From: Wang Nan <[email protected]>
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 [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]
-e, --event <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 <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Ahern <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kaixu Xia <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
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
--
2.1.0
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