[coreboot] Debugging using gdb

Hello Everybody,

I am new to coreboot build environment and need your help in using gdb with coreboot.

I want to use gdb to take a closer look at the stages in coreboot and the order they are executed in. I also want to single step through the code to see what functions are being called in each stage and during transition from one stage to another. Firstly, I am not even sure if gdb works during transition. Does it?

These are the steps I followed:

1. First I set up the coreboot environment by following this tutorial. https://doc.coreboot.org/tutorial/part1.html. (I also enabled Gdb Wait by going to Debugging menu in coreboot's configuration.)

2. Then I ran the image on qemu 
         $  qemu-system-x86_64 -bios build/coreboot.rom -serial stdio -s -S

3.  In another terminal, I started gdb and entered the following command
         $  target remote localhost:1234

4.  From here, I am able to single step using 'si' but I am not able to set a breakpoint using 'break' at say romstage.c or hardwaremain.c. 
     I get the following error:
                ''No symbol table is loaded.  Use the "file" command.
                Make breakpoint pending on future shared library load? (y or [n])''

Can anyone tell me where I went wrong?

Thanks,

Harshit