CONFIG_MACH_GENERIC_CORE is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_MACH_GENERIC_CORE (not configurable)

modulename: init.ko

and/or

irq.ko

and/or

proc.ko

configname: CONFIG_MACH_GENERIC_CORE

Linux Kernel Configuration
└─>MACH_GENERIC_CORE
In linux kernel since version 6.1.89 (release Date: 2024-04-29)  
source code:
arch/mips/generic/init.c