From: "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
To: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@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>,
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>,
"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@us.>
Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic
Date: Thu, 27 Jan 2011 08:12:45 -0800 [thread overview]
Message-ID: <4D41997D.5070206@zytor.com> (raw)
In-Reply-To: <m1aaimxs9h.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
On 01/27/2011 07:47 AM, Eric W. Biederman wrote:
>>
>> 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.
>
Quite correct. It doesn't just bypass the memory wipe, it bypasses the
entire POST.
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Willy Tarreau" <wtarreau@hera.kernel.org>,
"Dirk Hohndel" <hohndel@infradead.org>,
"Frédéric Weisbecker" <fweisbec@gmail.com>,
FBDEV-ML <linux-fbdev@vger.kernel.org>,
IDE-ML <linux-ide@vger.kernel.org>,
"Randy Dunlap" <rdunlap@xenotime.net>,
"James Bottomley" <James.Bottomley@suse.de>,
X86-ML <x86@kernel.org>,
"Ahmed S. Darwish" <darwish.07@gmail.com>,
"Ingo Molnar" <mingo@redhat.com>, "Ingo Molnar" <mingo@elte.hu>,
"Jeff Garzik" <jgarzik@pobox.com>,
"Vivek Goyal" <vgoyal@redhat.com>,
"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
Dirk.Hohndel@intel.com, "Borislav Petkov" <bp@alien8.de>,
"Dave Jones" <davej@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Mark Lord" <kernel@teksavvy.com>,
"Arjan van de Ven" <arjan@infradead.org>,
"Tony Luck" <tony.luck@intel.com>,
KEXEC-ML <kexec@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
"Haren Myneni" <hbabu@us.ibm.com>, "Tejun Heo" <tj@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Willy Tarreau" <w@1wt.eu>
Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic
Date: Thu, 27 Jan 2011 08:12:45 -0800 [thread overview]
Message-ID: <4D41997D.5070206@zytor.com> (raw)
In-Reply-To: <m1aaimxs9h.fsf@fess.ebiederm.org>
On 01/27/2011 07:47 AM, Eric W. Biederman wrote:
>>
>> 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.
>
Quite correct. It doesn't just bypass the memory wipe, it bypasses the
entire POST.
-hpa
_______________________________________________
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kexec@lists.infradead.org
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next prev parent reply other threads:[~2011-01-27 16:12 UTC|newest]
Thread overview: 75+ 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 12:49 ` Ahmed S. Darwish
2011-01-26 12:58 ` Ingo Molnar
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 13:34 ` Ahmed S. Darwish
2011-01-26 14:00 ` Ingo Molnar
2011-01-26 14:00 ` Ingo Molnar
[not found] ` <20110126140030.GB30064-X9Un+BFzKDI@public.gmane.org>
2011-01-27 4:35 ` H. Peter Anvin
2011-01-27 4:35 ` H. Peter Anvin
[not found] ` <4D40F5FD.6090507-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2011-01-27 11:41 ` Ingo Molnar
2011-01-27 11:41 ` Ingo Molnar
[not found] ` <20110127114113.GB20279-X9Un+BFzKDI@public.gmane.org>
2011-01-27 15:47 ` Eric W. Biederman
2011-01-27 15:47 ` Eric W. Biederman
[not found] ` <m1aaimxs9h.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2011-01-27 16:12 ` H. Peter Anvin [this message]
2011-01-27 16:12 ` H. Peter Anvin
2011-01-26 23:07 ` Luck, Tony
2011-01-26 23:07 ` Luck, Tony
2011-01-26 23:07 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon Luck, Tony
2011-01-26 23:07 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Luck, Tony
[not found] ` <987664A83D2D224EAE907B061CE93D53019438EABF-osO9UTpF0URqS6EAlXoojrfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2011-01-26 23:16 ` Dave Jones
2011-01-26 23:16 ` Dave Jones
[not found] ` <20110126231620.GA14807-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-01-26 23:21 ` Luck, Tony
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
2011-01-27 18:35 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon Luck, Tony
2011-01-27 18:35 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Luck, Tony
[not found] ` <4D4197CB.9070201@zytor.com>
[not found] ` <20110127162429.GB26437@elte.hu>
2011-01-27 18:56 ` Luck, Tony
2011-01-27 18:56 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon Luck, Tony
2011-01-27 18:56 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Luck, Tony
2011-01-27 1:09 ` Ahmed S. Darwish
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 3:33 ` Ahmed S. Darwish
2011-01-27 4:44 ` H. Peter Anvin
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 5:26 ` Ahmed S. Darwish
2011-01-27 7:51 ` Eric W. Biederman
2011-01-27 7:51 ` Eric W. Biederman
2011-02-02 11:13 ` Ahmed S. Darwish
2011-02-02 11:13 ` Ahmed S. Darwish
2011-02-02 11:13 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk Ahmed S. Darwish
2011-02-02 11:13 ` [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Ahmed S. Darwish
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