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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 06E2AC433E7 for ; Mon, 19 Oct 2020 20:16:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92ADF223EA for ; Mon, 19 Oct 2020 20:16:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731458AbgJSUQ0 (ORCPT ); Mon, 19 Oct 2020 16:16:26 -0400 Received: from gate.crashing.org ([63.228.1.57]:44972 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726118AbgJSUQZ (ORCPT ); Mon, 19 Oct 2020 16:16:25 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 09JKAlXU020418; Mon, 19 Oct 2020 15:10:47 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 09JKAkCX020411; Mon, 19 Oct 2020 15:10:46 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 19 Oct 2020 15:10:45 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9 Message-ID: <20201019201045.GS2672@gate.crashing.org> References: <5ffcb064f695d5285bf1faab91bffa3f9245fc26.1603109522.git.christophe.leroy@csgroup.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5ffcb064f695d5285bf1faab91bffa3f9245fc26.1603109522.git.christophe.leroy@csgroup.eu> User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 19, 2020 at 12:12:46PM +0000, Christophe Leroy wrote: > GCC 4.9 sometimes fails to build with "m<>" constraint in > inline assembly. > --- a/arch/powerpc/include/asm/uaccess.h > +++ b/arch/powerpc/include/asm/uaccess.h > @@ -223,7 +223,7 @@ do { \ > "1: " op "%U1%X1 %0,%1 # put_user\n" \ > EX_TABLE(1b, %l2) \ > : \ > - : "r" (x), "m<>" (*addr) \ > + : "r" (x), "m"UPD_CONSTR (*addr) \ > : \ > : label) > > @@ -294,7 +294,7 @@ extern long __get_user_bad(void); > ".previous\n" \ > EX_TABLE(1b, 3b) \ > : "=r" (err), "=r" (x) \ > - : "m<>" (*addr), "i" (-EFAULT), "0" (err)) > + : "m"UPD_CONSTR (*addr), "i" (-EFAULT), "0" (err)) Wow, ugly! But these are the only two places that use this, so Acked-by: Segher Boessenkool I just hope that we get rid of 4.9 before we would use this a lot more ;-) Segher