1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * x64 SIMD accelerated ChaCha and XChaCha stream ciphers,
4 * including ChaCha20 (RFC7539)
5 *
6 * Copyright (C) 2015 Martin Willi
7 */
8
9 #include <crypto/algapi.h>
10 #include <crypto/internal/chacha.h>
11 #include <crypto/internal/simd.h>
12 #include <crypto/internal/skcipher.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/sizes.h>
16 #include <asm/simd.h>
17
18 asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
19 unsigned int len, int nrounds);
20 asmlinkage void chacha_4block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
21 unsigned int len, int nrounds);
22 asmlinkage void hchacha_block_ssse3(const u32 *state, u32 *out, int nrounds);
23
24 asmlinkage void chacha_2block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
25 unsigned int len, int nrounds);
26 asmlinkage void chacha_4block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
27 unsigned int len, int nrounds);
28 asmlinkage void chacha_8block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
29 unsigned int len, int nrounds);
30
31 asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
32 unsigned int len, int nrounds);
33 asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
34 unsigned int len, int nrounds);
35 asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
36 unsigned int len, int nrounds);
37
38 static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_simd);
39 static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx2);
40 static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx512vl);
41
chacha_advance(unsigned int len,unsigned int maxblocks)42 static unsigned int chacha_advance(unsigned int len, unsigned int maxblocks)
43 {
44 len = min(len, maxblocks * CHACHA_BLOCK_SIZE);
45 return round_up(len, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
46 }
47
chacha_dosimd(u32 * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)48 static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
49 unsigned int bytes, int nrounds)
50 {
51 if (IS_ENABLED(CONFIG_AS_AVX512) &&
52 static_branch_likely(&chacha_use_avx512vl)) {
53 while (bytes >= CHACHA_BLOCK_SIZE * 8) {
54 chacha_8block_xor_avx512vl(state, dst, src, bytes,
55 nrounds);
56 bytes -= CHACHA_BLOCK_SIZE * 8;
57 src += CHACHA_BLOCK_SIZE * 8;
58 dst += CHACHA_BLOCK_SIZE * 8;
59 state[12] += 8;
60 }
61 if (bytes > CHACHA_BLOCK_SIZE * 4) {
62 chacha_8block_xor_avx512vl(state, dst, src, bytes,
63 nrounds);
64 state[12] += chacha_advance(bytes, 8);
65 return;
66 }
67 if (bytes > CHACHA_BLOCK_SIZE * 2) {
68 chacha_4block_xor_avx512vl(state, dst, src, bytes,
69 nrounds);
70 state[12] += chacha_advance(bytes, 4);
71 return;
72 }
73 if (bytes) {
74 chacha_2block_xor_avx512vl(state, dst, src, bytes,
75 nrounds);
76 state[12] += chacha_advance(bytes, 2);
77 return;
78 }
79 }
80
81 if (static_branch_likely(&chacha_use_avx2)) {
82 while (bytes >= CHACHA_BLOCK_SIZE * 8) {
83 chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
84 bytes -= CHACHA_BLOCK_SIZE * 8;
85 src += CHACHA_BLOCK_SIZE * 8;
86 dst += CHACHA_BLOCK_SIZE * 8;
87 state[12] += 8;
88 }
89 if (bytes > CHACHA_BLOCK_SIZE * 4) {
90 chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
91 state[12] += chacha_advance(bytes, 8);
92 return;
93 }
94 if (bytes > CHACHA_BLOCK_SIZE * 2) {
95 chacha_4block_xor_avx2(state, dst, src, bytes, nrounds);
96 state[12] += chacha_advance(bytes, 4);
97 return;
98 }
99 if (bytes > CHACHA_BLOCK_SIZE) {
100 chacha_2block_xor_avx2(state, dst, src, bytes, nrounds);
101 state[12] += chacha_advance(bytes, 2);
102 return;
103 }
104 }
105
106 while (bytes >= CHACHA_BLOCK_SIZE * 4) {
107 chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
108 bytes -= CHACHA_BLOCK_SIZE * 4;
109 src += CHACHA_BLOCK_SIZE * 4;
110 dst += CHACHA_BLOCK_SIZE * 4;
111 state[12] += 4;
112 }
113 if (bytes > CHACHA_BLOCK_SIZE) {
114 chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
115 state[12] += chacha_advance(bytes, 4);
116 return;
117 }
118 if (bytes) {
119 chacha_block_xor_ssse3(state, dst, src, bytes, nrounds);
120 state[12]++;
121 }
122 }
123
hchacha_block_arch(const u32 * state,u32 * stream,int nrounds)124 void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
125 {
126 if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable()) {
127 hchacha_block_generic(state, stream, nrounds);
128 } else {
129 kernel_fpu_begin();
130 hchacha_block_ssse3(state, stream, nrounds);
131 kernel_fpu_end();
132 }
133 }
134 EXPORT_SYMBOL(hchacha_block_arch);
135
chacha_init_arch(u32 * state,const u32 * key,const u8 * iv)136 void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
137 {
138 chacha_init_generic(state, key, iv);
139 }
140 EXPORT_SYMBOL(chacha_init_arch);
141
chacha_crypt_arch(u32 * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)142 void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
143 int nrounds)
144 {
145 if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable() ||
146 bytes <= CHACHA_BLOCK_SIZE)
147 return chacha_crypt_generic(state, dst, src, bytes, nrounds);
148
149 do {
150 unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
151
152 kernel_fpu_begin();
153 chacha_dosimd(state, dst, src, todo, nrounds);
154 kernel_fpu_end();
155
156 bytes -= todo;
157 src += todo;
158 dst += todo;
159 } while (bytes);
160 }
161 EXPORT_SYMBOL(chacha_crypt_arch);
162
chacha_simd_stream_xor(struct skcipher_request * req,const struct chacha_ctx * ctx,const u8 * iv)163 static int chacha_simd_stream_xor(struct skcipher_request *req,
164 const struct chacha_ctx *ctx, const u8 *iv)
165 {
166 u32 state[CHACHA_STATE_WORDS] __aligned(8);
167 struct skcipher_walk walk;
168 int err;
169
170 err = skcipher_walk_virt(&walk, req, false);
171
172 chacha_init_generic(state, ctx->key, iv);
173
174 while (walk.nbytes > 0) {
175 unsigned int nbytes = walk.nbytes;
176
177 if (nbytes < walk.total)
178 nbytes = round_down(nbytes, walk.stride);
179
180 if (!static_branch_likely(&chacha_use_simd) ||
181 !crypto_simd_usable()) {
182 chacha_crypt_generic(state, walk.dst.virt.addr,
183 walk.src.virt.addr, nbytes,
184 ctx->nrounds);
185 } else {
186 kernel_fpu_begin();
187 chacha_dosimd(state, walk.dst.virt.addr,
188 walk.src.virt.addr, nbytes,
189 ctx->nrounds);
190 kernel_fpu_end();
191 }
192 err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
193 }
194
195 return err;
196 }
197
chacha_simd(struct skcipher_request * req)198 static int chacha_simd(struct skcipher_request *req)
199 {
200 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
201 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
202
203 return chacha_simd_stream_xor(req, ctx, req->iv);
204 }
205
xchacha_simd(struct skcipher_request * req)206 static int xchacha_simd(struct skcipher_request *req)
207 {
208 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
209 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
210 u32 state[CHACHA_STATE_WORDS] __aligned(8);
211 struct chacha_ctx subctx;
212 u8 real_iv[16];
213
214 chacha_init_generic(state, ctx->key, req->iv);
215
216 if (req->cryptlen > CHACHA_BLOCK_SIZE && crypto_simd_usable()) {
217 kernel_fpu_begin();
218 hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
219 kernel_fpu_end();
220 } else {
221 hchacha_block_generic(state, subctx.key, ctx->nrounds);
222 }
223 subctx.nrounds = ctx->nrounds;
224
225 memcpy(&real_iv[0], req->iv + 24, 8);
226 memcpy(&real_iv[8], req->iv + 16, 8);
227 return chacha_simd_stream_xor(req, &subctx, real_iv);
228 }
229
230 static struct skcipher_alg algs[] = {
231 {
232 .base.cra_name = "chacha20",
233 .base.cra_driver_name = "chacha20-simd",
234 .base.cra_priority = 300,
235 .base.cra_blocksize = 1,
236 .base.cra_ctxsize = sizeof(struct chacha_ctx),
237 .base.cra_module = THIS_MODULE,
238
239 .min_keysize = CHACHA_KEY_SIZE,
240 .max_keysize = CHACHA_KEY_SIZE,
241 .ivsize = CHACHA_IV_SIZE,
242 .chunksize = CHACHA_BLOCK_SIZE,
243 .setkey = chacha20_setkey,
244 .encrypt = chacha_simd,
245 .decrypt = chacha_simd,
246 }, {
247 .base.cra_name = "xchacha20",
248 .base.cra_driver_name = "xchacha20-simd",
249 .base.cra_priority = 300,
250 .base.cra_blocksize = 1,
251 .base.cra_ctxsize = sizeof(struct chacha_ctx),
252 .base.cra_module = THIS_MODULE,
253
254 .min_keysize = CHACHA_KEY_SIZE,
255 .max_keysize = CHACHA_KEY_SIZE,
256 .ivsize = XCHACHA_IV_SIZE,
257 .chunksize = CHACHA_BLOCK_SIZE,
258 .setkey = chacha20_setkey,
259 .encrypt = xchacha_simd,
260 .decrypt = xchacha_simd,
261 }, {
262 .base.cra_name = "xchacha12",
263 .base.cra_driver_name = "xchacha12-simd",
264 .base.cra_priority = 300,
265 .base.cra_blocksize = 1,
266 .base.cra_ctxsize = sizeof(struct chacha_ctx),
267 .base.cra_module = THIS_MODULE,
268
269 .min_keysize = CHACHA_KEY_SIZE,
270 .max_keysize = CHACHA_KEY_SIZE,
271 .ivsize = XCHACHA_IV_SIZE,
272 .chunksize = CHACHA_BLOCK_SIZE,
273 .setkey = chacha12_setkey,
274 .encrypt = xchacha_simd,
275 .decrypt = xchacha_simd,
276 },
277 };
278
chacha_simd_mod_init(void)279 static int __init chacha_simd_mod_init(void)
280 {
281 if (!boot_cpu_has(X86_FEATURE_SSSE3))
282 return 0;
283
284 static_branch_enable(&chacha_use_simd);
285
286 if (boot_cpu_has(X86_FEATURE_AVX) &&
287 boot_cpu_has(X86_FEATURE_AVX2) &&
288 cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
289 static_branch_enable(&chacha_use_avx2);
290
291 if (IS_ENABLED(CONFIG_AS_AVX512) &&
292 boot_cpu_has(X86_FEATURE_AVX512VL) &&
293 boot_cpu_has(X86_FEATURE_AVX512BW)) /* kmovq */
294 static_branch_enable(&chacha_use_avx512vl);
295 }
296 return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ?
297 crypto_register_skciphers(algs, ARRAY_SIZE(algs)) : 0;
298 }
299
chacha_simd_mod_fini(void)300 static void __exit chacha_simd_mod_fini(void)
301 {
302 if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) && boot_cpu_has(X86_FEATURE_SSSE3))
303 crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
304 }
305
306 module_init(chacha_simd_mod_init);
307 module_exit(chacha_simd_mod_fini);
308
309 MODULE_LICENSE("GPL");
310 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
311 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
312 MODULE_ALIAS_CRYPTO("chacha20");
313 MODULE_ALIAS_CRYPTO("chacha20-simd");
314 MODULE_ALIAS_CRYPTO("xchacha20");
315 MODULE_ALIAS_CRYPTO("xchacha20-simd");
316 MODULE_ALIAS_CRYPTO("xchacha12");
317 MODULE_ALIAS_CRYPTO("xchacha12-simd");
318