR(err); @@ -1770,9 +1822,8 @@ static int btf_rewrite_str(struct btf_pipe *p, __u32 *str_off) return 0; } -int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) +static int btf_add_type(struct btf_pipe *p, const struct btf_type *src_type) { - struct btf_pipe p = { .src = src_btf, .dst = btf }; struct btf_field_iter it; struct btf_type *t; __u32 *str_off; @@ -1783,10 +1834,10 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t return libbpf_err(sz); /* deconstruct BTF, if necessary, and invalidate raw_data */ - if (btf_ensure_modifiable(btf)) + if (btf_ensure_modifiable(p->dst)) return libbpf_err(-ENOMEM); - t = btf_add_type_mem(btf, sz); + t = btf_add_type_mem(p->dst, sz); if (!t) return libbpf_err(-ENOMEM); @@ -1797,12 +1848,19 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t return libbpf_err(err); while ((str_off = btf_field_iter_next(&it))) { - err = btf_rewrite_str(&p, str_off); + err = btf_rewrite_str(p, str_off); if (err) return libbpf_err(err); } - return btf_commit_type(btf, sz); + return btf_commit_type(p->dst, sz); +} + +int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) +{ + struct btf_pipe p = { .src = src_btf, .dst = btf }; + + return btf_add_type(&p, src_type); } static size_t btf_dedup_identity_hash_fn(long key, void *ctx); @@ -5276,3 +5334,325 @@ int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void return 0; } + +struct btf_distill { + struct btf_pipe pipe; + int *id_map; + unsigned int split_start_id; + unsigned int split_start_str; + int diff_id; +}; + +static int btf_add_distilled_type_ids(struct btf_distill *dist, __u32 i) +{ + struct btf_type *split_t = btf_type_by_id(dist->pipe.src, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, split_t, BTF_FIELD_ITER_IDS); + if (err) + return err; + while ((id = btf_field_iter_next(&it))) { + struct btf_type *base_t; + + if (!*id) + continue; + /* split BTF id, not needed */ + if (*id >= dist->split_start_id) + continue; + /* already added ? */ + if (dist->id_map[*id] > 0) + continue; + + /* only a subset of base BTF types should be referenced from + * split BTF; ensure nothing unexpected is referenced. + */ + base_t = btf_type_by_id(dist->pipe.src, *id); + switch (btf_kind(base_t)) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + case BTF_KIND_ARRAY: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_TYPEDEF: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TYPE_TAG: + dist->id_map[*id] = *id; + break; + default: + pr_warn("unexpected reference to base type[%u] of kind [%u] when creating distilled base BTF.\n", + *id, btf_kind(base_t)); + return -EINVAL; + } + /* If a base type is used, ensure types it refers to are + * marked as used also; so for example if we find a PTR to INT + * we need both the PTR and INT. + * + * The only exception is named struct/unions, since distilled + * base BTF composite types have no members. + */ + if (btf_is_composite(base_t) && base_t->name_off) + continue; + err = btf_add_distilled_type_ids(dist, *id); + if (err) + return err; + } + return 0; +} + +static int btf_add_distilled_types(struct btf_distill *dist) +{ + bool adding_to_base = dist->pipe.dst->start_id == 1; + int id = btf__type_cnt(dist->pipe.dst); + struct btf_type *t; + int i, err = 0; + + + /* Add types for each of the required references to either distilled + * base or split BTF, depending on type characteristics. + */ + for (i = 1; i < dist->split_start_id; i++) { + const char *name; + int kind; + + if (!dist->id_map[i]) + continue; + t = btf_type_by_id(dist->pipe.src, i); + kind = btf_kind(t); + name = btf__name_by_offset(dist->pipe.src, t->name_off); + + switch (kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + /* Named int, float, fwd are added to base. */ + if (!adding_to_base) + continue; + err = btf_add_type(&dist->pipe, t); + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* Named struct/union are added to base as 0-vlen + * struct/union of same size. Anonymous struct/unions + * are added to split BTF as-is. + */ + if (adding_to_base) { + if (!t->name_off) + continue; + err = btf_add_composite(dist->pipe.dst, kind, name, t->size); + } else { + if (t->name_off) + continue; + err = btf_add_type(&dist->pipe, t); + } + break; + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + /* Named enum[64]s are added to base as a sized + * enum; relocation will match with appropriately-named + * and sized enum or enum64. + * + * Anonymous enums are added to split BTF as-is. + */ + if (adding_to_base) { + if (!t->name_off) + continue; + err = btf__add_enum(dist->pipe.dst, name, t->size); + } else { + if (t->name_off) + continue; + err = btf_add_type(&dist->pipe, t); + } + break; + case BTF_KIND_ARRAY: + case BTF_KIND_TYPEDEF: + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TYPE_TAG: + /* All other types are added to split BTF. */ + if (adding_to_base) + continue; + err = btf_add_type(&dist->pipe, t); + break; + default: + pr_warn("unexpected kind when adding base type '%s'[%u] of kind [%u] to distilled base BTF.\n", + name, i, kind); + return -EINVAL; + + } + if (err < 0) + break; + dist->id_map[i] = id++; + } + return err; +} + +/* Split BTF ids without a mapping will be shifted downwards since distilled + * base BTF is smaller than the original base BTF. For those that have a + * mapping (either to base or updated split BTF), update the id based on + * that mapping. + */ +static int btf_update_distilled_type_ids(struct btf_distill *dist, __u32 i) +{ + struct btf_type *t = btf_type_by_id(dist->pipe.dst, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + while ((id = btf_field_iter_next(&it))) { + if (dist->id_map[*id]) + *id = dist->id_map[*id]; + else if (*id >= dist->split_start_id) + *id -= dist->diff_id; + } + return 0; +} + +/* Create updated split BTF with distilled base BTF; distilled base BTF + * consists of BTF information required to clarify the types that split + * BTF refers to, omitting unneeded details. Specifically it will contain + * base types and memberless definitions of named structs, unions and enumerated + * types. Associated reference types like pointers, arrays and anonymous + * structs, unions and enumerated types will be added to split BTF. + * Size is recorded for named struct/unions to help guide matching to the + * target base BTF during later relocation. + * + * The only case where structs, unions or enumerated types are fully represented + * is when they are anonymous; in such cases, the anonymous type is added to + * split BTF in full. + * + * We return newly-created split BTF where the split BTF refers to a newly-created + * distilled base BTF. Both must be freed separately by the caller. + */ +int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf, + struct btf **new_split_btf) +{ + struct btf *new_base = NULL, *new_split = NULL; + const struct btf *old_base; + unsigned int n = btf__type_cnt(src_btf); + struct btf_distill dist = {}; + struct btf_type *t; + int i, err = 0; + + /* src BTF must be split BTF. */ + old_base = btf__base_btf(src_btf); + if (!new_base_btf || !new_split_btf || !old_base) + return libbpf_err(-EINVAL); + + new_base = btf__new_empty(); + if (!new_base) + return libbpf_err(-ENOMEM); + dist.id_map = calloc(n, sizeof(*dist.id_map)); + if (!dist.id_map) { + err = -ENOMEM; + goto done; + } + dist.pipe.src = src_btf; + dist.pipe.dst = new_base; + dist.pipe.str_off_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL); + if (IS_ERR(dist.pipe.str_off_map)) { + err = -ENOMEM; + goto done; + } + dist.split_start_id = btf__type_cnt(old_base); + dist.split_start_str = old_base->hdr->str_len; + + /* Pass over src split BTF; generate the list of base BTF type ids it + * references; these will constitute our distilled BTF set to be + * distributed over base and split BTF as appropriate. + */ + for (i = src_btf->start_id; i < n; i++) { + err = btf_add_distilled_type_ids(&dist, i); + if (err < 0) + goto done; + } + /* Next add types for each of the required references to base BTF and split BTF + * in turn. + */ + err = btf_add_distilled_types(&dist); + if (err < 0) + goto done; + + /* Create new split BTF with distilled base BTF as its base; the final + * state is split BTF with distilled base BTF that represents enough + * about its base references to allow it to be relocated with the base + * BTF available. + */ + new_split = btf__new_empty_split(new_base); + if (!new_split_btf) { + err = -errno; + goto done; + } + dist.pipe.dst = new_split; + /* First add all split types */ + for (i = src_btf->start_id; i < n; i++) { + t = btf_type_by_id(src_btf, i); + err = btf_add_type(&dist.pipe, t); + if (err < 0) + goto done; + } + /* Now add distilled types to split BTF that are not added to base. */ + err = btf_add_distilled_types(&dist); + if (err < 0) + goto done; + + /* All split BTF ids will be shifted downwards since there are less base + * BTF ids in distilled base BTF. + */ + dist.diff_id = dist.split_start_id - btf__type_cnt(new_base); + + n = btf__type_cnt(new_split); + /* Now update base/split BTF ids. */ + for (i = 1; i < n; i++) { + err = btf_update_distilled_type_ids(&dist, i); + if (err < 0) + break; + } +done: + free(dist.id_map); + hashmap__free(dist.pipe.str_off_map); + if (err) { + btf__free(new_split); + btf__free(new_base); + return libbpf_err(err); + } + *new_base_btf = new_base; + *new_split_btf = new_split; + + return 0; +} + +const struct btf_header *btf_header(const struct btf *btf) +{ + return btf->hdr; +} + +void btf_set_base_btf(struct btf *btf, const struct btf *base_btf) +{ + btf->base_btf = (struct btf *)base_btf; + btf->start_id = btf__type_cnt(base_btf); + btf->start_str_off = base_btf->hdr->str_len; +} + +int btf__relocate(struct btf *btf, const struct btf *base_btf) +{ + int err = btf_relocate(btf, base_btf, NULL); + + if (!err) + btf->owns_base = false; + return libbpf_err(err); +} diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 8e6880d91c84..b68d216837a9 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -18,6 +18,7 @@ extern "C" { #define BTF_ELF_SEC ".BTF" #define BTF_EXT_ELF_SEC ".BTF.ext" +#define BTF_BASE_ELF_SEC ".BTF.base" #define MAPS_ELF_SEC ".maps" struct btf; @@ -107,6 +108,27 @@ LIBBPF_API struct btf *btf__new_empty(void); */ LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf); +/** + * @brief **btf__distill_base()** creates new versions of the split BTF + * *src_btf* and its base BTF. The new base BTF will only contain the types + * needed to improve robustness of the split BTF to small changes in base BTF. + * When that split BTF is loaded against a (possibly changed) base, this + * distilled base BTF will help update references to that (possibly changed) + * base BTF. + * + * Both the new split and its associated new base BTF must be freed by + * the caller. + * + * If successful, 0 is returned and **new_base_btf** and **new_split_btf** + * will point at new base/split BTF. Both the new split and its associated + * new base BTF must be freed by the caller. + * + * A negative value is returned on error and the thread-local `errno` variable + * is set to the error code as well. + */ +LIBBPF_API int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf, + struct btf **new_split_btf); + LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext); LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf); LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext); @@ -231,6 +253,20 @@ struct btf_dedup_opts { LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts); +/** + * @brief **btf__relocate()** will check the split BTF *btf* for references + * to base BTF kinds, and verify those references are compatible with + * *base_btf*; if they are, *btf* is adjusted such that is re-parented to + * *base_btf* and type ids and strings are adjusted to accommodate this. + * + * If successful, 0 is returned and **btf** now has **base_btf** as its + * base. + * + * A negative value is returned on error and the thread-local `errno` variable + * is set to the error code as well. + */ +LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf); + struct btf_dump; struct btf_dump_opts { diff --git a/tools/lib/bpf/btf_relocate.c b/tools/lib/bpf/btf_relocate.c new file mode 100644 index 000000000000..eabb8755f662 --- /dev/null +++ b/tools/lib/bpf/btf_relocate.c @@ -0,0 +1,506 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024, Oracle and/or its affiliates. */ + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif + +#include "btf.h" +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" + +struct btf; + +struct btf_relocate { + struct btf *btf; + const struct btf *base_btf; + const struct btf *dist_base_btf; + unsigned int nr_base_types; + unsigned int nr_split_types; + unsigned int nr_dist_base_types; + int dist_str_len; + int base_str_len; + __u32 *id_map; + __u32 *str_map; +}; + +/* Set temporarily in relocation id_map if distilled base struct/union is + * embedded in a split BTF struct/union; in such a case, size information must + * match between distilled base BTF and base BTF representation of type. + */ +#define BTF_IS_EMBEDDED ((__u32)-1) + +/* <name, size, id> triple used in sorting/searching distilled base BTF. */ +struct btf_name_info { + const char *name; + /* set when search requires a size match */ + int needs_size:1, + size:31; + __u32 id; +}; + +static int btf_relocate_rewrite_type_id(struct btf_relocate *r, __u32 i) +{ + struct btf_type *t = btf_type_by_id(r->btf, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + + while ((id = btf_field_iter_next(&it))) + *id = r->id_map[*id]; + return 0; +} + +/* Simple string comparison used for sorting within BTF, since all distilled + * types are named. If strings match, and size is non-zero for both elements + * fall back to using size for ordering. + */ +static int cmp_btf_name_size(const void *n1, const void *n2) +{ + const struct btf_name_info *ni1 = n1; + const struct btf_name_info *ni2 = n2; + int name_diff = strcmp(ni1->name, ni2->name); + + if (!name_diff && ni1->needs_size && ni2->needs_size) + return ni2->size - ni1->size; + return name_diff; +} + +/* Binary search with a small twist; find leftmost element that matches + * so that we can then iterate through all exact matches. So for example + * searching { "a", "bb", "bb", "c" } we would always match on the + * leftmost "bb". + */ +static struct btf_name_info *search_btf_name_size(struct btf_name_info *key, + struct btf_name_info *vals, + int nelems) +{ + struct btf_name_info *ret = NULL; + int high = nelems - 1; + int low = 0; + + while (low <= high) { + int mid = (low + high)/2; + struct btf_name_info *val = &vals[mid]; + int diff = cmp_btf_name_size(key, val); + + if (diff == 0) + ret = val; + /* even if found, keep searching for leftmost match */ + if (diff <= 0) + high = mid - 1; + else + low = mid + 1; + } + return ret; +} + +/* If a member of a split BTF struct/union refers to a base BTF + * struct/union, mark that struct/union id temporarily in the id_map + * with BTF_IS_EMBEDDED. Members can be const/restrict/volatile/typedef + * reference types, but if a pointer is encountered, the type is no longer + * considered embedded. + */ +static int btf_mark_embedded_composite_type_ids(struct btf_relocate *r, __u32 i) +{ + struct btf_type *t = btf_type_by_id(r->btf, i); + struct btf_field_iter it; + __u32 *id; + int err; + + if (!btf_is_composite(t)) + return 0; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + + while ((id = btf_field_iter_next(&it))) { + __u32 next_id = *id; + + while (next_id) { + t = btf_type_by_id(r->btf, next_id); + switch (btf_kind(t)) { + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_TYPEDEF: + case BTF_KIND_TYPE_TAG: + next_id = t->type; + break; + case BTF_KIND_ARRAY: { + struct btf_array *a = btf_array(t); + + next_id = a->type; + break; + } + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + if (next_id < r->nr_dist_base_types) + r->id_map[next_id] = BTF_IS_EMBEDDED; + next_id = 0; + break; + default: + next_id = 0; + break; + } + } + } + + return 0; +} + +/* Build a map from distilled base BTF ids to base BTF ids. To do so, iterate + * through base BTF looking up distilled type (using binary search) equivalents. + */ +static int btf_relocate_map_distilled_base(struct btf_relocate *r) +{ + struct btf_name_info *dist_base_info_sorted, *dist_base_info_sorted_end; + struct btf_type *base_t, *dist_t; + __u8 *base_name_cnt = NULL; + int err = 0; + __u32 id; + + /* generate a sort index array of name/type ids sorted by name for + * distilled base BTF to speed name-based lookups. + */ + dist_base_info_sorted = calloc(r->nr_dist_base_types, sizeof(*dist_base_info_sorted)); + if (!dist_base_info_sorted) { + err = -ENOMEM; + goto done; + } + dist_base_info_sorted_end = dist_base_info_sorted + r->nr_dist_base_types; + for (id = 0; id < r->nr_dist_base_types; id++) { + dist_t = btf_type_by_id(r->dist_base_btf, id); + dist_base_info_sorted[id].name = btf__name_by_offset(r->dist_base_btf, + dist_t->name_off); + dist_base_info_sorted[id].id = id; + dist_base_info_sorted[id].size = dist_t->size; + dist_base_info_sorted[id].needs_size = true; + } + qsort(dist_base_info_sorted, r->nr_dist_base_types, sizeof(*dist_base_info_sorted), + cmp_btf_name_size); + + /* Mark distilled base struct/union members of split BTF structs/unions + * in id_map with BTF_IS_EMBEDDED; this signals that these types + * need to match both name and size, otherwise embeddding the base + * struct/union in the split type is invalid. + */ + for (id = r->nr_dist_base_types; id < r->nr_split_types; id++) { + err = btf_mark_embedded_composite_type_ids(r, id); + if (err) + goto done; + } + + /* Collect name counts for composite types in base BTF. If multiple + * instances of a struct/union of the same name exist, we need to use + * size to determine which to map to since name alone is ambiguous. + */ + base_name_cnt = calloc(r->base_str_len, sizeof(*base_name_cnt)); + if (!base_name_cnt) { + err = -ENOMEM; + goto done; + } + for (id = 1; id < r->nr_base_types; id++) { + base_t = btf_type_by_id(r->base_btf, id); + if (!btf_is_composite(base_t) || !base_t->name_off) + continue; + if (base_name_cnt[base_t->name_off] < 255) + base_name_cnt[base_t->name_off]++; + } + + /* Now search base BTF for matching distilled base BTF types. */ + for (id = 1; id < r->nr_base_types; id++) { + struct btf_name_info *dist_name_info, *dist_name_info_next = NULL; + struct btf_name_info base_name_info = {}; + int dist_kind, base_kind; + + base_t = btf_type_by_id(r->base_btf, id); + /* distilled base consists of named types only. */ + if (!base_t->name_off) + continue; + base_kind = btf_kind(base_t); + base_name_info.id = id; + base_name_info.name = btf__name_by_offset(r->base_btf, base_t->name_off); + switch (base_kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + /* These types should match both name and size */ + base_name_info.needs_size = true; + base_name_info.size = base_t->size; + break; + case BTF_KIND_FWD: + /* No size considerations for fwds. */ + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* Size only needs to be used for struct/union if there + * are multiple types in base BTF with the same name. + * If there are multiple _distilled_ types with the same + * name (a very unlikely scenario), that doesn't matter + * unless corresponding _base_ types to match them are + * missing. + */ + base_name_info.needs_size = base_name_cnt[base_t->name_off] > 1; + base_name_info.size = base_t->size; + break; + default: + continue; + } + /* iterate over all matching distilled base types */ + for (dist_name_info = search_btf_name_size(&base_name_info, dist_base_info_sorted, + r->nr_dist_base_types); + dist_name_info != NULL; dist_name_info = dist_name_info_next) { + /* Are there more distilled matches to process after + * this one? + */ + dist_name_info_next = dist_name_info + 1; + if (dist_name_info_next >= dist_base_info_sorted_end || + cmp_btf_name_size(&base_name_info, dist_name_info_next)) + dist_name_info_next = NULL; + + if (!dist_name_info->id || dist_name_info->id > r->nr_dist_base_types) { + pr_warn("base BTF id [%d] maps to invalid distilled base BTF id [%d]\n", + id, dist_name_info->id); + err = -EINVAL; + goto done; + } + dist_t = btf_type_by_id(r->dist_base_btf, dist_name_info->id); + dist_kind = btf_kind(dist_t); + + /* Validate that the found distilled type is compatible. + * Do not error out on mismatch as another match may + * occur for an identically-named type. + */ + switch (dist_kind) { + case BTF_KIND_FWD: + switch (base_kind) { + case BTF_KIND_FWD: + if (btf_kflag(dist_t) != btf_kflag(base_t)) + continue; + break; + case BTF_KIND_STRUCT: + if (btf_kflag(base_t)) + continue; + break; + case BTF_KIND_UNION: + if (!btf_kflag(base_t)) + continue; + break; + default: + continue; + } + break; + case BTF_KIND_INT: + if (dist_kind != base_kind || + btf_int_encoding(base_t) != btf_int_encoding(dist_t)) + continue; + break; + case BTF_KIND_FLOAT: + if (dist_kind != base_kind) + continue; + break; + case BTF_KIND_ENUM: + /* ENUM and ENUM64 are encoded as sized ENUM in + * distilled base BTF. + */ + if (base_kind != dist_kind && base_kind != BTF_KIND_ENUM64) + continue; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* size verification is required for embedded + * struct/unions. + */ + if (r->id_map[dist_name_info->id] == BTF_IS_EMBEDDED && + base_t->size != dist_t->size) + continue; + break; + default: + continue; + } + if (r->id_map[dist_name_info->id] && + r->id_map[dist_name_info->id] != BTF_IS_EMBEDDED) { + /* we already have a match; this tells us that + * multiple base types of the same name + * have the same size, since for cases where + * multiple types have the same name we match + * on name and size. In this case, we have + * no way of determining which to relocate + * to in base BTF, so error out. + */ + pr_warn("distilled base BTF type '%s' [%u], size %u has multiple candidates of the same size (ids [%u, %u]) in base BTF\n", + base_name_info.name, dist_name_info->id, + base_t->size, id, r->id_map[dist_name_info->id]); + err = -EINVAL; + goto done; + } + /* map id and name */ + r->id_map[dist_name_info->id] = id; + r->str_map[dist_t->name_off] = base_t->name_off; + } + } + /* ensure all distilled BTF ids now have a mapping... */ + for (id = 1; id < r->nr_dist_base_types; id++) { + const char *name; + + if (r->id_map[id] && r->id_map[id] != BTF_IS_EMBEDDED) + continue; + dist_t = btf_type_by_id(r->dist_base_btf, id); + name = btf__name_by_offset(r->dist_base_btf, dist_t->name_off); + pr_warn("distilled base BTF type '%s' [%d] is not mapped to base BTF id\n", + name, id); + err = -EINVAL; + break; + } +done: + free(base_name_cnt); + free(dist_base_info_sorted); + return err; +} + +/* distilled base should only have named int/float/enum/fwd/struct/union types. */ +static int btf_relocate_validate_distilled_base(struct btf_relocate *r) +{ + unsigned int i; + + for (i = 1; i < r->nr_dist_base_types; i++) { + struct btf_type *t = btf_type_by_id(r->dist_base_btf, i); + int kind = btf_kind(t); + + switch (kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_FWD: + if (t->name_off) + break; + pr_warn("type [%d], kind [%d] is invalid for distilled base BTF; it is anonymous\n", + i, kind); + return -EINVAL; + default: + pr_warn("type [%d] in distilled based BTF has unexpected kind [%d]\n", + i, kind); + return -EINVAL; + } + } + return 0; +} + +static int btf_relocate_rewrite_strs(struct btf_relocate *r, __u32 i) +{ + struct btf_type *t = btf_type_by_id(r->btf, i); + struct btf_field_iter it; + __u32 *str_off; + int off, err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); + if (err) + return err; + + while ((str_off = btf_field_iter_next(&it))) { + if (!*str_off) + continue; + if (*str_off >= r->dist_str_len) { + *str_off += r->base_str_len - r->dist_str_len; + } else { + off = r->str_map[*str_off]; + if (!off) { + pr_warn("string '%s' [offset %u] is not mapped to base BTF", + btf__str_by_offset(r->btf, off), *str_off); + return -ENOENT; + } + *str_off = off; + } + } + return 0; +} + +/* If successful, output of relocation is updated BTF with base BTF pointing + * at base_btf, and type ids, strings adjusted accordingly. + */ +int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map) +{ + unsigned int nr_types = btf__type_cnt(btf); + const struct btf_header *dist_base_hdr; + const struct btf_header *base_hdr; + struct btf_relocate r = {}; + int err = 0; + __u32 id, i; + + r.dist_base_btf = btf__base_btf(btf); + if (!base_btf || r.dist_base_btf == base_btf) + return -EINVAL; + + r.nr_dist_base_types = btf__type_cnt(r.dist_base_btf); + r.nr_base_types = btf__type_cnt(base_btf); + r.nr_split_types = nr_types - r.nr_dist_base_types; + r.btf = btf; + r.base_btf = base_btf; + + r.id_map = calloc(nr_types, sizeof(*r.id_map)); + r.str_map = calloc(btf_header(r.dist_base_btf)->str_len, sizeof(*r.str_map)); + dist_base_hdr = btf_header(r.dist_base_btf); + base_hdr = btf_header(r.base_btf); + r.dist_str_len = dist_base_hdr->str_len; + r.base_str_len = base_hdr->str_len; + if (!r.id_map || !r.str_map) { + err = -ENOMEM; + goto err_out; + } + + err = btf_relocate_validate_distilled_base(&r); + if (err) + goto err_out; + + /* Split BTF ids need to be adjusted as base and distilled base + * have different numbers of types, changing the start id of split + * BTF. + */ + for (id = r.nr_dist_base_types; id < nr_types; id++) + r.id_map[id] = id + r.nr_base_types - r.nr_dist_base_types; + + /* Build a map from distilled base ids to actual base BTF ids; it is used + * to update split BTF id references. Also build a str_map mapping from + * distilled base BTF names to base BTF names. + */ + err = btf_relocate_map_distilled_base(&r); + if (err) + goto err_out; + + /* Next, rewrite type ids in split BTF, replacing split ids with updated + * ids based on number of types in base BTF, and base ids with + * relocated ids from base_btf. + */ + for (i = 0, id = r.nr_dist_base_types; i < r.nr_split_types; i++, id++) { + err = btf_relocate_rewrite_type_id(&r, id); + if (err) + goto err_out; + } + /* String offsets now need to be updated using the str_map. */ + for (i = 0; i < r.nr_split_types; i++) { + err = btf_relocate_rewrite_strs(&r, i + r.nr_dist_base_types); + if (err) + goto err_out; + } + /* Finally reset base BTF to be base_btf */ + btf_set_base_btf(btf, base_btf); + + if (id_map) { + *id_map = r.id_map; + r.id_map = NULL; + } +err_out: + free(r.id_map); + free(r.str_map); + return err; +} diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 40595233dc7f..8f0d9ea3b1b4 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -419,6 +419,8 @@ LIBBPF_1.4.0 { LIBBPF_1.5.0 { global: + btf__distill_base; + btf__relocate; bpf_map__autoattach; bpf_map__set_autoattach; bpf_program__attach_sockmap; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index e2f06609c624..408df59e0771 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -234,6 +234,9 @@ struct btf_type; struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id); const char *btf_kind_str(const struct btf_type *t); const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); +const struct btf_header *btf_header(const struct btf *btf); +void btf_set_base_btf(struct btf *btf, const struct btf *base_btf); +int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map); static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) { diff --git a/tools/testing/selftests/bpf/prog_tests/btf_distill.c b/tools/testing/selftests/bpf/prog_tests/btf_distill.c new file mode 100644 index 000000000000..bfbe795823a2 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/btf_distill.c @@ -0,0 +1,552 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024, Oracle and/or its affiliates. */ + +#include <test_progs.h> +#include <bpf/btf.h> +#include "btf_helpers.h" + +/* Fabricate base, split BTF with references to base types needed; then create + * split BTF with distilled base BTF and ensure expectations are met: + * - only referenced base types from split BTF are present + * - struct/union/enum are represented as empty unless anonymous, when they + * are represented in full in split BTF + */ +static void test_distilled_base(void) +{ + struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL; + + btf1 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf1, "empty_main_btf")) + return; + + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [1] int */ + btf__add_ptr(btf1, 1); /* [2] ptr to int */ + btf__add_struct(btf1, "s1", 8); /* [3] struct s1 { */ + btf__add_field(btf1, "f1", 2, 0, 0); /* int *f1; */ + /* } */ + btf__add_struct(btf1, "", 12); /* [4] struct { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + btf__add_field(btf1, "f2", 3, 32, 0); /* struct s1 f2; */ + /* } */ + btf__add_int(btf1, "unsigned int", 4, 0); /* [5] unsigned int */ + btf__add_union(btf1, "u1", 12); /* [6] union u1 { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + btf__add_field(btf1, "f2", 2, 0, 0); /* int *f2; */ + /* } */ + btf__add_union(btf1, "", 4); /* [7] union { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + /* } */ + btf__add_enum(btf1, "e1", 4); /* [8] enum e1 { */ + btf__add_enum_value(btf1, "v1", 1); /* v1 = 1; */ + /* } */ + btf__add_enum(btf1, "", 4); /* [9] enum { */ + btf__add_enum_value(btf1, "av1", 2); /* av1 = 2; */ + /* } */ + btf__add_enum64(btf1, "e641", 8, true); /* [10] enum64 { */ + btf__add_enum64_value(btf1, "v1", 1024); /* v1 = 1024; */ + /* } */ + btf__add_enum64(btf1, "", 8, true); /* [11] enum64 { */ + btf__add_enum64_value(btf1, "v1", 1025); /* v1 = 1025; */ + /* } */ + btf__add_struct(btf1, "unneeded", 4); /* [12] struct unneeded { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + /* } */ + btf__add_struct(btf1, "embedded", 4); /* [13] struct embedded { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + /* } */ + btf__add_func_proto(btf1, 1); /* [14] int (*)(int *p1); */ + btf__add_func_param(btf1, "p1", 1); + + btf__add_array(btf1, 1, 1, 3); /* [15] int [3]; */ + + btf__add_struct(btf1, "from_proto", 4); /* [16] struct from_proto { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + /* } */ + btf__add_union(btf1, "u1", 4); /* [17] union u1 { */ + btf__add_field(btf1, "f1", 1, 0, 0); /* int f1; */ + /* } */ + VALIDATE_RAW_BTF( + btf1, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] PTR '(anon)' type_id=1", + "[3] STRUCT 's1' size=8 vlen=1\n" + "\t'f1' type_id=2 bits_offset=0", + "[4] STRUCT '(anon)' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=3 bits_offset=32", + "[5] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)", + "[6] UNION 'u1' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=2 bits_offset=0", + "[7] UNION '(anon)' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[8] ENUM 'e1' encoding=UNSIGNED size=4 vlen=1\n" + "\t'v1' val=1", + "[9] ENUM '(anon)' encoding=UNSIGNED size=4 vlen=1\n" + "\t'av1' val=2", + "[10] ENUM64 'e641' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1024", + "[11] ENUM64 '(anon)' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1025", + "[12] STRUCT 'unneeded' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[13] STRUCT 'embedded' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[14] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[15] ARRAY '(anon)' type_id=1 index_type_id=1 nr_elems=3", + "[16] STRUCT 'from_proto' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[17] UNION 'u1' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0"); + + btf2 = btf__new_empty_split(btf1); + if (!ASSERT_OK_PTR(btf2, "empty_split_btf")) + goto cleanup; + + btf__add_ptr(btf2, 3); /* [18] ptr to struct s1 */ + /* add ptr to struct anon */ + btf__add_ptr(btf2, 4); /* [19] ptr to struct (anon) */ + btf__add_const(btf2, 6); /* [20] const union u1 */ + btf__add_restrict(btf2, 7); /* [21] restrict union (anon) */ + btf__add_volatile(btf2, 8); /* [22] volatile enum e1 */ + btf__add_typedef(btf2, "et", 9); /* [23] typedef enum (anon) */ + btf__add_const(btf2, 10); /* [24] const enum64 e641 */ + btf__add_ptr(btf2, 11); /* [25] restrict enum64 (anon) */ + btf__add_struct(btf2, "with_embedded", 4); /* [26] struct with_embedded { */ + btf__add_field(btf2, "f1", 13, 0, 0); /* struct embedded f1; */ + /* } */ + btf__add_func(btf2, "fn", BTF_FUNC_STATIC, 14); /* [27] int fn(int p1); */ + btf__add_typedef(btf2, "arraytype", 15); /* [28] typedef int[3] foo; */ + btf__add_func_proto(btf2, 1); /* [29] int (*)(struct from proto p1); */ + btf__add_func_param(btf2, "p1", 16); + + VALIDATE_RAW_BTF( + btf2, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] PTR '(anon)' type_id=1", + "[3] STRUCT 's1' size=8 vlen=1\n" + "\t'f1' type_id=2 bits_offset=0", + "[4] STRUCT '(anon)' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=3 bits_offset=32", + "[5] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)", + "[6] UNION 'u1' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=2 bits_offset=0", + "[7] UNION '(anon)' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[8] ENUM 'e1' encoding=UNSIGNED size=4 vlen=1\n" + "\t'v1' val=1", + "[9] ENUM '(anon)' encoding=UNSIGNED size=4 vlen=1\n" + "\t'av1' val=2", + "[10] ENUM64 'e641' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1024", + "[11] ENUM64 '(anon)' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1025", + "[12] STRUCT 'unneeded' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[13] STRUCT 'embedded' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[14] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[15] ARRAY '(anon)' type_id=1 index_type_id=1 nr_elems=3", + "[16] STRUCT 'from_proto' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[17] UNION 'u1' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[18] PTR '(anon)' type_id=3", + "[19] PTR '(anon)' type_id=4", + "[20] CONST '(anon)' type_id=6", + "[21] RESTRICT '(anon)' type_id=7", + "[22] VOLATILE '(anon)' type_id=8", + "[23] TYPEDEF 'et' type_id=9", + "[24] CONST '(anon)' type_id=10", + "[25] PTR '(anon)' type_id=11", + "[26] STRUCT 'with_embedded' size=4 vlen=1\n" + "\t'f1' type_id=13 bits_offset=0", + "[27] FUNC 'fn' type_id=14 linkage=static", + "[28] TYPEDEF 'arraytype' type_id=15", + "[29] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=16"); + + if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4), + "distilled_base") || + !ASSERT_OK_PTR(btf3, "distilled_base") || + !ASSERT_OK_PTR(btf4, "distilled_split") || + !ASSERT_EQ(8, btf__type_cnt(btf3), "distilled_base_type_cnt")) + goto cleanup; + + VALIDATE_RAW_BTF( + btf4, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] STRUCT 's1' size=8 vlen=0", + "[3] UNION 'u1' size=12 vlen=0", + "[4] ENUM 'e1' encoding=UNSIGNED size=4 vlen=0", + "[5] ENUM 'e641' encoding=UNSIGNED size=8 vlen=0", + "[6] STRUCT 'embedded' size=4 vlen=0", + "[7] STRUCT 'from_proto' size=4 vlen=0", + /* split BTF; these types should match split BTF above from 17-28, with + * updated type id references + */ + "[8] PTR '(anon)' type_id=2", + "[9] PTR '(anon)' type_id=20", + "[10] CONST '(anon)' type_id=3", + "[11] RESTRICT '(anon)' type_id=21", + "[12] VOLATILE '(anon)' type_id=4", + "[13] TYPEDEF 'et' type_id=22", + "[14] CONST '(anon)' type_id=5", + "[15] PTR '(anon)' type_id=23", + "[16] STRUCT 'with_embedded' size=4 vlen=1\n" + "\t'f1' type_id=6 bits_offset=0", + "[17] FUNC 'fn' type_id=24 linkage=static", + "[18] TYPEDEF 'arraytype' type_id=25", + "[19] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=7", + /* split BTF types added from original base BTF below */ + "[20] STRUCT '(anon)' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=2 bits_offset=32", + "[21] UNION '(anon)' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[22] ENUM '(anon)' encoding=UNSIGNED size=4 vlen=1\n" + "\t'av1' val=2", + "[23] ENUM64 '(anon)' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1025", + "[24] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[25] ARRAY '(anon)' type_id=1 index_type_id=1 nr_elems=3"); + + if (!ASSERT_EQ(btf__relocate(btf4, btf1), 0, "relocate_split")) + goto cleanup; + + VALIDATE_RAW_BTF( + btf4, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] PTR '(anon)' type_id=1", + "[3] STRUCT 's1' size=8 vlen=1\n" + "\t'f1' type_id=2 bits_offset=0", + "[4] STRUCT '(anon)' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=3 bits_offset=32", + "[5] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)", + "[6] UNION 'u1' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=2 bits_offset=0", + "[7] UNION '(anon)' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[8] ENUM 'e1' encoding=UNSIGNED size=4 vlen=1\n" + "\t'v1' val=1", + "[9] ENUM '(anon)' encoding=UNSIGNED size=4 vlen=1\n" + "\t'av1' val=2", + "[10] ENUM64 'e641' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1024", + "[11] ENUM64 '(anon)' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1025", + "[12] STRUCT 'unneeded' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[13] STRUCT 'embedded' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[14] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[15] ARRAY '(anon)' type_id=1 index_type_id=1 nr_elems=3", + "[16] STRUCT 'from_proto' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[17] UNION 'u1' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[18] PTR '(anon)' type_id=3", + "[19] PTR '(anon)' type_id=30", + "[20] CONST '(anon)' type_id=6", + "[21] RESTRICT '(anon)' type_id=31", + "[22] VOLATILE '(anon)' type_id=8", + "[23] TYPEDEF 'et' type_id=32", + "[24] CONST '(anon)' type_id=10", + "[25] PTR '(anon)' type_id=33", + "[26] STRUCT 'with_embedded' size=4 vlen=1\n" + "\t'f1' type_id=13 bits_offset=0", + "[27] FUNC 'fn' type_id=34 linkage=static", + "[28] TYPEDEF 'arraytype' type_id=35", + "[29] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=16", + /* below here are (duplicate) anon base types added by distill + * process to split BTF. + */ + "[30] STRUCT '(anon)' size=12 vlen=2\n" + "\t'f1' type_id=1 bits_offset=0\n" + "\t'f2' type_id=3 bits_offset=32", + "[31] UNION '(anon)' size=4 vlen=1\n" + "\t'f1' type_id=1 bits_offset=0", + "[32] ENUM '(anon)' encoding=UNSIGNED size=4 vlen=1\n" + "\t'av1' val=2", + "[33] ENUM64 '(anon)' encoding=SIGNED size=8 vlen=1\n" + "\t'v1' val=1025", + "[34] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[35] ARRAY '(anon)' type_id=1 index_type_id=1 nr_elems=3"); + +cleanup: + btf__free(btf4); + btf__free(btf3); + btf__free(btf2); + btf__free(btf1); +} + +/* ensure we can cope with multiple types with the same name in + * distilled base BTF. In this case because sizes are different, + * we can still disambiguate them. + */ +static void test_distilled_base_multi(void) +{ + struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL; + + btf1 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf1, "empty_main_btf")) + return; + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [1] int */ + btf__add_int(btf1, "int", 8, BTF_INT_SIGNED); /* [2] int */ + VALIDATE_RAW_BTF( + btf1, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED"); + btf2 = btf__new_empty_split(btf1); + if (!ASSERT_OK_PTR(btf2, "empty_split_btf")) + goto cleanup; + btf__add_ptr(btf2, 1); + btf__add_const(btf2, 2); + VALIDATE_RAW_BTF( + btf2, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED", + "[3] PTR '(anon)' type_id=1", + "[4] CONST '(anon)' type_id=2"); + if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4), + "distilled_base") || + !ASSERT_OK_PTR(btf3, "distilled_base") || + !ASSERT_OK_PTR(btf4, "distilled_split") || + !ASSERT_EQ(3, btf__type_cnt(btf3), "distilled_base_type_cnt")) + goto cleanup; + VALIDATE_RAW_BTF( + btf3, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED"); + if (!ASSERT_EQ(btf__relocate(btf4, btf1), 0, "relocate_split")) + goto cleanup; + + VALIDATE_RAW_BTF( + btf4, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED", + "[3] PTR '(anon)' type_id=1", + "[4] CONST '(anon)' type_id=2"); + +cleanup: + btf__free(btf4); + btf__free(btf3); + btf__free(btf2); + btf__free(btf1); +} + +/* If a needed type is not present in the base BTF we wish to relocate + * with, btf__relocate() should error our. + */ +static void test_distilled_base_missing_err(void) +{ + struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL, *btf5 = NULL; + + btf1 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf1, "empty_main_btf")) + return; + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [1] int */ + btf__add_int(btf1, "int", 8, BTF_INT_SIGNED); /* [2] int */ + VALIDATE_RAW_BTF( + btf1, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED"); + btf2 = btf__new_empty_split(btf1); + if (!ASSERT_OK_PTR(btf2, "empty_split_btf")) + goto cleanup; + btf__add_ptr(btf2, 1); + btf__add_const(btf2, 2); + VALIDATE_RAW_BTF( + btf2, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED", + "[3] PTR '(anon)' type_id=1", + "[4] CONST '(anon)' type_id=2"); + if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4), + "distilled_base") || + !ASSERT_OK_PTR(btf3, "distilled_base") || + !ASSERT_OK_PTR(btf4, "distilled_split") || + !ASSERT_EQ(3, btf__type_cnt(btf3), "distilled_base_type_cnt")) + goto cleanup; + VALIDATE_RAW_BTF( + btf3, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED"); + btf5 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf5, "empty_reloc_btf")) + return; + btf__add_int(btf5, "int", 4, BTF_INT_SIGNED); /* [1] int */ + VALIDATE_RAW_BTF( + btf5, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED"); + ASSERT_EQ(btf__relocate(btf4, btf5), -EINVAL, "relocate_split"); + +cleanup: + btf__free(btf5); + btf__free(btf4); + btf__free(btf3); + btf__free(btf2); + btf__free(btf1); +} + +/* With 2 types of same size in distilled base BTF, relocation should + * fail as we have no means to choose between them. + */ +static void test_distilled_base_multi_err(void) +{ + struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL; + + btf1 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf1, "empty_main_btf")) + return; + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [1] int */ + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [2] int */ + VALIDATE_RAW_BTF( + btf1, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED"); + btf2 = btf__new_empty_split(btf1); + if (!ASSERT_OK_PTR(btf2, "empty_split_btf")) + goto cleanup; + btf__add_ptr(btf2, 1); + btf__add_const(btf2, 2); + VALIDATE_RAW_BTF( + btf2, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[3] PTR '(anon)' type_id=1", + "[4] CONST '(anon)' type_id=2"); + if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4), + "distilled_base") || + !ASSERT_OK_PTR(btf3, "distilled_base") || + !ASSERT_OK_PTR(btf4, "distilled_split") || + !ASSERT_EQ(3, btf__type_cnt(btf3), "distilled_base_type_cnt")) + goto cleanup; + VALIDATE_RAW_BTF( + btf3, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED"); + ASSERT_EQ(btf__relocate(btf4, btf1), -EINVAL, "relocate_split"); +cleanup: + btf__free(btf4); + btf__free(btf3); + btf__free(btf2); + btf__free(btf1); +} + +/* With 2 types of same size in base BTF, relocation should + * fail as we have no means to choose between them. + */ +static void test_distilled_base_multi_err2(void) +{ + struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL, *btf5 = NULL; + + btf1 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf1, "empty_main_btf")) + return; + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [1] int */ + VALIDATE_RAW_BTF( + btf1, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED"); + btf2 = btf__new_empty_split(btf1); + if (!ASSERT_OK_PTR(btf2, "empty_split_btf")) + goto cleanup; + btf__add_ptr(btf2, 1); + VALIDATE_RAW_BTF( + btf2, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] PTR '(anon)' type_id=1"); + if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4), + "distilled_base") || + !ASSERT_OK_PTR(btf3, "distilled_base") || + !ASSERT_OK_PTR(btf4, "distilled_split") || + !ASSERT_EQ(2, btf__type_cnt(btf3), "distilled_base_type_cnt")) + goto cleanup; + VALIDATE_RAW_BTF( + btf3, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED"); + btf5 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf5, "empty_reloc_btf")) + return; + btf__add_int(btf5, "int", 4, BTF_INT_SIGNED); /* [1] int */ + btf__add_int(btf5, "int", 4, BTF_INT_SIGNED); /* [2] int */ + VALIDATE_RAW_BTF( + btf5, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED"); + ASSERT_EQ(btf__relocate(btf4, btf5), -EINVAL, "relocate_split"); +cleanup: + btf__free(btf5); + btf__free(btf4); + btf__free(btf3); + btf__free(btf2); + btf__free(btf1); +} + +/* create split reference BTF from vmlinux + split BTF with a few type references; + * ensure the resultant split reference BTF is as expected, containing only types + * needed to disambiguate references from split BTF. + */ +static void test_distilled_base_vmlinux(void) +{ + struct btf *split_btf = NULL, *vmlinux_btf = btf__load_vmlinux_btf(); + struct btf *split_dist = NULL, *base_dist = NULL; + __s32 int_id, myint_id; + + if (!ASSERT_OK_PTR(vmlinux_btf, "load_vmlinux")) + return; + int_id = btf__find_by_name_kind(vmlinux_btf, "int", BTF_KIND_INT); + if (!ASSERT_GT(int_id, 0, "find_int")) + goto cleanup; + split_btf = btf__new_empty_split(vmlinux_btf); + if (!ASSERT_OK_PTR(split_btf, "new_split")) + goto cleanup; + myint_id = btf__add_typedef(split_btf, "myint", int_id); + btf__add_ptr(split_btf, myint_id); + + if (!ASSERT_EQ(btf__distill_base(split_btf, &base_dist, &split_dist), 0, + "distill_vmlinux_base")) + goto cleanup; + + if (!ASSERT_OK_PTR(split_dist, "split_distilled") || + !ASSERT_OK_PTR(base_dist, "base_dist")) + goto cleanup; + VALIDATE_RAW_BTF( + split_dist, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] TYPEDEF 'myint' type_id=1", + "[3] PTR '(anon)' type_id=2"); + +cleanup: + btf__free(split_dist); + btf__free(base_dist); + btf__free(split_btf); + btf__free(vmlinux_btf); +} + +void test_btf_distill(void) +{ + if (test__start_subtest("distilled_base")) + test_distilled_base(); + if (test__start_subtest("distilled_base_multi")) + test_distilled_base_multi(); + if (test__start_subtest("distilled_base_missing_err")) + test_distilled_base_missing_err(); + if (test__start_subtest("distilled_base_multi_err")) + test_distilled_base_multi_err(); + if (test__start_subtest("distilled_base_multi_err2")) + test_distilled_base_multi_err2(); + if (test__start_subtest("distilled_base_vmlinux")) + test_distilled_base_vmlinux(); +} |