Re: [Xen-ia64-devel] PATCH: [resent] cleanup + fph handling

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Lundi 24 Avril 2006 11:51, Tristan Gingold a écrit :
> Le Lundi 24 Avril 2006 11:06, Tian, Kevin a écrit :
> > From: Tristan Gingold
> >
> > >Sent: 2006年4月24日 16:40
> > >Hi,
> > >
> > >
> > >this patch moves switch_to macro from xensystem.h and put its body
> > >directly in
> > >context_switch.  FP saved and restore is slighly optimized: fph is
> > > *still* enabled and not anymore disabled.
> > >
> > >Misc cleanup.
> > >
> > >Note: not enabling fph before saving fph in context switch does not
> > > work. I
> > >will look on this issue.  However,  I think it is worth adding this
> > > patch.
> >
> > If you failed at the first context switch, the possible cause is in
> > head.S where psr.dfh is initialized as disabled for idle domain. Then the
> > first time when you switch from idle to domain0, disabled fp fault occurs
> > unless you explicitly enable psr.dfh like in your patch. This is one
> > place where psr value doesn't get from hardware exception.
>
> Oops, this may be correct for all the AP cpus!
This now works.

Thank you Kevin, you were on the right way!

Tristan.


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