sysdeps/unix/sysv/linux/s390/lowlevellock.h

   1 /* Copyright (C) 2003-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Martin Schwidefsky <schwidefsky@de.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 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 #define SYS_futex               238
  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 IS_IN (libc) || 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 #define lll_futex_wait(futex, val, private) \
  79   lll_futex_timed_wait (futex, val, NULL, private)
  80
  81 #define lll_futex_timed_wait(futexp, val, timespec, private) \
  82   ({                                                                          \
  83     INTERNAL_SYSCALL_DECL (__err);                                            \
  84                                                                               \
  85     INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
  86                               __lll_private_flag (FUTEX_WAIT, private),       \
  87                               (val), (timespec));                             \
  88   })
  89
  90 #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
  91   ({                                                                          \
  92     INTERNAL_SYSCALL_DECL (__err);                                            \
  93     int __op = FUTEX_WAIT_BITSET | clockbit;                                  \
  94                                                                               \
  95     INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
  96                               __lll_private_flag (__op, private),             \
  97                               (val), (timespec), NULL /* Unused.  */,         \
  98                               FUTEX_BITSET_MATCH_ANY);                        \
  99   })
 100
 101 #define lll_futex_wake(futexp, nr, private) \
 102   ({                                                                          \
 103     INTERNAL_SYSCALL_DECL (__err);                                            \
 104                                                                               \
 105     INTERNAL_SYSCALL (futex, __err, 4, (futexp),                      \
 106                               __lll_private_flag (FUTEX_WAKE, private),       \
 107                               (nr), 0);                                       \
 108   })
 109
 110
 111 /* Returns non-zero if error happened, zero if success.  */
 112 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
 113   ({                                                                          \
 114     INTERNAL_SYSCALL_DECL (__err);                                            \
 115     long int __ret;                                                           \
 116                                                                               \
 117     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 118                               __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
 119                               (nr_wake), (nr_move), (mutex), (val));          \
 120     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 121   })
 122
 123 /* Returns non-zero if error happened, zero if success.  */
 124 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
 125   ({                                                                          \
 126     INTERNAL_SYSCALL_DECL (__err);                                            \
 127     long int __ret;                                                           \
 128                                                                               \
 129     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 130                               __lll_private_flag (FUTEX_WAKE_OP, private),    \
 131                               (nr_wake), (nr_wake2), (futexp2),               \
 132                               FUTEX_OP_CLEAR_WAKE_IF_GT_ONE);                 \
 133     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 134   })
 135
 136 /* Priority Inheritance support.  */
 137 #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
 138   lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
 139
 140 #define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit,      \
 141                                         mutex, private)                       \
 142   ({                                                                          \
 143     INTERNAL_SYSCALL_DECL (__err);                                            \
 144     int __op = FUTEX_WAIT_REQUEUE_PI | clockbit;                              \
 145                                                                               \
 146     INTERNAL_SYSCALL (futex, __err, 5, (futexp),                              \
 147                       __lll_private_flag (__op, private),                     \
 148                       (val), (timespec), mutex);                              \
 149   })
 150
 151 #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv)  \
 152   ({                                                                          \
 153     INTERNAL_SYSCALL_DECL (__err);                                            \
 154     long int __ret;                                                           \
 155                                                                               \
 156     __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp),                      \
 157                               __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
 158                               (nr_wake), (nr_move), (mutex), (val));          \
 159     INTERNAL_SYSCALL_ERROR_P (__ret, __err);                                  \
 160   })
 161
 162 #define lll_compare_and_swap(futex, oldval, newval, operation) \
 163   do {                                                                        \
 164     __typeof (futex) __futex = (futex);                                       \
 165     __asm __volatile ("   l   %1,%0\n"                                        \
 166                       "0: " operation "\n"                                    \
 167                       "   cs  %1,%2,%0\n"                                     \
 168                       "   jl  0b\n"                                           \
 169                       "1:"                                                    \
 170                       : "=Q" (*__futex), "=&d" (oldval), "=&d" (newval)       \
 171                       : "m" (*__futex) : "cc", "memory" );                    \
 172   } while (0)
 173
 174
 175 static inline int
 176 __attribute__ ((always_inline))
 177 __lll_trylock (int *futex)
 178 {
 179     unsigned int old;
 180
 181     __asm __volatile ("cs %0,%3,%1"
 182                        : "=d" (old), "=Q" (*futex)
 183                        : "0" (0), "d" (1), "m" (*futex) : "cc", "memory" );
 184     return old != 0;
 185 }
 186 #define lll_trylock(futex) __lll_trylock (&(futex))
 187
 188
 189 static inline int
 190 __attribute__ ((always_inline))
 191 __lll_cond_trylock (int *futex)
 192 {
 193     unsigned int old;
 194
 195     __asm __volatile ("cs %0,%3,%1"
 196                        : "=d" (old), "=Q" (*futex)
 197                        : "0" (0), "d" (2), "m" (*futex) : "cc", "memory" );
 198     return old != 0;
 199 }
 200 #define lll_cond_trylock(futex) __lll_cond_trylock (&(futex))
 201
 202
 203 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
 204 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
 205 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
 206
 207 static inline void
 208 __attribute__ ((always_inline))
 209 __lll_lock (int *futex, int private)
 210 {
 211   if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0)))
 212     {
 213       if (__builtin_constant_p (private) && private == LLL_PRIVATE)
 214         __lll_lock_wait_private (futex);
 215       else
 216         __lll_lock_wait (futex, private);
 217     }
 218 }
 219 #define lll_lock(futex, private) __lll_lock (&(futex), private)
 220
 221 static inline int
 222 __attribute__ ((always_inline))
 223 __lll_robust_lock (int *futex, int id, int private)
 224 {
 225   int result = 0;
 226   if (__builtin_expect (atomic_compare_and_exchange_bool_acq (futex, id, 0),
 227                         0))
 228     result = __lll_robust_lock_wait (futex, private);
 229   return result;
 230 }
 231 #define lll_robust_lock(futex, id, private) \
 232   __lll_robust_lock (&(futex), id, private)
 233
 234 static inline void
 235 __attribute__ ((always_inline))
 236 __lll_cond_lock (int *futex, int private)
 237 {
 238   if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 2, 0)))
 239     __lll_lock_wait (futex, private);
 240 }
 241 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
 242
 243 #define lll_robust_cond_lock(futex, id, private) \
 244   __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
 245
 246 extern int __lll_timedlock_wait
 247   (int *futex, const struct timespec *, int private) attribute_hidden;
 248 extern int __lll_robust_timedlock_wait
 249   (int *futex, const struct timespec *, int private) attribute_hidden;
 250
 251 static inline int
 252 __attribute__ ((always_inline))
 253 __lll_timedlock (int *futex, const struct timespec *abstime, int private)
 254 {
 255   int result = 0;
 256   if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0)))
 257     result = __lll_timedlock_wait (futex, abstime, private);
 258   return result;
 259 }
 260 #define lll_timedlock(futex, abstime, private) \
 261   __lll_timedlock (&(futex), abstime, private)
 262
 263 #ifdef ENABLE_LOCK_ELISION
 264 extern int __lll_timedlock_elision
 265   (int *futex, short *adapt_count, const struct timespec *timeout, int private)
 266   attribute_hidden;
 267
 268 # define lll_timedlock_elision(futex, adapt_count, timeout, private)    \
 269   __lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
 270 #endif
 271
 272 static inline int
 273 __attribute__ ((always_inline))
 274 __lll_robust_timedlock (int *futex, const struct timespec *abstime,
 275                         int id, int private)
 276 {
 277   int result = 0;
 278   if (__builtin_expect (atomic_compare_and_exchange_bool_acq (futex, id, 0),
 279                         0))
 280     result = __lll_robust_timedlock_wait (futex, abstime, private);
 281   return result;
 282 }
 283 #define lll_robust_timedlock(futex, abstime, id, private) \
 284   __lll_robust_timedlock (&(futex), abstime, id, private)
 285
 286
 287 #define __lll_unlock(futex, private) \
 288   (void)                                                                      \
 289     ({ int __oldval;                                                          \
 290        int __newval = 0;                                                      \
 291        int *__futexp = (futex);                                               \
 292                                                                               \
 293        lll_compare_and_swap (__futexp, __oldval, __newval, "slr %2,%2");      \
 294        if (__glibc_unlikely (__oldval > 1))                                   \
 295          lll_futex_wake (__futexp, 1, private);                               \
 296     })
 297 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
 298
 299
 300 #define __lll_robust_unlock(futex, private) \
 301   (void)                                                                      \
 302     ({ int __oldval;                                                          \
 303        int __newval = 0;                                                      \
 304        int *__futexp = (futex);                                               \
 305                                                                               \
 306        lll_compare_and_swap (__futexp, __oldval, __newval, "slr %2,%2");      \
 307        if (__glibc_unlikely (__oldval & FUTEX_WAITERS))                       \
 308          lll_futex_wake (__futexp, 1, private);                               \
 309     })
 310 #define lll_robust_unlock(futex, private) \
 311   __lll_robust_unlock(&(futex), private)
 312
 313 #define lll_islocked(futex) \
 314   (futex != 0)
 315
 316
 317 /* Initializers for lock.  */
 318 #define LLL_LOCK_INITIALIZER            (0)
 319 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 320
 321 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
 322    wakeup when the clone terminates.  The memory location contains the
 323    thread ID while the clone is running and is reset to zero
 324    afterwards.  */
 325 #define __lll_wait_tid(ptid) \
 326   do                                                                          \
 327     {                                                                         \
 328       int __tid;                                                              \
 329                                                                               \
 330       while ((__tid = *ptid) != 0)                                            \
 331         lll_futex_wait (ptid, __tid, LLL_SHARED);                             \
 332     }                                                                         \
 333   while (0)
 334 #define lll_wait_tid(tid) __lll_wait_tid(&(tid))
 335
 336 extern int __lll_timedwait_tid (int *, const struct timespec *)
 337      attribute_hidden;
 338
 339 #define lll_timedwait_tid(tid, abstime) \
 340   ({                                                                          \
 341     int __res = 0;                                                            \
 342     if ((tid) != 0)                                                           \
 343       __res = __lll_timedwait_tid (&(tid), (abstime));                        \
 344     __res;                                                                    \
 345   })
 346
 347 #ifdef ENABLE_LOCK_ELISION
 348 extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
 349   attribute_hidden;
 350
 351 extern int __lll_unlock_elision(int *futex, int private)
 352   attribute_hidden;
 353
 354 extern int __lll_trylock_elision(int *futex, short *adapt_count)
 355   attribute_hidden;
 356
 357 # define lll_lock_elision(futex, adapt_count, private) \
 358   __lll_lock_elision (&(futex), &(adapt_count), private)
 359 # define lll_unlock_elision(futex, private) \
 360   __lll_unlock_elision (&(futex), private)
 361 # define lll_trylock_elision(futex, adapt_count) \
 362   __lll_trylock_elision(&(futex), &(adapt_count))
 363 #endif
 364
 365 #endif  /* lowlevellock.h */