perf bpf: Allow attaching BPF programs to modules symbols

By extending the syntax of BPF object section names, this patch allows
users to attach BPF programs to symbols in modules. For example:

  SEC("module=i915;"
      "parse_cmds=i915_parse_cmds")
  int parse_cmds(void *ctx)
  {
      return 1;
  }

The implementation is very simple: like what 'perf probe' does, for module,
fill 'uprobe' field in 'struct perf_probe_event'. Other parts will be done
automatically.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447675815-166222-5-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 84169d6f2585..d0f02ed93804 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -119,6 +119,16 @@ config__exec(const char *value, struct perf_probe_event *pev)
         return 0;
 }
 
+static int
+config__module(const char *value, struct perf_probe_event *pev)
+{
+        pev->uprobes = false;
+        pev->target = strdup(value);
+        if (!pev->target)
+                return -ENOMEM;
+        return 0;
+}
+
 static struct {
         const char *key;
         const char *usage;
@@ -131,6 +141,12 @@ static struct {
                 .desc   = "Set uprobe target",
                 .func   = config__exec,
         },
+        {
+                .key    = "module",
+                .usage  = "module=<module name>    ",
+                .desc   = "Set kprobe module",
+                .func   = config__module,
+        }
 };
 
 static int