lib/crypto: arm64/nh: Migrate optimized code into library

Migrate the arm64 NEON implementation of NH into lib/crypto/. This
makes the nh() function be optimized on arm64 kernels.

Note: this temporarily makes the adiantum template not utilize the arm64
optimized NH code. This is resolved in a later commit that converts the
adiantum template to use nh() instead of "nhpoly1305".

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Eric Biggers <[e-mail]>

arch/arm64/crypto/Kconfig

···
 	  Architecture: arm64 using:
 	  - ARMv8 Crypto Extensions
 
-config CRYPTO_NHPOLY1305_NEON
-	tristate "Hash functions: NHPoly1305 (NEON)"
-	depends on KERNEL_MODE_NEON
-	select CRYPTO_NHPOLY1305
-	help
-	  NHPoly1305 hash function (Adiantum)
-
-	  Architecture: arm64 using:
-	  - NEON (Advanced SIMD) extensions
-
 config CRYPTO_SM3_NEON
 	tristate "Hash functions: SM3 (NEON)"
 	depends on KERNEL_MODE_NEON

arch/arm64/crypto/Makefile

···
 obj-$(CONFIG_CRYPTO_AES_ARM64_NEON_BLK) += aes-neon-blk.o
 aes-neon-blk-y := aes-glue-neon.o aes-neon.o
 
-obj-$(CONFIG_CRYPTO_NHPOLY1305_NEON) += nhpoly1305-neon.o
-nhpoly1305-neon-y := nh-neon-core.o nhpoly1305-neon-glue.o
-
 obj-$(CONFIG_CRYPTO_AES_ARM64) += aes-arm64.o
 aes-arm64-y := aes-cipher-core.o aes-cipher-glue.o
 

arch/arm64/crypto/nh-neon-core.S lib/crypto/arm64/nh-neon-core.S

···
  */
 
 #include <linux/linkage.h>
-#include <linux/cfi_types.h>
 
 	KEY		.req	x0
 	MESSAGE		.req	x1
···
  *
  * It's guaranteed that message_len % 16 == 0.
  */
-SYM_TYPED_FUNC_START(nh_neon)
+SYM_FUNC_START(nh_neon)
 
 	ld1		{K0.4s,K1.4s}, [KEY], #32
 	  movi		PASS0_SUMS.2d, #0

arch/arm64/crypto/nhpoly1305-neon-glue.c

···
-// SPDX-License-Identifier: GPL-2.0
-/*
- * NHPoly1305 - ε-almost-∆-universal hash function for Adiantum
- * (ARM64 NEON accelerated version)
- *
- * Copyright 2018 Google LLC
- */
-
-#include <asm/neon.h>
-#include <asm/simd.h>
-#include <crypto/internal/hash.h>
-#include <crypto/internal/simd.h>
-#include <crypto/nhpoly1305.h>
-#include <linux/module.h>
-
-asmlinkage void nh_neon(const u32 *key, const u8 *message, size_t message_len,
-			__le64 hash[NH_NUM_PASSES]);
-
-static int nhpoly1305_neon_update(struct shash_desc *desc,
-				  const u8 *src, unsigned int srclen)
-{
-	if (srclen < 64 || !crypto_simd_usable())
-		return crypto_nhpoly1305_update(desc, src, srclen);
-
-	do {
-		unsigned int n = min_t(unsigned int, srclen, SZ_4K);
-
-		scoped_ksimd()
-			crypto_nhpoly1305_update_helper(desc, src, n, nh_neon);
-		src += n;
-		srclen -= n;
-	} while (srclen);
-	return 0;
-}
-
-static int nhpoly1305_neon_digest(struct shash_desc *desc,
-				  const u8 *src, unsigned int srclen, u8 *out)
-{
-	return crypto_nhpoly1305_init(desc) ?:
-	       nhpoly1305_neon_update(desc, src, srclen) ?:
-	       crypto_nhpoly1305_final(desc, out);
-}
-
-static struct shash_alg nhpoly1305_alg = {
-	.base.cra_name		= "nhpoly1305",
-	.base.cra_driver_name	= "nhpoly1305-neon",
-	.base.cra_priority	= 200,
-	.base.cra_ctxsize	= sizeof(struct nhpoly1305_key),
-	.base.cra_module	= THIS_MODULE,
-	.digestsize		= POLY1305_DIGEST_SIZE,
-	.init			= crypto_nhpoly1305_init,
-	.update			= nhpoly1305_neon_update,
-	.final			= crypto_nhpoly1305_final,
-	.digest			= nhpoly1305_neon_digest,
-	.setkey			= crypto_nhpoly1305_setkey,
-	.descsize		= sizeof(struct nhpoly1305_state),
-};
-
-static int __init nhpoly1305_mod_init(void)
-{
-	if (!cpu_have_named_feature(ASIMD))
-		return -ENODEV;
-
-	return crypto_register_shash(&nhpoly1305_alg);
-}
-
-static void __exit nhpoly1305_mod_exit(void)
-{
-	crypto_unregister_shash(&nhpoly1305_alg);
-}
-
-module_init(nhpoly1305_mod_init);
-module_exit(nhpoly1305_mod_exit);
-
-MODULE_DESCRIPTION("NHPoly1305 ε-almost-∆-universal hash function (NEON-accelerated)");
-MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Eric Biggers <[e-mail]>");
-MODULE_ALIAS_CRYPTO("nhpoly1305");
-MODULE_ALIAS_CRYPTO("nhpoly1305-neon");

lib/crypto/Kconfig

···
 	bool
 	depends on CRYPTO_LIB_NH && !UML
 	default y if ARM && KERNEL_MODE_NEON
+	default y if ARM64 && KERNEL_MODE_NEON
 
 config CRYPTO_LIB_POLY1305
 	tristate

lib/crypto/Makefile

···
 ifeq ($(CONFIG_CRYPTO_LIB_NH_ARCH),y)
 CFLAGS_nh.o += -I$(src)/$(SRCARCH)
 libnh-$(CONFIG_ARM) += arm/nh-neon-core.o
+libnh-$(CONFIG_ARM64) += arm64/nh-neon-core.o
 endif
 
 ################################################################################

lib/crypto/arm64/nh.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ARM64 accelerated implementation of NH
+ *
+ * Copyright 2018 Google LLC
+ */
+
+#include <asm/hwcap.h>
+#include <asm/simd.h>
+#include <linux/cpufeature.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
+
+asmlinkage void nh_neon(const u32 *key, const u8 *message, size_t message_len,
+			__le64 hash[NH_NUM_PASSES]);
+
+static bool nh_arch(const u32 *key, const u8 *message, size_t message_len,
+		    __le64 hash[NH_NUM_PASSES])
+{
+	if (static_branch_likely(&have_neon) && message_len >= 64 &&
+	    may_use_simd()) {
+		scoped_ksimd()
+			nh_neon(key, message, message_len, hash);
+		return true;
+	}
+	return false;
+}
+
+#define nh_mod_init_arch nh_mod_init_arch
+static void nh_mod_init_arch(void)
+{
+	if (cpu_have_named_feature(ASIMD))
+		static_branch_enable(&have_neon);
+}