1/* Copyright (C) 2002-2020 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 37#ifndef __RTP__ 38# include <vxLib.h> 39# include <taskHookLib.h> 40#else /* __RTP__ */ 41# include <errno.h> 42#endif /* __RTP__ */ 43 44/* ----------------------------- Init-once ------------------------------- */ 45 46static void 47__release (__gthread_once_t ** __guard) 48{ 49 (*__guard)->busy = 0; 50} 51 52int 53__gthread_once (__gthread_once_t * __guard, void (*__func) (void)) 54{ 55 if (__guard->done) 56 return 0; 57 58 /* Busy-wait until we have exclusive access to the state. Check if 59 another thread managed to perform the init call in the interim. */ 60 61 while (!__TAS(&__guard->busy)) 62 { 63 if (__guard->done) 64 return 0; 65 taskDelay (1); 66 } 67 68 if (!__guard->done) 69 { 70#ifndef __USING_SJLJ_EXCEPTIONS__ 71 /* Setup a cleanup to release the guard when __func() throws an 72 exception. We cannot use this with SJLJ exceptions as 73 Unwind_Register calls __gthread_once, leading to an infinite 74 recursion. */ 75 __attribute__ ((cleanup (__release))) 76 __gthread_once_t *__temp = __guard; 77#endif 78 79 __func (); 80 __guard->done = 1; 81 } 82 83 __release(&__guard); 84 return 0; 85} 86 87#endif /* __GTHREADS */ 88