diff --git a/libc/kernel/common/asm-generic/pgtable.h b/libc/kernel/common/asm-generic/pgtable.h
index a21cdba..dadf386 100644
--- a/libc/kernel/common/asm-generic/pgtable.h
+++ b/libc/kernel/common/asm-generic/pgtable.h
@@ -7,89 +7,99 @@
  ***   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_PGTABLE_H
 #define _ASM_GENERIC_PGTABLE_H
-
 #ifndef __HAVE_ARCH_PTEP_ESTABLISH
-
 #ifndef __HAVE_ARCH_SET_PTE_ATOMIC
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define ptep_establish(__vma, __address, __ptep, __entry)  do {   set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);   flush_tlb_page(__vma, __address);  } while (0)
 #else
 #define ptep_establish(__vma, __address, __ptep, __entry)  do {   set_pte_atomic(__ptep, __entry);   flush_tlb_page(__vma, __address);  } while (0)
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
-
 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
-
 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty)  do {   set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);   flush_tlb_page(__vma, __address);  } while (0)
 #endif
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define ptep_test_and_clear_young(__vma, __address, __ptep)  ({   pte_t __pte = *(__ptep);   int r = 1;   if (!pte_young(__pte))   r = 0;   else   set_pte_at((__vma)->vm_mm, (__address),   (__ptep), pte_mkold(__pte));   r;  })
 #endif
-
 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define ptep_clear_flush_young(__vma, __address, __ptep)  ({   int __young;   __young = ptep_test_and_clear_young(__vma, __address, __ptep);   if (__young)   flush_tlb_page(__vma, __address);   __young;  })
 #endif
-
 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 #define ptep_test_and_clear_dirty(__vma, __address, __ptep)  ({   pte_t __pte = *__ptep;   int r = 1;   if (!pte_dirty(__pte))   r = 0;   else   set_pte_at((__vma)->vm_mm, (__address), (__ptep),   pte_mkclean(__pte));   r;  })
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
-
 #ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
 #define ptep_clear_flush_dirty(__vma, __address, __ptep)  ({   int __dirty;   __dirty = ptep_test_and_clear_dirty(__vma, __address, __ptep);   if (__dirty)   flush_tlb_page(__vma, __address);   __dirty;  })
 #endif
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
 #define ptep_get_and_clear(__mm, __address, __ptep)  ({   pte_t __pte = *(__ptep);   pte_clear((__mm), (__address), (__ptep));   __pte;  })
 #endif
-
 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define ptep_get_and_clear_full(__mm, __address, __ptep, __full)  ({   pte_t __pte;   __pte = ptep_get_and_clear((__mm), (__address), (__ptep));   __pte;  })
 #endif
-
 #ifndef __HAVE_ARCH_PTE_CLEAR_FULL
 #define pte_clear_full(__mm, __address, __ptep, __full)  do {   pte_clear((__mm), (__address), (__ptep));  } while (0)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
-
 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 #define ptep_clear_flush(__vma, __address, __ptep)  ({   pte_t __pte;   __pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep);   flush_tlb_page(__vma, __address);   __pte;  })
 #endif
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 struct mm_struct;
 #endif
 #ifndef __HAVE_ARCH_PTE_SAME
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pte_same(A,B) (pte_val(A) == pte_val(B))
 #endif
 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
 #define page_test_and_clear_dirty(page) (0)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pte_maybe_dirty(pte) pte_dirty(pte)
 #else
 #define pte_maybe_dirty(pte) (1)
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 #define page_test_and_clear_young(page) (0)
 #endif
 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
 #endif
 #ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
 #define lazy_mmu_prot_update(pte) do { } while (0)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
 #ifndef __HAVE_ARCH_MOVE_PTE
 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define pgd_addr_end(addr, end)  ({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;   (__boundary - 1 < (end) - 1)? __boundary: (end);  })
 #ifndef pud_addr_end
 #define pud_addr_end(addr, end)  ({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;   (__boundary - 1 < (end) - 1)? __boundary: (end);  })
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #ifndef pmd_addr_end
 #define pmd_addr_end(addr, end)  ({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;   (__boundary - 1 < (end) - 1)? __boundary: (end);  })
 #endif
 #ifndef __ASSEMBLY__
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
 #endif