From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17214 invoked by alias); 9 Oct 2012 16:35:11 -0000 Received: (qmail 17068 invoked by uid 22791); 9 Oct 2012 16:35:09 -0000 X-SWARE-Spam-Status: No, hits=-3.8 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,KHOP_RCVD_TRUST,KHOP_THREADED,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE,TW_AV X-Spam-Check-By: sourceware.org Received: from mail-ob0-f169.google.com (HELO mail-ob0-f169.google.com) (209.85.214.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 09 Oct 2012 16:35:03 +0000 Received: by mail-ob0-f169.google.com with SMTP id va7so5666652obc.0 for ; Tue, 09 Oct 2012 09:35:02 -0700 (PDT) MIME-Version: 1.0 Received: by 10.60.14.165 with SMTP id q5mr17002812oec.28.1349800502422; Tue, 09 Oct 2012 09:35:02 -0700 (PDT) Received: by 10.76.144.229 with HTTP; Tue, 9 Oct 2012 09:35:02 -0700 (PDT) In-Reply-To: <201210091547.q99FlrrT005368@glazunov.sibelius.xs4all.nl> References: <20121003154712.GH3028@adacore.com> <201210040657.q946vJlc006566@glazunov.sibelius.xs4all.nl> <201210081948.q98Jm3D7020175@glazunov.sibelius.xs4all.nl> <201210082022.q98KM82d014759@glazunov.sibelius.xs4all.nl> <201210082047.q98KlQ6V031554@glazunov.sibelius.xs4all.nl> <20121008210142.GA14305@gmail.com> <20121009153217.GA6936@gmail.com> <201210091539.q99Fdj3D027359@glazunov.sibelius.xs4all.nl> <201210091547.q99FlrrT005368@glazunov.sibelius.xs4all.nl> Date: Tue, 09 Oct 2012 16:35:00 -0000 Message-ID: Subject: Re: PING: PATCH: PR backtrace/14646: [x32] backtrace doesn't work From: "H.J. Lu" To: Mark Kettenis Cc: gdb-patches@sourceware.org Content-Type: text/plain; charset=ISO-8859-1 X-IsSubscribed: yes 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 X-SW-Source: 2012-10/txt/msg00155.txt.bz2 On Tue, Oct 9, 2012 at 8:47 AM, Mark Kettenis wrote: >> Date: Tue, 9 Oct 2012 17:39:45 +0200 (CEST) >> From: Mark Kettenis >> >> > Date: Tue, 9 Oct 2012 08:32:17 -0700 >> > From: "H.J. Lu" >> > >> > On Mon, Oct 08, 2012 at 02:01:42PM -0700, H.J. Lu wrote: >> > > On Mon, Oct 08, 2012 at 10:47:26PM +0200, Mark Kettenis wrote: >> > > > > Date: Mon, 8 Oct 2012 13:38:21 -0700 >> > > > > From: "H.J. Lu" >> > > > > >> > > > > On Mon, Oct 8, 2012 at 1:22 PM, Mark Kettenis wrote: >> > > > > >> Date: Mon, 8 Oct 2012 13:04:03 -0700 >> > > > > >> From: "H.J. Lu" >> > > > > >> >> > > > > >> On Mon, Oct 8, 2012 at 12:48 PM, Mark Kettenis wrote: >> > > > > >> >> Date: Thu, 4 Oct 2012 06:57:22 -0700 >> > > > > >> >> From: "H.J. Lu" >> > > > > >> >> >> > > > > >> >> On Wed, Oct 3, 2012 at 11:57 PM, Mark Kettenis wrote: >> > > > > >> >> > >> > > > > >> >> > Perhaps the user-regs.c mechanism can be used to establish eip -> pc >> > > > > >> >> > and esp -> sp mappings? >> > > > > >> >> >> > > > > >> >> It doesn't help as long as gdbarch_pc_regnum/gdbarch_sp_regnum >> > > > > >> >> are used for both frame pc/sp value and unwind pc/sp value. For x32, >> > > > > >> >> we want eip/esp for frame pc/sp value and rip/rsp for unwind pc/sp >> > > > > >> >> value. >> > > > > >> > >> > > > > >> > That probably means we need to set gdbarch_pc_regnum (and >> > > > > >> > gdbarch_sp_regnum) to -1 for x32. >> > > > > >> >> > > > > >> We can't set gdbarch_pc_regnum/gdbarch_sp_regnum to -1: >> > > > > >> >> > > > > >> >> > > > > >> GNU gdb (GDB) 7.5.50.20121008-cvs >> > > > > >> Copyright (C) 2012 Free Software Foundation, Inc. >> > > > > >> License GPLv3+: GNU GPL version 3 or later >> > > > > >> This is free software: you are free to change and redistribute it. >> > > > > >> There is NO WARRANTY, to the extent permitted by law. Type "show copying" >> > > > > >> and "show warranty" for details. >> > > > > >> This GDB was configured as "x86_64-unknown-linux-gnu". >> > > > > >> For bug reporting instructions, please see: >> > > > > >> ... >> > > > > >> Reading symbols from >> > > > > >> /export/build/gnu/glibc-x32/build-x86_64-linux/elf/sln...done. >> > > > > >> (gdb) b main >> > > > > >> Breakpoint 1 at 0x400c20: file sln.c, line 50. >> > > > > >> (gdb) r >> > > > > >> Starting program: /export/build/gnu/glibc-x32/build-x86_64-linux/elf/sln >> > > > > >> /export/gnu/import/git/gdb/gdb/regcache.c:1062: internal-error: >> > > > > >> regcache_read_pc: Unable to find PC >> > > > > >> A problem internal to GDB has been detected, >> > > > > >> further debugging may prove unreliable. >> > > > > >> Quit this debugging session? (y or n) >> > > > > > >> > > > > > Well, obviously you'll need to implement gdbarch_read_pc() for this to >> > > > > > work. And probably a few more gdbarch methods. >> > > > > >> > > > > What do we gain by setting gdbarch_pc_regnum/gdbarch_sp_regnum >> > > > > to -1? PC and SP are RIP and RSP for x32. We need them for >> > > > > stack unwind. The only unusual part is they are 64-bit although >> > > > > x32 is a 32-bit environment. How about this change? >> > > > >> > > > Did you even try that change? >> > > > >> > > > > diff --git a/gdb/features/i386/x32-core.xml b/gdb/features/i386/x32-core.xml >> > > > > index 1e41417..392ce24 100644 >> > > > > --- a/gdb/features/i386/x32-core.xml >> > > > > +++ b/gdb/features/i386/x32-core.xml >> > > > > @@ -34,7 +34,7 @@ >> > > > > >> > > > > >> > > > > >> > > > > - >> > > > > + >> > > > > >> > > > > >> > > > > >> > > > > @@ -44,7 +44,7 @@ >> > > > > >> > > > > >> > > > > >> > > > > - >> > > > > + >> > > > > >> > > > > >> > > > > >> > > >> > > Here is the patch I tried. It fixes PR backtrace/14646 and PR gdb/14647. >> > > >> > > >> > > H.J. >> > > --- >> > > 2012-10-08 H.J. Lu >> > > >> > > PR backtrace/14646 >> > > PR gdb/14647 >> > > * amd64-tdep.c (amd64_x32_init_abi): Don't set sp_regnum_from_eax >> > > nor pc_regnum_from_eax. >> > > * i386-tdep.c (i386_gdbarch_init): Don't use sp_regnum_from_eax >> > > nor pc_regnum_from_eax. >> > > * i386-tdep.h (gdbarch_tdep): Remove sp_regnum_from_eax and >> > > pc_regnum_from_eax. >> > > * features/i386/x32-core.xml: Use data_ptr on rsp and use >> > > code_ptr on rip. >> > > * features/i386/x32-avx-linux.c: Regenerated. >> > > * features/i386/x32-avx.c: Likewise. >> > > * features/i386/x32-linux.c: Likewise. >> > > * features/i386/x32.c: Likewise. >> > > >> > >> > X32 needs to set RSP/RIP to 32-bit. Othewise, it won't work with gdbserver >> > since gdbserver will send 64-bit RSP/RIP while gdb sets size of RSP/RIP >> > to pointer size, which is 32-bit for x32. It works for x32 since the >> > upper 32bits of RSP/RIP are always zero for x32. OK for trunk and 7.5 >> > branch. >> >> At least you figured out that your previous diff didn't work all by >> yourself. How about actually testing your diffs *before* you mail >> them out? > > Oh, and even if this diff accidentally happens to work, it is a really > bad idea. You won't be able to diagnose problems caused by one of the > upper 32 bits getting set in %rsp or %rip. > I will see if I can break RSP/RIP into ESP/EIP and HSP/HIP, similar to YMM, for x32. -- H.J.