sysdeps/aarch64/chacha20_arch.h

   1 /* Chacha20 implementation, used on arc4random.
   2    Copyright (C) 2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <ldsodefs.h>
  20 #include <stdbool.h>
  21
  22 unsigned int __chacha20_neon_blocks4 (uint32_t *state, uint8_t *dst,
  23                                       const uint8_t *src, size_t nblks)
  24      attribute_hidden;
  25
  26 static void
  27 chacha20_crypt (uint32_t *state, uint8_t *dst, const uint8_t *src,
  28                 size_t bytes)
  29 {
  30   _Static_assert (CHACHA20_BUFSIZE % 4 == 0,
  31                   "CHACHA20_BUFSIZE not multiple of 4");
  32   _Static_assert (CHACHA20_BUFSIZE > CHACHA20_BLOCK_SIZE * 4,
  33                   "CHACHA20_BUFSIZE <= CHACHA20_BLOCK_SIZE * 4");
  34 #ifdef __AARCH64EL__
  35   __chacha20_neon_blocks4 (state, dst, src,
  36                            CHACHA20_BUFSIZE / CHACHA20_BLOCK_SIZE);
  37 #else
  38   chacha20_crypt_generic (state, dst, src, bytes);
  39 #endif
  40 }