1 files changed, 91 insertions, 0 deletions
diff --git a/lib/crypto/arm64/sha256.h b/lib/crypto/arm64/sha256.h
new file mode 100644
index 000000000000..568dff0f276a
--- /dev/null
+++ b/lib/crypto/arm64/sha256.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * SHA-256 optimized for ARM64
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <asm/simd.h>
+#include <linux/cpufeature.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce);
+
+asmlinkage void sha256_block_data_order(struct sha256_block_state *state,
+					const u8 *data, size_t nblocks);
+asmlinkage void sha256_block_neon(struct sha256_block_state *state,
+				  const u8 *data, size_t nblocks);
+asmlinkage size_t __sha256_ce_transform(struct sha256_block_state *state,
+					const u8 *data, size_t nblocks);
+
+static void sha256_blocks(struct sha256_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())) {
+		if (static_branch_likely(&have_ce)) {
+			do {
+				size_t rem;
+
+				scoped_ksimd()
+					rem = __sha256_ce_transform(state, data,
+								    nblocks);
+
+				data += (nblocks - rem) * SHA256_BLOCK_SIZE;
+				nblocks = rem;
+			} while (nblocks);
+		} else {
+			scoped_ksimd()
+				sha256_block_neon(state, data, nblocks);
+		}
+	} else {
+		sha256_block_data_order(state, data, nblocks);
+	}
+}
+
+static_assert(offsetof(struct __sha256_ctx, state) == 0);
+static_assert(offsetof(struct __sha256_ctx, bytecount) == 32);
+static_assert(offsetof(struct __sha256_ctx, buf) == 40);
+asmlinkage void sha256_ce_finup2x(const struct __sha256_ctx *ctx,
+				  const u8 *data1, const u8 *data2, int len,
+				  u8 out1[SHA256_DIGEST_SIZE],
+				  u8 out2[SHA256_DIGEST_SIZE]);
+
+#define sha256_finup_2x_arch sha256_finup_2x_arch
+static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx,
+				 const u8 *data1, const u8 *data2, size_t len,
+				 u8 out1[SHA256_DIGEST_SIZE],
+				 u8 out2[SHA256_DIGEST_SIZE])
+{
+	/*
+	 * The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX.
+	 * Further limit len to 65536 to avoid spending too long with preemption
+	 * disabled.  (Of course, in practice len is nearly always 4096 anyway.)
+	 */
+	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
+	    static_branch_likely(&have_ce) && len >= SHA256_BLOCK_SIZE &&
+	    len <= 65536 && likely(may_use_simd())) {
+		scoped_ksimd()
+			sha256_ce_finup2x(ctx, data1, data2, len, out1, out2);
+		kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE);
+		kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE);
+		return true;
+	}
+	return false;
+}
+
+static bool sha256_finup_2x_is_optimized_arch(void)
+{
+	return static_key_enabled(&have_ce);
+}
+
+#ifdef CONFIG_KERNEL_MODE_NEON
+#define sha256_mod_init_arch sha256_mod_init_arch
+static void sha256_mod_init_arch(void)
+{
+	if (cpu_have_named_feature(ASIMD)) {
+		static_branch_enable(&have_neon);
+		if (cpu_have_named_feature(SHA2))
+			static_branch_enable(&have_ce);
+	}
+}
+#endif /* CONFIG_KERNEL_MODE_NEON */