Re: [PATCH 04/12] perf tools: Allow BPF program attach to modules

From: Arnaldo Carvalho de Melo
Date: Fri Nov 13 2015 - 10:40:24 EST


Em Fri, Nov 13, 2015 at 12:29:13PM +0000, Wang Nan escreveu:
> 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 | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
> index 5f5505d..8d78785 100644
> --- a/tools/perf/util/bpf-loader.c
> +++ b/tools/perf/util/bpf-loader.c
> @@ -117,6 +117,14 @@ 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);
> + return 0;
> +}

check strdup return

> +
> static struct {
> const char *key;
> const char *usage;
> @@ -129,6 +137,12 @@ static struct {
> "Set uprobe target",
> config__exec,
> },
> + {
> + "module",
> + "module=<module name> ",
> + "Set kprobe module",
> + config__module,
> + }

Named initializers, please.

> };
>
> static int
> --
> 1.8.3.4
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