1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions |
4 | * |
5 | * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org> |
6 | */ |
7 | |
8 | #include <linux/cpufeature.h> |
9 | #include <linux/crc32.h> |
10 | #include <linux/init.h> |
11 | #include <linux/kernel.h> |
12 | #include <linux/module.h> |
13 | #include <linux/string.h> |
14 | |
15 | #include <crypto/internal/hash.h> |
16 | #include <crypto/internal/simd.h> |
17 | |
18 | #include <asm/hwcap.h> |
19 | #include <asm/neon.h> |
20 | #include <asm/simd.h> |
21 | #include <asm/unaligned.h> |
22 | |
23 | #define PMULL_MIN_LEN 64L /* minimum size of buffer |
24 | * for crc32_pmull_le_16 */ |
25 | #define SCALE_F 16L /* size of NEON register */ |
26 | |
27 | asmlinkage u32 crc32_pmull_le(const u8 buf[], u32 len, u32 init_crc); |
28 | asmlinkage u32 crc32_armv8_le(u32 init_crc, const u8 buf[], u32 len); |
29 | |
30 | asmlinkage u32 crc32c_pmull_le(const u8 buf[], u32 len, u32 init_crc); |
31 | asmlinkage u32 crc32c_armv8_le(u32 init_crc, const u8 buf[], u32 len); |
32 | |
33 | static u32 (*fallback_crc32)(u32 init_crc, const u8 buf[], u32 len); |
34 | static u32 (*fallback_crc32c)(u32 init_crc, const u8 buf[], u32 len); |
35 | |
36 | static int crc32_cra_init(struct crypto_tfm *tfm) |
37 | { |
38 | u32 *key = crypto_tfm_ctx(tfm); |
39 | |
40 | *key = 0; |
41 | return 0; |
42 | } |
43 | |
44 | static int crc32c_cra_init(struct crypto_tfm *tfm) |
45 | { |
46 | u32 *key = crypto_tfm_ctx(tfm); |
47 | |
48 | *key = ~0; |
49 | return 0; |
50 | } |
51 | |
52 | static int crc32_setkey(struct crypto_shash *hash, const u8 *key, |
53 | unsigned int keylen) |
54 | { |
55 | u32 *mctx = crypto_shash_ctx(tfm: hash); |
56 | |
57 | if (keylen != sizeof(u32)) |
58 | return -EINVAL; |
59 | *mctx = le32_to_cpup(p: (__le32 *)key); |
60 | return 0; |
61 | } |
62 | |
63 | static int crc32_init(struct shash_desc *desc) |
64 | { |
65 | u32 *mctx = crypto_shash_ctx(tfm: desc->tfm); |
66 | u32 *crc = shash_desc_ctx(desc); |
67 | |
68 | *crc = *mctx; |
69 | return 0; |
70 | } |
71 | |
72 | static int crc32_update(struct shash_desc *desc, const u8 *data, |
73 | unsigned int length) |
74 | { |
75 | u32 *crc = shash_desc_ctx(desc); |
76 | |
77 | *crc = crc32_armv8_le(init_crc: *crc, buf: data, len: length); |
78 | return 0; |
79 | } |
80 | |
81 | static int crc32c_update(struct shash_desc *desc, const u8 *data, |
82 | unsigned int length) |
83 | { |
84 | u32 *crc = shash_desc_ctx(desc); |
85 | |
86 | *crc = crc32c_armv8_le(init_crc: *crc, buf: data, len: length); |
87 | return 0; |
88 | } |
89 | |
90 | static int crc32_final(struct shash_desc *desc, u8 *out) |
91 | { |
92 | u32 *crc = shash_desc_ctx(desc); |
93 | |
94 | put_unaligned_le32(val: *crc, p: out); |
95 | return 0; |
96 | } |
97 | |
98 | static int crc32c_final(struct shash_desc *desc, u8 *out) |
99 | { |
100 | u32 *crc = shash_desc_ctx(desc); |
101 | |
102 | put_unaligned_le32(val: ~*crc, p: out); |
103 | return 0; |
104 | } |
105 | |
106 | static int crc32_pmull_update(struct shash_desc *desc, const u8 *data, |
107 | unsigned int length) |
108 | { |
109 | u32 *crc = shash_desc_ctx(desc); |
110 | unsigned int l; |
111 | |
112 | if (crypto_simd_usable()) { |
113 | if ((u32)data % SCALE_F) { |
114 | l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F)); |
115 | |
116 | *crc = fallback_crc32(*crc, data, l); |
117 | |
118 | data += l; |
119 | length -= l; |
120 | } |
121 | |
122 | if (length >= PMULL_MIN_LEN) { |
123 | l = round_down(length, SCALE_F); |
124 | |
125 | kernel_neon_begin(); |
126 | *crc = crc32_pmull_le(buf: data, len: l, init_crc: *crc); |
127 | kernel_neon_end(); |
128 | |
129 | data += l; |
130 | length -= l; |
131 | } |
132 | } |
133 | |
134 | if (length > 0) |
135 | *crc = fallback_crc32(*crc, data, length); |
136 | |
137 | return 0; |
138 | } |
139 | |
140 | static int crc32c_pmull_update(struct shash_desc *desc, const u8 *data, |
141 | unsigned int length) |
142 | { |
143 | u32 *crc = shash_desc_ctx(desc); |
144 | unsigned int l; |
145 | |
146 | if (crypto_simd_usable()) { |
147 | if ((u32)data % SCALE_F) { |
148 | l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F)); |
149 | |
150 | *crc = fallback_crc32c(*crc, data, l); |
151 | |
152 | data += l; |
153 | length -= l; |
154 | } |
155 | |
156 | if (length >= PMULL_MIN_LEN) { |
157 | l = round_down(length, SCALE_F); |
158 | |
159 | kernel_neon_begin(); |
160 | *crc = crc32c_pmull_le(buf: data, len: l, init_crc: *crc); |
161 | kernel_neon_end(); |
162 | |
163 | data += l; |
164 | length -= l; |
165 | } |
166 | } |
167 | |
168 | if (length > 0) |
169 | *crc = fallback_crc32c(*crc, data, length); |
170 | |
171 | return 0; |
172 | } |
173 | |
174 | static struct shash_alg crc32_pmull_algs[] = { { |
175 | .setkey = crc32_setkey, |
176 | .init = crc32_init, |
177 | .update = crc32_update, |
178 | .final = crc32_final, |
179 | .descsize = sizeof(u32), |
180 | .digestsize = sizeof(u32), |
181 | |
182 | .base.cra_ctxsize = sizeof(u32), |
183 | .base.cra_init = crc32_cra_init, |
184 | .base.cra_name = "crc32" , |
185 | .base.cra_driver_name = "crc32-arm-ce" , |
186 | .base.cra_priority = 200, |
187 | .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, |
188 | .base.cra_blocksize = 1, |
189 | .base.cra_module = THIS_MODULE, |
190 | }, { |
191 | .setkey = crc32_setkey, |
192 | .init = crc32_init, |
193 | .update = crc32c_update, |
194 | .final = crc32c_final, |
195 | .descsize = sizeof(u32), |
196 | .digestsize = sizeof(u32), |
197 | |
198 | .base.cra_ctxsize = sizeof(u32), |
199 | .base.cra_init = crc32c_cra_init, |
200 | .base.cra_name = "crc32c" , |
201 | .base.cra_driver_name = "crc32c-arm-ce" , |
202 | .base.cra_priority = 200, |
203 | .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, |
204 | .base.cra_blocksize = 1, |
205 | .base.cra_module = THIS_MODULE, |
206 | } }; |
207 | |
208 | static int __init crc32_pmull_mod_init(void) |
209 | { |
210 | if (elf_hwcap2 & HWCAP2_PMULL) { |
211 | crc32_pmull_algs[0].update = crc32_pmull_update; |
212 | crc32_pmull_algs[1].update = crc32c_pmull_update; |
213 | |
214 | if (elf_hwcap2 & HWCAP2_CRC32) { |
215 | fallback_crc32 = crc32_armv8_le; |
216 | fallback_crc32c = crc32c_armv8_le; |
217 | } else { |
218 | fallback_crc32 = crc32_le; |
219 | fallback_crc32c = __crc32c_le; |
220 | } |
221 | } else if (!(elf_hwcap2 & HWCAP2_CRC32)) { |
222 | return -ENODEV; |
223 | } |
224 | |
225 | return crypto_register_shashes(algs: crc32_pmull_algs, |
226 | ARRAY_SIZE(crc32_pmull_algs)); |
227 | } |
228 | |
229 | static void __exit crc32_pmull_mod_exit(void) |
230 | { |
231 | crypto_unregister_shashes(algs: crc32_pmull_algs, |
232 | ARRAY_SIZE(crc32_pmull_algs)); |
233 | } |
234 | |
235 | static const struct cpu_feature __maybe_unused crc32_cpu_feature[] = { |
236 | { cpu_feature(CRC32) }, { cpu_feature(PMULL) }, { } |
237 | }; |
238 | MODULE_DEVICE_TABLE(cpu, crc32_cpu_feature); |
239 | |
240 | module_init(crc32_pmull_mod_init); |
241 | module_exit(crc32_pmull_mod_exit); |
242 | |
243 | MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>" ); |
244 | MODULE_LICENSE("GPL v2" ); |
245 | MODULE_ALIAS_CRYPTO("crc32" ); |
246 | MODULE_ALIAS_CRYPTO("crc32c" ); |
247 | |