Commit 12ac3efe authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon

arm64/crypto: use crypto instructions to generate AES key schedule

This patch implements the AES key schedule generation using ARMv8
Crypto Instructions. It replaces the table based C implementation
in aes_generic.ko, which means we can drop the dependency on that
module.
Tested-by: default avatarSteve Capper <steve.capper@linaro.org>
Acked-by: default avatarSteve Capper <steve.capper@linaro.org>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 286fb1cc
......@@ -27,20 +27,19 @@ config CRYPTO_AES_ARM64_CE
tristate "AES core cipher using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_ALGAPI
select CRYPTO_AES
config CRYPTO_AES_ARM64_CE_CCM
tristate "AES in CCM mode using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_ALGAPI
select CRYPTO_AES
select CRYPTO_AES_ARM64_CE
select CRYPTO_AEAD
config CRYPTO_AES_ARM64_CE_BLK
tristate "AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_BLKCIPHER
select CRYPTO_AES
select CRYPTO_AES_ARM64_CE
select CRYPTO_ABLK_HELPER
config CRYPTO_AES_ARM64_NEON_BLK
......
......@@ -16,6 +16,8 @@
#include <linux/crypto.h>
#include <linux/module.h>
#include "aes-ce-setkey.h"
static int num_rounds(struct crypto_aes_ctx *ctx)
{
/*
......@@ -48,7 +50,7 @@ static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key,
struct crypto_aes_ctx *ctx = crypto_aead_ctx(tfm);
int ret;
ret = crypto_aes_expand_key(ctx, in_key, key_len);
ret = ce_aes_expandkey(ctx, in_key, key_len);
if (!ret)
return 0;
......
......@@ -14,6 +14,8 @@
#include <linux/crypto.h>
#include <linux/module.h>
#include "aes-ce-setkey.h"
MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
......@@ -124,6 +126,114 @@ static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
kernel_neon_end();
}
/*
* aes_sub() - use the aese instruction to perform the AES sbox substitution
* on each byte in 'input'
*/
static u32 aes_sub(u32 input)
{
u32 ret;
__asm__("dup v1.4s, %w[in] ;"
"movi v0.16b, #0 ;"
"aese v0.16b, v1.16b ;"
"umov %w[out], v0.4s[0] ;"
: [out] "=r"(ret)
: [in] "r"(input)
: "v0","v1");
return ret;
}
int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
unsigned int key_len)
{
/*
* The AES key schedule round constants
*/
static u8 const rcon[] = {
0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
};
u32 kwords = key_len / sizeof(u32);
struct aes_block *key_enc, *key_dec;
int i, j;
if (key_len != AES_KEYSIZE_128 &&
key_len != AES_KEYSIZE_192 &&
key_len != AES_KEYSIZE_256)
return -EINVAL;
memcpy(ctx->key_enc, in_key, key_len);
ctx->key_length = key_len;
kernel_neon_begin_partial(2);
for (i = 0; i < sizeof(rcon); i++) {
u32 *rki = ctx->key_enc + (i * kwords);
u32 *rko = rki + kwords;
rko[0] = ror32(aes_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0];
rko[1] = rko[0] ^ rki[1];
rko[2] = rko[1] ^ rki[2];
rko[3] = rko[2] ^ rki[3];
if (key_len == AES_KEYSIZE_192) {
if (i >= 7)
break;
rko[4] = rko[3] ^ rki[4];
rko[5] = rko[4] ^ rki[5];
} else if (key_len == AES_KEYSIZE_256) {
if (i >= 6)
break;
rko[4] = aes_sub(rko[3]) ^ rki[4];
rko[5] = rko[4] ^ rki[5];
rko[6] = rko[5] ^ rki[6];
rko[7] = rko[6] ^ rki[7];
}
}
/*
* Generate the decryption keys for the Equivalent Inverse Cipher.
* This involves reversing the order of the round keys, and applying
* the Inverse Mix Columns transformation on all but the first and
* the last one.
*/
key_enc = (struct aes_block *)ctx->key_enc;
key_dec = (struct aes_block *)ctx->key_dec;
j = num_rounds(ctx);
key_dec[0] = key_enc[j];
for (i = 1, j--; j > 0; i++, j--)
__asm__("ld1 {v0.16b}, %[in] ;"
"aesimc v1.16b, v0.16b ;"
"st1 {v1.16b}, %[out] ;"
: [out] "=Q"(key_dec[i])
: [in] "Q"(key_enc[j])
: "v0","v1");
key_dec[i] = key_enc[0];
kernel_neon_end();
return 0;
}
EXPORT_SYMBOL(ce_aes_expandkey);
int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
int ret;
ret = ce_aes_expandkey(ctx, in_key, key_len);
if (!ret)
return 0;
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
EXPORT_SYMBOL(ce_aes_setkey);
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-ce",
......@@ -135,7 +245,7 @@ static struct crypto_alg aes_alg = {
.cra_cipher = {
.cia_min_keysize = AES_MIN_KEY_SIZE,
.cia_max_keysize = AES_MAX_KEY_SIZE,
.cia_setkey = crypto_aes_set_key,
.cia_setkey = ce_aes_setkey,
.cia_encrypt = aes_cipher_encrypt,
.cia_decrypt = aes_cipher_decrypt
}
......
int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len);
int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
unsigned int key_len);
......@@ -16,9 +16,13 @@
#include <linux/module.h>
#include <linux/cpufeature.h>
#include "aes-ce-setkey.h"
#ifdef USE_V8_CRYPTO_EXTENSIONS
#define MODE "ce"
#define PRIO 300
#define aes_setkey ce_aes_setkey
#define aes_expandkey ce_aes_expandkey
#define aes_ecb_encrypt ce_aes_ecb_encrypt
#define aes_ecb_decrypt ce_aes_ecb_decrypt
#define aes_cbc_encrypt ce_aes_cbc_encrypt
......@@ -30,6 +34,8 @@ MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
#else
#define MODE "neon"
#define PRIO 200
#define aes_setkey crypto_aes_set_key
#define aes_expandkey crypto_aes_expand_key
#define aes_ecb_encrypt neon_aes_ecb_encrypt
#define aes_ecb_decrypt neon_aes_ecb_decrypt
#define aes_cbc_encrypt neon_aes_cbc_encrypt
......@@ -79,10 +85,10 @@ static int xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
struct crypto_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int ret;
ret = crypto_aes_expand_key(&ctx->key1, in_key, key_len / 2);
ret = aes_expandkey(&ctx->key1, in_key, key_len / 2);
if (!ret)
ret = crypto_aes_expand_key(&ctx->key2, &in_key[key_len / 2],
key_len / 2);
ret = aes_expandkey(&ctx->key2, &in_key[key_len / 2],
key_len / 2);
if (!ret)
return 0;
......@@ -288,7 +294,7 @@ static struct crypto_alg aes_algs[] = { {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = crypto_aes_set_key,
.setkey = aes_setkey,
.encrypt = ecb_encrypt,
.decrypt = ecb_decrypt,
},
......@@ -306,7 +312,7 @@ static struct crypto_alg aes_algs[] = { {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = crypto_aes_set_key,
.setkey = aes_setkey,
.encrypt = cbc_encrypt,
.decrypt = cbc_decrypt,
},
......@@ -324,7 +330,7 @@ static struct crypto_alg aes_algs[] = { {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = crypto_aes_set_key,
.setkey = aes_setkey,
.encrypt = ctr_encrypt,
.decrypt = ctr_encrypt,
},
......
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