Re: Postmortem debugging with arm-none-eabi-gdb from memory dump (not core)

[Hesham M <hesham dot eembedded at gmail dot com>]

On Fri, Oct 13, 2017 at 4:19 PM, Yao Qi <qiyaoltc@gmail.com> wrote:
> On 17-10-05 05:55:38, Hesham M wrote:
>> Hi all,
>>
>> As this is my first email to the list, and as an old user for gdb, I'd like
>> first to thank the gdb community for their effort.
>>
>> In a bare-metal ARM system, is there a way to use arm-none-eabi-gdb for
>> postmortem debugging, the same way we do when we debug with core file on
>> Linux, for example?
>>
>> The issue is that I don't have a "core" file but I can generate memory dump
>> of the whole memory (ROM is already known and through the hardware debugger
>> used I can write the RAM contents to a file (outside the target of course).
>> I can also collect the registers at the time of the crash. I can do the
>> debugging/analysis if I connect gdb to the target at the time of the crash
>> but I need to do this in later time away from the target. I hope to find a
>> way to debug with memory dumps the same way gdb debugs with core files.
>>
>> Of course if I can convert the memory dump to a valid core file, it might
>> be another path to the solution. I don't know how to do that or if there is
>> a tool that can help with this conversion.
>>
>> Any idea if this is possible?
>
> I prefer this approach, and it is possible.  GDB has a command "gcore",
> https://sourceware.org/gdb/current/onlinedocs/gdb/Core-File-Generation.html#index-generate_002dcore_002dfile
> you can take a loop how GDB does it.
>
>>
>> A variant of this is idea is done for Keil tools:
>> https://os.mbed.com/blog/entry/Post-mortem-debugging-with-ARM-mbed/
>>
>> I have posted a similar question on stackoverflow but they closed it! So,
>> please let me know if my question isn't clear.
>>
>> Thanks,
>> -Hesham
>
> --
> Yao (齐尧)


Hi Yao,

Thanks for replying. Unfortunately, gcore is not implemented for
bare-metal ARM, arm-none-eabi-gdb.
GDB documentation says abour gcore:

Note that this command is implemented only for some systems (as of
this writing, GNU/Linux, FreeBSD, Solaris, and S390).


Trying it on my system, I got:

(gdb) gcore file
Command not implemented for this target.

I appreciate any ideas or hints.

Thanks,
-Hesham