include/qemu/thread.h

   1 #ifndef QEMU_THREAD_H
   2 #define QEMU_THREAD_H
   3
   4 #include "qemu/processor.h"
   5 #include "qemu/atomic.h"
   6
   7 typedef struct QemuCond QemuCond;
   8 typedef struct QemuSemaphore QemuSemaphore;
   9 typedef struct QemuEvent QemuEvent;
  10 typedef struct QemuLockCnt QemuLockCnt;
  11 typedef struct QemuThread QemuThread;
  12
  13 #ifdef _WIN32
  14 #include "qemu/thread-win32.h"
  15 #else
  16 #include "qemu/thread-posix.h"
  17 #endif
  18
  19 /* include QSP header once QemuMutex, QemuCond etc. are defined */
  20 #include "qemu/qsp.h"
  21
  22 #define QEMU_THREAD_JOINABLE 0
  23 #define QEMU_THREAD_DETACHED 1
  24
  25 void qemu_mutex_init(QemuMutex *mutex);
  26 void qemu_mutex_destroy(QemuMutex *mutex);
  27 int qemu_mutex_trylock_impl(QemuMutex *mutex, const char *file, const int line);
  28 void qemu_mutex_lock_impl(QemuMutex *mutex, const char *file, const int line);
  29 void qemu_mutex_unlock_impl(QemuMutex *mutex, const char *file, const int line);
  30
  31 typedef void (*QemuMutexLockFunc)(QemuMutex *m, const char *f, int l);
  32 typedef int (*QemuMutexTrylockFunc)(QemuMutex *m, const char *f, int l);
  33 typedef void (*QemuRecMutexLockFunc)(QemuRecMutex *m, const char *f, int l);
  34 typedef int (*QemuRecMutexTrylockFunc)(QemuRecMutex *m, const char *f, int l);
  35 typedef void (*QemuCondWaitFunc)(QemuCond *c, QemuMutex *m, const char *f,
  36                                  int l);
  37 typedef bool (*QemuCondTimedWaitFunc)(QemuCond *c, QemuMutex *m, int ms,
  38                                       const char *f, int l);
  39
  40 extern QemuMutexLockFunc qemu_bql_mutex_lock_func;
  41 extern QemuMutexLockFunc qemu_mutex_lock_func;
  42 extern QemuMutexTrylockFunc qemu_mutex_trylock_func;
  43 extern QemuRecMutexLockFunc qemu_rec_mutex_lock_func;
  44 extern QemuRecMutexTrylockFunc qemu_rec_mutex_trylock_func;
  45 extern QemuCondWaitFunc qemu_cond_wait_func;
  46 extern QemuCondTimedWaitFunc qemu_cond_timedwait_func;
  47
  48 /* convenience macros to bypass the profiler */
  49 #define qemu_mutex_lock__raw(m)                         \
  50         qemu_mutex_lock_impl(m, __FILE__, __LINE__)
  51 #define qemu_mutex_trylock__raw(m)                      \
  52         qemu_mutex_trylock_impl(m, __FILE__, __LINE__)
  53
  54 #ifdef __COVERITY__
  55 /*
  56  * Coverity is severely confused by the indirect function calls,
  57  * hide them.
  58  */
  59 #define qemu_mutex_lock(m)                                              \
  60             qemu_mutex_lock_impl(m, __FILE__, __LINE__);
  61 #define qemu_mutex_trylock(m)                                           \
  62             qemu_mutex_trylock_impl(m, __FILE__, __LINE__);
  63 #define qemu_rec_mutex_lock(m)                                          \
  64             qemu_rec_mutex_lock_impl(m, __FILE__, __LINE__);
  65 #define qemu_rec_mutex_trylock(m)                                       \
  66             qemu_rec_mutex_trylock_impl(m, __FILE__, __LINE__);
  67 #define qemu_cond_wait(c, m)                                            \
  68             qemu_cond_wait_impl(c, m, __FILE__, __LINE__);
  69 #define qemu_cond_timedwait(c, m, ms)                                   \
  70             qemu_cond_wait_impl(c, m, ms, __FILE__, __LINE__);
  71 #else
  72 #define qemu_mutex_lock(m) ({                                           \
  73             QemuMutexLockFunc _f = atomic_read(&qemu_mutex_lock_func);  \
  74             _f(m, __FILE__, __LINE__);                                  \
  75         })
  76
  77 #define qemu_mutex_trylock(m) ({                                        \
  78             QemuMutexTrylockFunc _f = atomic_read(&qemu_mutex_trylock_func); \
  79             _f(m, __FILE__, __LINE__);                                  \
  80         })
  81
  82 #define qemu_rec_mutex_lock(m) ({                                       \
  83             QemuRecMutexLockFunc _f = atomic_read(&qemu_rec_mutex_lock_func); \
  84             _f(m, __FILE__, __LINE__);                                  \
  85         })
  86
  87 #define qemu_rec_mutex_trylock(m) ({                            \
  88             QemuRecMutexTrylockFunc _f;                         \
  89             _f = atomic_read(&qemu_rec_mutex_trylock_func);     \
  90             _f(m, __FILE__, __LINE__);                          \
  91         })
  92
  93 #define qemu_cond_wait(c, m) ({                                         \
  94             QemuCondWaitFunc _f = atomic_read(&qemu_cond_wait_func);    \
  95             _f(c, m, __FILE__, __LINE__);                               \
  96         })
  97
  98 #define qemu_cond_timedwait(c, m, ms) ({                                       \
  99             QemuCondTimedWaitFunc _f = atomic_read(&qemu_cond_timedwait_func); \
 100             _f(c, m, ms, __FILE__, __LINE__);                                  \
 101         })
 102 #endif
 103
 104 #define qemu_mutex_unlock(mutex) \
 105         qemu_mutex_unlock_impl(mutex, __FILE__, __LINE__)
 106
 107 static inline void (qemu_mutex_lock)(QemuMutex *mutex)
 108 {
 109     qemu_mutex_lock(mutex);
 110 }
 111
 112 static inline int (qemu_mutex_trylock)(QemuMutex *mutex)
 113 {
 114     return qemu_mutex_trylock(mutex);
 115 }
 116
 117 static inline void (qemu_mutex_unlock)(QemuMutex *mutex)
 118 {
 119     qemu_mutex_unlock(mutex);
 120 }
 121
 122 static inline void (qemu_rec_mutex_lock)(QemuRecMutex *mutex)
 123 {
 124     qemu_rec_mutex_lock(mutex);
 125 }
 126
 127 static inline int (qemu_rec_mutex_trylock)(QemuRecMutex *mutex)
 128 {
 129     return qemu_rec_mutex_trylock(mutex);
 130 }
 131
 132 /* Prototypes for other functions are in thread-posix.h/thread-win32.h.  */
 133 void qemu_rec_mutex_init(QemuRecMutex *mutex);
 134
 135 void qemu_cond_init(QemuCond *cond);
 136 void qemu_cond_destroy(QemuCond *cond);
 137
 138 /*
 139  * IMPORTANT: The implementation does not guarantee that pthread_cond_signal
 140  * and pthread_cond_broadcast can be called except while the same mutex is
 141  * held as in the corresponding pthread_cond_wait calls!
 142  */
 143 void qemu_cond_signal(QemuCond *cond);
 144 void qemu_cond_broadcast(QemuCond *cond);
 145 void qemu_cond_wait_impl(QemuCond *cond, QemuMutex *mutex,
 146                          const char *file, const int line);
 147 bool qemu_cond_timedwait_impl(QemuCond *cond, QemuMutex *mutex, int ms,
 148                               const char *file, const int line);
 149
 150 static inline void (qemu_cond_wait)(QemuCond *cond, QemuMutex *mutex)
 151 {
 152     qemu_cond_wait(cond, mutex);
 153 }
 154
 155 /* Returns true if timeout has not expired, and false otherwise */
 156 static inline bool (qemu_cond_timedwait)(QemuCond *cond, QemuMutex *mutex,
 157                                          int ms)
 158 {
 159     return qemu_cond_timedwait(cond, mutex, ms);
 160 }
 161
 162 void qemu_sem_init(QemuSemaphore *sem, int init);
 163 void qemu_sem_post(QemuSemaphore *sem);
 164 void qemu_sem_wait(QemuSemaphore *sem);
 165 int qemu_sem_timedwait(QemuSemaphore *sem, int ms);
 166 void qemu_sem_destroy(QemuSemaphore *sem);
 167
 168 void qemu_event_init(QemuEvent *ev, bool init);
 169 void qemu_event_set(QemuEvent *ev);
 170 void qemu_event_reset(QemuEvent *ev);
 171 void qemu_event_wait(QemuEvent *ev);
 172 void qemu_event_destroy(QemuEvent *ev);
 173
 174 void qemu_thread_create(QemuThread *thread, const char *name,
 175                         void *(*start_routine)(void *),
 176                         void *arg, int mode);
 177 void *qemu_thread_join(QemuThread *thread);
 178 void qemu_thread_get_self(QemuThread *thread);
 179 bool qemu_thread_is_self(QemuThread *thread);
 180 void qemu_thread_exit(void *retval);
 181 void qemu_thread_naming(bool enable);
 182
 183 struct Notifier;
 184 /**
 185  * qemu_thread_atexit_add:
 186  * @notifier: Notifier to add
 187  *
 188  * Add the specified notifier to a list which will be run via
 189  * notifier_list_notify() when this thread exits (either by calling
 190  * qemu_thread_exit() or by returning from its start_routine).
 191  * The usual usage is that the caller passes a Notifier which is
 192  * a per-thread variable; it can then use the callback to free
 193  * other per-thread data.
 194  *
 195  * If the thread exits as part of the entire process exiting,
 196  * it is unspecified whether notifiers are called or not.
 197  */
 198 void qemu_thread_atexit_add(struct Notifier *notifier);
 199 /**
 200  * qemu_thread_atexit_remove:
 201  * @notifier: Notifier to remove
 202  *
 203  * Remove the specified notifier from the thread-exit notification
 204  * list. It is not valid to try to remove a notifier which is not
 205  * on the list.
 206  */
 207 void qemu_thread_atexit_remove(struct Notifier *notifier);
 208
 209 struct QemuSpin {
 210     int value;
 211 };
 212
 213 static inline void qemu_spin_init(QemuSpin *spin)
 214 {
 215     __sync_lock_release(&spin->value);
 216 }
 217
 218 static inline void qemu_spin_lock(QemuSpin *spin)
 219 {
 220     while (unlikely(__sync_lock_test_and_set(&spin->value, true))) {
 221         while (atomic_read(&spin->value)) {
 222             cpu_relax();
 223         }
 224     }
 225 }
 226
 227 static inline bool qemu_spin_trylock(QemuSpin *spin)
 228 {
 229     return __sync_lock_test_and_set(&spin->value, true);
 230 }
 231
 232 static inline bool qemu_spin_locked(QemuSpin *spin)
 233 {
 234     return atomic_read(&spin->value);
 235 }
 236
 237 static inline void qemu_spin_unlock(QemuSpin *spin)
 238 {
 239     __sync_lock_release(&spin->value);
 240 }
 241
 242 struct QemuLockCnt {
 243 #ifndef CONFIG_LINUX
 244     QemuMutex mutex;
 245 #endif
 246     unsigned count;
 247 };
 248
 249 /**
 250  * qemu_lockcnt_init: initialize a QemuLockcnt
 251  * @lockcnt: the lockcnt to initialize
 252  *
 253  * Initialize lockcnt's counter to zero and prepare its mutex
 254  * for usage.
 255  */
 256 void qemu_lockcnt_init(QemuLockCnt *lockcnt);
 257
 258 /**
 259  * qemu_lockcnt_destroy: destroy a QemuLockcnt
 260  * @lockcnt: the lockcnt to destruct
 261  *
 262  * Destroy lockcnt's mutex.
 263  */
 264 void qemu_lockcnt_destroy(QemuLockCnt *lockcnt);
 265
 266 /**
 267  * qemu_lockcnt_inc: increment a QemuLockCnt's counter
 268  * @lockcnt: the lockcnt to operate on
 269  *
 270  * If the lockcnt's count is zero, wait for critical sections
 271  * to finish and increment lockcnt's count to 1.  If the count
 272  * is not zero, just increment it.
 273  *
 274  * Because this function can wait on the mutex, it must not be
 275  * called while the lockcnt's mutex is held by the current thread.
 276  * For the same reason, qemu_lockcnt_inc can also contribute to
 277  * AB-BA deadlocks.  This is a sample deadlock scenario:
 278  *
 279  *            thread 1                      thread 2
 280  *            -------------------------------------------------------
 281  *            qemu_lockcnt_lock(&lc1);
 282  *                                          qemu_lockcnt_lock(&lc2);
 283  *            qemu_lockcnt_inc(&lc2);
 284  *                                          qemu_lockcnt_inc(&lc1);
 285  */
 286 void qemu_lockcnt_inc(QemuLockCnt *lockcnt);
 287
 288 /**
 289  * qemu_lockcnt_dec: decrement a QemuLockCnt's counter
 290  * @lockcnt: the lockcnt to operate on
 291  */
 292 void qemu_lockcnt_dec(QemuLockCnt *lockcnt);
 293
 294 /**
 295  * qemu_lockcnt_dec_and_lock: decrement a QemuLockCnt's counter and
 296  * possibly lock it.
 297  * @lockcnt: the lockcnt to operate on
 298  *
 299  * Decrement lockcnt's count.  If the new count is zero, lock
 300  * the mutex and return true.  Otherwise, return false.
 301  */
 302 bool qemu_lockcnt_dec_and_lock(QemuLockCnt *lockcnt);
 303
 304 /**
 305  * qemu_lockcnt_dec_if_lock: possibly decrement a QemuLockCnt's counter and
 306  * lock it.
 307  * @lockcnt: the lockcnt to operate on
 308  *
 309  * If the count is 1, decrement the count to zero, lock
 310  * the mutex and return true.  Otherwise, return false.
 311  */
 312 bool qemu_lockcnt_dec_if_lock(QemuLockCnt *lockcnt);
 313
 314 /**
 315  * qemu_lockcnt_lock: lock a QemuLockCnt's mutex.
 316  * @lockcnt: the lockcnt to operate on
 317  *
 318  * Remember that concurrent visits are not blocked unless the count is
 319  * also zero.  You can use qemu_lockcnt_count to check for this inside a
 320  * critical section.
 321  */
 322 void qemu_lockcnt_lock(QemuLockCnt *lockcnt);
 323
 324 /**
 325  * qemu_lockcnt_unlock: release a QemuLockCnt's mutex.
 326  * @lockcnt: the lockcnt to operate on.
 327  */
 328 void qemu_lockcnt_unlock(QemuLockCnt *lockcnt);
 329
 330 /**
 331  * qemu_lockcnt_inc_and_unlock: combined unlock/increment on a QemuLockCnt.
 332  * @lockcnt: the lockcnt to operate on.
 333  *
 334  * This is the same as
 335  *
 336  *     qemu_lockcnt_unlock(lockcnt);
 337  *     qemu_lockcnt_inc(lockcnt);
 338  *
 339  * but more efficient.
 340  */
 341 void qemu_lockcnt_inc_and_unlock(QemuLockCnt *lockcnt);
 342
 343 /**
 344  * qemu_lockcnt_count: query a LockCnt's count.
 345  * @lockcnt: the lockcnt to query.
 346  *
 347  * Note that the count can change at any time.  Still, while the
 348  * lockcnt is locked, one can usefully check whether the count
 349  * is non-zero.
 350  */
 351 unsigned qemu_lockcnt_count(QemuLockCnt *lockcnt);
 352
 353 #endif