diff --git a/libc/kernel/uapi/linux/membarrier.h b/libc/kernel/uapi/linux/membarrier.h
index e9edbaa..2f5ea7d 100644
--- a/libc/kernel/uapi/linux/membarrier.h
+++ b/libc/kernel/uapi/linux/membarrier.h
@@ -21,5 +21,7 @@
 enum membarrier_cmd {
   MEMBARRIER_CMD_QUERY = 0,
   MEMBARRIER_CMD_SHARED = (1 << 0),
+  MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
+  MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
 };
 #endif