1 files changed, 47 insertions, 0 deletions
diff --git a/arch/s390/lib/crypto/sha256.c b/arch/s390/lib/crypto/sha256.c
new file mode 100644
index 000000000000..7dfe120fafab
--- /dev/null
+++ b/arch/s390/lib/crypto/sha256.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * SHA-256 optimized using the CP Assist for Cryptographic Functions (CPACF)
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <asm/cpacf.h>
+#include <crypto/internal/sha2.h>
+#include <linux/cpufeature.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_sha256);
+
+void sha256_blocks_arch(u32 state[SHA256_STATE_WORDS],
+			const u8 *data, size_t nblocks)
+{
+	if (static_branch_likely(&have_cpacf_sha256))
+		cpacf_kimd(CPACF_KIMD_SHA_256, state, data,
+			   nblocks * SHA256_BLOCK_SIZE);
+	else
+		sha256_blocks_generic(state, data, nblocks);
+}
+EXPORT_SYMBOL_GPL(sha256_blocks_arch);
+
+bool sha256_is_arch_optimized(void)
+{
+	return static_key_enabled(&have_cpacf_sha256);
+}
+EXPORT_SYMBOL_GPL(sha256_is_arch_optimized);
+
+static int __init sha256_s390_mod_init(void)
+{
+	if (cpu_have_feature(S390_CPU_FEATURE_MSA) &&
+	    cpacf_query_func(CPACF_KIMD, CPACF_KIMD_SHA_256))
+		static_branch_enable(&have_cpacf_sha256);
+	return 0;
+}
+subsys_initcall(sha256_s390_mod_init);
+
+static void __exit sha256_s390_mod_exit(void)
+{
+}
+module_exit(sha256_s390_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SHA-256 using the CP Assist for Cryptographic Functions (CPACF)");