mbedtls/library/armv8ce_aes.c
Markku-Juhani O. Saarinen dfb6015ca7 Implements AES and GCM with ARMv8 Crypto Extensions
A compact patch that provides AES and GCM implementations that utilize the
ARMv8 Crypto Extensions. The config flag is MBEDTLS_ARMV8CE_AES_C, which
is disabled by default as we don't do runtime checking for the feature.
The new implementation lives in armv8ce_aes.c.

Provides similar functionality to https://github.com/ARMmbed/mbedtls/pull/432
Thanks to Barry O'Rourke and others for that contribtion.

Tested on a Cortex A53 device and QEMU. On a midrange phone the real AES-GCM
throughput increases about 4x, while raw AES speed is up to 10x faster.

When cross-compiling, you want to set something like:

  export CC='aarch64-linux-gnu-gcc'
  export CFLAGS='-Ofast -march=armv8-a+crypto'
  scripts/config.pl set MBEDTLS_ARMV8CE_AES_C

QEMU seems to also need

  export LDFLAGS='-static'

Then run normal make or cmake etc.
2020-09-07 12:02:41 +01:00

144 lines
4.5 KiB
C

/*
* ARMv8 Cryptography Extensions -- Optimized code for AES and GCM
*
* Copyright (C) 2006-2017, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_ARMV8CE_AES_C)
#include <arm_neon.h>
#include "mbedtls/armv8ce_aes.h"
#ifndef asm
#define asm __asm
#endif
/*
* [ARMv8 Crypto Extensions] AES-ECB block en(de)cryption
*/
#if defined(MBEDTLS_AES_C)
int mbedtls_armv8ce_aes_crypt_ecb( mbedtls_aes_context *ctx,
int mode,
const unsigned char input[16],
unsigned char output[16] )
{
unsigned int i;
const uint8_t *rk;
uint8x16_t x, k;
x = vld1q_u8( input ); // input block
rk = (const uint8_t *) ctx->rk; // round keys
if( mode == MBEDTLS_AES_ENCRYPT )
{
for( i = ctx->nr - 1; i ; i-- ) // encryption loop
{
k = vld1q_u8( rk );
rk += 16;
x = vaeseq_u8( x, k );
x = vaesmcq_u8( x );
}
k = vld1q_u8( rk );
rk += 16;
x = vaeseq_u8( x, k );
}
else
{
for( i = ctx->nr - 1; i ; i-- ) // decryption loop
{
k = vld1q_u8( rk );
rk += 16;
x = vaesdq_u8( x, k );
x = vaesimcq_u8( x );
}
k = vld1q_u8( rk );
rk += 16;
x = vaesdq_u8( x, k );
}
k = vld1q_u8( rk ); // final key just XORed
x = veorq_u8( x, k );
vst1q_u8( output, x ); // write out
return ( 0 );
}
#endif /* MBEDTLS_AES_C */
/*
* [ARMv8 Crypto Extensions] Multiply in GF(2^128) for GCM
*/
#if defined(MBEDTLS_GCM_C)
void mbedtls_armv8ce_gcm_mult( unsigned char c[16],
const unsigned char a[16],
const unsigned char b[16] )
{
// GCM's GF(2^128) polynomial basis is x^128 + x^7 + x^2 + x + 1
const uint64x2_t base = { 0, 0x86 }; // note missing LS bit
register uint8x16_t vc asm( "v0" ); // named registers
register uint8x16_t va asm( "v1" ); // (to avoid conflict)
register uint8x16_t vb asm( "v2" );
register uint64x2_t vp asm( "v3" );
va = vld1q_u8( a ); // load inputs
vb = vld1q_u8( b );
vp = base;
asm (
"rbit %1.16b, %1.16b \n\t" // reverse bit order
"rbit %2.16b, %2.16b \n\t"
"pmull2 %0.1q, %1.2d, %2.2d \n\t" // v0 = a.hi * b.hi
"pmull2 v4.1q, %0.2d, %3.2d \n\t" // mul v0 by x^64, reduce
"ext %0.16b, %0.16b, %0.16b, #8 \n\t"
"eor %0.16b, %0.16b, v4.16b \n\t"
"ext v5.16b, %2.16b, %2.16b, #8 \n\t" // (swap hi and lo in b)
"pmull v4.1q, %1.1d, v5.1d \n\t" // v0 ^= a.lo * b.hi
"eor %0.16b, %0.16b, v4.16b \n\t"
"pmull2 v4.1q, %1.2d, v5.2d \n\t" // v0 ^= a.hi * b.lo
"eor %0.16b, %0.16b, v4.16b \n\t"
"pmull2 v4.1q, %0.2d, %3.2d \n\t" // mul v0 by x^64, reduce
"ext %0.16b, %0.16b, %0.16b, #8 \n\t"
"eor %0.16b, %0.16b, v4.16b \n\t"
"pmull v4.1q, %1.1d, %2.1d \n\t" // v0 ^= a.lo * b.lo
"eor %0.16b, %0.16b, v4.16b \n\t"
"rbit %0.16b, %0.16b \n\t" // reverse bits for output
: "=w" (vc) // q0: output
: "w" (va), "w" (vb), "w" (vp) // q1, q2: input
: "v4", "v5" // q4, q5: clobbered
);
vst1q_u8( c, vc ); // write out
}
#endif /* MBEDTLS_GCM_C */
#endif /* MBEDTLS_ARMV8CE_AES_C */