[PATCH 093/112] ACPI: idle: Fix acpi_safe_halt usages and interrupt enabling/disabling

Len Brown
2008-02-07T09:36:53Z

From: venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>

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>
---
drivers/acpi/processor_idle.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 199ea21..106a229 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;
}
}
--
1.5.4.23.gef5b9