For the best possible debugging experience it's a good idea to compile GDB specifically for Zeke. The following configure flags should work the best with Zeke and its GDB Python scripts.
./configure --with-python=python3.4 --host=x86_64-linux-gnu --target=arm-none-eabi
If you wish to use Zekedock, which you should as Zeke only works with very specific versions of build and debug tools, it already includes GDB 7.10.
While running Zeke in QEMU gdb can be started by executing rm-none-eabi-gdb
which will automatically attach to the Zeke in QEMU, thanks to
.gdbinit. It might be helpful to run these in screen when
using the Docker image. screen is preinstalled in the Docker image.
To get debugging symbols for the kernel (and user space executables) add the
-g flag to CCFLAGS in Kconfig: Build Config.
Debugging the kernel is probably easiest when Zeke is running in QEMU. If you
have QEMU listening as a GDB server already (-s option), it's enough to just
execute GDB with the repository root as a working directory. This way GDB will
read .gdbinit, and thus connecting to the server and loading all Zeke specific
debugging utils.
Debugging user space executables is currently not supported but core dump files written by the kernel are mostly GDB compatible. Most of the tools capable of reading Linux and/or freeBSD elf core files can also parse core files written by Zeke.
print current_process_id
print current_thread.idset $pc = 0xYYY
set $sp = 0xXXXprint/x current_thread.kstack_region.b_data
$2 = 0x403000
set $sp = 0x403f28 # PC should have been printed to the console
set $pc = 0x0002311c