From: ebiederm@xmission.com (Eric W. Biederman)
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Use correct x86 reboot vector
Date: 11 May 2003 13:12:51 -0600 [thread overview]
Message-ID: <m1smrl5mbw.fsf@frodo.biederman.org> (raw)
In-Reply-To: <Pine.LNX.4.50.0305111119590.7563-100000@blue1.dev.mcafeelabs.com>
Davide Libenzi <davidel@xmailserver.org> writes:
> On Sun, 11 May 2003, Eric W. Biederman wrote:
>
> > The remapping is quite common but it usually happens that after bootup:
> > 0xf0000-0xfffff is shadowed RAM. While 0xffff0000-0xffffffff still points
> > to the rom chip.
> >
> > Now if someone could tell me how to do a jump to 0xffff0000:0xfff0 in real
> > mode I would find that very interesting.
>
> Have you ever heard about unreal mode ? But I do not think that a reset
> has to start over there. I do not think that exist hw/sw that expect that
> reset address to be 0xfffffff0 instead of 0x000ffff0, since they map the
> same content.
There is some software at least that knows the difference. I have seen short
jumps in a couple of BIOS's. But a reset is very different from a
reboot. As memory must be reinitialized etc. So I think going to
0xffff0000:0xfff0 would be a very bad idea if the intent is to get a
reliable reboot.
Eric
next prev parent reply other threads:[~2003-05-11 19:03 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-10 2:56 [PATCH] Use correct x86 reboot vector Andi Kleen
2003-05-10 3:35 ` CaT
2003-05-10 3:58 ` H. Peter Anvin
2003-05-10 14:49 ` Alan Cox
2003-05-10 16:17 ` Jamie Lokier
2003-05-10 18:47 ` Jos Hulzink
2003-05-11 18:01 ` Eric W. Biederman
2003-05-11 17:24 ` Alan Cox
2003-05-11 19:04 ` Eric W. Biederman
2003-05-12 5:48 ` [PATCH] always shutdown on the bootstrap processor Eric W. Biederman
2003-05-10 16:15 ` [PATCH] Use correct x86 reboot vector Jamie Lokier
2003-05-10 17:09 ` Randy.Dunlap
2003-05-10 19:41 ` Jos Hulzink
2003-05-10 18:10 ` Jamie Lokier
2003-05-10 20:55 ` Jos Hulzink
2003-05-11 3:50 ` Linus Torvalds
2003-05-11 9:37 ` Jos Hulzink
2003-05-11 14:01 ` Jamie Lokier
2003-05-11 17:38 ` Davide Libenzi
2003-05-11 17:56 ` Eric W. Biederman
2003-05-11 18:23 ` Davide Libenzi
2003-05-11 19:12 ` Eric W. Biederman [this message]
2003-05-12 15:36 ` Maciej W. Rozycki
2003-05-13 6:35 ` H. Peter Anvin
2003-05-11 18:38 ` Linus Torvalds
2003-05-11 19:00 ` Matt Mackall
2003-05-11 19:16 ` Eric W. Biederman
2003-05-12 1:07 ` H. Peter Anvin
2003-05-11 19:10 ` Eric W. Biederman
2003-05-11 18:43 ` Christer Weinigel
2003-05-11 20:22 ` wingel
2003-05-11 20:26 ` Davide Libenzi
2003-05-11 17:54 ` Eric W. Biederman
-- strict thread matches above, loose matches on Subject: below --
2003-05-13 12:49 Chuck Ebbert
2003-05-13 18:45 ` H. Peter Anvin
2003-05-13 19:04 ` Richard B. Johnson
2003-05-13 19:27 ` H. Peter Anvin
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