On Thu, Aug 21, 2025 at 5:05 PM Alkallas, Mouhanad <
Mouhanad.Alkallas@amd.com> wrote:
> The proposal is to add a packet “J” for customization in privately
> defined KGDB IO Module.
>
> Packet format would “J <custom data>”, instead of gdbstub.c handling
> the packet, it would forward the call to the attached KGDB IO Module
> to service the packet.

I'm not familiar with KGDB specifically, but a common solution used by
other stubs is to use the "qRcmd" packet for custom commands. I know the
Black Magic debug probe uses this to allow the user to scan the JTAG chain
it's connected to and a few other things.

The documentation for KGDB [1] indicates it already uses this packet for
some commands. Is it possible to hook in to that existing mechanism? Or is
that unsuitable for the problem you're trying to solve?

 [1]:
https://www.kernel.org/doc/html/v4.14/dev-tools/kgdb.html#running-kdb-commands-from-gdb

 -Aaron