1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * bignum support for Rockchip crypto
4 *
5 * Copyright (c) 2020 Rockchip Electronics Co., Ltd.
6 *
7 * Author: Lin Jinhan <troy.lin@rock-chips.com>
8 *
9 */
10 #include <linux/slab.h>
11
12 #include "rk_crypto_bignum.h"
13
14 #define DEFAULT_ENDIAN RK_BG_LITTILE_ENDIAN
15
16 #define BYTES2WORDS(bytes) (round_up((bytes), sizeof(u32)) / sizeof(u32))
17 #define WORDS2BYTES(words) ((words) * sizeof(u32))
18 #define RK_WORD_SIZE 32
19
rk_reverse_memcpy(void * dst,const void * src,u32 size)20 static void rk_reverse_memcpy(void *dst, const void *src, u32 size)
21 {
22 char *_dst = (char *)dst, *_src = (char *)src;
23 u32 i;
24
25 if (!dst || !src || !size)
26 return;
27
28 for (i = 0; i < size; ++i)
29 _dst[size - i - 1] = _src[i];
30 }
31
rk_bn_alloc(u32 max_size)32 struct rk_bignum *rk_bn_alloc(u32 max_size)
33 {
34 struct rk_bignum *bn;
35
36 bn = kzalloc(sizeof(*bn), GFP_KERNEL);
37 if (!bn)
38 return NULL;
39
40 bn->data = kzalloc(round_up(max_size, sizeof(u32)), GFP_KERNEL);
41 if (!bn->data) {
42 kfree(bn);
43 return NULL;
44 }
45
46 bn->n_words = BYTES2WORDS(max_size);
47
48 return bn;
49 }
50
rk_bn_free(struct rk_bignum * bn)51 void rk_bn_free(struct rk_bignum *bn)
52 {
53 if (!bn)
54 return;
55
56 if (bn->data) {
57 memset(bn->data, 0x00, WORDS2BYTES(bn->n_words));
58 kfree(bn->data);
59 }
60
61 kfree(bn);
62 }
63
rk_bn_set_data(struct rk_bignum * bn,const u8 * data,u32 size,enum bignum_endian endian)64 int rk_bn_set_data(struct rk_bignum *bn, const u8 *data, u32 size, enum bignum_endian endian)
65 {
66 if (!bn || !data)
67 return -EINVAL;
68
69 if (BYTES2WORDS(size) > bn->n_words)
70 return -EINVAL;
71
72 if (endian == DEFAULT_ENDIAN)
73 memcpy(bn->data, data, size);
74 else
75 rk_reverse_memcpy(bn->data, data, size);
76
77 return 0;
78 }
79
rk_bn_get_data(const struct rk_bignum * bn,u8 * data,u32 size,enum bignum_endian endian)80 int rk_bn_get_data(const struct rk_bignum *bn, u8 *data, u32 size, enum bignum_endian endian)
81 {
82 if (!bn || !data)
83 return -EINVAL;
84
85 if (size < WORDS2BYTES(bn->n_words))
86 return -EINVAL;
87
88 memset(data, 0x00, size);
89
90 if (endian == DEFAULT_ENDIAN)
91 memcpy(data + size - WORDS2BYTES(bn->n_words), bn->data, bn->n_words);
92 else
93 rk_reverse_memcpy(data + size - WORDS2BYTES(bn->n_words),
94 bn->data, WORDS2BYTES(bn->n_words));
95
96 return 0;
97 }
98
rk_bn_get_size(const struct rk_bignum * bn)99 u32 rk_bn_get_size(const struct rk_bignum *bn)
100 {
101 if (!bn)
102 return 0;
103
104 return WORDS2BYTES(bn->n_words);
105 }
106
107 /*
108 * @brief Returns the index of the highest 1 in |bn|.
109 * @param bn: the point of input data bignum.
110 * @return The index starts at 0 for the least significant bit.
111 * If src == zero, it will return -1
112 */
rk_bn_highest_bit(const struct rk_bignum * bn)113 int rk_bn_highest_bit(const struct rk_bignum *bn)
114 {
115 u32 w;
116 u32 b;
117
118 if (!bn || !bn->data || !bn->n_words)
119 return -1;
120
121 w = bn->data[bn->n_words - 1];
122
123 for (b = 0; b < RK_WORD_SIZE; b++) {
124 w >>= 1;
125 if (w == 0)
126 break;
127 }
128
129 return (int)(bn->n_words - 1) * RK_WORD_SIZE + b;
130 }
131