From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MLGUs-0002gK-Ml for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:02:10 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MLGUn-0002fT-VG for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:02:10 -0400 Received: from [199.232.76.173] (port=54015 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MLGUn-0002fQ-No for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:02:05 -0400 Received: from mx20.gnu.org ([199.232.41.8]:29775) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MLGUn-0006YK-9m for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:02:05 -0400 Received: from mail.codesourcery.com ([65.74.133.4]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MLGUl-0003k0-RQ for qemu-devel@nongnu.org; Mon, 29 Jun 2009 09:02:04 -0400 From: Paul Brook Date: Mon, 29 Jun 2009 14:01:59 +0100 References: <20090627075350.13376.17936.stgit@mchn012c.ww002.siemens.net> <20090627075351.13376.20106.stgit@mchn012c.ww002.siemens.net> In-Reply-To: <20090627075351.13376.20106.stgit@mchn012c.ww002.siemens.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200906291402.00530.paul@codesourcery.com> 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: Jan Kiszka Cc: Anthony Liguori , qemu-devel@nongnu.org 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. Paul