From 48957155f8791964d8567479e6986f88343aba38 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 27 Apr 2011 10:31:51 +0100 Subject: [PATCH] ARM: perf: only register a CPU PMU when present Currently, an "empty" struct pmu is registered as the CPU PMU, regardless of whether there is a physical PMU. This burdens the accessor functions with checks to see whether a PMU is actually present. This patch changes initialisation to register a PMU only if there is a supported PMU present, and removes the checks that this change makes redundant. Signed-off-by: Mark Rutland Reviewed-by: Will Deacon Reviewed-by: Jamie Iles Reviewed-by: Ashwin Chaugule Signed-off-by: Will Deacon --- arch/arm/kernel/perf_event.c | 18 ++---------------- 1 file changed, 2 insertions(+), 16 deletions(-) diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 5d60c9c25964..753648cf9af6 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -250,9 +250,6 @@ armpmu_stop(struct perf_event *event, int flags) { struct hw_perf_event *hwc = &event->hw; - if (!armpmu) - return; - /* * ARM pmu always has to update the counter, so ignore * PERF_EF_UPDATE, see comments in armpmu_start(). @@ -270,9 +267,6 @@ armpmu_start(struct perf_event *event, int flags) { struct hw_perf_event *hwc = &event->hw; - if (!armpmu) - return; - /* * ARM pmu always has to reprogram the period, so ignore * PERF_EF_RELOAD, see the comment below. @@ -567,9 +561,6 @@ static int armpmu_event_init(struct perf_event *event) return -ENOENT; } - if (!armpmu) - return -ENODEV; - event->destroy = hw_perf_event_destroy; if (!atomic_inc_not_zero(&active_events)) { @@ -599,9 +590,6 @@ static void armpmu_enable(struct pmu *pmu) int idx, enabled = 0; struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - if (!armpmu) - return; - for (idx = 0; idx < armpmu->num_events; ++idx) { struct perf_event *event = cpuc->events[idx]; @@ -618,8 +606,7 @@ static void armpmu_enable(struct pmu *pmu) static void armpmu_disable(struct pmu *pmu) { - if (armpmu) - armpmu->stop(); + armpmu->stop(); } static struct pmu pmu = { @@ -738,12 +725,11 @@ init_hw_perf_events(void) if (armpmu) { pr_info("enabled with %s PMU driver, %d counters available\n", armpmu->name, armpmu->num_events); + perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW); } else { pr_info("no hardware support available\n"); } - perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW); - return 0; } early_initcall(init_hw_perf_events); -- 2.20.1