Re: [PATCH] Use correct x86 reboot vector

["H. Peter Anvin" <hpa@zytor.com>]

Followup to:  <m1smrl5mbw.fsf@frodo.biederman.org>
By author:    ebiederm@xmission.com (Eric W. Biederman)
In newsgroup: linux.dev.kernel
> 
> 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.
> 

I agree.

Jumping to 0xf000:0xfff0 is widely accepted to be a standard warm
reboot (as *should* an INIT, e.g. triplefault, be, as well -- make
sure A20 is enabled before tripping, though.)  For quite a few (most?)
BIOSes, the vector that is stored at 0xf000:0xfff0 in the running
(BIOS decompressed and shadowed) configuration is *not* the same as
the one at the RESET vector.

	-hpa
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