KGDB on ARMv7

Hi,

   I am looking at implementation of KGDB support on kernel for ARMv7.
I want to know about kernel implementation for step & next commands
debugging for ARMv7
Does it use HW step debugging?

Because command 's' from GDB host is not processed like other
commands. I want to find out
what is the special processing done by ARM/Kernel for this?

Thanks & Regards
Vijay