perf_counter: software counter event infrastructure

Provide generic software counter infrastructure that supports
software events.

This will be used to allow sample based profiling based on software
events such as pagefaults. The current infrastructure can only
provide a count of such events, no place information.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@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 dde5645..3fefc3b8 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -126,6 +126,7 @@
 	unsigned long			counter_base;
 	int				nmi;
 	unsigned int			idx;
+	atomic64_t			count; /* software */
 	atomic64_t			prev_count;
 	u64				irq_period;
 	atomic64_t			period_left;
@@ -283,6 +284,8 @@
 	return !counter->hw_event.raw && counter->hw_event.type < 0;
 }
 
+extern void perf_swcounter_event(enum hw_event_types, u64, int, struct pt_regs *);
+
 #else
 static inline void
 perf_counter_task_sched_in(struct task_struct *task, int cpu)		{ }
@@ -295,10 +298,13 @@
 static inline void perf_counter_notify(struct pt_regs *regs)		{ }
 static inline void perf_counter_print_debug(void)			{ }
 static inline void perf_counter_unthrottle(void)			{ }
-static inline void hw_perf_restore(u64 ctrl)			{ }
+static inline void hw_perf_restore(u64 ctrl)				{ }
 static inline u64 hw_perf_save_disable(void)		      { return 0; }
 static inline int perf_counter_task_disable(void)	{ return -EINVAL; }
 static inline int perf_counter_task_enable(void)	{ return -EINVAL; }
+
+static inline void perf_swcounter_event(enum hw_event_types event, u64 nr,
+					int nmi, struct pt_regs *regs)	{ }
 #endif
 
 #endif /* __KERNEL__ */