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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 4C6C3C433E6 for ; Tue, 1 Sep 2020 15:48:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C3042064B for ; Tue, 1 Sep 2020 15:48:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598975333; bh=px4bCdgldJNN2SrLtBSSsGhmQR2maebJ4rb7YVyyUBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Zvymoh5NHOXfV3ClFeLrBiX+frg7gqV15mzb1RrG6g1iZjy4uGPHm2K1E4ImmQczE qriQaJAN/88TjSCLa2OaPZg6d/XX4ZcGQN6kdYnXedZxPFWx3vkZsLfYbS2m93K6Yh wap38dAFcS+FvHsxsLDtnIhxm6yHWcl+yGtNz+lU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731838AbgIAPsq (ORCPT ); Tue, 1 Sep 2020 11:48:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:60868 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731582AbgIAPoz (ORCPT ); Tue, 1 Sep 2020 11:44:55 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7F07D2078B; Tue, 1 Sep 2020 15:44:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598975095; bh=px4bCdgldJNN2SrLtBSSsGhmQR2maebJ4rb7YVyyUBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AshxspGXOphG+4c5A4bdiEN97TKVN75+DX5hVOjThi2IQomLa+wCxFBpfi69EIfed NeSPp0c+ehHxlyGv324jKEtht/Gq9ITewrTT48+NHSVoQSk/j9rI8sGbQSMD0EsWkv AFrdIuRWrIjTtuo8Wffa5vEbwmiYh8OhdkGh+nVI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, qiuguorui1 , Marc Zyngier Subject: [PATCH 5.8 207/255] irqchip/stm32-exti: Avoid losing interrupts due to clearing pending bits by mistake Date: Tue, 1 Sep 2020 17:11:03 +0200 Message-Id: <20200901151010.618387021@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901151000.800754757@linuxfoundation.org> References: <20200901151000.800754757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: qiuguorui1 commit e579076ac0a3bebb440fab101aef3c42c9f4c709 upstream. In the current code, when the eoi callback of the exti clears the pending bit of the current interrupt, it will first read the values of fpr and rpr, then logically OR the corresponding bit of the interrupt number, and finally write back to fpr and rpr. We found through experiments that if two exti interrupts, we call them int1/int2, arrive almost at the same time. in our scenario, the time difference is 30 microseconds, assuming int1 is triggered first. there will be an extreme scenario: both int's pending bit are set to 1, the irq handle of int1 is executed first, and eoi handle is then executed, at this moment, all pending bits are cleared, but the int 2 has not finally been reported to the cpu yet, which eventually lost int2. According to stm32's TRM description about rpr and fpr: Writing a 1 to this bit will trigger a rising edge event on event x, Writing 0 has no effect. Therefore, when clearing the pending bit, we only need to clear the pending bit of the irq. Fixes: 927abfc4461e7 ("irqchip/stm32: Add stm32mp1 support with hierarchy domain") Signed-off-by: qiuguorui1 Signed-off-by: Marc Zyngier Cc: stable@vger.kernel.org # v4.18+ Link: https://lore.kernel.org/r/20200820031629.15582-1-qiuguorui1@huawei.com Signed-off-by: Greg Kroah-Hartman --- drivers/irqchip/irq-stm32-exti.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/drivers/irqchip/irq-stm32-exti.c +++ b/drivers/irqchip/irq-stm32-exti.c @@ -431,6 +431,16 @@ static void stm32_irq_ack(struct irq_dat irq_gc_unlock(gc); } +/* directly set the target bit without reading first. */ +static inline void stm32_exti_write_bit(struct irq_data *d, u32 reg) +{ + struct stm32_exti_chip_data *chip_data = irq_data_get_irq_chip_data(d); + void __iomem *base = chip_data->host_data->base; + u32 val = BIT(d->hwirq % IRQS_PER_BANK); + + writel_relaxed(val, base + reg); +} + static inline u32 stm32_exti_set_bit(struct irq_data *d, u32 reg) { struct stm32_exti_chip_data *chip_data = irq_data_get_irq_chip_data(d); @@ -464,9 +474,9 @@ static void stm32_exti_h_eoi(struct irq_ raw_spin_lock(&chip_data->rlock); - stm32_exti_set_bit(d, stm32_bank->rpr_ofst); + stm32_exti_write_bit(d, stm32_bank->rpr_ofst); if (stm32_bank->fpr_ofst != UNDEF_REG) - stm32_exti_set_bit(d, stm32_bank->fpr_ofst); + stm32_exti_write_bit(d, stm32_bank->fpr_ofst); raw_spin_unlock(&chip_data->rlock);