ppc/pnv: Add support for POWER8+ LPC Controller
[qemu.git] / util / qemu-thread-posix.c
1 /*
2 * Wrappers around mutex/cond/thread functions
3 *
4 * Copyright Red Hat, Inc. 2009
5 *
6 * Author:
7 * Marcelo Tosatti <mtosatti@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 *
12 */
13 #include "qemu/osdep.h"
14 #include "qemu/thread.h"
15 #include "qemu/atomic.h"
16 #include "qemu/notify.h"
17
18 static bool name_threads;
19
20 void qemu_thread_naming(bool enable)
21 {
22 name_threads = enable;
23
24 #ifndef CONFIG_THREAD_SETNAME_BYTHREAD
25 /* This is a debugging option, not fatal */
26 if (enable) {
27 fprintf(stderr, "qemu: thread naming not supported on this host\n");
28 }
29 #endif
30 }
31
32 static void error_exit(int err, const char *msg)
33 {
34 fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err));
35 abort();
36 }
37
38 void qemu_mutex_init(QemuMutex *mutex)
39 {
40 int err;
41
42 err = pthread_mutex_init(&mutex->lock, NULL);
43 if (err)
44 error_exit(err, __func__);
45 }
46
47 void qemu_mutex_destroy(QemuMutex *mutex)
48 {
49 int err;
50
51 err = pthread_mutex_destroy(&mutex->lock);
52 if (err)
53 error_exit(err, __func__);
54 }
55
56 void qemu_mutex_lock(QemuMutex *mutex)
57 {
58 int err;
59
60 err = pthread_mutex_lock(&mutex->lock);
61 if (err)
62 error_exit(err, __func__);
63 }
64
65 int qemu_mutex_trylock(QemuMutex *mutex)
66 {
67 return pthread_mutex_trylock(&mutex->lock);
68 }
69
70 void qemu_mutex_unlock(QemuMutex *mutex)
71 {
72 int err;
73
74 err = pthread_mutex_unlock(&mutex->lock);
75 if (err)
76 error_exit(err, __func__);
77 }
78
79 void qemu_rec_mutex_init(QemuRecMutex *mutex)
80 {
81 int err;
82 pthread_mutexattr_t attr;
83
84 pthread_mutexattr_init(&attr);
85 pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
86 err = pthread_mutex_init(&mutex->lock, &attr);
87 pthread_mutexattr_destroy(&attr);
88 if (err) {
89 error_exit(err, __func__);
90 }
91 }
92
93 void qemu_cond_init(QemuCond *cond)
94 {
95 int err;
96
97 err = pthread_cond_init(&cond->cond, NULL);
98 if (err)
99 error_exit(err, __func__);
100 }
101
102 void qemu_cond_destroy(QemuCond *cond)
103 {
104 int err;
105
106 err = pthread_cond_destroy(&cond->cond);
107 if (err)
108 error_exit(err, __func__);
109 }
110
111 void qemu_cond_signal(QemuCond *cond)
112 {
113 int err;
114
115 err = pthread_cond_signal(&cond->cond);
116 if (err)
117 error_exit(err, __func__);
118 }
119
120 void qemu_cond_broadcast(QemuCond *cond)
121 {
122 int err;
123
124 err = pthread_cond_broadcast(&cond->cond);
125 if (err)
126 error_exit(err, __func__);
127 }
128
129 void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex)
130 {
131 int err;
132
133 err = pthread_cond_wait(&cond->cond, &mutex->lock);
134 if (err)
135 error_exit(err, __func__);
136 }
137
138 void qemu_sem_init(QemuSemaphore *sem, int init)
139 {
140 int rc;
141
142 #if defined(__APPLE__) || defined(__NetBSD__)
143 rc = pthread_mutex_init(&sem->lock, NULL);
144 if (rc != 0) {
145 error_exit(rc, __func__);
146 }
147 rc = pthread_cond_init(&sem->cond, NULL);
148 if (rc != 0) {
149 error_exit(rc, __func__);
150 }
151 if (init < 0) {
152 error_exit(EINVAL, __func__);
153 }
154 sem->count = init;
155 #else
156 rc = sem_init(&sem->sem, 0, init);
157 if (rc < 0) {
158 error_exit(errno, __func__);
159 }
160 #endif
161 }
162
163 void qemu_sem_destroy(QemuSemaphore *sem)
164 {
165 int rc;
166
167 #if defined(__APPLE__) || defined(__NetBSD__)
168 rc = pthread_cond_destroy(&sem->cond);
169 if (rc < 0) {
170 error_exit(rc, __func__);
171 }
172 rc = pthread_mutex_destroy(&sem->lock);
173 if (rc < 0) {
174 error_exit(rc, __func__);
175 }
176 #else
177 rc = sem_destroy(&sem->sem);
178 if (rc < 0) {
179 error_exit(errno, __func__);
180 }
181 #endif
182 }
183
184 void qemu_sem_post(QemuSemaphore *sem)
185 {
186 int rc;
187
188 #if defined(__APPLE__) || defined(__NetBSD__)
189 pthread_mutex_lock(&sem->lock);
190 if (sem->count == UINT_MAX) {
191 rc = EINVAL;
192 } else {
193 sem->count++;
194 rc = pthread_cond_signal(&sem->cond);
195 }
196 pthread_mutex_unlock(&sem->lock);
197 if (rc != 0) {
198 error_exit(rc, __func__);
199 }
200 #else
201 rc = sem_post(&sem->sem);
202 if (rc < 0) {
203 error_exit(errno, __func__);
204 }
205 #endif
206 }
207
208 static void compute_abs_deadline(struct timespec *ts, int ms)
209 {
210 struct timeval tv;
211 gettimeofday(&tv, NULL);
212 ts->tv_nsec = tv.tv_usec * 1000 + (ms % 1000) * 1000000;
213 ts->tv_sec = tv.tv_sec + ms / 1000;
214 if (ts->tv_nsec >= 1000000000) {
215 ts->tv_sec++;
216 ts->tv_nsec -= 1000000000;
217 }
218 }
219
220 int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
221 {
222 int rc;
223 struct timespec ts;
224
225 #if defined(__APPLE__) || defined(__NetBSD__)
226 rc = 0;
227 compute_abs_deadline(&ts, ms);
228 pthread_mutex_lock(&sem->lock);
229 while (sem->count == 0) {
230 rc = pthread_cond_timedwait(&sem->cond, &sem->lock, &ts);
231 if (rc == ETIMEDOUT) {
232 break;
233 }
234 if (rc != 0) {
235 error_exit(rc, __func__);
236 }
237 }
238 if (rc != ETIMEDOUT) {
239 --sem->count;
240 }
241 pthread_mutex_unlock(&sem->lock);
242 return (rc == ETIMEDOUT ? -1 : 0);
243 #else
244 if (ms <= 0) {
245 /* This is cheaper than sem_timedwait. */
246 do {
247 rc = sem_trywait(&sem->sem);
248 } while (rc == -1 && errno == EINTR);
249 if (rc == -1 && errno == EAGAIN) {
250 return -1;
251 }
252 } else {
253 compute_abs_deadline(&ts, ms);
254 do {
255 rc = sem_timedwait(&sem->sem, &ts);
256 } while (rc == -1 && errno == EINTR);
257 if (rc == -1 && errno == ETIMEDOUT) {
258 return -1;
259 }
260 }
261 if (rc < 0) {
262 error_exit(errno, __func__);
263 }
264 return 0;
265 #endif
266 }
267
268 void qemu_sem_wait(QemuSemaphore *sem)
269 {
270 int rc;
271
272 #if defined(__APPLE__) || defined(__NetBSD__)
273 pthread_mutex_lock(&sem->lock);
274 while (sem->count == 0) {
275 rc = pthread_cond_wait(&sem->cond, &sem->lock);
276 if (rc != 0) {
277 error_exit(rc, __func__);
278 }
279 }
280 --sem->count;
281 pthread_mutex_unlock(&sem->lock);
282 #else
283 do {
284 rc = sem_wait(&sem->sem);
285 } while (rc == -1 && errno == EINTR);
286 if (rc < 0) {
287 error_exit(errno, __func__);
288 }
289 #endif
290 }
291
292 #ifdef __linux__
293 #include "qemu/futex.h"
294 #else
295 static inline void qemu_futex_wake(QemuEvent *ev, int n)
296 {
297 pthread_mutex_lock(&ev->lock);
298 if (n == 1) {
299 pthread_cond_signal(&ev->cond);
300 } else {
301 pthread_cond_broadcast(&ev->cond);
302 }
303 pthread_mutex_unlock(&ev->lock);
304 }
305
306 static inline void qemu_futex_wait(QemuEvent *ev, unsigned val)
307 {
308 pthread_mutex_lock(&ev->lock);
309 if (ev->value == val) {
310 pthread_cond_wait(&ev->cond, &ev->lock);
311 }
312 pthread_mutex_unlock(&ev->lock);
313 }
314 #endif
315
316 /* Valid transitions:
317 * - free->set, when setting the event
318 * - busy->set, when setting the event, followed by qemu_futex_wake
319 * - set->free, when resetting the event
320 * - free->busy, when waiting
321 *
322 * set->busy does not happen (it can be observed from the outside but
323 * it really is set->free->busy).
324 *
325 * busy->free provably cannot happen; to enforce it, the set->free transition
326 * is done with an OR, which becomes a no-op if the event has concurrently
327 * transitioned to free or busy.
328 */
329
330 #define EV_SET 0
331 #define EV_FREE 1
332 #define EV_BUSY -1
333
334 void qemu_event_init(QemuEvent *ev, bool init)
335 {
336 #ifndef __linux__
337 pthread_mutex_init(&ev->lock, NULL);
338 pthread_cond_init(&ev->cond, NULL);
339 #endif
340
341 ev->value = (init ? EV_SET : EV_FREE);
342 }
343
344 void qemu_event_destroy(QemuEvent *ev)
345 {
346 #ifndef __linux__
347 pthread_mutex_destroy(&ev->lock);
348 pthread_cond_destroy(&ev->cond);
349 #endif
350 }
351
352 void qemu_event_set(QemuEvent *ev)
353 {
354 /* qemu_event_set has release semantics, but because it *loads*
355 * ev->value we need a full memory barrier here.
356 */
357 smp_mb();
358 if (atomic_read(&ev->value) != EV_SET) {
359 if (atomic_xchg(&ev->value, EV_SET) == EV_BUSY) {
360 /* There were waiters, wake them up. */
361 qemu_futex_wake(ev, INT_MAX);
362 }
363 }
364 }
365
366 void qemu_event_reset(QemuEvent *ev)
367 {
368 unsigned value;
369
370 value = atomic_read(&ev->value);
371 smp_mb_acquire();
372 if (value == EV_SET) {
373 /*
374 * If there was a concurrent reset (or even reset+wait),
375 * do nothing. Otherwise change EV_SET->EV_FREE.
376 */
377 atomic_or(&ev->value, EV_FREE);
378 }
379 }
380
381 void qemu_event_wait(QemuEvent *ev)
382 {
383 unsigned value;
384
385 value = atomic_read(&ev->value);
386 smp_mb_acquire();
387 if (value != EV_SET) {
388 if (value == EV_FREE) {
389 /*
390 * Leave the event reset and tell qemu_event_set that there
391 * are waiters. No need to retry, because there cannot be
392 * a concurrent busy->free transition. After the CAS, the
393 * event will be either set or busy.
394 */
395 if (atomic_cmpxchg(&ev->value, EV_FREE, EV_BUSY) == EV_SET) {
396 return;
397 }
398 }
399 qemu_futex_wait(ev, EV_BUSY);
400 }
401 }
402
403 static pthread_key_t exit_key;
404
405 union NotifierThreadData {
406 void *ptr;
407 NotifierList list;
408 };
409 QEMU_BUILD_BUG_ON(sizeof(union NotifierThreadData) != sizeof(void *));
410
411 void qemu_thread_atexit_add(Notifier *notifier)
412 {
413 union NotifierThreadData ntd;
414 ntd.ptr = pthread_getspecific(exit_key);
415 notifier_list_add(&ntd.list, notifier);
416 pthread_setspecific(exit_key, ntd.ptr);
417 }
418
419 void qemu_thread_atexit_remove(Notifier *notifier)
420 {
421 union NotifierThreadData ntd;
422 ntd.ptr = pthread_getspecific(exit_key);
423 notifier_remove(notifier);
424 pthread_setspecific(exit_key, ntd.ptr);
425 }
426
427 static void qemu_thread_atexit_run(void *arg)
428 {
429 union NotifierThreadData ntd = { .ptr = arg };
430 notifier_list_notify(&ntd.list, NULL);
431 }
432
433 static void __attribute__((constructor)) qemu_thread_atexit_init(void)
434 {
435 pthread_key_create(&exit_key, qemu_thread_atexit_run);
436 }
437
438
439 /* Attempt to set the threads name; note that this is for debug, so
440 * we're not going to fail if we can't set it.
441 */
442 static void qemu_thread_set_name(QemuThread *thread, const char *name)
443 {
444 #ifdef CONFIG_PTHREAD_SETNAME_NP
445 pthread_setname_np(thread->thread, name);
446 #endif
447 }
448
449 void qemu_thread_create(QemuThread *thread, const char *name,
450 void *(*start_routine)(void*),
451 void *arg, int mode)
452 {
453 sigset_t set, oldset;
454 int err;
455 pthread_attr_t attr;
456
457 err = pthread_attr_init(&attr);
458 if (err) {
459 error_exit(err, __func__);
460 }
461
462 /* Leave signal handling to the iothread. */
463 sigfillset(&set);
464 pthread_sigmask(SIG_SETMASK, &set, &oldset);
465 err = pthread_create(&thread->thread, &attr, start_routine, arg);
466 if (err)
467 error_exit(err, __func__);
468
469 if (name_threads) {
470 qemu_thread_set_name(thread, name);
471 }
472
473 if (mode == QEMU_THREAD_DETACHED) {
474 err = pthread_detach(thread->thread);
475 if (err) {
476 error_exit(err, __func__);
477 }
478 }
479 pthread_sigmask(SIG_SETMASK, &oldset, NULL);
480
481 pthread_attr_destroy(&attr);
482 }
483
484 void qemu_thread_get_self(QemuThread *thread)
485 {
486 thread->thread = pthread_self();
487 }
488
489 bool qemu_thread_is_self(QemuThread *thread)
490 {
491 return pthread_equal(pthread_self(), thread->thread);
492 }
493
494 void qemu_thread_exit(void *retval)
495 {
496 pthread_exit(retval);
497 }
498
499 void *qemu_thread_join(QemuThread *thread)
500 {
501 int err;
502 void *ret;
503
504 err = pthread_join(thread->thread, &ret);
505 if (err) {
506 error_exit(err, __func__);
507 }
508 return ret;
509 }