diff --git a/libc/kernel/arch-x86/asm/cacheflush.h b/libc/kernel/arch-x86/asm/cacheflush.h
index 028277b..92a6458 100644
--- a/libc/kernel/arch-x86/asm/cacheflush.h
+++ b/libc/kernel/arch-x86/asm/cacheflush.h
@@ -7,28 +7,35 @@
  ***   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_CACHEFLUSH_H
 #define _ASM_X86_CACHEFLUSH_H
-
 #include <linux/mm.h>
-
 #define flush_cache_all() do { } while (0)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define flush_cache_mm(mm) do { } while (0)
 #define flush_cache_dup_mm(mm) do { } while (0)
 #define flush_cache_range(vma, start, end) do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn) do { } while (0)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define flush_dcache_page(page) do { } while (0)
 #define flush_dcache_mmap_lock(mapping) do { } while (0)
 #define flush_dcache_mmap_unlock(mapping) do { } while (0)
 #define flush_icache_range(start, end) do { } while (0)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define flush_icache_page(vma,pg) do { } while (0)
 #define flush_icache_user_range(vma,pg,adr,len) do { } while (0)
 #define flush_cache_vmap(start, end) do { } while (0)
 #define flush_cache_vunmap(start, end) do { } while (0)
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define copy_to_user_page(vma, page, vaddr, dst, src, len)   memcpy(dst, src, len)
 #define copy_from_user_page(vma, page, vaddr, dst, src, len)   memcpy(dst, src, len)
-
 #endif