Re: [PATCH] Re: SSE related security hole

Brian Gerst
2002-04-20T00:13:29Z

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