cpuidle: move idle traces to cpuidle_enter_state()

idle_exit event is the first event after a core exits
idle state. So this should be traced before local irq
is ebabled. Likewise idle_entry is the last event before
a core enters idle state. This will ease visualising the
cpu idle state from kernel traces.

Signed-off-by: Sandeep Tripathy <sandeep.tripathy@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[rjw: Subject, rebase]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpuidle/cpuidle.c

@@ -119,11 +119,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
 	ktime_t time_start, time_end;
 	s64 diff;
 
+	trace_cpu_idle_rcuidle(index, dev->cpu);
 	time_start = ktime_get();
 
 	entered_state = target_state->enter(dev, drv, index);
 
 	time_end = ktime_get();
+	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
 
 	if (!cpuidle_state_is_coupled(dev, drv, entered_state))
 		local_irq_enable();

kernel/sched/idle.c

@@ -147,17 +147,13 @@ static void cpuidle_idle_call(void)
 	    clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu))
 		goto use_default;
 
-	trace_cpu_idle_rcuidle(next_state, dev->cpu);
-
 	/*
 	 * Enter the idle state previously returned by the governor decision.
 	 * This function will block until an interrupt occurs and will take
 	 * care of re-enabling the local interrupts
 	 */
 	entered_state = cpuidle_enter(drv, dev, next_state);
 
-	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
-
 	if (broadcast)
 		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);