crypto: powerpc - convert SPE AES algorithms to skcipher API

Convert the glue code for the PowerPC SPE implementations of AES-ECB, AES-CBC, AES-CTR, and AES-XTS from the deprecated "blkcipher" API to the "skcipher" API. This is needed in order for the blkcipher API to be removed. Tested with: export ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- make mpc85xx_defconfig cat >> .config << EOF # CONFIG_MODULES is not set # CONFIG_CRYPTO_MANAGER_DISABLE_TESTS is not set CONFIG_DEBUG_KERNEL=y CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y CONFIG_CRYPTO_AES=y CONFIG_CRYPTO_CBC=y CONFIG_CRYPTO_CTR=y CONFIG_CRYPTO_ECB=y CONFIG_CRYPTO_XTS=y CONFIG_CRYPTO_AES_PPC_SPE=y EOF make olddefconfig make -j32 qemu-system-ppc -M mpc8544ds -cpu e500 -nographic \ -kernel arch/powerpc/boot/zImage \ -append cryptomgr.fuzz_iterations=1000 Note that xts-ppc-spe still fails the comparison tests due to the lack of ciphertext stealing support. This is not addressed by this patch. This patch also cleans up the code by making ->encrypt() and ->decrypt() call a common function for each of ECB, CBC, and XTS, and by using a clearer way to compute the length to process at each step. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-11-24 04:34:08 +08:00 · 2019-10-14 19:45:17 -07:00 · 2019-10-14 19:45:17 -07:00 · 7f725f41f6
commit 7f725f41f6
parent 8255e65df9
2 changed files with 168 additions and 218 deletions
--- a/arch/powerpc/crypto/aes-spe-glue.c
+++ b/arch/powerpc/crypto/aes-spe-glue.c
@ -17,6 +17,7 @@
 #include <asm/byteorder.h>
 #include <asm/switch_to.h>
 #include <crypto/algapi.h>
+#include <crypto/internal/skcipher.h>
 #include <crypto/xts.h>

 /*
@ -118,13 +119,19 @@ static int ppc_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
 	return 0;
 }

-static int ppc_xts_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+static int ppc_aes_setkey_skcipher(struct crypto_skcipher *tfm,
+				   const u8 *in_key, unsigned int key_len)
+{
+	return ppc_aes_setkey(crypto_skcipher_tfm(tfm), in_key, key_len);
+}
+
+static int ppc_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 		   unsigned int key_len)
 {
-	struct ppc_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct ppc_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	int err;

-	err = xts_check_key(tfm, in_key, key_len);
+	err = xts_verify_key(tfm, in_key, key_len);
 	if (err)
 		return err;

@ -133,7 +140,7 @@ static int ppc_xts_setkey(struct crypto_tfm *tfm, const u8 *in_key,
 	if (key_len != AES_KEYSIZE_128 &&
 	    key_len != AES_KEYSIZE_192 &&
 	    key_len != AES_KEYSIZE_256) {
-		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 		return -EINVAL;
 	}

@ -178,201 +185,154 @@ static void ppc_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 	spe_end();
 }

-static int ppc_ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			   struct scatterlist *src, unsigned int nbytes)
+static int ppc_ecb_crypt(struct skcipher_request *req, bool enc)
 {
-	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int ubytes;
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct ppc_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	unsigned int nbytes;
 	int err;

-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt(desc, &walk);
+	err = skcipher_walk_virt(&walk, req, false);

-	while ((nbytes = walk.nbytes)) {
-		ubytes = nbytes > MAX_BYTES ?
-			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
-		nbytes -= ubytes;
+	while ((nbytes = walk.nbytes) != 0) {
+		nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
+		nbytes = round_down(nbytes, AES_BLOCK_SIZE);

 		spe_begin();
-		ppc_encrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
-				ctx->key_enc, ctx->rounds, nbytes);
+		if (enc)
+			ppc_encrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
+					ctx->key_enc, ctx->rounds, nbytes);
+		else
+			ppc_decrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
+					ctx->key_dec, ctx->rounds, nbytes);
 		spe_end();

-		err = blkcipher_walk_done(desc, &walk, ubytes);
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}

 	return err;
 }

-static int ppc_ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			   struct scatterlist *src, unsigned int nbytes)
+static int ppc_ecb_encrypt(struct skcipher_request *req)
 {
-	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int ubytes;
+	return ppc_ecb_crypt(req, true);
+}
+
+static int ppc_ecb_decrypt(struct skcipher_request *req)
+{
+	return ppc_ecb_crypt(req, false);
+}
+
+static int ppc_cbc_crypt(struct skcipher_request *req, bool enc)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct ppc_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	unsigned int nbytes;
 	int err;

-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt(desc, &walk);
+	err = skcipher_walk_virt(&walk, req, false);

-	while ((nbytes = walk.nbytes)) {
-		ubytes = nbytes > MAX_BYTES ?
-			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
-		nbytes -= ubytes;
+	while ((nbytes = walk.nbytes) != 0) {
+		nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
+		nbytes = round_down(nbytes, AES_BLOCK_SIZE);

 		spe_begin();
-		ppc_decrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
-				ctx->key_dec, ctx->rounds, nbytes);
+		if (enc)
+			ppc_encrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
+					ctx->key_enc, ctx->rounds, nbytes,
+					walk.iv);
+		else
+			ppc_decrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
+					ctx->key_dec, ctx->rounds, nbytes,
+					walk.iv);
 		spe_end();

-		err = blkcipher_walk_done(desc, &walk, ubytes);
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}

 	return err;
 }

-static int ppc_cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			   struct scatterlist *src, unsigned int nbytes)
+static int ppc_cbc_encrypt(struct skcipher_request *req)
 {
-	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int ubytes;
-	int err;
-
-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt(desc, &walk);
-
-	while ((nbytes = walk.nbytes)) {
-		ubytes = nbytes > MAX_BYTES ?
-			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
-		nbytes -= ubytes;
-
-		spe_begin();
-		ppc_encrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
-				ctx->key_enc, ctx->rounds, nbytes, walk.iv);
-		spe_end();
-
-		err = blkcipher_walk_done(desc, &walk, ubytes);
-	}
-
-	return err;
+	return ppc_cbc_crypt(req, true);
 }

-static int ppc_cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			   struct scatterlist *src, unsigned int nbytes)
+static int ppc_cbc_decrypt(struct skcipher_request *req)
 {
-	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int ubytes;
-	int err;
-
-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt(desc, &walk);
-
-	while ((nbytes = walk.nbytes)) {
-		ubytes = nbytes > MAX_BYTES ?
-			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
-		nbytes -= ubytes;
-
-		spe_begin();
-		ppc_decrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
-				ctx->key_dec, ctx->rounds, nbytes, walk.iv);
-		spe_end();
-
-		err = blkcipher_walk_done(desc, &walk, ubytes);
-	}
-
-	return err;
+	return ppc_cbc_crypt(req, false);
 }

-static int ppc_ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			 struct scatterlist *src, unsigned int nbytes)
+static int ppc_ctr_crypt(struct skcipher_request *req)
 {
-	struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int pbytes, ubytes;
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct ppc_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	unsigned int nbytes;
 	int err;

-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
+	err = skcipher_walk_virt(&walk, req, false);

-	while ((pbytes = walk.nbytes)) {
-		pbytes = pbytes > MAX_BYTES ? MAX_BYTES : pbytes;
-		pbytes = pbytes == nbytes ?
-			 nbytes : pbytes & ~(AES_BLOCK_SIZE - 1);
-		ubytes = walk.nbytes - pbytes;
+	while ((nbytes = walk.nbytes) != 0) {
+		nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
+		if (nbytes < walk.total)
+			nbytes = round_down(nbytes, AES_BLOCK_SIZE);

 		spe_begin();
 		ppc_crypt_ctr(walk.dst.virt.addr, walk.src.virt.addr,
-			      ctx->key_enc, ctx->rounds, pbytes , walk.iv);
+			      ctx->key_enc, ctx->rounds, nbytes, walk.iv);
 		spe_end();

-		nbytes -= pbytes;
-		err = blkcipher_walk_done(desc, &walk, ubytes);
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}

 	return err;
 }

-static int ppc_xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			   struct scatterlist *src, unsigned int nbytes)
+static int ppc_xts_crypt(struct skcipher_request *req, bool enc)
 {
-	struct ppc_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int ubytes;
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct ppc_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	unsigned int nbytes;
 	int err;
 	u32 *twk;

-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt(desc, &walk);
+	err = skcipher_walk_virt(&walk, req, false);
 	twk = ctx->key_twk;

-	while ((nbytes = walk.nbytes)) {
-		ubytes = nbytes > MAX_BYTES ?
-			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
-		nbytes -= ubytes;
+	while ((nbytes = walk.nbytes) != 0) {
+		nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
+		nbytes = round_down(nbytes, AES_BLOCK_SIZE);

 		spe_begin();
-		ppc_encrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
-				ctx->key_enc, ctx->rounds, nbytes, walk.iv, twk);
+		if (enc)
+			ppc_encrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
+					ctx->key_enc, ctx->rounds, nbytes,
+					walk.iv, twk);
+		else
+			ppc_decrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
+					ctx->key_dec, ctx->rounds, nbytes,
+					walk.iv, twk);
 		spe_end();

 		twk = NULL;
-		err = blkcipher_walk_done(desc, &walk, ubytes);
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}

 	return err;
 }

-static int ppc_xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			   struct scatterlist *src, unsigned int nbytes)
+static int ppc_xts_encrypt(struct skcipher_request *req)
 {
-	struct ppc_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	unsigned int ubytes;
-	int err;
-	u32 *twk;
+	return ppc_xts_crypt(req, true);
+}

-	blkcipher_walk_init(&walk, dst, src, nbytes);
-	err = blkcipher_walk_virt(desc, &walk);
-	twk = ctx->key_twk;
-
-	while ((nbytes = walk.nbytes)) {
-		ubytes = nbytes > MAX_BYTES ?
-			 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
-		nbytes -= ubytes;
-
-		spe_begin();
-		ppc_decrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
-				ctx->key_dec, ctx->rounds, nbytes, walk.iv, twk);
-		spe_end();
-
-		twk = NULL;
-		err = blkcipher_walk_done(desc, &walk, ubytes);
-	}
-
-	return err;
+static int ppc_xts_decrypt(struct skcipher_request *req)
+{
+	return ppc_xts_crypt(req, false);
 }

 /*
@ -381,9 +341,9 @@ static int ppc_xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
 * This improves IPsec thoughput by another few percent. Additionally we assume
 * that AES context is always aligned to at least 8 bytes because it is created
 * with kmalloc() in the crypto infrastructure
- *
 */
-static struct crypto_alg aes_algs[] = { {
+
+static struct crypto_alg aes_cipher_alg = {
 	.cra_name		=	"aes",
 	.cra_driver_name	=	"aes-ppc-spe",
 	.cra_priority		=	300,
@ -401,95 +361,84 @@ static struct crypto_alg aes_algs[] = { {
 			.cia_decrypt		=	ppc_aes_decrypt
 		}
 	}
-}, {
-	.cra_name		=	"ecb(aes)",
-	.cra_driver_name	=	"ecb-ppc-spe",
-	.cra_priority		=	300,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
-	.cra_blocksize		=	AES_BLOCK_SIZE,
-	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
-	.cra_alignmask		=	0,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_u = {
-		.blkcipher = {
-			.min_keysize		=	AES_MIN_KEY_SIZE,
-			.max_keysize		=	AES_MAX_KEY_SIZE,
-			.setkey			=	ppc_aes_setkey,
-			.encrypt		=	ppc_ecb_encrypt,
-			.decrypt		=	ppc_ecb_decrypt,
-		}
+};
+
+static struct skcipher_alg aes_skcipher_algs[] = {
+	{
+		.base.cra_name		=	"ecb(aes)",
+		.base.cra_driver_name	=	"ecb-ppc-spe",
+		.base.cra_priority	=	300,
+		.base.cra_blocksize	=	AES_BLOCK_SIZE,
+		.base.cra_ctxsize	=	sizeof(struct ppc_aes_ctx),
+		.base.cra_module	=	THIS_MODULE,
+		.min_keysize		=	AES_MIN_KEY_SIZE,
+		.max_keysize		=	AES_MAX_KEY_SIZE,
+		.setkey			=	ppc_aes_setkey_skcipher,
+		.encrypt		=	ppc_ecb_encrypt,
+		.decrypt		=	ppc_ecb_decrypt,
+	}, {
+		.base.cra_name		=	"cbc(aes)",
+		.base.cra_driver_name	=	"cbc-ppc-spe",
+		.base.cra_priority	=	300,
+		.base.cra_blocksize	=	AES_BLOCK_SIZE,
+		.base.cra_ctxsize	=	sizeof(struct ppc_aes_ctx),
+		.base.cra_module	=	THIS_MODULE,
+		.min_keysize		=	AES_MIN_KEY_SIZE,
+		.max_keysize		=	AES_MAX_KEY_SIZE,
+		.ivsize			=	AES_BLOCK_SIZE,
+		.setkey			=	ppc_aes_setkey_skcipher,
+		.encrypt		=	ppc_cbc_encrypt,
+		.decrypt		=	ppc_cbc_decrypt,
+	}, {
+		.base.cra_name		=	"ctr(aes)",
+		.base.cra_driver_name	=	"ctr-ppc-spe",
+		.base.cra_priority	=	300,
+		.base.cra_blocksize	=	1,
+		.base.cra_ctxsize	=	sizeof(struct ppc_aes_ctx),
+		.base.cra_module	=	THIS_MODULE,
+		.min_keysize		=	AES_MIN_KEY_SIZE,
+		.max_keysize		=	AES_MAX_KEY_SIZE,
+		.ivsize			=	AES_BLOCK_SIZE,
+		.setkey			=	ppc_aes_setkey_skcipher,
+		.encrypt		=	ppc_ctr_crypt,
+		.decrypt		=	ppc_ctr_crypt,
+		.chunksize		=	AES_BLOCK_SIZE,
+	}, {
+		.base.cra_name		=	"xts(aes)",
+		.base.cra_driver_name	=	"xts-ppc-spe",
+		.base.cra_priority	=	300,
+		.base.cra_blocksize	=	AES_BLOCK_SIZE,
+		.base.cra_ctxsize	=	sizeof(struct ppc_xts_ctx),
+		.base.cra_module	=	THIS_MODULE,
+		.min_keysize		=	AES_MIN_KEY_SIZE * 2,
+		.max_keysize		=	AES_MAX_KEY_SIZE * 2,
+		.ivsize			=	AES_BLOCK_SIZE,
+		.setkey			=	ppc_xts_setkey,
+		.encrypt		=	ppc_xts_encrypt,
+		.decrypt		=	ppc_xts_decrypt,
 	}
-}, {
-	.cra_name		=	"cbc(aes)",
-	.cra_driver_name	=	"cbc-ppc-spe",
-	.cra_priority		=	300,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
-	.cra_blocksize		=	AES_BLOCK_SIZE,
-	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
-	.cra_alignmask		=	0,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_u = {
-		.blkcipher = {
-			.min_keysize		=	AES_MIN_KEY_SIZE,
-			.max_keysize		=	AES_MAX_KEY_SIZE,
-			.ivsize			=	AES_BLOCK_SIZE,
-			.setkey			=	ppc_aes_setkey,
-			.encrypt		=	ppc_cbc_encrypt,
-			.decrypt		=	ppc_cbc_decrypt,
-		}
-	}
-}, {
-	.cra_name		=	"ctr(aes)",
-	.cra_driver_name	=	"ctr-ppc-spe",
-	.cra_priority		=	300,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
-	.cra_blocksize		=	1,
-	.cra_ctxsize		=	sizeof(struct ppc_aes_ctx),
-	.cra_alignmask		=	0,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_u = {
-		.blkcipher = {
-			.min_keysize		=	AES_MIN_KEY_SIZE,
-			.max_keysize		=	AES_MAX_KEY_SIZE,
-			.ivsize			=	AES_BLOCK_SIZE,
-			.setkey			=	ppc_aes_setkey,
-			.encrypt		=	ppc_ctr_crypt,
-			.decrypt		=	ppc_ctr_crypt,
-		}
-	}
-}, {
-	.cra_name		=	"xts(aes)",
-	.cra_driver_name	=	"xts-ppc-spe",
-	.cra_priority		=	300,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
-	.cra_blocksize		=	AES_BLOCK_SIZE,
-	.cra_ctxsize		=	sizeof(struct ppc_xts_ctx),
-	.cra_alignmask		=	0,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_u = {
-		.blkcipher = {
-			.min_keysize		=	AES_MIN_KEY_SIZE * 2,
-			.max_keysize		=	AES_MAX_KEY_SIZE * 2,
-			.ivsize			=	AES_BLOCK_SIZE,
-			.setkey			=	ppc_xts_setkey,
-			.encrypt		=	ppc_xts_encrypt,
-			.decrypt		=	ppc_xts_decrypt,
-		}
-	}
-} };
+};

 static int __init ppc_aes_mod_init(void)
 {
-	return crypto_register_algs(aes_algs, ARRAY_SIZE(aes_algs));
+	int err;
+
+	err = crypto_register_alg(&aes_cipher_alg);
+	if (err)
+		return err;
+
+	err = crypto_register_skciphers(aes_skcipher_algs,
+					ARRAY_SIZE(aes_skcipher_algs));
+	if (err)
+		crypto_unregister_alg(&aes_cipher_alg);
+	return err;
 }

 static void __exit ppc_aes_mod_fini(void)
 {
-	crypto_unregister_algs(aes_algs, ARRAY_SIZE(aes_algs));
+	crypto_unregister_alg(&aes_cipher_alg);
+	crypto_unregister_skciphers(aes_skcipher_algs,
+				    ARRAY_SIZE(aes_skcipher_algs));
 }

 module_init(ppc_aes_mod_init);
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@ -1125,6 +1125,7 @@ config CRYPTO_AES_SPARC64
 config CRYPTO_AES_PPC_SPE
 	tristate "AES cipher algorithms (PPC SPE)"
 	depends on PPC && SPE
+	select CRYPTO_BLKCIPHER
 	help
 	  AES cipher algorithms (FIPS-197). Additionally the acceleration
 	  for popular block cipher modes ECB, CBC, CTR and XTS is supported.