CONFIG_CPU_XSC3 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_CPU_XSC3 (not configurable)

modulename: copypage-xsc3.ko

and/or

proc-xsc3.ko

and/or

xscale-cp0.ko

configname: CONFIG_CPU_XSC3

Linux Kernel Configuration
└─>CPU_XSC3
In linux kernel since version 2.6.17 (release Date: 2006-06-17)  
source code:
arch/arm/mm/copypage-xsc3.c

is selected by
CONFIG_CACHE_XSC3L2