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/* crc-armv8-ce.c - ARMv8-CE PMULL accelerated CRC implementation
* Copyright (C) 2019 Jussi Kivilinna <jussi.kivilinna@iki.fi>
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "g10lib.h"
#include "bithelp.h"
#include "bufhelp.h"
#if defined(ENABLE_ARM_CRYPTO_SUPPORT) && defined(__AARCH64EL__) && \
defined(HAVE_COMPATIBLE_GCC_AARCH64_PLATFORM_AS) && \
defined(HAVE_GCC_INLINE_ASM_AARCH64_CRYPTO)
#define ALIGNED_16 __attribute__ ((aligned (16)))
struct u16_unaligned_s
{
u16 a;
} __attribute__((packed, aligned (1), may_alias));
struct u32_unaligned_s
{
u32 a;
} __attribute__((packed, aligned (1), may_alias));
/* Constants structure for generic reflected/non-reflected CRC32 PMULL
* functions. */
struct crc32_consts_s
{
/* k: { x^(32*17), x^(32*15), x^(32*5), x^(32*3), x^(32*2), 0 } mod P(x) */
u64 k[6];
/* my_p: { floor(x^64 / P(x)), P(x) } */
u64 my_p[2];
};
/* PMULL constants for CRC32 and CRC32RFC1510. */
static const struct crc32_consts_s crc32_consts ALIGNED_16 =
{
{ /* k[6] = reverse_33bits( x^(32*y) mod P(x) ) */
U64_C(0x154442bd4), U64_C(0x1c6e41596), /* y = { 17, 15 } */
U64_C(0x1751997d0), U64_C(0x0ccaa009e), /* y = { 5, 3 } */
U64_C(0x163cd6124), 0 /* y = 2 */
},
{ /* my_p[2] = reverse_33bits ( { floor(x^64 / P(x)), P(x) } ) */
U64_C(0x1f7011641), U64_C(0x1db710641)
}
};
/* PMULL constants for CRC24RFC2440 (polynomial multiplied with x⁸). */
static const struct crc32_consts_s crc24rfc2440_consts ALIGNED_16 =
{
{ /* k[6] = x^(32*y) mod P(x) << 32*/
U64_C(0x08289a00) << 32, U64_C(0x74b44a00) << 32, /* y = { 17, 15 } */
U64_C(0xc4b14d00) << 32, U64_C(0xfd7e0c00) << 32, /* y = { 5, 3 } */
U64_C(0xd9fe8c00) << 32, 0 /* y = 2 */
},
{ /* my_p[2] = { floor(x^64 / P(x)), P(x) } */
U64_C(0x1f845fe24), U64_C(0x1864cfb00)
}
};
u32 _gcry_crc32r_armv8_ce_reduction_4 (u32 data, u32 crc,
const struct crc32_consts_s *consts);
void _gcry_crc32r_armv8_ce_bulk (u32 *pcrc, const byte *inbuf, size_t inlen,
const struct crc32_consts_s *consts);
u32 _gcry_crc32_armv8_ce_reduction_4 (u32 data, u32 crc,
const struct crc32_consts_s *consts);
void _gcry_crc32_armv8_ce_bulk (u32 *pcrc, const byte *inbuf, size_t inlen,
const struct crc32_consts_s *consts);
static inline void
crc32r_less_than_16 (u32 *pcrc, const byte *inbuf, size_t inlen,
const struct crc32_consts_s *consts)
{
u32 crc = *pcrc;
u32 data;
while (inlen >= 4)
{
data = ((const struct u32_unaligned_s *)inbuf)->a;
data ^= crc;
inlen -= 4;
inbuf += 4;
crc = _gcry_crc32r_armv8_ce_reduction_4 (data, 0, consts);
}
switch (inlen)
{
case 0:
break;
case 1:
data = inbuf[0];
data ^= crc;
data <<= 24;
crc >>= 8;
crc = _gcry_crc32r_armv8_ce_reduction_4 (data, crc, consts);
break;
case 2:
data = ((const struct u16_unaligned_s *)inbuf)->a;
data ^= crc;
data <<= 16;
crc >>= 16;
crc = _gcry_crc32r_armv8_ce_reduction_4 (data, crc, consts);
break;
case 3:
data = ((const struct u16_unaligned_s *)inbuf)->a;
data |= inbuf[2] << 16;
data ^= crc;
data <<= 8;
crc >>= 24;
crc = _gcry_crc32r_armv8_ce_reduction_4 (data, crc, consts);
break;
}
*pcrc = crc;
}
static inline void
crc32_less_than_16 (u32 *pcrc, const byte *inbuf, size_t inlen,
const struct crc32_consts_s *consts)
{
u32 crc = *pcrc;
u32 data;
while (inlen >= 4)
{
data = ((const struct u32_unaligned_s *)inbuf)->a;
data ^= crc;
data = _gcry_bswap32(data);
inlen -= 4;
inbuf += 4;
crc = _gcry_crc32_armv8_ce_reduction_4 (data, 0, consts);
}
switch (inlen)
{
case 0:
break;
case 1:
data = inbuf[0];
data ^= crc;
data = data & 0xffU;
crc = _gcry_bswap32(crc >> 8);
crc = _gcry_crc32_armv8_ce_reduction_4 (data, crc, consts);
break;
case 2:
data = ((const struct u16_unaligned_s *)inbuf)->a;
data ^= crc;
data = _gcry_bswap32(data << 16);
crc = _gcry_bswap32(crc >> 16);
crc = _gcry_crc32_armv8_ce_reduction_4 (data, crc, consts);
break;
case 3:
data = ((const struct u16_unaligned_s *)inbuf)->a;
data |= inbuf[2] << 16;
data ^= crc;
data = _gcry_bswap32(data << 8);
crc = crc & 0xff000000U;
crc = _gcry_crc32_armv8_ce_reduction_4 (data, crc, consts);
break;
}
*pcrc = crc;
}
void
_gcry_crc32_armv8_ce_pmull (u32 *pcrc, const byte *inbuf, size_t inlen)
{
const struct crc32_consts_s *consts = &crc32_consts;
if (!inlen)
return;
if (inlen >= 16)
_gcry_crc32r_armv8_ce_bulk (pcrc, inbuf, inlen, consts);
else
crc32r_less_than_16 (pcrc, inbuf, inlen, consts);
}
void
_gcry_crc24rfc2440_armv8_ce_pmull (u32 *pcrc, const byte *inbuf, size_t inlen)
{
const struct crc32_consts_s *consts = &crc24rfc2440_consts;
if (!inlen)
return;
/* Note: *pcrc in input endian. */
if (inlen >= 16)
_gcry_crc32_armv8_ce_bulk (pcrc, inbuf, inlen, consts);
else
crc32_less_than_16 (pcrc, inbuf, inlen, consts);
}
#endif