diff options
author | Ingo Molnar <mingo@kernel.org> | 2015-10-29 13:17:56 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2015-10-29 13:17:56 +0100 |
commit | 66a565c203bc31b76969711fbd92da11bee2f129 (patch) | |
tree | 1d5a60b14b9f808b3c0cece5761002ad32f0e274 /tools/perf/util/bpf-loader.c | |
parent | 6fc774ef4ceca99c35dd3fb230dab618f78c8d6f (diff) | |
parent | 4edf30e39e6cff32390eaff6a1508969b3cd967b (diff) |
Merge tag 'perf-ebpf-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull basic perf/ebpf integration:
"Please see the changeset comments, but this is the very basic integration of
perf with libbpf that, given a .o file built for the 'bpf' target with clang,
will get it validated and loaded into the kernel via the sys_bpf syscall, which
can be seen using 'perf trace' to trace the whole thing looking just for the
bpf and perf_event_open syscalls:
# perf trace -e bpf,perf_event_open perf record -g --event /tmp/foo.o -a
362.779 ( 0.129 ms): perf/22408 bpf(cmd: 5, uattr: 0x7ffd4edb6db0, size: 48 ) = 3
384.192 ( 0.016 ms): perf/22408 perf_event_open(attr_uptr: 0x7ffd4edbace0, pid: -1, cpu: 3, group_fd: -1, flags: FD_CLOEXEC) = 5
384.247 ( 0.038 ms): perf/22408 perf_event_open(attr_uptr: 0x37aedd8, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 5
384.261 ( 0.007 ms): perf/22408 perf_event_open(attr_uptr: 0x37aedd8, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 5
387.680 ( 3.413 ms): perf/22408 perf_event_open(attr_uptr: 0x3222f08, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 5
387.688 ( 0.005 ms): perf/22408 perf_event_open(attr_uptr: 0x3222f08, pid: -1, cpu: 1, group_fd: -1, flags: FD_CLOEXEC) = 6
387.693 ( 0.004 ms): perf/22408 perf_event_open(attr_uptr: 0x3222f08, pid: -1, cpu: 2, group_fd: -1, flags: FD_CLOEXEC) = 7
387.698 ( 0.003 ms): perf/22408 perf_event_open(attr_uptr: 0x3222f08, pid: -1, cpu: 3, group_fd: -1, flags: FD_CLOEXEC) = 8
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.221 MB perf.data (2 samples) ]
# perf script
bash 18389 [002] 83446.412607: perf_bpf_probe:fork: (ffffffff8109be30)
29be31 _do_fork (/lib/modules/4.3.0-rc6+/build/vmlinux)
96d662 tracesys_phase2 (/lib/modules/4.3.0-rc6+/build/vmlinux)
bd56c __libc_fork (/usr/lib64/libc-2.17.so)
413b2 make_child (/usr/bin/bash)
bash 18389 [002] 83447.227255: perf_bpf_probe:fork: (ffffffff8109be30)
29be31 _do_fork (/lib/modules/4.3.0-rc6+/build/vmlinux)
96d662 tracesys_phase2 (/lib/modules/4.3.0-rc6+/build/vmlinux)
bd56c __libc_fork (/usr/lib64/libc-2.17.so)
413b2 make_child (/usr/bin/bash)
# perf evlist -v
perf_bpf_probe:fork: type: 2, size: 112, config: 0x6cf, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD|RAW, disabled: 1, inherit: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
#
More work is about to be reviewed, tested and merged that will allow the whole
process of going from a .c file to an .o file via clang, etc to be done
automagically. (Wang Nan)"
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/perf/util/bpf-loader.c')
-rw-r--r-- | tools/perf/util/bpf-loader.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c new file mode 100644 index 000000000000..aa784a498c48 --- /dev/null +++ b/tools/perf/util/bpf-loader.c @@ -0,0 +1,339 @@ +/* + * bpf-loader.c + * + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015 Huawei Inc. + */ + +#include <bpf/libbpf.h> +#include <linux/err.h> +#include "perf.h" +#include "debug.h" +#include "bpf-loader.h" +#include "probe-event.h" +#include "probe-finder.h" // for MAX_PROBES + +#define DEFINE_PRINT_FN(name, level) \ +static int libbpf_##name(const char *fmt, ...) \ +{ \ + va_list args; \ + int ret; \ + \ + va_start(args, fmt); \ + ret = veprintf(level, verbose, pr_fmt(fmt), args);\ + va_end(args); \ + return ret; \ +} + +DEFINE_PRINT_FN(warning, 0) +DEFINE_PRINT_FN(info, 0) +DEFINE_PRINT_FN(debug, 1) + +struct bpf_prog_priv { + struct perf_probe_event pev; +}; + +struct bpf_object *bpf__prepare_load(const char *filename) +{ + struct bpf_object *obj; + static bool libbpf_initialized; + + if (!libbpf_initialized) { + libbpf_set_print(libbpf_warning, + libbpf_info, + libbpf_debug); + libbpf_initialized = true; + } + + obj = bpf_object__open(filename); + if (!obj) { + pr_debug("bpf: failed to load %s\n", filename); + return ERR_PTR(-EINVAL); + } + + return obj; +} + +void bpf__clear(void) +{ + struct bpf_object *obj, *tmp; + + bpf_object__for_each_safe(obj, tmp) { + bpf__unprobe(obj); + bpf_object__close(obj); + } +} + +static void +bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused, + void *_priv) +{ + struct bpf_prog_priv *priv = _priv; + + cleanup_perf_probe_events(&priv->pev, 1); + free(priv); +} + +static int +config_bpf_program(struct bpf_program *prog) +{ + struct perf_probe_event *pev = NULL; + struct bpf_prog_priv *priv = NULL; + const char *config_str; + int err; + + config_str = bpf_program__title(prog, false); + if (!config_str) { + pr_debug("bpf: unable to get title for program\n"); + return -EINVAL; + } + + priv = calloc(sizeof(*priv), 1); + if (!priv) { + pr_debug("bpf: failed to alloc priv\n"); + return -ENOMEM; + } + pev = &priv->pev; + + pr_debug("bpf: config program '%s'\n", config_str); + err = parse_perf_probe_command(config_str, pev); + if (err < 0) { + pr_debug("bpf: '%s' is not a valid config string\n", + config_str); + err = -EINVAL; + goto errout; + } + + if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) { + pr_debug("bpf: '%s': group for event is set and not '%s'.\n", + config_str, PERF_BPF_PROBE_GROUP); + err = -EINVAL; + goto errout; + } else if (!pev->group) + pev->group = strdup(PERF_BPF_PROBE_GROUP); + + if (!pev->group) { + pr_debug("bpf: strdup failed\n"); + err = -ENOMEM; + goto errout; + } + + if (!pev->event) { + pr_debug("bpf: '%s': event name is missing\n", + config_str); + err = -EINVAL; + goto errout; + } + pr_debug("bpf: config '%s' is ok\n", config_str); + + err = bpf_program__set_private(prog, priv, bpf_prog_priv__clear); + if (err) { + pr_debug("Failed to set priv for program '%s'\n", config_str); + goto errout; + } + + return 0; + +errout: + if (pev) + clear_perf_probe_event(pev); + free(priv); + return err; +} + +static int bpf__prepare_probe(void) +{ + static int err = 0; + static bool initialized = false; + + /* + * Make err static, so if init failed the first, bpf__prepare_probe() + * fails each time without calling init_probe_symbol_maps multiple + * times. + */ + if (initialized) + return err; + + initialized = true; + err = init_probe_symbol_maps(false); + if (err < 0) + pr_debug("Failed to init_probe_symbol_maps\n"); + probe_conf.max_probes = MAX_PROBES; + return err; +} + +int bpf__probe(struct bpf_object *obj) +{ + int err = 0; + struct bpf_program *prog; + struct bpf_prog_priv *priv; + struct perf_probe_event *pev; + + err = bpf__prepare_probe(); + if (err) { + pr_debug("bpf__prepare_probe failed\n"); + return err; + } + + bpf_object__for_each_program(prog, obj) { + err = config_bpf_program(prog); + if (err) + goto out; + + err = bpf_program__get_private(prog, (void **)&priv); + if (err || !priv) + goto out; + pev = &priv->pev; + + err = convert_perf_probe_events(pev, 1); + if (err < 0) { + pr_debug("bpf_probe: failed to convert perf probe events"); + goto out; + } + + err = apply_perf_probe_events(pev, 1); + if (err < 0) { + pr_debug("bpf_probe: failed to apply perf probe events"); + goto out; + } + } +out: + return err < 0 ? err : 0; +} + +#define EVENTS_WRITE_BUFSIZE 4096 +int bpf__unprobe(struct bpf_object *obj) +{ + int err, ret = 0; + struct bpf_program *prog; + struct bpf_prog_priv *priv; + + bpf_object__for_each_program(prog, obj) { + int i; + + err = bpf_program__get_private(prog, (void **)&priv); + if (err || !priv) + continue; + + for (i = 0; i < priv->pev.ntevs; i++) { + struct probe_trace_event *tev = &priv->pev.tevs[i]; + char name_buf[EVENTS_WRITE_BUFSIZE]; + struct strfilter *delfilter; + + snprintf(name_buf, EVENTS_WRITE_BUFSIZE, + "%s:%s", tev->group, tev->event); + name_buf[EVENTS_WRITE_BUFSIZE - 1] = '\0'; + + delfilter = strfilter__new(name_buf, NULL); + if (!delfilter) { + pr_debug("Failed to create filter for unprobing\n"); + ret = -ENOMEM; + continue; + } + + err = del_perf_probe_events(delfilter); + strfilter__delete(delfilter); + if (err) { + pr_debug("Failed to delete %s\n", name_buf); + ret = err; + continue; + } + } + } + return ret; +} + +int bpf__load(struct bpf_object *obj) +{ + int err; + + err = bpf_object__load(obj); + if (err) { + pr_debug("bpf: load objects failed\n"); + return err; + } + return 0; +} + +int bpf__foreach_tev(struct bpf_object *obj, + bpf_prog_iter_callback_t func, + void *arg) +{ + struct bpf_program *prog; + int err; + + bpf_object__for_each_program(prog, obj) { + struct probe_trace_event *tev; + struct perf_probe_event *pev; + struct bpf_prog_priv *priv; + int i, fd; + + err = bpf_program__get_private(prog, + (void **)&priv); + if (err || !priv) { + pr_debug("bpf: failed to get private field\n"); + return -EINVAL; + } + + pev = &priv->pev; + for (i = 0; i < pev->ntevs; i++) { + tev = &pev->tevs[i]; + + fd = bpf_program__fd(prog); + if (fd < 0) { + pr_debug("bpf: failed to get file descriptor\n"); + return fd; + } + + err = (*func)(tev, fd, arg); + if (err) { + pr_debug("bpf: call back failed, stop iterate\n"); + return err; + } + } + } + return 0; +} + +#define bpf__strerror_head(err, buf, size) \ + char sbuf[STRERR_BUFSIZE], *emsg;\ + if (!size)\ + return 0;\ + if (err < 0)\ + err = -err;\ + emsg = strerror_r(err, sbuf, sizeof(sbuf));\ + switch (err) {\ + default:\ + scnprintf(buf, size, "%s", emsg);\ + break; + +#define bpf__strerror_entry(val, fmt...)\ + case val: {\ + scnprintf(buf, size, fmt);\ + break;\ + } + +#define bpf__strerror_end(buf, size)\ + }\ + buf[size - 1] = '\0'; + +int bpf__strerror_probe(struct bpf_object *obj __maybe_unused, + int err, char *buf, size_t size) +{ + bpf__strerror_head(err, buf, size); + bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'"); + bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0\n"); + bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file\n"); + bpf__strerror_end(buf, size); + return 0; +} + +int bpf__strerror_load(struct bpf_object *obj __maybe_unused, + int err, char *buf, size_t size) +{ + bpf__strerror_head(err, buf, size); + bpf__strerror_entry(EINVAL, "%s: Are you root and runing a CONFIG_BPF_SYSCALL kernel?", + emsg) + bpf__strerror_end(buf, size); + return 0; +} |