kernel/trace/trace_functions.c

   1 /*
   2  * ring buffer based function tracer
   3  *
   4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
   6  *
   7  * Based on code from the latency_tracer, that is:
   8  *
   9  *  Copyright (C) 2004-2006 Ingo Molnar
  10  *  Copyright (C) 2004 William Lee Irwin III
  11  */
  12 #include <linux/debugfs.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/ftrace.h>
  15 #include <linux/fs.h>
  16
  17 #include "trace.h"
  18
  19 static void start_function_trace(struct trace_array *tr)
  20 {
  21         tr->cpu = get_cpu();
  22         tracing_reset_online_cpus(tr);
  23         put_cpu();
  24
  25         tracing_start_cmdline_record();
  26         tracing_start_function_trace();
  27 }
  28
  29 static void stop_function_trace(struct trace_array *tr)
  30 {
  31         tracing_stop_function_trace();
  32         tracing_stop_cmdline_record();
  33 }
  34
  35 static int function_trace_init(struct trace_array *tr)
  36 {
  37         start_function_trace(tr);
  38         return 0;
  39 }
  40
  41 static void function_trace_reset(struct trace_array *tr)
  42 {
  43         stop_function_trace(tr);
  44 }
  45
  46 static void function_trace_start(struct trace_array *tr)
  47 {
  48         tracing_reset_online_cpus(tr);
  49 }
  50
  51 static struct tracer function_trace __read_mostly =
  52 {
  53         .name        = "function",
  54         .init        = function_trace_init,
  55         .reset       = function_trace_reset,
  56         .start       = function_trace_start,
  57 #ifdef CONFIG_FTRACE_SELFTEST
  58         .selftest    = trace_selftest_startup_function,
  59 #endif
  60 };
  61
  62 static __init int init_function_trace(void)
  63 {
  64         return register_tracer(&function_trace);
  65 }
  66
  67 device_initcall(init_function_trace);