2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Based on code from the latency_tracer, that is:
9 * Copyright (C) 2004-2006 Ingo Molnar
10 * Copyright (C) 2004 William Lee Irwin III
12 #include <linux/debugfs.h>
13 #include <linux/uaccess.h>
14 #include <linux/ftrace.h>
19 static struct trace_array *func_trace;
21 static void start_function_trace(struct trace_array *tr)
24 tracing_reset_online_cpus(tr);
27 tracing_start_cmdline_record();
28 tracing_start_function_trace();
31 static void stop_function_trace(struct trace_array *tr)
33 tracing_stop_function_trace();
34 tracing_stop_cmdline_record();
37 static int function_trace_init(struct trace_array *tr)
40 start_function_trace(tr);
44 static void function_trace_reset(struct trace_array *tr)
46 stop_function_trace(tr);
49 static void function_trace_start(struct trace_array *tr)
51 tracing_reset_online_cpus(tr);
55 function_stack_trace_call(unsigned long ip, unsigned long parent_ip)
57 struct trace_array *tr = func_trace;
58 struct trace_array_cpu *data;
64 if (unlikely(!ftrace_function_enabled))
68 * Need to use raw, since this must be called before the
69 * recursive protection is performed.
71 local_irq_save(flags);
72 cpu = raw_smp_processor_id();
74 disabled = atomic_inc_return(&data->disabled);
76 if (likely(disabled == 1)) {
80 * __ftrace_trace_stack,
82 * function_stack_trace_call
86 __trace_stack(tr, data, flags, 5, pc);
89 atomic_dec(&data->disabled);
90 local_irq_restore(flags);
93 static struct ftrace_ops trace_stack_ops __read_mostly =
95 .func = function_stack_trace_call,
100 TRACE_FUNC_OPT_STACK = 0x1,
103 static struct tracer_opt func_opts[] = {
104 #ifdef CONFIG_STACKTRACE
105 { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
107 { } /* Always set a last empty entry */
110 static struct tracer_flags func_flags = {
111 .val = 0, /* By default: all flags disabled */
115 static int func_set_flag(u32 old_flags, u32 bit, int set)
117 if (bit == TRACE_FUNC_OPT_STACK) {
118 /* do nothing if already set */
119 if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
123 register_ftrace_function(&trace_stack_ops);
125 unregister_ftrace_function(&trace_stack_ops);
133 static struct tracer function_trace __read_mostly =
136 .init = function_trace_init,
137 .reset = function_trace_reset,
138 .start = function_trace_start,
139 .flags = &func_flags,
140 .set_flag = func_set_flag,
141 #ifdef CONFIG_FTRACE_SELFTEST
142 .selftest = trace_selftest_startup_function,
146 static __init int init_function_trace(void)
148 return register_tracer(&function_trace);
151 device_initcall(init_function_trace);