CONFIG_4xx is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

CONFIG_4xx (not configurable)

modulename: shared.ko

configname: CONFIG_4xx

Linux Kernel Configuration
└─>Processor support
└─>4xx
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
source code:
arch/powerpc/mm/ptdump/shared.c
depends
CONFIG_40x or CONFIG_44x