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/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
19 asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
20 unsigned int len, int nrounds);
21 asmlinkage void chacha_4block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
22 unsigned int len, int nrounds);
23 asmlinkage void hchacha_block_ssse3(const u32 *state, u32 *out, int nrounds);
24 #ifdef CONFIG_AS_AVX2
25 asmlinkage void chacha_2block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
26 unsigned int len, int nrounds);
27 asmlinkage void chacha_4block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
28 unsigned int len, int nrounds);
29 asmlinkage void chacha_8block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
30 unsigned int len, int nrounds);
31 static bool chacha_use_avx2;
32 #ifdef CONFIG_AS_AVX512
33 asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
34 unsigned int len, int nrounds);
35 asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
36 unsigned int len, int nrounds);
37 asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
38 unsigned int len, int nrounds);
39 static bool chacha_use_avx512vl;
40 #endif
41 #endif
42
chacha_advance(unsigned int len,unsigned int maxblocks)43 static 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
chacha_dosimd(u32 * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)49 static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
50 unsigned int bytes, int nrounds)
51 {
52 #ifdef CONFIG_AS_AVX2
53 #ifdef CONFIG_AS_AVX512
54 if (chacha_use_avx512vl) {
55 while (bytes >= CHACHA_BLOCK_SIZE * 8) {
56 chacha_8block_xor_avx512vl(state, dst, src, bytes,
57 nrounds);
58 bytes -= CHACHA_BLOCK_SIZE * 8;
59 src += CHACHA_BLOCK_SIZE * 8;
60 dst += CHACHA_BLOCK_SIZE * 8;
61 state[12] += 8;
62 }
63 if (bytes > CHACHA_BLOCK_SIZE * 4) {
64 chacha_8block_xor_avx512vl(state, dst, src, bytes,
65 nrounds);
66 state[12] += chacha_advance(bytes, 8);
67 return;
68 }
69 if (bytes > CHACHA_BLOCK_SIZE * 2) {
70 chacha_4block_xor_avx512vl(state, dst, src, bytes,
71 nrounds);
72 state[12] += chacha_advance(bytes, 4);
73 return;
74 }
75 if (bytes) {
76 chacha_2block_xor_avx512vl(state, dst, src, bytes,
77 nrounds);
78 state[12] += chacha_advance(bytes, 2);
79 return;
80 }
81 }
82 #endif
83 if (chacha_use_avx2) {
84 while (bytes >= CHACHA_BLOCK_SIZE * 8) {
85 chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
86 bytes -= CHACHA_BLOCK_SIZE * 8;
87 src += CHACHA_BLOCK_SIZE * 8;
88 dst += CHACHA_BLOCK_SIZE * 8;
89 state[12] += 8;
90 }
91 if (bytes > CHACHA_BLOCK_SIZE * 4) {
92 chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
93 state[12] += chacha_advance(bytes, 8);
94 return;
95 }
96 if (bytes > CHACHA_BLOCK_SIZE * 2) {
97 chacha_4block_xor_avx2(state, dst, src, bytes, nrounds);
98 state[12] += chacha_advance(bytes, 4);
99 return;
100 }
101 if (bytes > CHACHA_BLOCK_SIZE) {
102 chacha_2block_xor_avx2(state, dst, src, bytes, nrounds);
103 state[12] += chacha_advance(bytes, 2);
104 return;
105 }
106 }
107 #endif
108 while (bytes >= CHACHA_BLOCK_SIZE * 4) {
109 chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
110 bytes -= CHACHA_BLOCK_SIZE * 4;
111 src += CHACHA_BLOCK_SIZE * 4;
112 dst += CHACHA_BLOCK_SIZE * 4;
113 state[12] += 4;
114 }
115 if (bytes > CHACHA_BLOCK_SIZE) {
116 chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
117 state[12] += chacha_advance(bytes, 4);
118 return;
119 }
120 if (bytes) {
121 chacha_block_xor_ssse3(state, dst, src, bytes, nrounds);
122 state[12]++;
123 }
124 }
125
chacha_simd_stream_xor(struct skcipher_walk * walk,const struct chacha_ctx * ctx,const u8 * iv)126 static int chacha_simd_stream_xor(struct skcipher_walk *walk,
127 const struct chacha_ctx *ctx, const u8 *iv)
128 {
129 u32 *state, state_buf[16 + 2] __aligned(8);
130 int next_yield = 4096; /* bytes until next FPU yield */
131 int err = 0;
132
133 BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
134 state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
135
136 crypto_chacha_init(state, ctx, iv);
137
138 while (walk->nbytes > 0) {
139 unsigned int nbytes = walk->nbytes;
140
141 if (nbytes < walk->total) {
142 nbytes = round_down(nbytes, walk->stride);
143 next_yield -= nbytes;
144 }
145
146 chacha_dosimd(state, walk->dst.virt.addr, walk->src.virt.addr,
147 nbytes, ctx->nrounds);
148
149 if (next_yield <= 0) {
150 /* temporarily allow preemption */
151 kernel_fpu_end();
152 kernel_fpu_begin();
153 next_yield = 4096;
154 }
155
156 err = skcipher_walk_done(walk, walk->nbytes - nbytes);
157 }
158
159 return err;
160 }
161
chacha_simd(struct skcipher_request * req)162 static int chacha_simd(struct skcipher_request *req)
163 {
164 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
165 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
166 struct skcipher_walk walk;
167 int err;
168
169 if (req->cryptlen <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
170 return crypto_chacha_crypt(req);
171
172 err = skcipher_walk_virt(&walk, req, true);
173 if (err)
174 return err;
175
176 kernel_fpu_begin();
177 err = chacha_simd_stream_xor(&walk, ctx, req->iv);
178 kernel_fpu_end();
179 return err;
180 }
181
xchacha_simd(struct skcipher_request * req)182 static int xchacha_simd(struct skcipher_request *req)
183 {
184 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
185 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
186 struct skcipher_walk walk;
187 struct chacha_ctx subctx;
188 u32 *state, state_buf[16 + 2] __aligned(8);
189 u8 real_iv[16];
190 int err;
191
192 if (req->cryptlen <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
193 return crypto_xchacha_crypt(req);
194
195 err = skcipher_walk_virt(&walk, req, true);
196 if (err)
197 return err;
198
199 BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
200 state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
201 crypto_chacha_init(state, ctx, req->iv);
202
203 kernel_fpu_begin();
204
205 hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
206 subctx.nrounds = ctx->nrounds;
207
208 memcpy(&real_iv[0], req->iv + 24, 8);
209 memcpy(&real_iv[8], req->iv + 16, 8);
210 err = chacha_simd_stream_xor(&walk, &subctx, real_iv);
211
212 kernel_fpu_end();
213
214 return err;
215 }
216
217 static struct skcipher_alg algs[] = {
218 {
219 .base.cra_name = "chacha20",
220 .base.cra_driver_name = "chacha20-simd",
221 .base.cra_priority = 300,
222 .base.cra_blocksize = 1,
223 .base.cra_ctxsize = sizeof(struct chacha_ctx),
224 .base.cra_module = THIS_MODULE,
225
226 .min_keysize = CHACHA_KEY_SIZE,
227 .max_keysize = CHACHA_KEY_SIZE,
228 .ivsize = CHACHA_IV_SIZE,
229 .chunksize = CHACHA_BLOCK_SIZE,
230 .setkey = crypto_chacha20_setkey,
231 .encrypt = chacha_simd,
232 .decrypt = chacha_simd,
233 }, {
234 .base.cra_name = "xchacha20",
235 .base.cra_driver_name = "xchacha20-simd",
236 .base.cra_priority = 300,
237 .base.cra_blocksize = 1,
238 .base.cra_ctxsize = sizeof(struct chacha_ctx),
239 .base.cra_module = THIS_MODULE,
240
241 .min_keysize = CHACHA_KEY_SIZE,
242 .max_keysize = CHACHA_KEY_SIZE,
243 .ivsize = XCHACHA_IV_SIZE,
244 .chunksize = CHACHA_BLOCK_SIZE,
245 .setkey = crypto_chacha20_setkey,
246 .encrypt = xchacha_simd,
247 .decrypt = xchacha_simd,
248 }, {
249 .base.cra_name = "xchacha12",
250 .base.cra_driver_name = "xchacha12-simd",
251 .base.cra_priority = 300,
252 .base.cra_blocksize = 1,
253 .base.cra_ctxsize = sizeof(struct chacha_ctx),
254 .base.cra_module = THIS_MODULE,
255
256 .min_keysize = CHACHA_KEY_SIZE,
257 .max_keysize = CHACHA_KEY_SIZE,
258 .ivsize = XCHACHA_IV_SIZE,
259 .chunksize = CHACHA_BLOCK_SIZE,
260 .setkey = crypto_chacha12_setkey,
261 .encrypt = xchacha_simd,
262 .decrypt = xchacha_simd,
263 },
264 };
265
chacha_simd_mod_init(void)266 static int __init chacha_simd_mod_init(void)
267 {
268 if (!boot_cpu_has(X86_FEATURE_SSSE3))
269 return -ENODEV;
270
271 #ifdef CONFIG_AS_AVX2
272 chacha_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
273 boot_cpu_has(X86_FEATURE_AVX2) &&
274 cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
275 #ifdef CONFIG_AS_AVX512
276 chacha_use_avx512vl = chacha_use_avx2 &&
277 boot_cpu_has(X86_FEATURE_AVX512VL) &&
278 boot_cpu_has(X86_FEATURE_AVX512BW); /* kmovq */
279 #endif
280 #endif
281 return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
282 }
283
chacha_simd_mod_fini(void)284 static void __exit chacha_simd_mod_fini(void)
285 {
286 crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
287 }
288
289 module_init(chacha_simd_mod_init);
290 module_exit(chacha_simd_mod_fini);
291
292 MODULE_LICENSE("GPL");
293 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
294 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
295 MODULE_ALIAS_CRYPTO("chacha20");
296 MODULE_ALIAS_CRYPTO("chacha20-simd");
297 MODULE_ALIAS_CRYPTO("xchacha20");
298 MODULE_ALIAS_CRYPTO("xchacha20-simd");
299 MODULE_ALIAS_CRYPTO("xchacha12");
300 MODULE_ALIAS_CRYPTO("xchacha12-simd");
301
