linux-kernel - Re: [PATCH v6 03/27] x86, boot: move verify_cpu.S and no

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Message-ID: <20121219205732.GI24895@liondog.tnic>
Date:	Wed, 19 Dec 2012 21:57:32 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Matt Fleming <matt.fleming@...el.com>
Subject: Re: [PATCH v6 03/27] x86, boot: move verify_cpu.S and no_longmode
 after 0x200

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@...en8.de> 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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