[Qemu-devel] Re: [PATCH 0/5]

[Nathan Froyd]

On Sat, Jul 25, 2009 at 04:40:12PM +0800, Liu Yu wrote:
> For example booke has a code template for
> jumping to and returning from interrupt handlers:
>
>       bl transfer
>       .long handler_addr
>       .long ret_addr
>
> when call transfer, it never return but
> in transfer assembly code it will read the handler_addr
> and ultimately call the handler.
> Gdb doesn't know that and treat it as a normal function call.
> so gdb put a software breakpoint instruction at handler_addr,
> in order to get trap there when return from transfer.
>
> Then guest will read software breakpoint as handler_addr and jump to there..
>
> I'm not sure if x86 suffer this kind of issue.
> Is there any way to avoid this?

You would need to modify GDB to recognize this sort of case with the
skip_trampoline_code gdbarch method.

-Nathan