From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30089 invoked by alias); 26 Mar 2018 15:42:37 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 28733 invoked by uid 89); 26 Mar 2018 15:42:36 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.0 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy= X-HELO: mx1.redhat.com Received: from mx3-rdu2.redhat.com (HELO mx1.redhat.com) (66.187.233.73) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 26 Mar 2018 15:42:35 +0000 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 457854068026; Mon, 26 Mar 2018 15:42:34 +0000 (UTC) Received: from [127.0.0.1] (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7907210EE95E; Mon, 26 Mar 2018 15:42:33 +0000 (UTC) Subject: Re: [PATCH] gdb/x86: Handle kernels using compact xsave format To: Andrew Burgess , gdb-patches@sourceware.org References: <20180314005707.9009-1-andrew.burgess@embecosm.com> From: Pedro Alves Message-ID: <785bd5ce-1e3e-228c-663f-87a3555adaee@redhat.com> Date: Mon, 26 Mar 2018 15:42:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180314005707.9009-1-andrew.burgess@embecosm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2018-03/txt/msg00532.txt.bz2 On 03/14/2018 12:57 AM, Andrew Burgess wrote: > > [snip excellent description] > > gdb/ChangeLog: > > * i387-tdep.c (i387_supply_xsave): Supply initial values when > registers have not been initialised by the kernel yet. > (i387_collect_xsave): Update xstate_bv after check if any control > registers have changed. Updating the control registers should > result in xstate_bv being updated. > - memcpy (FXSAVE_ADDR (tdep, regs, i), buf, 2); > + p = FXSAVE_ADDR (tdep, regs, i); > + if (memcmp (p, buf, 2) == 0) > + { > + xstate_bv |= X86_XSTATE_X87; > + memcpy (p, buf, 2); > + } I don't understand this though -- if memcmp returns 0, then p and buf hold the same bytes, so the memcpy is useless. I think you meant to do "memcmp ... != 0" ? Curious no test catches that. Thanks, Pedro Alves