1 files changed, 47 insertions, 12 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 605f7fe9a143..a46d9b75880b 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2452,6 +2452,51 @@ static int prctl_get_auxv(void __user *addr, unsigned long len)
 	return sizeof(mm->saved_auxv);
 }
 
+static int prctl_get_thp_disable(unsigned long arg2, unsigned long arg3,
+				 unsigned long arg4, unsigned long arg5)
+{
+	struct mm_struct *mm = current->mm;
+
+	if (arg2 || arg3 || arg4 || arg5)
+		return -EINVAL;
+
+	/* If disabled, we return "1 | flags", otherwise 0. */
+	if (mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm))
+		return 1;
+	else if (mm_flags_test(MMF_DISABLE_THP_EXCEPT_ADVISED, mm))
+		return 1 | PR_THP_DISABLE_EXCEPT_ADVISED;
+	return 0;
+}
+
+static int prctl_set_thp_disable(bool thp_disable, unsigned long flags,
+				 unsigned long arg4, unsigned long arg5)
+{
+	struct mm_struct *mm = current->mm;
+
+	if (arg4 || arg5)
+		return -EINVAL;
+
+	/* Flags are only allowed when disabling. */
+	if ((!thp_disable && flags) || (flags & ~PR_THP_DISABLE_EXCEPT_ADVISED))
+		return -EINVAL;
+	if (mmap_write_lock_killable(current->mm))
+		return -EINTR;
+	if (thp_disable) {
+		if (flags & PR_THP_DISABLE_EXCEPT_ADVISED) {
+			mm_flags_clear(MMF_DISABLE_THP_COMPLETELY, mm);
+			mm_flags_set(MMF_DISABLE_THP_EXCEPT_ADVISED, mm);
+		} else {
+			mm_flags_set(MMF_DISABLE_THP_COMPLETELY, mm);
+			mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm);
+		}
+	} else {
+		mm_flags_clear(MMF_DISABLE_THP_COMPLETELY, mm);
+		mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm);
+	}
+	mmap_write_unlock(current->mm);
+	return 0;
+}
+
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 		unsigned long, arg4, unsigned long, arg5)
 {
@@ -2625,20 +2670,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 			return -EINVAL;
 		return task_no_new_privs(current) ? 1 : 0;
 	case PR_GET_THP_DISABLE:
-		if (arg2 || arg3 || arg4 || arg5)
-			return -EINVAL;
-		error = !!mm_flags_test(MMF_DISABLE_THP, me->mm);
+		error = prctl_get_thp_disable(arg2, arg3, arg4, arg5);
 		break;
 	case PR_SET_THP_DISABLE:
-		if (arg3 || arg4 || arg5)
-			return -EINVAL;
-		if (mmap_write_lock_killable(me->mm))
-			return -EINTR;
-		if (arg2)
-			mm_flags_set(MMF_DISABLE_THP, me->mm);
-		else
-			mm_flags_clear(MMF_DISABLE_THP, me->mm);
-		mmap_write_unlock(me->mm);
+		error = prctl_set_thp_disable(arg2, arg3, arg4, arg5);
 		break;
 	case PR_MPX_ENABLE_MANAGEMENT:
 	case PR_MPX_DISABLE_MANAGEMENT: