1 files changed, 43 insertions, 7 deletions

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 192b3ba070755..f58ea503ad014 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -117,11 +117,14 @@ static pte_t get_clear_flush(struct mm_struct *mm,
 
 		/*
 		 * If HW_AFDBM is enabled, then the HW could turn on
-		 * the dirty bit for any page in the set, so check
-		 * them all.  All hugetlb entries are already young.
+		 * the dirty or accessed bit for any page in the set,
+		 * so check them all.
 		 */
 		if (pte_dirty(pte))
 			orig_pte = pte_mkdirty(orig_pte);
+
+		if (pte_young(pte))
+			orig_pte = pte_mkyoung(orig_pte);
 	}
 
 	if (valid) {
@@ -320,11 +323,40 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 	return get_clear_flush(mm, addr, ptep, pgsize, ncontig);
 }
 
+/*
+ * huge_ptep_set_access_flags will update access flags (dirty, accesssed)
+ * and write permission.
+ *
+ * For a contiguous huge pte range we need to check whether or not write
+ * permission has to change only on the first pte in the set. Then for
+ * all the contiguous ptes we need to check whether or not there is a
+ * discrepancy between dirty or young.
+ */
+static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig)
+{
+	int i;
+
+	if (pte_write(pte) != pte_write(huge_ptep_get(ptep)))
+		return 1;
+
+	for (i = 0; i < ncontig; i++) {
+		pte_t orig_pte = huge_ptep_get(ptep + i);
+
+		if (pte_dirty(pte) != pte_dirty(orig_pte))
+			return 1;
+
+		if (pte_young(pte) != pte_young(orig_pte))
+			return 1;
+	}
+
+	return 0;
+}
+
 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       unsigned long addr, pte_t *ptep,
 			       pte_t pte, int dirty)
 {
-	int ncontig, i, changed = 0;
+	int ncontig, i;
 	size_t pgsize = 0;
 	unsigned long pfn = pte_pfn(pte), dpfn;
 	pgprot_t hugeprot;
@@ -336,19 +368,23 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 	ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize);
 	dpfn = pgsize >> PAGE_SHIFT;
 
+	if (!__cont_access_flags_changed(ptep, pte, ncontig))
+		return 0;
+
 	orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
-	if (!pte_same(orig_pte, pte))
-		changed = 1;
 
-	/* Make sure we don't lose the dirty state */
+	/* Make sure we don't lose the dirty or young state */
 	if (pte_dirty(orig_pte))
 		pte = pte_mkdirty(pte);
 
+	if (pte_young(orig_pte))
+		pte = pte_mkyoung(pte);
+
 	hugeprot = pte_pgprot(pte);
 	for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
 		set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot));
 
-	return changed;
+	return 1;
 }
 
 void huge_ptep_set_wrprotect(struct mm_struct *mm,