CONFIG_EXPOLINE is not available for thedefaultarchitecture x86.
Result is shown for architecture s390

Avoid speculative indirect branches in the kernel

configname: CONFIG_EXPOLINE

Linux Kernel Configuration
└─>Processor type and features
└─>Avoid speculative indirect branches in the kernel
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Compile the kernel with the expoline compiler options to guard
against kernel-to-user data leaks by avoiding speculative indirect
branches.
Requires a compiler with -mindirect-branch=thunk support for full
protection. The kernel may run slower.

If unsure, say N.

depends
CONFIG_cc-option