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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-03-28 23:51:10 -0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-04-01 00:37:07 -0400
commit963e5d3b76d657f1ebcf3561446d2ba1872bbfa2 (patch)
tree323acf4be02bddfebc9fe0a415b9e709fb8f5bf5 /arch
parentecb78ab6f30106ab72a575a25b1cdfd1633b7ca2 (diff)
powerpc: Make decrementer interrupt robust against offlined CPUs
With some implementations, it is possible that a timer interrupt occurs every few seconds on an offline CPU. In this case, just re-arm the decrementer and return immediately Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/time.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index aa9269600ca2..375480c56eb9 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -577,14 +577,21 @@ void timer_interrupt(struct pt_regs * regs)
577 struct clock_event_device *evt = &decrementer->event; 577 struct clock_event_device *evt = &decrementer->event;
578 u64 now; 578 u64 now;
579 579
580 /* Ensure a positive value is written to the decrementer, or else
581 * some CPUs will continue to take decrementer exceptions.
582 */
583 set_dec(DECREMENTER_MAX);
584
585 /* Some implementations of hotplug will get timer interrupts while
586 * offline, just ignore these
587 */
588 if (!cpu_online(smp_processor_id()))
589 return;
590
580 trace_timer_interrupt_entry(regs); 591 trace_timer_interrupt_entry(regs);
581 592
582 __get_cpu_var(irq_stat).timer_irqs++; 593 __get_cpu_var(irq_stat).timer_irqs++;
583 594
584 /* Ensure a positive value is written to the decrementer, or else
585 * some CPUs will continuue to take decrementer exceptions */
586 set_dec(DECREMENTER_MAX);
587
588#if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) 595#if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
589 if (atomic_read(&ppc_n_lost_interrupts) != 0) 596 if (atomic_read(&ppc_n_lost_interrupts) != 0)
590 do_IRQ(regs); 597 do_IRQ(regs);