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 3F2A4C433DF for ; Mon, 19 Oct 2020 20:14:51 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D80C4223BE for ; Mon, 19 Oct 2020 20:14:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D80C4223BE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4CFSfH0DSvzDqYn for ; Tue, 20 Oct 2020 07:14:47 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 4CFScN6JyCzDqKg for ; Tue, 20 Oct 2020 07:13:08 +1100 (AEDT) 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 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 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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