diff --git a/libc/kernel/common/linux/mc146818rtc.h b/libc/kernel/common/linux/mc146818rtc.h
index 74436ea..d606489 100644
--- a/libc/kernel/common/linux/mc146818rtc.h
+++ b/libc/kernel/common/linux/mc146818rtc.h
@@ -7,73 +7,74 @@
  ***   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 _MC146818RTC_H
 #define _MC146818RTC_H
-
 #include <asm/io.h>
 #include <linux/rtc.h>  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #include <asm/mc146818rtc.h>  
-
 #define RTC_SECONDS 0
 #define RTC_SECONDS_ALARM 1
 #define RTC_MINUTES 2
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_MINUTES_ALARM 3
 #define RTC_HOURS 4
 #define RTC_HOURS_ALARM 5
-
 #define RTC_ALARM_DONT_CARE 0xC0
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_DAY_OF_WEEK 6
 #define RTC_DAY_OF_MONTH 7
 #define RTC_MONTH 8
 #define RTC_YEAR 9
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_REG_A 10
 #define RTC_REG_B 11
 #define RTC_REG_C 12
 #define RTC_REG_D 13
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_FREQ_SELECT RTC_REG_A
-
 #define RTC_UIP 0x80
 #define RTC_DIV_CTL 0x70
-
 #define RTC_REF_CLCK_4MHZ 0x00
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_REF_CLCK_1MHZ 0x10
 #define RTC_REF_CLCK_32KHZ 0x20
-
 #define RTC_DIV_RESET1 0x60
 #define RTC_DIV_RESET2 0x70
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_RATE_SELECT 0x0F
-
 #define RTC_CONTROL RTC_REG_B
 #define RTC_SET 0x80  
 #define RTC_PIE 0x40  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_AIE 0x20  
 #define RTC_UIE 0x10  
 #define RTC_SQWE 0x08  
 #define RTC_DM_BINARY 0x04  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_24H 0x02  
 #define RTC_DST_EN 0x01  
-
 #define RTC_INTR_FLAGS RTC_REG_C
-
 #define RTC_IRQF 0x80  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_PF 0x40
 #define RTC_AF 0x20
 #define RTC_UF 0x10
-
 #define RTC_VALID RTC_REG_D
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define RTC_VRT 0x80  
-
 #ifndef ARCH_RTC_LOCATION
-
 #define RTC_IO_EXTENT 0x8
 #define RTC_IOMAPPED 1  
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
-
 #endif