KGDB: use kgdb over the serial console

modulename: kgdboc.ko

configname: CONFIG_KGDB_SERIAL_CONSOLE

Linux Kernel Configuration
└─>KGDB: kernel debugger
└─>KGDB: use kgdb over the serial console
In linux kernel since version 2.6.26 (release Date: 2008-07-13)  
Share a serial console with kgdb. Sysrq-g must be used
to break in initially.

source code:
drivers/tty/serial/kgdboc.c