CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE (not configurable)

configname: CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE

Linux Kernel Configuration
└─>Kernel Features
└─>ARM errata workarounds via the alternatives framework
└─>ARM64_WORKAROUND_TSB_FLUSH_FAILURE
In linux kernel since version 5.2 (release Date: 2019-07-07)