__PHYSICAL_MASK_SHIFT is used to define the mask that helps to extract physical address from a page table entry.
Although, real physical address space available may differ between machines, it's safe to use 52 as __PHYSICAL_MASK_SHIFT. Unused bits above log2(MAXPHYADDR) up to bit 51 are reserved and must be 0. Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> --- arch/x86/include/asm/page_64_types.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h index e1407312c412..f68e6526891d 100644 --- a/arch/x86/include/asm/page_64_types.h +++ b/arch/x86/include/asm/page_64_types.h @@ -52,11 +52,12 @@ #define __START_KERNEL_map _AC(0xffffffff80000000, UL) /* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */ -#ifdef CONFIG_X86_5LEVEL + #define __PHYSICAL_MASK_SHIFT 52 + +#ifdef CONFIG_X86_5LEVEL #define __VIRTUAL_MASK_SHIFT 56 #else -#define __PHYSICAL_MASK_SHIFT 46 #define __VIRTUAL_MASK_SHIFT 47 #endif -- 2.15.1