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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 85675C4363A for ; Sat, 24 Oct 2020 10:28:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4655722210 for ; Sat, 24 Oct 2020 10:28:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760937AbgJXK17 (ORCPT ); Sat, 24 Oct 2020 06:27:59 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:51663 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760929AbgJXK17 (ORCPT ); Sat, 24 Oct 2020 06:27:59 -0400 Received: by ozlabs.org (Postfix, from userid 1034) id 4CJHNs1yYGz9sV1; Sat, 24 Oct 2020 21:27:57 +1100 (AEDT) From: Michael Ellerman To: Michael Ellerman , Christophe Leroy , Paul Mackerras , Benjamin Herrenschmidt , mathieu.desnoyers@efficios.com Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org In-Reply-To: <212d3bc4a52ca71523759517bb9c61f7e477c46a.1603179582.git.christophe.leroy@csgroup.eu> References: <212d3bc4a52ca71523759517bb9c61f7e477c46a.1603179582.git.christophe.leroy@csgroup.eu> Subject: Re: [PATCH v2 1/3] powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9 Message-Id: <160353524065.3419015.15517113357931210947.b4-ty@ellerman.id.au> Date: Sat, 24 Oct 2020 21:27:57 +1100 (AEDT) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 20 Oct 2020 07:40:07 +0000 (UTC), Christophe Leroy wrote: > GCC 4.9 sometimes fails to build with "m<>" constraint in > inline assembly. > > CC lib/iov_iter.o > In file included from ./arch/powerpc/include/asm/cmpxchg.h:6:0, > from ./arch/powerpc/include/asm/atomic.h:11, > from ./include/linux/atomic.h:7, > from ./include/linux/crypto.h:15, > from ./include/crypto/hash.h:11, > from lib/iov_iter.c:2: > lib/iov_iter.c: In function 'iovec_from_user.part.30': > ./arch/powerpc/include/asm/uaccess.h:287:2: error: 'asm' operand has impossible constraints > __asm__ __volatile__( \ > ^ > ./include/linux/compiler.h:78:42: note: in definition of macro 'unlikely' > # define unlikely(x) __builtin_expect(!!(x), 0) > ^ > ./arch/powerpc/include/asm/uaccess.h:583:34: note: in expansion of macro 'unsafe_op_wrap' > #define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e) > ^ > ./arch/powerpc/include/asm/uaccess.h:329:10: note: in expansion of macro '__get_user_asm' > case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break; \ > ^ > ./arch/powerpc/include/asm/uaccess.h:363:3: note: in expansion of macro '__get_user_size_allowed' > __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \ > ^ > ./arch/powerpc/include/asm/uaccess.h:100:2: note: in expansion of macro '__get_user_nocheck' > __get_user_nocheck((x), (ptr), sizeof(*(ptr)), false) > ^ > ./arch/powerpc/include/asm/uaccess.h:583:49: note: in expansion of macro '__get_user_allowed' > #define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e) > ^ > lib/iov_iter.c:1663:3: note: in expansion of macro 'unsafe_get_user' > unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); > ^ > make[1]: *** [scripts/Makefile.build:283: lib/iov_iter.o] Error 1 > > [...] Patch 1 applied to powerpc/fixes. [1/3] powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9 https://git.kernel.org/powerpc/c/592bbe9c505d9a0ef69260f8c8263df47da2698e cheers