--- zzzz-none-000/linux-2.6.39.4/drivers/char/mem.c	2011-08-03 19:43:28.000000000 +0000
+++ puma6-atom-6490-729/linux-2.6.39.4/drivers/char/mem.c	2021-11-10 13:38:14.000000000 +0000
@@ -8,6 +8,13 @@
  *  Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
  */
 
+/******************************************************************
+ 
+ Includes Intel Corporation's changes/modifications dated: 01/2013.
+ Changed/modified portions - Copyright(c) 2013, Intel Corporation. 
+
+******************************************************************/
+
 #include <linux/mm.h>
 #include <linux/miscdevice.h>
 #include <linux/slab.h>
@@ -34,6 +41,26 @@
 # include <linux/efi.h>
 #endif
 
+#ifdef CONFIG_ARCH_GEN3
+int range_is_sys_ram(unsigned long pfn, unsigned long size)
+{
+        u64 from = ((u64)pfn) << PAGE_SHIFT;
+        u64 to = from + size;
+        u64 cursor = from;
+
+        while (cursor < to) {
+                if (page_is_ram(pfn)) {
+                        printk(KERN_INFO "system ram! pfn 0x%x.\n", (unsigned int)pfn);
+                        return 1;
+                }
+                cursor += PAGE_SIZE;
+                pfn++;
+        }
+        return 0;
+}
+EXPORT_SYMBOL(range_is_sys_ram);
+#endif
+
 static inline unsigned long size_inside_page(unsigned long start,
 					     unsigned long size)
 {