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      1 /*	$NetBSD: atomic_is_lock_free.c,v 1.3 2023/04/03 16:45:46 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2023 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __RCSID("$NetBSD: atomic_is_lock_free.c,v 1.3 2023/04/03 16:45:46 riastradh Exp $");
     31 
     32 #include <sys/types.h>
     33 
     34 #include <sys/stdbool.h>
     35 
     36 /*
     37  * XXX Work around clang's built-in __atomic_is_lock_free by having the
     38  * C name be different but using an asm rename to define the right
     39  * symbol.
     40  */
     41 bool __atomic_is_lock_free_hack(size_t, const volatile void *)
     42     __RENAME(__atomic_is_lock_free);
     43 #define	__atomic_is_lock_free	__atomic_is_lock_free_hack
     44 
     45 bool
     46 __atomic_is_lock_free(size_t n, const volatile void *p __unused)
     47 {
     48 
     49 	switch (n) {
     50 	case 1:
     51 		return __atomic_always_lock_free(1, 0);
     52 	case 2:
     53 		return __atomic_always_lock_free(2, 0);
     54 	case 4:
     55 		return __atomic_always_lock_free(4, 0);
     56 	case 8:
     57 		return __atomic_always_lock_free(8, 0);
     58 	case 16:
     59 		return __atomic_always_lock_free(16, 0);
     60 	default:
     61 		return false;
     62 	}
     63 }
     64