LXR linux/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
  12asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
  13
  14static 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}
  51