CONFIG_SELFMOD is not available for thedefaultarchitecture x86.
Result is shown for architecture microblaze
default or selected kernelversion does not have config value CONFIG_SELFMOD.
Result is shown for kernelversion 6.2.5

Use self modified code for intc/timer

modulename: selfmod.ko

configname: CONFIG_SELFMOD

Linux Kernel Configuration
└─>Platform options
└─>Use self modified code for intc/timer
In linux kernel since version 2.6.30 (release Date: 2009-06-09)  
This choice enables self-modified code for interrupt controller
and timer.

source code:
depends
CONFIG_EXPERIMENTAL
CONFIG_NO_MMU