[PATCH 04/13] perf tools: Allow BPF program attach to modules

From: Wang Nan
Date: Mon Nov 16 2015 - 07:49:32 EST


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

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

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

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kaixu Xia <xiakaixu@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/1445915248-175553-1-git-send-email-wangnan0@xxxxxxxxxx
---
tools/perf/util/bpf-loader.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 54bfe62..aeac08c 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
--
1.8.3.4

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