perf_counter, x86: Add mmap counter read support
Update the mmap control page with the needed information to
use the userspace RDPMC instruction for self monitoring.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/include/asm/perf_counter.h b/arch/x86/include/asm/perf_counter.h
index 5fb33e1..fa64e40 100644
--- a/arch/x86/include/asm/perf_counter.h
+++ b/arch/x86/include/asm/perf_counter.h
@@ -87,6 +87,9 @@
#ifdef CONFIG_PERF_COUNTERS
extern void init_hw_perf_counters(void);
extern void perf_counters_lapic_init(void);
+
+#define PERF_COUNTER_INDEX_OFFSET 0
+
#else
static inline void init_hw_perf_counters(void) { }
static inline void perf_counters_lapic_init(void) { }
