Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/compat/linux/linux_futex.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */ 2 3 /*- 4 * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Emmanuel Dreyfus 17 * 4. The name of the author may not be used to endorse or promote 18 * products derived from this software without specific prior written 19 * permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS'' 22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 #if 0 37 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $"); 38 #endif 39 40 #include "opt_compat.h" 41 42 #include <sys/param.h> 43 #include <sys/types.h> 44 #include <sys/time.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/queue.h> 48 #include <sys/lock.h> 49 #include <sys/mutex.h> 50 #include <sys/sx.h> 51 #include <sys/malloc.h> 52 53 #ifdef COMPAT_LINUX32 54 #include <machine/../linux32/linux.h> 55 #include <machine/../linux32/linux32_proto.h> 56 #else 57 #include <machine/../linux/linux.h> 58 #include <machine/../linux/linux_proto.h> 59 #endif 60 #include <compat/linux/linux_futex.h> 61 62 struct futex; 63 64 struct waiting_proc { 65 struct thread *wp_t; 66 struct futex *wp_new_futex; 67 TAILQ_ENTRY(waiting_proc) wp_list; 68 }; 69 struct futex { 70 void *f_uaddr; 71 int f_refcount; 72 LIST_ENTRY(futex) f_list; 73 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; 74 }; 75 76 LIST_HEAD(futex_list, futex) futex_list; 77 struct sx futex_sx; /* this protects the LIST of futexes */ 78 79 #define FUTEX_LOCK sx_xlock(&futex_sx) 80 #define FUTEX_UNLOCK sx_xunlock(&futex_sx) 81 82 #define FUTEX_LOCKED 1 83 #define FUTEX_UNLOCKED 0 84 85 #define FUTEX_SYSTEM_LOCK mtx_lock(&Giant) 86 #define FUTEX_SYSTEM_UNLOCK mtx_unlock(&Giant) 87 88 static struct futex *futex_get(void *, int); 89 static void futex_put(struct futex *); 90 static int futex_sleep(struct futex *, struct thread *, unsigned long); 91 static int futex_wake(struct futex *, int, struct futex *, int); 92 static int futex_atomic_op(struct thread *td, int encoded_op, caddr_t uaddr); 93 94 /* support.s */ 95 int futex_xchgl(int oparg, caddr_t uaddr, int *oldval); 96 int futex_addl(int oparg, caddr_t uaddr, int *oldval); 97 int futex_orl(int oparg, caddr_t uaddr, int *oldval); 98 int futex_andl(int oparg, caddr_t uaddr, int *oldval); 99 int futex_xorl(int oparg, caddr_t uaddr, int *oldval); 100 101 int 102 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 103 { 104 int val; 105 int ret; 106 struct l_timespec timeout = {0, 0}; 107 int error = 0; 108 struct futex *f; 109 struct futex *newf; 110 int timeout_hz; 111 struct timeval tv = {0, 0}; 112 struct futex *f2; 113 int op_ret; 114 115 #ifdef DEBUG 116 if (ldebug(sys_futex)) 117 printf(ARGS(futex, "%p, %i, %i, *, %p, %i"), args->uaddr, args->op, 118 args->val, args->uaddr2, args->val3); 119 #endif 120 121 switch (args->op) { 122 case LINUX_FUTEX_WAIT: 123 FUTEX_SYSTEM_LOCK; 124 125 if ((error = copyin(args->uaddr, 126 &val, sizeof(val))) != 0) { 127 FUTEX_SYSTEM_UNLOCK; 128 return error; 129 } 130 131 if (val != args->val) { 132 FUTEX_SYSTEM_UNLOCK; 133 return EWOULDBLOCK; 134 } 135 136 if (args->timeout != NULL) { 137 if ((error = copyin(args->timeout, 138 &timeout, sizeof(timeout))) != 0) { 139 FUTEX_SYSTEM_UNLOCK; 140 return error; 141 } 142 } 143 144 #ifdef DEBUG 145 if (ldebug(sys_futex)) 146 printf("FUTEX_WAIT %d: val = %d, uaddr = %p, " 147 "*uaddr = %d, timeout = %d.%09lu\n", 148 td->td_proc->p_pid, args->val, 149 args->uaddr, val, timeout.tv_sec, 150 (unsigned long)timeout.tv_nsec); 151 #endif 152 tv.tv_usec = timeout.tv_sec * 1000000 + timeout.tv_nsec / 1000; 153 timeout_hz = tvtohz(&tv); 154 155 if (timeout.tv_sec == 0 && timeout.tv_nsec == 0) 156 timeout_hz = 0; 157 /* 158 * If the user process requests a non null timeout, 159 * make sure we do not turn it into an infinite 160 * timeout because timeout_hz gets null. 161 * 162 * We use a minimal timeout of 1/hz. Maybe it would 163 * make sense to just return ETIMEDOUT without sleeping. 164 */ 165 if (((timeout.tv_sec != 0) || (timeout.tv_nsec != 0)) && 166 (timeout_hz == 0)) 167 timeout_hz = 1; 168 169 170 f = futex_get(args->uaddr, FUTEX_UNLOCKED); 171 ret = futex_sleep(f, td, timeout_hz); 172 futex_put(f); 173 174 #ifdef DEBUG 175 if (ldebug(sys_futex)) 176 printf("FUTEX_WAIT %d: uaddr = %p, " 177 "ret = %d\n", td->td_proc->p_pid, args->uaddr, ret); 178 #endif 179 180 FUTEX_SYSTEM_UNLOCK; 181 switch (ret) { 182 case EWOULDBLOCK: /* timeout */ 183 return ETIMEDOUT; 184 break; 185 case EINTR: /* signal */ 186 return EINTR; 187 break; 188 case 0: /* FUTEX_WAKE received */ 189 #ifdef DEBUG 190 if (ldebug(sys_futex)) 191 printf("FUTEX_WAIT %d: uaddr = %p, " 192 "got FUTEX_WAKE\n", 193 td->td_proc->p_pid, args->uaddr); 194 #endif 195 return 0; 196 break; 197 default: 198 #ifdef DEBUG 199 if (ldebug(sys_futex)) 200 printf("FUTEX_WAIT: unexpected ret = %d\n", 201 ret); 202 #endif 203 break; 204 } 205 206 /* NOTREACHED */ 207 break; 208 209 case LINUX_FUTEX_WAKE: 210 FUTEX_SYSTEM_LOCK; 211 212 /* 213 * XXX: Linux is able to cope with different addresses 214 * corresponding to the same mapped memory in the sleeping 215 * and waker process(es). 216 */ 217 #ifdef DEBUG 218 if (ldebug(sys_futex)) 219 printf("FUTEX_WAKE %d: uaddr = %p, val = %d\n", 220 td->td_proc->p_pid, args->uaddr, args->val); 221 #endif 222 f = futex_get(args->uaddr, FUTEX_UNLOCKED); 223 td->td_retval[0] = futex_wake(f, args->val, NULL, 0); 224 futex_put(f); 225 226 FUTEX_SYSTEM_UNLOCK; 227 break; 228 229 case LINUX_FUTEX_CMP_REQUEUE: 230 FUTEX_SYSTEM_LOCK; 231 232 if ((error = copyin(args->uaddr, 233 &val, sizeof(val))) != 0) { 234 FUTEX_SYSTEM_UNLOCK; 235 return error; 236 } 237 238 if (val != args->val3) { 239 FUTEX_SYSTEM_UNLOCK; 240 return EAGAIN; 241 } 242 243 f = futex_get(args->uaddr, FUTEX_UNLOCKED); 244 newf = futex_get(args->uaddr2, FUTEX_UNLOCKED); 245 td->td_retval[0] = futex_wake(f, args->val, newf, 246 (int)(unsigned long)args->timeout); 247 futex_put(f); 248 futex_put(newf); 249 250 FUTEX_SYSTEM_UNLOCK; 251 break; 252 253 case LINUX_FUTEX_REQUEUE: 254 FUTEX_SYSTEM_LOCK; 255 256 f = futex_get(args->uaddr, FUTEX_UNLOCKED); 257 newf = futex_get(args->uaddr2, FUTEX_UNLOCKED); 258 td->td_retval[0] = futex_wake(f, args->val, newf, 259 (int)(unsigned long)args->timeout); 260 futex_put(f); 261 futex_put(newf); 262 263 FUTEX_SYSTEM_UNLOCK; 264 break; 265 266 case LINUX_FUTEX_FD: 267 /* XXX: Linux plans to remove this operation */ 268 printf("linux_sys_futex: unimplemented op %d\n", 269 args->op); 270 break; 271 272 case LINUX_FUTEX_WAKE_OP: 273 FUTEX_SYSTEM_LOCK; 274 #ifdef DEBUG 275 if (ldebug(sys_futex)) 276 printf("FUTEX_WAKE_OP: %d: uaddr = %p, op = %d, " 277 "val = %x, uaddr2 = %p, val3 = %x\n", 278 td->td_proc->p_pid, args->uaddr, args->op, 279 args->val, args->uaddr2, args->val3); 280 #endif 281 f = futex_get(args->uaddr, FUTEX_UNLOCKED); 282 f2 = futex_get(args->uaddr2, FUTEX_UNLOCKED); 283 284 /* 285 * This function returns positive number as results and 286 * negative as errors 287 */ 288 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 289 #ifdef DEBUG 290 if (ldebug(sys_futex)) 291 printf("futex_atomic_op ret %d\n", op_ret); 292 #endif 293 if (op_ret < 0) { 294 /* XXX: We don't handle the EFAULT yet. */ 295 if (op_ret != -EFAULT) { 296 futex_put(f); 297 futex_put(f2); 298 FUTEX_SYSTEM_UNLOCK; 299 return (-op_ret); 300 } 301 302 futex_put(f); 303 futex_put(f2); 304 305 FUTEX_SYSTEM_UNLOCK; 306 return (EFAULT); 307 } 308 309 ret = futex_wake(f, args->val, NULL, 0); 310 futex_put(f); 311 if (op_ret > 0) { 312 op_ret = 0; 313 /* 314 * Linux abuses the address of the timespec parameter 315 * as the number of retries. 316 */ 317 op_ret += futex_wake(f2, 318 (int)(unsigned long)args->timeout, NULL, 0); 319 ret += op_ret; 320 } 321 futex_put(f2); 322 td->td_retval[0] = ret; 323 324 FUTEX_SYSTEM_UNLOCK; 325 break; 326 327 default: 328 printf("linux_sys_futex: unknown op %d\n", 329 args->op); 330 break; 331 } 332 return (0); 333 } 334 335 static struct futex * 336 futex_get(void *uaddr, int locked) 337 { 338 struct futex *f; 339 340 if (locked == FUTEX_UNLOCKED) 341 FUTEX_LOCK; 342 LIST_FOREACH(f, &futex_list, f_list) { 343 if (f->f_uaddr == uaddr) { 344 f->f_refcount++; 345 if (locked == FUTEX_UNLOCKED) 346 FUTEX_UNLOCK; 347 return f; 348 } 349 } 350 351 f = malloc(sizeof(*f), M_LINUX, M_WAITOK); 352 f->f_uaddr = uaddr; 353 f->f_refcount = 1; 354 TAILQ_INIT(&f->f_waiting_proc); 355 LIST_INSERT_HEAD(&futex_list, f, f_list); 356 if (locked == FUTEX_UNLOCKED) 357 FUTEX_UNLOCK; 358 359 return f; 360 } 361 362 static void 363 futex_put(f) 364 struct futex *f; 365 { 366 FUTEX_LOCK; 367 f->f_refcount--; 368 if (f->f_refcount == 0) { 369 LIST_REMOVE(f, f_list); 370 free(f, M_LINUX); 371 } 372 FUTEX_UNLOCK; 373 374 return; 375 } 376 377 static int 378 futex_sleep(struct futex *f, struct thread *td, unsigned long timeout) 379 { 380 struct waiting_proc *wp; 381 int ret; 382 383 wp = malloc(sizeof(*wp), M_LINUX, M_WAITOK); 384 wp->wp_t = td; 385 wp->wp_new_futex = NULL; 386 FUTEX_LOCK; 387 TAILQ_INSERT_TAIL(&f->f_waiting_proc, wp, wp_list); 388 FUTEX_UNLOCK; 389 390 #ifdef DEBUG 391 if (ldebug(sys_futex)) 392 printf("FUTEX --> %d tlseep timeout = %ld\n", 393 td->td_proc->p_pid, timeout); 394 #endif 395 ret = tsleep(wp, PCATCH | PZERO, "linuxfutex", timeout); 396 #ifdef DEBUG 397 if (ldebug(sys_futex)) 398 printf("FUTEX -> %d tsleep returns %d\n", 399 td->td_proc->p_pid, ret); 400 #endif 401 402 FUTEX_LOCK; 403 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 404 FUTEX_UNLOCK; 405 406 /* if we got woken up in futex_wake */ 407 if ((ret == 0) && (wp->wp_new_futex != NULL)) { 408 /* suspend us on the new futex */ 409 ret = futex_sleep(wp->wp_new_futex, td, timeout); 410 /* and release the old one */ 411 futex_put(wp->wp_new_futex); 412 } 413 414 free(wp, M_LINUX); 415 416 return ret; 417 } 418 419 static int 420 futex_wake(struct futex *f, int n, struct futex *newf, int n2) 421 { 422 struct waiting_proc *wp; 423 int count; 424 425 /* 426 * Linux is very strange it wakes up N threads for 427 * all operations BUT requeue ones where its N+1 428 * mimic this. 429 */ 430 count = newf ? 0 : 1; 431 432 FUTEX_LOCK; 433 TAILQ_FOREACH(wp, &f->f_waiting_proc, wp_list) { 434 if (count <= n) { 435 wakeup_one(wp); 436 count++; 437 } else { 438 if (newf != NULL) { 439 /* futex_put called after tsleep */ 440 wp->wp_new_futex = futex_get(newf->f_uaddr, 441 FUTEX_LOCKED); 442 wakeup_one(wp); 443 if (count - n >= n2) 444 break; 445 } 446 } 447 } 448 FUTEX_UNLOCK; 449 450 return count; 451 } 452 453 static int 454 futex_atomic_op(struct thread *td, int encoded_op, caddr_t uaddr) 455 { 456 int op = (encoded_op >> 28) & 7; 457 int cmp = (encoded_op >> 24) & 15; 458 int oparg = (encoded_op << 8) >> 20; 459 int cmparg = (encoded_op << 20) >> 20; 460 int oldval = 0, ret; 461 462 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 463 oparg = 1 << oparg; 464 465 #ifdef DEBUG 466 if (ldebug(sys_futex)) 467 printf("futex_atomic_op: op = %d, cmp = %d, oparg = %x, " 468 "cmparg = %x, uaddr = %p\n", 469 op, cmp, oparg, cmparg, uaddr); 470 #endif 471 /* XXX: linux verifies access here and returns EFAULT */ 472 473 switch (op) { 474 case FUTEX_OP_SET: 475 ret = futex_xchgl(oparg, uaddr, &oldval); 476 break; 477 case FUTEX_OP_ADD: 478 ret = futex_addl(oparg, uaddr, &oldval); 479 break; 480 case FUTEX_OP_OR: 481 ret = futex_orl(oparg, uaddr, &oldval); 482 break; 483 case FUTEX_OP_ANDN: 484 ret = futex_andl(~oparg, uaddr, &oldval); 485 break; 486 case FUTEX_OP_XOR: 487 ret = futex_xorl(oparg, uaddr, &oldval); 488 break; 489 default: 490 ret = -ENOSYS; 491 break; 492 } 493 494 if (ret) 495 return (ret); 496 497 switch (cmp) { 498 case FUTEX_OP_CMP_EQ: 499 return (oldval == cmparg); 500 case FUTEX_OP_CMP_NE: 501 return (oldval != cmparg); 502 case FUTEX_OP_CMP_LT: 503 return (oldval < cmparg); 504 case FUTEX_OP_CMP_GE: 505 return (oldval >= cmparg); 506 case FUTEX_OP_CMP_LE: 507 return (oldval <= cmparg); 508 case FUTEX_OP_CMP_GT: 509 return (oldval > cmparg); 510 default: 511 return (-ENOSYS); 512 } 513 }
Cache object: 80d115c266535f8dcc1381d9926090be
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]