x86: move devmem_is_allowed() to common mm/init.c
Impact: cleanup
The function is identical on 32-bit and 64-bit configurations so move
it to the common mm/init.c file.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1236160001.29024.29.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index ce6a722..f89df52 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -1,9 +1,33 @@
+#include <linux/ioport.h>
#include <linux/swap.h>
+
#include <asm/cacheflush.h>
#include <asm/page.h>
+#include <asm/page_types.h>
#include <asm/sections.h>
#include <asm/system.h>
+/*
+ * 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 (iomem_is_exclusive(pagenr << PAGE_SHIFT))
+ return 0;
+ if (!page_is_ram(pagenr))
+ return 1;
+ return 0;
+}
+
void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
unsigned long addr = begin;