Re: [Qemu-devel] Re: gdbstub: packet reply is too long

[Paul Brook <paul@codesourcery.com>]

> Do those archs also have multiple register layouts that are coupled to
> those different instruction sets? Do they switch the instruction sets
> via 'set arch'?

No, but neither does x86. You just need to teach gdb how to debug 32-bit code 
on a 64-bit target.

> I think x86 is (historically) special here.

I think it's just that noone's made the effort to fix this problem.

> Fixing this (once understood what are all the problems preventing a fix
> for several years now) is one thing, keeping the workaround for current
> gdb in qemu is, IMHO, another. Right now we don't have a gdb fix in
> sight, so I'm simply voting for reintroducing the workaround. That's
> all. We can kill it or make it optional once the issue is solved. But we
> should _not_ do this _before_ it is solved, causing only pain to people
> who just want to use the gdbstub.

I don't buy this argument. You already have to tell gdb which mode to work in, 
so I don't see any reason why you shouldn't also tell qemu.

Recent GDB interrogate the target when they connect, and the target describes 
the registers it has. This isn't currently implemented on x86 in qemu, but 
I'm pretty sure it'd be incompatible with dynamic switching.

Paul