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Message-ID: <3CC0B217.902@didntduck.org>
Date: Fri, 19 Apr 2002 20:11:03 -0400
From: Brian Gerst <bgerst@didntduck.org>
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To: Linus Torvalds <torvalds@transmeta.com>
CC: "H. Peter Anvin" <hpa@zytor.com>, andrea@suse.de, ak@suse.de,
        linux-kernel@vger.kernel.org, jh@suse.cz
Subject: Re: [PATCH] Re: SSE related security hole
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Linus Torvalds wrote:
> 
> On Fri, 19 Apr 2002, H. Peter Anvin wrote:
> 
>>Indeed.  Logically, FNINIT should have been extended to initialize it all -
>>- it is a security hole that it doesn't initialize MMX properly.
> 
> 
> Well, MMX should arguably be initialized with "emms", so the proper
> sequence migth be something like
> 
> 	if (sse)
> 		asm("emms");
> 	asm("fninit");
> 
> What does emms do to SSE2?
> 
> 		Linus
> 

All emms does is reset the tag word.  It doesn't touch the registers.

-- 

						Brian Gerst

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