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

From: Namhyung Kim
Date: Tue Jun 20 2023 - 16:19:13 EST


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@xxxxxxxxxx>
---
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