EFI Bootloader Control

modulename: efibc.ko


Linux Kernel Configuration
└─>Device Drivers
└─>Firmware Drivers
└─>EFI (Extensible Firmware Interface) Support
└─>EFI Bootloader Control
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This module installs a reboot hook, such that if reboot() is
invoked with a string argument NNN, "NNN" is copied to the
"LoaderEntryOneShot" EFI variable, to be read by the
bootloader. If the string matches one of the boot labels
defined in its configuration, the bootloader will boot once
to that label. The "LoaderEntryRebootReason" EFI variable is
set with the reboot reason: "reboot" or "shutdown". The
bootloader reads this reboot reason and takes particular
action according to its policy.

source code: