tree 5b53e458b7c154dc774897399bef867d4da39e63
parent a67f144739c42f99e2a4cf43e8cf4e1cc75719fd
author Cody P Schafer <cody@linux.vnet.ibm.com> 1394773238 +1100
committer Benjamin Herrenschmidt <benh@kernel.crashing.org> 1395614909 +1100

powerpc/perf: Add 24x7 interface headers

24x7 (also called hv_24x7 or H_24X7) is an interface to obtain
performance counters from the hypervisor. These counters do not have a
fixed format/possition and are instead documented in a "24x7 Catalog",
which is provided by the hypervisor (that interface is also documented
paritialy in the included hv-24x7-catalog.h and fully in at
https://raw.githubusercontent.com/jmesmon/catalog-24x7/master/hv-24x7-catalog.h ).

The 24x7 data access is simply a copy operation into a 4 dimentional
array of 64bit counters (from hypervisor to kernel memory). There is no
interupt triggered on overflow, these are completely disjoint from the
typical power pmu.

This method of obtaining performance counters from the hypervisor is
intended to paritialy replace the gpci interface.

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>