cpuctl(formely devcpu) patch test request

Hi, FreeBSD hackers!

Due to increasing requests to have a special device
to provide MSR reading/writing abilities in the base
system, it was decided to integrate sysutils/devcpu module
into the kernel. Given the fact there were no new bugs
found in devcpu for a long time (though I fixed several
while preparing patches;-)) this should not brake our
kernel entirely.

Basically, the patch[1] implements a new pseudo-device
cpuctl which provides interface to read/write machine-
specific registers, retrieve CPUID data and update
processor firmware (on P6+ and K8 cpus). All of this
operations are performed via simple ioctl interface.
Currently, only amd64 and i386 cpus are supported.

I'd like to ask all interested parties to review
the patch mentioned[1]. kib_at_ was kind enough
to review the work on early stages (thanks a lot!)
but there might be bugs that was not noticed yet.
Or you might have some points about the interface
and implementation - tell it now, before the code
hits the tree.

I plan to update the microcode update utility to
use the new interface when it will be committed.
devcpu module will be shipped for older FreeBSD
versions.

Thanks!

[1] http://www.SpringDaemons.com/stas/cpuctl.diff

-- 
Stanislav Sedov
ST4096-RIPE