Hey Phil, sorry for the confusion.
I personally prefer to run the make run_openocd and run_gdb targets separately, the “run_debug” target doesn’t work if you want to halt. So let’s ignore run_debug for now.
You will need two terminal windows.
In one, just run make run_openocd. Then just leave it there. All this has done is launch the OpenOCD process, which talks to the HiFive1 board and halts the running code.
In the other window, run make run_gdb PROGRAM=demo_gpio (for example). This launches the GDB process, but you need to actually get it talking to the openOCD process:
gdb > target extended-remote localhost:3333
Once you do that, you’ll be able to run the usual suite of GDB commands.
(Yes, we should document the magical incantation above better).