x86: PAT avoid aliasing in /dev/mem read/write

Add xlate and unxlate around /dev/mem read/write. This sets up the mapping
that can be used for /dev/mem read and write without aliasing worries.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/asm-x86/io.h

@@ -1,3 +1,6 @@
+#ifndef _ASM_X86_IO_H
+#define _ASM_X86_IO_H
+
 #define ARCH_HAS_IOREMAP_WC
 
 #ifdef CONFIG_X86_32
@@ -5,7 +8,12 @@
 #else
 # include "io_64.h"
 #endif
+
+extern void *xlate_dev_mem_ptr(unsigned long phys);
+extern void unxlate_dev_mem_ptr(unsigned long phys, void *addr);
+
 extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 				unsigned long prot_val);
 extern void __iomem *ioremap_wc(unsigned long offset, unsigned long size);
 
+#endif /* _ASM_X86_IO_H */

include/asm-x86/io_32.h

@@ -48,12 +48,6 @@
 
 #include <linux/vmalloc.h>
 
-/*
- * Convert a physical pointer to a virtual kernel pointer for /dev/mem
- * access
- */
-#define xlate_dev_mem_ptr(p)	__va(p)
-
 /*
  * Convert a virtual cached pointer to an uncached pointer
  */

include/asm-x86/io_64.h

@@ -307,12 +307,6 @@ void memset_io(volatile void __iomem *a, int b, size_t c);
 extern int iommu_bio_merge;
 #define BIO_VMERGE_BOUNDARY iommu_bio_merge
 
-/*
- * Convert a physical pointer to a virtual kernel pointer for /dev/mem
- * access
- */
-#define xlate_dev_mem_ptr(p)	__va(p)
-
 /*
  * Convert a virtual cached pointer to an uncached pointer
  */