From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B1C0C5CFC1 for ; Tue, 19 Jun 2018 10:16:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E1E820836 for ; Tue, 19 Jun 2018 10:16:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E1E820836 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937589AbeFSKQT (ORCPT ); Tue, 19 Jun 2018 06:16:19 -0400 Received: from foss.arm.com ([217.140.101.70]:46652 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937571AbeFSKQQ (ORCPT ); Tue, 19 Jun 2018 06:16:16 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EEF171682; Tue, 19 Jun 2018 03:16:15 -0700 (PDT) Received: from en101.cambridge.arm.com (en101.cambridge.arm.com [10.1.206.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9B6513F25D; Tue, 19 Jun 2018 03:16:14 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: mark.rutland@arm.com, linux-kernel@vger.kernel.org, will.deacon@arm.com, robin.murphy@arm.com, julien.thierry@arm.com, Suzuki K Poulose Subject: [PATCH v3 6/7] arm64: perf: Disable PMU while processing counter overflows Date: Tue, 19 Jun 2018 11:15:41 +0100 Message-Id: <1529403342-17899-7-git-send-email-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1529403342-17899-1-git-send-email-suzuki.poulose@arm.com> References: <1529403342-17899-1-git-send-email-suzuki.poulose@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The arm64 PMU updates the event counters and reprograms the counters in the overflow IRQ handler without disabling the PMU. This could potentially cause skews in for group counters, where the overflowed counters may potentially loose some event counts, while they are reprogrammed. To prevent this, disable the PMU while we process the counter overflows and enable it right back when we are done. This patch also moves the PMU stop/start routines to avoid a forward declaration. Suggested-by: Mark Rutland Cc: Will Deacon Signed-off-by: Suzuki K Poulose --- arch/arm64/kernel/perf_event.c | 50 +++++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 22 deletions(-) diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 9ce3729..eebc635 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -678,6 +678,28 @@ static void armv8pmu_disable_event(struct perf_event *event) raw_spin_unlock_irqrestore(&events->pmu_lock, flags); } +static void armv8pmu_start(struct arm_pmu *cpu_pmu) +{ + unsigned long flags; + struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events); + + raw_spin_lock_irqsave(&events->pmu_lock, flags); + /* Enable all counters */ + armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E); + raw_spin_unlock_irqrestore(&events->pmu_lock, flags); +} + +static void armv8pmu_stop(struct arm_pmu *cpu_pmu) +{ + unsigned long flags; + struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events); + + raw_spin_lock_irqsave(&events->pmu_lock, flags); + /* Disable all counters */ + armv8pmu_pmcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_PMCR_E); + raw_spin_unlock_irqrestore(&events->pmu_lock, flags); +} + static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) { u32 pmovsr; @@ -702,6 +724,11 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) */ regs = get_irq_regs(); + /* + * Stop the PMU while processing the counter overflows + * to prevent skews in group events. + */ + armv8pmu_stop(cpu_pmu); for (idx = 0; idx < cpu_pmu->num_events; ++idx) { struct perf_event *event = cpuc->events[idx]; struct hw_perf_event *hwc; @@ -726,6 +753,7 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) if (perf_event_overflow(event, &data, regs)) cpu_pmu->disable(event); } + armv8pmu_start(cpu_pmu); /* * Handle the pending perf events. @@ -739,28 +767,6 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) return IRQ_HANDLED; } -static void armv8pmu_start(struct arm_pmu *cpu_pmu) -{ - unsigned long flags; - struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events); - - raw_spin_lock_irqsave(&events->pmu_lock, flags); - /* Enable all counters */ - armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E); - raw_spin_unlock_irqrestore(&events->pmu_lock, flags); -} - -static void armv8pmu_stop(struct arm_pmu *cpu_pmu) -{ - unsigned long flags; - struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events); - - raw_spin_lock_irqsave(&events->pmu_lock, flags); - /* Disable all counters */ - armv8pmu_pmcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_PMCR_E); - raw_spin_unlock_irqrestore(&events->pmu_lock, flags); -} - static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc, struct perf_event *event) { -- 2.7.4