sysdeps/unix/sysv/linux/sparc/lowlevellock.h

   1 /* Copyright (C) 2003-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  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 <kernel-features.h>
  27
  28 #include <lowlevellock-futex.h>
  29
  30 static inline int
  31 __attribute__ ((always_inline))
  32 __lll_trylock (int *futex)
  33 {
  34   return atomic_compare_and_exchange_val_24_acq (futex, 1, 0) != 0;
  35 }
  36 #define lll_trylock(futex) __lll_trylock (&(futex))
  37
  38 static inline int
  39 __attribute__ ((always_inline))
  40 __lll_cond_trylock (int *futex)
  41 {
  42   return atomic_compare_and_exchange_val_24_acq (futex, 2, 0) != 0;
  43 }
  44 #define lll_cond_trylock(futex) __lll_cond_trylock (&(futex))
  45
  46
  47 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
  48 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
  49
  50 static inline void
  51 __attribute__ ((always_inline))
  52 __lll_lock (int *futex, int private)
  53 {
  54   int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);
  55
  56   if (__glibc_unlikely (val != 0))
  57     {
  58       if (__builtin_constant_p (private) && private == LLL_PRIVATE)
  59         __lll_lock_wait_private (futex);
  60       else
  61         __lll_lock_wait (futex, private);
  62     }
  63 }
  64 #define lll_lock(futex, private) __lll_lock (&(futex), private)
  65
  66 static inline void
  67 __attribute__ ((always_inline))
  68 __lll_cond_lock (int *futex, int private)
  69 {
  70   int val = atomic_compare_and_exchange_val_24_acq (futex, 2, 0);
  71
  72   if (__glibc_unlikely (val != 0))
  73     __lll_lock_wait (futex, private);
  74 }
  75 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
  76
  77
  78 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
  79                                  int private) attribute_hidden;
  80
  81 static inline int
  82 __attribute__ ((always_inline))
  83 __lll_timedlock (int *futex, const struct timespec *abstime, int private)
  84 {
  85   int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);
  86   int result = 0;
  87
  88   if (__glibc_unlikely (val != 0))
  89     result = __lll_timedlock_wait (futex, abstime, private);
  90   return result;
  91 }
  92 #define lll_timedlock(futex, abstime, private) \
  93   __lll_timedlock (&(futex), abstime, private)
  94
  95 #define lll_unlock(lock, private) \
  96   ((void) ({                                                                  \
  97     int *__futex = &(lock);                                                   \
  98     int __private = (private);                                                \
  99     int __val = atomic_exchange_24_rel (__futex, 0);                          \
 100     if (__glibc_unlikely (__val > 1))                                         \
 101       lll_futex_wake (__futex, 1, __private);                                 \
 102   }))
 103
 104 #define lll_islocked(futex) \
 105   (futex != 0)
 106
 107 /* Initializers for lock.  */
 108 #define LLL_LOCK_INITIALIZER            (0)
 109 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 110
 111 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
 112    wakeup when the clone terminates.  The memory location contains the
 113    thread ID while the clone is running and is reset to zero
 114    afterwards.  */
 115 #define lll_wait_tid(tid) \
 116   do                                                    \
 117     {                                                   \
 118       __typeof (tid) __tid;                             \
 119       while ((__tid = (tid)) != 0)                      \
 120         lll_futex_wait (&(tid), __tid, LLL_SHARED);     \
 121     }                                                   \
 122   while (0)
 123
 124 extern int __lll_timedwait_tid (int *, const struct timespec *)
 125      attribute_hidden;
 126
 127 #define lll_timedwait_tid(tid, abstime) \
 128   ({                                                    \
 129     int __res = 0;                                      \
 130     if ((tid) != 0)                                     \
 131       __res = __lll_timedwait_tid (&(tid), (abstime));  \
 132     __res;                                              \
 133   })
 134
 135 #endif  /* lowlevellock.h */