debugging kernel with bochs

[vjain20]

Hi,

I am following the JamesM tutorial for writing an OS. I want to debug the kernel
but when I add the debug option (-g) to the Makefile and compile and run the new binary with bochs it keeps on restarting.
I added the -g option to both CFLAGS and ASFLAGS (for nasm). Normally (without -g flag) the kernel would just print
'Hello world' and then spin in infinite loop. Please help.


- Thanks

[turdus]

I'm not sure where you're using -g. For compiling bochs it's unecessary (because it's not bochs you want to debug), and as for your kernel you should be able to debug without it. You won't see the name of the interrupted function (and the source file with line number), just a couple hex numbers, but it should work. If you want symbol names to be imported, you have to specify debug_symbols in bochsrc:
http://bochs.sourceforge.net/doc/docboo ... ml#AEN1986

[vjain20]

Thanks for replying! I should have mentioned that I am trying to debug the kernel using
gdb through remote debugging. For that I will have to compile it using -g option.
So I compiled it and then before actually trying to debug it I just executed(booted) the same binary with
bochs but it kept on restarting.

[bubach]

Why not just use Bochs internal debugger? Or at least use it to debug your debugger issues.

[vjain20]

I will try to use the internal debugger.Actually I tried remote debugging with qemu some time ago and it worked fine
so I went for remote debugging with bochs. Could you please tell how can I get the debug symbols file of my kernel for use with internal debugger ?

Thanks
Vaibhav

[bubach]

I have no idea, but fortunately I learned how to Google at an early age. I'll send you an invoice for my services later.

load-symbols [global] filename [offset]
Load symbols from file filename. If the global keyword is added, then the the symbols will be visible in all contexts for which symbols have not been loaded. Offset (default is 0) is added to every symbol entry. The symbols are loaded in the current (executing) context.

The symbol file consists of zero or more lines of the format "%x %s".