X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=mm%2Fmprotect.c;h=4de546899dc140d139f218fc53ff0c358c6c5a42;hb=1a823ac9ff09cbdf39201df37b7ede1f9395de83;hp=638edabaff7118206b379c0436ffd6aa3e2fda40;hpb=075395d228641646159dae3dd170fa3fc6ff477a;p=linux-2.6-omap-h63xx.git

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 638edabaff7..4de546899dc 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -27,12 +27,14 @@
 #include <asm/tlbflush.h>
 
 static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
-		unsigned long addr, unsigned long end, pgprot_t newprot)
+		unsigned long addr, unsigned long end, pgprot_t newprot,
+		int dirty_accountable)
 {
 	pte_t *pte, oldpte;
 	spinlock_t *ptl;
 
 	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+	arch_enter_lazy_mmu_mode();
 	do {
 		oldpte = *pte;
 		if (pte_present(oldpte)) {
@@ -42,9 +44,15 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
 			 * bits by wiping the pte and then setting the new pte
 			 * into place.
 			 */
-			ptent = pte_modify(ptep_get_and_clear(mm, addr, pte), newprot);
+			ptent = ptep_get_and_clear(mm, addr, pte);
+			ptent = pte_modify(ptent, newprot);
+			/*
+			 * Avoid taking write faults for pages we know to be
+			 * dirty.
+			 */
+			if (dirty_accountable && pte_dirty(ptent))
+				ptent = pte_mkwrite(ptent);
 			set_pte_at(mm, addr, pte, ptent);
-			lazy_mmu_prot_update(ptent);
 #ifdef CONFIG_MIGRATION
 		} else if (!pte_file(oldpte)) {
 			swp_entry_t entry = pte_to_swp_entry(oldpte);
@@ -62,11 +70,13 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
 		}
 
 	} while (pte++, addr += PAGE_SIZE, addr != end);
+	arch_leave_lazy_mmu_mode();
 	pte_unmap_unlock(pte - 1, ptl);
 }
 
 static inline void change_pmd_range(struct mm_struct *mm, pud_t *pud,
-		unsigned long addr, unsigned long end, pgprot_t newprot)
+		unsigned long addr, unsigned long end, pgprot_t newprot,
+		int dirty_accountable)
 {
 	pmd_t *pmd;
 	unsigned long next;
@@ -76,12 +86,13 @@ static inline void change_pmd_range(struct mm_struct *mm, pud_t *pud,
 		next = pmd_addr_end(addr, end);
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
-		change_pte_range(mm, pmd, addr, next, newprot);
+		change_pte_range(mm, pmd, addr, next, newprot, dirty_accountable);
 	} while (pmd++, addr = next, addr != end);
 }
 
 static inline void change_pud_range(struct mm_struct *mm, pgd_t *pgd,
-		unsigned long addr, unsigned long end, pgprot_t newprot)
+		unsigned long addr, unsigned long end, pgprot_t newprot,
+		int dirty_accountable)
 {
 	pud_t *pud;
 	unsigned long next;
@@ -91,12 +102,13 @@ static inline void change_pud_range(struct mm_struct *mm, pgd_t *pgd,
 		next = pud_addr_end(addr, end);
 		if (pud_none_or_clear_bad(pud))
 			continue;
-		change_pmd_range(mm, pud, addr, next, newprot);
+		change_pmd_range(mm, pud, addr, next, newprot, dirty_accountable);
 	} while (pud++, addr = next, addr != end);
 }
 
 static void change_protection(struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end, pgprot_t newprot)
+		unsigned long addr, unsigned long end, pgprot_t newprot,
+		int dirty_accountable)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	pgd_t *pgd;
@@ -110,12 +122,12 @@ static void change_protection(struct vm_area_struct *vma,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none_or_clear_bad(pgd))
 			continue;
-		change_pud_range(mm, pgd, addr, next, newprot);
+		change_pud_range(mm, pgd, addr, next, newprot, dirty_accountable);
 	} while (pgd++, addr = next, addr != end);
 	flush_tlb_range(vma, start, end);
 }
 
-static int
+int
 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	unsigned long start, unsigned long end, unsigned long newflags)
 {
@@ -123,10 +135,9 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	unsigned long oldflags = vma->vm_flags;
 	long nrpages = (end - start) >> PAGE_SHIFT;
 	unsigned long charged = 0;
-	unsigned int mask;
-	pgprot_t newprot;
 	pgoff_t pgoff;
 	int error;
+	int dirty_accountable = 0;
 
 	if (newflags == oldflags) {
 		*pprev = vma;
@@ -176,24 +187,21 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	}
 
 success:
-	/* Don't make the VMA automatically writable if it's shared, but the
-	 * backer wishes to know when pages are first written to */
-	mask = VM_READ|VM_WRITE|VM_EXEC|VM_SHARED;
-	if (vma->vm_ops && vma->vm_ops->page_mkwrite)
-		mask &= ~VM_SHARED;
-
-	newprot = protection_map[newflags & mask];
-
 	/*
 	 * vm_flags and vm_page_prot are protected by the mmap_sem
 	 * held in write mode.
 	 */
 	vma->vm_flags = newflags;
-	vma->vm_page_prot = newprot;
+	vma->vm_page_prot = vm_get_page_prot(newflags);
+	if (vma_wants_writenotify(vma)) {
+		vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
+		dirty_accountable = 1;
+	}
+
 	if (is_vm_hugetlb_page(vma))
-		hugetlb_change_protection(vma, start, end, newprot);
+		hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
 	else
-		change_protection(vma, start, end, newprot);
+		change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable);
 	vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
 	vm_stat_account(mm, newflags, vma->vm_file, nrpages);
 	return 0;