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compiler.h revision 1.6 
      1 /*	$NetBSD: compiler.h,v 1.6 2021/12/19 11:26:57 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2018 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef	_LINUX_COMPILER_H_
     33 #define	_LINUX_COMPILER_H_
     34 
     35 #include <sys/atomic.h>
     36 #include <sys/cdefs.h>
     37 
     38 #include <linux/stddef.h>
     39 
     40 #include <asm/barrier.h>
     41 
     42 #define	__printf	__printflike
     43 #define	__user
     44 #if __GNUC_PREREQ__(4,0)	/* not sure when but this will work */
     45 #define	__must_check	__attribute__((warn_unused_result))
     46 #else
     47 #define	__must_check	/* nothing */
     48 #endif
     49 #define	__always_unused	__unused
     50 #define	__maybe_unused	__unused
     51 #define	noinline	__noinline
     52 #define	__deprecated	/* nothing */
     53 
     54 #define	barrier()	__insn_barrier()
     55 #define	likely(X)	__predict_true(X)
     56 #define	unlikely(X)	__predict_false(X)
     57 #define	__same_type(X,Y)						      \
     58 	__builtin_types_compatible_p(__typeof__(X), __typeof__(Y))
     59 #define	__must_be_array(X)						      \
     60 	BUILD_BUG_ON_ZERO(__same_type((X), &(X)[0]))
     61 
     62 #define	READ_ONCE(X)	({						      \
     63 	typeof(X) __read_once_tmp = (X);				      \
     64 	membar_datadep_consumer();					      \
     65 	__read_once_tmp;						      \
     66 })
     67 
     68 #define	WRITE_ONCE(X, V)	({					      \
     69 	typeof(X) __write_once_tmp = (V);				      \
     70 	(X) = __write_once_tmp;						      \
     71 	__write_once_tmp;						      \
     72 })
     73 
     74 #define	smp_store_mb(X, V)	do {					      \
     75 	WRITE_ONCE(X, V);						      \
     76 	smp_mb();							      \
     77 } while (0)
     78 
     79 #define	smp_store_release(X, V)	do {					      \
     80 	typeof(X) __smp_store_release_tmp = (V);			      \
     81 	membar_exit();							      \
     82 	(X) = __write_once_tmp;						      \
     83 } while (0)
     84 
     85 #endif	/* _LINUX_COMPILER_H_ */
     86