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Linux kernel mirror (for testing)
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linux
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 <asm/simd.h>
16
17#define CHACHA_STATE_ALIGN 16
18
19asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
20 unsigned int len, int nrounds);
21asmlinkage void chacha_4block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
22 unsigned int len, int nrounds);
23asmlinkage void hchacha_block_ssse3(const u32 *state, u32 *out, int nrounds);
24
25asmlinkage void chacha_2block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
26 unsigned int len, int nrounds);
27asmlinkage void chacha_4block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
28 unsigned int len, int nrounds);
29asmlinkage void chacha_8block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
30 unsigned int len, int nrounds);
31
32asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
33 unsigned int len, int nrounds);
34asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
35 unsigned int len, int nrounds);
36asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
37 unsigned int len, int nrounds);
38
39static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_simd);
40static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx2);
41static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx512vl);
42
43static unsigned int chacha_advance(unsigned int len, unsigned int maxblocks)
44{
45 len = min(len, maxblocks * CHACHA_BLOCK_SIZE);
46 return round_up(len, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
47}
48
49static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
50 unsigned int bytes, int nrounds)
51{
52 if (IS_ENABLED(CONFIG_AS_AVX512) &&
53 static_branch_likely(&chacha_use_avx512vl)) {
54 while (bytes >= CHACHA_BLOCK_SIZE * 8) {
55 chacha_8block_xor_avx512vl(state, dst, src, bytes,
56 nrounds);
57 bytes -= CHACHA_BLOCK_SIZE * 8;
58 src += CHACHA_BLOCK_SIZE * 8;
59 dst += CHACHA_BLOCK_SIZE * 8;
60 state[12] += 8;
61 }
62 if (bytes > CHACHA_BLOCK_SIZE * 4) {
63 chacha_8block_xor_avx512vl(state, dst, src, bytes,
64 nrounds);
65 state[12] += chacha_advance(bytes, 8);
66 return;
67 }
68 if (bytes > CHACHA_BLOCK_SIZE * 2) {
69 chacha_4block_xor_avx512vl(state, dst, src, bytes,
70 nrounds);
71 state[12] += chacha_advance(bytes, 4);
72 return;
73 }
74 if (bytes) {
75 chacha_2block_xor_avx512vl(state, dst, src, bytes,
76 nrounds);
77 state[12] += chacha_advance(bytes, 2);
78 return;
79 }
80 }
81
82 if (static_branch_likely(&chacha_use_avx2)) {
83 while (bytes >= CHACHA_BLOCK_SIZE * 8) {
84 chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
85 bytes -= CHACHA_BLOCK_SIZE * 8;
86 src += CHACHA_BLOCK_SIZE * 8;
87 dst += CHACHA_BLOCK_SIZE * 8;
88 state[12] += 8;
89 }
90 if (bytes > CHACHA_BLOCK_SIZE * 4) {
91 chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
92 state[12] += chacha_advance(bytes, 8);
93 return;
94 }
95 if (bytes > CHACHA_BLOCK_SIZE * 2) {
96 chacha_4block_xor_avx2(state, dst, src, bytes, nrounds);
97 state[12] += chacha_advance(bytes, 4);
98 return;
99 }
100 if (bytes > CHACHA_BLOCK_SIZE) {
101 chacha_2block_xor_avx2(state, dst, src, bytes, nrounds);
102 state[12] += chacha_advance(bytes, 2);
103 return;
104 }
105 }
106
107 while (bytes >= CHACHA_BLOCK_SIZE * 4) {
108 chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
109 bytes -= CHACHA_BLOCK_SIZE * 4;
110 src += CHACHA_BLOCK_SIZE * 4;
111 dst += CHACHA_BLOCK_SIZE * 4;
112 state[12] += 4;
113 }
114 if (bytes > CHACHA_BLOCK_SIZE) {
115 chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
116 state[12] += chacha_advance(bytes, 4);
117 return;
118 }
119 if (bytes) {
120 chacha_block_xor_ssse3(state, dst, src, bytes, nrounds);
121 state[12]++;
122 }
123}
124
125void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
126{
127 state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
128
129 if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable()) {
130 hchacha_block_generic(state, stream, nrounds);
131 } else {
132 kernel_fpu_begin();
133 hchacha_block_ssse3(state, stream, nrounds);
134 kernel_fpu_end();
135 }
136}
137EXPORT_SYMBOL(hchacha_block_arch);
138
139void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
140{
141 state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
142
143 chacha_init_generic(state, key, iv);
144}
145EXPORT_SYMBOL(chacha_init_arch);
146
147void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
148 int nrounds)
149{
150 state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
151
152 if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable() ||
153 bytes <= CHACHA_BLOCK_SIZE)
154 return chacha_crypt_generic(state, dst, src, bytes, nrounds);
155
156 do {
157 unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
158
159 kernel_fpu_begin();
160 chacha_dosimd(state, dst, src, todo, nrounds);
161 kernel_fpu_end();
162
163 bytes -= todo;
164 src += todo;
165 dst += todo;
166 } while (bytes);
167}
168EXPORT_SYMBOL(chacha_crypt_arch);
169
170static int chacha_simd_stream_xor(struct skcipher_request *req,
171 const struct chacha_ctx *ctx, const u8 *iv)
172{
173 u32 *state, state_buf[16 + 2] __aligned(8);
174 struct skcipher_walk walk;
175 int err;
176
177 err = skcipher_walk_virt(&walk, req, false);
178
179 BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
180 state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
181
182 chacha_init_generic(state, ctx->key, iv);
183
184 while (walk.nbytes > 0) {
185 unsigned int nbytes = walk.nbytes;
186
187 if (nbytes < walk.total)
188 nbytes = round_down(nbytes, walk.stride);
189
190 if (!static_branch_likely(&chacha_use_simd) ||
191 !crypto_simd_usable()) {
192 chacha_crypt_generic(state, walk.dst.virt.addr,
193 walk.src.virt.addr, nbytes,
194 ctx->nrounds);
195 } else {
196 kernel_fpu_begin();
197 chacha_dosimd(state, walk.dst.virt.addr,
198 walk.src.virt.addr, nbytes,
199 ctx->nrounds);
200 kernel_fpu_end();
201 }
202 err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
203 }
204
205 return err;
206}
207
208static int chacha_simd(struct skcipher_request *req)
209{
210 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
211 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
212
213 return chacha_simd_stream_xor(req, ctx, req->iv);
214}
215
216static int xchacha_simd(struct skcipher_request *req)
217{
218 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
219 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
220 u32 *state, state_buf[16 + 2] __aligned(8);
221 struct chacha_ctx subctx;
222 u8 real_iv[16];
223
224 BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
225 state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
226 chacha_init_generic(state, ctx->key, req->iv);
227
228 if (req->cryptlen > CHACHA_BLOCK_SIZE && crypto_simd_usable()) {
229 kernel_fpu_begin();
230 hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
231 kernel_fpu_end();
232 } else {
233 hchacha_block_generic(state, subctx.key, ctx->nrounds);
234 }
235 subctx.nrounds = ctx->nrounds;
236
237 memcpy(&real_iv[0], req->iv + 24, 8);
238 memcpy(&real_iv[8], req->iv + 16, 8);
239 return chacha_simd_stream_xor(req, &subctx, real_iv);
240}
241
242static struct skcipher_alg algs[] = {
243 {
244 .base.cra_name = "chacha20",
245 .base.cra_driver_name = "chacha20-simd",
246 .base.cra_priority = 300,
247 .base.cra_blocksize = 1,
248 .base.cra_ctxsize = sizeof(struct chacha_ctx),
249 .base.cra_module = THIS_MODULE,
250
251 .min_keysize = CHACHA_KEY_SIZE,
252 .max_keysize = CHACHA_KEY_SIZE,
253 .ivsize = CHACHA_IV_SIZE,
254 .chunksize = CHACHA_BLOCK_SIZE,
255 .setkey = chacha20_setkey,
256 .encrypt = chacha_simd,
257 .decrypt = chacha_simd,
258 }, {
259 .base.cra_name = "xchacha20",
260 .base.cra_driver_name = "xchacha20-simd",
261 .base.cra_priority = 300,
262 .base.cra_blocksize = 1,
263 .base.cra_ctxsize = sizeof(struct chacha_ctx),
264 .base.cra_module = THIS_MODULE,
265
266 .min_keysize = CHACHA_KEY_SIZE,
267 .max_keysize = CHACHA_KEY_SIZE,
268 .ivsize = XCHACHA_IV_SIZE,
269 .chunksize = CHACHA_BLOCK_SIZE,
270 .setkey = chacha20_setkey,
271 .encrypt = xchacha_simd,
272 .decrypt = xchacha_simd,
273 }, {
274 .base.cra_name = "xchacha12",
275 .base.cra_driver_name = "xchacha12-simd",
276 .base.cra_priority = 300,
277 .base.cra_blocksize = 1,
278 .base.cra_ctxsize = sizeof(struct chacha_ctx),
279 .base.cra_module = THIS_MODULE,
280
281 .min_keysize = CHACHA_KEY_SIZE,
282 .max_keysize = CHACHA_KEY_SIZE,
283 .ivsize = XCHACHA_IV_SIZE,
284 .chunksize = CHACHA_BLOCK_SIZE,
285 .setkey = chacha12_setkey,
286 .encrypt = xchacha_simd,
287 .decrypt = xchacha_simd,
288 },
289};
290
291static int __init chacha_simd_mod_init(void)
292{
293 if (!boot_cpu_has(X86_FEATURE_SSSE3))
294 return 0;
295
296 static_branch_enable(&chacha_use_simd);
297
298 if (boot_cpu_has(X86_FEATURE_AVX) &&
299 boot_cpu_has(X86_FEATURE_AVX2) &&
300 cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
301 static_branch_enable(&chacha_use_avx2);
302
303 if (IS_ENABLED(CONFIG_AS_AVX512) &&
304 boot_cpu_has(X86_FEATURE_AVX512VL) &&
305 boot_cpu_has(X86_FEATURE_AVX512BW)) /* kmovq */
306 static_branch_enable(&chacha_use_avx512vl);
307 }
308 return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ?
309 crypto_register_skciphers(algs, ARRAY_SIZE(algs)) : 0;
310}
311
312static void __exit chacha_simd_mod_fini(void)
313{
314 if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) && boot_cpu_has(X86_FEATURE_SSSE3))
315 crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
316}
317
318module_init(chacha_simd_mod_init);
319module_exit(chacha_simd_mod_fini);
320
321MODULE_LICENSE("GPL");
322MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
323MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
324MODULE_ALIAS_CRYPTO("chacha20");
325MODULE_ALIAS_CRYPTO("chacha20-simd");
326MODULE_ALIAS_CRYPTO("xchacha20");
327MODULE_ALIAS_CRYPTO("xchacha20-simd");
328MODULE_ALIAS_CRYPTO("xchacha12");
329MODULE_ALIAS_CRYPTO("xchacha12-simd");