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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, 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 A4E5DC3279B for ; Sun, 8 Jul 2018 17:58:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54980208CA for ; Sun, 8 Jul 2018 17:58:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hqOtFrxk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54980208CA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932437AbeGHR6o (ORCPT ); Sun, 8 Jul 2018 13:58:44 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:39580 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754239AbeGHR6n (ORCPT ); Sun, 8 Jul 2018 13:58:43 -0400 Received: by mail-lj1-f193.google.com with SMTP id t7-v6so12425901ljj.6; Sun, 08 Jul 2018 10:58:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=C3ewxTalH0Xjzs4mLGQ5RRfJQ7855pQzE7NHTdIYvgk=; b=hqOtFrxk3hJPa/8DPu0GYEMFeF+hCGr7dQi7A1Rzz7gh6pDYNNFlTQBK6ACCNyS6Qa qCTpU2qLcoXZ52s/RVkXLf1k7qd90nR95I/IssN5b+0KmAcMaQnOXQ1ZNafuJJ3Yei94 DmISwkBjKDqc1aOLyEEmO98eue2ZuJ9/vrgYY/A22/uEjgFEllWa67VnL00jAn40q7Bo 06Grc0QDDmsS1EcjMiItc2xpVTPpoD2/y4cX+LzyMWlfKct+s28ED0Lo2//vzgmuL/fi mLU6tRLueZYWy8pKzFEfGFqLxElOuqPf3iFmMTl+IsXt3e9KRbA106dH+E5qqQ9PWbYN LdyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=C3ewxTalH0Xjzs4mLGQ5RRfJQ7855pQzE7NHTdIYvgk=; b=hiJ5EZmDuT03hCnxKiwqECca+0XP/6onRDRUkLEZrP7FDVZ9gA0EhgMTeVrdsG4Xto SoY2PdiAFyJTL08Os2m3Zb6x4dCc9QdEgByY2PBFuS77vuQmWy89Yd5fPUmEi8Dx3/XA karV0gVQ+T4N3gK5uVtqBZsXs2GEfIv6QenHYQO4p34MI//WDCDR7Y6oaaOaRZrsOrHu dNcj3+UUdmwGlJOR+GZQjbD2GQNG0YyZbGFoqNPCdUldSDOkEhnzjOx1oSlOeB6m31R9 XQXFXF/Y1xPsm0oKdr1Mbg7nlLYB4iIdOb4lIuZlyc3LaG8Yed5Tg/ZS6ojFGo+HYVUk vNLQ== X-Gm-Message-State: APt69E2qNFHPwaPbDrF2Xv1vvbQOsgH5RCtm45Qa66x6w1ltD3SMAH1M 94kIoNFf5lRFXkk21I08380zWsJgp4Q= X-Google-Smtp-Source: AAOMgpdGq8qqEhBua4PD3sG87A2Ec1eI+71gXN61dvj/lpMCb7HlUp0UF0Yxuap7reDngL/QU4j/AA== X-Received: by 2002:a2e:9d0e:: with SMTP id t14-v6mr6668189lji.112.1531072720998; Sun, 08 Jul 2018 10:58:40 -0700 (PDT) Received: from abrodkin-7480l.local ([91.237.150.126]) by smtp.gmail.com with ESMTPSA id a26-v6sm2033171ljd.12.2018.07.08.10.58.39 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 08 Jul 2018 10:58:39 -0700 (PDT) From: Alexey Brodkin X-Google-Original-From: Alexey Brodkin To: linux-kernel@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org, linux-arch@vger.kernel.org, Alexey Brodkin , Thomas Gleixner , stable@vger.kernel.org Subject: [PATCH v2] devres: Really align data field to unsigned long long Date: Sun, 8 Jul 2018 20:56:21 +0300 Message-Id: <20180708175621.6951-1-abrodkin@synopsys.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Depending on ABI "long long" type of a particular 32-bit CPU might be aligned by either word (32-bits) or double word (64-bits). Make sure "data" is really 64-bit aligned for any 32-bit CPU. At least for 32-bit ARC cores ABI requires "long long" types to be aligned by normal 32-bit word. This makes "data" field aligned to 12 bytes. Which is still OK as long as we use 32-bit data only. But once we want to use native atomic64_t type (i.e. when we use special instructions LLOCKD/SCONDD for accessing 64-bit data) we easily hit misaligned access exception. That's because even on CPUs capable of non-aligned data access LL/SC instructions require strict alignment. Signed-off-by: Alexey Brodkin Cc: Thomas Gleixner Cc: stable@vger.kernel.org --- Changes v1 -> v2: * Reworded commit message * Inserted comment right in source [Thomas] drivers/base/devres.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/base/devres.c b/drivers/base/devres.c index f98a097e73f2..466fa59c866a 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -24,8 +24,12 @@ struct devres_node { struct devres { struct devres_node node; - /* -- 3 pointers */ - unsigned long long data[]; /* guarantee ull alignment */ + /* + * Depending on ABI "long long" type of a particular 32-bit CPU + * might be aligned by either word (32-bits) or double word (64-bits). + * Make sure "data" is really 64-bit aligned for any 32-bit CPU. + */ + unsigned long long data[] __aligned(sizeof(unsigned long long)); }; struct devres_group { -- 2.17.1