Re: [PATCH net-next v7 25/28] crypto: port Poly1305 to Zinc

diff --git a/crypto/poly1305_zinc.c b/crypto/poly1305_zinc.c
new file mode 100644
index 000000000000..4794442edf26
--- /dev/null
+++ b/crypto/poly1305_zinc.c

@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/internal/hash.h>
+#include <zinc/poly1305.h>
+#include <linux/crypto.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/simd.h>
+
+struct poly1305_desc_ctx {
+	struct poly1305_ctx ctx;
+	u8 key[POLY1305_KEY_SIZE];
+	unsigned int rem_key_bytes;
+};
+
+static int crypto_poly1305_init(struct shash_desc *desc)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+	dctx->rem_key_bytes = POLY1305_KEY_SIZE;
+	return 0;
+}
+
+static int crypto_poly1305_update(struct shash_desc *desc, const u8 *src,
+				  unsigned int srclen)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+	simd_context_t simd_context;
+
+	if (unlikely(dctx->rem_key_bytes)) {
+		unsigned int key_bytes = min(srclen, dctx->rem_key_bytes);
+		memcpy(dctx->key + (POLY1305_KEY_SIZE - dctx->rem_key_bytes),
+		       src, key_bytes);
+		src += key_bytes;
+		srclen -= key_bytes;
+		dctx->rem_key_bytes -= key_bytes;
+		if (!dctx->rem_key_bytes) {
+			poly1305_init(&dctx->ctx, dctx->key);
+			memzero_explicit(dctx->key, sizeof(dctx->key));
+		}
+		if (!srclen)
+			return 0;
+	}
+
+	simd_get(&simd_context);
+	poly1305_update(&dctx->ctx, src, srclen, &simd_context);
+	simd_put(&simd_context);
+
+	return 0;
+}
+
+static int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+	simd_context_t simd_context;
+
+	simd_get(&simd_context);
+	poly1305_final(&dctx->ctx, dst, &simd_context);
+	simd_put(&simd_context);
+	return 0;
+}