1 files changed, 75 insertions, 0 deletions
diff --git a/arch/arm64/lib/crypto/sha256.c b/arch/arm64/lib/crypto/sha256.c
new file mode 100644
index 000000000000..bcf7a3adc0c4
--- /dev/null
+++ b/arch/arm64/lib/crypto/sha256.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * SHA-256 optimized for ARM64
+ *
+ * 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_neon(u32 state[SHA256_STATE_WORDS],
+				  const u8 *data, size_t nblocks);
+asmlinkage size_t __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)) {
+		if (static_branch_likely(&have_ce)) {
+			do {
+				size_t rem;
+
+				kernel_neon_begin();
+				rem = __sha256_ce_transform(state,
+							    data, nblocks);
+				kernel_neon_end();
+				data += (nblocks - rem) * SHA256_BLOCK_SIZE;
+				nblocks = rem;
+			} while (nblocks);
+		} else {
+			kernel_neon_begin();
+			sha256_block_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 ARM64 scalar implementation. */
+	return true;
+}
+EXPORT_SYMBOL_GPL(sha256_is_arch_optimized);
+
+static int __init sha256_arm64_mod_init(void)
+{
+	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
+	    cpu_have_named_feature(ASIMD)) {
+		static_branch_enable(&have_neon);
+		if (cpu_have_named_feature(SHA2))
+			static_branch_enable(&have_ce);
+	}
+	return 0;
+}
+subsys_initcall(sha256_arm64_mod_init);
+
+static void __exit sha256_arm64_mod_exit(void)
+{
+}
+module_exit(sha256_arm64_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SHA-256 optimized for ARM64");