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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 B5142C6778F for ; Mon, 9 Jul 2018 04:45:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 028F7208DB for ; Mon, 9 Jul 2018 04:45:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="iqfyenw2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 028F7208DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=synopsys.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 S932231AbeGIEpA (ORCPT ); Mon, 9 Jul 2018 00:45:00 -0400 Received: from smtprelay4.synopsys.com ([198.182.47.9]:37974 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbeGIEo6 (ORCPT ); Mon, 9 Jul 2018 00:44:58 -0400 Received: from mailhost.synopsys.com (mailhost3.synopsys.com [10.12.238.238]) by smtprelay.synopsys.com (Postfix) with ESMTP id 5AB5C24E229D; Sun, 8 Jul 2018 21:44:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1531111498; bh=yaiz/OMXY4OwQyCA8PAtPxBmZBM6Ex7xnI+AEj7QvtY=; h=From:To:Cc:Subject:Date:From; b=iqfyenw2syKVZszXl3odcpRkjkNAtl78WF3wvvQqSvjQE4UM7HlNaDuvXQAUnKYUS ZFFTrtMpMs8GV78gGLupiiun8CYPco/QrtPyAs7Zn2xLmcP4RtS4zRNxUozkuReIIJ CHs9KIN1gVts2gk4rZrfxBt2Q8gtRKHNOiCrVX7nknJvAoCozk3J0W68GyTR8DipCe JMittQNX0LA+ZfQPibFnNYN+4gJfgN9XnCVnnfWY2BW4lAlu04WrXhtFS0twD9prL6 Mg7D1EcdlTcnECliG7PMNjKfNnP/6Ti7FinzbtGf76O+/da3EZD2M8llPuO4PiU+A4 RM09ZxD0HPyHg== Received: from abrodkin-7480l.internal.synopsys.com (unknown [10.121.8.87]) by mailhost.synopsys.com (Postfix) with ESMTP id 939EC3A2B; Sun, 8 Jul 2018 21:44:54 -0700 (PDT) From: Alexey Brodkin To: linux-kernel@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org, linux-arch@vger.kernel.org, Greg KH , Alexey Brodkin , Greg Kroah-Hartman , Thomas Gleixner , stable@vger.kernel.org Subject: [RESEND PATCH v2] devres: Really align data field to unsigned long long Date: Mon, 9 Jul 2018 07:44:44 +0300 Message-Id: <20180709044444.6397-1-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: Greg Kroah-Hartman 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