Adding cache shape info to powerpc

[Benjamin Herrenschmidt]

On Thu, 2016-12-01 at 09:10 -0600, Steven Munroe wrote:
> > The old format was only used by other architectures, not powerpc, do I
> > still need to pick different numbers in that case ?
> > 
> > As for IFUNC I don't think so but I'll let Steve reply as I believe he
> > is the original requestor for the functionality.
> > 
> 
> Ben were are we on this? 
> 
> This is needed to fix a customer reported bug for lack of
> sysconf(_SC_*CACHE_SIZE) support on powerpc.
> 
> Adding this information to the cputable and then auxv fits into the
> current sysconf infrastructure best.
> 
> When we know the AT_ info format and upstream Kernel version we can
> update kernel-features.h and enable a sysconf.c fragment to return these
> values for powerpc 

I was waiting for a review by you guys to tell me what you want in the
AT_* entries. People weren't too happy with my first sketch that used
the same entries used by a couple of other archs but with a slightly
different format.

Once we agree on an encoding/format I can resend the patches.

Cheers,
Ben.