ACPI: idle: Fix acpi_safe_halt usages and interrupt enabling/disabling

acpi_safe_halt() needs interrupts to be disabled for atomic
need_resched check and safe halt. Otherwise we may miss an
interrupt and go into halt.

acpi_safe_halt() also does not enable interrupts on all return paths.

So the callers should handle enable and disable interrupts around it.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 199ea2146153..106a22948aa9 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -201,6 +201,10 @@ static inline u32 ticks_elapsed_in_us(u32 t1, u32 t2)
                 return PM_TIMER_TICKS_TO_US((0xFFFFFFFF - t1) + t2);
 }
 
+/*
+ * Callers should disable interrupts before the call and enable
+ * interrupts after return.
+ */
 static void acpi_safe_halt(void)
 {
         current_thread_info()->status &= ~TS_POLLING;
@@ -413,6 +417,8 @@ static void acpi_processor_idle(void)
                         pm_idle_save();
                 else
                         acpi_safe_halt();
+
+                local_irq_enable();
                 return;
         }
 
@@ -521,6 +527,7 @@ static void acpi_processor_idle(void)
                  *       skew otherwise.
                  */
                 sleep_ticks = 0xFFFFFFFF;
+                local_irq_enable();
                 break;
 
         case ACPI_STATE_C2:
@@ -1403,11 +1410,13 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
         if (unlikely(!pr))
                 return 0;
 
+        local_irq_disable();
         if (pr->flags.bm_check)
                 acpi_idle_update_bm_rld(pr, cx);
 
         acpi_safe_halt();
 
+        local_irq_enable();
         cx->usage++;
 
         return 0;
@@ -1517,7 +1526,9 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
                 if (dev->safe_state) {
                         return dev->safe_state->enter(dev, dev->safe_state);
                 } else {
+                        local_irq_disable();
                         acpi_safe_halt();
+                        local_irq_enable();
                         return 0;
                 }
         }