linux/arch/arm64/crypto/aes-cipher-glue.c
Ard Biesheuvel bed593c0e8 crypto: arm64/aes - add scalar implementation
This adds a scalar implementation of AES, based on the precomputed tables
that are exposed by the generic AES code. Since rotates are cheap on arm64,
this implementation only uses the 4 core tables (of 1 KB each), and avoids
the prerotated ones, reducing the D-cache footprint by 75%.

On Cortex-A57, this code manages 13.0 cycles per byte, which is ~34% faster
than the generic C code. (Note that this is still >13x slower than the code
that uses the optional ARMv8 Crypto Extensions, which manages <1 cycles per
byte.)

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-01-13 00:26:49 +08:00

70 lines
1.9 KiB
C

/*
* Scalar AES core transform
*
* Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <crypto/aes.h>
#include <linux/crypto.h>
#include <linux/module.h>
asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
EXPORT_SYMBOL(__aes_arm64_encrypt);
asmlinkage void __aes_arm64_decrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
EXPORT_SYMBOL(__aes_arm64_decrypt);
static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
int rounds = 6 + ctx->key_length / 4;
__aes_arm64_encrypt(ctx->key_enc, out, in, rounds);
}
static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
int rounds = 6 + ctx->key_length / 4;
__aes_arm64_decrypt(ctx->key_dec, out, in, rounds);
}
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-arm64",
.cra_priority = 200,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct crypto_aes_ctx),
.cra_module = THIS_MODULE,
.cra_cipher.cia_min_keysize = AES_MIN_KEY_SIZE,
.cra_cipher.cia_max_keysize = AES_MAX_KEY_SIZE,
.cra_cipher.cia_setkey = crypto_aes_set_key,
.cra_cipher.cia_encrypt = aes_encrypt,
.cra_cipher.cia_decrypt = aes_decrypt
};
static int __init aes_init(void)
{
return crypto_register_alg(&aes_alg);
}
static void __exit aes_fini(void)
{
crypto_unregister_alg(&aes_alg);
}
module_init(aes_init);
module_exit(aes_fini);
MODULE_DESCRIPTION("Scalar AES cipher for arm64");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("aes");