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-rw-r--r--arch/i386/kernel/apic.c20
-rw-r--r--include/asm-i386/apicdef.h1
2 files changed, 21 insertions, 0 deletions
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index eb5279d23b7..3fff3c62d57 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -415,6 +415,7 @@ void __init init_bsp_APIC(void)
void __devinit setup_local_APIC(void)
{
unsigned long oldvalue, value, ver, maxlvt;
+ int i, j;
/* Pound the ESR really hard over the head with a big hammer - mbligh */
if (esr_disable) {
@@ -452,6 +453,25 @@ void __devinit setup_local_APIC(void)
apic_write_around(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);
diff --git a/include/asm-i386/apicdef.h b/include/asm-i386/apicdef.h
index 03185cef8e0..5e4a35af292 100644
--- a/include/asm-i386/apicdef.h
+++ b/include/asm-i386/apicdef.h
@@ -37,6 +37,7 @@
#define APIC_SPIV_FOCUS_DISABLED (1<<9)
#define APIC_SPIV_APIC_ENABLED (1<<8)
#define APIC_ISR 0x100
+#define APIC_ISR_NR 0x8 /* Number of 32 bit ISR registers. */
#define APIC_TMR 0x180
#define APIC_IRR 0x200
#define APIC_ESR 0x280