iwmmxt signal frame handling

[Arnd Bergmann]

On Friday 15 October 2010 20:38:15 Nicolas Pitre wrote:
> Hard to confirm.  The only way not to have TIF_USING_IWMMXT set is to 
> use old pre-EABI binaries, which are relying on the kernel emulated FPA 
> instructions for floating point, and nothing in those days might have 
> cared about extensions to the ucontext layout at all, or even have used 
> iwmmxt.  While this is a correctness fix, in practice this never 
> mattered.

Ok, good to know.
 
> And we're talking about mixed ABI environments which existed many years 
> ago, like prior the Git era.  Hardly a stable tree candidate.

Yes, that's pretty clear then. I had assumed the TIF flag meant that
a particular process had been using IWMMXT, not that it was allowed
to do them.

Thanks for the explanation,

	Arnd