perf_counter: re-arrange the perf_event_type

Breaks ABI yet again :-)

Change the event type so that [0, 2^31-1] are regular event types, but
[2^31, 2^32-1] forms a bitmask for overflow events.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171024.047961770@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 037a811..edf5bfb 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -210,13 +210,15 @@
 };
 
 enum perf_event_type {
-	PERF_EVENT_IP		= 0,
+
 	PERF_EVENT_GROUP	= 1,
 
 	PERF_EVENT_MMAP		= 2,
 	PERF_EVENT_MUNMAP	= 3,
 
-	__PERF_EVENT_TID	= 0x100,
+	PERF_EVENT_OVERFLOW	= 1UL << 31,
+	__PERF_EVENT_IP		= 1UL << 30,
+	__PERF_EVENT_TID	= 1UL << 29,
 };
 
 #ifdef __KERNEL__