From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MLHVs-0002c9-DV for qemu-devel@nongnu.org; Mon, 29 Jun 2009 10:07:16 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MLHVn-0002TL-Ds for qemu-devel@nongnu.org; Mon, 29 Jun 2009 10:07:15 -0400 Received: from [199.232.76.173] (port=35879 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MLHVn-0002T4-8q for qemu-devel@nongnu.org; Mon, 29 Jun 2009 10:07:11 -0400 Received: from mx20.gnu.org ([199.232.41.8]:33006) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MLHVm-0005jh-KF for qemu-devel@nongnu.org; Mon, 29 Jun 2009 10:07:10 -0400 Received: from mail.codesourcery.com ([65.74.133.4]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MLHVl-0007r8-Nn for qemu-devel@nongnu.org; Mon, 29 Jun 2009 10:07:10 -0400 From: Paul Brook Subject: Re: [Qemu-devel] Re: [PATCH 4/4] gdbstub: x86: Switch 64/32 bit registers dynamically Date: Mon, 29 Jun 2009 15:07:04 +0100 References: <20090627075350.13376.17936.stgit@mchn012c.ww002.siemens.net> <200906291402.00530.paul@codesourcery.com> <4A48C4DF.20407@siemens.com> In-Reply-To: <4A48C4DF.20407@siemens.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200906291507.05278.paul@codesourcery.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Jan Kiszka , Anthony Liguori > >> No question, this is a gdb issue. But, as it was confirmed in several > >> discusssions with gdb people, it is a non-trivial thing to fix. So until > >> qemu finds a gdb version attach with a rework x86 support, we have to > >> work around it by switching the register layout as the guest switches > >> its execution mode between 16/32 and 64 bit. > > > > I still object to this patch. Especially as there's no indication that > > it's a harroble hack to workaround broken GDB. > > Sorry, last sentence doesn't parse for me. You've just deliberately broken the qemu gdbstub. After your patch it is impossible to debug mixed 32/64-bit code. > So what do you suggest for fixing this bug? Fix gdb. > Do you have a patch at hand to fix gdb before 7.0? No. I'm unconvinced by any argument that requires a specific GDB version. You've known about this bug for a long time now. > And a solution for older gdbs? If you really care about old gdb, then you get to backport the changes. Paul