CONFIG_SYS_HAS_CPU_LOONGSON3 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips
default or selected kernelversion does not have config value CONFIG_SYS_HAS_CPU_LOONGSON3.
Result is shown for kernelversion 6.9.9

CONFIG_SYS_HAS_CPU_LOONGSON3 (not configurable)

configname: CONFIG_SYS_HAS_CPU_LOONGSON3

Linux Kernel Configuration
└─>CPU selection
└─>SYS_HAS_CPU_LOONGSON3
In linux kernel since version 3.15 (release Date: 2014-06-08)