sys/compat/linuxkpi/common/src/linux_schedule.c

   1 /*-
   2  * Copyright (c) 2017 Mark Johnston <markj@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conds
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conds, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conds and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/proc.h>
  33 #include <sys/signalvar.h>
  34 #include <sys/sleepqueue.h>
  35
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/list.h>
  39 #include <linux/sched.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/wait.h>
  42
  43 static int
  44 linux_add_to_sleepqueue(void *wchan, const char *wmesg, int timeout, int state)
  45 {
  46         int flags, ret;
  47
  48         MPASS((state & ~TASK_NORMAL) == 0);
  49
  50         flags = SLEEPQ_SLEEP | ((state & TASK_INTERRUPTIBLE) != 0 ?
  51             SLEEPQ_INTERRUPTIBLE : 0);
  52
  53         sleepq_add(wchan, NULL, wmesg, flags, 0);
  54         if (timeout != 0)
  55                 sleepq_set_timeout(wchan, timeout);
  56         if ((state & TASK_INTERRUPTIBLE) != 0) {
  57                 if (timeout == 0)
  58                         ret = -sleepq_wait_sig(wchan, 0);
  59                 else
  60                         ret = -sleepq_timedwait_sig(wchan, 0);
  61         } else {
  62                 if (timeout == 0) {
  63                         sleepq_wait(wchan, 0);
  64                         ret = 0;
  65                 } else
  66                         ret = -sleepq_timedwait(wchan, 0);
  67         }
  68         /* filter return value */
  69         if (ret != 0 && ret != -EWOULDBLOCK)
  70                 ret = -ERESTARTSYS;
  71         return (ret);
  72 }
  73
  74 static int
  75 wake_up_task(struct task_struct *task, unsigned int state)
  76 {
  77         int ret, wakeup_swapper;
  78
  79         ret = wakeup_swapper = 0;
  80         sleepq_lock(task);
  81         if ((atomic_load_acq_int(&task->state) & state) != 0) {
  82                 set_task_state(task, TASK_WAKING);
  83                 wakeup_swapper = sleepq_signal(task, SLEEPQ_SLEEP, 0, 0);
  84                 ret = 1;
  85         }
  86         sleepq_release(task);
  87         if (wakeup_swapper)
  88                 kick_proc0();
  89         return (ret);
  90 }
  91
  92 bool
  93 linux_signal_pending(struct task_struct *task)
  94 {
  95         struct thread *td;
  96         sigset_t pending;
  97
  98         td = task->task_thread;
  99         PROC_LOCK(td->td_proc);
 100         pending = td->td_siglist;
 101         SIGSETOR(pending, td->td_proc->p_siglist);
 102         SIGSETNAND(pending, td->td_sigmask);
 103         PROC_UNLOCK(td->td_proc);
 104         return (!SIGISEMPTY(pending));
 105 }
 106
 107 bool
 108 linux_fatal_signal_pending(struct task_struct *task)
 109 {
 110         struct thread *td;
 111         bool ret;
 112
 113         td = task->task_thread;
 114         PROC_LOCK(td->td_proc);
 115         ret = SIGISMEMBER(td->td_siglist, SIGKILL) ||
 116             SIGISMEMBER(td->td_proc->p_siglist, SIGKILL);
 117         PROC_UNLOCK(td->td_proc);
 118         return (ret);
 119 }
 120
 121 bool
 122 linux_signal_pending_state(long state, struct task_struct *task)
 123 {
 124
 125         MPASS((state & ~TASK_NORMAL) == 0);
 126
 127         if ((state & TASK_INTERRUPTIBLE) == 0)
 128                 return (false);
 129         return (linux_signal_pending(task));
 130 }
 131
 132 void
 133 linux_send_sig(int signo, struct task_struct *task)
 134 {
 135         struct thread *td;
 136
 137         td = task->task_thread;
 138         PROC_LOCK(td->td_proc);
 139         tdsignal(td, signo);
 140         PROC_UNLOCK(td->td_proc);
 141 }
 142
 143 int
 144 autoremove_wake_function(wait_queue_t *wq, unsigned int state, int flags,
 145     void *key __unused)
 146 {
 147         struct task_struct *task;
 148         int ret;
 149
 150         task = wq->private;
 151         if ((ret = wake_up_task(task, state)) != 0)
 152                 list_del_init(&wq->task_list);
 153         return (ret);
 154 }
 155
 156 void
 157 linux_wake_up(wait_queue_head_t *wqh, unsigned int state, int nr, bool locked)
 158 {
 159         wait_queue_t *pos, *next;
 160
 161         if (!locked)
 162                 spin_lock(&wqh->lock);
 163         list_for_each_entry_safe(pos, next, &wqh->task_list, task_list) {
 164                 if (pos->func == NULL) {
 165                         if (wake_up_task(pos->private, state) != 0 && --nr == 0)
 166                                 break;
 167                 } else {
 168                         if (pos->func(pos, state, 0, NULL) != 0 && --nr == 0)
 169                                 break;
 170                 }
 171         }
 172         if (!locked)
 173                 spin_unlock(&wqh->lock);
 174 }
 175
 176 void
 177 linux_prepare_to_wait(wait_queue_head_t *wqh, wait_queue_t *wq, int state)
 178 {
 179
 180         spin_lock(&wqh->lock);
 181         if (list_empty(&wq->task_list))
 182                 __add_wait_queue(wqh, wq);
 183         set_task_state(current, state);
 184         spin_unlock(&wqh->lock);
 185 }
 186
 187 void
 188 linux_finish_wait(wait_queue_head_t *wqh, wait_queue_t *wq)
 189 {
 190
 191         spin_lock(&wqh->lock);
 192         set_task_state(current, TASK_RUNNING);
 193         if (!list_empty(&wq->task_list)) {
 194                 __remove_wait_queue(wqh, wq);
 195                 INIT_LIST_HEAD(&wq->task_list);
 196         }
 197         spin_unlock(&wqh->lock);
 198 }
 199
 200 bool
 201 linux_waitqueue_active(wait_queue_head_t *wqh)
 202 {
 203         bool ret;
 204
 205         spin_lock(&wqh->lock);
 206         ret = !list_empty(&wqh->task_list);
 207         spin_unlock(&wqh->lock);
 208         return (ret);
 209 }
 210
 211 int
 212 linux_wait_event_common(wait_queue_head_t *wqh, wait_queue_t *wq, int timeout,
 213     unsigned int state, spinlock_t *lock)
 214 {
 215         struct task_struct *task;
 216         int ret;
 217
 218         if (lock != NULL)
 219                 spin_unlock_irq(lock);
 220
 221         DROP_GIANT();
 222
 223         /* range check timeout */
 224         if (timeout < 1)
 225                 timeout = 1;
 226         else if (timeout == MAX_SCHEDULE_TIMEOUT)
 227                 timeout = 0;
 228
 229         task = current;
 230
 231         /*
 232          * Our wait queue entry is on the stack - make sure it doesn't
 233          * get swapped out while we sleep.
 234          */
 235 #ifndef NO_SWAPPING
 236         PHOLD(task->task_thread->td_proc);
 237 #endif
 238         sleepq_lock(task);
 239         if (atomic_load_acq_int(&task->state) != TASK_WAKING) {
 240                 ret = linux_add_to_sleepqueue(task, "wevent", timeout, state);
 241         } else {
 242                 sleepq_release(task);
 243                 ret = linux_signal_pending_state(state, task) ? -ERESTARTSYS : 0;
 244         }
 245 #ifndef NO_SWAPPING
 246         PRELE(task->task_thread->td_proc);
 247 #endif
 248
 249         PICKUP_GIANT();
 250
 251         if (lock != NULL)
 252                 spin_lock_irq(lock);
 253         return (ret);
 254 }
 255
 256 int
 257 linux_schedule_timeout(int timeout)
 258 {
 259         struct task_struct *task;
 260         int state;
 261         int remainder;
 262
 263         task = current;
 264
 265         /* range check timeout */
 266         if (timeout < 1)
 267                 timeout = 1;
 268         else if (timeout == MAX_SCHEDULE_TIMEOUT)
 269                 timeout = 0;
 270
 271         remainder = ticks + timeout;
 272
 273         DROP_GIANT();
 274
 275         sleepq_lock(task);
 276         state = atomic_load_acq_int(&task->state);
 277         if (state != TASK_WAKING)
 278                 (void)linux_add_to_sleepqueue(task, "sched", timeout, state);
 279         else
 280                 sleepq_release(task);
 281         set_task_state(task, TASK_RUNNING);
 282
 283         PICKUP_GIANT();
 284
 285         if (timeout == 0)
 286                 return (MAX_SCHEDULE_TIMEOUT);
 287
 288         /* range check return value */
 289         remainder -= ticks;
 290         if (remainder < 0)
 291                 remainder = 0;
 292         else if (remainder > timeout)
 293                 remainder = timeout;
 294         return (remainder);
 295 }
 296
 297 static void
 298 wake_up_sleepers(void *wchan)
 299 {
 300         int wakeup_swapper;
 301
 302         sleepq_lock(wchan);
 303         wakeup_swapper = sleepq_signal(wchan, SLEEPQ_SLEEP, 0, 0);
 304         sleepq_release(wchan);
 305         if (wakeup_swapper)
 306                 kick_proc0();
 307 }
 308
 309 #define bit_to_wchan(word, bit) ((void *)(((uintptr_t)(word) << 6) | (bit)))
 310
 311 void
 312 linux_wake_up_bit(void *word, int bit)
 313 {
 314
 315         wake_up_sleepers(bit_to_wchan(word, bit));
 316 }
 317
 318 int
 319 linux_wait_on_bit_timeout(unsigned long *word, int bit, unsigned int state,
 320     int timeout)
 321 {
 322         struct task_struct *task;
 323         void *wchan;
 324         int ret;
 325
 326         DROP_GIANT();
 327
 328         /* range check timeout */
 329         if (timeout < 1)
 330                 timeout = 1;
 331         else if (timeout == MAX_SCHEDULE_TIMEOUT)
 332                 timeout = 0;
 333
 334         task = current;
 335         wchan = bit_to_wchan(word, bit);
 336         for (;;) {
 337                 sleepq_lock(wchan);
 338                 if ((*word & (1 << bit)) == 0) {
 339                         sleepq_release(wchan);
 340                         ret = 0;
 341                         break;
 342                 }
 343                 set_task_state(task, state);
 344                 ret = linux_add_to_sleepqueue(wchan, "wbit", timeout, state);
 345                 if (ret != 0)
 346                         break;
 347         }
 348         set_task_state(task, TASK_RUNNING);
 349
 350         PICKUP_GIANT();
 351
 352         return (ret);
 353 }
 354
 355 void
 356 linux_wake_up_atomic_t(atomic_t *a)
 357 {
 358
 359         wake_up_sleepers(a);
 360 }
 361
 362 int
 363 linux_wait_on_atomic_t(atomic_t *a, unsigned int state)
 364 {
 365         struct task_struct *task;
 366         void *wchan;
 367         int ret;
 368
 369         DROP_GIANT();
 370
 371         task = current;
 372         wchan = a;
 373         for (;;) {
 374                 sleepq_lock(wchan);
 375                 if (atomic_read(a) == 0) {
 376                         sleepq_release(wchan);
 377                         ret = 0;
 378                         break;
 379                 }
 380                 set_task_state(task, state);
 381                 ret = linux_add_to_sleepqueue(wchan, "watomic", 0, state);
 382                 if (ret != 0)
 383                         break;
 384         }
 385         set_task_state(task, TASK_RUNNING);
 386
 387         PICKUP_GIANT();
 388
 389         return (ret);
 390 }
 391
 392 bool
 393 linux_wake_up_state(struct task_struct *task, unsigned int state)
 394 {
 395
 396         return (wake_up_task(task, state) != 0);
 397 }