crypto: arm64/aes-neon - limit exposed routines if faster driver is enabled

The pure NEON AES implementation predates the bit-slicing one, and is
generally slower, unless the algorithm in question can only execute
sequentially.

So advertising the skciphers that the bit-slicing driver implements as
well serves no real purpose, and we can just disable them. Note that the
bit-slicing driver also has a link time dependency on the pure NEON
driver, for CBC encryption and for XTS tweak calculation, so we still
need both drivers on systems that do not implement the Crypto Extensions.

At the same time, expose those modaliases for the AES instruction based
driver. This is necessary since otherwise, we may end up loading the
wrong driver when any of the skciphers are instantiated before the CPU
capability based module loading has completed.

Finally, add the missing modalias for cts(cbc(aes)) so requests for
this algorithm will autoload the correct module.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 59 insertions, 53 deletions

diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index 2a2e0a3fc4eb..a1c4e30d76c9 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -54,15 +54,18 @@ MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
 #define aes_xts_decrypt		neon_aes_xts_decrypt
 #define aes_mac_update		neon_aes_mac_update
 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 NEON");
+#endif
+#if defined(USE_V8_CRYPTO_EXTENSIONS) || !defined(CONFIG_CRYPTO_AES_ARM64_BS)
 MODULE_ALIAS_CRYPTO("ecb(aes)");
 MODULE_ALIAS_CRYPTO("cbc(aes)");
-MODULE_ALIAS_CRYPTO("essiv(cbc(aes),sha256)");
 MODULE_ALIAS_CRYPTO("ctr(aes)");
 MODULE_ALIAS_CRYPTO("xts(aes)");
+#endif
+MODULE_ALIAS_CRYPTO("cts(cbc(aes))");
+MODULE_ALIAS_CRYPTO("essiv(cbc(aes),sha256)");
 MODULE_ALIAS_CRYPTO("cmac(aes)");
 MODULE_ALIAS_CRYPTO("xcbc(aes)");
 MODULE_ALIAS_CRYPTO("cbcmac(aes)");
-#endif
 
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 MODULE_LICENSE("GPL v2");
@@ -144,8 +147,8 @@ static int skcipher_aes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 	return ret;
 }
 
-static int xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-		       unsigned int key_len)
+static int __maybe_unused xts_set_key(struct crypto_skcipher *tfm,
+				      const u8 *in_key, unsigned int key_len)
 {
 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int ret;
@@ -165,8 +168,9 @@ static int xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
 	return -EINVAL;
 }
 
-static int essiv_cbc_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			     unsigned int key_len)
+static int __maybe_unused essiv_cbc_set_key(struct crypto_skcipher *tfm,
+					    const u8 *in_key,
+					    unsigned int key_len)
 {
 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 	SHASH_DESC_ON_STACK(desc, ctx->hash);
@@ -190,7 +194,7 @@ out:
 	return -EINVAL;
 }
 
-static int ecb_encrypt(struct skcipher_request *req)
+static int __maybe_unused ecb_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -210,7 +214,7 @@ static int ecb_encrypt(struct skcipher_request *req)
 	return err;
 }
 
-static int ecb_decrypt(struct skcipher_request *req)
+static int __maybe_unused ecb_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -248,7 +252,7 @@ static int cbc_encrypt_walk(struct skcipher_request *req,
 	return err;
 }
 
-static int cbc_encrypt(struct skcipher_request *req)
+static int __maybe_unused cbc_encrypt(struct skcipher_request *req)
 {
 	struct skcipher_walk walk;
 	int err;
@@ -277,7 +281,7 @@ static int cbc_decrypt_walk(struct skcipher_request *req,
 	return err;
 }
 
-static int cbc_decrypt(struct skcipher_request *req)
+static int __maybe_unused cbc_decrypt(struct skcipher_request *req)
 {
 	struct skcipher_walk walk;
 	int err;
@@ -404,7 +408,7 @@ static int cts_cbc_decrypt(struct skcipher_request *req)
 	return skcipher_walk_done(&walk, 0);
 }
 
-static int essiv_cbc_init_tfm(struct crypto_skcipher *tfm)
+static int __maybe_unused essiv_cbc_init_tfm(struct crypto_skcipher *tfm)
 {
 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 
@@ -413,14 +417,14 @@ static int essiv_cbc_init_tfm(struct crypto_skcipher *tfm)
 	return PTR_ERR_OR_ZERO(ctx->hash);
 }
 
-static void essiv_cbc_exit_tfm(struct crypto_skcipher *tfm)
+static void __maybe_unused essiv_cbc_exit_tfm(struct crypto_skcipher *tfm)
 {
 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 
 	crypto_free_shash(ctx->hash);
 }
 
-static int essiv_cbc_encrypt(struct skcipher_request *req)
+static int __maybe_unused essiv_cbc_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -442,7 +446,7 @@ static int essiv_cbc_encrypt(struct skcipher_request *req)
 	return err ?: cbc_encrypt_walk(req, &walk);
 }
 
-static int essiv_cbc_decrypt(struct skcipher_request *req)
+static int __maybe_unused essiv_cbc_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -518,7 +522,7 @@ static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 	local_irq_restore(flags);
 }
 
-static int ctr_encrypt_sync(struct skcipher_request *req)
+static int __maybe_unused ctr_encrypt_sync(struct skcipher_request *req)
 {
 	if (!crypto_simd_usable())
 		return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
@@ -526,7 +530,7 @@ static int ctr_encrypt_sync(struct skcipher_request *req)
 	return ctr_encrypt(req);
 }
 
-static int xts_encrypt(struct skcipher_request *req)
+static int __maybe_unused xts_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -548,7 +552,7 @@ static int xts_encrypt(struct skcipher_request *req)
 	return err;
 }
 
-static int xts_decrypt(struct skcipher_request *req)
+static int __maybe_unused xts_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -571,6 +575,7 @@ static int xts_decrypt(struct skcipher_request *req)
 }
 
 static struct skcipher_alg aes_algs[] = { {
+#if defined(USE_V8_CRYPTO_EXTENSIONS) || !defined(CONFIG_CRYPTO_AES_ARM64_BS)
 	.base = {
 		.cra_name		= "__ecb(aes)",
 		.cra_driver_name	= "__ecb-aes-" MODE,
@@ -603,42 +608,6 @@ static struct skcipher_alg aes_algs[] = { {
 	.decrypt	= cbc_decrypt,
 }, {
 	.base = {
-		.cra_name		= "__cts(cbc(aes))",
-		.cra_driver_name	= "__cts-cbc-aes-" MODE,
-		.cra_priority		= PRIO,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
-		.cra_blocksize		= AES_BLOCK_SIZE,
-		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
-		.cra_module		= THIS_MODULE,
-	},
-	.min_keysize	= AES_MIN_KEY_SIZE,
-	.max_keysize	= AES_MAX_KEY_SIZE,
-	.ivsize		= AES_BLOCK_SIZE,
-	.walksize	= 2 * AES_BLOCK_SIZE,
-	.setkey		= skcipher_aes_setkey,
-	.encrypt	= cts_cbc_encrypt,
-	.decrypt	= cts_cbc_decrypt,
-	.init		= cts_cbc_init_tfm,
-}, {
-	.base = {
-		.cra_name		= "__essiv(cbc(aes),sha256)",
-		.cra_driver_name	= "__essiv-cbc-aes-sha256-" MODE,
-		.cra_priority		= PRIO + 1,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
-		.cra_blocksize		= AES_BLOCK_SIZE,
-		.cra_ctxsize		= sizeof(struct crypto_aes_essiv_cbc_ctx),
-		.cra_module		= THIS_MODULE,
-	},
-	.min_keysize	= AES_MIN_KEY_SIZE,
-	.max_keysize	= AES_MAX_KEY_SIZE,
-	.ivsize		= AES_BLOCK_SIZE,
-	.setkey		= essiv_cbc_set_key,
-	.encrypt	= essiv_cbc_encrypt,
-	.decrypt	= essiv_cbc_decrypt,
-	.init		= essiv_cbc_init_tfm,
-	.exit		= essiv_cbc_exit_tfm,
-}, {
-	.base = {
 		.cra_name		= "__ctr(aes)",
 		.cra_driver_name	= "__ctr-aes-" MODE,
 		.cra_priority		= PRIO,
@@ -686,6 +655,43 @@ static struct skcipher_alg aes_algs[] = { {
 	.setkey		= xts_set_key,
 	.encrypt	= xts_encrypt,
 	.decrypt	= xts_decrypt,
+}, {
+#endif
+	.base = {
+		.cra_name		= "__cts(cbc(aes))",
+		.cra_driver_name	= "__cts-cbc-aes-" MODE,
+		.cra_priority		= PRIO,
+		.cra_flags		= CRYPTO_ALG_INTERNAL,
+		.cra_blocksize		= AES_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
+		.cra_module		= THIS_MODULE,
+	},
+	.min_keysize	= AES_MIN_KEY_SIZE,
+	.max_keysize	= AES_MAX_KEY_SIZE,
+	.ivsize		= AES_BLOCK_SIZE,
+	.walksize	= 2 * AES_BLOCK_SIZE,
+	.setkey		= skcipher_aes_setkey,
+	.encrypt	= cts_cbc_encrypt,
+	.decrypt	= cts_cbc_decrypt,
+	.init		= cts_cbc_init_tfm,
+}, {
+	.base = {
+		.cra_name		= "__essiv(cbc(aes),sha256)",
+		.cra_driver_name	= "__essiv-cbc-aes-sha256-" MODE,
+		.cra_priority		= PRIO + 1,
+		.cra_flags		= CRYPTO_ALG_INTERNAL,
+		.cra_blocksize		= AES_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct crypto_aes_essiv_cbc_ctx),
+		.cra_module		= THIS_MODULE,
+	},
+	.min_keysize	= AES_MIN_KEY_SIZE,
+	.max_keysize	= AES_MAX_KEY_SIZE,
+	.ivsize		= AES_BLOCK_SIZE,
+	.setkey		= essiv_cbc_set_key,
+	.encrypt	= essiv_cbc_encrypt,
+	.decrypt	= essiv_cbc_decrypt,
+	.init		= essiv_cbc_init_tfm,
+	.exit		= essiv_cbc_exit_tfm,
 } };
 
 static int cbcmac_setkey(struct crypto_shash *tfm, const u8 *in_key,