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>

3 files changed, 86 insertions, 63 deletions

diff --git a/arch/x86/crypto/Makefile b/arch/x86/crypto/Makefile
index f307c93fc90a..c3af959648e6 100644
--- a/arch/x86/crypto/Makefile
+++ b/arch/x86/crypto/Makefile
@@ -62,7 +62,9 @@ obj-$(CONFIG_CRYPTO_SHA512_SSSE3) += sha512-ssse3.o
 sha512-ssse3-y := sha512-ssse3-asm.o sha512-avx-asm.o sha512-avx2-asm.o sha512_ssse3_glue.o
 
 obj-$(CONFIG_CRYPTO_BLAKE2S_X86) += blake2s-x86_64.o
-blake2s-x86_64-y := blake2s-core.o blake2s-glue.o
+blake2s-x86_64-y := blake2s-shash.o
+obj-$(if $(CONFIG_CRYPTO_BLAKE2S_X86),y) += libblake2s-x86_64.o
+libblake2s-x86_64-y := blake2s-core.o blake2s-glue.o
 
 obj-$(CONFIG_CRYPTO_GHASH_CLMUL_NI_INTEL) += ghash-clmulni-intel.o
 ghash-clmulni-intel-y := ghash-clmulni-intel_asm.o ghash-clmulni-intel_glue.o
diff --git a/arch/x86/crypto/blake2s-glue.c b/arch/x86/crypto/blake2s-glue.c
index a40365ab301e..69853c13e8fb 100644
--- a/arch/x86/crypto/blake2s-glue.c
+++ b/arch/x86/crypto/blake2s-glue.c
@@ -5,7 +5,6 @@
 
 #include <crypto/internal/blake2s.h>
 #include <crypto/internal/simd.h>
-#include <crypto/internal/hash.h>
 
 #include <linux/types.h>
 #include <linux/jump_label.h>
@@ -28,9 +27,8 @@ asmlinkage void blake2s_compress_avx512(struct blake2s_state *state,
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(blake2s_use_ssse3);
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(blake2s_use_avx512);
 
-void blake2s_compress_arch(struct blake2s_state *state,
-			   const u8 *block, size_t nblocks,
-			   const u32 inc)
+void blake2s_compress(struct blake2s_state *state, const u8 *block,
+		      size_t nblocks, const u32 inc)
 {
 	/* SIMD disables preemption, so relax after processing each page. */
 	BUILD_BUG_ON(SZ_4K / BLAKE2S_BLOCK_SIZE < 8);
@@ -56,49 +54,12 @@ void blake2s_compress_arch(struct blake2s_state *state,
 		block += blocks * BLAKE2S_BLOCK_SIZE;
 	} while (nblocks);
 }
-EXPORT_SYMBOL(blake2s_compress_arch);
-
-static int crypto_blake2s_update_x86(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_x86(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_x86,	\
-		.final			= crypto_blake2s_final_x86,	\
-		.descsize		= sizeof(struct blake2s_state),	\
-	}
-
-static struct shash_alg blake2s_algs[] = {
-	BLAKE2S_ALG("blake2s-128", "blake2s-128-x86", BLAKE2S_128_HASH_SIZE),
-	BLAKE2S_ALG("blake2s-160", "blake2s-160-x86", BLAKE2S_160_HASH_SIZE),
-	BLAKE2S_ALG("blake2s-224", "blake2s-224-x86", BLAKE2S_224_HASH_SIZE),
-	BLAKE2S_ALG("blake2s-256", "blake2s-256-x86", BLAKE2S_256_HASH_SIZE),
-};
+EXPORT_SYMBOL(blake2s_compress);
 
 static int __init blake2s_mod_init(void)
 {
-	if (!boot_cpu_has(X86_FEATURE_SSSE3))
-		return 0;
-
-	static_branch_enable(&blake2s_use_ssse3);
+	if (boot_cpu_has(X86_FEATURE_SSSE3))
+		static_branch_enable(&blake2s_use_ssse3);
 
 	if (IS_ENABLED(CONFIG_AS_AVX512) &&
 	    boot_cpu_has(X86_FEATURE_AVX) &&
@@ -109,26 +70,9 @@ static int __init blake2s_mod_init(void)
 			      XFEATURE_MASK_AVX512, NULL))
 		static_branch_enable(&blake2s_use_avx512);
 
-	return IS_REACHABLE(CONFIG_CRYPTO_HASH) ?
-		crypto_register_shashes(blake2s_algs,
-					ARRAY_SIZE(blake2s_algs)) : 0;
-}
-
-static void __exit blake2s_mod_exit(void)
-{
-	if (IS_REACHABLE(CONFIG_CRYPTO_HASH) && boot_cpu_has(X86_FEATURE_SSSE3))
-		crypto_unregister_shashes(blake2s_algs, ARRAY_SIZE(blake2s_algs));
+	return 0;
 }
 
 module_init(blake2s_mod_init);
-module_exit(blake2s_mod_exit);
 
-MODULE_ALIAS_CRYPTO("blake2s-128");
-MODULE_ALIAS_CRYPTO("blake2s-128-x86");
-MODULE_ALIAS_CRYPTO("blake2s-160");
-MODULE_ALIAS_CRYPTO("blake2s-160-x86");
-MODULE_ALIAS_CRYPTO("blake2s-224");
-MODULE_ALIAS_CRYPTO("blake2s-224-x86");
-MODULE_ALIAS_CRYPTO("blake2s-256");
-MODULE_ALIAS_CRYPTO("blake2s-256-x86");
 MODULE_LICENSE("GPL v2");
diff --git a/arch/x86/crypto/blake2s-shash.c b/arch/x86/crypto/blake2s-shash.c
new file mode 100644
index 000000000000..f9e2fecdb761
--- /dev/null
+++ b/arch/x86/crypto/blake2s-shash.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <crypto/internal/blake2s.h>
+#include <crypto/internal/simd.h>
+#include <crypto/internal/hash.h>
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+
+#include <asm/cpufeature.h>
+#include <asm/processor.h>
+
+static int crypto_blake2s_update_x86(struct shash_desc *desc,
+				     const u8 *in, unsigned int inlen)
+{
+	return crypto_blake2s_update(desc, in, inlen, blake2s_compress);
+}
+
+static int crypto_blake2s_final_x86(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_x86,	\
+		.final			= crypto_blake2s_final_x86,	\
+		.descsize		= sizeof(struct blake2s_state),	\
+	}
+
+static struct shash_alg blake2s_algs[] = {
+	BLAKE2S_ALG("blake2s-128", "blake2s-128-x86", BLAKE2S_128_HASH_SIZE),
+	BLAKE2S_ALG("blake2s-160", "blake2s-160-x86", BLAKE2S_160_HASH_SIZE),
+	BLAKE2S_ALG("blake2s-224", "blake2s-224-x86", BLAKE2S_224_HASH_SIZE),
+	BLAKE2S_ALG("blake2s-256", "blake2s-256-x86", BLAKE2S_256_HASH_SIZE),
+};
+
+static int __init blake2s_mod_init(void)
+{
+	if (IS_REACHABLE(CONFIG_CRYPTO_HASH) && boot_cpu_has(X86_FEATURE_SSSE3))
+		return crypto_register_shashes(blake2s_algs, ARRAY_SIZE(blake2s_algs));
+	return 0;
+}
+
+static void __exit blake2s_mod_exit(void)
+{
+	if (IS_REACHABLE(CONFIG_CRYPTO_HASH) && boot_cpu_has(X86_FEATURE_SSSE3))
+		crypto_unregister_shashes(blake2s_algs, ARRAY_SIZE(blake2s_algs));
+}
+
+module_init(blake2s_mod_init);
+module_exit(blake2s_mod_exit);
+
+MODULE_ALIAS_CRYPTO("blake2s-128");
+MODULE_ALIAS_CRYPTO("blake2s-128-x86");
+MODULE_ALIAS_CRYPTO("blake2s-160");
+MODULE_ALIAS_CRYPTO("blake2s-160-x86");
+MODULE_ALIAS_CRYPTO("blake2s-224");
+MODULE_ALIAS_CRYPTO("blake2s-224-x86");
+MODULE_ALIAS_CRYPTO("blake2s-256");
+MODULE_ALIAS_CRYPTO("blake2s-256-x86");
+MODULE_LICENSE("GPL v2");