[PATCH 4/5] tracing: Allow syscall trace events for non privileged users

[Frederic Weisbecker <fweisbec@gmail.com>]

As for the raw syscalls events, individual syscall events won't
leak system wide information on task bound tracing. Allow non
privileged users to use them in such workflow.

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/ftrace_event.h |    8 ++++++++
 include/linux/syscalls.h     |    6 ++++--
 include/trace/ftrace.h       |    7 +------
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 312dce7..725bf6b 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -198,6 +198,14 @@ struct ftrace_event_call {
 #endif
 };
 
+#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);
+
 #define PERF_MAX_TRACE_SIZE	2048
 
 #define MAX_FILTER_PRED		32
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index cacc27a..13b9731 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -137,7 +137,8 @@ extern struct trace_event_functions exit_syscall_print_funcs;
 		.class			= &event_class_syscall_enter,	\
 		.event.funcs            = &enter_syscall_print_funcs,	\
 		.data			= (void *)&__syscall_meta_##sname,\
-	}
+	};								\
+	__TRACE_EVENT_FLAGS(enter_##sname, TRACE_EVENT_FL_CAP_ANY)
 
 #define SYSCALL_TRACE_EXIT_EVENT(sname)					\
 	static struct syscall_metadata					\
@@ -152,7 +153,8 @@ extern struct trace_event_functions exit_syscall_print_funcs;
 		.class			= &event_class_syscall_exit,	\
 		.event.funcs		= &exit_syscall_print_funcs,	\
 		.data			= (void *)&__syscall_meta_##sname,\
-	}
+	};								\
+	__TRACE_EVENT_FLAGS(exit_##sname, TRACE_EVENT_FL_CAP_ANY)
 
 #define SYSCALL_METADATA(sname, nb)				\
 	SYSCALL_TRACE_ENTER_EVENT(sname);			\
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 6f54012..e718a91 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -84,12 +84,7 @@
 
 #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);
+	__TRACE_EVENT_FLAGS(name, value)
 
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
-- 
1.6.2.3