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