PLD_SHIFT
#define PMD_SHIFT (PLD_SHIFT + BITS_PER_PTE)
#define PGDIR_SHIFT (PLD_SHIFT + BITS_PER_PTE + BITS_PER_PMD)
#if (KERNEL_INITIAL_ORDER) >= (PLD_SHIFT + BITS_PER_PTE)
# define PT_INITIAL (1 << (KERNEL_INITIAL_ORDER - PLD_SHIFT - BITS_PER_PTE))