From 79a4cb28a07c4e24103d00741a3dc2618532efe6 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 23 Jul 2014 21:12:36 +1000 Subject: [PATCH] powerpc/perf: Clear all MMCR settings before calling compute_mmcr() Because we reuse cpuhw->mmcr on each call to compute_mmcr() there's a risk that we could forget to set one of the values and use whatever value was in there previously. Currently all the implementations are careful to set all the values, but it's safer to clear them all before we call compute_mmcr(). Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/perf/core-book3s.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index fe52db2eea6a..f82c0973866f 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1219,8 +1219,10 @@ static void power_pmu_enable(struct pmu *pmu) } /* - * Compute MMCR* values for the new set of events + * Clear all MMCR settings and recompute them for the new set of events. */ + memset(cpuhw->mmcr, 0, sizeof(cpuhw->mmcr)); + if (ppmu->compute_mmcr(cpuhw->events, cpuhw->n_events, hwc_index, cpuhw->mmcr)) { /* shouldn't ever get here */ -- 2.30.2