Subject: [osol-code] XHAT
From: Ivan
Date: 2006-03-22 21:33:26
Hi,
Does somebody know the purpose of Xhat in the kernel?
Thanks in advance
With kindest regards,
Ivan
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From: Eric Lowe
Date: 2006-03-22 22:07:47
XHAT is a giant kludge which was created for the Zulu graphics driver,
which is its only consumer. The Zulu device was created back when Sun was
still trying to do their own graphics cards :) and it was special because
it had a full-blown MMU onboard. XHAT allowed it to directly access the
kernel's virtual to physical mappings in a safe manner, which can't be
done through the usual methods like the DDI.
- Eric
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From: Nils Nieuwejaar
Date: 2006-03-23 00:23:48
On Wed 03/22/06 at 15:07 PM, <email removed> wrote:
> XHAT is a giant kludge which was created for the Zulu graphics driver,
> which is its only consumer. The Zulu device was created back when Sun was
> still trying to do their own graphics cards :) and it was special because
> it had a full-blown MMU onboard. XHAT allowed it to directly access the
> kernel's virtual to physical mappings in a safe manner, which can't be
> done through the usual methods like the DDI.
To which I would add: please don't use it. Someday the hardware will be
EOLed, allowing us to excise XHAT - assuming it doesn't pick up any
consumers before then.
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From: Eric Lowe
Date: 2006-03-23 00:50:35
Nils Nieuwejaar wrote:
> To which I would add: please don't use it. Someday the hardware will be
> EOLed, allowing us to excise XHAT - assuming it doesn't pick up any
> consumers before then.
Precisely. I keep a can of gasoline, matches, chocolate, marshmallows, and
graham crackers under my desk just for occasions like torching XHAT. :>
- Eric
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