diff --git a/libc/kernel/arch-x86/asm/mman.h b/libc/kernel/arch-x86/asm/mman.h
index 7eda319..b0b4e1d 100644
--- a/libc/kernel/arch-x86/asm/mman.h
+++ b/libc/kernel/arch-x86/asm/mman.h
@@ -7,24 +7,29 @@
  ***   structures, and macros generated from the original header, and thus,
  ***   contains no copyrightable information.
  ***
+ ***   To edit the content of this header, modify the corresponding
+ ***   source file (e.g. under external/kernel-headers/original/) then
+ ***   run bionic/libc/kernel/tools/update_all.py
+ ***
+ ***   Any manual change here will be lost the next time this script will
+ ***   be run. You've been warned!
+ ***
  ****************************************************************************
  ****************************************************************************/
 #ifndef _ASM_X86_MMAN_H
 #define _ASM_X86_MMAN_H
-
 #include <asm-generic/mman.h>
-
 #define MAP_32BIT 0x40  
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define MAP_GROWSDOWN 0x0100  
 #define MAP_DENYWRITE 0x0800  
 #define MAP_EXECUTABLE 0x1000  
 #define MAP_LOCKED 0x2000  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define MAP_NORESERVE 0x4000  
 #define MAP_POPULATE 0x8000  
 #define MAP_NONBLOCK 0x10000  
-
 #define MCL_CURRENT 1  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define MCL_FUTURE 2  
-
 #endif