[PATCH 14/16 v4] pramfs: write protection

[Marco Stornelli <marco.stornelli@gmail.com>]

From: Marco Stornelli <marco.stornelli@gmail.com>

Memory write protection.

Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
---
diff -Nurp linux-2.6.36-orig/fs/pramfs/wprotect.c linux-2.6.36/fs/pramfs/wprotect.c
--- linux-2.6.36-orig/fs/pramfs/wprotect.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/wprotect.c	2010-10-30 11:59:54.000000000 +0200
@@ -0,0 +1,41 @@
+/*
+ * FILE NAME fs/pramfs/wprotect.c
+ *
+ * BRIEF DESCRIPTION
+ *
+ * Write protection for the filesystem pages.
+ *
+ * Copyright 2009-2010 Marco Stornelli <marco.stornelli@gmail.com>
+ * Copyright 2003 Sony Corporation
+ * Copyright 2003 Matsushita Electric Industrial Co., Ltd.
+ * 2003-2004 (c) MontaVista Software, Inc. , Steve Longerbeam
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+#include "pram.h"
+
+void pram_writeable(void *vaddr, unsigned long size, int rw)
+{
+	int ret = 0;
+	unsigned long nrpages = size >> PAGE_SHIFT;
+	unsigned long addr = (unsigned long)vaddr;
+
+	/* Page aligned */
+	addr &= PAGE_MASK;
+
+	if (size & (PAGE_SIZE - 1))
+		nrpages++;
+
+	if (rw)
+		ret = set_memory_rw(addr, nrpages);
+	else
+		ret = set_memory_ro(addr, nrpages);
+
+	BUG_ON(ret);
+}