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  * Modified by Aravind Menon for Xen
  10  * These modifications are:
  11  * Copyright (C) 2005 Hewlett-Packard Co.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/oprofile.h>
  18 #include <linux/moduleparam.h>
  19 #include <asm/semaphore.h>
  20
  21 #include "oprof.h"
  22 #include "event_buffer.h"
  23 #include "cpu_buffer.h"
  24 #include "buffer_sync.h"
  25 #include "oprofile_stats.h"
  26
  27 struct oprofile_operations oprofile_ops;
  28
  29 unsigned long oprofile_started;
  30 unsigned long backtrace_depth;
  31 static unsigned long is_setup;
  32 static DECLARE_MUTEX(start_sem);
  33
  34 /* timer
  35    0 - use performance monitoring hardware if available
  36    1 - use the timer int mechanism regardless
  37  */
  38 static int timer = 0;
  39
  40 #ifdef CONFIG_XEN
  41 int oprofile_set_active(int active_domains[], unsigned int adomains)
  42 {
  43         int err;
  44
  45         if (!oprofile_ops.set_active)
  46                 return -EINVAL;
  47
  48         down(&start_sem);
  49         err = oprofile_ops.set_active(active_domains, adomains);
  50         up(&start_sem);
  51         return err;
  52 }
  53
  54 int oprofile_set_passive(int passive_domains[], unsigned int pdomains)
  55 {
  56         int err;
  57
  58         if (!oprofile_ops.set_passive)
  59                 return -EINVAL;
  60
  61         down(&start_sem);
  62         err = oprofile_ops.set_passive(passive_domains, pdomains);
  63         up(&start_sem);
  64         return err;
  65 }
  66 #endif
  67
  68 int oprofile_setup(void)
  69 {
  70         int err;
  71
  72         down(&start_sem);
  73
  74         if ((err = alloc_cpu_buffers()))
  75                 goto out;
  76
  77         if ((err = alloc_event_buffer()))
  78                 goto out1;
  79
  80         if (oprofile_ops.setup && (err = oprofile_ops.setup()))
  81                 goto out2;
  82
  83         /* Note even though this starts part of the
  84          * profiling overhead, it's necessary to prevent
  85          * us missing task deaths and eventually oopsing
  86          * when trying to process the event buffer.
  87          */
  88         if ((err = sync_start()))
  89                 goto out3;
  90
  91         is_setup = 1;
  92         up(&start_sem);
  93         return 0;
  94
  95 out3:
  96         if (oprofile_ops.shutdown)
  97                 oprofile_ops.shutdown();
  98 out2:
  99         free_event_buffer();
 100 out1:
 101         free_cpu_buffers();
 102 out:
 103         up(&start_sem);
 104         return err;
 105 }
 106
 107
 108 /* Actually start profiling (echo 1>/dev/oprofile/enable) */
 109 int oprofile_start(void)
 110 {
 111         int err = -EINVAL;
 112
 113         down(&start_sem);
 114
 115         if (!is_setup)
 116                 goto out;
 117
 118         err = 0;
 119
 120         if (oprofile_started)
 121                 goto out;
 122
 123         oprofile_reset_stats();
 124
 125         if ((err = oprofile_ops.start()))
 126                 goto out;
 127
 128         oprofile_started = 1;
 129 out:
 130         up(&start_sem);
 131         return err;
 132 }
 133
 134
 135 /* echo 0>/dev/oprofile/enable */
 136 void oprofile_stop(void)
 137 {
 138         down(&start_sem);
 139         if (!oprofile_started)
 140                 goto out;
 141         oprofile_ops.stop();
 142         oprofile_started = 0;
 143         /* wake up the daemon to read what remains */
 144         wake_up_buffer_waiter();
 145 out:
 146         up(&start_sem);
 147 }
 148
 149
 150 void oprofile_shutdown(void)
 151 {
 152         down(&start_sem);
 153         sync_stop();
 154         if (oprofile_ops.shutdown)
 155                 oprofile_ops.shutdown();
 156         is_setup = 0;
 157         free_event_buffer();
 158         free_cpu_buffers();
 159         up(&start_sem);
 160 }
 161
 162
 163 int oprofile_set_backtrace(unsigned long val)
 164 {
 165         int err = 0;
 166
 167         down(&start_sem);
 168
 169         if (oprofile_started) {
 170                 err = -EBUSY;
 171                 goto out;
 172         }
 173
 174         if (!oprofile_ops.backtrace) {
 175                 err = -EINVAL;
 176                 goto out;
 177         }
 178
 179         backtrace_depth = val;
 180
 181 out:
 182         up(&start_sem);
 183         return err;
 184 }
 185
 186 static int __init oprofile_init(void)
 187 {
 188         int err;
 189
 190         err = oprofile_arch_init(&oprofile_ops);
 191
 192         if (err < 0 || timer) {
 193                 printk(KERN_INFO "oprofile: using timer interrupt.\n");
 194                 oprofile_timer_init(&oprofile_ops);
 195         }
 196
 197         err = oprofilefs_register();
 198         if (err)
 199                 oprofile_arch_exit();
 200
 201         return err;
 202 }
 203
 204
 205 static void __exit oprofile_exit(void)
 206 {
 207         oprofilefs_unregister();
 208         oprofile_arch_exit();
 209 }
 210
 211
 212 module_init(oprofile_init);
 213 module_exit(oprofile_exit);
 214
 215 module_param_named(timer, timer, int, 0644);
 216 MODULE_PARM_DESC(timer, "force use of timer interrupt");
 217
 218 MODULE_LICENSE("GPL");
 219 MODULE_AUTHOR("John Levon <levon@movementarian.org>");
 220 MODULE_DESCRIPTION("OProfile system profiler");