\
> diff --git a/arch/powerpc/kernel/perf_event.c
> b/arch/powerpc/kernel/perf_event.c
> index 97e0ae4..0a5178f 100644
> --- a/arch/powerpc/kernel/perf_event.c
> +++ b/arch/powerpc/kernel/perf_event.c
> @@ -416,6 +416,15 @@ static void power_pmu_read(struct perf_event *event)
> prev
Because of speculative event roll back, it is possible for some event coutners
to decrease between reads on POWER7. This causes a problem with the way that
counters are updated. Delta calues are calculated in a 64 bit value and the
top 32 bits are masked. If the register value has decreased, thi
