CONFIG_GENERIC_TIME_VSYSCALL is not available for thedefaultarchitecture x86.
Result is shown for architecture tile

CONFIG_GENERIC_TIME_VSYSCALL (not configurable)

configname: CONFIG_GENERIC_TIME_VSYSCALL

Linux Kernel Configuration
└─>GENERIC_TIME_VSYSCALL
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
is depended by
CONFIG_VDSO