diff options
Diffstat (limited to 'arch/x86_64/kernel')
| -rw-r--r-- | arch/x86_64/kernel/apic.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c index e5b14c57eaa0..d54620147e8e 100644 --- a/arch/x86_64/kernel/apic.c +++ b/arch/x86_64/kernel/apic.c @@ -342,6 +342,7 @@ void __init init_bsp_APIC(void) void __cpuinit setup_local_APIC (void) { unsigned int value, maxlvt; + int i, j; value = apic_read(APIC_LVR); @@ -371,6 +372,25 @@ void __cpuinit setup_local_APIC (void) apic_write(APIC_TASKPRI, value); /* + * After a crash, we no longer service the interrupts and a pending + * interrupt from previous kernel might still have ISR bit set. + * + * Most probably by now CPU has serviced that pending interrupt and + * it might not have done the ack_APIC_irq() because it thought, + * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it + * does not clear the ISR bit and cpu thinks it has already serivced + * the interrupt. Hence a vector might get locked. It was noticed + * for timer irq (vector 0x31). Issue an extra EOI to clear ISR. + */ + for (i = APIC_ISR_NR - 1; i >= 0; i--) { + value = apic_read(APIC_ISR + i*0x10); + for (j = 31; j >= 0; j--) { + if (value & (1<<j)) + ack_APIC_irq(); + } + } + + /* * Now that we are all set up, enable the APIC */ value = apic_read(APIC_SPIV); |