1 | /* GPL HEADER START |
2 | * |
3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License version 2 only, |
7 | * as published by the Free Software Foundation. |
8 | * |
9 | * This program is distributed in the hope that it will be useful, but |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * General Public License version 2 for more details (a copy is included |
13 | * in the LICENSE file that accompanied this code). |
14 | * |
15 | * You should have received a copy of the GNU General Public License |
16 | * version 2 along with this program; If not, see http://www.gnu.org/licenses |
17 | * |
18 | * Please visit http://www.xyratex.com/contact if you need additional |
19 | * information or have any questions. |
20 | * |
21 | * GPL HEADER END |
22 | */ |
23 | |
24 | /* |
25 | * Copyright 2012 Xyratex Technology Limited |
26 | * |
27 | * Wrappers for kernel crypto shash api to pclmulqdq crc32 implementation. |
28 | */ |
29 | #include <linux/init.h> |
30 | #include <linux/module.h> |
31 | #include <linux/string.h> |
32 | #include <linux/kernel.h> |
33 | #include <linux/crc32.h> |
34 | #include <crypto/internal/hash.h> |
35 | #include <crypto/internal/simd.h> |
36 | |
37 | #include <asm/cpufeatures.h> |
38 | #include <asm/cpu_device_id.h> |
39 | #include <asm/simd.h> |
40 | |
41 | #define CHKSUM_BLOCK_SIZE 1 |
42 | #define CHKSUM_DIGEST_SIZE 4 |
43 | |
44 | #define PCLMUL_MIN_LEN 64L /* minimum size of buffer |
45 | * for crc32_pclmul_le_16 */ |
46 | #define SCALE_F 16L /* size of xmm register */ |
47 | #define SCALE_F_MASK (SCALE_F - 1) |
48 | |
49 | u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32); |
50 | |
51 | static u32 __attribute__((pure)) |
52 | crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len) |
53 | { |
54 | unsigned int iquotient; |
55 | unsigned int iremainder; |
56 | unsigned int prealign; |
57 | |
58 | if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !crypto_simd_usable()) |
59 | return crc32_le(crc, p, len); |
60 | |
61 | if ((long)p & SCALE_F_MASK) { |
62 | /* align p to 16 byte */ |
63 | prealign = SCALE_F - ((long)p & SCALE_F_MASK); |
64 | |
65 | crc = crc32_le(crc, p, len: prealign); |
66 | len -= prealign; |
67 | p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) & |
68 | ~SCALE_F_MASK); |
69 | } |
70 | iquotient = len & (~SCALE_F_MASK); |
71 | iremainder = len & SCALE_F_MASK; |
72 | |
73 | kernel_fpu_begin(); |
74 | crc = crc32_pclmul_le_16(buffer: p, len: iquotient, crc32: crc); |
75 | kernel_fpu_end(); |
76 | |
77 | if (iremainder) |
78 | crc = crc32_le(crc, p: p + iquotient, len: iremainder); |
79 | |
80 | return crc; |
81 | } |
82 | |
83 | static int crc32_pclmul_cra_init(struct crypto_tfm *tfm) |
84 | { |
85 | u32 *key = crypto_tfm_ctx(tfm); |
86 | |
87 | *key = 0; |
88 | |
89 | return 0; |
90 | } |
91 | |
92 | static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key, |
93 | unsigned int keylen) |
94 | { |
95 | u32 *mctx = crypto_shash_ctx(tfm: hash); |
96 | |
97 | if (keylen != sizeof(u32)) |
98 | return -EINVAL; |
99 | *mctx = le32_to_cpup(p: (__le32 *)key); |
100 | return 0; |
101 | } |
102 | |
103 | static int crc32_pclmul_init(struct shash_desc *desc) |
104 | { |
105 | u32 *mctx = crypto_shash_ctx(tfm: desc->tfm); |
106 | u32 *crcp = shash_desc_ctx(desc); |
107 | |
108 | *crcp = *mctx; |
109 | |
110 | return 0; |
111 | } |
112 | |
113 | static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data, |
114 | unsigned int len) |
115 | { |
116 | u32 *crcp = shash_desc_ctx(desc); |
117 | |
118 | *crcp = crc32_pclmul_le(crc: *crcp, p: data, len); |
119 | return 0; |
120 | } |
121 | |
122 | /* No final XOR 0xFFFFFFFF, like crc32_le */ |
123 | static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len, |
124 | u8 *out) |
125 | { |
126 | *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len)); |
127 | return 0; |
128 | } |
129 | |
130 | static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data, |
131 | unsigned int len, u8 *out) |
132 | { |
133 | return __crc32_pclmul_finup(crcp: shash_desc_ctx(desc), data, len, out); |
134 | } |
135 | |
136 | static int crc32_pclmul_final(struct shash_desc *desc, u8 *out) |
137 | { |
138 | u32 *crcp = shash_desc_ctx(desc); |
139 | |
140 | *(__le32 *)out = cpu_to_le32p(p: crcp); |
141 | return 0; |
142 | } |
143 | |
144 | static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data, |
145 | unsigned int len, u8 *out) |
146 | { |
147 | return __crc32_pclmul_finup(crcp: crypto_shash_ctx(tfm: desc->tfm), data, len, |
148 | out); |
149 | } |
150 | |
151 | static struct shash_alg alg = { |
152 | .setkey = crc32_pclmul_setkey, |
153 | .init = crc32_pclmul_init, |
154 | .update = crc32_pclmul_update, |
155 | .final = crc32_pclmul_final, |
156 | .finup = crc32_pclmul_finup, |
157 | .digest = crc32_pclmul_digest, |
158 | .descsize = sizeof(u32), |
159 | .digestsize = CHKSUM_DIGEST_SIZE, |
160 | .base = { |
161 | .cra_name = "crc32" , |
162 | .cra_driver_name = "crc32-pclmul" , |
163 | .cra_priority = 200, |
164 | .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, |
165 | .cra_blocksize = CHKSUM_BLOCK_SIZE, |
166 | .cra_ctxsize = sizeof(u32), |
167 | .cra_module = THIS_MODULE, |
168 | .cra_init = crc32_pclmul_cra_init, |
169 | } |
170 | }; |
171 | |
172 | static const struct x86_cpu_id crc32pclmul_cpu_id[] = { |
173 | X86_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL), |
174 | {} |
175 | }; |
176 | MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id); |
177 | |
178 | |
179 | static int __init crc32_pclmul_mod_init(void) |
180 | { |
181 | |
182 | if (!x86_match_cpu(match: crc32pclmul_cpu_id)) { |
183 | pr_info("PCLMULQDQ-NI instructions are not detected.\n" ); |
184 | return -ENODEV; |
185 | } |
186 | return crypto_register_shash(alg: &alg); |
187 | } |
188 | |
189 | static void __exit crc32_pclmul_mod_fini(void) |
190 | { |
191 | crypto_unregister_shash(alg: &alg); |
192 | } |
193 | |
194 | module_init(crc32_pclmul_mod_init); |
195 | module_exit(crc32_pclmul_mod_fini); |
196 | |
197 | MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>" ); |
198 | MODULE_LICENSE("GPL" ); |
199 | |
200 | MODULE_ALIAS_CRYPTO("crc32" ); |
201 | MODULE_ALIAS_CRYPTO("crc32-pclmul" ); |
202 | |