Re: [PATCH 2/3] perf tools: Add kallsyms__get_symbol_start()

[Ian Rogers <irogers@google.com>]

On Tue, Jun 20, 2023 at 1:18 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> The kallsyms__get_symbol_start() to get any symbol address from
> kallsyms.  The existing kallsyms__get_function_start() only allows text
> symbols so create this to allow data symbols too.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/util/event.c | 30 +++++++++++++++++++++++++++---
>  tools/perf/util/event.h |  2 ++
>  2 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> index 3860b0c74829..6fdda0eb3854 100644
> --- a/tools/perf/util/event.c
> +++ b/tools/perf/util/event.c
> @@ -93,8 +93,8 @@ struct process_symbol_args {
>         u64        start;
>  };
>
> -static int find_symbol_cb(void *arg, const char *name, char type,
> -                         u64 start)
> +static int find_func_symbol_cb(void *arg, const char *name, char type,
> +                              u64 start)
>  {
>         struct process_symbol_args *args = arg;
>
> @@ -110,12 +110,36 @@ static int find_symbol_cb(void *arg, const char *name, char type,
>         return 1;
>  }
>
> +static int find_any_symbol_cb(void *arg, const char *name,
> +                             char type __maybe_unused, u64 start)
> +{
> +       struct process_symbol_args *args = arg;
> +
> +       if (strcmp(name, args->name))
> +               return 0;
> +
> +       args->start = start;
> +       return 1;
> +}
> +
>  int kallsyms__get_function_start(const char *kallsyms_filename,
>                                  const char *symbol_name, u64 *addr)
>  {
>         struct process_symbol_args args = { .name = symbol_name, };
>
> -       if (kallsyms__parse(kallsyms_filename, &args, find_symbol_cb) <= 0)
> +       if (kallsyms__parse(kallsyms_filename, &args, find_func_symbol_cb) <= 0)
> +               return -1;
> +
> +       *addr = args.start;
> +       return 0;
> +}
> +
> +int kallsyms__get_symbol_start(const char *kallsyms_filename,
> +                              const char *symbol_name, u64 *addr)
> +{
> +       struct process_symbol_args args = { .name = symbol_name, };
> +
> +       if (kallsyms__parse(kallsyms_filename, &args, find_any_symbol_cb) <= 0)
>                 return -1;
>
>         *addr = args.start;
> diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
> index de20e01c9d72..d8bcee2e9b93 100644
> --- a/tools/perf/util/event.h
> +++ b/tools/perf/util/event.h
> @@ -360,6 +360,8 @@ size_t perf_event__fprintf(union perf_event *event, struct machine *machine, FIL
>
>  int kallsyms__get_function_start(const char *kallsyms_filename,
>                                  const char *symbol_name, u64 *addr);
> +int kallsyms__get_symbol_start(const char *kallsyms_filename,
> +                              const char *symbol_name, u64 *addr);
>
>  void event_attr_init(struct perf_event_attr *attr);
>
> --
> 2.41.0.185.g7c58973941-goog
>