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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 996DAC433E0 for ; Tue, 30 Jun 2020 21:18:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D2A02083B for ; Tue, 30 Jun 2020 21:18:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730031AbgF3VSp (ORCPT ); Tue, 30 Jun 2020 17:18:45 -0400 Received: from gate.crashing.org ([63.228.1.57]:48640 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725805AbgF3VSo (ORCPT ); Tue, 30 Jun 2020 17:18:44 -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 05ULIIPG003747; Tue, 30 Jun 2020 16:18:18 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 05ULIHW0003746; Tue, 30 Jun 2020 16:18:17 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 30 Jun 2020 16:18:17 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , npiggin@gmail.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] powerpc/uaccess: Use flexible addressing with __put_user()/__get_user() Message-ID: <20200630211817.GZ3598@gate.crashing.org> References: <7b916759-1683-b4df-0d4b-b04b3fcd9a02@csgroup.eu> <878sg6862r.fsf@mpe.ellerman.id.au> <875zb98i5a.fsf@mpe.ellerman.id.au> <311c3471-cad7-72d5-a5e6-04cf892c5e41@csgroup.eu> <20200630163324.GW3598@gate.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi again, Thanks for your work so far! On Tue, Jun 30, 2020 at 06:53:39PM +0000, Christophe Leroy wrote: > On 06/30/2020 04:33 PM, Segher Boessenkool wrote: > >>>+ make -s CC=powerpc64-linux-gnu-gcc -j 160 > >>>In file included from /linux/include/linux/uaccess.h:11:0, > >>> from /linux/include/linux/sched/task.h:11, > >>> from /linux/include/linux/sched/signal.h:9, > >>> from /linux/include/linux/rcuwait.h:6, > >>> from /linux/include/linux/percpu-rwsem.h:7, > >>> from /linux/include/linux/fs.h:33, > >>> from /linux/include/linux/huge_mm.h:8, > >>> from /linux/include/linux/mm.h:675, > >>> from /linux/arch/powerpc/kernel/signal_32.c:17: > >>>/linux/arch/powerpc/kernel/signal_32.c: In function > >>>'save_user_regs.isra.14.constprop': > >>>/linux/arch/powerpc/include/asm/uaccess.h:161:2: error: 'asm' operand has > >>>impossible constraints > >>> __asm__ __volatile__( \ > >>> ^ > >>>/linux/arch/powerpc/include/asm/uaccess.h:197:12: note: in expansion of > >>>macro '__put_user_asm' > >>> case 4: __put_user_asm(x, ptr, retval, "stw"); break; \ > >>> ^ > >>>/linux/arch/powerpc/include/asm/uaccess.h:206:2: note: in expansion of > >>>macro '__put_user_size_allowed' > >>> __put_user_size_allowed(x, ptr, size, retval); \ > >>> ^ > >>>/linux/arch/powerpc/include/asm/uaccess.h:220:2: note: in expansion of > >>>macro '__put_user_size' > >>> __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \ > >>> ^ > >>>/linux/arch/powerpc/include/asm/uaccess.h:96:2: note: in expansion of > >>>macro '__put_user_nocheck' > >>> __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) > >>> ^ > >>>/linux/arch/powerpc/kernel/signal_32.c:120:7: note: in expansion of macro > >>>'__put_user' > >>> if (__put_user((unsigned int)gregs[i], &frame->mc_gregs[i])) > >>> ^ > > > >Can we see what that was after the macro jungle? Like, the actual > >preprocessed code? > > Sorry for previous misunderstanding > > Here is the code: > > #define __put_user_asm(x, addr, err, op) \ > __asm__ __volatile__( \ > "1: " op "%U2%X2 %1,%2 # put_user\n" \ > "2:\n" \ > ".section .fixup,\"ax\"\n" \ > "3: li %0,%3\n" \ > " b 2b\n" \ > ".previous\n" \ > EX_TABLE(1b, 3b) \ > : "=r" (err) \ > : "r" (x), "m<>" (*addr), "i" (-EFAULT), "0" (err)) Yeah I don't see it. I'll have to look at compiler debug dumps, but I don't have any working 4.9 around, and I cannot reproduce this with either older or newer compilers. It is complainig that constrain_operands just does not work *at all* on this "m<>" constraint apparently, which doesn't make much sense. I'll try later when I have more time, sorry :-/ Segher