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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 8D1F1C3B1A1 for ; Fri, 14 Feb 2020 16:09:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5BCE624680 for ; Fri, 14 Feb 2020 16:09:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696543; bh=LF0kKZuLa+zTPv5urFxUqbzEBwsa/nVldpj14g4r4Ks=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xjgjizGk6BliFAAEiT0L8paMJhVTdVZdmofsq0YRusMbcPYev+tMXN2L3FVaJesPW 8Wk/or46Gy1tFgzmCdGRC11Em6nz/AXPubxhe3lopEAeqQzj5jTZdez8Ezeun9TdGn YVIb7vX6efn0AdIfhxHNZlxYw2BmO3VSbbc538S0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391168AbgBNQJC (ORCPT ); Fri, 14 Feb 2020 11:09:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:60838 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391033AbgBNQIm (ORCPT ); Fri, 14 Feb 2020 11:08:42 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8C32224680; Fri, 14 Feb 2020 16:08:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696522; bh=LF0kKZuLa+zTPv5urFxUqbzEBwsa/nVldpj14g4r4Ks=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kc+vEUKlR7pfo6oW9dH5TJxOxEASSG7+2oB4alB9A+/0ajmIvHW9ymwVRjh7LBmUQ TmpRHRuqhEX6fgGvYecFZsGeWIjsrDoJNjSqf4rpZG1/2uT/5OammhQfe96NT8lWj3 j10o5WBwN1zvxNp/xikBjJof09aaMpLaI6bknRbY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Will Deacon , Jean-Philippe Brucker , Sasha Levin , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org Subject: [PATCH AUTOSEL 5.4 322/459] iommu/arm-smmu-v3: Use WRITE_ONCE() when changing validity of an STE Date: Fri, 14 Feb 2020 10:59:32 -0500 Message-Id: <20200214160149.11681-322-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 ee8d48d863e16..ef6af714a7e64 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -1643,7 +1643,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, STRTAB_STE_1_EATS_TRANS)); 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