arch/arm64/crypto/aes-ce-cipher.c

   1 /*
   2  * aes-ce-cipher.c - core AES cipher using ARMv8 Crypto Extensions
   3  *
   4  * Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <asm/neon.h>
  12 #include <crypto/aes.h>
  13 #include <linux/cpufeature.h>
  14 #include <linux/crypto.h>
  15 #include <linux/module.h>
  16
  17 MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
  18 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  19 MODULE_LICENSE("GPL v2");
  20
  21 struct aes_block {
  22         u8 b[AES_BLOCK_SIZE];
  23 };
  24
  25 static int num_rounds(struct crypto_aes_ctx *ctx)
  26 {
  27         /*
  28          * # of rounds specified by AES:
  29          * 128 bit key          10 rounds
  30          * 192 bit key          12 rounds
  31          * 256 bit key          14 rounds
  32          * => n byte key        => 6 + (n/4) rounds
  33          */
  34         return 6 + ctx->key_length / 4;
  35 }
  36
  37 static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
  38 {
  39         struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  40         struct aes_block *out = (struct aes_block *)dst;
  41         struct aes_block const *in = (struct aes_block *)src;
  42         void *dummy0;
  43         int dummy1;
  44
  45         kernel_neon_begin_partial(4);
  46
  47         __asm__("       ld1     {v0.16b}, %[in]                 ;"
  48                 "       ld1     {v1.2d}, [%[key]], #16          ;"
  49                 "       cmp     %w[rounds], #10                 ;"
  50                 "       bmi     0f                              ;"
  51                 "       bne     3f                              ;"
  52                 "       mov     v3.16b, v1.16b                  ;"
  53                 "       b       2f                              ;"
  54                 "0:     mov     v2.16b, v1.16b                  ;"
  55                 "       ld1     {v3.2d}, [%[key]], #16          ;"
  56                 "1:     aese    v0.16b, v2.16b                  ;"
  57                 "       aesmc   v0.16b, v0.16b                  ;"
  58                 "2:     ld1     {v1.2d}, [%[key]], #16          ;"
  59                 "       aese    v0.16b, v3.16b                  ;"
  60                 "       aesmc   v0.16b, v0.16b                  ;"
  61                 "3:     ld1     {v2.2d}, [%[key]], #16          ;"
  62                 "       subs    %w[rounds], %w[rounds], #3      ;"
  63                 "       aese    v0.16b, v1.16b                  ;"
  64                 "       aesmc   v0.16b, v0.16b                  ;"
  65                 "       ld1     {v3.2d}, [%[key]], #16          ;"
  66                 "       bpl     1b                              ;"
  67                 "       aese    v0.16b, v2.16b                  ;"
  68                 "       eor     v0.16b, v0.16b, v3.16b          ;"
  69                 "       st1     {v0.16b}, %[out]                ;"
  70
  71         :       [out]           "=Q"(*out),
  72                 [key]           "=r"(dummy0),
  73                 [rounds]        "=r"(dummy1)
  74         :       [in]            "Q"(*in),
  75                                 "1"(ctx->key_enc),
  76                                 "2"(num_rounds(ctx) - 2)
  77         :       "cc");
  78
  79         kernel_neon_end();
  80 }
  81
  82 static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
  83 {
  84         struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  85         struct aes_block *out = (struct aes_block *)dst;
  86         struct aes_block const *in = (struct aes_block *)src;
  87         void *dummy0;
  88         int dummy1;
  89
  90         kernel_neon_begin_partial(4);
  91
  92         __asm__("       ld1     {v0.16b}, %[in]                 ;"
  93                 "       ld1     {v1.2d}, [%[key]], #16          ;"
  94                 "       cmp     %w[rounds], #10                 ;"
  95                 "       bmi     0f                              ;"
  96                 "       bne     3f                              ;"
  97                 "       mov     v3.16b, v1.16b                  ;"
  98                 "       b       2f                              ;"
  99                 "0:     mov     v2.16b, v1.16b                  ;"
 100                 "       ld1     {v3.2d}, [%[key]], #16          ;"
 101                 "1:     aesd    v0.16b, v2.16b                  ;"
 102                 "       aesimc  v0.16b, v0.16b                  ;"
 103                 "2:     ld1     {v1.2d}, [%[key]], #16          ;"
 104                 "       aesd    v0.16b, v3.16b                  ;"
 105                 "       aesimc  v0.16b, v0.16b                  ;"
 106                 "3:     ld1     {v2.2d}, [%[key]], #16          ;"
 107                 "       subs    %w[rounds], %w[rounds], #3      ;"
 108                 "       aesd    v0.16b, v1.16b                  ;"
 109                 "       aesimc  v0.16b, v0.16b                  ;"
 110                 "       ld1     {v3.2d}, [%[key]], #16          ;"
 111                 "       bpl     1b                              ;"
 112                 "       aesd    v0.16b, v2.16b                  ;"
 113                 "       eor     v0.16b, v0.16b, v3.16b          ;"
 114                 "       st1     {v0.16b}, %[out]                ;"
 115
 116         :       [out]           "=Q"(*out),
 117                 [key]           "=r"(dummy0),
 118                 [rounds]        "=r"(dummy1)
 119         :       [in]            "Q"(*in),
 120                                 "1"(ctx->key_dec),
 121                                 "2"(num_rounds(ctx) - 2)
 122         :       "cc");
 123
 124         kernel_neon_end();
 125 }
 126
 127 static struct crypto_alg aes_alg = {
 128         .cra_name               = "aes",
 129         .cra_driver_name        = "aes-ce",
 130         .cra_priority           = 300,
 131         .cra_flags              = CRYPTO_ALG_TYPE_CIPHER,
 132         .cra_blocksize          = AES_BLOCK_SIZE,
 133         .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 134         .cra_module             = THIS_MODULE,
 135         .cra_cipher = {
 136                 .cia_min_keysize        = AES_MIN_KEY_SIZE,
 137                 .cia_max_keysize        = AES_MAX_KEY_SIZE,
 138                 .cia_setkey             = crypto_aes_set_key,
 139                 .cia_encrypt            = aes_cipher_encrypt,
 140                 .cia_decrypt            = aes_cipher_decrypt
 141         }
 142 };
 143
 144 static int __init aes_mod_init(void)
 145 {
 146         return crypto_register_alg(&aes_alg);
 147 }
 148
 149 static void __exit aes_mod_exit(void)
 150 {
 151         crypto_unregister_alg(&aes_alg);
 152 }
 153
 154 module_cpu_feature_match(AES, aes_mod_init);
 155 module_exit(aes_mod_exit);