LXR linux/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#include <linux/freezer.h>
  17
  18#include "rtmutex.h"
  19
  20#define MAX_RT_TEST_THREADS     8
  21#define MAX_RT_TEST_MUTEXES     8
  22
  23static spinlock_t rttest_lock;
  24static atomic_t rttest_event;
  25
  26struct test_thread_data {
  27        int                     opcode;
  28        int                     opdata;
  29        int                     mutexes[MAX_RT_TEST_MUTEXES];
  30        int                     bkl;
  31        int                     event;
  32        struct sys_device       sysdev;
  33};
  34
  35static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
  36static struct task_struct *threads[MAX_RT_TEST_THREADS];
  37static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];
  38
  39enum test_opcodes {
  40        RTTEST_NOP = 0,
  41        RTTEST_SCHEDOT,         /* 1 Sched other, data = nice */
  42        RTTEST_SCHEDRT,         /* 2 Sched fifo, data = prio */
  43        RTTEST_LOCK,            /* 3 Lock uninterruptible, data = lockindex */
  44        RTTEST_LOCKNOWAIT,      /* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
  45        RTTEST_LOCKINT,         /* 5 Lock interruptible, data = lockindex */
  46        RTTEST_LOCKINTNOWAIT,   /* 6 Lock interruptible no wait in wakeup, data = lockindex */
  47        RTTEST_LOCKCONT,        /* 7 Continue locking after the wakeup delay */
  48        RTTEST_UNLOCK,          /* 8 Unlock, data = lockindex */
  49        RTTEST_LOCKBKL,         /* 9 Lock BKL */
  50        RTTEST_UNLOCKBKL,       /* 10 Unlock BKL */
  51        RTTEST_SIGNAL,          /* 11 Signal other test thread, data = thread id */
  52        RTTEST_RESETEVENT = 98, /* 98 Reset event counter */
  53        RTTEST_RESET = 99,      /* 99 Reset all pending operations */
  54};
  55
  56static int handle_op(struct test_thread_data *td, int lockwakeup)
  57{
  58        int i, id, ret = -EINVAL;
  59
  60        switch(td->opcode) {
  61
  62        case RTTEST_NOP:
  63                return 0;
  64
  65        case RTTEST_LOCKCONT:
  66                td->mutexes[td->opdata] = 1;
  67                td->event = atomic_add_return(1, &rttest_event);
  68                return 0;
  69
  70        case RTTEST_RESET:
  71                for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
  72                        if (td->mutexes[i] == 4) {
  73                                rt_mutex_unlock(&mutexes[i]);
  74                                td->mutexes[i] = 0;
  75                        }
  76                }
  77
  78                if (!lockwakeup && td->bkl == 4) {
  79#ifdef CONFIG_LOCK_KERNEL
  80                        unlock_kernel();
  81#endif
  82                        td->bkl = 0;
  83                }
  84                return 0;
  85
  86        case RTTEST_RESETEVENT:
  87                atomic_set(&rttest_event, 0);
  88                return 0;
  89
  90        default:
  91                if (lockwakeup)
  92                        return ret;
  93        }
  94
  95        switch(td->opcode) {
  96
  97        case RTTEST_LOCK:
  98        case RTTEST_LOCKNOWAIT:
  99                id = td->opdata;
 100                if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
 101                        return ret;
 102
 103                td->mutexes[id] = 1;
 104                td->event = atomic_add_return(1, &rttest_event);
 105                rt_mutex_lock(&mutexes[id]);
 106                td->event = atomic_add_return(1, &rttest_event);
 107                td->mutexes[id] = 4;
 108                return 0;
 109
 110        case RTTEST_LOCKINT:
 111        case RTTEST_LOCKINTNOWAIT:
 112                id = td->opdata;
 113                if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
 114                        return ret;
 115
 116                td->mutexes[id] = 1;
 117                td->event = atomic_add_return(1, &rttest_event);
 118                ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
 119                td->event = atomic_add_return(1, &rttest_event);
 120                td->mutexes[id] = ret ? 0 : 4;
 121                return ret ? -EINTR : 0;
 122
 123        case RTTEST_UNLOCK:
 124                id = td->opdata;
 125                if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
 126                        return ret;
 127
 128                td->event = atomic_add_return(1, &rttest_event);
 129                rt_mutex_unlock(&mutexes[id]);
 130                td->event = atomic_add_return(1, &rttest_event);
 131                td->mutexes[id] = 0;
 132                return 0;
 133
 134        case RTTEST_LOCKBKL:
 135                if (td->bkl)
 136                        return 0;
 137                td->bkl = 1;
 138#ifdef CONFIG_LOCK_KERNEL
 139                lock_kernel();
 140#endif
 141                td->bkl = 4;
 142                return 0;
 143
 144        case RTTEST_UNLOCKBKL:
 145                if (td->bkl != 4)
 146                        break;
 147#ifdef CONFIG_LOCK_KERNEL
 148                unlock_kernel();
 149#endif
 150                td->bkl = 0;
 151                return 0;
 152
 153        default:
 154                break;
 155        }
 156        return ret;
 157}
 158
 159/*
 160 * Schedule replacement for rtsem_down(). Only called for threads with
 161 * PF_MUTEX_TESTER set.
 162 *
 163 * This allows us to have finegrained control over the event flow.
 164 *
 165 */
 166void schedule_rt_mutex_test(struct rt_mutex *mutex)
 167{
 168        int tid, op, dat;
 169        struct test_thread_data *td;
 170
 171        /* We have to lookup the task */
 172        for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
 173                if (threads[tid] == current)
 174                        break;
 175        }
 176
 177        BUG_ON(tid == MAX_RT_TEST_THREADS);
 178
 179        td = &thread_data[tid];
 180
 181        op = td->opcode;
 182        dat = td->opdata;
 183
 184        switch (op) {
 185        case RTTEST_LOCK:
 186        case RTTEST_LOCKINT:
 187        case RTTEST_LOCKNOWAIT:
 188        case RTTEST_LOCKINTNOWAIT:
 189                if (mutex != &mutexes[dat])
 190                        break;
 191
 192                if (td->mutexes[dat] != 1)
 193                        break;
 194
 195                td->mutexes[dat] = 2;
 196                td->event = atomic_add_return(1, &rttest_event);
 197                break;
 198
 199        case RTTEST_LOCKBKL:
 200        default:
 201                break;
 202        }
 203
 204        schedule();
 205
 206
 207        switch (op) {
 208        case RTTEST_LOCK:
 209        case RTTEST_LOCKINT:
 210                if (mutex != &mutexes[dat])
 211                        return;
 212
 213                if (td->mutexes[dat] != 2)
 214                        return;
 215
 216                td->mutexes[dat] = 3;
 217                td->event = atomic_add_return(1, &rttest_event);
 218                break;
 219
 220        case RTTEST_LOCKNOWAIT:
 221        case RTTEST_LOCKINTNOWAIT:
 222                if (mutex != &mutexes[dat])
 223                        return;
 224
 225                if (td->mutexes[dat] != 2)
 226                        return;
 227
 228                td->mutexes[dat] = 1;
 229                td->event = atomic_add_return(1, &rttest_event);
 230                return;
 231
 232        case RTTEST_LOCKBKL:
 233                return;
 234        default:
 235                return;
 236        }
 237
 238        td->opcode = 0;
 239
 240        for (;;) {
 241                set_current_state(TASK_INTERRUPTIBLE);
 242
 243                if (td->opcode > 0) {
 244                        int ret;
 245
 246                        set_current_state(TASK_RUNNING);
 247                        ret = handle_op(td, 1);
 248                        set_current_state(TASK_INTERRUPTIBLE);
 249                        if (td->opcode == RTTEST_LOCKCONT)
 250                                break;
 251                        td->opcode = ret;
 252                }
 253
 254                /* Wait for the next command to be executed */
 255                schedule();
 256        }
 257
 258        /* Restore previous command and data */
 259        td->opcode = op;
 260        td->opdata = dat;
 261}
 262
 263static int test_func(void *data)
 264{
 265        struct test_thread_data *td = data;
 266        int ret;
 267
 268        current->flags |= PF_MUTEX_TESTER;
 269        set_freezable();
 270        allow_signal(SIGHUP);
 271
 272        for(;;) {
 273
 274                set_current_state(TASK_INTERRUPTIBLE);
 275
 276                if (td->opcode > 0) {
 277                        set_current_state(TASK_RUNNING);
 278                        ret = handle_op(td, 0);
 279                        set_current_state(TASK_INTERRUPTIBLE);
 280                        td->opcode = ret;
 281                }
 282
 283                /* Wait for the next command to be executed */
 284                schedule();
 285                try_to_freeze();
 286
 287                if (signal_pending(current))
 288                        flush_signals(current);
 289
 290                if(kthread_should_stop())
 291                        break;
 292        }
 293        return 0;
 294}
 295
 296/**
 297 * sysfs_test_command - interface for test commands
 298 * @dev:        thread reference
 299 * @buf:        command for actual step
 300 * @count:      length of buffer
 301 *
 302 * command syntax:
 303 *
 304 * opcode:data
 305 */
 306static ssize_t sysfs_test_command(struct sys_device *dev, struct sysdev_attribute *attr,
 307                                  const char *buf, size_t count)
 308{
 309        struct sched_param schedpar;
 310        struct test_thread_data *td;
 311        char cmdbuf[32];
 312        int op, dat, tid, ret;
 313
 314        td = container_of(dev, struct test_thread_data, sysdev);
 315        tid = td->sysdev.id;
 316
 317        /* strings from sysfs write are not 0 terminated! */
 318        if (count >= sizeof(cmdbuf))
 319                return -EINVAL;
 320
 321        /* strip of \n: */
 322        if (buf[count-1] == '\n')
 323                count--;
 324        if (count < 1)
 325                return -EINVAL;
 326
 327        memcpy(cmdbuf, buf, count);
 328        cmdbuf[count] = 0;
 329
 330        if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
 331                return -EINVAL;
 332
 333        switch (op) {
 334        case RTTEST_SCHEDOT:
 335                schedpar.sched_priority = 0;
 336                ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
 337                if (ret)
 338                        return ret;
 339                set_user_nice(current, 0);
 340                break;
 341
 342        case RTTEST_SCHEDRT:
 343                schedpar.sched_priority = dat;
 344                ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
 345                if (ret)
 346                        return ret;
 347                break;
 348
 349        case RTTEST_SIGNAL:
 350                send_sig(SIGHUP, threads[tid], 0);
 351                break;
 352
 353        default:
 354                if (td->opcode > 0)
 355                        return -EBUSY;
 356                td->opdata = dat;
 357                td->opcode = op;
 358                wake_up_process(threads[tid]);
 359        }
 360
 361        return count;
 362}
 363
 364/**
 365 * sysfs_test_status - sysfs interface for rt tester
 366 * @dev:        thread to query
 367 * @buf:        char buffer to be filled with thread status info
 368 */
 369static ssize_t sysfs_test_status(struct sys_device *dev, struct sysdev_attribute *attr,
 370                                 char *buf)
 371{
 372        struct test_thread_data *td;
 373        struct task_struct *tsk;
 374        char *curr = buf;
 375        int i;
 376
 377        td = container_of(dev, struct test_thread_data, sysdev);
 378        tsk = threads[td->sysdev.id];
 379
 380        spin_lock(&rttest_lock);
 381
 382        curr += sprintf(curr,
 383                "O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, K: %d, M:",
 384                td->opcode, td->event, tsk->state,
 385                        (MAX_RT_PRIO - 1) - tsk->prio,
 386                        (MAX_RT_PRIO - 1) - tsk->normal_prio,
 387                tsk->pi_blocked_on, td->bkl);
 388
 389        for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
 390                curr += sprintf(curr, "%d", td->mutexes[i]);
 391
 392        spin_unlock(&rttest_lock);
 393
 394        curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
 395                        mutexes[td->sysdev.id].owner);
 396
 397        return curr - buf;
 398}
 399
 400static SYSDEV_ATTR(status, 0600, sysfs_test_status, NULL);
 401static SYSDEV_ATTR(command, 0600, NULL, sysfs_test_command);
 402
 403static struct sysdev_class rttest_sysclass = {
 404        .name = "rttest",
 405};
 406
 407static int init_test_thread(int id)
 408{
 409        thread_data[id].sysdev.cls = &rttest_sysclass;
 410        thread_data[id].sysdev.id = id;
 411
 412        threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
 413        if (IS_ERR(threads[id]))
 414                return PTR_ERR(threads[id]);
 415
 416        return sysdev_register(&thread_data[id].sysdev);
 417}
 418
 419static int init_rttest(void)
 420{
 421        int ret, i;
 422
 423        spin_lock_init(&rttest_lock);
 424
 425        for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
 426                rt_mutex_init(&mutexes[i]);
 427
 428        ret = sysdev_class_register(&rttest_sysclass);
 429        if (ret)
 430                return ret;
 431
 432        for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
 433                ret = init_test_thread(i);
 434                if (ret)
 435                        break;
 436                ret = sysdev_create_file(&thread_data[i].sysdev, &attr_status);
 437                if (ret)
 438                        break;
 439                ret = sysdev_create_file(&thread_data[i].sysdev, &attr_command);
 440                if (ret)
 441                        break;
 442        }
 443
 444        printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
 445
 446        return ret;
 447}
 448
 449device_initcall(init_rttest);
 450