powerpc/perf: Export Power8 generic and cache events to sysfs

Power8 supports a large number of events in each susbystem so when a
user runs:

	perf stat -e branch-instructions sleep 1
	perf stat -e L1-dcache-loads sleep 1

it is not clear as to which PMU events were monitored.

Export the generic hardware and cache perf events for Power8 to sysfs,
so users can precisely determine the PMU event monitored by the generic
event.

Eg:
	cat /sys/bus/event_source/devices/cpu/events/branch-instructions
	event=0x10068

	$ cat /sys/bus/event_source/devices/cpu/events/L1-dcache-loads
	event=0x100ee

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h
index 0691087..e157489 100644
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -136,6 +136,11 @@
  * event 'cpu-cycles' can have two entries in sysfs: 'cpu-cycles' and
  * 'PM_CYC' where the latter is the name by which the event is known in
  * POWER CPU specification.
+ *
+ * Similarly, some hardware and cache events use the same event code. Eg.
+ * on POWER8, both "cache-references" and "L1-dcache-loads" events refer
+ * to the same event, PM_LD_REF_L1.  The suffix, allows us to have two
+ * sysfs objects for the same event and thus two entries/aliases in sysfs.
  */
 #define	EVENT_VAR(_id, _suffix)		event_attr_##_id##_suffix
 #define	EVENT_PTR(_id, _suffix)		&EVENT_VAR(_id, _suffix).attr.attr
@@ -147,5 +152,8 @@
 #define	GENERIC_EVENT_ATTR(_name, _id)	EVENT_ATTR(_name, _id, _g)
 #define	GENERIC_EVENT_PTR(_id)		EVENT_PTR(_id, _g)
 
+#define	CACHE_EVENT_ATTR(_name, _id)	EVENT_ATTR(_name, _id, _c)
+#define	CACHE_EVENT_PTR(_id)		EVENT_PTR(_id, _c)
+
 #define	POWER_EVENT_ATTR(_name, _id)	EVENT_ATTR(_name, _id, _p)
 #define	POWER_EVENT_PTR(_id)		EVENT_PTR(_id, _p)