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/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
  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 #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
 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
 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
 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
 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
 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");