--- zzzz-none-000/linux-4.4.271/arch/arm/include/asm/system_misc.h 2021-06-03 06:22:09.000000000 +0000 +++ maple-fsgw-759/linux-4.4.271/arch/arm/include/asm/system_misc.h 2023-12-20 10:37:00.000000000 +0000 @@ -36,6 +36,7 @@ #define UDBG_BUS (1 << 4) extern unsigned int user_debug; +extern char* (*arch_read_hardware_id)(void); #endif /* !__ASSEMBLY__ */