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

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

>From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>Sent: 2006年4月24日 18:03
>
>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.

Nice to know it working now. Actually I didn't realize it as an 
AP-only issue and you gave it a final shoot. :-)

Thanks,
Kevin

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