1/* Copyright (C) 2002-2022 Free Software Foundation, Inc.
2   Contributed by Zack Weinberg <zack@codesourcery.com>
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14for more details.
15
16Under Section 7 of GPL version 3, you are granted additional
17permissions described in the GCC Runtime Library Exception, version
183.1, as published by the Free Software Foundation.
19
20You should have received a copy of the GNU General Public License and
21a copy of the GCC Runtime Library Exception along with this program;
22see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23<http://www.gnu.org/licenses/>.  */
24
25/* Threads compatibility routines for libgcc2 for VxWorks.
26
27   This file implements the init-once service exposed by gthr-vxworks.h.  */
28
29#include "tconfig.h"
30#include "tsystem.h"
31#include "gthr.h"
32
33#if defined(__GTHREADS)
34
35#include <vxWorks.h>
36#include <taskLib.h>
37
38#ifndef __RTP__
39# include <vxLib.h>
40# include <taskHookLib.h>
41#else /* __RTP__ */
42# include <errno.h>
43#endif /* __RTP__ */
44
45/* ----------------------------- Init-once ------------------------------- */
46
47static void
48__release (__gthread_once_t ** __guard)
49{
50  (*__guard)->busy = 0;
51}
52
53int
54__gthread_once (__gthread_once_t * __guard, void (*__func) (void))
55{
56  if (__guard->done)
57    return 0;
58
59  /* Busy-wait until we have exclusive access to the state.  Check if
60     another thread managed to perform the init call in the interim.  */
61
62  while (!__TAS(&__guard->busy))
63    {
64      if (__guard->done)
65	return 0;
66      taskDelay (1);
67    }
68
69  if (!__guard->done)
70    {
71#ifndef __USING_SJLJ_EXCEPTIONS__
72      /* Setup a cleanup to release the guard when __func() throws an
73	 exception.  We cannot use this with SJLJ exceptions as
74	 Unwind_Register calls __gthread_once, leading to an infinite
75	 recursion.  */
76      __attribute__ ((cleanup (__release)))
77	__gthread_once_t *__temp = __guard;
78#endif
79
80      __func ();
81      __guard->done = 1;
82    }
83
84  __release(&__guard);
85  return 0;
86}
87
88#endif /* __GTHREADS */
89