Re: [BK-2.5] Move "used FPU status" into new non-atomic thread_info->status field.

From: David S. Miller (davem@redhat.com)
Date: Mon Mar 10 2003 - 13:56:59 EST

   From: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
   Date: Mon, 10 Mar 2003 18:20:35 +0000
           
Linus said, in a recent BK changelog:

           Also, fix x86 FP state after fork() by making sure the FP is unlazied
           _before_ we copy the state information. Otherwise, if a process did a
           fork() while holding the FP state lazily in the registers, the child
           would incorrectly unlazy bogus state.
   
At least on sparc{32,64}, we consider FPU state to be clobbered coming
into system calls, this eliminates a lot of hair wrt. FPU state
restoring in cases such as fork().

Are you preserving FPU state across fork() on x86? If so, what do you
think might rely on this?
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