1 files changed, 64 insertions, 0 deletions
diff --git a/arch/arm/lib/crypto/sha256.c b/arch/arm/lib/crypto/sha256.c
new file mode 100644
index 000000000000..109192e54b0f
--- /dev/null
+++ b/arch/arm/lib/crypto/sha256.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * SHA-256 optimized for ARM
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <asm/neon.h>
+#include <crypto/internal/sha2.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+asmlinkage void sha256_blocks_arch(u32 state[SHA256_STATE_WORDS],
+				   const u8 *data, size_t nblocks);
+EXPORT_SYMBOL_GPL(sha256_blocks_arch);
+asmlinkage void sha256_block_data_order_neon(u32 state[SHA256_STATE_WORDS],
+					     const u8 *data, size_t nblocks);
+asmlinkage void sha256_ce_transform(u32 state[SHA256_STATE_WORDS],
+				    const u8 *data, size_t nblocks);
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce);
+
+void sha256_blocks_simd(u32 state[SHA256_STATE_WORDS],
+			const u8 *data, size_t nblocks)
+{
+	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
+	    static_branch_likely(&have_neon)) {
+		kernel_neon_begin();
+		if (static_branch_likely(&have_ce))
+			sha256_ce_transform(state, data, nblocks);
+		else
+			sha256_block_data_order_neon(state, data, nblocks);
+		kernel_neon_end();
+	} else {
+		sha256_blocks_arch(state, data, nblocks);
+	}
+}
+EXPORT_SYMBOL_GPL(sha256_blocks_simd);
+
+bool sha256_is_arch_optimized(void)
+{
+	/* We always can use at least the ARM scalar implementation. */
+	return true;
+}
+EXPORT_SYMBOL_GPL(sha256_is_arch_optimized);
+
+static int __init sha256_arm_mod_init(void)
+{
+	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON)) {
+		static_branch_enable(&have_neon);
+		if (elf_hwcap2 & HWCAP2_SHA2)
+			static_branch_enable(&have_ce);
+	}
+	return 0;
+}
+subsys_initcall(sha256_arm_mod_init);
+
+static void __exit sha256_arm_mod_exit(void)
+{
+}
+module_exit(sha256_arm_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SHA-256 optimized for ARM");