1 files changed, 81 insertions, 0 deletions
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
new file mode 100644
index 000000000000..312144897970
--- /dev/null
+++ b/kernel/trace/trace_functions.c
@@ -0,0 +1,81 @@
+/*
+ * ring buffer based function tracer
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Based on code from the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 William Lee Irwin III
+ */
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/fs.h>
+
+#include "trace.h"
+
+static void function_reset(struct trace_array *tr)
+{
+	int cpu;
+
+	tr->time_start = ftrace_now(tr->cpu);
+
+	for_each_online_cpu(cpu)
+		tracing_reset(tr->data[cpu]);
+}
+
+static void start_function_trace(struct trace_array *tr)
+{
+	tr->cpu = get_cpu();
+	function_reset(tr);
+	put_cpu();
+
+	tracing_start_cmdline_record();
+	tracing_start_function_trace();
+}
+
+static void stop_function_trace(struct trace_array *tr)
+{
+	tracing_stop_function_trace();
+	tracing_stop_cmdline_record();
+}
+
+static void function_trace_init(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		start_function_trace(tr);
+}
+
+static void function_trace_reset(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		stop_function_trace(tr);
+}
+
+static void function_trace_ctrl_update(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		start_function_trace(tr);
+	else
+		stop_function_trace(tr);
+}
+
+static struct tracer function_trace __read_mostly =
+{
+	.name	     = "ftrace",
+	.init	     = function_trace_init,
+	.reset	     = function_trace_reset,
+	.ctrl_update = function_trace_ctrl_update,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_function,
+#endif
+};
+
+static __init int init_function_trace(void)
+{
+	return register_tracer(&function_trace);
+}
+
+device_initcall(init_function_trace);