kernel/rtmutex-tester.c

   1 /*
   2  * RT-Mutex-tester: scriptable tester for rt mutexes
   3  *
   4  * started by Thomas Gleixner:
   5  *
   6  *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
   7  *
   8  */
   9 #include <linux/kthread.h>
  10 #include <linux/module.h>
  11 #include <linux/sched.h>
  12 #include <linux/smp_lock.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/sysdev.h>
  15 #include <linux/timer.h>
  16
  17 #include "rtmutex.h"
  18
  19 #define MAX_RT_TEST_THREADS     8
  20 #define MAX_RT_TEST_MUTEXES     8
  21
  22 static spinlock_t rttest_lock;
  23 static atomic_t rttest_event;
  24
  25 struct test_thread_data {
  26         int                     opcode;
  27         int                     opdata;
  28         int                     mutexes[MAX_RT_TEST_MUTEXES];
  29         int                     bkl;
  30         int                     event;
  31         struct sys_device       sysdev;
  32 };
  33
  34 static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
  35 static struct task_struct *threads[MAX_RT_TEST_THREADS];
  36 static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];
  37
  38 enum test_opcodes {
  39         RTTEST_NOP = 0,
  40         RTTEST_SCHEDOT,         /* 1 Sched other, data = nice */
  41         RTTEST_SCHEDRT,         /* 2 Sched fifo, data = prio */
  42         RTTEST_LOCK,            /* 3 Lock uninterruptible, data = lockindex */
  43         RTTEST_LOCKNOWAIT,      /* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
  44         RTTEST_LOCKINT,         /* 5 Lock interruptible, data = lockindex */
  45         RTTEST_LOCKINTNOWAIT,   /* 6 Lock interruptible no wait in wakeup, data = lockindex */
  46         RTTEST_LOCKCONT,        /* 7 Continue locking after the wakeup delay */
  47         RTTEST_UNLOCK,          /* 8 Unlock, data = lockindex */
  48         RTTEST_LOCKBKL,         /* 9 Lock BKL */
  49         RTTEST_UNLOCKBKL,       /* 10 Unlock BKL */
  50         RTTEST_SIGNAL,          /* 11 Signal other test thread, data = thread id */
  51         RTTEST_RESETEVENT = 98, /* 98 Reset event counter */
  52         RTTEST_RESET = 99,      /* 99 Reset all pending operations */
  53 };
  54
  55 static int handle_op(struct test_thread_data *td, int lockwakeup)
  56 {
  57         int i, id, ret = -EINVAL;
  58
  59         switch(td->opcode) {
  60
  61         case RTTEST_NOP:
  62                 return 0;
  63
  64         case RTTEST_LOCKCONT:
  65                 td->mutexes[td->opdata] = 1;
  66                 td->event = atomic_add_return(1, &rttest_event);
  67                 return 0;
  68
  69         case RTTEST_RESET:
  70                 for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
  71                         if (td->mutexes[i] == 4) {
  72                                 rt_mutex_unlock(&mutexes[i]);
  73                                 td->mutexes[i] = 0;
  74                         }
  75                 }
  76
  77                 if (!lockwakeup && td->bkl == 4) {
  78                         unlock_kernel();
  79                         td->bkl = 0;
  80                 }
  81                 return 0;
  82
  83         case RTTEST_RESETEVENT:
  84                 atomic_set(&rttest_event, 0);
  85                 return 0;
  86
  87         default:
  88                 if (lockwakeup)
  89                         return ret;
  90         }
  91
  92         switch(td->opcode) {
  93
  94         case RTTEST_LOCK:
  95         case RTTEST_LOCKNOWAIT:
  96                 id = td->opdata;
  97                 if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
  98                         return ret;
  99
 100                 td->mutexes[id] = 1;
 101                 td->event = atomic_add_return(1, &rttest_event);
 102                 rt_mutex_lock(&mutexes[id]);
 103                 td->event = atomic_add_return(1, &rttest_event);
 104                 td->mutexes[id] = 4;
 105                 return 0;
 106
 107         case RTTEST_LOCKINT:
 108         case RTTEST_LOCKINTNOWAIT:
 109                 id = td->opdata;
 110                 if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
 111                         return ret;
 112
 113                 td->mutexes[id] = 1;
 114                 td->event = atomic_add_return(1, &rttest_event);
 115                 ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
 116                 td->event = atomic_add_return(1, &rttest_event);
 117                 td->mutexes[id] = ret ? 0 : 4;
 118                 return ret ? -EINTR : 0;
 119
 120         case RTTEST_UNLOCK:
 121                 id = td->opdata;
 122                 if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
 123                         return ret;
 124
 125                 td->event = atomic_add_return(1, &rttest_event);
 126                 rt_mutex_unlock(&mutexes[id]);
 127                 td->event = atomic_add_return(1, &rttest_event);
 128                 td->mutexes[id] = 0;
 129                 return 0;
 130
 131         case RTTEST_LOCKBKL:
 132                 if (td->bkl)
 133                         return 0;
 134                 td->bkl = 1;
 135                 lock_kernel();
 136                 td->bkl = 4;
 137                 return 0;
 138
 139         case RTTEST_UNLOCKBKL:
 140                 if (td->bkl != 4)
 141                         break;
 142                 unlock_kernel();
 143                 td->bkl = 0;
 144                 return 0;
 145
 146         default:
 147                 break;
 148         }
 149         return ret;
 150 }
 151
 152 /*
 153  * Schedule replacement for rtsem_down(). Only called for threads with
 154  * PF_MUTEX_TESTER set.
 155  *
 156  * This allows us to have finegrained control over the event flow.
 157  *
 158  */
 159 void schedule_rt_mutex_test(struct rt_mutex *mutex)
 160 {
 161         int tid, op, dat;
 162         struct test_thread_data *td;
 163
 164         /* We have to lookup the task */
 165         for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
 166                 if (threads[tid] == current)
 167                         break;
 168         }
 169
 170         BUG_ON(tid == MAX_RT_TEST_THREADS);
 171
 172         td = &thread_data[tid];
 173
 174         op = td->opcode;
 175         dat = td->opdata;
 176
 177         switch (op) {
 178         case RTTEST_LOCK:
 179         case RTTEST_LOCKINT:
 180         case RTTEST_LOCKNOWAIT:
 181         case RTTEST_LOCKINTNOWAIT:
 182                 if (mutex != &mutexes[dat])
 183                         break;
 184
 185                 if (td->mutexes[dat] != 1)
 186                         break;
 187
 188                 td->mutexes[dat] = 2;
 189                 td->event = atomic_add_return(1, &rttest_event);
 190                 break;
 191
 192         case RTTEST_LOCKBKL:
 193         default:
 194                 break;
 195         }
 196
 197         schedule();
 198
 199
 200         switch (op) {
 201         case RTTEST_LOCK:
 202         case RTTEST_LOCKINT:
 203                 if (mutex != &mutexes[dat])
 204                         return;
 205
 206                 if (td->mutexes[dat] != 2)
 207                         return;
 208
 209                 td->mutexes[dat] = 3;
 210                 td->event = atomic_add_return(1, &rttest_event);
 211                 break;
 212
 213         case RTTEST_LOCKNOWAIT:
 214         case RTTEST_LOCKINTNOWAIT:
 215                 if (mutex != &mutexes[dat])
 216                         return;
 217
 218                 if (td->mutexes[dat] != 2)
 219                         return;
 220
 221                 td->mutexes[dat] = 1;
 222                 td->event = atomic_add_return(1, &rttest_event);
 223                 return;
 224
 225         case RTTEST_LOCKBKL:
 226                 return;
 227         default:
 228                 return;
 229         }
 230
 231         td->opcode = 0;
 232
 233         for (;;) {
 234                 set_current_state(TASK_INTERRUPTIBLE);
 235
 236                 if (td->opcode > 0) {
 237                         int ret;
 238
 239                         set_current_state(TASK_RUNNING);
 240                         ret = handle_op(td, 1);
 241                         set_current_state(TASK_INTERRUPTIBLE);
 242                         if (td->opcode == RTTEST_LOCKCONT)
 243                                 break;
 244                         td->opcode = ret;
 245                 }
 246
 247                 /* Wait for the next command to be executed */
 248                 schedule();
 249         }
 250
 251         /* Restore previous command and data */
 252         td->opcode = op;
 253         td->opdata = dat;
 254 }
 255
 256 static int test_func(void *data)
 257 {
 258         struct test_thread_data *td = data;
 259         int ret;
 260
 261         current->flags |= PF_MUTEX_TESTER;
 262         allow_signal(SIGHUP);
 263
 264         for(;;) {
 265
 266                 set_current_state(TASK_INTERRUPTIBLE);
 267
 268                 if (td->opcode > 0) {
 269                         set_current_state(TASK_RUNNING);
 270                         ret = handle_op(td, 0);
 271                         set_current_state(TASK_INTERRUPTIBLE);
 272                         td->opcode = ret;
 273                 }
 274
 275                 /* Wait for the next command to be executed */
 276                 schedule();
 277                 try_to_freeze();
 278
 279                 if (signal_pending(current))
 280                         flush_signals(current);
 281
 282                 if(kthread_should_stop())
 283                         break;
 284         }
 285         return 0;
 286 }
 287
 288 /**
 289  * sysfs_test_command - interface for test commands
 290  * @dev:        thread reference
 291  * @buf:        command for actual step
 292  * @count:      length of buffer
 293  *
 294  * command syntax:
 295  *
 296  * opcode:data
 297  */
 298 static ssize_t sysfs_test_command(struct sys_device *dev, const char *buf,
 299                                   size_t count)
 300 {
 301         struct sched_param schedpar;
 302         struct test_thread_data *td;
 303         char cmdbuf[32];
 304         int op, dat, tid, ret;
 305
 306         td = container_of(dev, struct test_thread_data, sysdev);
 307         tid = td->sysdev.id;
 308
 309         /* strings from sysfs write are not 0 terminated! */
 310         if (count >= sizeof(cmdbuf))
 311                 return -EINVAL;
 312
 313         /* strip of \n: */
 314         if (buf[count-1] == '\n')
 315                 count--;
 316         if (count < 1)
 317                 return -EINVAL;
 318
 319         memcpy(cmdbuf, buf, count);
 320         cmdbuf[count] = 0;
 321
 322         if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
 323                 return -EINVAL;
 324
 325         switch (op) {
 326         case RTTEST_SCHEDOT:
 327                 schedpar.sched_priority = 0;
 328                 ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
 329                 if (ret)
 330                         return ret;
 331                 set_user_nice(current, 0);
 332                 break;
 333
 334         case RTTEST_SCHEDRT:
 335                 schedpar.sched_priority = dat;
 336                 ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
 337                 if (ret)
 338                         return ret;
 339                 break;
 340
 341         case RTTEST_SIGNAL:
 342                 send_sig(SIGHUP, threads[tid], 0);
 343                 break;
 344
 345         default:
 346                 if (td->opcode > 0)
 347                         return -EBUSY;
 348                 td->opdata = dat;
 349                 td->opcode = op;
 350                 wake_up_process(threads[tid]);
 351         }
 352
 353         return count;
 354 }
 355
 356 /**
 357  * sysfs_test_status - sysfs interface for rt tester
 358  * @dev:        thread to query
 359  * @buf:        char buffer to be filled with thread status info
 360  */
 361 static ssize_t sysfs_test_status(struct sys_device *dev, char *buf)
 362 {
 363         struct test_thread_data *td;
 364         struct task_struct *tsk;
 365         char *curr = buf;
 366         int i;
 367
 368         td = container_of(dev, struct test_thread_data, sysdev);
 369         tsk = threads[td->sysdev.id];
 370
 371         spin_lock(&rttest_lock);
 372
 373         curr += sprintf(curr,
 374                 "O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, K: %d, M:",
 375                 td->opcode, td->event, tsk->state,
 376                         (MAX_RT_PRIO - 1) - tsk->prio,
 377                         (MAX_RT_PRIO - 1) - tsk->normal_prio,
 378                 tsk->pi_blocked_on, td->bkl);
 379
 380         for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
 381                 curr += sprintf(curr, "%d", td->mutexes[i]);
 382
 383         spin_unlock(&rttest_lock);
 384
 385         curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
 386                         mutexes[td->sysdev.id].owner);
 387
 388         return curr - buf;
 389 }
 390
 391 static SYSDEV_ATTR(status, 0600, sysfs_test_status, NULL);
 392 static SYSDEV_ATTR(command, 0600, NULL, sysfs_test_command);
 393
 394 static struct sysdev_class rttest_sysclass = {
 395         set_kset_name("rttest"),
 396 };
 397
 398 static int init_test_thread(int id)
 399 {
 400         thread_data[id].sysdev.cls = &rttest_sysclass;
 401         thread_data[id].sysdev.id = id;
 402
 403         threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
 404         if (IS_ERR(threads[id]))
 405                 return PTR_ERR(threads[id]);
 406
 407         return sysdev_register(&thread_data[id].sysdev);
 408 }
 409
 410 static int init_rttest(void)
 411 {
 412         int ret, i;
 413
 414         spin_lock_init(&rttest_lock);
 415
 416         for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
 417                 rt_mutex_init(&mutexes[i]);
 418
 419         ret = sysdev_class_register(&rttest_sysclass);
 420         if (ret)
 421                 return ret;
 422
 423         for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
 424                 ret = init_test_thread(i);
 425                 if (ret)
 426                         break;
 427                 ret = sysdev_create_file(&thread_data[i].sysdev, &attr_status);
 428                 if (ret)
 429                         break;
 430                 ret = sysdev_create_file(&thread_data[i].sysdev, &attr_command);
 431                 if (ret)
 432                         break;
 433         }
 434
 435         printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
 436
 437         return ret;
 438 }
 439
 440 device_initcall(init_rttest);