ports/sysdeps/unix/sysv/linux/arm/nptl/lowlevellock.h

   1 /* Copyright (C) 2005-2014 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    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _LOWLEVELLOCK_H
  19 #define _LOWLEVELLOCK_H 1
  20
  21 #include <time.h>
  22 #include <sys/param.h>
  23 #include <bits/pthreadtypes.h>
  24 #include <atomic.h>
  25 #include <sysdep.h>
  26 #include <kernel-features.h>
  27
  28 #define FUTEX_WAIT              0
  29 #define FUTEX_WAKE              1
  30 #define FUTEX_REQUEUE           3
  31 #define FUTEX_CMP_REQUEUE       4
  32 #define FUTEX_WAKE_OP           5
  33 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE   ((4 << 24) | 1)
  34 #define FUTEX_LOCK_PI           6
  35 #define FUTEX_UNLOCK_PI         7
  36 #define FUTEX_TRYLOCK_PI        8
  37 #define FUTEX_WAIT_BITSET       9
  38 #define FUTEX_WAKE_BITSET       10
  39 #define FUTEX_WAIT_REQUEUE_PI   11
  40 #define FUTEX_CMP_REQUEUE_PI    12
  41 #define FUTEX_PRIVATE_FLAG      128
  42 #define FUTEX_CLOCK_REALTIME    256
  43
  44 #define FUTEX_BITSET_MATCH_ANY  0xffffffff
  45
  46 /* Values for 'private' parameter of locking macros.  Yes, the
  47    definition seems to be backwards.  But it is not.  The bit will be
  48    reversed before passing to the system call.  */
  49 #define LLL_PRIVATE     0
  50 #define LLL_SHARED      FUTEX_PRIVATE_FLAG
  51
  52
  53 #if !defined NOT_IN_libc || defined IS_IN_rtld
  54 /* In libc.so or ld.so all futexes are private.  */
  55 # ifdef __ASSUME_PRIVATE_FUTEX
  56 #  define __lll_private_flag(fl, private) \
  57   ((fl) | FUTEX_PRIVATE_FLAG)
  58 # else
  59 #  define __lll_private_flag(fl, private) \
  60   ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
  61 # endif
  62 #else
  63 # ifdef __ASSUME_PRIVATE_FUTEX
  64 #  define __lll_private_flag(fl, private) \
  65   (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
  66 # else
  67 #  define __lll_private_flag(fl, private) \
  68   (__builtin_constant_p (private)                                             \
  69    ? ((private) == 0                                                          \
  70       ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))            \
  71       : (fl))                                                                 \
  72    : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG)                                \
  73               & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
  74 # endif
  75 #endif
  76
  77
  78 #define lll_futex_wait(futexp, val, private) \
  79   lll_futex_timed_wait(futexp, val, NULL, private)
  80
  81 #define lll_futex_timed_wait(futexp, val, timespec, private) \
  82   ({                                                                          \
  83     INTERNAL_SYSCALL_DECL (__err);                                            \
  84     long int __ret;                                                           \
  85     __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
  86                               __lll_private_flag (FUTEX_WAIT, private),       \
  87                               (val), (timespec));                             \
  88     __ret;                                                                    \
  89   })
  90
  91 #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
  92   ({                                                                    \
  93     INTERNAL_SYSCALL_DECL (__err);                                      \
  94     long int __ret;                                                     \
  95     int __op = FUTEX_WAIT_BITSET | clockbit;                            \
  96     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                \
  97                               __lll_private_flag (__op, private),       \
  98                               (val), (timespec), NULL /* Unused.  */,   \
  99                               FUTEX_BITSET_MATCH_ANY);                  \
 100     __ret;                                                              \
 101   })
 102
 103 #define lll_futex_wake(futexp, nr, private) \
 104   ({                                                                          \
 105     INTERNAL_SYSCALL_DECL (__err);                                            \
 106     long int __ret;                                                           \
 107     __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
 108                               __lll_private_flag (FUTEX_WAKE, private),       \
 109                               (nr), 0);                                       \
 110     __ret;                                                                    \
 111   })
 112
 113 #define lll_robust_dead(futexv, private) \
 114   do                                                                          \
 115     {                                                                         \
 116       int *__futexp = &(futexv);                                              \
 117       atomic_or (__futexp, FUTEX_OWNER_DIED);                                 \
 118       lll_futex_wake (__futexp, 1, private);                                  \
 119     }                                                                         \
 120   while (0)
 121
 122 /* Returns non-zero if error happened, zero if success.  */
 123 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
 124   ({                                                                          \
 125     INTERNAL_SYSCALL_DECL (__err);                                            \
 126     long int __ret;                                                           \
 127     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 128                               __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
 129                               (nr_wake), (nr_move), (mutex), (val));          \
 130     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 131   })
 132
 133
 134 /* Returns non-zero if error happened, zero if success.  */
 135 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
 136   ({                                                                          \
 137     INTERNAL_SYSCALL_DECL (__err);                                            \
 138     long int __ret;                                                           \
 139     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 140                               __lll_private_flag (FUTEX_WAKE_OP, private),    \
 141                               (nr_wake), (nr_wake2), (futexp2),               \
 142                               FUTEX_OP_CLEAR_WAKE_IF_GT_ONE);                 \
 143     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 144   })
 145
 146 /* Priority Inheritance support.  */
 147 #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
 148   lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
 149
 150 #define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit,      \
 151                                         mutex, private)                       \
 152   ({                                                                          \
 153     INTERNAL_SYSCALL_DECL (__err);                                            \
 154     int __op = FUTEX_WAIT_REQUEUE_PI | clockbit;                              \
 155                                                                               \
 156     INTERNAL_SYSCALL (futex, __err, 5, (futexp),                              \
 157                       __lll_private_flag (__op, private),                     \
 158                       (val), (timespec), mutex);                              \
 159   })
 160
 161 #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv)  \
 162   ({                                                                          \
 163     INTERNAL_SYSCALL_DECL (__err);                                            \
 164     long int __ret;                                                           \
 165                                                                               \
 166     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 167                               __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
 168                               (nr_wake), (nr_move), (mutex), (val));          \
 169     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 170   })
 171
 172
 173 #define lll_trylock(lock)       \
 174   atomic_compare_and_exchange_val_acq(&(lock), 1, 0)
 175
 176 #define lll_cond_trylock(lock)  \
 177   atomic_compare_and_exchange_val_acq(&(lock), 2, 0)
 178
 179 #define __lll_robust_trylock(futex, id) \
 180   (atomic_compare_and_exchange_val_acq (futex, id, 0) != 0)
 181 #define lll_robust_trylock(lock, id) \
 182   __lll_robust_trylock (&(lock), id)
 183
 184 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
 185 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
 186 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
 187
 188 #define __lll_lock(futex, private)                                            \
 189   ((void) ({                                                                  \
 190     int *__futex = (futex);                                                   \
 191     if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex,       \
 192                                                                 1, 0), 0))    \
 193       {                                                                       \
 194         if (__builtin_constant_p (private) && (private) == LLL_PRIVATE)       \
 195           __lll_lock_wait_private (__futex);                                  \
 196         else                                                                  \
 197           __lll_lock_wait (__futex, private);                                 \
 198       }                                                                       \
 199   }))
 200 #define lll_lock(futex, private) __lll_lock (&(futex), private)
 201
 202
 203 #define __lll_robust_lock(futex, id, private)                                 \
 204   ({                                                                          \
 205     int *__futex = (futex);                                                   \
 206     int __val = 0;                                                            \
 207                                                                               \
 208     if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id,  \
 209                                                                 0), 0))       \
 210       __val = __lll_robust_lock_wait (__futex, private);                      \
 211     __val;                                                                    \
 212   })
 213 #define lll_robust_lock(futex, id, private) \
 214   __lll_robust_lock (&(futex), id, private)
 215
 216
 217 #define __lll_cond_lock(futex, private)                                       \
 218   ((void) ({                                                                  \
 219     int *__futex = (futex);                                                   \
 220     if (__builtin_expect (atomic_exchange_acq (__futex, 2), 0))               \
 221       __lll_lock_wait (__futex, private);                                     \
 222   }))
 223 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
 224
 225
 226 #define lll_robust_cond_lock(futex, id, private) \
 227   __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
 228
 229
 230 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
 231                                  int private) attribute_hidden;
 232 extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
 233                                         int private) attribute_hidden;
 234
 235 #define __lll_timedlock(futex, abstime, private)                              \
 236   ({                                                                          \
 237      int *__futex = (futex);                                                  \
 238      int __val = 0;                                                           \
 239                                                                               \
 240      if (__builtin_expect (atomic_exchange_acq (__futex, 1), 0))              \
 241        __val = __lll_timedlock_wait (__futex, abstime, private);              \
 242      __val;                                                                   \
 243   })
 244 #define lll_timedlock(futex, abstime, private) \
 245   __lll_timedlock (&(futex), abstime, private)
 246
 247
 248 #define __lll_robust_timedlock(futex, abstime, id, private)                   \
 249   ({                                                                          \
 250     int *__futex = (futex);                                                   \
 251     int __val = 0;                                                            \
 252                                                                               \
 253     if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id,  \
 254                                                                 0), 0))       \
 255       __val = __lll_robust_timedlock_wait (__futex, abstime, private);        \
 256     __val;                                                                    \
 257   })
 258 #define lll_robust_timedlock(futex, abstime, id, private) \
 259   __lll_robust_timedlock (&(futex), abstime, id, private)
 260
 261
 262 #define __lll_unlock(futex, private) \
 263   (void)                                                        \
 264     ({ int *__futex = (futex);                                  \
 265        int __oldval = atomic_exchange_rel (__futex, 0);         \
 266        if (__builtin_expect (__oldval > 1, 0))                  \
 267          lll_futex_wake (__futex, 1, private);                  \
 268     })
 269 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
 270
 271
 272 #define __lll_robust_unlock(futex, private) \
 273   (void)                                                        \
 274     ({ int *__futex = (futex);                                  \
 275        int __oldval = atomic_exchange_rel (__futex, 0);         \
 276        if (__builtin_expect (__oldval & FUTEX_WAITERS, 0))      \
 277          lll_futex_wake (__futex, 1, private);                  \
 278     })
 279 #define lll_robust_unlock(futex, private) \
 280   __lll_robust_unlock(&(futex), private)
 281
 282
 283 #define lll_islocked(futex) \
 284   (futex != 0)
 285
 286
 287 /* Our internal lock implementation is identical to the binary-compatible
 288    mutex implementation. */
 289
 290 /* Initializers for lock.  */
 291 #define LLL_LOCK_INITIALIZER            (0)
 292 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 293
 294 /* The states of a lock are:
 295     0  -  untaken
 296     1  -  taken by one user
 297    >1  -  taken by more users */
 298
 299 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
 300    wakeup when the clone terminates.  The memory location contains the
 301    thread ID while the clone is running and is reset to zero
 302    afterwards.  */
 303 #define lll_wait_tid(tid) \
 304   do {                                  \
 305     __typeof (tid) __tid;               \
 306     while ((__tid = (tid)) != 0)        \
 307       lll_futex_wait (&(tid), __tid, LLL_SHARED);\
 308   } while (0)
 309
 310 extern int __lll_timedwait_tid (int *, const struct timespec *)
 311      attribute_hidden;
 312
 313 #define lll_timedwait_tid(tid, abstime) \
 314   ({                                                    \
 315     int __res = 0;                                      \
 316     if ((tid) != 0)                                     \
 317       __res = __lll_timedwait_tid (&(tid), (abstime));  \
 318     __res;                                              \
 319   })
 320
 321 #endif  /* lowlevellock.h */