From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 50161 invoked by alias); 2 Aug 2018 09:17:38 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 49647 invoked by uid 89); 2 Aug 2018 09:17:37 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mx1.redhat.com Subject: Re: [PATCH 00/12] S390: Implement __fentry__ To: Ilya Leoshkevich , libc-alpha@sourceware.org Cc: stli@linux.ibm.com References: <20180802075735.3457-1-iii@linux.ibm.com> From: Florian Weimer Message-ID: Date: Thu, 02 Aug 2018 09:17:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180802075735.3457-1-iii@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2018-08/txt/msg00039.txt.bz2 On 08/02/2018 09:57 AM, Ilya Leoshkevich wrote: > This patch series adds the runtime support in glibc for the -mfentry > gcc feature introduced in [1] and [2]. > > Patches 1-9 deal with avoiding clobbering %r0 when calling lazily bound > functions, so that the new __fentry__ symbol could be called with return > address in that register. Should GCC arrange for suitable ABI markup if -mfentry is used? I'm worried that unexpected clobbers of r0 could be quite difficult to figure out otherwise. Thanks, Florian