Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Martin Schwidefsky:
 "Three more bug fixes for v4.13.

  The two memory management related fixes are quite new, they fix kernel
  crashes that can be triggered by user space.

  The third commit fixes a bug in the vfio ccw translation code"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/mm: fix BUG_ON in crst_table_upgrade
  s390/mm: fork vs. 5 level page tabel
  vfio: ccw: fix bad ptr math for TIC cda translation

arch/s390/include/asm/mmu_context.h

@@ -44,6 +44,11 @@ static inline int init_new_context(struct task_struct *tsk,
 		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
 				   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
 		break;
+	case -PAGE_SIZE:
+		/* forked 5-level task, set new asce with new_mm->pgd */
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+			_ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+		break;
 	case 1UL << 53:
 		/* forked 4-level task, set new asce with new mm->pgd */
 		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |

arch/s390/mm/mmap.c

@@ -119,7 +119,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		return addr;
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm, addr + len);
 		if (rc)
 			return (unsigned long) rc;
@@ -183,7 +184,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	}
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm, addr + len);
 		if (rc)
 			return (unsigned long) rc;

drivers/s390/cio/vfio_ccw_cp.c

@@ -481,7 +481,7 @@ static int ccwchain_fetch_tic(struct ccwchain *chain,
 		ccw_tail = ccw_head + (iter->ch_len - 1) * sizeof(struct ccw1);
 
 		if ((ccw_head <= ccw->cda) && (ccw->cda <= ccw_tail)) {
-			ccw->cda = (__u32) (addr_t) (iter->ch_ccw +
+			ccw->cda = (__u32) (addr_t) (((char *)iter->ch_ccw) +
 						     (ccw->cda - ccw_head));
 			return 0;
 		}