crypto: arm64/crct10dif - register PMULL variants as separate algos

The arm64 CRC-T10DIF implementation either uses 8-bit or 64-bit
polynomial multiplication instructions, since the latter are
faster but not mandatory in the architecture.

Since that prevents us from testing both implementations on the
same system, let's expose both implementations to the crypto API,
with the priorities reflecting that the P64 version is the
preferred one if available.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm64/crypto/crct10dif-ce-glue.c

@@ -25,8 +25,6 @@
 asmlinkage u16 crc_t10dif_pmull_p64(u16 init_crc, const u8 buf[], u64 len);
 asmlinkage u16 crc_t10dif_pmull_p8(u16 init_crc, const u8 buf[], u64 len);
 
-static u16 (*crc_t10dif_pmull)(u16 init_crc, const u8 buf[], u64 len);
-
 static int crct10dif_init(struct shash_desc *desc)
 {
 	u16 *crc = shash_desc_ctx(desc);
@@ -35,14 +33,30 @@ static int crct10dif_init(struct shash_desc *desc)
 	return 0;
 }
 
-static int crct10dif_update(struct shash_desc *desc, const u8 *data,
+static int crct10dif_update_pmull_p8(struct shash_desc *desc, const u8 *data,
+			    unsigned int length)
+{
+	u16 *crc = shash_desc_ctx(desc);
+
+	if (length >= CRC_T10DIF_PMULL_CHUNK_SIZE && may_use_simd()) {
+		kernel_neon_begin();
+		*crc = crc_t10dif_pmull_p8(*crc, data, length);
+		kernel_neon_end();
+	} else {
+		*crc = crc_t10dif_generic(*crc, data, length);
+	}
+
+	return 0;
+}
+
+static int crct10dif_update_pmull_p64(struct shash_desc *desc, const u8 *data,
 			    unsigned int length)
 {
 	u16 *crc = shash_desc_ctx(desc);
 
 	if (length >= CRC_T10DIF_PMULL_CHUNK_SIZE && may_use_simd()) {
 		kernel_neon_begin();
-		*crc = crc_t10dif_pmull(*crc, data, length);
+		*crc = crc_t10dif_pmull_p64(*crc, data, length);
 		kernel_neon_end();
 	} else {
 		*crc = crc_t10dif_generic(*crc, data, length);
@@ -59,10 +73,22 @@ static int crct10dif_final(struct shash_desc *desc, u8 *out)
 	return 0;
 }
 
-static struct shash_alg crc_t10dif_alg = {
+static struct shash_alg crc_t10dif_alg[] = {{
 	.digestsize		= CRC_T10DIF_DIGEST_SIZE,
 	.init			= crct10dif_init,
-	.update			= crct10dif_update,
+	.update			= crct10dif_update_pmull_p8,
+	.final			= crct10dif_final,
+	.descsize		= CRC_T10DIF_DIGEST_SIZE,
+
+	.base.cra_name		= "crct10dif",
+	.base.cra_driver_name	= "crct10dif-arm64-neon",
+	.base.cra_priority	= 100,
+	.base.cra_blocksize	= CRC_T10DIF_BLOCK_SIZE,
+	.base.cra_module	= THIS_MODULE,
+}, {
+	.digestsize		= CRC_T10DIF_DIGEST_SIZE,
+	.init			= crct10dif_init,
+	.update			= crct10dif_update_pmull_p64,
 	.final			= crct10dif_final,
 	.descsize		= CRC_T10DIF_DIGEST_SIZE,
 
@@ -71,21 +97,25 @@ static struct shash_alg crc_t10dif_alg = {
 	.base.cra_priority	= 200,
 	.base.cra_blocksize	= CRC_T10DIF_BLOCK_SIZE,
 	.base.cra_module	= THIS_MODULE,
-};
+}};
 
 static int __init crc_t10dif_mod_init(void)
 {
 	if (elf_hwcap & HWCAP_PMULL)
-		crc_t10dif_pmull = crc_t10dif_pmull_p64;
+		return crypto_register_shashes(crc_t10dif_alg,
+					       ARRAY_SIZE(crc_t10dif_alg));
 	else
-		crc_t10dif_pmull = crc_t10dif_pmull_p8;
-
-	return crypto_register_shash(&crc_t10dif_alg);
+		/* only register the first array element */
+		return crypto_register_shash(crc_t10dif_alg);
 }
 
 static void __exit crc_t10dif_mod_exit(void)
 {
-	crypto_unregister_shash(&crc_t10dif_alg);
+	if (elf_hwcap & HWCAP_PMULL)
+		crypto_unregister_shashes(crc_t10dif_alg,
+					  ARRAY_SIZE(crc_t10dif_alg));
+	else
+		crypto_unregister_shash(crc_t10dif_alg);
 }
 
 module_cpu_feature_match(ASIMD, crc_t10dif_mod_init);