x86/apic: Implement set_state_oneshot_stopped() callback

When clock_event_device::set_state_oneshot_stopped() is not implemented, hrtimer_cancel() can't stop the clock when there is no more timer in the queue. So the ghost of the freshly cancelled hrtimer haunts us back later with an extra interrupt:

          <idle>-0     [002] d..2  2248.557659: hrtimer_cancel: hrtimer=ffff88021fa92d80
          <idle>-0     [002] d.h1  2249.303659: local_timer_entry: vector=239

So let's implement this missing callback for the lapic clock. This consist in calling its set_state_shutdown() callback. There don't seem to be a lighter way to stop the clock. Simply writing 0 to APIC_TMICT won't be enough to stop the clock and avoid the extra interrupt, as opposed to what is specified in the specs. We must also mask the timer interrupt in the device.

Cc Thomas Gleixner <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Wanpeng Li <[email protected]>

Cc Viresh Kumar <[email protected]>

Signed-off-by Frederic Weisbecker <[email protected]>

---

 arch/x86/kernel/apic/apic.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

arch/x86/kernel/apic/apic.c +13 -13

index 5b7e43e..a8e90db 100644
@@ -529,18 +529,19 @@ static void lapic_timer_broadcast(const struct cpumask *mask)
  * The local apic timer can be used for any function which is CPU local.
  */
 static struct clock_event_device lapic_clockevent = {
-       .name                   = "lapic",
-       .features               = CLOCK_EVT_FEAT_PERIODIC |
-                                 CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP
-                                 | CLOCK_EVT_FEAT_DUMMY,
-       .shift                  = 32,
-       .set_state_shutdown     = lapic_timer_shutdown,
-       .set_state_periodic     = lapic_timer_set_periodic,
-       .set_state_oneshot      = lapic_timer_set_oneshot,
-       .set_next_event         = lapic_next_event,
-       .broadcast              = lapic_timer_broadcast,
-       .rating                 = 100,
-       .irq                    = -1,
+       .name                           = "lapic",
+       .features                       = CLOCK_EVT_FEAT_PERIODIC |
+                                         CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP
+                                         | CLOCK_EVT_FEAT_DUMMY,
+       .shift                          = 32,
+       .set_state_shutdown             = lapic_timer_shutdown,
+       .set_state_periodic             = lapic_timer_set_periodic,
+       .set_state_oneshot              = lapic_timer_set_oneshot,
+       .set_state_oneshot_stopped      = lapic_timer_shutdown,
+       .set_next_event                 = lapic_next_event,
+       .broadcast                      = lapic_timer_broadcast,
+       .rating                         = 100,
+       .irq                            = -1,
 };
 static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
 
--

2.7.4

When clock_event_device::set_state_oneshot_stopped() is not implemented, hrtimer_cancel() can't stop the clock when there is no more timer in the queue. So the ghost of the freshly cancelled hrtimer haunts us back later with an extra interrupt:

          <idle>-0     [002] d..2  2248.557659: hrtimer_cancel: hrtimer=ffff88021fa92d80
          <idle>-0     [002] d.h1  2249.303659: local_timer_entry: vector=239

So let's implement this missing callback for the lapic clock. This consist in calling its set_state_shutdown() callback. There don't seem to be a lighter way to stop the clock. Simply writing 0 to APIC_TMICT won't be enough to stop the clock and avoid the extra interrupt, as opposed to what is specified in the specs. We must also mask the timer interrupt in the device.

Cc Thomas Gleixner <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Wanpeng Li <[email protected]>

Cc Viresh Kumar <[email protected]>

Signed-off-by Frederic Weisbecker <[email protected]>

---
 arch/x86/kernel/apic/apic.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)