lib/crypto: blake2s: include as built-in

In preparation for using blake2s in the RNG, we change the way that it
is wired-in to the build system. Instead of using ifdefs to select the
right symbol, we use weak symbols. And because ARM doesn't need the
generic implementation, we make the generic one default only if an arch
library doesn't need it already, and then have arch libraries that do
need it opt-in. So that the arch libraries can remain tristate rather
than bool, we then split the shash part from the glue code.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

4 files changed, 83 insertions, 77 deletions

diff --git a/arch/arm/crypto/Makefile b/arch/arm/crypto/Makefile
index eafa898ba6a7..0274f81cc8ea 100644
--- a/arch/arm/crypto/Makefile
+++ b/arch/arm/crypto/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_CRYPTO_SHA1_ARM_NEON) += sha1-arm-neon.o
 obj-$(CONFIG_CRYPTO_SHA256_ARM) += sha256-arm.o
 obj-$(CONFIG_CRYPTO_SHA512_ARM) += sha512-arm.o
 obj-$(CONFIG_CRYPTO_BLAKE2S_ARM) += blake2s-arm.o
+obj-$(if $(CONFIG_CRYPTO_BLAKE2S_ARM),y) += libblake2s-arm.o
 obj-$(CONFIG_CRYPTO_BLAKE2B_NEON) += blake2b-neon.o
 obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha-neon.o
 obj-$(CONFIG_CRYPTO_POLY1305_ARM) += poly1305-arm.o
@@ -31,7 +32,8 @@ sha256-arm-neon-$(CONFIG_KERNEL_MODE_NEON) := sha256_neon_glue.o
 sha256-arm-y	:= sha256-core.o sha256_glue.o $(sha256-arm-neon-y)
 sha512-arm-neon-$(CONFIG_KERNEL_MODE_NEON) := sha512-neon-glue.o
 sha512-arm-y	:= sha512-core.o sha512-glue.o $(sha512-arm-neon-y)
-blake2s-arm-y   := blake2s-core.o blake2s-glue.o
+blake2s-arm-y   := blake2s-shash.o
+libblake2s-arm-y:= blake2s-core.o blake2s-glue.o
 blake2b-neon-y  := blake2b-neon-core.o blake2b-neon-glue.o
 sha1-arm-ce-y	:= sha1-ce-core.o sha1-ce-glue.o
 sha2-arm-ce-y	:= sha2-ce-core.o sha2-ce-glue.o
diff --git a/arch/arm/crypto/blake2s-core.S b/arch/arm/crypto/blake2s-core.S
index 86345751bbf3..df40e46601f1 100644
--- a/arch/arm/crypto/blake2s-core.S
+++ b/arch/arm/crypto/blake2s-core.S
@@ -167,8 +167,8 @@
 .endm
 
 //
-// void blake2s_compress_arch(struct blake2s_state *state,
-//			      const u8 *block, size_t nblocks, u32 inc);
+// void blake2s_compress(struct blake2s_state *state,
+//			 const u8 *block, size_t nblocks, u32 inc);
 //
 // Only the first three fields of struct blake2s_state are used:
 //	u32 h[8];	(inout)
@@ -176,7 +176,7 @@
 //	u32 f[2];	(in)
 //
 	.align		5
-ENTRY(blake2s_compress_arch)
+ENTRY(blake2s_compress)
 	push		{r0-r2,r4-r11,lr}	// keep this an even number
 
 .Lnext_block:
@@ -303,4 +303,4 @@ ENTRY(blake2s_compress_arch)
 	str		r3, [r12], #4
 	bne		1b
 	b		.Lcopy_block_done
-ENDPROC(blake2s_compress_arch)
+ENDPROC(blake2s_compress)
diff --git a/arch/arm/crypto/blake2s-glue.c b/arch/arm/crypto/blake2s-glue.c
index f2cc1e5fc9ec..0238a70d9581 100644
--- a/arch/arm/crypto/blake2s-glue.c
+++ b/arch/arm/crypto/blake2s-glue.c
@@ -1,78 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * BLAKE2s digest algorithm, ARM scalar implementation
- *
- * Copyright 2020 Google LLC
- */
 
 #include <crypto/internal/blake2s.h>
-#include <crypto/internal/hash.h>
-
 #include <linux/module.h>
 
 /* defined in blake2s-core.S */
-EXPORT_SYMBOL(blake2s_compress_arch);
-
-static int crypto_blake2s_update_arm(struct shash_desc *desc,
-				     const u8 *in, unsigned int inlen)
-{
-	return crypto_blake2s_update(desc, in, inlen, blake2s_compress_arch);
-}
-
-static int crypto_blake2s_final_arm(struct shash_desc *desc, u8 *out)
-{
-	return crypto_blake2s_final(desc, out, blake2s_compress_arch);
-}
-
-#define BLAKE2S_ALG(name, driver_name, digest_size)			\
-	{								\
-		.base.cra_name		= name,				\
-		.base.cra_driver_name	= driver_name,			\
-		.base.cra_priority	= 200,				\
-		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,	\
-		.base.cra_blocksize	= BLAKE2S_BLOCK_SIZE,		\
-		.base.cra_ctxsize	= sizeof(struct blake2s_tfm_ctx), \
-		.base.cra_module	= THIS_MODULE,			\
-		.digestsize		= digest_size,			\
-		.setkey			= crypto_blake2s_setkey,	\
-		.init			= crypto_blake2s_init,		\
-		.update			= crypto_blake2s_update_arm,	\
-		.final			= crypto_blake2s_final_arm,	\
-		.descsize		= sizeof(struct blake2s_state),	\
-	}
-
-static struct shash_alg blake2s_arm_algs[] = {
-	BLAKE2S_ALG("blake2s-128", "blake2s-128-arm", BLAKE2S_128_HASH_SIZE),
-	BLAKE2S_ALG("blake2s-160", "blake2s-160-arm", BLAKE2S_160_HASH_SIZE),
-	BLAKE2S_ALG("blake2s-224", "blake2s-224-arm", BLAKE2S_224_HASH_SIZE),
-	BLAKE2S_ALG("blake2s-256", "blake2s-256-arm", BLAKE2S_256_HASH_SIZE),
-};
-
-static int __init blake2s_arm_mod_init(void)
-{
-	return IS_REACHABLE(CONFIG_CRYPTO_HASH) ?
-		crypto_register_shashes(blake2s_arm_algs,
-					ARRAY_SIZE(blake2s_arm_algs)) : 0;
-}
-
-static void __exit blake2s_arm_mod_exit(void)
-{
-	if (IS_REACHABLE(CONFIG_CRYPTO_HASH))
-		crypto_unregister_shashes(blake2s_arm_algs,
-					  ARRAY_SIZE(blake2s_arm_algs));
-}
-
-module_init(blake2s_arm_mod_init);
-module_exit(blake2s_arm_mod_exit);
-
-MODULE_DESCRIPTION("BLAKE2s digest algorithm, ARM scalar implementation");
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
-MODULE_ALIAS_CRYPTO("blake2s-128");
-MODULE_ALIAS_CRYPTO("blake2s-128-arm");
-MODULE_ALIAS_CRYPTO("blake2s-160");
-MODULE_ALIAS_CRYPTO("blake2s-160-arm");
-MODULE_ALIAS_CRYPTO("blake2s-224");
-MODULE_ALIAS_CRYPTO("blake2s-224-arm");
-MODULE_ALIAS_CRYPTO("blake2s-256");
-MODULE_ALIAS_CRYPTO("blake2s-256-arm");
+EXPORT_SYMBOL(blake2s_compress);
diff --git a/arch/arm/crypto/blake2s-shash.c b/arch/arm/crypto/blake2s-shash.c
new file mode 100644
index 000000000000..17c1c3bfe2f5
--- /dev/null
+++ b/arch/arm/crypto/blake2s-shash.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * BLAKE2s digest algorithm, ARM scalar implementation
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <crypto/internal/blake2s.h>
+#include <crypto/internal/hash.h>
+
+#include <linux/module.h>
+
+static int crypto_blake2s_update_arm(struct shash_desc *desc,
+				     const u8 *in, unsigned int inlen)
+{
+	return crypto_blake2s_update(desc, in, inlen, blake2s_compress);
+}
+
+static int crypto_blake2s_final_arm(struct shash_desc *desc, u8 *out)
+{
+	return crypto_blake2s_final(desc, out, blake2s_compress);
+}
+
+#define BLAKE2S_ALG(name, driver_name, digest_size)			\
+	{								\
+		.base.cra_name		= name,				\
+		.base.cra_driver_name	= driver_name,			\
+		.base.cra_priority	= 200,				\
+		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,	\
+		.base.cra_blocksize	= BLAKE2S_BLOCK_SIZE,		\
+		.base.cra_ctxsize	= sizeof(struct blake2s_tfm_ctx), \
+		.base.cra_module	= THIS_MODULE,			\
+		.digestsize		= digest_size,			\
+		.setkey			= crypto_blake2s_setkey,	\
+		.init			= crypto_blake2s_init,		\
+		.update			= crypto_blake2s_update_arm,	\
+		.final			= crypto_blake2s_final_arm,	\
+		.descsize		= sizeof(struct blake2s_state),	\
+	}
+
+static struct shash_alg blake2s_arm_algs[] = {
+	BLAKE2S_ALG("blake2s-128", "blake2s-128-arm", BLAKE2S_128_HASH_SIZE),
+	BLAKE2S_ALG("blake2s-160", "blake2s-160-arm", BLAKE2S_160_HASH_SIZE),
+	BLAKE2S_ALG("blake2s-224", "blake2s-224-arm", BLAKE2S_224_HASH_SIZE),
+	BLAKE2S_ALG("blake2s-256", "blake2s-256-arm", BLAKE2S_256_HASH_SIZE),
+};
+
+static int __init blake2s_arm_mod_init(void)
+{
+	return IS_REACHABLE(CONFIG_CRYPTO_HASH) ?
+		crypto_register_shashes(blake2s_arm_algs,
+					ARRAY_SIZE(blake2s_arm_algs)) : 0;
+}
+
+static void __exit blake2s_arm_mod_exit(void)
+{
+	if (IS_REACHABLE(CONFIG_CRYPTO_HASH))
+		crypto_unregister_shashes(blake2s_arm_algs,
+					  ARRAY_SIZE(blake2s_arm_algs));
+}
+
+module_init(blake2s_arm_mod_init);
+module_exit(blake2s_arm_mod_exit);
+
+MODULE_DESCRIPTION("BLAKE2s digest algorithm, ARM scalar implementation");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
+MODULE_ALIAS_CRYPTO("blake2s-128");
+MODULE_ALIAS_CRYPTO("blake2s-128-arm");
+MODULE_ALIAS_CRYPTO("blake2s-160");
+MODULE_ALIAS_CRYPTO("blake2s-160-arm");
+MODULE_ALIAS_CRYPTO("blake2s-224");
+MODULE_ALIAS_CRYPTO("blake2s-224-arm");
+MODULE_ALIAS_CRYPTO("blake2s-256");
+MODULE_ALIAS_CRYPTO("blake2s-256-arm");