This patch introduces bpf__{un,}probe() functions to enable callers to
create kprobe points based on section names of BPF programs. It parses
the section names of each eBPF program and creates corresponding 'struct
perf_probe_event' structures. The parse_perf_probe_command() function is
used to do the main parsing work.Parsing result is stored into an array to satisify add_perf_probe_events(). It accepts an array of 'struct perf_probe_event' and do all the work in one call. Define PERF_BPF_PROBE_GROUP as "perf_bpf_probe", which will be used as the group name of all eBPF probing points. probe_conf.max_probes is set to MAX_PROBES to support glob matching. Before ending of bpf__probe(), data in each 'struct perf_probe_event' is cleaned. Things will be changed by following patches because they need 'struct probe_trace_event' in them, Signed-off-by: Wang Nan <wangn...@huawei.com> Cc: Alexei Starovoitov <a...@plumgrid.com> Cc: Brendan Gregg <brendan.d.gr...@gmail.com> Cc: Daniel Borkmann <dan...@iogearbox.net> Cc: David Ahern <dsah...@gmail.com> Cc: He Kuang <heku...@huawei.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Kaixu Xia <xiaka...@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Zefan Li <lize...@huawei.com> Cc: pi3or...@163.com Link: http://lkml.kernel.org/n/1436445342-1402-21-git-send-email-wangn...@huawei.com Link: http://lkml.kernel.org/n/1436445342-1402-23-git-send-email-wangn...@huawei.com [Merged by two patches] Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/builtin-record.c | 19 ++++++- tools/perf/util/bpf-loader.c | 133 +++++++++++++++++++++++++++++++++++++++++++ tools/perf/util/bpf-loader.h | 13 +++++ 3 files changed, 164 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 31934b1..8833186 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1140,7 +1140,23 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused) if (err) goto out_bpf_clear; - err = -ENOMEM; + /* + * bpf__probe must be called before symbol__init() because we + * need init_symbol_maps. If called after symbol__init, + * symbol_conf.sort_by_name won't take effect. + * + * bpf__unprobe() is safe even if bpf__probe() failed, and it + * also calls symbol__init. Therefore, goto out_symbol_exit + * is safe when probe failed. + */ + err = bpf__probe(); + if (err) { + bpf__strerror_probe(err, errbuf, sizeof(errbuf)); + + pr_err("Probing at events in BPF object failed.\n"); + pr_err("\t%s\n", errbuf); + goto out_symbol_exit; + } symbol__init(NULL); @@ -1201,6 +1217,7 @@ out_symbol_exit: perf_evlist__delete(rec->evlist); symbol__exit(); auxtrace_record__free(rec->itr); + bpf__unprobe(); out_bpf_clear: bpf__clear(); return err; diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 88531ea..435f52e 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -9,6 +9,8 @@ #include "perf.h" #include "debug.h" #include "bpf-loader.h" +#include "probe-event.h" +#include "probe-finder.h" #define DEFINE_PRINT_FN(name, level) \ static int libbpf_##name(const char *fmt, ...) \ @@ -28,6 +30,58 @@ DEFINE_PRINT_FN(debug, 1) static bool libbpf_initialized; +static int +config_bpf_program(struct bpf_program *prog, struct perf_probe_event *pev) +{ + 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; + } + + 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); + /* parse failed, don't need clear pev. */ + return -EINVAL; + } + + 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); + + return 0; + +errout: + if (pev) + clear_perf_probe_event(pev); + return err; +} + int bpf__prepare_load(const char *filename) { struct bpf_object *obj; @@ -59,6 +113,74 @@ void bpf__clear(void) bpf_object__close(obj); } +static bool is_probed; + +int bpf__unprobe(void) +{ + struct strfilter *delfilter; + int ret; + + if (!is_probed) + return 0; + + delfilter = strfilter__new(PERF_BPF_PROBE_GROUP ":*", NULL); + if (!delfilter) { + pr_debug("Failed to create delfilter when unprobing\n"); + return -ENOMEM; + } + + ret = del_perf_probe_events(delfilter); + strfilter__delete(delfilter); + if (ret < 0 && is_probed) + pr_debug("Error: failed to delete events: %s\n", + strerror(-ret)); + else + is_probed = false; + return ret < 0 ? ret : 0; +} + +int bpf__probe(void) +{ + int err, nr_events = 0; + struct bpf_object *obj, *tmp; + struct bpf_program *prog; + struct perf_probe_event *pevs; + + pevs = calloc(MAX_PROBES, sizeof(pevs[0])); + if (!pevs) + return -ENOMEM; + + bpf_object__for_each_safe(obj, tmp) { + bpf_object__for_each_program(prog, obj) { + err = config_bpf_program(prog, &pevs[nr_events++]); + if (err < 0) + goto out; + + if (nr_events >= MAX_PROBES) { + pr_debug("Too many (more than %d) events\n", + MAX_PROBES); + err = -ERANGE; + goto out; + }; + } + } + + probe_conf.max_probes = MAX_PROBES; + /* Let add_perf_probe_events generates probe_trace_event (tevs) */ + err = add_perf_probe_events(pevs, nr_events, false); + + /* add_perf_probe_events return negative when fail */ + if (err < 0) { + pr_debug("bpf probe: failed to probe events\n"); + } else + is_probed = true; +out: + while (nr_events > 0) + clear_perf_probe_event(&pevs[--nr_events]); + free(pevs); + return err < 0 ? err : 0; +} + #define bpf__strerror_head(err, buf, size) \ char sbuf[STRERR_BUFSIZE], *emsg;\ if (!size)\ @@ -90,3 +212,14 @@ int bpf__strerror_prepare_load(const char *filename, int err, bpf__strerror_end(buf, size); return 0; } + +int bpf__strerror_probe(int err, char *buf, size_t size) +{ + bpf__strerror_head(err, buf, size); + bpf__strerror_entry(ERANGE, "Too many (more than %d) events", + MAX_PROBES); + bpf__strerror_entry(ENOENT, "Selected kprobe point doesn't exist."); + bpf__strerror_entry(EEXIST, "Selected kprobe point already exist, try perf probe -d '*'."); + bpf__strerror_end(buf, size); + return 0; +} diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h index 12be630..6b09a85 100644 --- a/tools/perf/util/bpf-loader.h +++ b/tools/perf/util/bpf-loader.h @@ -9,10 +9,15 @@ #include <string.h> #include "debug.h" +#define PERF_BPF_PROBE_GROUP "perf_bpf_probe" + #ifdef HAVE_LIBBPF_SUPPORT int bpf__prepare_load(const char *filename); int bpf__strerror_prepare_load(const char *filename, int err, char *buf, size_t size); +int bpf__probe(void); +int bpf__unprobe(void); +int bpf__strerror_probe(int err, char *buf, size_t size); void bpf__clear(void); #else @@ -22,6 +27,8 @@ static inline int bpf__prepare_load(const char *filename __maybe_unused) return -1; } +static inline int bpf__probe(void) { return 0; } +static inline int bpf__unprobe(void) { return 0; } static inline void bpf__clear(void) { } static inline int @@ -43,5 +50,11 @@ bpf__strerror_prepare_load(const char *filename __maybe_unused, { return __bpf_strerror(buf, size); } + +static inline int bpf__strerror_probe(int err __maybe_unused, + char *buf, size_t size) +{ + return __bpf_strerror(buf, size); +} #endif #endif -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
