aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/include/asm/hw_irq.h
diff options
context:
space:
mode:
authorPaul Mackerras <paulus@samba.org>2010-04-13 20:46:04 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-05-12 14:34:00 +1000
commit0fe1ac48bef018bed896307cd12f6ca9b5e704ab (patch)
tree6f5e68619798312ee808f23c1a0cc5799a131545 /arch/powerpc/include/asm/hw_irq.h
parentcea0d767c29669bf89f86e4aee46ef462d2ebae8 (diff)
downloadlinaro-lsk-0fe1ac48bef018bed896307cd12f6ca9b5e704ab.tar.gz
powerpc/perf_event: Fix oops due to perf_event_do_pending call
Anton Blanchard found that large POWER systems would occasionally crash in the exception exit path when profiling with perf_events. The symptom was that an interrupt would occur late in the exit path when the MSR[RI] (recoverable interrupt) bit was clear. Interrupts should be hard-disabled at this point but they were enabled. Because the interrupt was not recoverable the system panicked. The reason is that the exception exit path was calling perf_event_do_pending after hard-disabling interrupts, and perf_event_do_pending will re-enable interrupts. The simplest and cleanest fix for this is to use the same mechanism that 32-bit powerpc does, namely to cause a self-IPI by setting the decrementer to 1. This means we can remove the tests in the exception exit path and raw_local_irq_restore. This also makes sure that the call to perf_event_do_pending from timer_interrupt() happens within irq_enter/irq_exit. (Note that calling perf_event_do_pending from timer_interrupt does not mean that there is a possible 1/HZ latency; setting the decrementer to 1 ensures that the timer interrupt will happen immediately, i.e. within one timebase tick, which is a few nanoseconds or 10s of nanoseconds.) Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: stable@kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include/asm/hw_irq.h')
-rw-r--r--arch/powerpc/include/asm/hw_irq.h38
1 files changed, 0 insertions, 38 deletions
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 9f4c9d4f580..bd100fcf40d 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -130,43 +130,5 @@ static inline int irqs_disabled_flags(unsigned long flags)
*/
struct irq_chip;
-#ifdef CONFIG_PERF_EVENTS
-
-#ifdef CONFIG_PPC64
-static inline unsigned long test_perf_event_pending(void)
-{
- unsigned long x;
-
- asm volatile("lbz %0,%1(13)"
- : "=r" (x)
- : "i" (offsetof(struct paca_struct, perf_event_pending)));
- return x;
-}
-
-static inline void set_perf_event_pending(void)
-{
- asm volatile("stb %0,%1(13)" : :
- "r" (1),
- "i" (offsetof(struct paca_struct, perf_event_pending)));
-}
-
-static inline void clear_perf_event_pending(void)
-{
- asm volatile("stb %0,%1(13)" : :
- "r" (0),
- "i" (offsetof(struct paca_struct, perf_event_pending)));
-}
-#endif /* CONFIG_PPC64 */
-
-#else /* CONFIG_PERF_EVENTS */
-
-static inline unsigned long test_perf_event_pending(void)
-{
- return 0;
-}
-
-static inline void clear_perf_event_pending(void) {}
-#endif /* CONFIG_PERF_EVENTS */
-
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_HW_IRQ_H */