tracing: New macro to set up initial event flags value

This introduces the new TRACE_EVENT_FLAGS() macro in order
to set up initial event flags value.

This macro must simply follow the definition of a trace event
and take the event name and the flag value as parameters:

TRACE_EVENT(my_event, .....
....
);

TRACE_EVENT_FLAGS(my_event, 1)

This will set up 1 as the initial my_event->flags value.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>

include/linux/tracepoint.h

@@ -234,6 +234,8 @@ do_trace:								\
 				PARAMS(void *__data, proto),		\
 				PARAMS(__data, args))
 
+#define TRACE_EVENT_FLAGS(event, flag)
+
 #endif /* DECLARE_TRACE */
 
 #ifndef TRACE_EVENT
@@ -354,4 +356,6 @@ do_trace:								\
 		assign, print, reg, unreg)			\
 	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 
+#define TRACE_EVENT_FLAGS(event, flag)
+
 #endif /* ifdef TRACE_EVENT (see note above) */

include/trace/ftrace.h

@@ -82,6 +82,15 @@
 	TRACE_EVENT(name, PARAMS(proto), PARAMS(args),			\
 		PARAMS(tstruct), PARAMS(assign), PARAMS(print))		\
 
+#undef TRACE_EVENT_FLAGS
+#define TRACE_EVENT_FLAGS(name, value)					\
+	static int __init trace_init_flags_##name(void)			\
+	{								\
+		event_##name.flags = value;				\
+		return 0;						\
+	}								\
+	early_initcall(trace_init_flags_##name);
+
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
 
@@ -129,6 +138,9 @@
 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
 	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
 
+#undef TRACE_EVENT_FLAGS
+#define TRACE_EVENT_FLAGS(event, flag)
+
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
 /*