linux-kernel - Re: [PATCH] x86: relocate_kernel - use predefined PAGE

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Date:	Sat, 22 Mar 2008 00:02:28 +0300
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: relocate_kernel - use predefined PAGE_SIZE
	instead of own alias

[H. Peter Anvin - Fri, Mar 21, 2008 at 01:50:33PM -0700]
> Cyrill Gorcunov wrote:
>> [H. Peter Anvin - Fri, Mar 21, 2008 at 01:18:13PM -0700]
>>> Cyrill Gorcunov wrote:
>>>> This patch does clean up relocate_kernel_(32|64).S a bit by getting rid
>>>> of local PAGE_ALIGNED macro. We should use well-known PAGE_SIZE instead
>>>> Signed-off-by: Cyrill Gorcunov <gorcunov@...il.com>
>>> Looks good!
>>>
>>> 	-hpa
>>>
>> Thanks Peter for review, btw we have in relocate_kernel_32.S
>> 188:	movl	%cr4, %eax
>> 189:	andl	$0, %eax
>> 190:	movl	%eax, %cr4
>> but maybe would be better just replace it with
>> 	xorl	%eax, %eax
>> 	movl	%eax, %cr4
>> or there is some nonobvious reason not to do so?
>
> The only case I can think of would be if the code expects to patch the 
> zero, but even then it'd be cantankerous, because gas will optimize that 
> zero down to a single byte.
>
> So, no :)
>
> 	-hpa
>
well, Peter, it seems I'm too tired on this week and misinterpred
your message, my prev message with text "ah..." is wrong, i'll patch
this code later (almost sleeping now ;)

		- Cyrill -
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