1 files changed, 23 insertions, 21 deletions

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index afa836014076..c9f3d8a52756 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -18,6 +18,8 @@
 static inline int init_new_context(struct task_struct *tsk,
 				   struct mm_struct *mm)
 {
+	unsigned long asce_type, init_entry;
+
 	spin_lock_init(&mm->context.lock);
 	INIT_LIST_HEAD(&mm->context.pgtable_list);
 	INIT_LIST_HEAD(&mm->context.gmap_list);
@@ -26,7 +28,6 @@ static inline int init_new_context(struct task_struct *tsk,
 	atomic_set(&mm->context.is_protected, 0);
 	mm->context.gmap_asce = 0;
 	mm->context.flush_mm = 0;
-	mm->context.compat_mm = test_thread_flag(TIF_31BIT);
 #ifdef CONFIG_PGSTE
 	mm->context.alloc_pgste = page_table_allocate_pgste ||
 		test_thread_flag(TIF_PGSTE) ||
@@ -37,33 +38,34 @@ static inline int init_new_context(struct task_struct *tsk,
 	mm->context.allow_gmap_hpage_1m = 0;
 #endif
 	switch (mm->context.asce_limit) {
-	case _REGION2_SIZE:
+	default:
 		/*
-		 * forked 3-level task, fall through to set new asce with new
-		 * mm->pgd
+		 * context created by exec, the value of asce_limit can
+		 * only be zero in this case
 		 */
-	case 0:
-		/* context created by exec, set asce limit to 4TB */
-		mm->context.asce_limit = STACK_TOP_MAX;
-		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
-				   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
+		VM_BUG_ON(mm->context.asce_limit);
+		/* continue as 3-level task */
+		mm->context.asce_limit = _REGION2_SIZE;
+		fallthrough;
+	case _REGION2_SIZE:
+		/* forked 3-level task */
+		init_entry = _REGION3_ENTRY_EMPTY;
+		asce_type = _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;
+	case TASK_SIZE_MAX:
+		/* forked 5-level task */
+		init_entry = _REGION1_ENTRY_EMPTY;
+		asce_type = _ASCE_TYPE_REGION1;
 		break;
 	case _REGION1_SIZE:
-		/* forked 4-level task, set new asce with new mm->pgd */
-		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
-				   _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
+		/* forked 4-level task */
+		init_entry = _REGION2_ENTRY_EMPTY;
+		asce_type = _ASCE_TYPE_REGION2;
 		break;
-	case _REGION3_SIZE:
-		/* forked 2-level compat task, set new asce with new mm->pgd */
-		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
-				   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
 	}
-	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
+	mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+			   _ASCE_USER_BITS | asce_type;
+	crst_table_init((unsigned long *) mm->pgd, init_entry);
 	return 0;
 }