arch/arm64/crypto/aes-ctr-fallback.h

   1 /*
   2  * Fallback for sync aes(ctr) in contexts where kernel mode NEON
   3  * is not allowed
   4  *
   5  * Copyright (C) 2017 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
  12 #include <crypto/aes.h>
  13 #include <crypto/internal/skcipher.h>
  14
  15 asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
  16
  17 static inline int aes_ctr_encrypt_fallback(struct crypto_aes_ctx *ctx,
  18                                            struct skcipher_request *req)
  19 {
  20         struct skcipher_walk walk;
  21         u8 buf[AES_BLOCK_SIZE];
  22         int err;
  23
  24         err = skcipher_walk_virt(&walk, req, true);
  25
  26         while (walk.nbytes > 0) {
  27                 u8 *dst = walk.dst.virt.addr;
  28                 u8 *src = walk.src.virt.addr;
  29                 int nbytes = walk.nbytes;
  30                 int tail = 0;
  31
  32                 if (nbytes < walk.total) {
  33                         nbytes = round_down(nbytes, AES_BLOCK_SIZE);
  34                         tail = walk.nbytes % AES_BLOCK_SIZE;
  35                 }
  36
  37                 do {
  38                         int bsize = min(nbytes, AES_BLOCK_SIZE);
  39
  40                         __aes_arm64_encrypt(ctx->key_enc, buf, walk.iv,
  41                                             6 + ctx->key_length / 4);
  42                         crypto_xor_cpy(dst, src, buf, bsize);
  43                         crypto_inc(walk.iv, AES_BLOCK_SIZE);
  44
  45                         dst += AES_BLOCK_SIZE;
  46                         src += AES_BLOCK_SIZE;
  47                         nbytes -= AES_BLOCK_SIZE;
  48                 } while (nbytes > 0);
  49
  50                 err = skcipher_walk_done(&walk, tail);
  51         }
  52         return err;
  53 }