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
  38 extern QemuMutexLockFunc qemu_mutex_lock_func;
  39 extern QemuMutexTrylockFunc qemu_mutex_trylock_func;
  40 extern QemuRecMutexLockFunc qemu_rec_mutex_lock_func;
  41 extern QemuRecMutexTrylockFunc qemu_rec_mutex_trylock_func;
  42 extern QemuCondWaitFunc qemu_cond_wait_func;
  43
  44 /* convenience macros to bypass the profiler */
  45 #define qemu_mutex_lock__raw(m)                         \
  46         qemu_mutex_lock_impl(m, __FILE__, __LINE__)
  47 #define qemu_mutex_trylock__raw(m)                      \
  48         qemu_mutex_trylock_impl(m, __FILE__, __LINE__)
  49
  50 #define qemu_mutex_lock(m) ({                                           \
  51             QemuMutexLockFunc _f = atomic_read(&qemu_mutex_lock_func);  \
  52             _f(m, __FILE__, __LINE__);                                  \
  53         })
  54
  55 #define qemu_mutex_trylock(m) ({                                        \
  56             QemuMutexTrylockFunc _f = atomic_read(&qemu_mutex_trylock_func); \
  57             _f(m, __FILE__, __LINE__);                                  \
  58         })
  59
  60 #define qemu_rec_mutex_lock(m) ({                                       \
  61             QemuRecMutexLockFunc _f = atomic_read(&qemu_rec_mutex_lock_func); \
  62             _f(m, __FILE__, __LINE__);                                  \
  63         })
  64
  65 #define qemu_rec_mutex_trylock(m) ({                            \
  66             QemuRecMutexTrylockFunc _f;                         \
  67             _f = atomic_read(&qemu_rec_mutex_trylock_func);     \
  68             _f(m, __FILE__, __LINE__);                          \
  69         })
  70
  71 #define qemu_cond_wait(c, m) ({                                         \
  72             QemuCondWaitFunc _f = atomic_read(&qemu_cond_wait_func);    \
  73             _f(c, m, __FILE__, __LINE__);                               \
  74         })
  75
  76 #define qemu_mutex_unlock(mutex) \
  77         qemu_mutex_unlock_impl(mutex, __FILE__, __LINE__)
  78
  79 static inline void (qemu_mutex_lock)(QemuMutex *mutex)
  80 {
  81     qemu_mutex_lock(mutex);
  82 }
  83
  84 static inline int (qemu_mutex_trylock)(QemuMutex *mutex)
  85 {
  86     return qemu_mutex_trylock(mutex);
  87 }
  88
  89 static inline void (qemu_mutex_unlock)(QemuMutex *mutex)
  90 {
  91     qemu_mutex_unlock(mutex);
  92 }
  93
  94 static inline void (qemu_rec_mutex_lock)(QemuRecMutex *mutex)
  95 {
  96     qemu_rec_mutex_lock(mutex);
  97 }
  98
  99 static inline int (qemu_rec_mutex_trylock)(QemuRecMutex *mutex)
 100 {
 101     return qemu_rec_mutex_trylock(mutex);
 102 }
 103
 104 /* Prototypes for other functions are in thread-posix.h/thread-win32.h.  */
 105 void qemu_rec_mutex_init(QemuRecMutex *mutex);
 106
 107 void qemu_cond_init(QemuCond *cond);
 108 void qemu_cond_destroy(QemuCond *cond);
 109
 110 /*
 111  * IMPORTANT: The implementation does not guarantee that pthread_cond_signal
 112  * and pthread_cond_broadcast can be called except while the same mutex is
 113  * held as in the corresponding pthread_cond_wait calls!
 114  */
 115 void qemu_cond_signal(QemuCond *cond);
 116 void qemu_cond_broadcast(QemuCond *cond);
 117 void qemu_cond_wait_impl(QemuCond *cond, QemuMutex *mutex,
 118                          const char *file, const int line);
 119
 120 static inline void (qemu_cond_wait)(QemuCond *cond, QemuMutex *mutex)
 121 {
 122     qemu_cond_wait(cond, mutex);
 123 }
 124
 125 void qemu_sem_init(QemuSemaphore *sem, int init);
 126 void qemu_sem_post(QemuSemaphore *sem);
 127 void qemu_sem_wait(QemuSemaphore *sem);
 128 int qemu_sem_timedwait(QemuSemaphore *sem, int ms);
 129 void qemu_sem_destroy(QemuSemaphore *sem);
 130
 131 void qemu_event_init(QemuEvent *ev, bool init);
 132 void qemu_event_set(QemuEvent *ev);
 133 void qemu_event_reset(QemuEvent *ev);
 134 void qemu_event_wait(QemuEvent *ev);
 135 void qemu_event_destroy(QemuEvent *ev);
 136
 137 void qemu_thread_create(QemuThread *thread, const char *name,
 138                         void *(*start_routine)(void *),
 139                         void *arg, int mode);
 140 void *qemu_thread_join(QemuThread *thread);
 141 void qemu_thread_get_self(QemuThread *thread);
 142 bool qemu_thread_is_self(QemuThread *thread);
 143 void qemu_thread_exit(void *retval);
 144 void qemu_thread_naming(bool enable);
 145
 146 struct Notifier;
 147 void qemu_thread_atexit_add(struct Notifier *notifier);
 148 void qemu_thread_atexit_remove(struct Notifier *notifier);
 149
 150 struct QemuSpin {
 151     int value;
 152 };
 153
 154 static inline void qemu_spin_init(QemuSpin *spin)
 155 {
 156     __sync_lock_release(&spin->value);
 157 }
 158
 159 static inline void qemu_spin_lock(QemuSpin *spin)
 160 {
 161     while (unlikely(__sync_lock_test_and_set(&spin->value, true))) {
 162         while (atomic_read(&spin->value)) {
 163             cpu_relax();
 164         }
 165     }
 166 }
 167
 168 static inline bool qemu_spin_trylock(QemuSpin *spin)
 169 {
 170     return __sync_lock_test_and_set(&spin->value, true);
 171 }
 172
 173 static inline bool qemu_spin_locked(QemuSpin *spin)
 174 {
 175     return atomic_read(&spin->value);
 176 }
 177
 178 static inline void qemu_spin_unlock(QemuSpin *spin)
 179 {
 180     __sync_lock_release(&spin->value);
 181 }
 182
 183 struct QemuLockCnt {
 184 #ifndef CONFIG_LINUX
 185     QemuMutex mutex;
 186 #endif
 187     unsigned count;
 188 };
 189
 190 /**
 191  * qemu_lockcnt_init: initialize a QemuLockcnt
 192  * @lockcnt: the lockcnt to initialize
 193  *
 194  * Initialize lockcnt's counter to zero and prepare its mutex
 195  * for usage.
 196  */
 197 void qemu_lockcnt_init(QemuLockCnt *lockcnt);
 198
 199 /**
 200  * qemu_lockcnt_destroy: destroy a QemuLockcnt
 201  * @lockcnt: the lockcnt to destruct
 202  *
 203  * Destroy lockcnt's mutex.
 204  */
 205 void qemu_lockcnt_destroy(QemuLockCnt *lockcnt);
 206
 207 /**
 208  * qemu_lockcnt_inc: increment a QemuLockCnt's counter
 209  * @lockcnt: the lockcnt to operate on
 210  *
 211  * If the lockcnt's count is zero, wait for critical sections
 212  * to finish and increment lockcnt's count to 1.  If the count
 213  * is not zero, just increment it.
 214  *
 215  * Because this function can wait on the mutex, it must not be
 216  * called while the lockcnt's mutex is held by the current thread.
 217  * For the same reason, qemu_lockcnt_inc can also contribute to
 218  * AB-BA deadlocks.  This is a sample deadlock scenario:
 219  *
 220  *            thread 1                      thread 2
 221  *            -------------------------------------------------------
 222  *            qemu_lockcnt_lock(&lc1);
 223  *                                          qemu_lockcnt_lock(&lc2);
 224  *            qemu_lockcnt_inc(&lc2);
 225  *                                          qemu_lockcnt_inc(&lc1);
 226  */
 227 void qemu_lockcnt_inc(QemuLockCnt *lockcnt);
 228
 229 /**
 230  * qemu_lockcnt_dec: decrement a QemuLockCnt's counter
 231  * @lockcnt: the lockcnt to operate on
 232  */
 233 void qemu_lockcnt_dec(QemuLockCnt *lockcnt);
 234
 235 /**
 236  * qemu_lockcnt_dec_and_lock: decrement a QemuLockCnt's counter and
 237  * possibly lock it.
 238  * @lockcnt: the lockcnt to operate on
 239  *
 240  * Decrement lockcnt's count.  If the new count is zero, lock
 241  * the mutex and return true.  Otherwise, return false.
 242  */
 243 bool qemu_lockcnt_dec_and_lock(QemuLockCnt *lockcnt);
 244
 245 /**
 246  * qemu_lockcnt_dec_if_lock: possibly decrement a QemuLockCnt's counter and
 247  * lock it.
 248  * @lockcnt: the lockcnt to operate on
 249  *
 250  * If the count is 1, decrement the count to zero, lock
 251  * the mutex and return true.  Otherwise, return false.
 252  */
 253 bool qemu_lockcnt_dec_if_lock(QemuLockCnt *lockcnt);
 254
 255 /**
 256  * qemu_lockcnt_lock: lock a QemuLockCnt's mutex.
 257  * @lockcnt: the lockcnt to operate on
 258  *
 259  * Remember that concurrent visits are not blocked unless the count is
 260  * also zero.  You can use qemu_lockcnt_count to check for this inside a
 261  * critical section.
 262  */
 263 void qemu_lockcnt_lock(QemuLockCnt *lockcnt);
 264
 265 /**
 266  * qemu_lockcnt_unlock: release a QemuLockCnt's mutex.
 267  * @lockcnt: the lockcnt to operate on.
 268  */
 269 void qemu_lockcnt_unlock(QemuLockCnt *lockcnt);
 270
 271 /**
 272  * qemu_lockcnt_inc_and_unlock: combined unlock/increment on a QemuLockCnt.
 273  * @lockcnt: the lockcnt to operate on.
 274  *
 275  * This is the same as
 276  *
 277  *     qemu_lockcnt_unlock(lockcnt);
 278  *     qemu_lockcnt_inc(lockcnt);
 279  *
 280  * but more efficient.
 281  */
 282 void qemu_lockcnt_inc_and_unlock(QemuLockCnt *lockcnt);
 283
 284 /**
 285  * qemu_lockcnt_count: query a LockCnt's count.
 286  * @lockcnt: the lockcnt to query.
 287  *
 288  * Note that the count can change at any time.  Still, while the
 289  * lockcnt is locked, one can usefully check whether the count
 290  * is non-zero.
 291  */
 292 unsigned qemu_lockcnt_count(QemuLockCnt *lockcnt);
 293
 294 #endif