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 <linux/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, src1: dst, src2: 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 */
74