crypto: s390 - add System z hardware support for GHASH
This patch adds System z hardware acceleration support for the GHASH
algorithm for GCM (Galois/Counter 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>
diff --git a/arch/s390/crypto/ghash_s390.c b/arch/s390/crypto/ghash_s390.c
new file mode 100644
index 0000000..b1bd170
--- /dev/null
+++ b/arch/s390/crypto/ghash_s390.c
@@ -0,0 +1,162 @@
+/*
+ * 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 "crypt_s390.h"
+
+#define GHASH_BLOCK_SIZE 16
+#define GHASH_DIGEST_SIZE 16
+
+struct ghash_ctx {
+ u8 icv[16];
+ u8 key[16];
+};
+
+struct ghash_desc_ctx {
+ u8 buffer[GHASH_BLOCK_SIZE];
+ u32 bytes;
+};
+
+static int ghash_init(struct shash_desc *desc)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+
+ memset(dctx, 0, sizeof(*dctx));
+
+ 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);
+ memset(ctx->icv, 0, 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);
+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ unsigned int n;
+ u8 *buf = dctx->buffer;
+ int ret;
+
+ 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) {
+ ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf,
+ GHASH_BLOCK_SIZE);
+ BUG_ON(ret != GHASH_BLOCK_SIZE);
+ }
+ }
+
+ n = srclen & ~(GHASH_BLOCK_SIZE - 1);
+ if (n) {
+ ret = crypt_s390_kimd(KIMD_GHASH, ctx, src, n);
+ BUG_ON(ret != n);
+ src += n;
+ srclen -= n;
+ }
+
+ if (srclen) {
+ dctx->bytes = GHASH_BLOCK_SIZE - srclen;
+ memcpy(buf, src, srclen);
+ }
+
+ return 0;
+}
+
+static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
+{
+ u8 *buf = dctx->buffer;
+ int ret;
+
+ if (dctx->bytes) {
+ u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+ memset(pos, 0, dctx->bytes);
+
+ ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf, GHASH_BLOCK_SIZE);
+ BUG_ON(ret != GHASH_BLOCK_SIZE);
+ }
+
+ dctx->bytes = 0;
+}
+
+static int ghash_final(struct shash_desc *desc, u8 *dst)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+
+ ghash_flush(ctx, dctx);
+ memcpy(dst, ctx->icv, GHASH_BLOCK_SIZE);
+
+ return 0;
+}
+
+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 = CRYPT_S390_PRIORITY,
+ .cra_flags = CRYPTO_ALG_TYPE_SHASH,
+ .cra_blocksize = GHASH_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct ghash_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(ghash_alg.base.cra_list),
+ },
+};
+
+static int __init ghash_mod_init(void)
+{
+ if (!crypt_s390_func_available(KIMD_GHASH,
+ CRYPT_S390_MSA | CRYPT_S390_MSA4))
+ return -EOPNOTSUPP;
+
+ return crypto_register_shash(&ghash_alg);
+}
+
+static void __exit ghash_mod_exit(void)
+{
+ crypto_unregister_shash(&ghash_alg);
+}
+
+module_init(ghash_mod_init);
+module_exit(ghash_mod_exit);
+
+MODULE_ALIAS("ghash");
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");