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SubjectRe: [PATCH] Use correct x86 reboot vector
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Matt Mackall <mpm@selenic.com> writes:

> There's a missing piece of behavior here that's probably fatal.
> Namely, the next time the CS descriptor is loaded, even with the same
> value, the high bits are lost. So, for example, if you're running BIOS
> out of ROM, decompressing it into the top of 20-bit address space,
> then long jumping to your uncompressed code, you don't want to find
> yourself back in ROM.
>
> Perhaps there's a trick that can be played with loading the descriptor
> into CS and then clearing the descriptor table without flushing, but it
> sounds rather dubious..

If PE is really disabled that should bit should come for free. And it
is why it is so hard to fake this behavior.

Eric
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