From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 12080 invoked by alias); 30 Oct 2012 13:55:10 -0000 Received: (qmail 12033 invoked by uid 22791); 30 Oct 2012 13:55:07 -0000 X-SWARE-Spam-Status: No, hits=-3.3 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED,RP_MATCHES_RCVD,TW_YM X-Spam-Check-By: sourceware.org Received: from sibelius.xs4all.nl (HELO glazunov.sibelius.xs4all.nl) (83.163.83.176) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 30 Oct 2012 13:54:55 +0000 Received: from glazunov.sibelius.xs4all.nl (kettenis@localhost [127.0.0.1]) by glazunov.sibelius.xs4all.nl (8.14.5/8.14.3) with ESMTP id q9UDsgni010406; Tue, 30 Oct 2012 14:54:42 +0100 (CET) Received: (from kettenis@localhost) by glazunov.sibelius.xs4all.nl (8.14.5/8.14.3/Submit) id q9UDseOZ022173; Tue, 30 Oct 2012 14:54:40 +0100 (CET) Date: Tue, 30 Oct 2012 13:55:00 -0000 Message-Id: <201210301354.q9UDseOZ022173@glazunov.sibelius.xs4all.nl> From: Mark Kettenis To: palves@redhat.com CC: yao@codesourcery.com, hjl.tools@gmail.com, binutils@sourceware.org, gdb@sourceware.org In-reply-to: <508FCEC5.2020403@redhat.com> (message from Pedro Alves on Tue, 30 Oct 2012 12:57:41 +0000) Subject: Re: [rfc] bi-arch for x86-64 corefile. References: <1350881426-4945-1-git-send-email-yao@codesourcery.com> <508F3B88.8060701@codesourcery.com> <508F578F.8050807@codesourcery.com> <508FCA04.6010600@codesourcery.com> <508FCEC5.2020403@redhat.com> Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2012-10/txt/msg00115.txt.bz2 > Date: Tue, 30 Oct 2012 12:57:41 +0000 > From: Pedro Alves > > On 10/30/2012 12:37 PM, Yao Qi wrote: > > > This requires something different in configure options. In my previous patch, when configure i686-pc-linux-gnu-gdb to handle bi-arch, we run configure with '--enable-64-bit-bfd'. In current trunk (w/ your patch), we have to run configure with '--enable-targets=x86_64-pc-linux-gnu'. > > > > Copy gdb@ here to make sure GDB people are aware of this change, otherwise, configuring gdb with '--enable-64-bit-bfd' only still doesn't work for handling x86-64 corefile on x86 gdb. > > That sounds like an unnecessary restriction. A 32-bit GDB can debug a 64-bit > inferior with gdbserver just fine (it can also debug a 64-bit core), provided GDB > is built with --enable-64-bit-bfd. Yes, debugging a native 64-bit inferior won't > work due to ptrace limitations, but GDB's gcore command can generate cores > even when remote debugging w/ gdbserver. > > We have things like this, gdb/configure.tgt: > > i[34567]86-*-linux*) > # Target: Intel 386 running GNU/Linux > gdb_target_obs="i386-tdep.o i386-linux-tdep.o glibc-tdep.o i387-tdep.o \ > solib-svr4.o symfile-mem.o \ > linux-tdep.o linux-record.o" > if test "x$enable_64_bit_bfd" = "xyes"; then > # Target: GNU/Linux x86-64 > gdb_target_obs="amd64-tdep.o amd64-linux-tdep.o ${gdb_target_obs}" > fi > build_gdbserver=yes > ;; > > So it's be nice if bfd did the same in this case. Thus, I'd very much > prefer if --enable-64-bit-bfd was enough for making bi-arch corefiles > work. The problem is that the Linux core file support in bfd is still relies on native headers. Trying to "fix them up" for bi-arch like what's been done for the last couple of years on Linux is never going to give you true cross-debugging support.