urcu/futex.h

   1 #ifndef _URCU_FUTEX_H
   2 #define _URCU_FUTEX_H
   3
   4 /*
   5  * urcu-futex.h
   6  *
   7  * Userspace RCU - sys_futex/compat_futex header.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include <urcu/config.h>
  25 #include <stdint.h>
  26
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31 #define FUTEX_WAIT              0
  32 #define FUTEX_WAKE              1
  33
  34 /*
  35  * sys_futex compatibility header.
  36  * Use *only* *either of* futex_noasync OR futex_async on a given address.
  37  *
  38  * futex_noasync cannot be executed in signal handlers, but ensures that
  39  * it will be put in a wait queue even in compatibility mode.
  40  *
  41  * futex_async is signal-handler safe for the wakeup. It uses polling
  42  * on the wait-side in compatibility mode.
  43  */
  44
  45 #ifdef CONFIG_RCU_HAVE_FUTEX
  46 #include <sys/syscall.h>
  47 #define futex(...)      syscall(__NR_futex, __VA_ARGS__)
  48 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3)    \
  49                 futex(uaddr, op, val, timeout, uaddr2, val3)
  50 #define futex_async(uaddr, op, val, timeout, uaddr2, val3)      \
  51                 futex(uaddr, op, val, timeout, uaddr2, val3)
  52 #else
  53 extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val,
  54         const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
  55 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3)    \
  56                 compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3)
  57 extern int compat_futex_async(int32_t *uaddr, int op, int32_t val,
  58         const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
  59 #define futex_async(uaddr, op, val, timeout, uaddr2, val3)      \
  60                 compat_futex_async(uaddr, op, val, timeout, uaddr2, val3)
  61 #endif
  62
  63 #ifdef __cplusplus
  64 }
  65 #endif
  66
  67 #endif /* _URCU_FUTEX_H */