===== arch/ia64/mm/hugetlbpage.c 1.18 vs edited =====
--- 1.18/arch/ia64/mm/hugetlbpage.c	Thu Feb 26 12:18:51 2004
+++ edited/arch/ia64/mm/hugetlbpage.c	Fri Apr  2 11:41:06 2004
@@ -162,8 +162,10 @@
 			goto nomem;
 		src_pte = huge_pte_offset(src, addr);
 		entry = *src_pte;
-		ptepage = pte_page(entry);
-		get_page(ptepage);
+		if (!pte_none(entry)) {
+			ptepage = pte_page(entry);
+			get_page(ptepage);
+		}
 		set_pte(dst_pte, entry);
 		dst->rss += (HPAGE_SIZE / PAGE_SIZE);
 		addr += HPAGE_SIZE;
@@ -187,6 +189,12 @@
 	do {
 		pstart = start & HPAGE_MASK;
 		ptep = huge_pte_offset(mm, start);
+
+		if (!ptep || pte_none(*ptep)) {
+			hugetlb_fault(mm, vma, 0, start);
+			ptep = huge_pte_offset(mm, start);
+		}
+
 		pte = *ptep;
 
 back1:
@@ -228,6 +236,12 @@
 	pte_t *ptep;
 
 	ptep = huge_pte_offset(mm, addr);
+
+	if (!ptep || pte_none(*ptep)) {
+		hugetlb_fault(mm, vma, 0, addr);
+		ptep = huge_pte_offset(mm, addr);
+	}
+
 	page = pte_page(*ptep);
 	page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 	get_page(page);
@@ -238,7 +252,8 @@
 	return 0;
 }
 struct page *
-follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write)
+follow_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
+		unsigned long address, pmd_t *pmd, int write)
 {
 	return NULL;
 }
@@ -349,6 +364,8 @@
 
 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 {
+	return 0;
+#if 0
 	struct mm_struct *mm = current->mm;
 	unsigned long addr;
 	int ret = 0;
@@ -397,6 +414,7 @@
 out:
 	spin_unlock(&mm->page_table_lock);
 	return ret;
+#endif
 }
 
 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
@@ -590,6 +608,48 @@
 	if (size > (htlbpagemem << HPAGE_SHIFT))
 		return 0;
 	return 1;
+}
+
+int arch_hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+		       int write_access, unsigned long address)
+{
+	struct file *file = vma->vm_file;
+	struct address_space *mapping = file->f_dentry->d_inode->i_mapping;
+	struct page *page;
+	unsigned long idx;
+	pte_t *pte;
+	int ret = VM_FAULT_MINOR;
+
+	BUG_ON(vma->vm_start & ~HPAGE_MASK);
+	BUG_ON(vma->vm_end & ~HPAGE_MASK);
+
+	spin_lock(&mm->page_table_lock);
+
+	idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
+		+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
+	page = find_get_page(mapping, idx);
+
+	if (!page) {
+		page = alloc_hugetlb_page();
+		if (!page) {
+			ret = VM_FAULT_SIGBUS;
+			goto out;
+		}
+		ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
+		unlock_page(page);
+		if (ret) {
+			free_huge_page(page);
+			ret = VM_FAULT_SIGBUS;
+			goto out;
+		}
+	}
+	pte = huge_pte_alloc(mm, address);
+	set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
+	flush_tlb_range(vma, address, address + HPAGE_SIZE);
+	update_mmu_cache(vma, address, *pte);
+ out:
+	spin_unlock(&mm->page_table_lock);
+	return ret;
 }
 
 static struct page *hugetlb_nopage(struct vm_area_struct * area, unsigned long address, int *unused)