PG_REF
#define PG_SPECIAL (PG_VALID|PG_WRITE|PG_SYSTEM|PG_NC|PG_REF|PG_MOD)
#define PG_MODREF (PG_REF|PG_MOD)
if (pte & PG_REF)
if (clear_bits & ~(PG_WRITE | PG_NC | PG_REF | PG_MOD))
new_pte |= PG_REF;
#define PV_REF (PG_REF >> PV_SHIFT)
#define PG_SPECIAL (PG_VALID|PG_WRITE|PG_SYSTEM|PG_NC|PG_REF|PG_MOD)
#define PG_MODREF (PG_REF|PG_MOD)
if (pte & PG_REF)
if (clear_bits & ~(PG_WRITE | PG_NC | PG_REF | PG_MOD))
new_pte |= PG_REF;