path: root/arch/powerpc/include
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authorAnton Blanchard <anton@samba.org>2011-11-23 20:07:17 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-11-25 14:09:58 +1100
commit37fb9a0231ee43d42d069863bdfd567fca2b61af (patch)
tree37b53a4a591c3e20676809a6f4f6c59ff693f15a /arch/powerpc/include
parentcaca6a03d365883564885f2c1da3e88dcf65d139 (diff)
powerpc/time: Handle wrapping of decrementer
When re-enabling interrupts we have code to handle edge sensitive decrementers by resetting the decrementer to 1 whenever it is negative. If interrupts were disabled long enough that the decrementer wrapped to positive we do nothing. This means interrupts can be delayed for a long time until it finally goes negative again. While we hope interrupts are never be disabled long enough for the decrementer to go positive, we have a very good test team that can drive any kernel into the ground. The softlockup data we get back from these fails could be seconds in the future, completely missing the cause of the lockup. We already keep track of the timebase of the next event so use that to work out if we should trigger a decrementer exception. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: stable@kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include')
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
index fe6f7c2c9c6..bc3c745cb90 100644
--- a/arch/powerpc/include/asm/time.h
+++ b/arch/powerpc/include/asm/time.h
@@ -219,5 +219,7 @@ DECLARE_PER_CPU(struct cpu_usage, cpu_usage_array);
extern void secondary_cpu_time_init(void);
extern void iSeries_time_init_early(void);
+extern void decrementer_check_overflow(void);
#endif /* __KERNEL__ */
#endif /* __POWERPC_TIME_H */