xref: /freebsd/sys/compat/linuxkpi/common/include/linux/overflow.h (revision 3332f1b444d4a73238e9f59cca27bfc95fe936bd)
1 /*-
2  * Copyright (c) 2020 The FreeBSD Foundation
3  *
4  * This software was developed by Emmanuel Vadot under sponsorship
5  * from the FreeBSD Foundation.
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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #ifndef __LINUX_OVERFLOW_H__
32 #define	__LINUX_OVERFLOW_H__
33 
34 #include <sys/stdint.h>
35 #include <sys/types.h>
36 
37 #define check_add_overflow(a, b, c)		\
38 	__builtin_add_overflow(a, b, c)
39 
40 #define check_mul_overflow(a, b, c)	\
41 	__builtin_mul_overflow(a, b, c)
42 
43 static inline size_t
44 array_size(size_t x, size_t y)
45 {
46 	size_t retval;
47 
48 	if (__builtin_mul_overflow(x, y, &retval))
49 		retval = SIZE_MAX;
50 	return (retval);
51 }
52 
53 #endif	/* __LINUX_OVERFLOW_H__ */
54