The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kernel/rtmutex-tester.c

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

Cache object: 79bf858285bac8d0509da3451f4f3189


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