crypto: qce - support zero length test vectors

crypto test module passes zero length vectors as test input to sha-1 and
sha-256. To provide correct output for these vectors, hash zero support
has been added as in other crypto drivers.
Signed-off-by: Sivaprakash Murugesan <sivaprak@codeaurora.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/Kconfig

@@ -624,6 +624,8 @@ config CRYPTO_DEV_QCE_SKCIPHER
 config CRYPTO_DEV_QCE_SHA
 	bool
 	depends on CRYPTO_DEV_QCE
+	select CRYPTO_SHA1
+	select CRYPTO_SHA256
 
 choice
 	prompt "Algorithms enabled for QCE acceleration"

drivers/crypto/qce/common.h

@@ -87,6 +87,8 @@ struct qce_alg_template {
 		struct ahash_alg ahash;
 	} alg;
 	struct qce_device *qce;
+	const u8 *hash_zero;
+	const u32 digest_size;
 };
 
 void qce_cpu_to_be32p_array(__be32 *dst, const u8 *src, unsigned int len);

drivers/crypto/qce/sha.c

@@ -305,8 +305,12 @@ static int qce_ahash_final(struct ahash_request *req)
 	struct qce_alg_template *tmpl = to_ahash_tmpl(req->base.tfm);
 	struct qce_device *qce = tmpl->qce;
 
-	if (!rctx->buflen)
+	if (!rctx->buflen) {
+		if (tmpl->hash_zero)
+			memcpy(req->result, tmpl->hash_zero,
+					tmpl->alg.ahash.halg.digestsize);
 		return 0;
+	}
 
 	rctx->last_blk = true;
 
@@ -338,6 +342,13 @@ static int qce_ahash_digest(struct ahash_request *req)
 	rctx->first_blk = true;
 	rctx->last_blk = true;
 
+	if (!rctx->nbytes_orig) {
+		if (tmpl->hash_zero)
+			memcpy(req->result, tmpl->hash_zero,
+					tmpl->alg.ahash.halg.digestsize);
+		return 0;
+	}
+
 	return qce->async_req_enqueue(tmpl->qce, &req->base);
 }
 
@@ -490,6 +501,11 @@ static int qce_ahash_register_one(const struct qce_ahash_def *def,
 	alg->halg.digestsize = def->digestsize;
 	alg->halg.statesize = def->statesize;
 
+	if (IS_SHA1(def->flags))
+		tmpl->hash_zero = sha1_zero_message_hash;
+	else if (IS_SHA256(def->flags))
+		tmpl->hash_zero = sha256_zero_message_hash;
+
 	base = &alg->halg.base;
 	base->cra_blocksize = def->blocksize;
 	base->cra_priority = 300;