__PHYSICAL_MASK_SHIFT 13 include/asm-x86/page.h #define __PHYSICAL_MASK ((phys_addr_t)(1ULL << __PHYSICAL_MASK_SHIFT) - 1) __PHYSICAL_MASK_SHIFT 231 include/asm-x86/pgtable_64.h #define PTE_FILE_MAX_BITS __PHYSICAL_MASK_SHIFT