effective_prot
effective_prot(st, 4, pte_val(pte));
effective_prot(st, 3, pmd_val(pmd));
effective_prot(st, 2, pud_val(pud));
effective_prot(st, 1, p4d_val(p4d));
effective_prot(st, 0, pgd_val(pgd));
pgprotval_t effective_prot;
eff = st->effective_prot;
st->effective_prot = new_eff;
st->effective_prot = new_eff;