1 files changed, 46 insertions, 0 deletions

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 048a11192b59..1ebf71ecc1a8 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -33,6 +33,7 @@ struct perf_ftrace {
 	struct evlist		*evlist;
 	struct target		target;
 	const char		*tracer;
+	bool			list_avail_functions;
 	struct list_head	filters;
 	struct list_head	notrace;
 	struct list_head	graph_funcs;
@@ -128,6 +129,46 @@ static int append_tracing_file(const char *name, const char *val)
 	return __write_tracing_file(name, val, true);
 }
 
+static int read_tracing_file_to_stdout(const char *name)
+{
+	char buf[4096];
+	char *file;
+	int fd;
+	int ret = -1;
+
+	file = get_tracing_file(name);
+	if (!file) {
+		pr_debug("cannot get tracing file: %s\n", name);
+		return -1;
+	}
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0) {
+		pr_debug("cannot open tracing file: %s: %s\n",
+			 name, str_error_r(errno, buf, sizeof(buf)));
+		goto out;
+	}
+
+	/* read contents to stdout */
+	while (true) {
+		int n = read(fd, buf, sizeof(buf));
+		if (n == 0)
+			break;
+		else if (n < 0)
+			goto out_close;
+
+		if (fwrite(buf, n, 1, stdout) != 1)
+			goto out_close;
+	}
+	ret = 0;
+
+out_close:
+	close(fd);
+out:
+	put_tracing_file(file);
+	return ret;
+}
+
 static int reset_tracing_cpu(void);
 static void reset_tracing_filters(void);
 
@@ -302,6 +343,9 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 	signal(SIGCHLD, sig_handler);
 	signal(SIGPIPE, sig_handler);
 
+	if (ftrace->list_avail_functions)
+		return read_tracing_file_to_stdout("available_filter_functions");
+
 	if (reset_tracing_files(ftrace) < 0) {
 		pr_err("failed to reset ftrace\n");
 		goto out;
@@ -487,6 +531,8 @@ int cmd_ftrace(int argc, const char **argv)
 	const struct option ftrace_options[] = {
 	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
 		   "tracer to use: function_graph(default) or function"),
+	OPT_BOOLEAN('F', "funcs", &ftrace.list_avail_functions,
+		    "Show available functions to filter"),
 	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
 		   "trace on existing process id"),
 	OPT_INCR('v', "verbose", &verbose,