diff --git a/libc/kernel/common/asm-generic/pgtable-nopud.h b/libc/kernel/common/asm-generic/pgtable-nopud.h
index 585f816..e940ae4 100644
--- a/libc/kernel/common/asm-generic/pgtable-nopud.h
+++ b/libc/kernel/common/asm-generic/pgtable-nopud.h
@@ -7,33 +7,40 @@
  ***   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 _PGTABLE_NOPUD_H
 #define _PGTABLE_NOPUD_H
-
 #ifndef __ASSEMBLY__
-
 #define __PAGETABLE_PUD_FOLDED
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 typedef struct { pgd_t pgd; } pud_t;
-
 #define PUD_SHIFT PGDIR_SHIFT
 #define PTRS_PER_PUD 1
 #define PUD_SIZE (1UL << PUD_SHIFT)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define PUD_MASK (~(PUD_SIZE-1))
-
 #define pud_ERROR(pud) (pgd_ERROR((pud).pgd))
 #define pgd_populate(mm, pgd, pud) do { } while (0)
 #define set_pgd(pgdptr, pgdval) set_pud((pud_t *)(pgdptr), (pud_t) { pgdval })
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pud_val(x) (pgd_val((x).pgd))
 #define __pud(x) ((pud_t) { __pgd(x) } )
 #define pgd_page(pgd) (pud_page((pud_t){ pgd }))
 #define pgd_page_kernel(pgd) (pud_page_kernel((pud_t){ pgd }))
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pud_alloc_one(mm, address) NULL
 #define pud_free(x) do { } while (0)
 #define __pud_free_tlb(tlb, x) do { } while (0)
 #undef pud_addr_end
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pud_addr_end(addr, end) (end)
 #endif
 #endif