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

Eric Biggers · Eric Biggers · commit b4a8528d17fb · 2026-01-12T11:07:50.000-08:00
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/20251211011846.8179-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org>
diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
@@ -15,16 +15,6 @@ config CRYPTO_GHASH_ARM64_CE
 	  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
diff --git a/arch/arm64/crypto/Makefile b/arch/arm64/crypto/Makefile
@@ -41,9 +41,6 @@ aes-ce-blk-y := aes-glue-ce.o aes-ce.o
 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
 
diff --git a/arch/arm64/crypto/nhpoly1305-neon-glue.c b/arch/arm64/crypto/nhpoly1305-neon-glue.c
diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
@@ -118,6 +118,7 @@ config CRYPTO_LIB_NH_ARCH
 	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
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
@@ -136,6 +136,7 @@ libnh-y := nh.o
 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
 
 ################################################################################
diff --git a/lib/crypto/arm64/nh-neon-core.S b/lib/crypto/arm64/nh-neon-core.S
@@ -8,7 +8,6 @@
  */
 
 #include <linux/linkage.h>
-#include <linux/cfi_types.h>
 
 	KEY		.req	x0
 	MESSAGE		.req	x1
@@ -63,7 +62,7 @@
  *
  * 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
diff --git a/lib/crypto/arm64/nh.h b/lib/crypto/arm64/nh.h
@@ -0,0 +1,34 @@
+/* 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);
+}
