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 #define UTIL_FUTEX_SUPPORTED 1
  29
  30 #include <limits.h>
  31 #include <stdint.h>
  32 #include <unistd.h>
  33 #include <linux/futex.h>
  34 #include <sys/syscall.h>
  35 #include <sys/time.h>
  36
  37 static inline long sys_futex(void *addr1, int op, int val1, const struct timespec *timeout, void *addr2, int val3)
  38 {
  39    return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3);
  40 }
  41
  42 static inline int futex_wake(uint32_t *addr, int count)
  43 {
  44    return sys_futex(addr, FUTEX_WAKE, count, NULL, NULL, 0);
  45 }
  46
  47 static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout)
  48 {
  49    /* FUTEX_WAIT_BITSET with FUTEX_BITSET_MATCH_ANY is equivalent to
  50     * FUTEX_WAIT, except that it treats the timeout as absolute. */
  51    return sys_futex(addr, FUTEX_WAIT_BITSET, value, timeout, NULL,
  52                     FUTEX_BITSET_MATCH_ANY);
  53 }
  54
  55 #elif defined(__FreeBSD__)
  56 #define UTIL_FUTEX_SUPPORTED 1
  57
  58 #include <assert.h>
  59 #include <errno.h>
  60 #include <fcntl.h>
  61 #include <sys/types.h>
  62 #include <sys/umtx.h>
  63 #include <sys/time.h>
  64
  65 static inline int futex_wake(uint32_t *addr, int count)
  66 {
  67    assert(count == (int)(uint32_t)count); /* Check that bits weren't discarded */
  68    return _umtx_op(addr, UMTX_OP_WAKE, (uint32_t)count, NULL, NULL) == -1 ? errno : 0;
  69 }
  70
  71 static inline int futex_wait(uint32_t *addr, int32_t value, struct timespec *timeout)
  72 {
  73    void *uaddr = NULL, *uaddr2 = NULL;
  74    struct _umtx_time tmo = {
  75       ._flags = UMTX_ABSTIME,
  76       ._clockid = CLOCK_MONOTONIC
  77    };
  78
  79    assert(value == (int)(uint32_t)value); /* Check that bits weren't discarded */
  80
  81    if (timeout != NULL) {
  82       tmo._timeout = *timeout;
  83       uaddr = (void *)(uintptr_t)sizeof(tmo);
  84       uaddr2 = (void *)&tmo;
  85    }
  86
  87    return _umtx_op(addr, UMTX_OP_WAIT_UINT, (uint32_t)value, uaddr, uaddr2) == -1 ? errno : 0;
  88 }
  89
  90 #elif defined(__OpenBSD__)
  91 #define UTIL_FUTEX_SUPPORTED 1
  92
  93 #include <sys/time.h>
  94 #include <sys/futex.h>
  95
  96 static inline int futex_wake(uint32_t *addr, int count)
  97 {
  98    return futex(addr, FUTEX_WAKE, count, NULL, NULL);
  99 }
 100
 101 static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout)
 102 {
 103    struct timespec tsrel, tsnow;
 104    clock_gettime(CLOCK_MONOTONIC, &tsnow);
 105    timespecsub(timeout, &tsrel, &tsrel);
 106    return futex(addr, FUTEX_WAIT, value, &tsrel, NULL);
 107 }
 108
 109 #else
 110 #define UTIL_FUTEX_SUPPORTED 0
 111 #endif
 112
 113 #endif /* UTIL_FUTEX_H */