pte_clear(mm, addr, ptep);
unsigned long old = pte_update(ptep, ~0UL); if (old & _PAGE_HASHPTE) hpte_update(mm, addr & HPAGE_MASK, ptep, old, 1);
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,		     pte_t *ptep, pte_t pte){	int i;	if (pte_present(*ptep)) {		pte_clear(mm, addr, ptep);		flush_tlb_pending();	}	for (i = 0; i < HUGEPTE_BATCH_SIZE; i++) {		*ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);		ptep++;	}}