PUD_SIZE 52 arch/x86/include/asm/pgtable_64_types.h #define PUD_MASK (~(PUD_SIZE - 1)) PUD_SIZE 18 include/asm-generic/pgtable-nopud.h #define PUD_MASK (~(PUD_SIZE-1)) PUD_SIZE 283 include/asm-generic/pgtable.h ({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK; \