PHYS_MASK_SHIFT
#define PHYS_MASK ((1ULL << PHYS_MASK_SHIFT) - 1)
#define PHYS_MASK ((UL(1) << PHYS_MASK_SHIFT) - 1)
#define MAX_PHYSMEM_BITS PHYS_MASK_SHIFT
memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX);