From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263158AbUB0WBr (ORCPT ); Fri, 27 Feb 2004 17:01:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263031AbUB0V7b (ORCPT ); Fri, 27 Feb 2004 16:59:31 -0500 Received: from gateway-1237.mvista.com ([12.44.186.158]:5106 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S263169AbUB0V6T (ORCPT ); Fri, 27 Feb 2004 16:58:19 -0500 Message-ID: <403FBD6D.8040706@mvista.com> Date: Fri, 27 Feb 2004 13:58:05 -0800 From: George Anzinger Organization: MontaVista Software User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Piet Delaney CC: Andi Kleen , "Amit S. Kale" , akpm@osdl.org, pavel@ucw.cz, linux-kernel@vger.kernel.org, piggy@timesys.com, trini@kernel.crashing.org Subject: Re: kgdb support in vanilla 2.6.2 References: <20040204230133.GA8702@elf.ucw.cz.suse.lists.linux.kernel> <20040204155452.4 9c1eba8.akpm@osdl.org.suse.lists.linux.kernel> <200402052320.04393.amitkale@emsyssoft.com> <20040206032054.3fd7db8d.ak@suse.de> <40295388.5080901@mvista.com> <1077916151.3291.133.camel@www.piet.net> In-Reply-To: <1077916151.3291.133.camel@www.piet.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Piet Delaney wrote: > On Tue, 2004-02-10 at 13:56, George Anzinger wrote: > > I thought I'd poke around an AMD64 with etherbased kgdb on 2.6.*. > I just picked up a used AMD64 K8D Master-F MS-9131 and thought I'd > install Fedora Core 1 test1 and the latest kernel from kernel.org. > > It Might be interesting to try out a SuSE release also, I was wondering > if 9.0 from linuxiso.org might be best. > > Last I worked with your kgdb patch for 2.6 Andrew's mm patch had the > latest code; Is that still the case? I think so. I haven't look lately. I did send out an additional patch that only put in dwarft2 records in some of the asm code to allow better "bt" through the interrupt/exception frames. I don't know if he picked this up or not, but it does require using the cvs version of gdb. -g > > -piet > > >>Andi Kleen wrote: >> >>>On Thu, 5 Feb 2004 23:20:04 +0530 >>>"Amit S. Kale" wrote: >>> >>> >>> >>>>On Thursday 05 Feb 2004 8:41 am, Andi Kleen wrote: >>>> >>>> >>>>>Andrew Morton writes: >>>>> >>>>> >>>>>>need to take a look at such things and really convice ourselves that >>>>>>they're worthwhile. Personally, I'd only be interested in the basic >>>>>>stub. >>>>> >>>>>What I found always extremly ugly in the i386 stub was that it uses >>>>>magic globals to talk to the page fault handler. For the x86-64 >>>>>version I replaced that by just using __get/__put_user in the memory >>>>>accesses, which is much cleaner. I would suggest doing that for i386 >>>>>too. >>>> >>>>May be I am missing something obvious. When debugging a page fault handler if >>>>kgdb accesses an swapped-out user page doesn't it deadlock when trying to >>>>hold mm semaphore? >>> >>> >>>Modern i386 kernels don't grab the mm semaphore when the access is >= TASK_SIZE >>>and the access came from kernel space (actually I see x86-64 still does, but that's >>>a bug, will fix). You could only see a deadlock when using user addresses >>>and you already hold the mm semaphore for writing (normal read lock is ok). >>>Just don't do that. >>> >>> >>> >>> >>>>George has coded cfi directives i386 too. He can use them to backtrace past >>>>irqs stack. >>> >>> >>>Problem is that he did it without binutils support. I don't think that's a good >>>idea because it makes the code basically unmaintainable for normal souls >>>(it's like writing assembly code directly in hex) >> >>Well, bin utils, at this time, makes it even worse in that it does not support >>the expression syntax. Also, it is not asm but dwarf2 and it is written in, >>IMHO, useful macros (not hex :) >> >> >> >>-- >>George Anzinger george@mvista.com >>High-res-timers: http://sourceforge.net/projects/high-res-timers/ >>Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml >> >>- >>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>the body of a message to majordomo@vger.kernel.org >>More majordomo info at http://vger.kernel.org/majordomo-info.html >>Please read the FAQ at http://www.tux.org/lkml/ -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml