From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Ahmed S. Darwish" <darwish.07-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk
	upon panic
Date: Thu, 27 Jan 2011 07:26:39 +0200
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To: "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
Cc: Willy Tarreau <wtarreau-Dj75qbTlC0E76Z2rM5mHXA@public.gmane.org>, Dirk Hohndel <hohndel-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, FBDEV-ML <linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, IDE-ML <linux-ide-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Randy Dunlap <rdunlap-/UHa2rfvQTnk1uMJSBkQmQ@public.gmane.org>, James Bottomley <James.Bottomley-l3A5Bk7waGM@public.gmane.org>, X86-ML <x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>, Jeff Garzik <jgarzik-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>, Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>, Dirk.Hohndel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>, Dave Jones <davej-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Mark Lord <kernel-R6A+fiHC8nRWk0Htik3J/w@public.gmane.org>, Arjan van de Ven <arjan-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Tony Luck <tony.luck-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, KEXEC-ML <kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Haren Myneni <hbabu-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>, Eric Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>, Tejun
List-Id: linux-ide@vger.kernel.org

On Wed, Jan 26, 2011 at 08:44:14PM -0800, H. Peter Anvin wrote:
> On 01/26/2011 06:13 PM, Vivek Goyal wrote:
>>>
>>> - Use kexec/kdump. I wonder though, can kexec work on early panics? The
>>>    kind where the disk itself might not yet be initialized?
>>
>> As of today kexec/kdump does not work with early panics as kdump kernel
>> needs to be loaded in reserved memory and that action happens once the
>> first kernel has booted.
>>
>> There is so much to it that I really don't think that modifying bootloaders to
>> do all that might not trivial and more importantly I think it probably is not
>> worth the effort.
>>
>
> It's really not all that hard, actually.
>

Nice, I'll try prototyping this using syslinux and kexec: this seems the
safest path so far. Further details are in my first reply to Vivek.

> 	-hpa

thanks,

-- 
Darwish
http://darwish.07.googlepages.com