License: Credit me if you use it.
This is a open code replacement for Intel's binary only GDB server that comes as part of the 'Intel UEFI Development Kit Debugger Tool'. Since that tool is Intel x86/64 Linux/Windows only this allows more flexibility.
E.g. you can run this on any ARM based SoC with python3 and a USB OTG port connected directly to your target via a USB2.0 EHCI Debug port using the Linux USB OTG Debug Port gadget. You can then connect to that target remotely from your build box, etc.
This also allows you to tweak the debugger itself. I've already added some additional functionality here to assist when using SourceLevelDebugPkg on non-EDK2 (i.e. no source available) firmwares such as AMI Aptio IV.
Combined with the gdb-symbol-maker here: https://github.com/night199uk/gdb-symbol-maker
This will allow you to do rudimentary Source Level Debugging on firmwares you don't have the source code for.
Change: #define DEBUG_AGENT_REVISION DEBUG_AGENT_REVISION_04
To: #define DEBUG_AGENT_REVISION DEBUG_AGENT_REVISION_03
This is to disable Compression, which we don't support (yet).
You will also need to set up SourceLevelDebugPkg as you need for your target. I have successfully used SourceLevelDebugPkg using both USB2 and Serial. USB2 (EHCI Debug) is a little complex, but unlike much FUD on the internet, it does work fine.
Include SourceLevelDebugPkg in your build by including the .inf in your .dsc and .fdf. or
Build a DebugAgentDxe.ffs manually and use e.g. UEFITool or MMTool to inject it into your BIOS (e.g. AMI, Phoenix, etc).
Edit the serial port / PTS specified in server.py to point to your serial port, CDC ACM device (USB2 Debug Gadget/EHCI Dongle, etc) or PseudoTTY (OvmfPkg/qemu).
Reboot your target. The gdb server only starts listening after it succesfully handshakes with the target.
Build a working GDB on your debug host EDK2 (build box, etc): You will need to use --target x86_64-w64-mingw32 when configuring GDB.
Connect remotely from your host (build box) using gdb: target remote x.x.x.x:1234
Enjoy debugging UEFI.