[PATCH] Enable mprotect on huge pages

[karo-tx-linux.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 20117a4b8ab6613bc34387c605c67929f4672462..783098f6cf8e46ecb65527ad2f093878311a16ad 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -565,3 +565,32 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
        return i;
 }
+
+void hugetlb_change_protection(struct vm_area_struct *vma,
+               unsigned long address, unsigned long end, pgprot_t newprot)
+{
+       struct mm_struct *mm = vma->vm_mm;
+       unsigned long start = address;
+       pte_t *ptep;
+       pte_t pte;
+
+       BUG_ON(address >= end);
+       flush_cache_range(vma, address, end);
+
+       spin_lock(&mm->page_table_lock);
+       for (; address < end; address += HPAGE_SIZE) {
+               ptep = huge_pte_offset(mm, address);
+               if (!ptep)
+                       continue;
+               if (!pte_none(*ptep)) {
+                       pte = huge_ptep_get_and_clear(mm, address, ptep);
+                       pte = pte_mkhuge(pte_modify(pte, newprot));
+                       set_huge_pte_at(mm, address, ptep, pte);
+                       lazy_mmu_prot_update(pte);
+               }
+       }
+       spin_unlock(&mm->page_table_lock);
+
+       flush_tlb_range(vma, start, end);
+}
+