1 files changed, 12 insertions, 1 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 019afdf50b1a..0f1e9ff6bc12 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -1256,6 +1256,15 @@ static int __s390_enable_skey(pte_t *pte, unsigned long addr,
         pgste_t pgste;
 
         pgste = pgste_get_lock(pte);
+        /*
+         * Remove all zero page mappings,
+         * after establishing a policy to forbid zero page mappings
+         * following faults for that page will get fresh anonymous pages
+         */
+        if (is_zero_pfn(pte_pfn(*pte))) {
+                ptep_flush_direct(walk->mm, addr, pte);
+                pte_val(*pte) = _PAGE_INVALID;
+        }
         /* Clear storage key */
         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
                               PGSTE_GR_BIT | PGSTE_GC_BIT);
@@ -1274,9 +1283,11 @@ void s390_enable_skey(void)
         down_write(&mm->mmap_sem);
         if (mm_use_skey(mm))
                 goto out_up;
+
+        mm->context.use_skey = 1;
+
         walk.mm = mm;
         walk_page_range(0, TASK_SIZE, &walk);
-        mm->context.use_skey = 1;
 
 out_up:
         up_write(&mm->mmap_sem);