context_tracking: User/kernel broundary cross trace events

This can be useful to track all kernel/user round trips.
And it's also helpful to debug the context tracking subsystem.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index c17822673c39..247091bf0587 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -20,6 +20,9 @@
 #include <linux/hardirq.h>
 #include <linux/export.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/context_tracking.h>
+
 struct static_key context_tracking_enabled = STATIC_KEY_INIT_FALSE;
 EXPORT_SYMBOL_GPL(context_tracking_enabled);
 
@@ -64,6 +67,7 @@ void context_tracking_user_enter(void)
         local_irq_save(flags);
         if ( __this_cpu_read(context_tracking.state) != IN_USER) {
                 if (__this_cpu_read(context_tracking.active)) {
+                        trace_user_enter(0);
                         /*
                          * At this stage, only low level arch entry code remains and
                          * then we'll run in userspace. We can assume there won't be
@@ -159,6 +163,7 @@ void context_tracking_user_exit(void)
                          */
                         rcu_user_exit();
                         vtime_user_exit(current);
+                        trace_user_exit(0);
                 }
                 __this_cpu_write(context_tracking.state, IN_KERNEL);
         }