From 03e01f568759ddbfdaff892e299758e7771a3478 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 16 Nov 2015 12:10:08 +0000 Subject: [PATCH] perf bpf: Allow BPF program config probing options By extending the syntax of BPF object section names, this patch allows users to config probing options like what they can do in 'perf probe'. The error message in 'perf probe' is also updated. Test result: For following BPF file test_probe_glob.c: # cat test_probe_glob.c __attribute__((section("inlines=no;func=SyS_dup?"), used)) int func(void *ctx) { return 1; } char _license[] __attribute__((section("license"), used)) = "GPL"; int _version __attribute__((section("version"), used)) = 0x40300; # # ./perf record -e ./test_probe_glob.c ls / ... [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.013 MB perf.data ] # ./perf evlist perf_bpf_probe:func_1 perf_bpf_probe:func After changing "inlines=no" to "inlines=yes": # ./perf record -e ./test_probe_glob.c ls / ... [ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 0.013 MB perf.data ] # ./perf evlist perf_bpf_probe:func_3 perf_bpf_probe:func_2 perf_bpf_probe:func_1 perf_bpf_probe:func Then test 'force': Use following program: # cat test_probe_force.c __attribute__((section("func=sys_write"), used)) int funca(void *ctx) { return 1; } __attribute__((section("force=yes;func=sys_write"), used)) int funcb(void *ctx) { return 1; } char _license[] __attribute__((section("license"), used)) = "GPL"; int _version __attribute__((section("version"), used)) = 0x40300; # # perf record -e ./test_probe_force.c usleep 1 Error: event "func" already exists. Hint: Remove existing event by 'perf probe -d' or force duplicates by 'perf probe -f' or set 'force=yes' in BPF source. event syntax error: './test_probe_force.c' \___ Probe point exist. Try 'perf probe -d "*"' and set 'force=yes' (add -v to see detail) ... Then replace 'force=no' to 'force=yes': # vim test_probe_force.c # perf record -e ./test_probe_force.c usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.017 MB perf.data ] # perf evlist perf_bpf_probe:func_1 perf_bpf_probe:func # Signed-off-by: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Masami Hiramatsu Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-7-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 53 +++++++++++++++++++++++++++++++++-- tools/perf/util/probe-event.c | 7 +++-- 2 files changed, 56 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index d0f02ed93804..98f2e5d1a5be 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -7,6 +7,7 @@ #include #include +#include #include "perf.h" #include "debug.h" #include "bpf-loader.h" @@ -129,6 +130,38 @@ config__module(const char *value, struct perf_probe_event *pev) return 0; } +static int +config__bool(const char *value, + bool *pbool, bool invert) +{ + int err; + bool bool_value; + + if (!pbool) + return -EINVAL; + + err = strtobool(value, &bool_value); + if (err) + return err; + + *pbool = invert ? !bool_value : bool_value; + return 0; +} + +static int +config__inlines(const char *value, + struct perf_probe_event *pev __maybe_unused) +{ + return config__bool(value, &probe_conf.no_inlines, true); +} + +static int +config__force(const char *value, + struct perf_probe_event *pev __maybe_unused) +{ + return config__bool(value, &probe_conf.force_add, false); +} + static struct { const char *key; const char *usage; @@ -146,7 +179,19 @@ static struct { .usage = "module= ", .desc = "Set kprobe module", .func = config__module, - } + }, + { + .key = "inlines", + .usage = "inlines=[yes|no] ", + .desc = "Probe at inline symbol", + .func = config__inlines, + }, + { + .key = "force", + .usage = "force=[yes|no] ", + .desc = "Forcibly add events with existing name", + .func = config__force, + }, }; static int @@ -240,6 +285,10 @@ config_bpf_program(struct bpf_program *prog) const char *config_str; int err; + /* Initialize per-program probing setting */ + probe_conf.no_inlines = false; + probe_conf.force_add = false; + config_str = bpf_program__title(prog, false); if (IS_ERR(config_str)) { pr_debug("bpf: unable to get title for program\n"); @@ -544,7 +593,7 @@ int bpf__strerror_probe(struct bpf_object *obj __maybe_unused, scnprintf(buf, size, "%s (add -v to see detail)", emsg); break; } - bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'"); + bpf__strerror_entry(EEXIST, "Probe point exist. Try 'perf probe -d \"*\"' and set 'force=yes'"); bpf__strerror_entry(EACCES, "You need to be root"); bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0"); bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file"); diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 03875f9154e7..93996ec4bbe3 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -2326,8 +2326,11 @@ static int get_new_event_name(char *buf, size_t len, const char *base, goto out; if (!allow_suffix) { - pr_warning("Error: event \"%s\" already exists. " - "(Use -f to force duplicates.)\n", buf); + pr_warning("Error: event \"%s\" already exists.\n" + " Hint: Remove existing event by 'perf probe -d'\n" + " or force duplicates by 'perf probe -f'\n" + " or set 'force=yes' in BPF source.\n", + buf); ret = -EEXIST; goto out; }