diff --git a/libc/kernel/common/asm-generic/ioctl.h b/libc/kernel/common/asm-generic/ioctl.h
index cba2b8e..f987314 100644
--- a/libc/kernel/common/asm-generic/ioctl.h
+++ b/libc/kernel/common/asm-generic/ioctl.h
@@ -7,52 +7,58 @@
  ***   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_GENERIC_IOCTL_H
 #define _ASM_GENERIC_IOCTL_H
-
 #define _IOC_NRBITS 8
 #define _IOC_TYPEBITS 8
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IOC_SIZEBITS 14
 #define _IOC_DIRBITS 2
-
 #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
 #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
 #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
-
 #define _IOC_NRSHIFT 0
 #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
 #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
-
 #define _IOC_NONE 0U
 #define _IOC_WRITE 1U
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IOC_READ 2U
-
 #define _IOC(dir,type,nr,size)   (((dir) << _IOC_DIRSHIFT) |   ((type) << _IOC_TYPESHIFT) |   ((nr) << _IOC_NRSHIFT) |   ((size) << _IOC_SIZESHIFT))
-
 extern unsigned int __invalid_size_argument_for_IOC;
 #define _IOC_TYPECHECK(t)   ((sizeof(t) == sizeof(t[1]) &&   sizeof(t) < (1 << _IOC_SIZEBITS)) ?   sizeof(t) : __invalid_size_argument_for_IOC)
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
 #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
 #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
 #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
-
 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
-
 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif