PUD_PAGE_MASK      27 arch/x86/include/asm/page_types.h #define PHYSICAL_PUD_PAGE_MASK	(((signed long)PUD_PAGE_MASK) & __PHYSICAL_MASK)
PUD_PAGE_MASK     687 arch/x86/mm/pageattr.c 		offset = virt_addr & ~PUD_PAGE_MASK;