Linux-2.6.12-rc2
[linux-2.6.git] / drivers / oprofile / oprof.c
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/semaphore.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 DECLARE_MUTEX(start_sem);
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         down(&start_sem);
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         up(&start_sem);
61         return 0;
62  
63 out3:
64         if (oprofile_ops.shutdown)
65                 oprofile_ops.shutdown();
66 out2:
67         free_event_buffer();
68 out1:
69         free_cpu_buffers();
70 out:
71         up(&start_sem);
72         return err;
73 }
74
75
76 /* Actually start profiling (echo 1>/dev/oprofile/enable) */
77 int oprofile_start(void)
78 {
79         int err = -EINVAL;
80  
81         down(&start_sem);
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;
97 out:
98         up(&start_sem); 
99         return err;
100 }
101
102  
103 /* echo 0>/dev/oprofile/enable */
104 void oprofile_stop(void)
105 {
106         down(&start_sem);
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();
113 out:
114         up(&start_sem);
115 }
116
117
118 void oprofile_shutdown(void)
119 {
120         down(&start_sem);
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         up(&start_sem);
128 }
129
130
131 int oprofile_set_backtrace(unsigned long val)
132 {
133         int err = 0;
134
135         down(&start_sem);
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
149 out:
150         up(&start_sem);
151         return err;
152 }
153
154 static 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
173 static void __exit oprofile_exit(void)
174 {
175         oprofilefs_unregister();
176         oprofile_arch_exit();
177 }
178
179  
180 module_init(oprofile_init);
181 module_exit(oprofile_exit);
182
183 module_param_named(timer, timer, int, 0644);
184 MODULE_PARM_DESC(timer, "force use of timer interrupt");
185  
186 MODULE_LICENSE("GPL");
187 MODULE_AUTHOR("John Levon <levon@movementarian.org>");
188 MODULE_DESCRIPTION("OProfile system profiler");