lib/crypto: arm/sha1: Migrate optimized code into library

Instead of exposing the arm-optimized SHA-1 code via arm-specific
crypto_shash algorithms, instead just implement the sha1_blocks()
library function.  This is much simpler, it makes the SHA-1 library
functions be arm-optimized, and it fixes the longstanding issue where
the arm-optimized SHA-1 code was disabled by default.  SHA-1 still
remains available through crypto_shash, but individual architectures no
longer need to handle it.

To match sha1_blocks(), change the type of the nblocks parameter of the
assembly functions from int to size_t.  The assembly functions actually
already treated it as size_t.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250712232329.818226-8-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

arch/arm/configs/exynos_defconfig

@@ -363,7 +363,6 @@ CONFIG_CRYPTO_USER_API_HASH=m
 CONFIG_CRYPTO_USER_API_SKCIPHER=m
 CONFIG_CRYPTO_USER_API_RNG=m
 CONFIG_CRYPTO_USER_API_AEAD=m
-CONFIG_CRYPTO_SHA1_ARM_NEON=m
 CONFIG_CRYPTO_AES_ARM_BS=m
 CONFIG_CRYPTO_CHACHA20_NEON=m
 CONFIG_CRYPTO_DEV_EXYNOS_RNG=y

arch/arm/configs/milbeaut_m10v_defconfig

@@ -98,8 +98,6 @@ CONFIG_CRYPTO_SELFTESTS=y
 CONFIG_CRYPTO_AES=y
 CONFIG_CRYPTO_SEQIV=m
 CONFIG_CRYPTO_GHASH_ARM_CE=m
-CONFIG_CRYPTO_SHA1_ARM_NEON=m
-CONFIG_CRYPTO_SHA1_ARM_CE=m
 CONFIG_CRYPTO_AES_ARM=m
 CONFIG_CRYPTO_AES_ARM_BS=m
 CONFIG_CRYPTO_AES_ARM_CE=m

arch/arm/configs/multi_v7_defconfig

@@ -1280,8 +1280,6 @@ CONFIG_CRYPTO_USER_API_SKCIPHER=m
 CONFIG_CRYPTO_USER_API_RNG=m
 CONFIG_CRYPTO_USER_API_AEAD=m
 CONFIG_CRYPTO_GHASH_ARM_CE=m
-CONFIG_CRYPTO_SHA1_ARM_NEON=m
-CONFIG_CRYPTO_SHA1_ARM_CE=m
 CONFIG_CRYPTO_AES_ARM=m
 CONFIG_CRYPTO_AES_ARM_BS=m
 CONFIG_CRYPTO_AES_ARM_CE=m

arch/arm/configs/omap2plus_defconfig

@@ -704,7 +704,6 @@ CONFIG_NLS_ISO8859_1=y
 CONFIG_SECURITY=y
 CONFIG_CRYPTO_MICHAEL_MIC=y
 CONFIG_CRYPTO_GHASH_ARM_CE=m
-CONFIG_CRYPTO_SHA1_ARM_NEON=m
 CONFIG_CRYPTO_AES_ARM=m
 CONFIG_CRYPTO_AES_ARM_BS=m
 CONFIG_CRYPTO_CHACHA20_NEON=m

arch/arm/configs/pxa_defconfig

@@ -658,7 +658,6 @@ CONFIG_CRYPTO_ANUBIS=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_DEFLATE=y
 CONFIG_CRYPTO_LZO=y
-CONFIG_CRYPTO_SHA1_ARM=m
 CONFIG_CRYPTO_AES_ARM=m
 CONFIG_FONTS=y
 CONFIG_FONT_8x8=y

arch/arm/crypto/Kconfig

@@ -62,37 +62,6 @@ config CRYPTO_BLAKE2B_NEON
 	  much faster than the SHA-2 family and slightly faster than
 	  SHA-1.
 
-config CRYPTO_SHA1_ARM
-	tristate "Hash functions: SHA-1"
-	select CRYPTO_SHA1
-	select CRYPTO_HASH
-	help
-	  SHA-1 secure hash algorithm (FIPS 180)
-
-	  Architecture: arm
-
-config CRYPTO_SHA1_ARM_NEON
-	tristate "Hash functions: SHA-1 (NEON)"
-	depends on KERNEL_MODE_NEON
-	select CRYPTO_SHA1_ARM
-	select CRYPTO_SHA1
-	select CRYPTO_HASH
-	help
-	  SHA-1 secure hash algorithm (FIPS 180)
-
-	  Architecture: arm using
-	  - NEON (Advanced SIMD) extensions
-
-config CRYPTO_SHA1_ARM_CE
-	tristate "Hash functions: SHA-1 (ARMv8 Crypto Extensions)"
-	depends on KERNEL_MODE_NEON
-	select CRYPTO_SHA1_ARM
-	select CRYPTO_HASH
-	help
-	  SHA-1 secure hash algorithm (FIPS 180)
-
-	  Architecture: arm using ARMv8 Crypto Extensions
-
 config CRYPTO_AES_ARM
 	tristate "Ciphers: AES"
 	select CRYPTO_ALGAPI

arch/arm/crypto/Makefile

@@ -5,22 +5,16 @@
 
 obj-$(CONFIG_CRYPTO_AES_ARM) += aes-arm.o
 obj-$(CONFIG_CRYPTO_AES_ARM_BS) += aes-arm-bs.o
-obj-$(CONFIG_CRYPTO_SHA1_ARM) += sha1-arm.o
-obj-$(CONFIG_CRYPTO_SHA1_ARM_NEON) += sha1-arm-neon.o
 obj-$(CONFIG_CRYPTO_BLAKE2B_NEON) += blake2b-neon.o
 obj-$(CONFIG_CRYPTO_NHPOLY1305_NEON) += nhpoly1305-neon.o
 obj-$(CONFIG_CRYPTO_CURVE25519_NEON) += curve25519-neon.o
 
 obj-$(CONFIG_CRYPTO_AES_ARM_CE) += aes-arm-ce.o
-obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o
 obj-$(CONFIG_CRYPTO_GHASH_ARM_CE) += ghash-arm-ce.o
 
 aes-arm-y	:= aes-cipher-core.o aes-cipher-glue.o
 aes-arm-bs-y	:= aes-neonbs-core.o aes-neonbs-glue.o
-sha1-arm-y	:= sha1-armv4-large.o sha1_glue.o
-sha1-arm-neon-y	:= sha1-armv7-neon.o sha1_neon_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
 aes-arm-ce-y	:= aes-ce-core.o aes-ce-glue.o
 ghash-arm-ce-y	:= ghash-ce-core.o ghash-ce-glue.o
 nhpoly1305-neon-y := nh-neon-core.o nhpoly1305-neon-glue.o

arch/arm/crypto/sha1-ce-glue.c

@@ -1,72 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * sha1-ce-glue.c - SHA-1 secure hash using ARMv8 Crypto Extensions
- *
- * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
- */
-
-#include <asm/neon.h>
-#include <crypto/internal/hash.h>
-#include <crypto/sha1.h>
-#include <crypto/sha1_base.h>
-#include <linux/cpufeature.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-
-MODULE_DESCRIPTION("SHA1 secure hash using ARMv8 Crypto Extensions");
-MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
-MODULE_LICENSE("GPL v2");
-
-asmlinkage void sha1_ce_transform(struct sha1_state *sst, u8 const *src,
-				  int blocks);
-
-static int sha1_ce_update(struct shash_desc *desc, const u8 *data,
-			  unsigned int len)
-{
-	int remain;
-
-	kernel_neon_begin();
-	remain = sha1_base_do_update_blocks(desc, data, len, sha1_ce_transform);
-	kernel_neon_end();
-
-	return remain;
-}
-
-static int sha1_ce_finup(struct shash_desc *desc, const u8 *data,
-			 unsigned int len, u8 *out)
-{
-	kernel_neon_begin();
-	sha1_base_do_finup(desc, data, len, sha1_ce_transform);
-	kernel_neon_end();
-
-	return sha1_base_finish(desc, out);
-}
-
-static struct shash_alg alg = {
-	.init			= sha1_base_init,
-	.update			= sha1_ce_update,
-	.finup			= sha1_ce_finup,
-	.descsize		= SHA1_STATE_SIZE,
-	.digestsize		= SHA1_DIGEST_SIZE,
-	.base			= {
-		.cra_name		= "sha1",
-		.cra_driver_name	= "sha1-ce",
-		.cra_priority		= 200,
-		.cra_flags		= CRYPTO_AHASH_ALG_BLOCK_ONLY,
-		.cra_blocksize		= SHA1_BLOCK_SIZE,
-		.cra_module		= THIS_MODULE,
-	}
-};
-
-static int __init sha1_ce_mod_init(void)
-{
-	return crypto_register_shash(&alg);
-}
-
-static void __exit sha1_ce_mod_fini(void)
-{
-	crypto_unregister_shash(&alg);
-}
-
-module_cpu_feature_match(SHA1, sha1_ce_mod_init);
-module_exit(sha1_ce_mod_fini);

arch/arm/crypto/sha1_glue.c

@@ -1,75 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Cryptographic API.
- * Glue code for the SHA1 Secure Hash Algorithm assembler implementation
- *
- * This file is based on sha1_generic.c and sha1_ssse3_glue.c
- *
- * Copyright (c) Alan Smithee.
- * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
- * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
- * Copyright (c) Mathias Krause <minipli@googlemail.com>
- */
-
-#include <crypto/internal/hash.h>
-#include <crypto/sha1.h>
-#include <crypto/sha1_base.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-
-asmlinkage void sha1_block_data_order(struct sha1_state *digest,
-		const u8 *data, int rounds);
-
-static int sha1_update_arm(struct shash_desc *desc, const u8 *data,
-			   unsigned int len)
-{
-	/* make sure signature matches sha1_block_fn() */
-	BUILD_BUG_ON(offsetof(struct sha1_state, state) != 0);
-
-	return sha1_base_do_update_blocks(desc, data, len,
-					  sha1_block_data_order);
-}
-
-static int sha1_finup_arm(struct shash_desc *desc, const u8 *data,
-			  unsigned int len, u8 *out)
-{
-	sha1_base_do_finup(desc, data, len, sha1_block_data_order);
-	return sha1_base_finish(desc, out);
-}
-
-static struct shash_alg alg = {
-	.digestsize	=	SHA1_DIGEST_SIZE,
-	.init		=	sha1_base_init,
-	.update		=	sha1_update_arm,
-	.finup		=	sha1_finup_arm,
-	.descsize	=	SHA1_STATE_SIZE,
-	.base		=	{
-		.cra_name	=	"sha1",
-		.cra_driver_name=	"sha1-asm",
-		.cra_priority	=	150,
-		.cra_flags	=	CRYPTO_AHASH_ALG_BLOCK_ONLY,
-		.cra_blocksize	=	SHA1_BLOCK_SIZE,
-		.cra_module	=	THIS_MODULE,
-	}
-};
-
-
-static int __init sha1_mod_init(void)
-{
-	return crypto_register_shash(&alg);
-}
-
-
-static void __exit sha1_mod_fini(void)
-{
-	crypto_unregister_shash(&alg);
-}
-
-
-module_init(sha1_mod_init);
-module_exit(sha1_mod_fini);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm (ARM)");
-MODULE_ALIAS_CRYPTO("sha1");
-MODULE_AUTHOR("David McCullough <ucdevel@gmail.com>");

arch/arm/crypto/sha1_neon_glue.c

@@ -1,83 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Glue code for the SHA1 Secure Hash Algorithm assembler implementation using
- * ARM NEON instructions.
- *
- * Copyright © 2014 Jussi Kivilinna <jussi.kivilinna@iki.fi>
- *
- * This file is based on sha1_generic.c and sha1_ssse3_glue.c:
- *  Copyright (c) Alan Smithee.
- *  Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
- *  Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
- *  Copyright (c) Mathias Krause <minipli@googlemail.com>
- *  Copyright (c) Chandramouli Narayanan <mouli@linux.intel.com>
- */
-
-#include <asm/neon.h>
-#include <crypto/internal/hash.h>
-#include <crypto/sha1.h>
-#include <crypto/sha1_base.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-
-asmlinkage void sha1_transform_neon(struct sha1_state *state_h,
-				    const u8 *data, int rounds);
-
-static int sha1_neon_update(struct shash_desc *desc, const u8 *data,
-			  unsigned int len)
-{
-	int remain;
-
-	kernel_neon_begin();
-	remain = sha1_base_do_update_blocks(desc, data, len,
-					    sha1_transform_neon);
-	kernel_neon_end();
-
-	return remain;
-}
-
-static int sha1_neon_finup(struct shash_desc *desc, const u8 *data,
-			   unsigned int len, u8 *out)
-{
-	kernel_neon_begin();
-	sha1_base_do_finup(desc, data, len, sha1_transform_neon);
-	kernel_neon_end();
-
-	return sha1_base_finish(desc, out);
-}
-
-static struct shash_alg alg = {
-	.digestsize	=	SHA1_DIGEST_SIZE,
-	.init		=	sha1_base_init,
-	.update		=	sha1_neon_update,
-	.finup		=	sha1_neon_finup,
-	.descsize		= SHA1_STATE_SIZE,
-	.base		=	{
-		.cra_name		= "sha1",
-		.cra_driver_name	= "sha1-neon",
-		.cra_priority		= 250,
-		.cra_flags		= CRYPTO_AHASH_ALG_BLOCK_ONLY,
-		.cra_blocksize		= SHA1_BLOCK_SIZE,
-		.cra_module		= THIS_MODULE,
-	}
-};
-
-static int __init sha1_neon_mod_init(void)
-{
-	if (!cpu_has_neon())
-		return -ENODEV;
-
-	return crypto_register_shash(&alg);
-}
-
-static void __exit sha1_neon_mod_fini(void)
-{
-	crypto_unregister_shash(&alg);
-}
-
-module_init(sha1_neon_mod_init);
-module_exit(sha1_neon_mod_fini);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm, NEON accelerated");
-MODULE_ALIAS_CRYPTO("sha1");

lib/crypto/Kconfig

@@ -146,6 +146,7 @@ config CRYPTO_LIB_SHA1
 config CRYPTO_LIB_SHA1_ARCH
 	bool
 	depends on CRYPTO_LIB_SHA1 && !UML
+	default y if ARM
 
 config CRYPTO_LIB_SHA256
 	tristate

lib/crypto/Makefile

@@ -71,6 +71,11 @@ obj-$(CONFIG_CRYPTO_LIB_SHA1) += libsha1.o
 libsha1-y := sha1.o
 ifeq ($(CONFIG_CRYPTO_LIB_SHA1_ARCH),y)
 CFLAGS_sha1.o += -I$(src)/$(SRCARCH)
+ifeq ($(CONFIG_ARM),y)
+libsha1-y += arm/sha1-armv4-large.o
+libsha1-$(CONFIG_KERNEL_MODE_NEON) += arm/sha1-armv7-neon.o \
+				      arm/sha1-ce-core.o
+endif
 endif # CONFIG_CRYPTO_LIB_SHA1_ARCH
 
 ################################################################################

lib/crypto/arm/sha1-armv7-neon.S

@@ -282,18 +282,17 @@
 
 
 /*
- * Transform nblks*64 bytes (nblks*16 32-bit words) at DATA.
+ * Transform nblocks*64 bytes (nblocks*16 32-bit words) at DATA.
  *
- * unsigned int
+ * void sha1_transform_neon(struct sha1_block_state *state,
- * sha1_transform_neon (void *ctx, const unsigned char *data,
+ *			    const u8 *data, size_t nblocks);
- *                      unsigned int nblks)
  */
 .align 3
 ENTRY(sha1_transform_neon)
   /* input:
-   *	r0: ctx, CTX
+   *	r0: state
-   *	r1: data (64*nblks bytes)
+   *	r1: data (64*nblocks bytes)
-   *	r2: nblks
+   *	r2: nblocks
    */
 
   cmp RNBLKS, #0;

lib/crypto/arm/sha1-ce-core.S

@@ -59,8 +59,8 @@
 	.word		0xca62c1d6, 0xca62c1d6, 0xca62c1d6, 0xca62c1d6
 
 	/*
-	 * void sha1_ce_transform(struct sha1_state *sst, u8 const *src,
+	 * void sha1_ce_transform(struct sha1_block_state *state,
-	 *			  int blocks);
+	 *			  const u8 *data, size_t nblocks);
 	 */
 ENTRY(sha1_ce_transform)
 	/* load round constants */

lib/crypto/arm/sha1.h

@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * SHA-1 optimized for ARM
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <asm/neon.h>
+#include <asm/simd.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce);
+
+asmlinkage void sha1_block_data_order(struct sha1_block_state *state,
+				      const u8 *data, size_t nblocks);
+asmlinkage void sha1_transform_neon(struct sha1_block_state *state,
+				    const u8 *data, size_t nblocks);
+asmlinkage void sha1_ce_transform(struct sha1_block_state *state,
+				  const u8 *data, size_t nblocks);
+
+static void sha1_blocks(struct sha1_block_state *state,
+			const u8 *data, size_t nblocks)
+{
+	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
+	    static_branch_likely(&have_neon) && likely(may_use_simd())) {
+		kernel_neon_begin();
+		if (static_branch_likely(&have_ce))
+			sha1_ce_transform(state, data, nblocks);
+		else
+			sha1_transform_neon(state, data, nblocks);
+		kernel_neon_end();
+	} else {
+		sha1_block_data_order(state, data, nblocks);
+	}
+}
+
+#ifdef CONFIG_KERNEL_MODE_NEON
+#define sha1_mod_init_arch sha1_mod_init_arch
+static inline void sha1_mod_init_arch(void)
+{
+	if (elf_hwcap & HWCAP_NEON) {
+		static_branch_enable(&have_neon);
+		if (elf_hwcap2 & HWCAP2_SHA1)
+			static_branch_enable(&have_ce);
+	}
+}
+#endif /* CONFIG_KERNEL_MODE_NEON */