mach/lock-intern.h

   1 /* Copyright (C) 1994-2021 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 Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _LOCK_INTERN_H
  19 #define _LOCK_INTERN_H
  20
  21 #include <sys/cdefs.h>
  22 #if defined __USE_EXTERN_INLINES && defined _LIBC
  23 # include <lowlevellock.h>
  24 #endif
  25
  26 #ifndef _EXTERN_INLINE
  27 #define _EXTERN_INLINE __extern_inline
  28 #endif
  29
  30 /* The type of a spin lock variable.  */
  31 typedef unsigned int __spin_lock_t;
  32
  33 /* Static initializer for spinlocks.  */
  34 #define __SPIN_LOCK_INITIALIZER   LLL_LOCK_INITIALIZER
  35
  36 /* Initialize LOCK.  */
  37
  38 extern void __spin_lock_init (__spin_lock_t *__lock);
  39
  40 #if defined __USE_EXTERN_INLINES && defined _LIBC
  41 _EXTERN_INLINE void
  42 __spin_lock_init (__spin_lock_t *__lock)
  43 {
  44   *__lock = __SPIN_LOCK_INITIALIZER;
  45 }
  46 #endif
  47
  48
  49 /* Lock LOCK, blocking if we can't get it.  */
  50 extern void __spin_lock_solid (__spin_lock_t *__lock);
  51
  52 /* Lock the spin lock LOCK.  */
  53
  54 extern void __spin_lock (__spin_lock_t *__lock);
  55
  56 #if defined __USE_EXTERN_INLINES && defined _LIBC
  57 _EXTERN_INLINE void
  58 __spin_lock (__spin_lock_t *__lock)
  59 {
  60   __lll_lock (__lock, 0);
  61 }
  62 #endif
  63
  64 /* Unlock LOCK.  */
  65 extern void __spin_unlock (__spin_lock_t *__lock);
  66
  67 #if defined __USE_EXTERN_INLINES && defined _LIBC
  68 _EXTERN_INLINE void
  69 __spin_unlock (__spin_lock_t *__lock)
  70 {
  71   __lll_unlock (__lock, 0);
  72 }
  73 #endif
  74
  75 /* Try to lock LOCK; return nonzero if we locked it, zero if another has.  */
  76 extern int __spin_try_lock (__spin_lock_t *__lock);
  77
  78 #if defined __USE_EXTERN_INLINES && defined _LIBC
  79 _EXTERN_INLINE int
  80 __spin_try_lock (__spin_lock_t *__lock)
  81 {
  82   return (__lll_trylock (__lock) == 0);
  83 }
  84 #endif
  85
  86 /* Return nonzero if LOCK is locked.  */
  87 extern int __spin_lock_locked (__spin_lock_t *__lock);
  88
  89 #if defined __USE_EXTERN_INLINES && defined _LIBC
  90 _EXTERN_INLINE int
  91 __spin_lock_locked (__spin_lock_t *__lock)
  92 {
  93   return (*(volatile __spin_lock_t *)__lock != 0);
  94 }
  95 #endif
  96 \f
  97 /* Name space-clean internal interface to mutex locks.  */
  98 struct mutex {
  99         __spin_lock_t __held;
 100         __spin_lock_t __lock;
 101         const char *__name;
 102         void *__head, *__tail;
 103         void *__holder;
 104 };
 105
 106 #define MUTEX_INITIALIZER { __SPIN_LOCK_INITIALIZER }
 107
 108 /* Initialize the newly allocated mutex lock LOCK for further use.  */
 109 extern void __mutex_init (void *__lock);
 110
 111 /* Lock the mutex lock LOCK.  */
 112
 113 extern void __mutex_lock (void *__lock);
 114
 115 #if defined __USE_EXTERN_INLINES && defined _LIBC
 116 _EXTERN_INLINE void
 117 __mutex_lock (void *__lock)
 118 {
 119   __spin_lock ((__spin_lock_t *)__lock);
 120 }
 121 #endif
 122
 123 /* Unlock the mutex lock LOCK.  */
 124
 125 extern void __mutex_unlock (void *__lock);
 126
 127 #if defined __USE_EXTERN_INLINES && defined _LIBC
 128 _EXTERN_INLINE void
 129 __mutex_unlock (void *__lock)
 130 {
 131   __spin_unlock ((__spin_lock_t *)__lock);
 132 }
 133 #endif
 134
 135
 136 extern int __mutex_trylock (void *__lock);
 137
 138 #if defined __USE_EXTERN_INLINES && defined _LIBC
 139 _EXTERN_INLINE int
 140 __mutex_trylock (void *__lock)
 141 {
 142   return (__spin_try_lock ((__spin_lock_t *)__lock));
 143 }
 144 #endif
 145
 146 #endif /* lock-intern.h */