Here's the first patch that introduces the context:
+choice
+ prompt "Method for KGDB communication"
+ depends on KGDB
+ default KGDB_ONLY_MODULES
+ help
+ There are a number of different ways in which you can communicate
+ with KGDB. The most common is via serial, with the 8250 driver
+ (should your hardware have an 8250, or ns1655x style uart).
+ Another option is to use the NETPOLL framework and UDP, should
+ your ethernet card support this. Other options may exist.
+ You can elect to have one core I/O driver that is built into the
+ kernel for debugging as the kernel is booting, or using only
+ kernel modules.
+
Here's the hunk that modifies it:
***************
*** 212,217 ****
Use only kernel modules to configure KGDB I/O after the
kernel is booted.
config KGDB_MPSC
bool "KGDB on MV64x60 MPSC"
depends on SERIAL_MPSC
--- 212,225 ----
Use only kernel modules to configure KGDB I/O after the
kernel is booted.
+ config KGDB_8250_NOMODULE
+ bool "KGDB: On generic serial port (8250)"
+ select KGDB_8250
+ help
+ Uses generic serial port (8250) to communicate with the host
+ GDB. This is independent of the normal (SERIAL_8250) driver
+ for this chipset.
+
config KGDB_MPSC
bool "KGDB on MV64x60 MPSC"
depends on SERIAL_MPSC