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crypto: s390 - add System z hardware support for XTS mode 

This patch adds System z hardware acceleration support for the AES XTS mode.
The hardware support is available beginning with System z196.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Gerald Schaefer 2011-04-26 16:12:42 +10:00 committed by Herbert Xu
parent 98971f8439
commit 99d9722215
3 changed files with 271 additions and 13 deletions
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233
arch/s390/crypto/aes_s390.c
View File

@ -45,6 +45,24 @@ struct s390_aes_ctx {
} fallback;
};
struct pcc_param {
u8 key[32];
u8 tweak[16];
u8 block[16];
u8 bit[16];
u8 xts[16];
};
struct s390_xts_ctx {
u8 key[32];
u8 xts_param[16];
struct pcc_param pcc;
long enc;
long dec;
int key_len;
struct crypto_blkcipher *fallback;
};
/*
* Check if the key_len is supported by the HW.
* Returns 0 if it is, a positive number if it is not and software fallback is
@ -504,8 +522,211 @@ static struct crypto_alg cbc_aes_alg = {
}
};
static int xts_fallback_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int len)
{
struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);
unsigned int ret;
xts_ctx->fallback->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
xts_ctx->fallback->base.crt_flags |= (tfm->crt_flags &
CRYPTO_TFM_REQ_MASK);
ret = crypto_blkcipher_setkey(xts_ctx->fallback, key, len);
if (ret) {
tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
tfm->crt_flags |= (xts_ctx->fallback->base.crt_flags &
CRYPTO_TFM_RES_MASK);
}
return ret;
}
static int xts_fallback_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(desc->tfm);
struct crypto_blkcipher *tfm;
unsigned int ret;
tfm = desc->tfm;
desc->tfm = xts_ctx->fallback;
ret = crypto_blkcipher_decrypt_iv(desc, dst, src, nbytes);
desc->tfm = tfm;
return ret;
}
static int xts_fallback_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(desc->tfm);
struct crypto_blkcipher *tfm;
unsigned int ret;
tfm = desc->tfm;
desc->tfm = xts_ctx->fallback;
ret = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
desc->tfm = tfm;
return ret;
}
static int xts_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
switch (key_len) {
case 32:
xts_ctx->enc = KM_XTS_128_ENCRYPT;
xts_ctx->dec = KM_XTS_128_DECRYPT;
memcpy(xts_ctx->key + 16, in_key, 16);
memcpy(xts_ctx->pcc.key + 16, in_key + 16, 16);
break;
case 48:
xts_ctx->enc = 0;
xts_ctx->dec = 0;
xts_fallback_setkey(tfm, in_key, key_len);
break;
case 64:
xts_ctx->enc = KM_XTS_256_ENCRYPT;
xts_ctx->dec = KM_XTS_256_DECRYPT;
memcpy(xts_ctx->key, in_key, 32);
memcpy(xts_ctx->pcc.key, in_key + 32, 32);
break;
default:
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
xts_ctx->key_len = key_len;
return 0;
}
static int xts_aes_crypt(struct blkcipher_desc *desc, long func,
struct s390_xts_ctx *xts_ctx,
struct blkcipher_walk *walk)
{
unsigned int offset = (xts_ctx->key_len >> 1) & 0x10;
int ret = blkcipher_walk_virt(desc, walk);
unsigned int nbytes = walk->nbytes;
unsigned int n;
u8 *in, *out;
void *param;
if (!nbytes)
goto out;
memset(xts_ctx->pcc.block, 0, sizeof(xts_ctx->pcc.block));
memset(xts_ctx->pcc.bit, 0, sizeof(xts_ctx->pcc.bit));
memset(xts_ctx->pcc.xts, 0, sizeof(xts_ctx->pcc.xts));
memcpy(xts_ctx->pcc.tweak, walk->iv, sizeof(xts_ctx->pcc.tweak));
param = xts_ctx->pcc.key + offset;
ret = crypt_s390_pcc(func, param);
BUG_ON(ret < 0);
memcpy(xts_ctx->xts_param, xts_ctx->pcc.xts, 16);
param = xts_ctx->key + offset;
do {
/* only use complete blocks */
n = nbytes & ~(AES_BLOCK_SIZE - 1);
out = walk->dst.virt.addr;
in = walk->src.virt.addr;
ret = crypt_s390_km(func, param, out, in, n);
BUG_ON(ret < 0 || ret != n);
nbytes &= AES_BLOCK_SIZE - 1;
ret = blkcipher_walk_done(desc, walk, nbytes);
} while ((nbytes = walk->nbytes));
out:
return ret;
}
static int xts_aes_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
if (unlikely(xts_ctx->key_len == 48))
return xts_fallback_encrypt(desc, dst, src, nbytes);
blkcipher_walk_init(&walk, dst, src, nbytes);
return xts_aes_crypt(desc, xts_ctx->enc, xts_ctx, &walk);
}
static int xts_aes_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
if (unlikely(xts_ctx->key_len == 48))
return xts_fallback_decrypt(desc, dst, src, nbytes);
blkcipher_walk_init(&walk, dst, src, nbytes);
return xts_aes_crypt(desc, xts_ctx->dec, xts_ctx, &walk);
}
static int xts_fallback_init(struct crypto_tfm *tfm)
{
const char *name = tfm->__crt_alg->cra_name;
struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);
xts_ctx->fallback = crypto_alloc_blkcipher(name, 0,
CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(xts_ctx->fallback)) {
pr_err("Allocating XTS fallback algorithm %s failed\n",
name);
return PTR_ERR(xts_ctx->fallback);
}
return 0;
}
static void xts_fallback_exit(struct crypto_tfm *tfm)
{
struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);
crypto_free_blkcipher(xts_ctx->fallback);
xts_ctx->fallback = NULL;
}
static struct crypto_alg xts_aes_alg = {
.cra_name = "xts(aes)",
.cra_driver_name = "xts-aes-s390",
.cra_priority = CRYPT_S390_COMPOSITE_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER |
CRYPTO_ALG_NEED_FALLBACK,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct s390_xts_ctx),
.cra_type = &crypto_blkcipher_type,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(xts_aes_alg.cra_list),
.cra_init = xts_fallback_init,
.cra_exit = xts_fallback_exit,
.cra_u = {
.blkcipher = {
.min_keysize = 2 * AES_MIN_KEY_SIZE,
.max_keysize = 2 * AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = xts_aes_set_key,
.encrypt = xts_aes_encrypt,
.decrypt = xts_aes_decrypt,
}
}
};
static int __init aes_s390_init(void)
{
unsigned long long facility_bits[2];
int ret;
if (crypt_s390_func_available(KM_AES_128_ENCRYPT, CRYPT_S390_MSA))
@ -535,9 +756,20 @@ static int __init aes_s390_init(void)
if (ret)
goto cbc_aes_err;
if (crypt_s390_func_available(KM_XTS_128_ENCRYPT,
CRYPT_S390_MSA | CRYPT_S390_MSA4) &&
crypt_s390_func_available(KM_XTS_256_ENCRYPT,
CRYPT_S390_MSA | CRYPT_S390_MSA4)) {
ret = crypto_register_alg(&xts_aes_alg);
if (ret)
goto xts_aes_err;
}
out:
return ret;
xts_aes_err:
crypto_unregister_alg(&cbc_aes_alg);
cbc_aes_err:
crypto_unregister_alg(&ecb_aes_alg);
ecb_aes_err:
@ -548,6 +780,7 @@ aes_err:
static void __exit aes_s390_fini(void)
{
crypto_unregister_alg(&xts_aes_alg);
crypto_unregister_alg(&cbc_aes_alg);
crypto_unregister_alg(&ecb_aes_alg);
crypto_unregister_alg(&aes_alg);

31
arch/s390/crypto/crypt_s390.h
View File

@ -55,6 +55,10 @@ enum crypt_s390_km_func {
KM_AES_192_DECRYPT = CRYPT_S390_KM | 0x13 | 0x80,
KM_AES_256_ENCRYPT = CRYPT_S390_KM | 0x14,
KM_AES_256_DECRYPT = CRYPT_S390_KM | 0x14 | 0x80,
KM_XTS_128_ENCRYPT = CRYPT_S390_KM | 0x32,
KM_XTS_128_DECRYPT = CRYPT_S390_KM | 0x32 | 0x80,
KM_XTS_256_ENCRYPT = CRYPT_S390_KM | 0x34,
KM_XTS_256_DECRYPT = CRYPT_S390_KM | 0x34 | 0x80,
};
/*
@ -334,4 +338,31 @@ static inline int crypt_s390_func_available(int func,
return (status[func >> 3] & (0x80 >> (func & 7))) != 0;
}
/**
* crypt_s390_pcc:
* @func: the function code passed to KM; see crypt_s390_km_func
* @param: address of parameter block; see POP for details on each func
*
* Executes the PCC (PERFORM CRYPTOGRAPHIC COMPUTATION) operation of the CPU.
*
* Returns -1 for failure, 0 for success.
*/
static inline int crypt_s390_pcc(long func, void *param)
{
register long __func asm("0") = func & 0x7f; /* encrypt or decrypt */
register void *__param asm("1") = param;
int ret = -1;
asm volatile(
"0: .insn rre,0xb92c0000,0,0 \n" /* PCC opcode */
"1: brc 1,0b \n" /* handle partial completion */
" la %0,0\n"
"2:\n"
EX_TABLE(0b,2b) EX_TABLE(1b,2b)
: "+d" (ret)
: "d" (__func), "a" (__param) : "cc", "memory");
return ret;
}
#endif /* _CRYPTO_ARCH_S390_CRYPT_S390_H */

20
drivers/crypto/Kconfig
View File

@ -131,20 +131,14 @@ config CRYPTO_AES_S390
select CRYPTO_BLKCIPHER
help
This is the s390 hardware accelerated implementation of the
AES cipher algorithms (FIPS-197). AES uses the Rijndael
algorithm.
AES cipher algorithms (FIPS-197).
Rijndael appears to be consistently a very good performer in
both hardware and software across a wide range of computing
environments regardless of its use in feedback or non-feedback
modes. Its key setup time is excellent, and its key agility is
good. Rijndael's very low memory requirements make it very well
suited for restricted-space environments, in which it also
demonstrates excellent performance. Rijndael's operations are
among the easiest to defend against power and timing attacks.
On s390 the System z9-109 currently only supports the key size
of 128 bit.
As of z9 the ECB and CBC modes are hardware accelerated
for 128 bit keys.
As of z10 the ECB and CBC modes are hardware accelerated
for all AES key sizes.
As of z196 the XTS mode is hardware accelerated for 256 and
512 bit keys.
config S390_PRNG
tristate "Pseudo random number generator device driver"