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>

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 199ea21..106a229 100644 (file)
--- 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;
                }
        }