urcu/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
  26 #ifdef __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 #define FUTEX_WAIT              0
  31 #define FUTEX_WAKE              1
  32
  33 /*
  34  * sys_futex compatibility header.
  35  * Use *only* *either of* futex_noasync OR futex_async on a given address.
  36  *
  37  * futex_noasync cannot be executed in signal handlers, but ensures that
  38  * it will be put in a wait queue even in compatibility mode.
  39  *
  40  * futex_async is signal-handler safe for the wakeup. It uses polling
  41  * on the wait-side in compatibility mode.
  42  */
  43
  44 #ifdef CONFIG_URCU_HAVE_FUTEX
  45 #include <sys/syscall.h>
  46 #define futex(...)      syscall(__NR_futex, __VA_ARGS__)
  47 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3)    \
  48                 futex(uaddr, op, val, timeout, uaddr2, val3)
  49 #define futex_async(uaddr, op, val, timeout, uaddr2, val3)      \
  50                 futex(uaddr, op, val, timeout, uaddr2, val3)
  51 #else
  52 extern int compat_futex_noasync(int *uaddr, int op, int val,
  53         const struct timespec *timeout, int *uaddr2, int val3);
  54 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3)    \
  55                 compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3)
  56 extern int compat_futex_async(int *uaddr, int op, int val,
  57         const struct timespec *timeout, int *uaddr2, int val3);
  58 #define futex_async(uaddr, op, val, timeout, uaddr2, val3)      \
  59                 compat_futex_async(uaddr, op, val, timeout, uaddr2, val3)
  60 #endif
  61
  62 #ifdef __cplusplus
  63 }
  64 #endif
  65
  66 #endif /* _URCU_FUTEX_H */