[Qemu-devel] Re: [PATCH 4/4] gdbstub: x86: Switch 64/32 bit registers dynamically

[Jan Kiszka]

Paul Brook wrote:
> On Saturday 27 June 2009, Jan Kiszka wrote:
>> Commit 56aebc891674cd2d07b3f64183415697be200084 changed gdbstub in way
>> that debugging 32 or 16-bit guest code is no longer possible with qemu
>> for x86_64 guest CPUs. Since that commit, qemu only provides registers
>> sets for 64-bit, forcing current and foreseeable gdb to also switch its
>> architecture to 64-bit. And this breaks if the inferior is 32 or 16 bit.
>>
>> No question, this is a gdb issue. But, as it was confirmed in several
>> discusssions with gdb people, it is a non-trivial thing to fix. So until
>> qemu finds a gdb version attach with a rework x86 support, we have to
>> work around it by switching the register layout as the guest switches
>> its execution mode between 16/32 and 64 bit.
> 
> I still object to this patch. Especially as there's no indication that it's a 
> harroble hack to workaround broken GDB.

Sorry, last sentence doesn't parse for me.

So what do you suggest for fixing this bug? Do you have a patch at hand
to fix gdb before 7.0? And a solution for older gdbs?

Jan

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