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
23 struct oprofile_operations oprofile_ops;
24
25 unsigned long oprofile_started;
26 unsigned long backtrace_depth;
27 static unsigned long is_setup;
28 static DEFINE_MUTEX(start_mutex);
29
30 /* timer
31 0 - use performance monitoring hardware if available
32 1 - use the timer int mechanism regardless
33 */
34 static int timer = 0;
35
36 int 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 (oprofile_ops.sync_start) {
57 int sync_ret = oprofile_ops.sync_start();
58 switch (sync_ret) {
59 case 0:
60 goto post_sync;
61 case 1:
62 goto do_generic;
63 case -1:
64 goto out3;
65 default:
66 goto out3;
67 }
68 }
69 do_generic:
70 if ((err = sync_start()))
71 goto out3;
72
73 post_sync:
74 is_setup = 1;
75 mutex_unlock(&start_mutex);
76 return 0;
77
78 out3:
79 if (oprofile_ops.shutdown)
80 oprofile_ops.shutdown();
81 out2:
82 free_event_buffer();
83 out1:
84 free_cpu_buffers();
85 out:
86 mutex_unlock(&start_mutex);
87 return err;
88 }
89
90
91 /* Actually start profiling (echo 1>/dev/oprofile/enable) */
92 int oprofile_start(void)
93 {
94 int err = -EINVAL;
95
96 mutex_lock(&start_mutex);
97
98 if (!is_setup)
99 goto out;
100
101 err = 0;
102
103 if (oprofile_started)
104 goto out;
105
106 oprofile_reset_stats();
107
108 if ((err = oprofile_ops.start()))
109 goto out;
110
111 oprofile_started = 1;
112 out:
113 mutex_unlock(&start_mutex);
114 return err;
115 }
116
117
118 /* echo 0>/dev/oprofile/enable */
119 void oprofile_stop(void)
120 {
121 mutex_lock(&start_mutex);
122 if (!oprofile_started)
123 goto out;
124 oprofile_ops.stop();
125 oprofile_started = 0;
126 /* wake up the daemon to read what remains */
127 wake_up_buffer_waiter();
128 out:
129 mutex_unlock(&start_mutex);
130 }
131
132
133 void oprofile_shutdown(void)
134 {
135 mutex_lock(&start_mutex);
136 if (oprofile_ops.sync_stop) {
137 int sync_ret = oprofile_ops.sync_stop();
138 switch (sync_ret) {
139 case 0:
140 goto post_sync;
141 case 1:
142 goto do_generic;
143 default:
144 goto post_sync;
145 }
146 }
147 do_generic:
148 sync_stop();
149 post_sync:
150 if (oprofile_ops.shutdown)
151 oprofile_ops.shutdown();
152 is_setup = 0;
153 free_event_buffer();
154 free_cpu_buffers();
155 mutex_unlock(&start_mutex);
156 }
157
158
159 int oprofile_set_backtrace(unsigned long val)
160 {
161 int err = 0;
162
163 mutex_lock(&start_mutex);
164
165 if (oprofile_started) {
166 err = -EBUSY;
167 goto out;
168 }
169
170 if (!oprofile_ops.backtrace) {
171 err = -EINVAL;
172 goto out;
173 }
174
175 backtrace_depth = val;
176
177 out:
178 mutex_unlock(&start_mutex);
179 return err;
180 }
181
182 static int __init oprofile_init(void)
183 {
184 int err;
185
186 err = oprofile_arch_init(&oprofile_ops);
187
188 if (err < 0 || timer) {
189 printk(KERN_INFO "oprofile: using timer interrupt.\n");
190 oprofile_timer_init(&oprofile_ops);
191 }
192
193 err = oprofilefs_register();
194 if (err)
195 oprofile_arch_exit();
196
197 return err;
198 }
199
200
201 static void __exit oprofile_exit(void)
202 {
203 oprofilefs_unregister();
204 oprofile_arch_exit();
205 }
206
207
208 module_init(oprofile_init);
209 module_exit(oprofile_exit);
210
211 module_param_named(timer, timer, int, 0644);
212 MODULE_PARM_DESC(timer, "force use of timer interrupt");
213
214 MODULE_LICENSE("GPL");
215 MODULE_AUTHOR("John Levon <levon@movementarian.org>");
216 MODULE_DESCRIPTION("OProfile system profiler");
217
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