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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 4A9CBC282DB for ; Sun, 3 Feb 2019 13:57:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24E0C21906 for ; Sun, 3 Feb 2019 13:57:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728368AbfBCNuA (ORCPT ); Sun, 3 Feb 2019 08:50:00 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52756 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727773AbfBCNtm (ORCPT ); Sun, 3 Feb 2019 08:49:42 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqI9T-0003tr-Dm; Sun, 03 Feb 2019 13:49:39 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9T-0006o0-QY; Sun, 03 Feb 2019 14:49:39 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Bernd Edlinger" , "Arnd Bergmann" , "Greg Kroah-Hartman" , "Johannes Pointner" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 013/305] ARM: fix put_user() for gcc-8 In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann Building kernels before linux-4.7 with gcc-8 results in many build failures when gcc triggers a check that was meant to catch broken compilers: /tmp/ccCGMQmS.s:648: Error: .err encountered According to the discussion in the gcc bugzilla, a local "register asm()" variable is still supposed to be the correct way to force an inline assembly to use a particular register, but marking it 'const' lets the compiler do optimizations that break that, i.e the compiler is free to treat the variable as either 'const' or 'register' in that case. Upstream commit 9f73bd8bb445 ("ARM: uaccess: remove put_user() code duplication") fixed this problem in linux-4.8 as part of a larger change, but seems a little too big to be backported to 4.4. Let's take the simplest fix and change only the one broken line in the same way as newer kernels. Suggested-by: Bernd Edlinger Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85745 Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86673 Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman Cc: Johannes Pointner Signed-off-by: Ben Hutchings --- arch/arm/include/asm/uaccess.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -172,7 +172,7 @@ extern int __put_user_8(void *, unsigned ({ \ unsigned long __limit = current_thread_info()->addr_limit - 1; \ const typeof(*(p)) __user *__tmp_p = (p); \ - register const typeof(*(p)) __r2 asm("r2") = (x); \ + register typeof(*(p)) __r2 asm("r2") = (x); \ register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \