From 382b9efb7be2d07e51f0a491ecd0a985e1ceb86e Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 28 Jun 2013 18:15:14 +1000 Subject: [PATCH] powerpc/perf: Don't enable if we have zero events commit 4ea355b5368bde0574c12430df53334c4be3bdcf upstream. In power_pmu_enable() we still enable the PMU even if we have zero events. This should have no effect but doesn't make much sense. Instead just return after telling the hypervisor that we are not using the PMCs. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/perf/core-book3s.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index af4b4b1a691f..d3ee2e50a3a6 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -926,6 +926,11 @@ static void power_pmu_enable(struct pmu *pmu) if (!cpuhw->disabled) goto out; + if (cpuhw->n_events == 0) { + ppc_set_pmu_inuse(0); + goto out; + } + cpuhw->disabled = 0; /* @@ -937,8 +942,6 @@ static void power_pmu_enable(struct pmu *pmu) if (!cpuhw->n_added) { mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE); mtspr(SPRN_MMCR1, cpuhw->mmcr[1]); - if (cpuhw->n_events == 0) - ppc_set_pmu_inuse(0); goto out_enable; } -- 2.34.1