nptl/sysdeps/unix/sysv/linux/alpha/lowlevellock.h

   1 /* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Libr    \ary; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _LOWLEVELLOCK_H
  20 #define _LOWLEVELLOCK_H 1
  21
  22 #include <time.h>
  23 #include <sys/param.h>
  24 #include <bits/pthreadtypes.h>
  25 #include <atomic.h>
  26 #include <sysdep.h>
  27
  28
  29 #define __NR_futex              394
  30 #define FUTEX_WAIT              0
  31 #define FUTEX_WAKE              1
  32 #define FUTEX_REQUEUE           3
  33 #define FUTEX_CMP_REQUEUE       4
  34
  35 /* Initializer for compatibility lock.  */
  36 #define LLL_MUTEX_LOCK_INITIALIZER (0)
  37
  38 #define lll_futex_wait(futexp, val) \
  39   ({                                                                          \
  40     INTERNAL_SYSCALL_DECL (__err);                                            \
  41     long int __ret;                                                           \
  42     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  43                               (futexp), FUTEX_WAIT, (val), 0);                \
  44     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret;                  \
  45   })
  46
  47 #define lll_futex_timed_wait(futexp, val, timespec) \
  48   ({                                                                          \
  49     INTERNAL_SYSCALL_DECL (__err);                                            \
  50     long int __ret;                                                           \
  51     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  52                               (futexp), FUTEX_WAIT, (val), (timespec));       \
  53     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret;                  \
  54   })
  55
  56 #define lll_futex_wake(futexp, nr) \
  57   ({                                                                          \
  58     INTERNAL_SYSCALL_DECL (__err);                                            \
  59     long int __ret;                                                           \
  60     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  61                               (futexp), FUTEX_WAKE, (nr), 0);                 \
  62     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret;                  \
  63   })
  64
  65 /* Returns non-zero if error happened, zero if success.  */
  66 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val) \
  67   ({                                                                          \
  68     INTERNAL_SYSCALL_DECL (__err);                                            \
  69     long int __ret;                                                           \
  70     __ret = INTERNAL_SYSCALL (futex, __err, 6,                                \
  71                               (futexp), FUTEX_CMP_REQUEUE, (nr_wake),         \
  72                               (nr_move), (mutex), (val));                     \
  73     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
  74   })
  75
  76
  77 static inline int __attribute__((always_inline))
  78 __lll_mutex_trylock(int *futex)
  79 {
  80   return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0;
  81 }
  82 #define lll_mutex_trylock(lock) __lll_mutex_trylock (&(lock))
  83
  84
  85 static inline int __attribute__((always_inline))
  86 __lll_mutex_cond_trylock(int *futex)
  87 {
  88   return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0;
  89 }
  90 #define lll_mutex_cond_trylock(lock)    __lll_mutex_cond_trylock (&(lock))
  91
  92
  93 extern void __lll_lock_wait (int *futex) attribute_hidden;
  94
  95 static inline void __attribute__((always_inline))
  96 __lll_mutex_lock(int *futex)
  97 {
  98   if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
  99     __lll_lock_wait (futex);
 100 }
 101 #define lll_mutex_lock(futex) __lll_mutex_lock (&(futex))
 102
 103
 104 static inline void __attribute__ ((always_inline))
 105 __lll_mutex_cond_lock (int *futex)
 106 {
 107   if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
 108     __lll_lock_wait (futex);
 109 }
 110 #define lll_mutex_cond_lock(futex) __lll_mutex_cond_lock (&(futex))
 111
 112
 113 extern int __lll_timedlock_wait (int *futex, const struct timespec *)
 114         attribute_hidden;
 115
 116 static inline int __attribute__ ((always_inline))
 117 __lll_mutex_timedlock (int *futex, const struct timespec *abstime)
 118 {
 119   int result = 0;
 120   if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
 121     result = __lll_timedlock_wait (futex, abstime);
 122   return result;
 123 }
 124 #define lll_mutex_timedlock(futex, abstime) \
 125   __lll_mutex_timedlock (&(futex), abstime)
 126
 127
 128 static inline void __attribute__ ((always_inline))
 129 __lll_mutex_unlock (int *futex)
 130 {
 131   int val = atomic_exchange_rel (futex, 0);
 132   if (__builtin_expect (val > 1, 0))
 133     lll_futex_wake (futex, 1);
 134 }
 135 #define lll_mutex_unlock(futex) __lll_mutex_unlock(&(futex))
 136
 137
 138 static inline void __attribute__ ((always_inline))
 139 __lll_mutex_unlock_force (int *futex)
 140 {
 141   (void) atomic_exchange_rel (futex, 0);
 142   lll_futex_wake (futex, 1);
 143 }
 144 #define lll_mutex_unlock_force(futex) __lll_mutex_unlock_force(&(futex))
 145
 146
 147 #define lll_mutex_islocked(futex) \
 148   (futex != 0)
 149
 150
 151 /* Our internal lock implementation is identical to the binary-compatible
 152    mutex implementation. */
 153
 154 /* Type for lock object.  */
 155 typedef int lll_lock_t;
 156
 157 /* Initializers for lock.  */
 158 #define LLL_LOCK_INITIALIZER            (0)
 159 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 160
 161 extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
 162
 163 /* The states of a lock are:
 164     0  -  untaken
 165     1  -  taken by one user
 166    >1  -  taken by more users */
 167
 168 #define lll_trylock(lock)       lll_mutex_trylock (lock)
 169 #define lll_lock(lock)          lll_mutex_lock (lock)
 170 #define lll_unlock(lock)        lll_mutex_unlock (lock)
 171 #define lll_islocked(lock)      lll_mutex_islocked (lock)
 172
 173 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
 174    wakeup when the clone terminates.  The memory location contains the
 175    thread ID while the clone is running and is reset to zero
 176    afterwards.  */
 177 #define lll_wait_tid(tid) \
 178   do {                                  \
 179     __typeof (tid) __tid;               \
 180     while ((__tid = (tid)) != 0)        \
 181       lll_futex_wait (&(tid), __tid);   \
 182   } while (0)
 183
 184 extern int __lll_timedwait_tid (int *, const struct timespec *)
 185      attribute_hidden;
 186
 187 #define lll_timedwait_tid(tid, abstime) \
 188   ({                                                    \
 189     int __res = 0;                                      \
 190     if ((tid) != 0)                                     \
 191       __res = __lll_timedwait_tid (&(tid), (abstime));  \
 192     __res;                                              \
 193   })
 194
 195
 196 /* Conditional variable handling.  */
 197
 198 extern void __lll_cond_wait (pthread_cond_t *cond)
 199      attribute_hidden;
 200 extern int __lll_cond_timedwait (pthread_cond_t *cond,
 201                                  const struct timespec *abstime)
 202      attribute_hidden;
 203 extern void __lll_cond_wake (pthread_cond_t *cond)
 204      attribute_hidden;
 205 extern void __lll_cond_broadcast (pthread_cond_t *cond)
 206      attribute_hidden;
 207
 208 #define lll_cond_wait(cond) \
 209   __lll_cond_wait (cond)
 210 #define lll_cond_timedwait(cond, abstime) \
 211   __lll_cond_timedwait (cond, abstime)
 212 #define lll_cond_wake(cond) \
 213   __lll_cond_wake (cond)
 214 #define lll_cond_broadcast(cond) \
 215   __lll_cond_broadcast (cond)
 216
 217 #endif  /* lowlevellock.h */