1 /* Copyright (C) 2002-2020 Free Software Foundation, Inc. 2 Contributed by Zack Weinberg <zack@codesourcery.com> 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see 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 46 static void 47 __release (__gthread_once_t ** __guard) 48 { 49 (*__guard)->busy = 0; 50 } 51 52 int 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