From patchwork Thu May 23 08:54:02 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gregory CLEMENT X-Patchwork-Id: 2606291 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork2.kernel.org (Postfix) with ESMTP id 74F03DFB78 for ; Thu, 23 May 2013 11:11:32 +0000 (UTC) Received: from merlin.infradead.org ([205.233.59.134]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UfRK6-0003BX-14; Thu, 23 May 2013 08:56:36 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UfRIg-0005U1-Re; Thu, 23 May 2013 08:55:06 +0000 Received: from mail.free-electrons.com ([94.23.35.102]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UfRIW-0005Sf-H8 for linux-arm-kernel@lists.infradead.org; Thu, 23 May 2013 08:54:57 +0000 Received: by mail.free-electrons.com (Postfix, from userid 106) id E6FB482E; Thu, 23 May 2013 10:54:35 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on mail.free-electrons.com X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,SHORTCIRCUIT shortcircuit=ham autolearn=disabled version=3.3.2 Received: from localhost (tra42-5-83-152-246-54.fbx.proxad.net [83.152.246.54]) by mail.free-electrons.com (Postfix) with ESMTPSA id 2C77D744; Thu, 23 May 2013 10:54:35 +0200 (CEST) From: Gregory CLEMENT To: Jason Cooper , Andrew Lunn , Gregory CLEMENT Subject: [PATCH] ARM: mvebu: Fix bug in coherency fabric low level init function Date: Thu, 23 May 2013 10:54:02 +0200 Message-Id: <1369299242-16506-2-git-send-email-gregory.clement@free-electrons.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1369299242-16506-1-git-send-email-gregory.clement@free-electrons.com> References: <1369299242-16506-1-git-send-email-gregory.clement@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130523_045456_726353_955A9768 X-CRM114-Status: GOOD ( 10.48 ) X-Spam-Score: -3.0 (---) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-3.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record -1.1 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Thomas Petazzoni , Lior Amsalem , Yehuda Yitschak , Ike Pan , Tawfik Bayouk , Nicolas Pitre , Dan Frazier , Chris Van Hoof , David Marlin , Eran Ben-Avi , Nadav Haklai , Maen Suleiman , Shadi Ammouri , Ezequiel Garcia , Jon Masters , Leif Lindholm , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Nadav Haklai When adding CPU to the SMP group and enabling the coherency on this CPU we must protect the register access. The previous implementation claims to be atomic but doesn't provide any protection against parallel access to the coherency fabric control and configuration registers. This patch fixes this by using the ldrex and strex mechanism. This method should be used in all accesses to those registers. [gregory.clement@free-electrons.com: fixed the commit's topic] Signed-off-by: Nadav Haklai Signed-off-by: Gregory CLEMENT --- arch/arm/mach-mvebu/coherency_ll.S | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S index 53e8391..5476669 100644 --- a/arch/arm/mach-mvebu/coherency_ll.S +++ b/arch/arm/mach-mvebu/coherency_ll.S @@ -32,15 +32,21 @@ ENTRY(ll_set_cpu_coherent) /* Add CPU to SMP group - Atomic */ add r3, r0, #ARMADA_XP_CFB_CTL_REG_OFFSET - ldr r2, [r3] +1: + ldrex r2, [r3] orr r2, r2, r1 - str r2, [r3] + strex r0, r2, [r3] + cmp r0, #0 + bne 1b /* Enable coherency on CPU - Atomic */ - add r3, r0, #ARMADA_XP_CFB_CFG_REG_OFFSET - ldr r2, [r3] + add r3, r3, #ARMADA_XP_CFB_CFG_REG_OFFSET +1: + ldrex r2, [r3] orr r2, r2, r1 - str r2, [r3] + strex r0, r2, [r3] + cmp r0, #0 + bne 1b dsb