Re: [PATCH 1/3] x86, fpu: decouple non-lazy/eager fpu restore fromxsave

From: Suresh Siddha
Date: Fri Sep 07 2012 - 15:13:14 EST


On Fri, 2012-09-07 at 11:47 -0700, H. Peter Anvin wrote:
> On 09/07/2012 11:31 AM, Suresh Siddha wrote:
> >
> > +static inline void fx_finit(struct i387_fxsave_struct *fx)
> > +{
> > + memset(fx, 0, xstate_size);
> > + fx->cwd = 0x37f;
> > + if (cpu_has_xmm)
> > + fx->mxcsr = MXCSR_DEFAULT;
> > +}
> > +
>
> Incidentally, Al Viro asked a very good question the other day, which is
> why can't we just set mxcsr unconditionally here? I don't think any
> CPUs with FXSAVE and no MXCSR (Pentium II from Intel,
> Crusoe/TM-3xxx/5xxx from Transmeta, and presumably some of the K6
> generation from AMD) ever looked at this field.

Ok. We can do this as a separate patch.

thanks,
suresh

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