diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 9ec62da..39852d5 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -227,6 +227,25 @@
 	return 0;
 }
 
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ *
+ * On x86, access has to be given to the first megabyte of ram because that area
+ * contains bios code and data regions used by X and dosemu and similar apps.
+ * Access has to be given to non-kernel-ram areas as well, these contain the PCI
+ * mmio resources as well as potential bios/acpi data regions.
+ */
+int devmem_is_allowed(unsigned long pagenr)
+{
+	if (pagenr <= 256)
+		return 1;
+	if (!page_is_ram(pagenr))
+		return 1;
+	return 0;
+}
+
 #ifdef CONFIG_HIGHMEM
 pte_t *kmap_pte;
 pgprot_t kmap_prot;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 1ff7906..49c274e 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -664,6 +664,26 @@
 
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ *
+ * On x86, access has to be given to the first megabyte of ram because that area
+ * contains bios code and data regions used by X and dosemu and similar apps.
+ * Access has to be given to non-kernel-ram areas as well, these contain the PCI
+ * mmio resources as well as potential bios/acpi data regions.
+ */
+int devmem_is_allowed(unsigned long pagenr)
+{
+	if (pagenr <= 256)
+		return 1;
+	if (!page_is_ram(pagenr))
+		return 1;
+	return 0;
+}
+
+
 static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel,
 			 kcore_modules, kcore_vsyscall;