From e04ed38d4e0cd32141f723560efcc8252b0241e2 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 4 Jan 2010 23:16:03 -0800 Subject: [PATCH] sparc64: Fix Niagara2 perf event handling. For chips like Niagara2 that have true overflow indications in the %pcr (which we don't actually need and don't use) the interrupt signal persists until the overflow bits are cleared by an explicit %pcr write. Signed-off-by: David S. Miller --- arch/sparc/kernel/perf_event.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index fa5936e1c3b9..198fb4e79ba2 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -986,6 +986,17 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self, data.addr = 0; cpuc = &__get_cpu_var(cpu_hw_events); + + /* If the PMU has the TOE IRQ enable bits, we need to do a + * dummy write to the %pcr to clear the overflow bits and thus + * the interrupt. + * + * Do this before we peek at the counters to determine + * overflow so we don't lose any events. + */ + if (sparc_pmu->irq_bit) + pcr_ops->write(cpuc->pcr); + for (idx = 0; idx < MAX_HWEVENTS; idx++) { struct perf_event *event = cpuc->events[idx]; struct hw_perf_event *hwc; -- 2.20.1