l4/pkg/uclibc/lib/contrib/uclibc/libpthread/nptl/sysdeps/unix/sysv/linux/metag/lowlevellock.h

   1 /* Copyright (C) 2005, 2006, 2007, 2008, 2009 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, 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 #include <bits/kernel-features.h>
  28
  29 #define FUTEX_WAIT              0
  30 #define FUTEX_WAKE              1
  31 #define FUTEX_REQUEUE           3
  32 #define FUTEX_CMP_REQUEUE       4
  33 #define FUTEX_WAKE_OP           5
  34 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE   ((4 << 24) | 1)
  35 #define FUTEX_LOCK_PI           6
  36 #define FUTEX_UNLOCK_PI         7
  37 #define FUTEX_TRYLOCK_PI        8
  38 #define FUTEX_WAIT_BITSET       9
  39 #define FUTEX_WAKE_BITSET       10
  40 #define FUTEX_PRIVATE_FLAG      128
  41 #define FUTEX_CLOCK_REALTIME    256
  42
  43 #define FUTEX_BITSET_MATCH_ANY  0xffffffff
  44
  45 /* Values for 'private' parameter of locking macros.  Yes, the
  46    definition seems to be backwards.  But it is not.  The bit will be
  47    reversed before passing to the system call.  */
  48 #define LLL_PRIVATE     0
  49 #define LLL_SHARED      FUTEX_PRIVATE_FLAG
  50
  51
  52 #if !defined NOT_IN_libc || defined IS_IN_rtld
  53 /* In libc.so or ld.so all futexes are private.  */
  54 # ifdef __ASSUME_PRIVATE_FUTEX
  55 #  define __lll_private_flag(fl, private) \
  56   ((fl) | FUTEX_PRIVATE_FLAG)
  57 # else
  58 #  define __lll_private_flag(fl, private) \
  59   ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
  60 # endif
  61 #else
  62 # ifdef __ASSUME_PRIVATE_FUTEX
  63 #  define __lll_private_flag(fl, private) \
  64   (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
  65 # else
  66 #  define __lll_private_flag(fl, private) \
  67   (__builtin_constant_p (private)                                             \
  68    ? ((private) == 0                                                          \
  69       ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))            \
  70       : (fl))                                                                 \
  71    : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG)                                \
  72               & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
  73 # endif
  74 #endif
  75
  76
  77 #define lll_futex_wait(futexp, val, private) \
  78   lll_futex_timed_wait(futexp, val, NULL, private)
  79
  80 #define lll_futex_timed_wait(futexp, val, timespec, private) \
  81   ({                                                                          \
  82     INTERNAL_SYSCALL_DECL (__err);                                            \
  83     long int __ret;                                                           \
  84     __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
  85                               __lll_private_flag (FUTEX_WAIT, private),       \
  86                               (val), (timespec));                             \
  87     __ret;                                                                    \
  88   })
  89
  90 #define lll_futex_wake(futexp, nr, private) \
  91   ({                                                                          \
  92     INTERNAL_SYSCALL_DECL (__err);                                            \
  93     long int __ret;                                                           \
  94     __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
  95                               __lll_private_flag (FUTEX_WAKE, private),       \
  96                               (nr), 0);                                       \
  97     __ret;                                                                    \
  98   })
  99
 100 #define lll_robust_dead(futexv, private) \
 101   do                                                                          \
 102     {                                                                         \
 103       int *__futexp = &(futexv);                                              \
 104       atomic_or (__futexp, FUTEX_OWNER_DIED);                                 \
 105       lll_futex_wake (__futexp, 1, private);                                  \
 106     }                                                                         \
 107   while (0)
 108
 109 /* Returns non-zero if error happened, zero if success.  */
 110 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
 111   ({                                                                          \
 112     INTERNAL_SYSCALL_DECL (__err);                                            \
 113     long int __ret;                                                           \
 114     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 115                               __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
 116                               (nr_wake), (nr_move), (mutex), (val));          \
 117     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 118   })
 119
 120
 121 /* Returns non-zero if error happened, zero if success.  */
 122 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
 123   ({                                                                          \
 124     INTERNAL_SYSCALL_DECL (__err);                                            \
 125     long int __ret;                                                           \
 126     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 127                               __lll_private_flag (FUTEX_WAKE_OP, private),    \
 128                               (nr_wake), (nr_wake2), (futexp2),               \
 129                               FUTEX_OP_CLEAR_WAKE_IF_GT_ONE);                 \
 130     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 131   })
 132
 133
 134 #define lll_trylock(lock)       \
 135   atomic_compare_and_exchange_val_acq(&(lock), 1, 0)
 136
 137 #define lll_cond_trylock(lock)  \
 138   atomic_compare_and_exchange_val_acq(&(lock), 2, 0)
 139
 140 #define __lll_robust_trylock(futex, id) \
 141   (atomic_compare_and_exchange_val_acq (futex, id, 0) != 0)
 142 #define lll_robust_trylock(lock, id) \
 143   __lll_robust_trylock (&(lock), id)
 144
 145 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
 146 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
 147 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
 148
 149 #define __lll_lock(futex, private)                                            \
 150   ((void) ({                                                                  \
 151     int *__futex = (futex);                                                   \
 152     if (unlikely(atomic_compare_and_exchange_val_acq (__futex, 1, 0)))        \
 153       {                                                                       \
 154         if (__builtin_constant_p (private) && (private) == LLL_PRIVATE)       \
 155           __lll_lock_wait_private (__futex);                                  \
 156         else                                                                  \
 157           __lll_lock_wait (__futex, private);                                 \
 158       }                                                                       \
 159   }))
 160 #define lll_lock(futex, private) __lll_lock (&(futex), private)
 161
 162
 163 #define __lll_robust_lock(futex, id, private)                                 \
 164   ({                                                                          \
 165     int *__futex = (futex);                                                   \
 166     int __val = 0;                                                            \
 167                                                                               \
 168     if (unlikely(atomic_compare_and_exchange_bool_acq (__futex, id, 0)))      \
 169       __val = __lll_robust_lock_wait (__futex, private);                      \
 170     __val;                                                                    \
 171   })
 172 #define lll_robust_lock(futex, id, private) \
 173   __lll_robust_lock (&(futex), id, private)
 174
 175
 176 #define __lll_cond_lock(futex, private)                                       \
 177   ((void) ({                                                                  \
 178     int *__futex = (futex);                                                   \
 179     if (unlikely(atomic_exchange_acq (__futex, 2)))                           \
 180       __lll_lock_wait (__futex, private);                                     \
 181   }))
 182 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
 183
 184
 185 #define lll_robust_cond_lock(futex, id, private) \
 186   __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
 187
 188
 189 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
 190                                  int private) attribute_hidden;
 191 extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
 192                                         int private) attribute_hidden;
 193
 194 #define __lll_timedlock(futex, abstime, private)                              \
 195   ({                                                                          \
 196      int *__futex = (futex);                                                  \
 197      int __val = 0;                                                           \
 198                                                                               \
 199      if (unlikely(atomic_exchange_acq (__futex, 1)))                          \
 200        __val = __lll_timedlock_wait (__futex, abstime, private);              \
 201      __val;                                                                   \
 202   })
 203 #define lll_timedlock(futex, abstime, private) \
 204   __lll_timedlock (&(futex), abstime, private)
 205
 206
 207 #define __lll_robust_timedlock(futex, abstime, id, private)                   \
 208   ({                                                                          \
 209     int *__futex = (futex);                                                   \
 210     int __val = 0;                                                            \
 211                                                                               \
 212     if (unlikely(atomic_compare_and_exchange_bool_acq (__futex, id, 0)))      \
 213       __val = __lll_robust_timedlock_wait (__futex, abstime, private);        \
 214     __val;                                                                    \
 215   })
 216 #define lll_robust_timedlock(futex, abstime, id, private) \
 217   __lll_robust_timedlock (&(futex), abstime, id, private)
 218
 219
 220 #define __lll_unlock(futex, private) \
 221   (void)                                                        \
 222     ({ int *__futex = (futex);                                  \
 223        int __oldval = atomic_exchange_rel (__futex, 0);         \
 224        if (unlikely(__oldval > 1))                              \
 225          lll_futex_wake (__futex, 1, private);                  \
 226     })
 227 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
 228
 229
 230 #define __lll_robust_unlock(futex, private) \
 231   (void)                                                        \
 232     ({ int *__futex = (futex);                                  \
 233        int __oldval = atomic_exchange_rel (__futex, 0);         \
 234        if (unlikely(__oldval & FUTEX_WAITERS))                  \
 235          lll_futex_wake (__futex, 1, private);                  \
 236     })
 237 #define lll_robust_unlock(futex, private) \
 238   __lll_robust_unlock(&(futex), private)
 239
 240
 241 #define lll_islocked(futex) \
 242   (futex != 0)
 243
 244
 245 /* Our internal lock implementation is identical to the binary-compatible
 246    mutex implementation. */
 247
 248 /* Initializers for lock.  */
 249 #define LLL_LOCK_INITIALIZER            (0)
 250 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 251
 252 /* The states of a lock are:
 253     0  -  untaken
 254     1  -  taken by one user
 255    >1  -  taken by more users */
 256
 257 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
 258    wakeup when the clone terminates.  The memory location contains the
 259    thread ID while the clone is running and is reset to zero
 260    afterwards.  */
 261 #define lll_wait_tid(tid) \
 262   do {                                  \
 263     __typeof (tid) __tid;               \
 264     while ((__tid = (tid)) != 0)        \
 265       lll_futex_wait (&(tid), __tid, LLL_SHARED);\
 266   } while (0)
 267
 268 extern int __lll_timedwait_tid (int *, const struct timespec *)
 269      attribute_hidden;
 270
 271 #define lll_timedwait_tid(tid, abstime) \
 272   ({                                                    \
 273     int __res = 0;                                      \
 274     if ((tid) != 0)                                     \
 275       __res = __lll_timedwait_tid (&(tid), (abstime));  \
 276     __res;                                              \
 277   })
 278
 279 #endif  /* lowlevellock.h */