From patchwork Wed Feb 10 15:08:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 61675 Delivered-To: patch@linaro.org Received: by 10.112.43.199 with SMTP id y7csp2704037lbl; Wed, 10 Feb 2016 07:18:29 -0800 (PST) X-Received: by 10.67.7.200 with SMTP id de8mr59311750pad.28.1455117496876; Wed, 10 Feb 2016 07:18:16 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id w83si5696097pfa.51.2016.02.10.07.18.16; Wed, 10 Feb 2016 07:18:16 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752817AbcBJPMy (ORCPT + 3 others); Wed, 10 Feb 2016 10:12:54 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:46062 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752791AbcBJPMt (ORCPT ); Wed, 10 Feb 2016 10:12:49 -0500 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u1AFChbs023071 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 10 Feb 2016 15:12:43 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.13.8/8.13.8) with ESMTP id u1AFCgLI015884 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Wed, 10 Feb 2016 15:12:43 GMT Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u1AFCgVX004190; Wed, 10 Feb 2016 15:12:42 GMT Received: from lappy.us.oracle.com (/10.154.137.179) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 10 Feb 2016 07:12:42 -0800 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Will Deacon , Sasha Levin Subject: [added to the 4.1 stable tree] arm64: mdscr_el1: avoid exposing DCC to userspace Date: Wed, 10 Feb 2016 10:08:48 -0500 Message-Id: <1455117136-28870-24-git-send-email-sasha.levin@oracle.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1455117136-28870-1-git-send-email-sasha.levin@oracle.com> References: <1455117136-28870-1-git-send-email-sasha.levin@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Will Deacon This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html =============== [ Upstream commit d8d23fa0f27f3b2942a7bbc7378c7735324ed519 ] We don't want to expose the DCC to userspace, particularly as there is a kernel console driver for it. This patch resets mdscr_el1 to disable userspace access to the DCC registers on the cold boot path. Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/mm/proc.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index cdd754e..d2c2e3b 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -202,7 +202,8 @@ ENTRY(__cpu_setup) mov x0, #3 << 20 msr cpacr_el1, x0 // Enable FP/ASIMD - msr mdscr_el1, xzr // Reset mdscr_el1 + mov x0, #1 << 12 // Reset mdscr_el1 and disable + msr mdscr_el1, x0 // access to the DCC from EL0 /* * Memory region attributes for LPAE: *