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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 62E8BC52D59 for ; Thu, 27 Feb 2020 13:59:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F26B24656 for ; Thu, 27 Feb 2020 13:59:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811942; bh=WejT3Jlm73icaZYufA+h2E/dA+9hbApxdmiA8FvbewE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PTet8q1y2jdCAlygXFXp68uUx/8HQ1zEVbAP2W8UnDk9KqmpDmEumVuU19ebeksfG PrquBMJvC1sTh7Pwn2ESYVv4/+Wf2RrGRU8wByo3XrsE3dT5Kk0E85CX6BXqJLhQ8O g8TS2qtrsfS7r56x1+Gbrr/bO0S9OrsW76s8vPC0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732554AbgB0N7B (ORCPT ); Thu, 27 Feb 2020 08:59:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:60206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732343AbgB0N64 (ORCPT ); Thu, 27 Feb 2020 08:58:56 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 4CC9D2084E; Thu, 27 Feb 2020 13:58:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811935; bh=WejT3Jlm73icaZYufA+h2E/dA+9hbApxdmiA8FvbewE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GwoDjw//6mEvOky6uY+ef5Z9sEGjXr6NvOpLjDfQfeWBNIy9kJSDnbbYrVN6DFUU0 w74qG2gX4BjZFdV2G9aIbUsVonWqEBJ8mSBSwtkjfYXrUuM6woaQUDaIb7kGKzSA2j hKDLmrKwGUs0v4wycJXbb60TBndOSwyulS8rf5JE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jean-Philippe Brucker , Will Deacon , Sasha Levin Subject: [PATCH 4.14 121/237] iommu/arm-smmu-v3: Use WRITE_ONCE() when changing validity of an STE Date: Thu, 27 Feb 2020 14:35:35 +0100 Message-Id: <20200227132305.709086840@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132255.285644406@linuxfoundation.org> References: <20200227132255.285644406@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: Will Deacon [ Upstream commit d71e01716b3606a6648df7e5646ae12c75babde4 ] If, for some bizarre reason, the compiler decided to split up the write of STE DWORD 0, we could end up making a partial structure valid. Although this probably won't happen, follow the example of the context-descriptor code and use WRITE_ONCE() to ensure atomicity of the write. Reported-by: Jean-Philippe Brucker Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/iommu/arm-smmu-v3.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 09eb258a9a7de..29feafa8007fb 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -1145,7 +1145,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, } arm_smmu_sync_ste_for_sid(smmu, sid); - dst[0] = cpu_to_le64(val); + /* See comment in arm_smmu_write_ctx_desc() */ + WRITE_ONCE(dst[0], cpu_to_le64(val)); arm_smmu_sync_ste_for_sid(smmu, sid); /* It's likely that we'll want to use the new STE soon */ -- 2.20.1