Re: [PATCH RFC 2/5] x86,fpu: delay FPU register loading until switch to userspace

From: Rik van Riel
Date: Sat Oct 01 2016 - 20:54:02 EST

On Sat, 2016-10-01 at 16:44 -0700, Andy Lutomirski wrote:
> On Sat, Oct 1, 2016 at 1:31 PM,ÂÂ<riel@xxxxxxxxxx> wrote:
> >
> > +static inline void switch_fpu_finish(void)
> > Â{
> > +ÂÂÂÂÂÂÂset_thread_flag(TIF_LOAD_FPU);
> > Â}
> I can imagine this causing problems with kernel code that accesses
> current's FPU state, e.g. get_xsave_field_ptr().Â

That makes me wonder, what test programs do people have
to verify the correctness of the FPU switching code?

I have a few floating point benchmarks that check
the results for correctness, but nothing that adds in
signals, for example.

What do people use?

All Rights Reversed.

Attachment: signature.asc
Description: This is a digitally signed message part