Re: Bug in i386_process_record?

[Hui Zhu <teawater at gmail dot com>]

On Thu, Aug 27, 2009 at 08:28, Michael Snyder<msnyder@vmware.com> wrote:
> Michael Snyder wrote:
>>
>> Hui Zhu wrote:
>>>
>>> On Wed, Aug 26, 2009 at 02:42, Eli Zaretskii<eliz@gnu.org> wrote:
>>>>>
>>>>> From: Hui Zhu <teawater@gmail.com>
>>>>> Date: Tue, 25 Aug 2009 13:02:44 +0800
>>>>> Cc: msnyder@vmware.com, gdb-patches@sourceware.org
>>>>>
>>>>> It seems that the segment (It is not the section) ?registers in x86
>>>>> protect mode is just help MMU to get the physical address. ?It's
>>>>> transparent for the user level program.
>>>>
>>>> It's transparent if $es and $ds have the same value (which they
>>>> usually do, AFAIK).
>>>>
>>>>> What do you think about remove this warning from this patch?
>>>>
>>>> I would indeed do that, if we find that $es and $ds have the same
>>>> values. ?Assuming that someone who knows Linux better than I do
>>>> confirms that these two registers hold the same selector when a normal
>>>> application is running in user mode.
>>>>
>>> Thanks for remind me. ?We cannot get the value of each segment
>>> register, but we can get each segment register point to. ?So if the
>>> value of segment registers, it's means that the value of them is same.
>>>
>>> I add some code about it:
>>> ? ? ? ? ?regcache_raw_read_unsigned (ir.regcache,
>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?ir.regmap[X86_RECORD_ES_REGNUM],
>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?&es);
>>> ? ? ? ? ?regcache_raw_read_unsigned (ir.regcache,
>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?ir.regmap[X86_RECORD_DS_REGNUM],
>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?&ds);
>>> ? ? ? ? ?if (ir.aflag && (es != ds))
>>> ? ? ? ? ? ?{
>>>
>>> After that, we will not get the warning because the es is same with ds
>>> in user level.
>>>
>>> What do you think about it?
>>
>> I think it is the best version I have seen so far.
>> And it seems to follow the conclusions of the discussion.
>> And I've tested it, and it seems to work.
>>
>> I would say wait until end-of-business Friday, and
>> if there are no more comments, check it in!
>
> Hui,
>
> Do you think you could add some new tests to i386-reverse.exp,
> to verify the string instructions?
>
> Thanks,
> Michael
>

OK. I will do it.

Thanks,
Hui