linux/arch/x86/crypto/chacha_glue.c
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   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 <linux/sizes.h>
  16#include <asm/simd.h>
  17
  18asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
  19                                       unsigned int len, int nrounds);
  20asmlinkage void chacha_4block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
  21                                        unsigned int len, int nrounds);
  22asmlinkage void hchacha_block_ssse3(const u32 *state, u32 *out, int nrounds);
  23
  24asmlinkage void chacha_2block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
  25                                       unsigned int len, int nrounds);
  26asmlinkage void chacha_4block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
  27                                       unsigned int len, int nrounds);
  28asmlinkage void chacha_8block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
  29                                       unsigned int len, int nrounds);
  30
  31asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
  32                                           unsigned int len, int nrounds);
  33asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
  34                                           unsigned int len, int nrounds);
  35asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
  36                                           unsigned int len, int nrounds);
  37
  38static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_simd);
  39static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx2);
  40static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx512vl);
  41
  42static unsigned int chacha_advance(unsigned int len, unsigned int maxblocks)
  43{
  44        len = min(len, maxblocks * CHACHA_BLOCK_SIZE);
  45        return round_up(len, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
  46}
  47
  48static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
  49                          unsigned int bytes, int nrounds)
  50{
  51        if (IS_ENABLED(CONFIG_AS_AVX512) &&
  52            static_branch_likely(&chacha_use_avx512vl)) {
  53                while (bytes >= CHACHA_BLOCK_SIZE * 8) {
  54                        chacha_8block_xor_avx512vl(state, dst, src, bytes,
  55                                                   nrounds);
  56                        bytes -= CHACHA_BLOCK_SIZE * 8;
  57                        src += CHACHA_BLOCK_SIZE * 8;
  58                        dst += CHACHA_BLOCK_SIZE * 8;
  59                        state[12] += 8;
  60                }
  61                if (bytes > CHACHA_BLOCK_SIZE * 4) {
  62                        chacha_8block_xor_avx512vl(state, dst, src, bytes,
  63                                                   nrounds);
  64                        state[12] += chacha_advance(bytes, 8);
  65                        return;
  66                }
  67                if (bytes > CHACHA_BLOCK_SIZE * 2) {
  68                        chacha_4block_xor_avx512vl(state, dst, src, bytes,
  69                                                   nrounds);
  70                        state[12] += chacha_advance(bytes, 4);
  71                        return;
  72                }
  73                if (bytes) {
  74                        chacha_2block_xor_avx512vl(state, dst, src, bytes,
  75                                                   nrounds);
  76                        state[12] += chacha_advance(bytes, 2);
  77                        return;
  78                }
  79        }
  80
  81        if (static_branch_likely(&chacha_use_avx2)) {
  82                while (bytes >= CHACHA_BLOCK_SIZE * 8) {
  83                        chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
  84                        bytes -= CHACHA_BLOCK_SIZE * 8;
  85                        src += CHACHA_BLOCK_SIZE * 8;
  86                        dst += CHACHA_BLOCK_SIZE * 8;
  87                        state[12] += 8;
  88                }
  89                if (bytes > CHACHA_BLOCK_SIZE * 4) {
  90                        chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
  91                        state[12] += chacha_advance(bytes, 8);
  92                        return;
  93                }
  94                if (bytes > CHACHA_BLOCK_SIZE * 2) {
  95                        chacha_4block_xor_avx2(state, dst, src, bytes, nrounds);
  96                        state[12] += chacha_advance(bytes, 4);
  97                        return;
  98                }
  99                if (bytes > CHACHA_BLOCK_SIZE) {
 100                        chacha_2block_xor_avx2(state, dst, src, bytes, nrounds);
 101                        state[12] += chacha_advance(bytes, 2);
 102                        return;
 103                }
 104        }
 105
 106        while (bytes >= CHACHA_BLOCK_SIZE * 4) {
 107                chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
 108                bytes -= CHACHA_BLOCK_SIZE * 4;
 109                src += CHACHA_BLOCK_SIZE * 4;
 110                dst += CHACHA_BLOCK_SIZE * 4;
 111                state[12] += 4;
 112        }
 113        if (bytes > CHACHA_BLOCK_SIZE) {
 114                chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
 115                state[12] += chacha_advance(bytes, 4);
 116                return;
 117        }
 118        if (bytes) {
 119                chacha_block_xor_ssse3(state, dst, src, bytes, nrounds);
 120                state[12]++;
 121        }
 122}
 123
 124void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
 125{
 126        if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable()) {
 127                hchacha_block_generic(state, stream, nrounds);
 128        } else {
 129                kernel_fpu_begin();
 130                hchacha_block_ssse3(state, stream, nrounds);
 131                kernel_fpu_end();
 132        }
 133}
 134EXPORT_SYMBOL(hchacha_block_arch);
 135
 136void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
 137{
 138        chacha_init_generic(state, key, iv);
 139}
 140EXPORT_SYMBOL(chacha_init_arch);
 141
 142void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
 143                       int nrounds)
 144{
 145        if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable() ||
 146            bytes <= CHACHA_BLOCK_SIZE)
 147                return chacha_crypt_generic(state, dst, src, bytes, nrounds);
 148
 149        do {
 150                unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
 151
 152                kernel_fpu_begin();
 153                chacha_dosimd(state, dst, src, todo, nrounds);
 154                kernel_fpu_end();
 155
 156                bytes -= todo;
 157                src += todo;
 158                dst += todo;
 159        } while (bytes);
 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[CHACHA_STATE_WORDS] __aligned(8);
 167        struct skcipher_walk walk;
 168        int err;
 169
 170        err = skcipher_walk_virt(&walk, req, false);
 171
 172        chacha_init_generic(state, ctx->key, iv);
 173
 174        while (walk.nbytes > 0) {
 175                unsigned int nbytes = walk.nbytes;
 176
 177                if (nbytes < walk.total)
 178                        nbytes = round_down(nbytes, walk.stride);
 179
 180                if (!static_branch_likely(&chacha_use_simd) ||
 181                    !crypto_simd_usable()) {
 182                        chacha_crypt_generic(state, walk.dst.virt.addr,
 183                                             walk.src.virt.addr, nbytes,
 184                                             ctx->nrounds);
 185                } else {
 186                        kernel_fpu_begin();
 187                        chacha_dosimd(state, walk.dst.virt.addr,
 188                                      walk.src.virt.addr, nbytes,
 189                                      ctx->nrounds);
 190                        kernel_fpu_end();
 191                }
 192                err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 193        }
 194
 195        return err;
 196}
 197
 198static int chacha_simd(struct skcipher_request *req)
 199{
 200        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 201        struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
 202
 203        return chacha_simd_stream_xor(req, ctx, req->iv);
 204}
 205
 206static int xchacha_simd(struct skcipher_request *req)
 207{
 208        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 209        struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
 210        u32 state[CHACHA_STATE_WORDS] __aligned(8);
 211        struct chacha_ctx subctx;
 212        u8 real_iv[16];
 213
 214        chacha_init_generic(state, ctx->key, req->iv);
 215
 216        if (req->cryptlen > CHACHA_BLOCK_SIZE && crypto_simd_usable()) {
 217                kernel_fpu_begin();
 218                hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
 219                kernel_fpu_end();
 220        } else {
 221                hchacha_block_generic(state, subctx.key, ctx->nrounds);
 222        }
 223        subctx.nrounds = ctx->nrounds;
 224
 225        memcpy(&real_iv[0], req->iv + 24, 8);
 226        memcpy(&real_iv[8], req->iv + 16, 8);
 227        return chacha_simd_stream_xor(req, &subctx, real_iv);
 228}
 229
 230static struct skcipher_alg algs[] = {
 231        {
 232                .base.cra_name          = "chacha20",
 233                .base.cra_driver_name   = "chacha20-simd",
 234                .base.cra_priority      = 300,
 235                .base.cra_blocksize     = 1,
 236                .base.cra_ctxsize       = sizeof(struct chacha_ctx),
 237                .base.cra_module        = THIS_MODULE,
 238
 239                .min_keysize            = CHACHA_KEY_SIZE,
 240                .max_keysize            = CHACHA_KEY_SIZE,
 241                .ivsize                 = CHACHA_IV_SIZE,
 242                .chunksize              = CHACHA_BLOCK_SIZE,
 243                .setkey                 = chacha20_setkey,
 244                .encrypt                = chacha_simd,
 245                .decrypt                = chacha_simd,
 246        }, {
 247                .base.cra_name          = "xchacha20",
 248                .base.cra_driver_name   = "xchacha20-simd",
 249                .base.cra_priority      = 300,
 250                .base.cra_blocksize     = 1,
 251                .base.cra_ctxsize       = sizeof(struct chacha_ctx),
 252                .base.cra_module        = THIS_MODULE,
 253
 254                .min_keysize            = CHACHA_KEY_SIZE,
 255                .max_keysize            = CHACHA_KEY_SIZE,
 256                .ivsize                 = XCHACHA_IV_SIZE,
 257                .chunksize              = CHACHA_BLOCK_SIZE,
 258                .setkey                 = chacha20_setkey,
 259                .encrypt                = xchacha_simd,
 260                .decrypt                = xchacha_simd,
 261        }, {
 262                .base.cra_name          = "xchacha12",
 263                .base.cra_driver_name   = "xchacha12-simd",
 264                .base.cra_priority      = 300,
 265                .base.cra_blocksize     = 1,
 266                .base.cra_ctxsize       = sizeof(struct chacha_ctx),
 267                .base.cra_module        = THIS_MODULE,
 268
 269                .min_keysize            = CHACHA_KEY_SIZE,
 270                .max_keysize            = CHACHA_KEY_SIZE,
 271                .ivsize                 = XCHACHA_IV_SIZE,
 272                .chunksize              = CHACHA_BLOCK_SIZE,
 273                .setkey                 = chacha12_setkey,
 274                .encrypt                = xchacha_simd,
 275                .decrypt                = xchacha_simd,
 276        },
 277};
 278
 279static int __init chacha_simd_mod_init(void)
 280{
 281        if (!boot_cpu_has(X86_FEATURE_SSSE3))
 282                return 0;
 283
 284        static_branch_enable(&chacha_use_simd);
 285
 286        if (boot_cpu_has(X86_FEATURE_AVX) &&
 287            boot_cpu_has(X86_FEATURE_AVX2) &&
 288            cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
 289                static_branch_enable(&chacha_use_avx2);
 290
 291                if (IS_ENABLED(CONFIG_AS_AVX512) &&
 292                    boot_cpu_has(X86_FEATURE_AVX512VL) &&
 293                    boot_cpu_has(X86_FEATURE_AVX512BW)) /* kmovq */
 294                        static_branch_enable(&chacha_use_avx512vl);
 295        }
 296        return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ?
 297                crypto_register_skciphers(algs, ARRAY_SIZE(algs)) : 0;
 298}
 299
 300static void __exit chacha_simd_mod_fini(void)
 301{
 302        if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) && boot_cpu_has(X86_FEATURE_SSSE3))
 303                crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
 304}
 305
 306module_init(chacha_simd_mod_init);
 307module_exit(chacha_simd_mod_fini);
 308
 309MODULE_LICENSE("GPL");
 310MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 311MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
 312MODULE_ALIAS_CRYPTO("chacha20");
 313MODULE_ALIAS_CRYPTO("chacha20-simd");
 314MODULE_ALIAS_CRYPTO("xchacha20");
 315MODULE_ALIAS_CRYPTO("xchacha20-simd");
 316MODULE_ALIAS_CRYPTO("xchacha12");
 317MODULE_ALIAS_CRYPTO("xchacha12-simd");
 318
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