[RFC PATCH v2 14/15] tracing: of: Add function tracer filter properties

Masami Hiramatsu
2019-07-15T05:13:46Z

Add function tracer filter properties which includes
- ftrace-filters : string array of filter rules
- ftrace-notraces : string array of notrace rules
These properties are available on ftrace root node and
instance node.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/trace/trace_of.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)

diff --git a/kernel/trace/trace_of.c b/kernel/trace/trace_of.c
index 14d6c9a8fd81..1ee6fab918f5 100644
--- a/kernel/trace/trace_of.c
+++ b/kernel/trace/trace_of.c
@@ -322,11 +322,47 @@ trace_of_init_events(struct trace_array *tr, struct device_node *node)
#define trace_of_init_events(tr, node) do {} while (0)
#endif

+#ifdef CONFIG_FUNCTION_TRACER
+extern bool ftrace_filter_param __initdata;
+extern int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+ int len, int reset);
+extern int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+ int len, int reset);
+
+static void __init
+trace_of_set_ftrace_filter(struct ftrace_ops *ops, const char *property,
+ struct device_node *node)
+{
+ struct property *prop;
+ const char *p;
+ char buf[MAX_BUF_LEN];
+ int err;
+
+ of_property_for_each_string(node, property, prop, p) {
+ if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
+ pr_err("filter string is too long: %s\n", p);
+ return;
+ }
+ err = ftrace_set_filter(ops, buf, strlen(buf), 0);
+ if (err) {
+ pr_err("Failed to add %s: %s\n", property, buf);
+ return;
+ }
+ ftrace_filter_param = true;
+ }
+}
+#else
+#define trace_of_set_ftrace_filter(ops, prop, node) do {} while (0)
+#endif
+
static void __init
trace_of_enable_tracer(struct trace_array *tr, struct device_node *node)
{
const char *p;

+ trace_of_set_ftrace_filter(tr->ops, "ftrace-filters", node);
+ trace_of_set_ftrace_filter(tr->ops, "ftrace-notraces", node);
+
if (!of_property_read_string(node, "tracer", &p)) {
if (tracing_set_tracer(tr, p) < 0)
pr_err("Failed to set given tracer: %s\n", p);