arch/arm/crypto/chacha-neon-glue.c

   1 /*
   2  * ARM NEON accelerated ChaCha and XChaCha stream ciphers,
   3  * including ChaCha20 (RFC7539)
   4  *
   5  * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel@linaro.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Based on:
  12  * ChaCha20 256-bit cipher algorithm, RFC7539, SIMD glue code
  13  *
  14  * Copyright (C) 2015 Martin Willi
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 2 of the License, or
  19  * (at your option) any later version.
  20  */
  21
  22 #include <crypto/algapi.h>
  23 #include <crypto/chacha.h>
  24 #include <crypto/internal/skcipher.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27
  28 #include <asm/hwcap.h>
  29 #include <asm/neon.h>
  30 #include <asm/simd.h>
  31
  32 asmlinkage void chacha_block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
  33                                       int nrounds);
  34 asmlinkage void chacha_4block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
  35                                        int nrounds);
  36 asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);
  37
  38 static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
  39                           unsigned int bytes, int nrounds)
  40 {
  41         u8 buf[CHACHA_BLOCK_SIZE];
  42
  43         while (bytes >= CHACHA_BLOCK_SIZE * 4) {
  44                 chacha_4block_xor_neon(state, dst, src, nrounds);
  45                 bytes -= CHACHA_BLOCK_SIZE * 4;
  46                 src += CHACHA_BLOCK_SIZE * 4;
  47                 dst += CHACHA_BLOCK_SIZE * 4;
  48                 state[12] += 4;
  49         }
  50         while (bytes >= CHACHA_BLOCK_SIZE) {
  51                 chacha_block_xor_neon(state, dst, src, nrounds);
  52                 bytes -= CHACHA_BLOCK_SIZE;
  53                 src += CHACHA_BLOCK_SIZE;
  54                 dst += CHACHA_BLOCK_SIZE;
  55                 state[12]++;
  56         }
  57         if (bytes) {
  58                 memcpy(buf, src, bytes);
  59                 chacha_block_xor_neon(state, buf, buf, nrounds);
  60                 memcpy(dst, buf, bytes);
  61         }
  62 }
  63
  64 static int chacha_neon_stream_xor(struct skcipher_request *req,
  65                                   struct chacha_ctx *ctx, u8 *iv)
  66 {
  67         struct skcipher_walk walk;
  68         u32 state[16];
  69         int err;
  70
  71         err = skcipher_walk_virt(&walk, req, false);
  72
  73         crypto_chacha_init(state, ctx, iv);
  74
  75         while (walk.nbytes > 0) {
  76                 unsigned int nbytes = walk.nbytes;
  77
  78                 if (nbytes < walk.total)
  79                         nbytes = round_down(nbytes, walk.stride);
  80
  81                 kernel_neon_begin();
  82                 chacha_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
  83                               nbytes, ctx->nrounds);
  84                 kernel_neon_end();
  85                 err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
  86         }
  87
  88         return err;
  89 }
  90
  91 static int chacha_neon(struct skcipher_request *req)
  92 {
  93         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  94         struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
  95
  96         if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
  97                 return crypto_chacha_crypt(req);
  98
  99         return chacha_neon_stream_xor(req, ctx, req->iv);
 100 }
 101
 102 static int xchacha_neon(struct skcipher_request *req)
 103 {
 104         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 105         struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
 106         struct chacha_ctx subctx;
 107         u32 state[16];
 108         u8 real_iv[16];
 109
 110         if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
 111                 return crypto_xchacha_crypt(req);
 112
 113         crypto_chacha_init(state, ctx, req->iv);
 114
 115         kernel_neon_begin();
 116         hchacha_block_neon(state, subctx.key, ctx->nrounds);
 117         kernel_neon_end();
 118         subctx.nrounds = ctx->nrounds;
 119
 120         memcpy(&real_iv[0], req->iv + 24, 8);
 121         memcpy(&real_iv[8], req->iv + 16, 8);
 122         return chacha_neon_stream_xor(req, &subctx, real_iv);
 123 }
 124
 125 static struct skcipher_alg algs[] = {
 126         {
 127                 .base.cra_name          = "chacha20",
 128                 .base.cra_driver_name   = "chacha20-neon",
 129                 .base.cra_priority      = 300,
 130                 .base.cra_blocksize     = 1,
 131                 .base.cra_ctxsize       = sizeof(struct chacha_ctx),
 132                 .base.cra_module        = THIS_MODULE,
 133
 134                 .min_keysize            = CHACHA_KEY_SIZE,
 135                 .max_keysize            = CHACHA_KEY_SIZE,
 136                 .ivsize                 = CHACHA_IV_SIZE,
 137                 .chunksize              = CHACHA_BLOCK_SIZE,
 138                 .walksize               = 4 * CHACHA_BLOCK_SIZE,
 139                 .setkey                 = crypto_chacha20_setkey,
 140                 .encrypt                = chacha_neon,
 141                 .decrypt                = chacha_neon,
 142         }, {
 143                 .base.cra_name          = "xchacha20",
 144                 .base.cra_driver_name   = "xchacha20-neon",
 145                 .base.cra_priority      = 300,
 146                 .base.cra_blocksize     = 1,
 147                 .base.cra_ctxsize       = sizeof(struct chacha_ctx),
 148                 .base.cra_module        = THIS_MODULE,
 149
 150                 .min_keysize            = CHACHA_KEY_SIZE,
 151                 .max_keysize            = CHACHA_KEY_SIZE,
 152                 .ivsize                 = XCHACHA_IV_SIZE,
 153                 .chunksize              = CHACHA_BLOCK_SIZE,
 154                 .walksize               = 4 * CHACHA_BLOCK_SIZE,
 155                 .setkey                 = crypto_chacha20_setkey,
 156                 .encrypt                = xchacha_neon,
 157                 .decrypt                = xchacha_neon,
 158         }, {
 159                 .base.cra_name          = "xchacha12",
 160                 .base.cra_driver_name   = "xchacha12-neon",
 161                 .base.cra_priority      = 300,
 162                 .base.cra_blocksize     = 1,
 163                 .base.cra_ctxsize       = sizeof(struct chacha_ctx),
 164                 .base.cra_module        = THIS_MODULE,
 165
 166                 .min_keysize            = CHACHA_KEY_SIZE,
 167                 .max_keysize            = CHACHA_KEY_SIZE,
 168                 .ivsize                 = XCHACHA_IV_SIZE,
 169                 .chunksize              = CHACHA_BLOCK_SIZE,
 170                 .walksize               = 4 * CHACHA_BLOCK_SIZE,
 171                 .setkey                 = crypto_chacha12_setkey,
 172                 .encrypt                = xchacha_neon,
 173                 .decrypt                = xchacha_neon,
 174         }
 175 };
 176
 177 static int __init chacha_simd_mod_init(void)
 178 {
 179         if (!(elf_hwcap & HWCAP_NEON))
 180                 return -ENODEV;
 181
 182         return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
 183 }
 184
 185 static void __exit chacha_simd_mod_fini(void)
 186 {
 187         crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
 188 }
 189
 190 module_init(chacha_simd_mod_init);
 191 module_exit(chacha_simd_mod_fini);
 192
 193 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (NEON accelerated)");
 194 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 195 MODULE_LICENSE("GPL v2");
 196 MODULE_ALIAS_CRYPTO("chacha20");
 197 MODULE_ALIAS_CRYPTO("chacha20-neon");
 198 MODULE_ALIAS_CRYPTO("xchacha20");
 199 MODULE_ALIAS_CRYPTO("xchacha20-neon");
 200 MODULE_ALIAS_CRYPTO("xchacha12");
 201 MODULE_ALIAS_CRYPTO("xchacha12-neon");