Remove the kernel mapping in user mode

modulename: pti.ko

configname: CONFIG_PAGE_TABLE_ISOLATION

Linux Kernel Configuration
└─>Security options
└─>Remove the kernel mapping in user mode
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This feature reduces the number of hardware side channels by
ensuring that the majority of kernel addresses are not mapped
into userspace.

See Documentation/x86/pti.txt for more details.

source code:
arch/x86/mm/pti.c