ftrace: event profile hooks

Impact: new tracing infrastructure feature

Provide infrastructure to generate software perf counter events
from tracepoints.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090319194233.557364871@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
new file mode 100644
index 0000000..22cba99
--- /dev/null
+++ b/kernel/trace/trace_event_profile.c
@@ -0,0 +1,31 @@
+/*
+ * trace event based perf counter profiling
+ *
+ * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com>
+ *
+ */
+
+#include "trace.h"
+
+int ftrace_profile_enable(int event_id)
+{
+	struct ftrace_event_call *event;
+
+	for_each_event(event) {
+		if (event->id == event_id)
+			return event->profile_enable(event);
+	}
+
+	return -EINVAL;
+}
+
+void ftrace_profile_disable(int event_id)
+{
+	struct ftrace_event_call *event;
+
+	for_each_event(event) {
+		if (event->id == event_id)
+			return event->profile_disable(event);
+	}
+}
+