From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id 08CF43858D35 for ; Wed, 26 Jul 2023 20:45:24 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 08CF43858D35 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=polymtl.ca Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=polymtl.ca Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 36QKjHIV010972 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Jul 2023 16:45:22 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 36QKjHIV010972 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=polymtl.ca; s=default; t=1690404322; bh=KG7t12TDnpt73h4cA8L4OzJ7ETDAiejQKEpXxc0WB2U=; h=Date:Subject:To:References:From:In-Reply-To:From; b=qPllHfiMDvB+8UtwCOVUJ+0nI/bvKTDt0MMgYK08tpxLBSVNl+x/RcntgNwkd+fNE UQ4nIsbo1opCkeyZ+YxexbI2MZR0ZfN9aZq1XFoWVAqKTDyT+kLDUQm5VxfJuNd+wT I24ayKggkkMWiCl0rtmTpTqcSI5NAbtT7srrulGo= Received: from [10.0.0.170] (modemcable238.237-201-24.mc.videotron.ca [24.201.237.238]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id 8B8191E00F; Wed, 26 Jul 2023 16:45:17 -0400 (EDT) Message-ID: <45c8bfbf-42d2-c9d9-d246-0ffd6fc4668c@polymtl.ca> Date: Wed, 26 Jul 2023 16:45:17 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 08/15] gdb: Update x86 Linux architectures to support XSAVE layouts. Content-Language: fr To: John Baldwin , gdb-patches@sourceware.org References: <20230714155151.21723-1-jhb@FreeBSD.org> <20230714155151.21723-9-jhb@FreeBSD.org> From: Simon Marchi In-Reply-To: <20230714155151.21723-9-jhb@FreeBSD.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Wed, 26 Jul 2023 20:45:18 +0000 X-Spam-Status: No, score=-3037.6 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_LOW,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_PASS,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c > index 554c1455a5f..f27efbb1d59 100644 > --- a/gdb/i386-linux-tdep.c > +++ b/gdb/i386-linux-tdep.c > @@ -638,45 +638,51 @@ static int i386_linux_sc_reg_offset[] = > 0 * 4 /* %gs */ > }; > > -/* Get XSAVE extended state xcr0 from core dump. */ > +/* See i386-linux-tdep.h. */ > > uint64_t > -i386_linux_core_read_xcr0 (bfd *abfd) > +i386_linux_core_read_xsave_info (bfd *abfd, x86_xsave_layout &layout) > { > asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate"); > - uint64_t xcr0; > + if (xstate == nullptr) > + return X86_XSTATE_SSE_MASK; > > - if (xstate) > + /* Check extended state size. */ > + size_t size = bfd_section_size (xstate); > + if (size < X86_XSTATE_AVX_SIZE) > + return X86_XSTATE_SSE_MASK; > + > + char contents[8]; > + if (! bfd_get_section_contents (abfd, xstate, contents, > + I386_LINUX_XSAVE_XCR0_OFFSET, 8)) > { > - size_t size = bfd_section_size (xstate); > - > - /* Check extended state size. */ > - if (size < X86_XSTATE_AVX_SIZE) > - xcr0 = X86_XSTATE_SSE_MASK; > - else > - { > - char contents[8]; > - > - if (! bfd_get_section_contents (abfd, xstate, contents, > - I386_LINUX_XSAVE_XCR0_OFFSET, > - 8)) > - { > - warning (_("Couldn't read `xcr0' bytes from " > - "`.reg-xstate' section in core file.")); > - return 0; > - } > - > - xcr0 = bfd_get_64 (abfd, contents); > - } > + warning (_("Couldn't read `xcr0' bytes from " > + "`.reg-xstate' section in core file.")); > + return X86_XSTATE_SSE_MASK; > } > - else > - xcr0 = 0; > + > + uint64_t xcr0 = bfd_get_64 (abfd, contents); > + > + if (!i387_set_xsave_layout (xcr0, size, layout)) > + return X86_XSTATE_SSE_MASK; > > return xcr0; > } I think I spotted a change of behavior in i386_linux_core_read_xsave_info, which has consequences down the line. If there's no .reg-xstate section, we would previously return xcr0 == 0, i386_linux_read_description would return nullptr, and we would choose between X87 and SSE based on .reg-xfp. After the patch, i386_linux_core_read_xsave_info returns SSE, meaning we'll never reach the point that checks for .reg-xfp. Maybe the first return (if there's not .reg-xstate section) should return 0? > > /* See i386-linux-tdep.h. */ > > +bool > +i386_linux_core_read_x86_xsave_layout (struct gdbarch *gdbarch, > + x86_xsave_layout &layout) > +{ > + if (i386_linux_core_read_xsave_info (core_bfd, layout) == X86_XSTATE_SSE_MASK) > + return false; > + > + return true; > +} Same as earlier, could be: return i386_linux_core_read_xsave_info (core_bfd, layout) != X86_XSTATE_SSE_MASK; ... although if i386_linux_core_read_xsave_info can return 0, we'd need to check for that too. Simon