Re: [Qemu-devel] Cross-debugging support in QEMU using GDB

[Alexander Graf]

On 29.10.2009, at 17:26, Boyapati, Anitha wrote:

> Hello Alex,
>
> > > Essentially, what I am looking for is something like,
> > >         qemu-x -s <any_ELF_executable> [options]
> > >         targetx-gdb <any_ELF_executable>
> >
> > Yes. qemu-x -g 1234 <file> <options>
> > And then use gdb -ex 'target remote localhost:1234'.
> >
> > > where qemu-x is a user mode qemu for target X.
> > >
> > > More on (2): if there is no OS, then I think a small application
> > > like bootloader should probably be present to launch the cross-
> > > compiled executable on to Qemu. Any further suggestions on how to
> > > make (2) possible?  All the previous threads in developer mail
> > > archives dealt with debugging linux image in some form or the other.
> >
> > Qemu does that job, interpreting the ELF headers. I'm not sure where
> > the linking is done though, so maybe better read the code there :-).
> >
> > Just try out qemu-i386 for now! Try to run a statically linked i386
> > binary on a non-i386 platform, so you get the hang of it.
>
> Wow! I just got the gist of entire thing having done the same  
> successfully for i386. Actually I got confused at multiple points  
> purely because of my mistakes.
>
> As I am running the entire setup on virtual box, I don't have  
> bzImage. I continued my kernel debugging attempts with linux.img (me  
> in sleep mode :P). Then I ran an avr32 version of qemu which gave  
> some weird results (the patch Rabin gave has GDB support in its TODO  
> list and I overlooked it).Indeed the advice greatly helped to sort  
> out most of the issues :)

I'm glad it sorted things out.

> On the other hand, I think this can be documented in GDB usage  
> section of QEMU documentation.

Patches to documentation bits are always welcome! Certain developers  
(definitely me included) tend to forget that people actually read  
documentation ;-)

Alex