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 (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
 126 void 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 }
 138 EXPORT_SYMBOL(hchacha_block_arch);
 139
 140 void 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 }
 146 EXPORT_SYMBOL(chacha_init_arch);
 147
 148 void 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 }
 161 EXPORT_SYMBOL(chacha_crypt_arch);
 162
 163 static 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
 201 static 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
 209 static 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
 235 static 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
 284 static 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
 306 static 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
 312 module_init(chacha_simd_mod_init);
 313 module_exit(chacha_simd_mod_fini);
 314
 315 MODULE_LICENSE("GPL");
 316 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 317 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
 318 MODULE_ALIAS_CRYPTO("chacha20");
 319 MODULE_ALIAS_CRYPTO("chacha20-simd");
 320 MODULE_ALIAS_CRYPTO("xchacha20");
 321 MODULE_ALIAS_CRYPTO("xchacha20-simd");
 322 MODULE_ALIAS_CRYPTO("xchacha12");
 323 MODULE_ALIAS_CRYPTO("xchacha12-simd");