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authorTiejun Chen <tiejun.chen@windriver.com>2013-01-15 21:01:19 +0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-01-29 03:18:16 +0400
commit689dfa894c57842a05bf6dc9f97e6bb71ec5f386 (patch)
tree36b1b888f77c68447b57d6db37cafe3032874f31
parentfefd9e6f8860249b2c284d89cb2e51fa71a9503a (diff)
downloadlinux-689dfa894c57842a05bf6dc9f97e6bb71ec5f386.tar.xz
powerpc: Max next_tb to prevent from replaying timer interrupt
With lazy interrupt, we always call __check_irq_replaysome with decrementers_next_tb to check if we need to replay timer interrupt. So in hotplug case we also need to set decrementers_next_tb as MAX to make sure __check_irq_replay don't replay timer interrupt when return as we expect, otherwise we'll trap here infinitely. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/kernel/time.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 6f6b1cccc916..127361e093f4 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -494,10 +494,15 @@ void timer_interrupt(struct pt_regs * regs)
set_dec(DECREMENTER_MAX);
/* Some implementations of hotplug will get timer interrupts while
- * offline, just ignore these
+ * offline, just ignore these and we also need to set
+ * decrementers_next_tb as MAX to make sure __check_irq_replay
+ * don't replay timer interrupt when return, otherwise we'll trap
+ * here infinitely :(
*/
- if (!cpu_online(smp_processor_id()))
+ if (!cpu_online(smp_processor_id())) {
+ *next_tb = ~(u64)0;
return;
+ }
/* Conditionally hard-enable interrupts now that the DEC has been
* bumped to its maximum value