cpuidle: Run tick_broadcast_exit() with disabled interrupts

Commit 335f49196fd6 (sched/idle: Use explicit broadcast oneshot
control function) replaced clockevents_notify() invocations in
cpuidle_idle_call() with direct calls to tick_broadcast_enter()
and tick_broadcast_exit(), but it overlooked the fact that
interrupts were already enabled before calling the latter which
led to functional breakage on systems using idle states with the
CPUIDLE_FLAG_TIMER_STOP flag set.

Fix that by moving the invocations of tick_broadcast_enter()
and tick_broadcast_exit() down into cpuidle_enter_state() where
interrupts are still disabled when tick_broadcast_exit() is
called.  Also ensure that interrupts will be disabled before
running tick_broadcast_exit() even if they have been enabled by
the idle state's ->enter callback.  Trigger a WARN_ON_ONCE() in
that case, as we generally don't want that to happen for states
with CPUIDLE_FLAG_TIMER_STOP set.

Fixes: 335f49196fd6 (sched/idle: Use explicit broadcast oneshot control function)
Reported-and-tested-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 14 deletions

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index deef1caa94c6..fefcb1fa5160 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -81,7 +81,6 @@ static void cpuidle_idle_call(void)
         struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
         struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
         int next_state, entered_state;
-        unsigned int broadcast;
         bool reflect;
 
         /*
@@ -150,17 +149,6 @@ static void cpuidle_idle_call(void)
                 goto exit_idle;
         }
 
-        broadcast = drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP;
-
-        /*
-         * Tell the time framework to switch to a broadcast timer
-         * because our local timer will be shutdown. If a local timer
-         * is used from another cpu as a broadcast timer, this call may
-         * fail if it is not available
-         */
-        if (broadcast && tick_broadcast_enter())
-                goto use_default;
-
         /* Take note of the planned idle state. */
         idle_set_state(this_rq(), &drv->states[next_state]);
 
@@ -174,8 +162,8 @@ static void cpuidle_idle_call(void)
         /* The cpu is no longer idle or about to enter idle. */
         idle_set_state(this_rq(), NULL);
 
-        if (broadcast)
-                tick_broadcast_exit();
+        if (entered_state == -EBUSY)
+                goto use_default;
 
         /*
          * Give the governor an opportunity to reflect on the outcome