From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265732AbUBLHHZ (ORCPT ); Thu, 12 Feb 2004 02:07:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266165AbUBLHHZ (ORCPT ); Thu, 12 Feb 2004 02:07:25 -0500 Received: from ns.suse.de ([195.135.220.2]:14513 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S265732AbUBLHHX (ORCPT ); Thu, 12 Feb 2004 02:07:23 -0500 Date: Thu, 12 Feb 2004 09:33:49 +0100 From: Andi Kleen To: George Anzinger Cc: amitkale@emsyssoft.com, akpm@osdl.org, pavel@ucw.cz, linux-kernel@vger.kernel.org, piggy@timesys.com, trini@kernel.crashing.org, mludvig@suse.cz Subject: Re: kgdb support in vanilla 2.6.2 Message-Id: <20040212093349.3be06202.ak@suse.de> In-Reply-To: <402AD815.6050004@mvista.com> References: <20040204230133.GA8702@elf.ucw.cz.suse.lists.linux.kernel> <20040204155452.49c1eba8.akpm@osdl.org.suse.lists.linux.kernel> <200402052320.04393.amitkale@emsyssoft.com> <20040206032054.3fd7db8d.ak@suse.de> <40295388.5080901@mvista.com> <20040213204227.0db612f7.ak@suse.de> <402AD815.6050004@mvista.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Feb 2004 17:34:13 -0800 George Anzinger wrote: > > The latest binutils should support .cfi_* for i386 too. I don't see much sense > > in making the code more ugly just for staying backwards compatible with older versions for the > > debug case (without CONFIG_DEBUG_INFO it should be compatible though). > > You need a fairly new gdb too anyways for it. > > Well, yes, the CVS version I mentioned in my patch is needed as I found a bug in > the expression analizer. I am NOT trying to say compatable with old tools. I > AM trying to do something the CURRENT tools make hard to impossible. > > The problem with the gas CFI support is that it does not provide a way to define > CFI expressions which are needed to determine if the CFI address should be zero > (i.e. the return is to user space) or the current adjusted stack address. Michal, can you comment? > I suppose the open ended .cfi_ thing could be used but it requires that you > compute your own sleb128 and uleb128 values. It is also not clear how you tell > this thing if you want a word or a half word as the dwarf2 spec requires. More > info on this would be very "nice". I really would like to do this with out the > dwarf2 macros, but, please understand, one of the main reasons for the effort > was to tie off the bottom of the stack and that seems to require an expression > capability for the asm code in entry.S. The one issue that required expression support on x86-64 (switching between the interrupt stack and the process stack) was handled by a dummy base register with a single ifdef. This turned out to be relatively clean. -Andi