PG_FOE
npte |= PG_FOR | PG_FOW | PG_FOE;
pmap_changebit(pg, PG_FOR | PG_FOW | PG_FOE, ~0UL, &tlbctx);
kp[prot] |= PG_FOE;
up[prot] |= PG_FOE;
faultoff |= PG_FOE;
#define PG_PROT (ALPHA_PTE_PROT | PG_EXEC | PG_FOE)