AESNI driver and fpu_kern KPI

Kostik Belousov kostikbel at
Sat May 15 11:41:57 UTC 2010

On Sat, May 15, 2010 at 01:04:36PM +0200, Marius Strobl wrote:
> On Sat, May 15, 2010 at 01:04:01PM +0300, Kostik Belousov wrote:
> > 
> > I am interested in the problem reports and reviews. Maintainers of
> > !x86-oids are welcome to provide feedback whether they feel that
> > proposed KPI could be implemented on their architectures, or what
> > modifications they consider as needed to be able to implement
> > it.
> > 
> FYI, sparc64 doesn't need such a KPI as it supports using the FPU
> in kernel unconditionally for ages.

How is this done on sparc64 ? Is PSTATE.PEF cleared on kernel entry,
or FPU is disabled ?

When I researched the problem space, I noted that windows on amd64
also provides an unrestricted access to XMM, while not on i386:
It seems that windows unconditionally set CR0.TS on kernel-mode
entry from usermode.
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