1 /* $NetBSD: locks.c,v 1.54 2011/03/21 16:41:08 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2007-2011 Antti Kantee. 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 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __KERNEL_RCSID(0, "$NetBSD: locks.c,v 1.54 2011/03/21 16:41:08 pooka Exp $"); 30 31 #include <sys/param.h> 32 #include <sys/kmem.h> 33 #include <sys/mutex.h> 34 #include <sys/rwlock.h> 35 36 #include <rump/rumpuser.h> 37 38 #include "rump_private.h" 39 40 /* 41 * Simple lockdebug. If it's compiled in, it's always active. 42 * Currently available only for mtx/rwlock. 43 */ 44 #ifdef LOCKDEBUG 45 #include <sys/lockdebug.h> 46 47 static lockops_t mutex_lockops = { 48 "mutex", 49 LOCKOPS_SLEEP, 50 NULL 51 }; 52 static lockops_t rw_lockops = { 53 "rwlock", 54 LOCKOPS_SLEEP, 55 NULL 56 }; 57 58 #define ALLOCK(lock, ops) \ 59 lockdebug_alloc(lock, ops, (uintptr_t)__builtin_return_address(0)) 60 #define FREELOCK(lock) \ 61 lockdebug_free(lock) 62 #define WANTLOCK(lock, shar, try) \ 63 lockdebug_wantlock(lock, (uintptr_t)__builtin_return_address(0), shar, try) 64 #define LOCKED(lock, shar) \ 65 lockdebug_locked(lock, NULL, (uintptr_t)__builtin_return_address(0), shar) 66 #define UNLOCKED(lock, shar) \ 67 lockdebug_unlocked(lock, (uintptr_t)__builtin_return_address(0), shar) 68 #else 69 #define ALLOCK(a, b) 70 #define FREELOCK(a) 71 #define WANTLOCK(a, b, c) 72 #define LOCKED(a, b) 73 #define UNLOCKED(a, b) 74 #endif 75 76 /* 77 * We map locks to pthread routines. The difference between kernel 78 * and rumpuser routines is that while the kernel uses static 79 * storage, rumpuser allocates the object from the heap. This 80 * indirection is necessary because we don't know the size of 81 * pthread objects here. It is also beneficial, since we can 82 * be easily compatible with the kernel ABI because all kernel 83 * objects regardless of machine architecture are always at least 84 * the size of a pointer. The downside, of course, is a performance 85 * penalty. 86 */ 87 88 #define RUMPMTX(mtx) (*(struct rumpuser_mtx **)(mtx)) 89 90 void 91 mutex_init(kmutex_t *mtx, kmutex_type_t type, int ipl) 92 { 93 94 CTASSERT(sizeof(kmutex_t) >= sizeof(void *)); 95 96 rumpuser_mutex_init_kmutex((struct rumpuser_mtx **)mtx); 97 ALLOCK(mtx, &mutex_lockops); 98 } 99 100 void 101 mutex_destroy(kmutex_t *mtx) 102 { 103 104 FREELOCK(mtx); 105 rumpuser_mutex_destroy(RUMPMTX(mtx)); 106 } 107 108 void 109 mutex_enter(kmutex_t *mtx) 110 { 111 112 WANTLOCK(mtx, false, false); 113 rumpuser_mutex_enter(RUMPMTX(mtx)); 114 LOCKED(mtx, false); 115 } 116 __strong_alias(mutex_spin_enter,mutex_enter); 117 118 int 119 mutex_tryenter(kmutex_t *mtx) 120 { 121 int rv; 122 123 rv = rumpuser_mutex_tryenter(RUMPMTX(mtx)); 124 if (rv) { 125 WANTLOCK(mtx, false, true); 126 LOCKED(mtx, false); 127 } 128 return rv; 129 } 130 131 void 132 mutex_exit(kmutex_t *mtx) 133 { 134 135 UNLOCKED(mtx, false); 136 rumpuser_mutex_exit(RUMPMTX(mtx)); 137 } 138 __strong_alias(mutex_spin_exit,mutex_exit); 139 140 int 141 mutex_owned(kmutex_t *mtx) 142 { 143 144 return mutex_owner(mtx) == curlwp; 145 } 146 147 struct lwp * 148 mutex_owner(kmutex_t *mtx) 149 { 150 151 return rumpuser_mutex_owner(RUMPMTX(mtx)); 152 } 153 154 #define RUMPRW(rw) (*(struct rumpuser_rw **)(rw)) 155 156 /* reader/writer locks */ 157 158 void 159 rw_init(krwlock_t *rw) 160 { 161 162 CTASSERT(sizeof(krwlock_t) >= sizeof(void *)); 163 164 rumpuser_rw_init((struct rumpuser_rw **)rw); 165 ALLOCK(rw, &rw_lockops); 166 } 167 168 void 169 rw_destroy(krwlock_t *rw) 170 { 171 172 FREELOCK(rw); 173 rumpuser_rw_destroy(RUMPRW(rw)); 174 } 175 176 void 177 rw_enter(krwlock_t *rw, const krw_t op) 178 { 179 180 181 WANTLOCK(rw, op == RW_READER, false); 182 rumpuser_rw_enter(RUMPRW(rw), op == RW_WRITER); 183 LOCKED(rw, op == RW_READER); 184 } 185 186 int 187 rw_tryenter(krwlock_t *rw, const krw_t op) 188 { 189 int rv; 190 191 rv = rumpuser_rw_tryenter(RUMPRW(rw), op == RW_WRITER); 192 if (rv) { 193 WANTLOCK(rw, op == RW_READER, true); 194 LOCKED(rw, op == RW_READER); 195 } 196 return rv; 197 } 198 199 void 200 rw_exit(krwlock_t *rw) 201 { 202 203 #ifdef LOCKDEBUG 204 bool shared = !rw_write_held(rw); 205 206 if (shared) 207 KASSERT(rw_read_held(rw)); 208 UNLOCKED(rw, shared); 209 #endif 210 rumpuser_rw_exit(RUMPRW(rw)); 211 } 212 213 /* always fails */ 214 int 215 rw_tryupgrade(krwlock_t *rw) 216 { 217 218 return 0; 219 } 220 221 void 222 rw_downgrade(krwlock_t *rw) 223 { 224 225 #ifdef LOCKDEBUG 226 KASSERT(!rw_write_held(rw)); 227 #endif 228 /* 229 * XXX HACK: How we can downgrade re lock in rump properly. 230 */ 231 rw_exit(rw); 232 rw_enter(rw, RW_READER); 233 return; 234 } 235 236 int 237 rw_write_held(krwlock_t *rw) 238 { 239 240 return rumpuser_rw_wrheld(RUMPRW(rw)); 241 } 242 243 int 244 rw_read_held(krwlock_t *rw) 245 { 246 247 return rumpuser_rw_rdheld(RUMPRW(rw)); 248 } 249 250 int 251 rw_lock_held(krwlock_t *rw) 252 { 253 254 return rumpuser_rw_held(RUMPRW(rw)); 255 } 256 257 /* curriculum vitaes */ 258 259 #define RUMPCV(cv) (*(struct rumpuser_cv **)(cv)) 260 261 void 262 cv_init(kcondvar_t *cv, const char *msg) 263 { 264 265 CTASSERT(sizeof(kcondvar_t) >= sizeof(void *)); 266 267 rumpuser_cv_init((struct rumpuser_cv **)cv); 268 } 269 270 void 271 cv_destroy(kcondvar_t *cv) 272 { 273 274 rumpuser_cv_destroy(RUMPCV(cv)); 275 } 276 277 static int 278 docvwait(kcondvar_t *cv, kmutex_t *mtx, struct timespec *ts) 279 { 280 struct lwp *l = curlwp; 281 int rv; 282 283 if (__predict_false(l->l_flag & LW_RUMP_QEXIT)) { 284 /* 285 * yield() here, someone might want the cpu 286 * to set a condition. otherwise we'll just 287 * loop forever. 288 */ 289 yield(); 290 return EINTR; 291 } 292 293 UNLOCKED(mtx, false); 294 295 l->l_private = cv; 296 rv = 0; 297 if (ts) { 298 if (rumpuser_cv_timedwait(RUMPCV(cv), RUMPMTX(mtx), 299 ts->tv_sec, ts->tv_nsec)) 300 rv = EWOULDBLOCK; 301 } else { 302 rumpuser_cv_wait(RUMPCV(cv), RUMPMTX(mtx)); 303 } 304 305 LOCKED(mtx, false); 306 307 /* 308 * Check for QEXIT. if so, we need to wait here until we 309 * are allowed to exit. 310 */ 311 if (__predict_false(l->l_flag & LW_RUMP_QEXIT)) { 312 struct proc *p = l->l_proc; 313 314 UNLOCKED(mtx, false); 315 mutex_exit(mtx); /* drop and retake later */ 316 317 mutex_enter(p->p_lock); 318 while ((p->p_sflag & PS_RUMP_LWPEXIT) == 0) { 319 /* avoid recursion */ 320 rumpuser_cv_wait(RUMPCV(&p->p_waitcv), 321 RUMPMTX(p->p_lock)); 322 } 323 KASSERT(p->p_sflag & PS_RUMP_LWPEXIT); 324 mutex_exit(p->p_lock); 325 326 /* ok, we can exit and remove "reference" to l->private */ 327 328 mutex_enter(mtx); 329 LOCKED(mtx, false); 330 rv = EINTR; 331 } 332 l->l_private = NULL; 333 334 return rv; 335 } 336 337 void 338 cv_wait(kcondvar_t *cv, kmutex_t *mtx) 339 { 340 341 if (__predict_false(rump_threads == 0)) 342 panic("cv_wait without threads"); 343 (void) docvwait(cv, mtx, NULL); 344 } 345 346 int 347 cv_wait_sig(kcondvar_t *cv, kmutex_t *mtx) 348 { 349 350 if (__predict_false(rump_threads == 0)) 351 panic("cv_wait without threads"); 352 return docvwait(cv, mtx, NULL); 353 } 354 355 int 356 cv_timedwait(kcondvar_t *cv, kmutex_t *mtx, int ticks) 357 { 358 struct timespec ts, tick; 359 extern int hz; 360 int rv; 361 362 if (ticks == 0) { 363 rv = cv_wait_sig(cv, mtx); 364 } else { 365 /* 366 * XXX: this fetches rump kernel time, but 367 * rumpuser_cv_timedwait uses host time. 368 */ 369 nanotime(&ts); 370 tick.tv_sec = ticks / hz; 371 tick.tv_nsec = (ticks % hz) * (1000000000/hz); 372 timespecadd(&ts, &tick, &ts); 373 374 rv = docvwait(cv, mtx, &ts); 375 } 376 377 return rv; 378 } 379 __strong_alias(cv_timedwait_sig,cv_timedwait); 380 381 void 382 cv_signal(kcondvar_t *cv) 383 { 384 385 rumpuser_cv_signal(RUMPCV(cv)); 386 } 387 388 void 389 cv_broadcast(kcondvar_t *cv) 390 { 391 392 rumpuser_cv_broadcast(RUMPCV(cv)); 393 } 394 395 bool 396 cv_has_waiters(kcondvar_t *cv) 397 { 398 399 return rumpuser_cv_has_waiters(RUMPCV(cv)); 400 } 401 402 /* this is not much of an attempt, but ... */ 403 bool 404 cv_is_valid(kcondvar_t *cv) 405 { 406 407 return RUMPCV(cv) != NULL; 408 } 409