1 files changed, 95 insertions, 0 deletions
diff --git a/lib/crypto/x86/sha256.h b/lib/crypto/x86/sha256.h
new file mode 100644
index 000000000000..38e33b22a092
--- /dev/null
+++ b/lib/crypto/x86/sha256.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * SHA-256 optimized for x86_64
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <asm/fpu/api.h>
+#include <linux/static_call.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha_ni);
+
+DEFINE_STATIC_CALL(sha256_blocks_x86, sha256_blocks_generic);
+
+#define DEFINE_X86_SHA256_FN(c_fn, asm_fn)                                 \
+	asmlinkage void asm_fn(struct sha256_block_state *state,           \
+			       const u8 *data, size_t nblocks);            \
+	static void c_fn(struct sha256_block_state *state, const u8 *data, \
+			 size_t nblocks)                                   \
+	{                                                                  \
+		if (likely(irq_fpu_usable())) {                            \
+			kernel_fpu_begin();                                \
+			asm_fn(state, data, nblocks);                      \
+			kernel_fpu_end();                                  \
+		} else {                                                   \
+			sha256_blocks_generic(state, data, nblocks);       \
+		}                                                          \
+	}
+
+DEFINE_X86_SHA256_FN(sha256_blocks_ssse3, sha256_transform_ssse3);
+DEFINE_X86_SHA256_FN(sha256_blocks_avx, sha256_transform_avx);
+DEFINE_X86_SHA256_FN(sha256_blocks_avx2, sha256_transform_rorx);
+DEFINE_X86_SHA256_FN(sha256_blocks_ni, sha256_ni_transform);
+
+static void sha256_blocks(struct sha256_block_state *state,
+			  const u8 *data, size_t nblocks)
+{
+	static_call(sha256_blocks_x86)(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_ni_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 (static_branch_likely(&have_sha_ni) && len >= SHA256_BLOCK_SIZE &&
+	    len <= 65536 && likely(irq_fpu_usable())) {
+		kernel_fpu_begin();
+		sha256_ni_finup2x(ctx, data1, data2, len, out1, out2);
+		kernel_fpu_end();
+		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_sha_ni);
+}
+
+#define sha256_mod_init_arch sha256_mod_init_arch
+static void sha256_mod_init_arch(void)
+{
+	if (boot_cpu_has(X86_FEATURE_SHA_NI)) {
+		static_call_update(sha256_blocks_x86, sha256_blocks_ni);
+		static_branch_enable(&have_sha_ni);
+	} else if (cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM,
+				     NULL) &&
+		   boot_cpu_has(X86_FEATURE_AVX)) {
+		if (boot_cpu_has(X86_FEATURE_AVX2) &&
+		    boot_cpu_has(X86_FEATURE_BMI2))
+			static_call_update(sha256_blocks_x86,
+					   sha256_blocks_avx2);
+		else
+			static_call_update(sha256_blocks_x86,
+					   sha256_blocks_avx);
+	} else if (boot_cpu_has(X86_FEATURE_SSSE3)) {
+		static_call_update(sha256_blocks_x86, sha256_blocks_ssse3);
+	}
+}