linux/arch/s390/crypto/ghash_s390.c
Martin Schwidefsky 69c0e360f9 s390/crypto: cpacf function detection
The CPACF code makes some assumptions about the availablity of hardware
support. E.g. if the machine supports KM(AES-256) without chaining it is
assumed that KMC(AES-256) with chaining is available as well. For the
existing CPUs this is true but the architecturally correct way is to
check each CPACF functions on its own. This is what the query function
of each instructions is all about.

Reviewed-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-08-29 11:05:09 +02:00

157 lines
3.2 KiB
C

/*
* Cryptographic API.
*
* s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
*
* Copyright IBM Corp. 2011
* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
*/
#include <crypto/internal/hash.h>
#include <linux/module.h>
#include <linux/cpufeature.h>
#include <asm/cpacf.h>
#define GHASH_BLOCK_SIZE 16
#define GHASH_DIGEST_SIZE 16
struct ghash_ctx {
u8 key[GHASH_BLOCK_SIZE];
};
struct ghash_desc_ctx {
u8 icv[GHASH_BLOCK_SIZE];
u8 key[GHASH_BLOCK_SIZE];
u8 buffer[GHASH_BLOCK_SIZE];
u32 bytes;
};
static int ghash_init(struct shash_desc *desc)
{
struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
memset(dctx, 0, sizeof(*dctx));
memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
return 0;
}
static int ghash_setkey(struct crypto_shash *tfm,
const u8 *key, unsigned int keylen)
{
struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
if (keylen != GHASH_BLOCK_SIZE) {
crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
return -EINVAL;
}
memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
return 0;
}
static int ghash_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
unsigned int n;
u8 *buf = dctx->buffer;
if (dctx->bytes) {
u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
n = min(srclen, dctx->bytes);
dctx->bytes -= n;
srclen -= n;
memcpy(pos, src, n);
src += n;
if (!dctx->bytes) {
cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
GHASH_BLOCK_SIZE);
}
}
n = srclen & ~(GHASH_BLOCK_SIZE - 1);
if (n) {
cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
src += n;
srclen -= n;
}
if (srclen) {
dctx->bytes = GHASH_BLOCK_SIZE - srclen;
memcpy(buf, src, srclen);
}
return 0;
}
static int ghash_flush(struct ghash_desc_ctx *dctx)
{
u8 *buf = dctx->buffer;
if (dctx->bytes) {
u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
memset(pos, 0, dctx->bytes);
cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
dctx->bytes = 0;
}
return 0;
}
static int ghash_final(struct shash_desc *desc, u8 *dst)
{
struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
int ret;
ret = ghash_flush(dctx);
if (!ret)
memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
return ret;
}
static struct shash_alg ghash_alg = {
.digestsize = GHASH_DIGEST_SIZE,
.init = ghash_init,
.update = ghash_update,
.final = ghash_final,
.setkey = ghash_setkey,
.descsize = sizeof(struct ghash_desc_ctx),
.base = {
.cra_name = "ghash",
.cra_driver_name = "ghash-s390",
.cra_priority = 300,
.cra_flags = CRYPTO_ALG_TYPE_SHASH,
.cra_blocksize = GHASH_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct ghash_ctx),
.cra_module = THIS_MODULE,
},
};
static int __init ghash_mod_init(void)
{
if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
return -EOPNOTSUPP;
return crypto_register_shash(&ghash_alg);
}
static void __exit ghash_mod_exit(void)
{
crypto_unregister_shash(&ghash_alg);
}
module_cpu_feature_match(MSA, ghash_mod_init);
module_exit(ghash_mod_exit);
MODULE_ALIAS_CRYPTO("ghash");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");