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

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

On Sun, Oct 15, 2017 at 4:11 AM, Christian Gagneraud <chgans@gmail.com> wrote:
> On 14 October 2017 at 21:52, Hesham M <hesham.eembedded@gmail.com> wrote:
>> 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.
>
> Core dump are just ELF files, you might be able to create one yourself:
> https://stackoverflow.com/questions/5986366/elf-core-file-format
>
>
>>>
>>>>
>>>> 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.
>
> Do you have a link to this SO question?
>
> Chris

Hi Chris,

Thank for your reply. I know core is an elf file but it'd be helpful
if there is a tool that can help or something in gdb that I can use
instead of reinventing the wheel.
If this is the only resort, I might need to do it. If this can be
included somehow in GDB, provided nothing can do that now and there is
interest in this, I can try to help. I'd need community support,
though, as I haven't done any gdb work before.

My deleted SO question link:
https://stackoverflow.com/questions/46374391/postmortem-debugging-with-gdb-from-memory-dump-not-core

Thanks,
-Hesham