From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 128519 invoked by alias); 12 May 2015 16:00:13 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 128504 invoked by uid 89); 12 May 2015 16:00:12 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.6 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-ob0-f172.google.com Received: from mail-ob0-f172.google.com (HELO mail-ob0-f172.google.com) (209.85.214.172) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Tue, 12 May 2015 16:00:11 +0000 Received: by obcus9 with SMTP id us9so9082261obc.2 for ; Tue, 12 May 2015 09:00:09 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.202.223.131 with SMTP id w125mr11782595oig.108.1431446409277; Tue, 12 May 2015 09:00:09 -0700 (PDT) Received: by 10.76.54.14 with HTTP; Tue, 12 May 2015 09:00:09 -0700 (PDT) In-Reply-To: References: <20150511212331.GA1838@intel.com> <5551F4E70200007800079575@mail.emea.novell.com> <55520C440200007800079718@mail.emea.novell.com> <555216370200007800079773@mail.emea.novell.com> <5552318402000078000798A8@mail.emea.novell.com> <555233B602000078000798EF@mail.emea.novell.com> <555235930200007800079911@mail.emea.novell.com> Date: Tue, 12 May 2015 16:00:00 -0000 Message-ID: Subject: Re: [committed, PATCH] Remove Disp16|Disp32 from 64-bit direct branches From: "H.J. Lu" To: Michael Matz Cc: Jan Beulich , Binutils Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2015-05/txt/msg00100.txt.bz2 On Tue, May 12, 2015 at 8:47 AM, Michael Matz wrote: > Hi, > > On Tue, 12 May 2015, H.J. Lu wrote: > >> > Actually also that one is correctly printed I think (from a hello world >> > main, where I added a jmprel16 +0): >> > >> > 000000000040055c
: >> > 40055c: 55 push %rbp >> > 40055d: 48 89 e5 mov %rsp,%rbp >> > 400560: 48 83 ec 30 sub $0x30,%rsp >> > 400564: c6 45 d1 00 movb $0x0,-0x2f(%rbp) >> > 400568: c6 45 d0 61 movb $0x61,-0x30(%rbp) >> > 40056c: 48 8d 45 d0 lea -0x30(%rbp),%rax >> > 400570: 48 89 c2 mov %rax,%rdx >> > 400573: be 44 06 40 00 mov $0x400644,%esi >> > 400578: 66 e9 00 00 jmpw 57c <_init-0x3ffe8c> >> > >> > 000000000040057c : >> > 40057c: bf 52 06 40 00 mov $0x400652,%edi >> > ... >> > >> > It shows that rip is going to be truncated. >> > >> >> This is the same issue as >> >> https://sourceware.org/bugzilla/show_bug.cgi?id=18386 >> >> On Intel processors, 0x66 prefix before direct 32-bit unconditional >> call/jmp is ignored. Whatever we do is wrong on AMD or Intel >> processors. > > Well, in that case I'd say the correct thing to do is to _not_ do any This is NO correct thing to do. > change, but rather let bintils work like it always did and resolve the > above bug report as WONTFIX (or unfixable or something). > > > Ciao, > Michael. -- H.J.