linux_dsm_epyc7002/arch/s390/crypto/ghash_s390.c
Martin Schwidefsky 0177db01ad s390/crypto: simplify return code handling
The CPACF instructions can complete with three different condition codes:
CC=0 for successful completion, CC=1 if the protected key verification
failed, and CC=3 for partial completion.

The inline functions will restart the CPACF instruction for partial
completion, this removes the CC=3 case. The CC=1 case is only relevant
for the protected key functions of the KM, KMC, KMAC and KMCTR
instructions. As the protected key functions are not used by the
current code, there is no need for any kind of return code handling.

Reviewed-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-08-29 11:05:07 +02:00

157 lines
3.1 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(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");