1 files changed, 56 insertions, 0 deletions
diff --git a/arch/s390/lib/crypto/chacha-glue.c b/arch/s390/lib/crypto/chacha-glue.c
new file mode 100644
index 000000000000..f95ba3483bbc
--- /dev/null
+++ b/arch/s390/lib/crypto/chacha-glue.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ChaCha stream cipher (s390 optimized)
+ *
+ * Copyright IBM Corp. 2021
+ */
+
+#define KMSG_COMPONENT "chacha_s390"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <crypto/chacha.h>
+#include <linux/cpufeature.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <asm/fpu.h>
+#include "chacha-s390.h"
+
+void hchacha_block_arch(const struct chacha_state *state,
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
+{
+	/* TODO: implement hchacha_block_arch() in assembly */
+	hchacha_block_generic(state, out, nrounds);
+}
+EXPORT_SYMBOL(hchacha_block_arch);
+
+void chacha_crypt_arch(struct chacha_state *state, u8 *dst, const u8 *src,
+		       unsigned int bytes, int nrounds)
+{
+	/* s390 chacha20 implementation has 20 rounds hard-coded,
+	 * it cannot handle a block of data or less, but otherwise
+	 * it can handle data of arbitrary size
+	 */
+	if (bytes <= CHACHA_BLOCK_SIZE || nrounds != 20 || !cpu_has_vx()) {
+		chacha_crypt_generic(state, dst, src, bytes, nrounds);
+	} else {
+		DECLARE_KERNEL_FPU_ONSTACK32(vxstate);
+
+		kernel_fpu_begin(&vxstate, KERNEL_VXR);
+		chacha20_vx(dst, src, bytes, &state->x[4], &state->x[12]);
+		kernel_fpu_end(&vxstate, KERNEL_VXR);
+
+		state->x[12] += round_up(bytes, CHACHA_BLOCK_SIZE) /
+				CHACHA_BLOCK_SIZE;
+	}
+}
+EXPORT_SYMBOL(chacha_crypt_arch);
+
+bool chacha_is_arch_optimized(void)
+{
+	return cpu_has_vx();
+}
+EXPORT_SYMBOL(chacha_is_arch_optimized);
+
+MODULE_DESCRIPTION("ChaCha stream cipher (s390 optimized)");
+MODULE_LICENSE("GPL v2");