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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04F08C433FE for ; Wed, 30 Nov 2022 15:37:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229926AbiK3PhR (ORCPT ); Wed, 30 Nov 2022 10:37:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229601AbiK3Pgr (ORCPT ); Wed, 30 Nov 2022 10:36:47 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C7FA51C43D for ; Wed, 30 Nov 2022 07:36:45 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 30EE4D6E; Wed, 30 Nov 2022 07:36:52 -0800 (PST) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C77E33F67D; Wed, 30 Nov 2022 07:36:44 -0800 (PST) From: Robin Murphy To: will@kernel.org, mark.rutland@arm.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Geoff Blake Subject: [PATCH 1/2] perf/arm-cmn: Cope with spurious IRQs better Date: Wed, 30 Nov 2022 15:36:38 +0000 Message-Id: X-Mailer: git-send-email 2.36.1.dirty MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Although we reset the CMN state during probe before requesting our interrupt(s), a pending IRQ could already have been latched at the interrupt controller, and thus be delivered spuriously as soon as the IRQ is enabled. Not handling that can then lead to the IRQ layer disabling it again, and things subseuqently going wonky. Since we can't support shared IRQs anyway for affinity-management reasons, the only time we should concievably return IRQ_NONE is for a spurious interrupt which did somehow originate from our CMN, so there should be no harm in removing the problem by simply claiming to have handled those as well. Reported-by: Geoff Blake Signed-off-by: Robin Murphy --- drivers/perf/arm-cmn.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index b80a9b74662b..9e8be5586423 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -1798,7 +1798,6 @@ static int arm_cmn_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_no static irqreturn_t arm_cmn_handle_irq(int irq, void *dev_id) { struct arm_cmn_dtc *dtc = dev_id; - irqreturn_t ret = IRQ_NONE; for (;;) { u32 status = readl_relaxed(dtc->base + CMN_DT_PMOVSR); @@ -1807,7 +1806,6 @@ static irqreturn_t arm_cmn_handle_irq(int irq, void *dev_id) for (i = 0; i < CMN_DTM_NUM_COUNTERS; i++) { if (status & (1U << i)) { - ret = IRQ_HANDLED; if (WARN_ON(!dtc->counters[i])) continue; delta = (u64)arm_cmn_read_counter(dtc, i) << 16; @@ -1816,7 +1814,6 @@ static irqreturn_t arm_cmn_handle_irq(int irq, void *dev_id) } if (status & (1U << CMN_DT_NUM_COUNTERS)) { - ret = IRQ_HANDLED; if (dtc->cc_active && !WARN_ON(!dtc->cycles)) { delta = arm_cmn_read_cc(dtc); local64_add(delta, &dtc->cycles->count); @@ -1826,7 +1823,7 @@ static irqreturn_t arm_cmn_handle_irq(int irq, void *dev_id) writel_relaxed(status, dtc->base + CMN_DT_PMOVSR_CLR); if (!dtc->irq_friend) - return ret; + return IRQ_HANDLED; dtc += dtc->irq_friend; } } -- 2.36.1.dirty