src/util/futex.h

   1 /*
   2  * Copyright © 2015 Intel
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #ifndef UTIL_FUTEX_H
  25 #define UTIL_FUTEX_H
  26
  27 #if defined(HAVE_LINUX_FUTEX_H)
  28
  29 #include <limits.h>
  30 #include <stdint.h>
  31 #include <unistd.h>
  32 #include <linux/futex.h>
  33 #include <sys/syscall.h>
  34 #include <sys/time.h>
  35
  36 static inline long sys_futex(void *addr1, int op, int val1, const struct timespec *timeout, void *addr2, int val3)
  37 {
  38    return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3);
  39 }
  40
  41 static inline int futex_wake(uint32_t *addr, int count)
  42 {
  43    return sys_futex(addr, FUTEX_WAKE, count, NULL, NULL, 0);
  44 }
  45
  46 static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout)
  47 {
  48    /* FUTEX_WAIT_BITSET with FUTEX_BITSET_MATCH_ANY is equivalent to
  49     * FUTEX_WAIT, except that it treats the timeout as absolute. */
  50    return sys_futex(addr, FUTEX_WAIT_BITSET, value, timeout, NULL,
  51                     FUTEX_BITSET_MATCH_ANY);
  52 }
  53
  54 #endif
  55
  56 #endif /* UTIL_FUTEX_H */