tjh.dev
Linux kernel mirror (for testing)
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kernel
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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 (IS_ENABLED(CONFIG_AS_AVX2) &&
83 static_branch_likely(&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
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
126void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
127{
128 state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
129
130 if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable()) {
131 hchacha_block_generic(state, stream, nrounds);
132 } else {
133 kernel_fpu_begin();
134 hchacha_block_ssse3(state, stream, nrounds);
135 kernel_fpu_end();
136 }
137}
138EXPORT_SYMBOL(hchacha_block_arch);
139
140void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
141{
142 state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
143
144 chacha_init_generic(state, key, iv);
145}
146EXPORT_SYMBOL(chacha_init_arch);
147
148void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
149 int nrounds)
150{
151 state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
152
153 if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable() ||
154 bytes <= CHACHA_BLOCK_SIZE)
155 return chacha_crypt_generic(state, dst, src, bytes, nrounds);
156
157 kernel_fpu_begin();
158 chacha_dosimd(state, dst, src, bytes, nrounds);
159 kernel_fpu_end();
160}
161EXPORT_SYMBOL(chacha_crypt_arch);
162
163static int chacha_simd_stream_xor(struct skcipher_request *req,
164 const struct chacha_ctx *ctx, const u8 *iv)
165{
166 u32 *state, state_buf[16 + 2] __aligned(8);
167 struct skcipher_walk walk;
168 int err;
169
170 err = skcipher_walk_virt(&walk, req, false);
171
172 BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
173 state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
174
175 chacha_init_generic(state, ctx->key, iv);
176
177 while (walk.nbytes > 0) {
178 unsigned int nbytes = walk.nbytes;
179
180 if (nbytes < walk.total)
181 nbytes = round_down(nbytes, walk.stride);
182
183 if (!static_branch_likely(&chacha_use_simd) ||
184 !crypto_simd_usable()) {
185 chacha_crypt_generic(state, walk.dst.virt.addr,
186 walk.src.virt.addr, nbytes,
187 ctx->nrounds);
188 } else {
189 kernel_fpu_begin();
190 chacha_dosimd(state, walk.dst.virt.addr,
191 walk.src.virt.addr, nbytes,
192 ctx->nrounds);
193 kernel_fpu_end();
194 }
195 err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
196 }
197
198 return err;
199}
200
201static int chacha_simd(struct skcipher_request *req)
202{
203 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
204 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
205
206 return chacha_simd_stream_xor(req, ctx, req->iv);
207}
208
209static int xchacha_simd(struct skcipher_request *req)
210{
211 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
212 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
213 u32 *state, state_buf[16 + 2] __aligned(8);
214 struct chacha_ctx subctx;
215 u8 real_iv[16];
216
217 BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
218 state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
219 chacha_init_generic(state, ctx->key, req->iv);
220
221 if (req->cryptlen > CHACHA_BLOCK_SIZE && crypto_simd_usable()) {
222 kernel_fpu_begin();
223 hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
224 kernel_fpu_end();
225 } else {
226 hchacha_block_generic(state, subctx.key, ctx->nrounds);
227 }
228 subctx.nrounds = ctx->nrounds;
229
230 memcpy(&real_iv[0], req->iv + 24, 8);
231 memcpy(&real_iv[8], req->iv + 16, 8);
232 return chacha_simd_stream_xor(req, &subctx, real_iv);
233}
234
235static struct skcipher_alg algs[] = {
236 {
237 .base.cra_name = "chacha20",
238 .base.cra_driver_name = "chacha20-simd",
239 .base.cra_priority = 300,
240 .base.cra_blocksize = 1,
241 .base.cra_ctxsize = sizeof(struct chacha_ctx),
242 .base.cra_module = THIS_MODULE,
243
244 .min_keysize = CHACHA_KEY_SIZE,
245 .max_keysize = CHACHA_KEY_SIZE,
246 .ivsize = CHACHA_IV_SIZE,
247 .chunksize = CHACHA_BLOCK_SIZE,
248 .setkey = chacha20_setkey,
249 .encrypt = chacha_simd,
250 .decrypt = chacha_simd,
251 }, {
252 .base.cra_name = "xchacha20",
253 .base.cra_driver_name = "xchacha20-simd",
254 .base.cra_priority = 300,
255 .base.cra_blocksize = 1,
256 .base.cra_ctxsize = sizeof(struct chacha_ctx),
257 .base.cra_module = THIS_MODULE,
258
259 .min_keysize = CHACHA_KEY_SIZE,
260 .max_keysize = CHACHA_KEY_SIZE,
261 .ivsize = XCHACHA_IV_SIZE,
262 .chunksize = CHACHA_BLOCK_SIZE,
263 .setkey = chacha20_setkey,
264 .encrypt = xchacha_simd,
265 .decrypt = xchacha_simd,
266 }, {
267 .base.cra_name = "xchacha12",
268 .base.cra_driver_name = "xchacha12-simd",
269 .base.cra_priority = 300,
270 .base.cra_blocksize = 1,
271 .base.cra_ctxsize = sizeof(struct chacha_ctx),
272 .base.cra_module = THIS_MODULE,
273
274 .min_keysize = CHACHA_KEY_SIZE,
275 .max_keysize = CHACHA_KEY_SIZE,
276 .ivsize = XCHACHA_IV_SIZE,
277 .chunksize = CHACHA_BLOCK_SIZE,
278 .setkey = chacha12_setkey,
279 .encrypt = xchacha_simd,
280 .decrypt = xchacha_simd,
281 },
282};
283
284static int __init chacha_simd_mod_init(void)
285{
286 if (!boot_cpu_has(X86_FEATURE_SSSE3))
287 return 0;
288
289 static_branch_enable(&chacha_use_simd);
290
291 if (IS_ENABLED(CONFIG_AS_AVX2) &&
292 boot_cpu_has(X86_FEATURE_AVX) &&
293 boot_cpu_has(X86_FEATURE_AVX2) &&
294 cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
295 static_branch_enable(&chacha_use_avx2);
296
297 if (IS_ENABLED(CONFIG_AS_AVX512) &&
298 boot_cpu_has(X86_FEATURE_AVX512VL) &&
299 boot_cpu_has(X86_FEATURE_AVX512BW)) /* kmovq */
300 static_branch_enable(&chacha_use_avx512vl);
301 }
302 return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ?
303 crypto_register_skciphers(algs, ARRAY_SIZE(algs)) : 0;
304}
305
306static void __exit chacha_simd_mod_fini(void)
307{
308 if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) && boot_cpu_has(X86_FEATURE_SSSE3))
309 crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
310}
311
312module_init(chacha_simd_mod_init);
313module_exit(chacha_simd_mod_fini);
314
315MODULE_LICENSE("GPL");
316MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
317MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
318MODULE_ALIAS_CRYPTO("chacha20");
319MODULE_ALIAS_CRYPTO("chacha20-simd");
320MODULE_ALIAS_CRYPTO("xchacha20");
321MODULE_ALIAS_CRYPTO("xchacha20-simd");
322MODULE_ALIAS_CRYPTO("xchacha12");
323MODULE_ALIAS_CRYPTO("xchacha12-simd");