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Subject[PATCH 1/8] x86, apic.c: Disable irq0 if CPU enables ARAT for local apic timer
Date
From: Fenghua Yu <fenghua.yu@intel.com>

irq0 won't generate any interrupt after local apic timers is enabled and ARAT
is enabled. Disable irq0 in this case. Thus irq0 won't block BSP offline.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
arch/x86/kernel/apic/apic.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 52fa563..8813acf 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -506,6 +506,7 @@ static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
static void __cpuinit setup_APIC_timer(void)
{
struct clock_event_device *levt = &__get_cpu_var(lapic_events);
+ int cpu = smp_processor_id();

if (this_cpu_has(X86_FEATURE_ARAT)) {
lapic_clockevent.features &= ~CLOCK_EVT_FEAT_C3STOP;
@@ -517,6 +518,10 @@ static void __cpuinit setup_APIC_timer(void)
levt->cpumask = cpumask_of(smp_processor_id());

clockevents_register_device(levt);
+
+ /* irq0 won't be used any more if CPU supports ARAT feature. */
+ if (cpu == 0 && this_cpu_has(X86_FEATURE_ARAT))
+ disable_irq(0);
}

/*
--
1.6.0.3


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