sysdeps/unix/sysv/linux/aarch64/lowlevellock.h

   1 /* Copyright (C) 2005-2014 Free Software Foundation, Inc.
   2
   3    This file is part of the GNU C Library.
   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 <sysdep.h>
  27 #include <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_WAIT_REQUEUE_PI   11
  41 #define FUTEX_CMP_REQUEUE_PI    12
  42 #define FUTEX_PRIVATE_FLAG      128
  43 #define FUTEX_CLOCK_REALTIME    256
  44
  45 #define FUTEX_BITSET_MATCH_ANY  0xffffffff
  46
  47 /* Values for 'private' parameter of locking macros.  Yes, the
  48    definition seems to be backwards.  But it is not.  The bit will be
  49    reversed before passing to the system call.  */
  50 #define LLL_PRIVATE     0
  51 #define LLL_SHARED      FUTEX_PRIVATE_FLAG
  52
  53
  54 #if !defined NOT_IN_libc || defined IS_IN_rtld
  55 /* In libc.so or ld.so all futexes are private.  */
  56 # ifdef __ASSUME_PRIVATE_FUTEX
  57 #  define __lll_private_flag(fl, private) \
  58   ((fl) | FUTEX_PRIVATE_FLAG)
  59 # else
  60 #  define __lll_private_flag(fl, private) \
  61   ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
  62 # endif
  63 #else
  64 # ifdef __ASSUME_PRIVATE_FUTEX
  65 #  define __lll_private_flag(fl, private) \
  66   (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
  67 # else
  68 #  define __lll_private_flag(fl, private) \
  69   (__builtin_constant_p (private)                                             \
  70    ? ((private) == 0                                                          \
  71       ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))            \
  72       : (fl))                                                                 \
  73    : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG)                                \
  74               & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
  75 # endif
  76 #endif
  77
  78
  79 #define lll_futex_wait(futexp, val, private) \
  80   lll_futex_timed_wait(futexp, val, NULL, private)
  81
  82 #define lll_futex_timed_wait(futexp, val, timespec, private) \
  83   ({                                                                          \
  84     INTERNAL_SYSCALL_DECL (__err);                                            \
  85     long int __ret;                                                           \
  86     __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
  87                               __lll_private_flag (FUTEX_WAIT, private),       \
  88                               (val), (timespec));                             \
  89     __ret;                                                                    \
  90   })
  91
  92 #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
  93   ({                                                                    \
  94     INTERNAL_SYSCALL_DECL (__err);                                      \
  95     long int __ret;                                                     \
  96     int __op = FUTEX_WAIT_BITSET | clockbit;                            \
  97     __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp),         \
  98                               __lll_private_flag (__op, private),       \
  99                               (val), (timespec), NULL /* Unused.  */,   \
 100                               FUTEX_BITSET_MATCH_ANY);                  \
 101     __ret;                                                              \
 102   })
 103
 104 #define lll_futex_wake(futexp, nr, private) \
 105   ({                                                                          \
 106     INTERNAL_SYSCALL_DECL (__err);                                            \
 107     long int __ret;                                                           \
 108     __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
 109                               __lll_private_flag (FUTEX_WAKE, private),       \
 110                               (nr), 0);                                       \
 111     __ret;                                                                    \
 112   })
 113
 114 #define lll_robust_dead(futexv, private) \
 115   do                                                                          \
 116     {                                                                         \
 117       int *__futexp = &(futexv);                                              \
 118       atomic_or (__futexp, FUTEX_OWNER_DIED);                                 \
 119       lll_futex_wake (__futexp, 1, private);                                  \
 120     }                                                                         \
 121   while (0)
 122
 123 /* Returns non-zero if error happened, zero if success.  */
 124 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
 125   ({                                                                          \
 126     INTERNAL_SYSCALL_DECL (__err);                                            \
 127     long int __ret;                                                           \
 128     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 129                               __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
 130                               (nr_wake), (nr_move), (mutex), (val));          \
 131     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 132   })
 133
 134
 135 /* Returns non-zero if error happened, zero if success.  */
 136 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
 137   ({                                                                          \
 138     INTERNAL_SYSCALL_DECL (__err);                                            \
 139     long int __ret;                                                           \
 140     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 141                               __lll_private_flag (FUTEX_WAKE_OP, private),    \
 142                               (nr_wake), (nr_wake2), (futexp2),               \
 143                               FUTEX_OP_CLEAR_WAKE_IF_GT_ONE);                 \
 144     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 145   })
 146
 147
 148 /* Priority Inheritance support.  */
 149 #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
 150   lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
 151
 152 #define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit,      \
 153                                         mutex, private)                       \
 154   ({                                                                          \
 155     INTERNAL_SYSCALL_DECL (__err);                                            \
 156     long int __ret;                                                           \
 157     int __op = FUTEX_WAIT_REQUEUE_PI | clockbit;                              \
 158                                                                               \
 159     __ret = INTERNAL_SYSCALL (futex, __err, 5, (futexp),                      \
 160                               __lll_private_flag (__op, private),             \
 161                               (val), (timespec), mutex);                      \
 162     INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret;                 \
 163   })
 164
 165 #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv)  \
 166   ({                                                                          \
 167     INTERNAL_SYSCALL_DECL (__err);                                            \
 168     long int __ret;                                                           \
 169                                                                               \
 170     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 171                               __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
 172                               (nr_wake), (nr_move), (mutex), (val));          \
 173     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 174   })
 175
 176
 177 #define lll_trylock(lock)       \
 178   atomic_compare_and_exchange_val_acq(&(lock), 1, 0)
 179
 180 #define lll_cond_trylock(lock)  \
 181   atomic_compare_and_exchange_val_acq(&(lock), 2, 0)
 182
 183 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
 184 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
 185 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
 186
 187 #define __lll_lock(futex, private)                                            \
 188   ((void) ({                                                                  \
 189     int *__futex = (futex);                                                   \
 190     if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex,       \
 191                                                                 1, 0), 0))    \
 192       {                                                                       \
 193         if (__builtin_constant_p (private) && (private) == LLL_PRIVATE)       \
 194           __lll_lock_wait_private (__futex);                                  \
 195         else                                                                  \
 196           __lll_lock_wait (__futex, private);                                 \
 197       }                                                                       \
 198   }))
 199 #define lll_lock(futex, private) __lll_lock (&(futex), private)
 200
 201
 202 #define __lll_robust_lock(futex, id, private)                                 \
 203   ({                                                                          \
 204     int *__futex = (futex);                                                   \
 205     int __val = 0;                                                            \
 206                                                                               \
 207     if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id,  \
 208                                                                 0), 0))       \
 209       __val = __lll_robust_lock_wait (__futex, private);                      \
 210     __val;                                                                    \
 211   })
 212 #define lll_robust_lock(futex, id, private) \
 213   __lll_robust_lock (&(futex), id, private)
 214
 215
 216 #define __lll_cond_lock(futex, private)                                       \
 217   ((void) ({                                                                  \
 218     int *__futex = (futex);                                                   \
 219     if (__builtin_expect (atomic_exchange_acq (__futex, 2), 0))               \
 220       __lll_lock_wait (__futex, private);                                     \
 221   }))
 222 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
 223
 224
 225 #define lll_robust_cond_lock(futex, id, private) \
 226   __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
 227
 228
 229 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
 230                                  int private) attribute_hidden;
 231 extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
 232                                         int private) attribute_hidden;
 233
 234 #define __lll_timedlock(futex, abstime, private)                              \
 235   ({                                                                          \
 236      int *__futex = (futex);                                                  \
 237      int __val = 0;                                                           \
 238                                                                               \
 239      if (__builtin_expect (atomic_exchange_acq (__futex, 1), 0))              \
 240        __val = __lll_timedlock_wait (__futex, abstime, private);              \
 241      __val;                                                                   \
 242   })
 243 #define lll_timedlock(futex, abstime, private) \
 244   __lll_timedlock (&(futex), abstime, private)
 245
 246
 247 #define __lll_robust_timedlock(futex, abstime, id, private)                   \
 248   ({                                                                          \
 249     int *__futex = (futex);                                                   \
 250     int __val = 0;                                                            \
 251                                                                               \
 252     if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id,  \
 253                                                                 0), 0))       \
 254       __val = __lll_robust_timedlock_wait (__futex, abstime, private);        \
 255     __val;                                                                    \
 256   })
 257 #define lll_robust_timedlock(futex, abstime, id, private) \
 258   __lll_robust_timedlock (&(futex), abstime, id, private)
 259
 260
 261 #define __lll_unlock(futex, private) \
 262   (void)                                                        \
 263     ({ int *__futex = (futex);                                  \
 264        int __oldval = atomic_exchange_rel (__futex, 0);         \
 265        if (__builtin_expect (__oldval > 1, 0))                  \
 266          lll_futex_wake (__futex, 1, private);                  \
 267     })
 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 */