CONFIG_HARDEN_BRANCH_HISTORY is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
Harden Spectre style attacks against branch history
configname: CONFIG_HARDEN_BRANCH_HISTORY
Linux Kernel Configuration
└─>Harden Spectre style attacks against branch history
In linux kernel since version 4.9.3 (release Date: 2017-01-12)
Speculation attacks against some high-performance processors can
make use of branch history to influence future speculation. When
taking an exception, a sequence of branches overwrites the branch
history, or branch history is invalidated.
make use of branch history to influence future speculation. When
taking an exception, a sequence of branches overwrites the branch
history, or branch history is invalidated.