CONFIG_HAVE_FUNCTION_GRAPH_FREGS (not configurable)

configname: CONFIG_HAVE_FUNCTION_GRAPH_FREGS

Linux Kernel Configuration
└─>Kernel hacking
└─>HAVE_FUNCTION_GRAPH_FREGS
In linux kernel since version 6.6.78 (release Date: 2025-02-17)  
is selected by
CONFIG_FPROBE