the pending interrupt check code is mixed with the local APIC setup code,
that looks messy.
Extract the related code, move it into a new function named
apic_pending_intr_clear().
bonus cleanups from Andy Shevchenko's suggestions:
- for() -> for_each_set_bit()
- printk() -> pr_err()
Signed-off-by: Dou Liyang <douly.f...@cn.fujitsu.com>
---
changlog:
v1 --> v2:
-do some cleanup suggested by Andy
-rebase the patch on the tip/master tree
arch/x86/kernel/apic/apic.c | 99 ++++++++++++++++++++++++---------------------
1 file changed, 53 insertions(+), 46 deletions(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 84b244ec49ed..687457d9df41 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1408,6 +1408,57 @@ static void lapic_setup_esr(void)
oldvalue, value);
}
+static void apic_pending_intr_clear(void)
+{
+ long long max_loops = cpu_khz ? cpu_khz : 1000000;
+ unsigned long long tsc = 0, ntsc;
+ unsigned int queued;
+ unsigned long value;
+ int i, j, acked = 0;
+
+ if (boot_cpu_has(X86_FEATURE_TSC))
+ tsc = rdtsc();
+ /*
+ * 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.
+ */
+ do {
+ queued = 0;
+ for (i = APIC_ISR_NR - 1; i >= 0; i--)
+ queued |= apic_read(APIC_IRR + i*0x10);
+
+ for (i = APIC_ISR_NR - 1; i >= 0; i--) {
+ value = apic_read(APIC_ISR + i*0x10);
+ for_each_set_bit(j, &value, 32) {
+ if (j) {
+ ack_APIC_irq();
+ acked++;
+ }
+ }
+ }
+ if (acked > 256) {
+ pr_err("LAPIC pending interrupts after %d EOI\n",
+ acked);
+ break;
+ }
+ if (queued) {
+ if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
+ ntsc = rdtsc();
+ max_loops = (cpu_khz << 10) - (ntsc - tsc);
+ } else
+ max_loops--;
+ }
+ } while (queued && max_loops > 0);
+ WARN_ON(max_loops <= 0);
+}
+
/**
* setup_local_APIC - setup the local APIC
*
@@ -1417,13 +1468,7 @@ static void lapic_setup_esr(void)
static void setup_local_APIC(void)
{
int cpu = smp_processor_id();
- unsigned int value, queued;
- int i, j, acked = 0;
- unsigned long long tsc = 0, ntsc;
- long long max_loops = cpu_khz ? cpu_khz : 1000000;
-
- if (boot_cpu_has(X86_FEATURE_TSC))
- tsc = rdtsc();
+ unsigned int value;
if (disable_apic) {
disable_ioapic_support();
@@ -1475,45 +1520,7 @@ static void setup_local_APIC(void)
value &= ~APIC_TPRI_MASK;
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.
- */
- do {
- queued = 0;
- for (i = APIC_ISR_NR - 1; i >= 0; i--)
- queued |= apic_read(APIC_IRR + i*0x10);
-
- 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();
- acked++;
- }
- }
- }
- if (acked > 256) {
- printk(KERN_ERR "LAPIC pending interrupts after %d
EOI\n",
- acked);
- break;
- }
- if (queued) {
- if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
- ntsc = rdtsc();
- max_loops = (cpu_khz << 10) - (ntsc - tsc);
- } else
- max_loops--;
- }
- } while (queued && max_loops > 0);
- WARN_ON(max_loops <= 0);
+ apic_pending_intr_clear();
/*
* Now that we are all set up, enable the APIC
--
2.14.3
