README.debug

Debugging Instructions
======================

To build for debugging, append " -g" to CFLAGS when running configure.

After building, start the kernel and append the '-S' and '-s' flags to the qemu
call, to instruct the emulator to pause execution at the first instruction and
wait for a debugger to attach at localhost port 1234:

  $> qemu-system-arm -M versatilepb -m 128M -nographic -kernel ninjastorms -S -s

Next, in another terminal, start arm-none-eabi-gdb

  $> arm-none-eabi-gdb
  (gdb)

on the gdb command line, choose the kernel binary containing the debug info:

  (gdb) file ninjastorms
  Reading symbols from ninjastorms...
  ...

and attach the debugger to the virtual machine:

  (gdb) target remote localhost:1234
  Remote debugging using localhost:1234
  Start () at kernel/boot/start.S:27
  27	  ldr   sp, =__bss_end

the kernel can now be debugged using gdb like a regular C program.