1/**
2 * @file oprof.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author John Levon <levon@movementarian.org>
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/oprofile.h>
14#include <linux/moduleparam.h>
15#include <asm/mutex.h>
16
17#include "oprof.h"
18#include "event_buffer.h"
19#include "cpu_buffer.h"
20#include "buffer_sync.h"
21#include "oprofile_stats.h"
22
23struct oprofile_operations oprofile_ops;
24
25unsigned long oprofile_started;
26unsigned long backtrace_depth;
27static unsigned long is_setup;
28static DEFINE_MUTEX(start_mutex);
29
30/* timer
31   0 - use performance monitoring hardware if available
32   1 - use the timer int mechanism regardless
33 */
34static int timer = 0;
35
36int oprofile_setup(void)
37{
38	int err;
39
40	mutex_lock(&start_mutex);
41
42	if ((err = alloc_cpu_buffers()))
43		goto out;
44
45	if ((err = alloc_event_buffer()))
46		goto out1;
47
48	if (oprofile_ops.setup && (err = oprofile_ops.setup()))
49		goto out2;
50
51	/* Note even though this starts part of the
52	 * profiling overhead, it's necessary to prevent
53	 * us missing task deaths and eventually oopsing
54	 * when trying to process the event buffer.
55	 */
56	if ((err = sync_start()))
57		goto out3;
58
59	is_setup = 1;
60	mutex_unlock(&start_mutex);
61	return 0;
62
63out3:
64	if (oprofile_ops.shutdown)
65		oprofile_ops.shutdown();
66out2:
67	free_event_buffer();
68out1:
69	free_cpu_buffers();
70out:
71	mutex_unlock(&start_mutex);
72	return err;
73}
74
75
76/* Actually start profiling (echo 1>/dev/oprofile/enable) */
77int oprofile_start(void)
78{
79	int err = -EINVAL;
80
81	mutex_lock(&start_mutex);
82
83	if (!is_setup)
84		goto out;
85
86	err = 0;
87
88	if (oprofile_started)
89		goto out;
90
91	oprofile_reset_stats();
92
93	if ((err = oprofile_ops.start()))
94		goto out;
95
96	oprofile_started = 1;
97out:
98	mutex_unlock(&start_mutex);
99	return err;
100}
101
102
103/* echo 0>/dev/oprofile/enable */
104void oprofile_stop(void)
105{
106	mutex_lock(&start_mutex);
107	if (!oprofile_started)
108		goto out;
109	oprofile_ops.stop();
110	oprofile_started = 0;
111	/* wake up the daemon to read what remains */
112	wake_up_buffer_waiter();
113out:
114	mutex_unlock(&start_mutex);
115}
116
117
118void oprofile_shutdown(void)
119{
120	mutex_lock(&start_mutex);
121	sync_stop();
122	if (oprofile_ops.shutdown)
123		oprofile_ops.shutdown();
124	is_setup = 0;
125	free_event_buffer();
126	free_cpu_buffers();
127	mutex_unlock(&start_mutex);
128}
129
130
131int oprofile_set_backtrace(unsigned long val)
132{
133	int err = 0;
134
135	mutex_lock(&start_mutex);
136
137	if (oprofile_started) {
138		err = -EBUSY;
139		goto out;
140	}
141
142	if (!oprofile_ops.backtrace) {
143		err = -EINVAL;
144		goto out;
145	}
146
147	backtrace_depth = val;
148
149out:
150	mutex_unlock(&start_mutex);
151	return err;
152}
153
154static int __init oprofile_init(void)
155{
156	int err;
157
158	err = oprofile_arch_init(&oprofile_ops);
159
160	if (err < 0 || timer) {
161		printk(KERN_INFO "oprofile: using timer interrupt.\n");
162		oprofile_timer_init(&oprofile_ops);
163	}
164
165	err = oprofilefs_register();
166	if (err)
167		oprofile_arch_exit();
168
169	return err;
170}
171
172
173static void __exit oprofile_exit(void)
174{
175	oprofilefs_unregister();
176	oprofile_arch_exit();
177}
178
179
180module_init(oprofile_init);
181module_exit(oprofile_exit);
182
183module_param_named(timer, timer, int, 0644);
184MODULE_PARM_DESC(timer, "force use of timer interrupt");
185
186MODULE_LICENSE("GPL");
187MODULE_AUTHOR("John Levon <levon@movementarian.org>");
188MODULE_DESCRIPTION("OProfile system profiler");
189