[PATCH] PowerPC - Add a function to read the Time Base frequency

[Ryan S. Arnold]

On Tue, Sep 25, 2012 at 2:31 PM, Carlos O'Donell
<carlos@systemhalted.org> wrote:
> On Tue, Sep 25, 2012 at 1:03 PM, Ryan Arnold <rsa@us.ibm.com> wrote:
>>> This looks good to me, I don't see anything wrong.
>>>
>>> Thanks for adding a testcase *and* documentation!
>>>
>>> Ryan should review this as power maintainer.
>>
>> I'm going to commit this since there were no objections.  I do remain
>> concerned about including the __get_clockfreq object code in libc only
>> for PowerPC, but I'm fine with it if others are not concerned.
>
> Could you please expand on your concerns and include an example situation?
>
> Cheers,
> Carlos.

This fragment in sysdeps/unix/sysv/linux/powerpc/Makefile:

+ifeq ($(subdir),misc)
+sysdep_headers += bits/ppc.h
+sysdep_routines += get_clockfreq get_timebase_freq
+tests += test-gettimebasefreq
+endif

Adds get_clockfreq to sysdep_routines which then includes the
get_clockfreq object code into libc.

Normally this object code is only included in librt via:

rt/Makefile:clock-routines := get_clockfreq

So PowerPC will be the only architecture where this is built into in
libc.  This really isn't much of an issue, especially since it's just
a read from the vDSO.

Ryan