__p4d_populate
__p4d_populate(p4dp, __pa(pudp), p4dval);
__p4d_populate(p4dp, __pa_symbol(bm_pud),
__p4d_populate(p4dp, pud_phys, P4D_TYPE_TABLE);
__p4d_populate(p4dp, pud_phys, p4dval);
#define p4d_populate(MM, P4D, PUD) __p4d_populate(P4D, PUD)