From patchwork Thu May 4 11:35:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AngeloGioacchino Del Regno X-Patchwork-Id: 13231067 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A68FBC7EE21 for ; Thu, 4 May 2023 11:36:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=XanPCdf/QzluUYaXVnffgGHNjdwZdtz7w222UbKmTtw=; b=ILA8dBq3RHVm5T OOuvwp74onrpWhR2YsTH1JFOFVV8BVSC3ytBKe2MaCu+X5MDuvrM0uOgXWCzhEaRwbczAdnFiRv+L TxnQHRyBraiRrKEWlVsOExbS4xHDhHaBw2fKCrPbVa6NbxQ4I8qJiiDUW0KIDAsx6ueuCxANKi2hO 6HiPrLmwfa6w+HvuGiIfDVs4QHtqTAlrf6uQ3LGi/BzZjtNg2MVgQy3sRhFmkGJWLwe+D4NNf7g67 n+OfP4k0AkUrcz9HVxcrdoq4vlAlGIKqRhLbiY50LZCOhOhCCpOwR1UKz2A69uBfZ3l6CKPJxIsME TpGYb54G7JMpcJF7kFPQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1puXF7-007ff6-2A; Thu, 04 May 2023 11:35:25 +0000 Received: from madras.collabora.co.uk ([46.235.227.172]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1puXF4-007fcz-1O; Thu, 04 May 2023 11:35:23 +0000 Received: from IcarusMOD.eternityproject.eu (unknown [IPv6:2001:b07:2ed:14ed:c5f8:7372:f042:90a2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by madras.collabora.co.uk (Postfix) with ESMTPSA id 981BD66032D1; Thu, 4 May 2023 12:35:16 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1683200117; bh=oYDe/VXfJGa+IBEXNZZL8Wjnx24xldbrD++GRNp7wf8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SSY9a5QIjnOdxPA/nZt/sT2nUHh81bauNVLFJmH9cSX+HGZD4TACaot8H0bR8D23L ySp40BxxMq+oXusx1z8QEq56Gcy6IwgsSYbl8bEpH/6dpRebt9lznmGBTTtk5NwX7t Q97j8u24JQfFH/K1/zSpXU+s4RP/+JZxhw8kwvCbM7UbgSaF4yGncb6JdbFCGJeyT4 8e5GVRzCvv0KNWKK1hyjwS5jZjNxCCYUbkYdBMXSbjTqoFjyrBF0JuwESQRoU6weIn 8ioIlSAUata3gYwRmFZLJMd1FKYksDMex1zYtBGsgfRQruvoPRAy3A1jJ15lIPheG4 qcjCPyNSKplQQ== From: AngeloGioacchino Del Regno To: ryder.lee@mediatek.com Cc: jianjun.wang@mediatek.com, lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, p.zabel@pengutronix.de, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] PCI: mediatek-gen3: Stop acquiring spinlocks in {suspend,resume}_noirq Date: Thu, 4 May 2023 13:35:08 +0200 Message-Id: <20230504113509.184633-2-angelogioacchino.delregno@collabora.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230504113509.184633-1-angelogioacchino.delregno@collabora.com> References: <20230504113509.184633-1-angelogioacchino.delregno@collabora.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230504_043522_603303_5E583190 X-CRM114-Status: UNSURE ( 9.77 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In mtk_pcie_suspend_noirq() and mtk_pcie_resume_noirq() we are, respectively, disabling and enabling generation of interrupts and then saving and restoring the enabled interrupts register: since we're using noirq PM callbacks, that can be safely done without holding any spin lock. That was noticed because of, and solves, the following issue: <4>[ 74.185982] ======================================================== <4>[ 74.192629] WARNING: possible irq lock inversion dependency detected <4>[ 74.199276] 6.3.0-next-20230428+ #51 Tainted: G W <4>[ 74.205664] -------------------------------------------------------- <4>[ 74.212309] systemd-sleep/809 just changed the state of lock: <4>[ 74.218347] ffff65a5c34c65a0 (&pcie->irq_lock){+...}-{2:2}, at: mtk_pcie_resume+0x50/0xa8 <4>[ 74.226870] but this lock was taken by another, HARDIRQ-safe lock in the past: <4>[ 74.234389] (&irq_desc_lock_class){-.-.}-{2:2} <4>[ 74.234409] <4>[ 74.234409] <4>[ 74.234409] and interrupts could create inverse lock ordering between them. <4>[ 74.234409] <4>[ 74.251704] <4>[ 74.251704] other info that might help us debug this: <4>[ 74.258785] Possible interrupt unsafe locking scenario: <4>[ 74.258785] <4>[ 74.266126] CPU0 CPU1 <4>[ 74.270942] ---- ---- <4>[ 74.275758] lock(&pcie->irq_lock); <4>[ 74.279627] local_irq_disable(); <4>[ 74.285836] lock(&irq_desc_lock_class); <4>[ 74.292667] lock(&pcie->irq_lock); <4>[ 74.299061] <4>[ 74.301960] lock(&irq_desc_lock_class); <4>[ 74.306438] <4>[ 74.306438] *** DEADLOCK *** Fixes: d537dc125f07 ("PCI: mediatek-gen3: Add system PM support") Signed-off-by: AngeloGioacchino Del Regno --- drivers/pci/controller/pcie-mediatek-gen3.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index b8612ce5f4d0..52f52ca5db71 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -963,8 +963,6 @@ static void mtk_pcie_irq_save(struct mtk_gen3_pcie *pcie) { int i; - raw_spin_lock(&pcie->irq_lock); - pcie->saved_irq_state = readl_relaxed(pcie->base + PCIE_INT_ENABLE_REG); for (i = 0; i < PCIE_MSI_SET_NUM; i++) { @@ -973,16 +971,12 @@ static void mtk_pcie_irq_save(struct mtk_gen3_pcie *pcie) msi_set->saved_irq_state = readl_relaxed(msi_set->base + PCIE_MSI_SET_ENABLE_OFFSET); } - - raw_spin_unlock(&pcie->irq_lock); } static void mtk_pcie_irq_restore(struct mtk_gen3_pcie *pcie) { int i; - raw_spin_lock(&pcie->irq_lock); - writel_relaxed(pcie->saved_irq_state, pcie->base + PCIE_INT_ENABLE_REG); for (i = 0; i < PCIE_MSI_SET_NUM; i++) { @@ -991,8 +985,6 @@ static void mtk_pcie_irq_restore(struct mtk_gen3_pcie *pcie) writel_relaxed(msi_set->saved_irq_state, msi_set->base + PCIE_MSI_SET_ENABLE_OFFSET); } - - raw_spin_unlock(&pcie->irq_lock); } static int mtk_pcie_turn_off_link(struct mtk_gen3_pcie *pcie)