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