From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MLH8Y-0002H4-MU for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:43:10 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MLH8T-0002FA-CL for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:43:09 -0400 Received: from [199.232.76.173] (port=53656 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MLH8T-0002F2-7K for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:43:05 -0400 Received: from gecko.sbs.de ([194.138.37.40]:23831) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MLH8S-0005Ze-Hx for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:43:04 -0400 Message-ID: <4A48C4DF.20407@siemens.com> Date: Mon, 29 Jun 2009 15:42:55 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <20090627075350.13376.17936.stgit@mchn012c.ww002.siemens.net> <20090627075351.13376.20106.stgit@mchn012c.ww002.siemens.net> <200906291402.00530.paul@codesourcery.com> In-Reply-To: <200906291402.00530.paul@codesourcery.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH 4/4] gdbstub: x86: Switch 64/32 bit registers dynamically List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paul Brook Cc: Anthony Liguori , qemu-devel@nongnu.org Paul Brook wrote: > On Saturday 27 June 2009, Jan Kiszka wrote: >> Commit 56aebc891674cd2d07b3f64183415697be200084 changed gdbstub in way >> that debugging 32 or 16-bit guest code is no longer possible with qemu >> for x86_64 guest CPUs. Since that commit, qemu only provides registers >> sets for 64-bit, forcing current and foreseeable gdb to also switch its >> architecture to 64-bit. And this breaks if the inferior is 32 or 16 bit. >> >> 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. So what do you suggest for fixing this bug? Do you have a patch at hand to fix gdb before 7.0? And a solution for older gdbs? Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux