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   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 <linux/workqueue.h>
  16 #include <linux/time.h>
  17 #include <asm/mutex.h>
  18
  19 #include "oprof.h"
  20 #include "event_buffer.h"
  21 #include "cpu_buffer.h"
  22 #include "buffer_sync.h"
  23 #include "oprofile_stats.h"
  24
  25 struct oprofile_operations oprofile_ops;
  26
  27 unsigned long oprofile_started;
  28 unsigned long oprofile_backtrace_depth;
  29 static unsigned long is_setup;
  30 static DEFINE_MUTEX(start_mutex);
  31
  32 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
  33
  34 static void switch_worker(struct work_struct *work);
  35 static DECLARE_DELAYED_WORK(switch_work, switch_worker);
  36 #define TIME_SLICE_DEFAULT              1
  37
  38 #endif
  39
  40 /* timer
  41    0 - use performance monitoring hardware if available
  42    1 - use the timer int mechanism regardless
  43  */
  44 static int timer = 0;
  45
  46 int oprofile_setup(void)
  47 {
  48         int err;
  49
  50         mutex_lock(&start_mutex);
  51
  52         if ((err = alloc_cpu_buffers()))
  53                 goto out;
  54
  55         if ((err = alloc_event_buffer()))
  56                 goto out1;
  57
  58         if (oprofile_ops.setup && (err = oprofile_ops.setup()))
  59                 goto out2;
  60
  61         /* Note even though this starts part of the
  62          * profiling overhead, it's necessary to prevent
  63          * us missing task deaths and eventually oopsing
  64          * when trying to process the event buffer.
  65          */
  66         if (oprofile_ops.sync_start) {
  67                 int sync_ret = oprofile_ops.sync_start();
  68                 switch (sync_ret) {
  69                 case 0:
  70                         goto post_sync;
  71                 case 1:
  72                         goto do_generic;
  73                 case -1:
  74                         goto out3;
  75                 default:
  76                         goto out3;
  77                 }
  78         }
  79 do_generic:
  80         if ((err = sync_start()))
  81                 goto out3;
  82
  83 post_sync:
  84         is_setup = 1;
  85         mutex_unlock(&start_mutex);
  86         return 0;
  87
  88 out3:
  89         if (oprofile_ops.shutdown)
  90                 oprofile_ops.shutdown();
  91 out2:
  92         free_event_buffer();
  93 out1:
  94         free_cpu_buffers();
  95 out:
  96         mutex_unlock(&start_mutex);
  97         return err;
  98 }
  99
 100 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
 101
 102 static void start_switch_worker(void)
 103 {
 104         schedule_delayed_work(&switch_work, oprofile_time_slice);
 105 }
 106
 107 static void switch_worker(struct work_struct *work)
 108 {
 109         if (!oprofile_ops.switch_events())
 110                 start_switch_worker();
 111 }
 112
 113 #endif
 114
 115 /* Actually start profiling (echo 1>/dev/oprofile/enable) */
 116 int oprofile_start(void)
 117 {
 118         int err = -EINVAL;
 119
 120         mutex_lock(&start_mutex);
 121
 122         if (!is_setup)
 123                 goto out;
 124
 125         err = 0;
 126
 127         if (oprofile_started)
 128                 goto out;
 129
 130         oprofile_reset_stats();
 131
 132         if ((err = oprofile_ops.start()))
 133                 goto out;
 134
 135 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
 136         if (oprofile_ops.switch_events)
 137                 start_switch_worker();
 138 #endif
 139
 140         oprofile_started = 1;
 141 out:
 142         mutex_unlock(&start_mutex);
 143         return err;
 144 }
 145
 146
 147 /* echo 0>/dev/oprofile/enable */
 148 void oprofile_stop(void)
 149 {
 150         mutex_lock(&start_mutex);
 151         if (!oprofile_started)
 152                 goto out;
 153         oprofile_ops.stop();
 154         oprofile_started = 0;
 155
 156 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
 157         cancel_delayed_work_sync(&switch_work);
 158 #endif
 159
 160         /* wake up the daemon to read what remains */
 161         wake_up_buffer_waiter();
 162 out:
 163         mutex_unlock(&start_mutex);
 164 }
 165
 166
 167 void oprofile_shutdown(void)
 168 {
 169         mutex_lock(&start_mutex);
 170         if (oprofile_ops.sync_stop) {
 171                 int sync_ret = oprofile_ops.sync_stop();
 172                 switch (sync_ret) {
 173                 case 0:
 174                         goto post_sync;
 175                 case 1:
 176                         goto do_generic;
 177                 default:
 178                         goto post_sync;
 179                 }
 180         }
 181 do_generic:
 182         sync_stop();
 183 post_sync:
 184         if (oprofile_ops.shutdown)
 185                 oprofile_ops.shutdown();
 186         is_setup = 0;
 187         free_event_buffer();
 188         free_cpu_buffers();
 189         mutex_unlock(&start_mutex);
 190 }
 191
 192 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
 193
 194 /* User inputs in ms, converts to jiffies */
 195 int oprofile_set_timeout(unsigned long val_msec)
 196 {
 197         int err = 0;
 198         unsigned long time_slice;
 199
 200         mutex_lock(&start_mutex);
 201
 202         if (oprofile_started) {
 203                 err = -EBUSY;
 204                 goto out;
 205         }
 206
 207         if (!oprofile_ops.switch_events) {
 208                 err = -EINVAL;
 209                 goto out;
 210         }
 211
 212         time_slice = msecs_to_jiffies(val_msec);
 213         if (time_slice == MAX_JIFFY_OFFSET) {
 214                 err = -EINVAL;
 215                 goto out;
 216         }
 217
 218         oprofile_time_slice = time_slice;
 219
 220 out:
 221         mutex_unlock(&start_mutex);
 222         return err;
 223
 224 }
 225
 226 #endif
 227
 228 int oprofile_set_backtrace(unsigned long val)
 229 {
 230         int err = 0;
 231
 232         mutex_lock(&start_mutex);
 233
 234         if (oprofile_started) {
 235                 err = -EBUSY;
 236                 goto out;
 237         }
 238
 239         if (!oprofile_ops.backtrace) {
 240                 err = -EINVAL;
 241                 goto out;
 242         }
 243
 244         oprofile_backtrace_depth = val;
 245
 246 out:
 247         mutex_unlock(&start_mutex);
 248         return err;
 249 }
 250
 251 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
 252
 253 static void __init oprofile_multiplexing_init(void)
 254 {
 255         oprofile_time_slice = msecs_to_jiffies(TIME_SLICE_DEFAULT);
 256 }
 257
 258 #endif
 259
 260 static int __init oprofile_init(void)
 261 {
 262         int err;
 263
 264 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
 265         oprofile_multiplexing_init();
 266 #endif
 267
 268         err = oprofile_arch_init(&oprofile_ops);
 269
 270         if (err < 0 || timer) {
 271                 printk(KERN_INFO "oprofile: using timer interrupt.\n");
 272                 oprofile_timer_init(&oprofile_ops);
 273         }
 274
 275         err = oprofilefs_register();
 276         if (err)
 277                 oprofile_arch_exit();
 278
 279         return err;
 280 }
 281
 282
 283 static void __exit oprofile_exit(void)
 284 {
 285         oprofilefs_unregister();
 286         oprofile_arch_exit();
 287 }
 288
 289
 290 module_init(oprofile_init);
 291 module_exit(oprofile_exit);
 292
 293 module_param_named(timer, timer, int, 0644);
 294 MODULE_PARM_DESC(timer, "force use of timer interrupt");
 295
 296 MODULE_LICENSE("GPL");
 297 MODULE_AUTHOR("John Levon <levon@movementarian.org>");
 298 MODULE_DESCRIPTION("OProfile system profiler");