CONFIG_GENERIC_VDSO_TIME_NS (not configurable)

configname: CONFIG_GENERIC_VDSO_TIME_NS

Linux Kernel Configuration
└─>Library routines
└─>GENERIC_VDSO_TIME_NS
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Selected by architectures which support time namespaces in the
VDSO