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-rw-r--r--kernel/trace/Kconfig13
-rw-r--r--kernel/trace/Makefile1
-rw-r--r--kernel/trace/trace_functions.c73
3 files changed, 87 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index ce70677afbf..1399f372b5d 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -8,3 +8,16 @@ config TRACING
bool
select DEBUG_FS
+config FTRACE
+ bool "Kernel Function Tracer"
+ depends on DEBUG_KERNEL && HAVE_FTRACE
+ select FRAME_POINTER
+ select TRACING
+ help
+ Enable the kernel to trace every kernel function. This is done
+ by using a compiler feature to insert a small, 5-byte No-Operation
+ instruction to the beginning of every kernel function, which NOP
+ sequence is then dynamically patched into a tracer call when
+ tracing is enabled by the administrator. If it's runtime disabled
+ (the bootup default), then the overhead of the instructions is very
+ small and not measurable even in micro-benchmarks.
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 7af40317525..6bb5e50b4a4 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_FTRACE) += libftrace.o
obj-$(CONFIG_TRACING) += trace.o
+obj-$(CONFIG_FTRACE) += trace_functions.o
libftrace-y := ftrace.o
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
new file mode 100644
index 00000000000..82988c5336e
--- /dev/null
+++ b/kernel/trace/trace_functions.c
@@ -0,0 +1,73 @@
+/*
+ * 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/fs.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static notrace void function_reset(struct trace_array *tr)
+{
+ int cpu;
+
+ tr->time_start = now(tr->cpu);
+
+ for_each_online_cpu(cpu)
+ tracing_reset(tr->data[cpu]);
+}
+
+static notrace void start_function_trace(struct trace_array *tr)
+{
+ function_reset(tr);
+ tracing_start_function_trace();
+}
+
+static notrace void stop_function_trace(struct trace_array *tr)
+{
+ tracing_stop_function_trace();
+}
+
+static notrace void function_trace_init(struct trace_array *tr)
+{
+ if (tr->ctrl)
+ start_function_trace(tr);
+}
+
+static notrace void function_trace_reset(struct trace_array *tr)
+{
+ if (tr->ctrl)
+ stop_function_trace(tr);
+}
+
+static notrace 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,
+};
+
+static __init int init_function_trace(void)
+{
+ return register_tracer(&function_trace);
+}
+
+device_initcall(init_function_trace);