From 1e5e3ee8ff3877db6943032b54a6ac21c095affd Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Wed, 14 Oct 2015 12:41:16 +0000 Subject: [PATCH] perf tools: Load eBPF object into kernel This patch utilizes bpf_object__load() provided by libbpf to load all objects into kernel. Committer notes: Testing it: When using an incorrect kernel version number, i.e., having this in your eBPF proggie: int _version __attribute__((section("version"), used)) = 0x40100; For a 4.3.0-rc6+ kernel, say, this happens and needs checking at event parsing time, to provide a better error report to the user: # perf record --event /tmp/foo.o sleep 1 libbpf: load bpf program failed: Invalid argument libbpf: -- BEGIN DUMP LOG --- libbpf: libbpf: -- END LOG -- libbpf: failed to load program 'fork=_do_fork' libbpf: failed to load object '/tmp/foo.o' event syntax error: '/tmp/foo.o' \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel? (add -v to see detail) Run 'perf list' for a list of valid events Usage: perf record [] [] or: perf record [] -- [] -e, --event event selector. use 'perf list' to list available events If we instead make it match, i.e. use 0x40300 on this v4.3.0-rc6+ kernel, the whole process goes thru: # perf record --event /tmp/foo.o -a usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.202 MB perf.data ] # perf evlist -v /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # Signed-off-by: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1444826502-49291-6-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 22 ++++++++++++++++++++++ tools/perf/util/bpf-loader.h | 11 +++++++++++ tools/perf/util/parse-events.c | 6 ++++++ 3 files changed, 39 insertions(+) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 56f6fe8cf318..727955858d00 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -243,6 +243,18 @@ int bpf__unprobe(struct bpf_object *obj) 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; +} + #define bpf__strerror_head(err, buf, size) \ char sbuf[STRERR_BUFSIZE], *emsg;\ if (!size)\ @@ -275,3 +287,13 @@ int bpf__strerror_probe(struct bpf_object *obj __maybe_unused, 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; +} diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h index b819622dc7ce..b091ceb19c48 100644 --- a/tools/perf/util/bpf-loader.h +++ b/tools/perf/util/bpf-loader.h @@ -23,6 +23,9 @@ int bpf__unprobe(struct bpf_object *obj); int bpf__strerror_probe(struct bpf_object *obj, int err, char *buf, size_t size); +int bpf__load(struct bpf_object *obj); +int bpf__strerror_load(struct bpf_object *obj, int err, + char *buf, size_t size); #else static inline struct bpf_object * bpf__prepare_load(const char *filename __maybe_unused) @@ -35,6 +38,7 @@ static inline void bpf__clear(void) { } static inline int bpf__probe(struct bpf_object *obj __maybe_unused) { return 0;} static inline int bpf__unprobe(struct bpf_object *obj __maybe_unused) { return 0;} +static inline int bpf__load(struct bpf_object *obj __maybe_unused) { return 0; } static inline int __bpf_strerror(char *buf, size_t size) @@ -55,5 +59,12 @@ bpf__strerror_probe(struct bpf_object *obj __maybe_unused, { return __bpf_strerror(buf, size); } + +static inline int bpf__strerror_load(struct bpf_object *obj __maybe_unused, + int err __maybe_unused, + char *buf, size_t size) +{ + return __bpf_strerror(buf, size); +} #endif #endif diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 10a946779f46..c3aabeb63e88 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -561,6 +561,12 @@ int parse_events_load_bpf_obj(struct parse_events_evlist *data, goto errout; } + err = bpf__load(obj); + if (err) { + bpf__strerror_load(obj, err, errbuf, sizeof(errbuf)); + goto errout; + } + /* * Temporary add a dummy event here so we can check whether * basic bpf loader works. Following patches will replace