diff -drupN a/security/fivm/fivm_crypto.c b/security/fivm/fivm_crypto.c
--- a/security/fivm/fivm_crypto.c	1970-01-01 03:00:00.000000000 +0300
+++ b/security/fivm/fivm_crypto.c	2022-06-12 05:28:14.000000000 +0300
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2014 Allwinner Ltd.
+ *
+ * Author:
+ *	Ryan Chen <ryanchen@allwinnertech.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: fivm_crypto.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/crypto.h>
+#include <linux/scatterlist.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include "fivm.h"
+
+static char *fivm_hash = "sha256";
+static int init_desc(struct hash_desc *desc)
+{
+	int rc;
+
+	desc->tfm = crypto_alloc_hash(fivm_hash, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(desc->tfm)) {
+		pr_info("FIVM: failed to load %s transform: %ld\n",
+			fivm_hash, PTR_ERR(desc->tfm));
+		rc = PTR_ERR(desc->tfm);
+		return rc;
+	}
+	desc->flags = 0;
+	rc = crypto_hash_init(desc);
+	if (rc)
+		crypto_free_hash(desc->tfm);
+	return rc;
+}
+
+int fivm_calc_hash(struct file *file, char *digest)
+{
+	struct hash_desc desc;
+	struct scatterlist sg[1];
+	loff_t i_size, offset = 0;
+	char *rbuf;
+	int rc;
+
+	rc = init_desc(&desc);
+	if (rc != 0)
+		return rc;
+
+	rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!rbuf) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	i_size = i_size_read(file->f_path.dentry->d_inode);
+	while (offset < i_size) {
+		int rbuf_len;
+		rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
+		if (rbuf_len < 0) {
+			rc = rbuf_len;
+			break;
+		}
+		if (rbuf_len == 0)
+			break;
+		offset += rbuf_len;
+		sg_init_one(sg, rbuf, rbuf_len);
+
+		rc = crypto_hash_update(&desc, sg, rbuf_len);
+		if (rc)
+			break;
+	}
+	kfree(rbuf);
+	if (!rc)
+		rc = crypto_hash_final(&desc, digest);
+out:
+	crypto_free_hash(desc.tfm);
+	return rc;
+}