arch/x86/crypto/chacha_glue.c

   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
  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
  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
  32 asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
  33                                            unsigned int len, int nrounds);
  34 asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
  35                                            unsigned int len, int nrounds);
  36 asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
  37                                            unsigned int len, int nrounds);
  38
  39 static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_simd);
  40 static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx2);
  41 static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx512vl);
  42
  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
  49 static 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
 125 void 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 }
 137 EXPORT_SYMBOL(hchacha_block_arch);
 138
 139 void 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 }
 145 EXPORT_SYMBOL(chacha_init_arch);
 146
 147 void 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 }
 168 EXPORT_SYMBOL(chacha_crypt_arch);
 169
 170 static 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
 208 static 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
 216 static 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
 242 static 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
 291 static 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
 312 static 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
 318 module_init(chacha_simd_mod_init);
 319 module_exit(chacha_simd_mod_fini);
 320
 321 MODULE_LICENSE("GPL");
 322 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 323 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
 324 MODULE_ALIAS_CRYPTO("chacha20");
 325 MODULE_ALIAS_CRYPTO("chacha20-simd");
 326 MODULE_ALIAS_CRYPTO("xchacha20");
 327 MODULE_ALIAS_CRYPTO("xchacha20-simd");
 328 MODULE_ALIAS_CRYPTO("xchacha12");
 329 MODULE_ALIAS_CRYPTO("xchacha12-simd");