1/* SPDX-License-Identifier: GPL-2.0-or-later */
 2/*
 3 * Cryptographic utilities
 4 *
 5 * Copyright (c) 2023 Herbert Xu <herbert@gondor.apana.org.au>
 6 */
 7#ifndef _CRYPTO_UTILS_H
 8#define _CRYPTO_UTILS_H
 9
10#include <asm/unaligned.h>
11#include <linux/compiler_attributes.h>
12#include <linux/types.h>
13
14void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int size);
15
16static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
17{
18	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
19	    __builtin_constant_p(size) &&
20	    (size % sizeof(unsigned long)) == 0) {
21		unsigned long *d = (unsigned long *)dst;
22		unsigned long *s = (unsigned long *)src;
23		unsigned long l;
24
25		while (size > 0) {
26			l = get_unaligned(d) ^ get_unaligned(s++);
27			put_unaligned(l, d++);
28			size -= sizeof(unsigned long);
29		}
30	} else {
31		__crypto_xor(dst, dst, src, size);
32	}
33}
34
35static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2,
36				  unsigned int size)
37{
38	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
39	    __builtin_constant_p(size) &&
40	    (size % sizeof(unsigned long)) == 0) {
41		unsigned long *d = (unsigned long *)dst;
42		unsigned long *s1 = (unsigned long *)src1;
43		unsigned long *s2 = (unsigned long *)src2;
44		unsigned long l;
45
46		while (size > 0) {
47			l = get_unaligned(s1++) ^ get_unaligned(s2++);
48			put_unaligned(l, d++);
49			size -= sizeof(unsigned long);
50		}
51	} else {
52		__crypto_xor(dst, src1, src2, size);
53	}
54}
55
56noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t size);
57
58/**
59 * crypto_memneq - Compare two areas of memory without leaking
60 *		   timing information.
61 *
62 * @a: One area of memory
63 * @b: Another area of memory
64 * @size: The size of the area.
65 *
66 * Returns 0 when data is equal, 1 otherwise.
67 */
68static inline int crypto_memneq(const void *a, const void *b, size_t size)
69{
70	return __crypto_memneq(a, b, size) != 0UL ? 1 : 0;
71}
72
73#endif	/* _CRYPTO_UTILS_H */