CONFIG_KEXEC_JUMP is not available for the selected architecture x86.
Result is shown for architecture sh

kexec jump (EXPERIMENTAL)

configname: CONFIG_KEXEC_JUMP

Linux Kernel Configuration
└─>Kernel features
└─>kexec jump (EXPERIMENTAL)
In linux kernel since version 2.6.27 (release Date: 2008-10-09)
Jump between original kernel and kexeced kernel and invoke
code via KEXEC