linux-kernel - Re: [tip:x86/asm] x86/i386: Make sure stack-protector segment base is cache aligned

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Date:	Fri, 04 Sep 2009 09:52:54 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	Tejun Heo <tj@...nel.org>, mingo@...hat.com,
	linux-kernel@...r.kernel.org, jeremy.fitzhardinge@...rix.com,
	stable@...nel.org, tglx@...utronix.de, mingo@...e.hu,
	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/asm] x86/i386: Make sure stack-protector segment base
 is cache aligned

On 09/04/2009 09:01 AM, Jeremy Fitzhardinge wrote:
>>>     
>> It's correct that it doesn't make any difference for access, only for load.
>>   
> 
> Well, to be completely precise, restore.  When returning to usermode,
> the "pop %seg" is slightly faster if you're restoring a null selector,
> which is typically the case for %fs as 32-bit usermode doesn't use it.
> 

That's a segment load...

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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