tracing: Allow syscall trace events for non privileged users

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>

3 files changed, 13 insertions, 8 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 312dce7e0d52..725bf6bd39f7 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 cacc27a0e285..13b9731d30cf 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 6f540123d43e..e718a917d897 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)