mfpvr instruction: how to get processor version info from userland?

[Nathan Whitehorn]

On 11/25/13 08:26, Alexey Dokuchaev wrote:
> On Mon, Nov 25, 2013 at 08:07:24AM -0600, Nathan Whitehorn wrote:
>>> it seems that mfpvr should do the job, but it can only be called from
>>> kernel.  Linux emulates it so user-space can have access to the info; but
>>> in FreeBSD, its prototype is hidden under #ifdef _KERNEL :(
>>>
>>> i haven't yet made my way through this code, but have a quick question: is
>>> there a way to obtain mfpvr() value from userland (thru kernel catching
>>> the trap that the processor raises when a non-privileged program tries to
>>> execute it), or i have to write my own kld for that?  i also wonder why it
>>> was made privileged in the first place...  thanks,
>> You can use it fine from userland -- just copy the mfpvr() definition
>> our of the header file. The architecture makes it privileged for various
>> reasons (VM mobility for instance), but we emulate it.
> OK, i see.  Would it more sense to open it to userland (in header file)
> in this case?  Or there are reasons it's hidden behind #ifdef _KERNEL?
>
> ./danfe

The whole header file is meant for kernel-only. Moving this around might 
make some sense.
-Nathan