Linus Torvalds wrote:
> 
> On Fri, 19 Apr 2002, Brian Gerst wrote:
> 
>>Here's a patch to do just that.  It initializes the saved state in the
>>task struct and falls through to restore_fpu().
> 
> 
> One issue is whether we _can_ restore a "generated" image like this: it's
> entirely possible that Intel might save away internal CPU shadow data in
> the save-state structure, and future CPU's might be unhappy about loading
> data that doesn't conform to what the CPU would save.
> 
> That said, the same issue is certainly true for just doing "xorps", since
> that will not clear any potential future CPU state.
> 
> I get this feeling that Intel screwed up on specifying how to initialize
> this whole state.
> 
> 		Linus
> 

I don't know about Intel, but the Athlon doesn't appear to save anything 
in the "reserved" areas.  The values that I use to initialize the state 
are from what is saved after loading the stack with zeroes (fldz) and 
then doing finit.  I have samples of the saved state from a P2, a K6-2, 
and an Athlon XP.

Attached is a revised patch.  I had the cpu_has_xmm test wrong.

-- 

						Brian Gerst