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 long ret; 217 218 if (lock != NULL) 219 spin_unlock_irq(lock); 220 221 DROP_GIANT(); 222 223 task = current; 224 225 /* 226 * Our wait queue entry is on the stack - make sure it doesn't 227 * get swapped out while we sleep. 228 */ 229 #ifndef NO_SWAPPING 230 PHOLD(task->task_thread->td_proc); 231 #endif 232 sleepq_lock(task); 233 if (atomic_load_acq_int(&task->state) != TASK_WAKING) { 234 ret = linux_add_to_sleepqueue(task, "wevent", timeout, state); 235 } else { 236 sleepq_release(task); 237 ret = linux_signal_pending_state(state, task) ? -ERESTARTSYS : 0; 238 } 239 #ifndef NO_SWAPPING 240 PRELE(task->task_thread->td_proc); 241 #endif 242 243 PICKUP_GIANT(); 244 245 if (lock != NULL) 246 spin_lock_irq(lock); 247 return (ret); 248 } 249 250 int 251 linux_schedule_timeout(int timeout) 252 { 253 struct task_struct *task; 254 int state; 255 int remainder; 256 257 task = current; 258 259 /* range check timeout */ 260 if (timeout < 1) 261 timeout = 1; 262 else if (timeout == MAX_SCHEDULE_TIMEOUT) 263 timeout = 0; 264 265 remainder = ticks + timeout; 266 267 DROP_GIANT(); 268 269 sleepq_lock(task); 270 state = atomic_load_acq_int(&task->state); 271 if (state != TASK_WAKING) 272 (void)linux_add_to_sleepqueue(task, "sched", timeout, state); 273 else 274 sleepq_release(task); 275 set_task_state(task, TASK_RUNNING); 276 277 PICKUP_GIANT(); 278 279 if (timeout == 0) 280 return (MAX_SCHEDULE_TIMEOUT); 281 282 /* range check return value */ 283 remainder -= ticks; 284 if (remainder < 0) 285 remainder = 0; 286 else if (remainder > timeout) 287 remainder = timeout; 288 return (remainder); 289 } 290 291 static void 292 wake_up_sleepers(void *wchan) 293 { 294 int wakeup_swapper; 295 296 sleepq_lock(wchan); 297 wakeup_swapper = sleepq_signal(wchan, SLEEPQ_SLEEP, 0, 0); 298 sleepq_release(wchan); 299 if (wakeup_swapper) 300 kick_proc0(); 301 } 302 303 #define bit_to_wchan(word, bit) ((void *)(((uintptr_t)(word) << 6) | (bit))) 304 305 void 306 linux_wake_up_bit(void *word, int bit) 307 { 308 309 wake_up_sleepers(bit_to_wchan(word, bit)); 310 } 311 312 int 313 linux_wait_on_bit_timeout(unsigned long *word, int bit, unsigned int state, 314 int timeout) 315 { 316 struct task_struct *task; 317 void *wchan; 318 int ret; 319 320 DROP_GIANT(); 321 322 /* range check timeout */ 323 if (timeout < 1) 324 timeout = 1; 325 else if (timeout == MAX_SCHEDULE_TIMEOUT) 326 timeout = 0; 327 328 task = current; 329 wchan = bit_to_wchan(word, bit); 330 for (;;) { 331 sleepq_lock(wchan); 332 if ((*word & (1 << bit)) == 0) { 333 sleepq_release(wchan); 334 ret = 0; 335 break; 336 } 337 set_task_state(task, state); 338 ret = linux_add_to_sleepqueue(wchan, "wbit", timeout, state); 339 if (ret != 0) 340 break; 341 } 342 set_task_state(task, TASK_RUNNING); 343 344 PICKUP_GIANT(); 345 346 return (ret); 347 } 348 349 void 350 linux_wake_up_atomic_t(atomic_t *a) 351 { 352 353 wake_up_sleepers(a); 354 } 355 356 int 357 linux_wait_on_atomic_t(atomic_t *a, unsigned int state) 358 { 359 struct task_struct *task; 360 void *wchan; 361 int ret; 362 363 DROP_GIANT(); 364 365 task = current; 366 wchan = a; 367 for (;;) { 368 sleepq_lock(wchan); 369 if (atomic_read(a) == 0) { 370 sleepq_release(wchan); 371 ret = 0; 372 break; 373 } 374 set_task_state(task, state); 375 ret = linux_add_to_sleepqueue(wchan, "watomic", 0, state); 376 if (ret != 0) 377 break; 378 } 379 set_task_state(task, TASK_RUNNING); 380 381 PICKUP_GIANT(); 382 383 return (ret); 384 } 385 386 bool 387 linux_wake_up_state(struct task_struct *task, unsigned int state) 388 { 389 390 return (wake_up_task(task, state) != 0); 391 } 392