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  * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2.1 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #include <urcu/config.h>
  27 #include <stdint.h>
  28
  29 #ifdef __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 #define FUTEX_WAIT              0
  34 #define FUTEX_WAKE              1
  35
  36 /*
  37  * sys_futex compatibility header.
  38  * Use *only* *either of* futex_noasync OR futex_async on a given address.
  39  *
  40  * futex_noasync cannot be executed in signal handlers, but ensures that
  41  * it will be put in a wait queue even in compatibility mode.
  42  *
  43  * futex_async is signal-handler safe for the wakeup. It uses polling
  44  * on the wait-side in compatibility mode.
  45  *
  46  * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted
  47  * (returns EINTR).
  48  */
  49
  50 #ifdef CONFIG_RCU_HAVE_FUTEX
  51 #include <urcu/syscall-compat.h>
  52 #define futex(...)      syscall(__NR_futex, __VA_ARGS__)
  53 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3)    \
  54                 futex(uaddr, op, val, timeout, uaddr2, val3)
  55 #define futex_async(uaddr, op, val, timeout, uaddr2, val3)      \
  56                 futex(uaddr, op, val, timeout, uaddr2, val3)
  57 #else
  58 extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val,
  59         const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
  60 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3)    \
  61                 compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3)
  62 extern int compat_futex_async(int32_t *uaddr, int op, int32_t val,
  63         const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
  64 #define futex_async(uaddr, op, val, timeout, uaddr2, val3)      \
  65                 compat_futex_async(uaddr, op, val, timeout, uaddr2, val3)
  66 #endif
  67
  68 #ifdef __cplusplus
  69 }
  70 #endif
  71
  72 #endif /* _URCU_FUTEX_H */