Re: [PATCH v6 03/27] x86, boot: move verify_cpu.S and no_longmodeafter 0x200

From: Borislav Petkov
Date: Wed Dec 19 2012 - 15:57:27 EST


On Tue, Dec 18, 2012 at 07:44:55PM -0800, Yinghai Lu wrote:
> On Sat, Dec 15, 2012 at 9:06 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> > On Thu, Dec 13, 2012 at 02:01:57PM -0800, Yinghai Lu wrote:
> >> We are short of space before 0x200 that is entry for startup_64.
> >
> > And you're moving this down because of the couple of bytes the next
> > patch is adding? If so, then explain that here.
>
> better?
>
> ---
> Subject: [PATCH] x86, boot: move verify_cpu.S and no_longmode down
>
> We need to move some code with 32bit section in following patch:
>
> x86, boot: Move lldt/ltr out of 64bit code section
>
> but that will push startup_64 down from 0x200.
>
> According to hpa, we can not change startup_64 to other offset and
> that become ABI now.
>
> We could move function verify_cpu and no_longmode down, because
> verify_cpu is used via function call and no_longmode will not
> return.
> ---

Almost.

So this explains what you're doing but I'd like to know why?

Why do you need to free some more room between startup_32 and
startup_64? Do you need this room in another patch, maybe the next one:

"[PATCH v7 14/27] x86, boot: Move lldt/ltr out of 64bit code section"

Is that so? If yes, please write that in the commit message so that we
know why you're doing that change.

Thanks.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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