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

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Fallback for sync aes(ctr) in contexts where kernel mode NEON
   4  * is not allowed
   5  *
   6  * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
   7  */
   8
   9 #include <crypto/aes.h>
  10 #include <crypto/internal/skcipher.h>
  11
  12 asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
  13
  14 static inline int aes_ctr_encrypt_fallback(struct crypto_aes_ctx *ctx,
  15                                            struct skcipher_request *req)
  16 {
  17         struct skcipher_walk walk;
  18         u8 buf[AES_BLOCK_SIZE];
  19         int err;
  20
  21         err = skcipher_walk_virt(&walk, req, true);
  22
  23         while (walk.nbytes > 0) {
  24                 u8 *dst = walk.dst.virt.addr;
  25                 u8 *src = walk.src.virt.addr;
  26                 int nbytes = walk.nbytes;
  27                 int tail = 0;
  28
  29                 if (nbytes < walk.total) {
  30                         nbytes = round_down(nbytes, AES_BLOCK_SIZE);
  31                         tail = walk.nbytes % AES_BLOCK_SIZE;
  32                 }
  33
  34                 do {
  35                         int bsize = min(nbytes, AES_BLOCK_SIZE);
  36
  37                         __aes_arm64_encrypt(ctx->key_enc, buf, walk.iv,
  38                                             6 + ctx->key_length / 4);
  39                         crypto_xor_cpy(dst, src, buf, bsize);
  40                         crypto_inc(walk.iv, AES_BLOCK_SIZE);
  41
  42                         dst += AES_BLOCK_SIZE;
  43                         src += AES_BLOCK_SIZE;
  44                         nbytes -= AES_BLOCK_SIZE;
  45                 } while (nbytes > 0);
  46
  47                 err = skcipher_walk_done(&walk, tail);
  48         }
  49         return err;
  50 }