xref: /freebsd/lib/libthr/thread/thr_umtx.c (revision aa0a1e58) 
1 /*
2  * Copyright (c) 2005 David Xu <davidxu@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 conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    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 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  * $FreeBSD$
27  *
28  */
29 
30 #include "thr_private.h"
31 #include "thr_umtx.h"
32 
33 #ifndef HAS__UMTX_OP_ERR
34 int _umtx_op_err(void *obj, int op, u_long val, void *uaddr, void *uaddr2)
35 {
36 	if (_umtx_op(obj, op, val, uaddr, uaddr2) == -1)
37 		return (errno);
38 	return (0);
39 }
40 #endif
41 
42 void
43 _thr_umutex_init(struct umutex *mtx)
44 {
45 	static struct umutex default_mtx = DEFAULT_UMUTEX;
46 
47 	*mtx = default_mtx;
48 }
49 
50 void
51 _thr_urwlock_init(struct urwlock *rwl)
52 {
53 	static struct urwlock default_rwl = DEFAULT_URWLOCK;
54 	*rwl = default_rwl;
55 }
56 
57 int
58 __thr_umutex_lock(struct umutex *mtx, uint32_t id)
59 {
60 	uint32_t owner;
61 
62 	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
63 		for (;;) {
64 			/* wait in kernel */
65 			_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);
66 
67 			owner = mtx->m_owner;
68 			if ((owner & ~UMUTEX_CONTESTED) == 0 &&
69 			     atomic_cmpset_acq_32(&mtx->m_owner, owner, id|owner))
70 				return (0);
71 		}
72 	}
73 
74 	return	_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
75 }
76 
77 #define SPINLOOPS 1000
78 
79 int
80 __thr_umutex_lock_spin(struct umutex *mtx, uint32_t id)
81 {
82 	uint32_t owner;
83 
84 	if (!_thr_is_smp)
85 		return __thr_umutex_lock(mtx, id);
86 
87 	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
88 		for (;;) {
89 			int count = SPINLOOPS;
90 			while (count--) {
91 				owner = mtx->m_owner;
92 				if ((owner & ~UMUTEX_CONTESTED) == 0) {
93 					if (atomic_cmpset_acq_32(
94 					    &mtx->m_owner,
95 					    owner, id|owner)) {
96 						return (0);
97 					}
98 				}
99 				CPU_SPINWAIT;
100 			}
101 
102 			/* wait in kernel */
103 			_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);
104 		}
105 	}
106 
107 	return	_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
108 }
109 
110 int
111 __thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
112 	const struct timespec *ets)
113 {
114 	struct timespec timo, cts;
115 	uint32_t owner;
116 	int ret;
117 
118 	clock_gettime(CLOCK_REALTIME, &cts);
119 	TIMESPEC_SUB(&timo, ets, &cts);
120 
121 	if (timo.tv_sec < 0)
122 		return (ETIMEDOUT);
123 
124 	for (;;) {
125 		if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
126 
127 			/* wait in kernel */
128 			ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, &timo);
129 
130 			/* now try to lock it */
131 			owner = mtx->m_owner;
132 			if ((owner & ~UMUTEX_CONTESTED) == 0 &&
133 			     atomic_cmpset_acq_32(&mtx->m_owner, owner, id|owner))
134 				return (0);
135 		} else {
136 			ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, &timo);
137 			if (ret == 0)
138 				break;
139 		}
140 		if (ret == ETIMEDOUT)
141 			break;
142 		clock_gettime(CLOCK_REALTIME, &cts);
143 		TIMESPEC_SUB(&timo, ets, &cts);
144 		if (timo.tv_sec < 0 || (timo.tv_sec == 0 && timo.tv_nsec == 0)) {
145 			ret = ETIMEDOUT;
146 			break;
147 		}
148 	}
149 	return (ret);
150 }
151 
152 int
153 __thr_umutex_unlock(struct umutex *mtx, uint32_t id)
154 {
155 #ifndef __ia64__
156 	/* XXX this logic has a race-condition on ia64. */
157 	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
158 		atomic_cmpset_rel_32(&mtx->m_owner, id | UMUTEX_CONTESTED, UMUTEX_CONTESTED);
159 		return _umtx_op_err(mtx, UMTX_OP_MUTEX_WAKE, 0, 0, 0);
160 	}
161 #endif /* __ia64__ */
162 	return _umtx_op_err(mtx, UMTX_OP_MUTEX_UNLOCK, 0, 0, 0);
163 }
164 
165 int
166 __thr_umutex_trylock(struct umutex *mtx)
167 {
168 	return _umtx_op_err(mtx, UMTX_OP_MUTEX_TRYLOCK, 0, 0, 0);
169 }
170 
171 int
172 __thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
173 	uint32_t *oldceiling)
174 {
175 	return _umtx_op_err(mtx, UMTX_OP_SET_CEILING, ceiling, oldceiling, 0);
176 }
177 
178 int
179 _thr_umtx_wait(volatile long *mtx, long id, const struct timespec *timeout)
180 {
181 	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
182 		timeout->tv_nsec <= 0)))
183 		return (ETIMEDOUT);
184 	return _umtx_op_err(__DEVOLATILE(void *, mtx), UMTX_OP_WAIT, id, 0,
185 		__DECONST(void*, timeout));
186 }
187 
188 int
189 _thr_umtx_wait_uint(volatile u_int *mtx, u_int id, const struct timespec *timeout, int shared)
190 {
191 	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
192 		timeout->tv_nsec <= 0)))
193 		return (ETIMEDOUT);
194 	return _umtx_op_err(__DEVOLATILE(void *, mtx),
195 			shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id, 0,
196 			__DECONST(void*, timeout));
197 }
198 
199 int
200 _thr_umtx_timedwait_uint(volatile u_int *mtx, u_int id, int clockid,
201 	const struct timespec *abstime, int shared)
202 {
203 	struct timespec ts, ts2, *tsp;
204 
205 	if (abstime != NULL) {
206 		clock_gettime(clockid, &ts);
207 		TIMESPEC_SUB(&ts2, abstime, &ts);
208 		if (ts2.tv_sec < 0 || ts2.tv_nsec <= 0)
209 			return (ETIMEDOUT);
210 		tsp = &ts2;
211 	} else {
212 		tsp = NULL;
213 	}
214 	return _umtx_op_err(__DEVOLATILE(void *, mtx),
215 		shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id, NULL,
216 			tsp);
217 }
218 
219 int
220 _thr_umtx_wake(volatile void *mtx, int nr_wakeup, int shared)
221 {
222 	return _umtx_op_err(__DEVOLATILE(void *, mtx), shared ? UMTX_OP_WAKE : UMTX_OP_WAKE_PRIVATE,
223 		nr_wakeup, 0, 0);
224 }
225 
226 void
227 _thr_ucond_init(struct ucond *cv)
228 {
229 	bzero(cv, sizeof(struct ucond));
230 }
231 
232 int
233 _thr_ucond_wait(struct ucond *cv, struct umutex *m,
234 	const struct timespec *timeout, int check_unparking)
235 {
236 	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
237 	    timeout->tv_nsec <= 0))) {
238 		struct pthread *curthread = _get_curthread();
239 		_thr_umutex_unlock(m, TID(curthread));
240                 return (ETIMEDOUT);
241 	}
242 	return _umtx_op_err(cv, UMTX_OP_CV_WAIT,
243 		     check_unparking ? UMTX_CHECK_UNPARKING : 0,
244 		     m, __DECONST(void*, timeout));
245 }
246 
247 int
248 _thr_ucond_signal(struct ucond *cv)
249 {
250 	if (!cv->c_has_waiters)
251 		return (0);
252 	return _umtx_op_err(cv, UMTX_OP_CV_SIGNAL, 0, NULL, NULL);
253 }
254 
255 int
256 _thr_ucond_broadcast(struct ucond *cv)
257 {
258 	if (!cv->c_has_waiters)
259 		return (0);
260 	return _umtx_op_err(cv, UMTX_OP_CV_BROADCAST, 0, NULL, NULL);
261 }
262 
263 int
264 __thr_rwlock_rdlock(struct urwlock *rwlock, int flags, struct timespec *tsp)
265 {
266 	return _umtx_op_err(rwlock, UMTX_OP_RW_RDLOCK, flags, NULL, tsp);
267 }
268 
269 int
270 __thr_rwlock_wrlock(struct urwlock *rwlock, struct timespec *tsp)
271 {
272 	return _umtx_op_err(rwlock, UMTX_OP_RW_WRLOCK, 0, NULL, tsp);
273 }
274 
275 int
276 __thr_rwlock_unlock(struct urwlock *rwlock)
277 {
278 	return _umtx_op_err(rwlock, UMTX_OP_RW_UNLOCK, 0, NULL, NULL);
279 }
280 
281 void
282 _thr_rwl_rdlock(struct urwlock *rwlock)
283 {
284 	int ret;
285 
286 	for (;;) {
287 		if (_thr_rwlock_tryrdlock(rwlock, URWLOCK_PREFER_READER) == 0)
288 			return;
289 		ret = __thr_rwlock_rdlock(rwlock, URWLOCK_PREFER_READER, NULL);
290 		if (ret == 0)
291 			return;
292 		if (ret != EINTR)
293 			PANIC("rdlock error");
294 	}
295 }
296 
297 void
298 _thr_rwl_wrlock(struct urwlock *rwlock)
299 {
300 	int ret;
301 
302 	for (;;) {
303 		if (_thr_rwlock_trywrlock(rwlock) == 0)
304 			return;
305 		ret = __thr_rwlock_wrlock(rwlock, NULL);
306 		if (ret == 0)
307 			return;
308 		if (ret != EINTR)
309 			PANIC("wrlock error");
310 	}
311 }
312 
313 void
314 _thr_rwl_unlock(struct urwlock *rwlock)
315 {
316 	if (_thr_rwlock_unlock(rwlock))
317 		PANIC("unlock error");
318 }
319