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

   1 /* Copyright (C) 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Paul Mackerras <paulus@au.ibm.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 Libr    \ary; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _LOWLEVELLOCK_H
  21 #define _LOWLEVELLOCK_H 1
  22
  23 #include <time.h>
  24 #include <sys/param.h>
  25 #include <bits/pthreadtypes.h>
  26 #include <atomic.h>
  27
  28
  29 #define __NR_futex              221
  30 #define FUTEX_WAIT              0
  31 #define FUTEX_WAKE              1
  32
  33 /* Initializer for compatibility lock.  */
  34 #define LLL_MUTEX_LOCK_INITIALIZER (0)
  35
  36 #define lll_futex_wait(futexp, val) \
  37   ({                                                                          \
  38     INTERNAL_SYSCALL_DECL (__err);                                            \
  39     long int __ret;                                                           \
  40                                                                               \
  41     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  42                               (futexp), FUTEX_WAIT, (val), 0);                \
  43     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0;                       \
  44   })
  45
  46 #define lll_futex_timed_wait(futexp, val, timespec) \
  47   ({                                                                          \
  48     INTERNAL_SYSCALL_DECL (__err);                                            \
  49     long int __ret;                                                           \
  50                                                                               \
  51     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  52                               (futexp), FUTEX_WAIT, (val), (timespec));       \
  53     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0;                       \
  54   })
  55
  56 #define lll_futex_wake(futexp, nr) \
  57   ({                                                                          \
  58     INTERNAL_SYSCALL_DECL (__err);                                            \
  59     long int __ret;                                                           \
  60                                                                               \
  61     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  62                               (futexp), FUTEX_WAKE, (nr), 0);                 \
  63     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0;                       \
  64   })
  65
  66 #ifdef UP
  67 # define __lll_acq_instr        ""
  68 # define __lll_rel_instr        ""
  69 #else
  70 # define __lll_acq_instr        "isync"
  71 # define __lll_rel_instr        "sync"
  72 #endif
  73
  74 /* Set *futex to 1 if it is 0, atomically.  Returns the old value */
  75 #define __lll_trylock(futex) \
  76   ({ int __val;                                                               \
  77      __asm __volatile ("1:      lwarx   %0,0,%2\n"                            \
  78                        "        cmpwi   0,%0,0\n"                             \
  79                        "        bne     2f\n"                                 \
  80                        "        stwcx.  %3,0,%2\n"                            \
  81                        "        bne-    1b\n"                                 \
  82                        "2:      " __lll_acq_instr                             \
  83                        : "=&r" (__val), "=m" (*futex)                         \
  84                        : "r" (futex), "r" (1), "1" (*futex)                   \
  85                        : "cr0", "memory");                                    \
  86      __val;                                                                   \
  87   })
  88
  89 #define lll_mutex_trylock(lock) __lll_trylock (&(lock))
  90
  91
  92 extern void __lll_lock_wait (int *futex, int val) attribute_hidden;
  93
  94 #define lll_mutex_lock(lock) \
  95   (void) ({                                                                   \
  96     int *__futex = &(lock);                                                   \
  97     int __val = atomic_exchange_and_add (__futex, 1);                         \
  98     __asm __volatile (__lll_acq_instr ::: "memory");                          \
  99     if (__builtin_expect (__val != 0, 0))                                     \
 100       __lll_lock_wait (__futex, __val);                                       \
 101   })
 102
 103 extern int __lll_timedlock_wait
 104         (int *futex, int val, const struct timespec *) attribute_hidden;
 105
 106 #define lll_mutex_timedlock(lock, abstime) \
 107   ({ int *__futex = &(lock);                                                  \
 108      int __val = atomic_exchange_and_add (__futex, 1);                        \
 109      __asm __volatile (__lll_acq_instr ::: "memory");                         \
 110      if (__builtin_expect (__val != 0, 0))                                    \
 111        __val = __lll_timedlock_wait (__futex, __val, (abstime));              \
 112      __val;                                                                   \
 113   })
 114
 115 #define lll_mutex_unlock(lock) \
 116   ((void) ({                                                                  \
 117     int *__futex = &(lock);                                                   \
 118     int __val = atomic_exchange (__futex, 0);                                 \
 119     if (__builtin_expect (__val > 1, 0))                                      \
 120       lll_futex_wake (__futex, 1);                                            \
 121   }))
 122
 123 #define lll_mutex_islocked(futex) \
 124   (futex != 0)
 125
 126
 127 /* Our internal lock implementation is identical to the binary-compatible
 128    mutex implementation. */
 129
 130 /* Type for lock object.  */
 131 typedef int lll_lock_t;
 132
 133 /* Initializers for lock.  */
 134 #define LLL_LOCK_INITIALIZER            (0)
 135 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 136
 137 extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
 138
 139 /* The states of a lock are:
 140     0  -  untaken
 141     1  -  taken by one user
 142    >1  -  taken by more users */
 143
 144 #define lll_trylock(lock)       lll_mutex_trylock (lock)
 145 #define lll_lock(lock)          lll_mutex_lock (lock)
 146 #define lll_unlock(lock)        lll_mutex_unlock (lock)
 147 #define lll_islocked(lock)      lll_mutex_islocked (lock)
 148
 149 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
 150    wakeup when the clone terminates.  The memory location contains the
 151    thread ID while the clone is running and is reset to zero
 152    afterwards.  */
 153 #define lll_wait_tid(tid) \
 154   do {                                                                        \
 155     __typeof (tid) __tid;                                                     \
 156     while ((__tid = (tid)) != 0)                                              \
 157       lll_futex_wait (&(tid), __tid);                                         \
 158   } while (0)
 159
 160 extern int __lll_timedwait_tid (int *, const struct timespec *)
 161      attribute_hidden;
 162
 163 #define lll_timedwait_tid(tid, abstime) \
 164   ({                                                                          \
 165     int __res = 0;                                                            \
 166     if ((tid) != 0)                                                           \
 167       __res = __lll_timedwait_tid (&(tid), (abstime));                        \
 168     __res;                                                                    \
 169   })
 170
 171
 172 /* Conditional variable handling.  */
 173
 174 extern void __lll_cond_wait (pthread_cond_t *cond)
 175      attribute_hidden;
 176 extern int __lll_cond_timedwait (pthread_cond_t *cond,
 177                                  const struct timespec *abstime)
 178      attribute_hidden;
 179 extern void __lll_cond_wake (pthread_cond_t *cond)
 180      attribute_hidden;
 181 extern void __lll_cond_broadcast (pthread_cond_t *cond)
 182      attribute_hidden;
 183
 184 #define lll_cond_wait(cond) \
 185   __lll_cond_wait (cond)
 186 #define lll_cond_timedwait(cond, abstime) \
 187   __lll_cond_timedwait (cond, abstime)
 188 #define lll_cond_wake(cond) \
 189   __lll_cond_wake (cond)
 190 #define lll_cond_broadcast(cond) \
 191   __lll_cond_broadcast (cond)
 192
 193 #endif  /* lowlevellock.h */