Definition canonicalPMap fn n m : Maps.PMap.t (Z -> perm_kind -> option permission) :=
    let l := mkBlockList n in
    (fun _ _ => None, canonicalPTree (PList fn l m)).Definition setMaxPerm (m : mem) : mem.

Lemma setMaxPerm_Cur : forall m b ofs, permission_at (setMaxPerm m) b ofs Cur = permission_at m b ofs Cur.