src/freebsd/thread.c

   1 /*****************************************************************************
   2  * freebsd/thread.c: FreeBSD specifics for atomic wait
   3  *****************************************************************************
   4  * Copyright (C) 2020 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 #include <assert.h>
  26 #include <stddef.h>
  27 #include <errno.h>
  28 #include <limits.h>
  29 #include <sys/types.h>
  30 #include <pthread.h>
  31 #include <sys/thr.h>
  32 #include <sys/umtx.h>
  33
  34 #include <vlc_common.h>
  35
  36 unsigned long vlc_thread_id(void)
  37 {
  38      static _Thread_local int tid = -1;
  39
  40      if (unlikely(tid == -1))
  41          tid = thr_self();
  42
  43      return tid;
  44 }
  45
  46 static int vlc_umtx_wake(void *addr, int nr)
  47 {
  48     return _umtx_op(addr, UMTX_OP_WAKE_PRIVATE, nr, NULL, NULL);
  49 }
  50
  51 static int vlc_umtx_wait(void *addr, unsigned val, const struct timespec *ts)
  52 {
  53     struct _umtx_time to = {
  54         ._timeout = *ts,
  55         ._flags = UMTX_ABSTIME,
  56         ._clockid = CLOCK_MONOTONIC,
  57     };
  58     int type;
  59     /* "the uaddr value [...] must be equal to the size of the structure
  60      * pointed to by uaddr2, casted to uintptr_t."
  61      */
  62     void *uaddr = (void *)sizeof (to);
  63
  64     return _umtx_op(addr, UMTX_OP_WAIT_UINT_PRIVATE, val, uaddr, &to);
  65 }
  66
  67 void vlc_atomic_notify_one(void *addr)
  68 {
  69     vlc_umtx_wake(addr, 1);
  70 }
  71
  72 void vlc_atomic_notify_all(void *addr)
  73 {
  74     vlc_umtx_wake(addr, INT_MAX);
  75 }
  76
  77 void vlc_atomic_wait(void *addr, unsigned val)
  78 {
  79     int ret = vlc_umtx_wait(addr, val, NULL);
  80
  81     assert(ret == 0 || ret == EINTR || ret == ERESTART);
  82 }
  83
  84 int vlc_atomic_timedwait(void *addr, unsigned val, vlc_tick_t deadline)
  85 {
  86     struct timespec ts = timespec_from_vlc_tick(delay);
  87     int ret = vlc_umtx_wait(addr, val, &ts);
  88
  89     assert(ret == 0 || ret == ETIMEDOUT || ret == EINTR || ret == ERESTART);
  90     return (ret != ETIMEDOUT) ? 0 : ret;
  91 }