perf ftrace: Add support for tracing option 'irq-info'

This adds support to display irq context info for function tracer. To do
this, just specify a '--func-opts irq-info' option.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-12-changbin.du@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-ftrace.txt

@@ -79,6 +79,7 @@ OPTIONS
 --func-opts::
 	List of options allowed to set:
 	  call-graph - Display kernel stack trace for function tracer.
+	  irq-info   - Display irq context info for function tracer.
 
 -G::
 --graph-funcs=::

tools/perf/builtin-ftrace.c

@@ -44,6 +44,7 @@ struct perf_ftrace {
 	unsigned long		percpu_buffer_size;
 	bool			inherit;
 	int			func_stack_trace;
+	int			func_irq_info;
 	int			graph_nosleep_time;
 	int			graph_noirqs;
 };
@@ -209,6 +210,7 @@ static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
 	write_tracing_option_file("func_stack_trace", "0");
 	write_tracing_option_file("sleep-time", "1");
 	write_tracing_option_file("funcgraph-irqs", "1");
+	write_tracing_option_file("irq-info", "0");
 }
 
 static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
@@ -296,6 +298,17 @@ static int set_tracing_func_stack_trace(struct perf_ftrace *ftrace)
 	return 0;
 }
 
+static int set_tracing_func_irqinfo(struct perf_ftrace *ftrace)
+{
+	if (!ftrace->func_irq_info)
+		return 0;
+
+	if (write_tracing_option_file("irq-info", "1") < 0)
+		return -1;
+
+	return 0;
+}
+
 static int reset_tracing_cpu(void)
 {
 	struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
@@ -471,6 +484,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 		goto out_reset;
 	}
 
+	if (set_tracing_func_irqinfo(ftrace) < 0) {
+		pr_err("failed to set tracing option irq-info\n");
+		goto out_reset;
+	}
+
 	if (set_tracing_filters(ftrace) < 0) {
 		pr_err("failed to set tracing filters\n");
 		goto out_reset;
@@ -660,6 +678,7 @@ static int parse_func_tracer_opts(const struct option *opt,
 	struct perf_ftrace *ftrace = (struct perf_ftrace *) opt->value;
 	struct sublevel_option func_tracer_opts[] = {
 		{ .name = "call-graph",	.value_ptr = &ftrace->func_stack_trace },
+		{ .name = "irq-info",	.value_ptr = &ftrace->func_irq_info },
 		{ .name = NULL, }
 	};
 
@@ -742,7 +761,7 @@ int cmd_ftrace(int argc, const char **argv)
 	OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
 		     "do not trace given functions", parse_filter_func),
 	OPT_CALLBACK(0, "func-opts", &ftrace, "options",
-		     "function tracer options, available options: call-graph",
+		     "function tracer options, available options: call-graph,irq-info",
 		     parse_func_tracer_opts),
 	OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
 		     "trace given functions using function_graph tracer",