From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out.m-online.net (mail-out.m-online.net [IPv6:2001:a60:0:28:0:1:25:1]) by sourceware.org (Postfix) with ESMTPS id F12A43858004 for ; Mon, 22 Mar 2021 14:42:48 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org F12A43858004 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=whitebox@nefkom.net Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4F3y076wkZz1s2Bd; Mon, 22 Mar 2021 15:42:47 +0100 (CET) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4F3y076YwZz1qvBm; Mon, 22 Mar 2021 15:42:47 +0100 (CET) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id AwboGaW35gAN; Mon, 22 Mar 2021 15:42:47 +0100 (CET) X-Auth-Info: BtaqJFoTS9gai6zd5lufTtMu1Gy/ny5aYDztFmnw4ku+CI5meYJHjZzl1MWF19Lj Received: from igel.home (ppp-46-244-186-141.dynamic.mnet-online.de [46.244.186.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Mon, 22 Mar 2021 15:42:47 +0100 (CET) Received: by igel.home (Postfix, from userid 1000) id 8BF8F2C3227; Mon, 22 Mar 2021 15:42:46 +0100 (CET) From: Andreas Schwab To: Matheus Castanho via Libc-alpha Cc: Matheus Castanho , tuliom@linux.ibm.com, npiggin@gmail.com Subject: Re: [PATCH] powerpc: Add missing registers to clobbers list for syscalls [BZ #27623] References: <20210322142035.183915-1-msc@linux.ibm.com> X-Yow: What PROGRAM are they watching? Date: Mon, 22 Mar 2021 15:42:46 +0100 In-Reply-To: <20210322142035.183915-1-msc@linux.ibm.com> (Matheus Castanho via Libc-alpha's message of "Mon, 22 Mar 2021 11:20:35 -0300") Message-ID: <87k0pzmeqh.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Mar 2021 14:42:50 -0000 On Mär 22 2021, Matheus Castanho via Libc-alpha wrote: > Some registers that can be clobbered by the kernel during a syscall are not > listed on the clobbers list in sysdeps/unix/sysv/linux/powerpc/sysdep.h. > > For syscalls using sc: > - XER is zeroed by the kernel on exit > > For syscalls using scv: > - XER is zeroed by the kernel on exit > - Different from the sc case, most CR fields can be clobbered (according to > the ELF ABI and the Linux kernel's syscall ABI for powerpc > (linux/Documentation/powerpc/syscall64-abi.rst) > > These are likely not causing issues today, but they should be added to the > clobbers list just in case things change on the kernel side in the future. What about INTERNAL_VSYSCALL_CALL_TYPE? Doesn't that clobber XER[CA] and CR1/5/6/7 like ordinary function calls? Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."