From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
To: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
Cc: "Willy Tarreau"
<wtarreau-Dj75qbTlC0E76Z2rM5mHXA@public.gmane.org>,
"Dirk Hohndel" <hohndel-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
"Frédéric 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>,
"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
X86-ML <x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"Ahmed S. Darwish"
<darwish.07-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"Ingo Molnar" <mingo-H+wXaHxf7aLQT0dZR+AlfA@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>
Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic
Date: Thu, 27 Jan 2011 07:47:54 -0800 [thread overview]
Message-ID: <m1aaimxs9h.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20110127114113.GB20279-X9Un+BFzKDI@public.gmane.org> (Ingo Molnar's message of "Thu, 27 Jan 2011 12:41:13 +0100")
Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org> writes:
> * H. Peter Anvin <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> wrote:
>
>> On 01/26/2011 06:00 AM, Ingo Molnar wrote:
>> >
>> >I mean, use the warm reset vector to truly reset the box.
>> >
>> >Then, once a stable known-good kernel boots, *that* kernel can then recover all the
>> >log data which is sitting in a well-known place in RAM, automatically and
>> >transparently.
>> >
>> >Basically a bit like kexec, just more convenient and it also goes through the BIOS
>> >warm reset, so it might work better than kexec ...
>> >
>>
>> The problem is that the BIOS will often wipe memory.
>
> Yes - but at least a long time ago there used to be modi of reboot when the BIOS did
> not do this. Whether that's possible at all with modern BIOSen is a
> big question ...
As I recall that was how you went from 32bit mode to 16bit real mode.
The issue is that mode never reset the hardware it simply changed the
cpu mode.
Eric
next prev parent reply other threads:[~2011-01-27 15:47 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-25 13:47 [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Ahmed S. Darwish
2011-01-25 13:51 ` [PATCH -next 1/2][RFC] x86: Saveoops: Switch to real-mode and call BIOS Ahmed S. Darwish
2011-01-25 17:26 ` H. Peter Anvin
2011-01-25 13:53 ` [PATCH -next 2/2][RFC] x86: Saveoops: Reserve low memory and register code Ahmed S. Darwish
2011-01-25 17:29 ` H. Peter Anvin
2011-01-26 9:04 ` Ahmed S. Darwish
2011-01-25 14:09 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Ingo Molnar
2011-01-25 15:08 ` Tejun Heo
2011-01-25 17:33 ` H. Peter Anvin
2011-01-26 11:44 ` Ahmed S. Darwish
2011-02-03 14:36 ` Pavel Machek
2011-02-03 15:28 ` H. Peter Anvin
2011-02-03 17:57 ` Ingo Molnar
2011-02-03 21:07 ` H. Peter Anvin
2011-01-25 15:36 ` Ahmed S. Darwish
2011-01-25 16:02 ` James Bottomley
2011-01-25 17:05 ` Ahmed S. Darwish
2011-01-25 17:20 ` James Bottomley
2011-01-25 22:10 ` Mark Lord
2011-01-25 22:16 ` Randy Dunlap
2011-01-25 22:45 ` Jeff Garzik
2011-01-25 22:58 ` H. Peter Anvin
2011-01-26 0:26 ` Jeff Garzik
2011-01-31 2:59 ` Rusty Russell
2011-01-31 10:45 ` Ingo Molnar
2011-01-25 17:32 ` Tony Luck
2011-01-25 17:36 ` H. Peter Anvin
2011-01-25 19:04 ` Jeff Garzik
2011-01-25 14:49 ` Tejun Heo
2011-01-28 7:59 ` Jan Ceuleers
2011-01-25 20:25 ` Linus Torvalds
[not found] ` <AANLkTinU0KYiCd4p=z+=ojbkeEoT2G+CAYvdRU02KJEn-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-01-26 12:49 ` Ahmed S. Darwish
2011-01-26 12:58 ` Ingo Molnar
[not found] ` <20110126125813.GA26952-X9Un+BFzKDI@public.gmane.org>
2011-01-26 13:34 ` Ahmed S. Darwish
2011-01-26 14:00 ` Ingo Molnar
[not found] ` <20110126140030.GB30064-X9Un+BFzKDI@public.gmane.org>
2011-01-27 4:35 ` H. Peter Anvin
[not found] ` <4D40F5FD.6090507-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2011-01-27 11:41 ` Ingo Molnar
[not found] ` <20110127114113.GB20279-X9Un+BFzKDI@public.gmane.org>
2011-01-27 15:47 ` Eric W. Biederman [this message]
[not found] ` <m1aaimxs9h.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2011-01-27 16:12 ` H. Peter Anvin
2011-01-26 23:07 ` Luck, Tony
[not found] ` <987664A83D2D224EAE907B061CE93D53019438EABF-osO9UTpF0URqS6EAlXoojrfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2011-01-26 23:16 ` Dave Jones
[not found] ` <20110126231620.GA14807-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-01-26 23:21 ` Luck, Tony
[not found] ` <20110126233033.GB14807@redhat.com>
[not found] ` <987664A83D2D224EAE907B061CE93D53019438EBB6@orsmsx505.amr.corp.intel.com>
[not found] ` <4D40F7F1.3020509@zytor.com>
[not found] ` <20110127120039.GD20279@elte.hu>
2011-01-27 18:35 ` Luck, Tony
[not found] ` <4D4197CB.9070201@zytor.com>
[not found] ` <20110127162429.GB26437@elte.hu>
2011-01-27 18:56 ` Luck, Tony
2011-01-27 1:09 ` Ahmed S. Darwish
[not found] ` <20110127021338.GA20334@redhat.com>
[not found] ` <20110127021338.GA20334-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-01-27 3:33 ` Ahmed S. Darwish
2011-01-27 4:44 ` H. Peter Anvin
[not found] ` <4D40F81E.1030009-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2011-01-27 5:26 ` Ahmed S. Darwish
2011-01-27 7:51 ` Eric W. Biederman
2011-02-02 11:13 ` Ahmed S. Darwish
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