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1da177e4 LT |
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> | |
59cc185a | 15 | #include <asm/mutex.h> |
1da177e4 LT |
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; | |
59cc185a | 28 | static DEFINE_MUTEX(start_mutex); |
1da177e4 LT |
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 | ||
59cc185a | 40 | mutex_lock(&start_mutex); |
1da177e4 LT |
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; | |
59cc185a | 60 | mutex_unlock(&start_mutex); |
1da177e4 LT |
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: | |
59cc185a | 71 | mutex_unlock(&start_mutex); |
1da177e4 LT |
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 | ||
59cc185a | 81 | mutex_lock(&start_mutex); |
1da177e4 LT |
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: | |
59cc185a | 98 | mutex_unlock(&start_mutex); |
1da177e4 LT |
99 | return err; |
100 | } | |
101 | ||
102 | ||
103 | /* echo 0>/dev/oprofile/enable */ | |
104 | void oprofile_stop(void) | |
105 | { | |
59cc185a | 106 | mutex_lock(&start_mutex); |
1da177e4 LT |
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: | |
59cc185a | 114 | mutex_unlock(&start_mutex); |
1da177e4 LT |
115 | } |
116 | ||
117 | ||
118 | void oprofile_shutdown(void) | |
119 | { | |
59cc185a | 120 | mutex_lock(&start_mutex); |
1da177e4 LT |
121 | sync_stop(); |
122 | if (oprofile_ops.shutdown) | |
123 | oprofile_ops.shutdown(); | |
124 | is_setup = 0; | |
125 | free_event_buffer(); | |
126 | free_cpu_buffers(); | |
59cc185a | 127 | mutex_unlock(&start_mutex); |
1da177e4 LT |
128 | } |
129 | ||
130 | ||
131 | int oprofile_set_backtrace(unsigned long val) | |
132 | { | |
133 | int err = 0; | |
134 | ||
59cc185a | 135 | mutex_lock(&start_mutex); |
1da177e4 LT |
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: | |
59cc185a | 150 | mutex_unlock(&start_mutex); |
1da177e4 LT |
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"); |