Re: [PATCH 3/4] gdb/lkd: Add Linux Kernel Awareness target

[Kieran Bingham <kieran dot bingham at linaro dot org>]

On 01/03/16 17:27, Yao Qi wrote:
> Kieran Bingham <kieran.bingham@linaro.org> writes:
> 
>> Provide infrastructure and thread awareness for the Linux Kernel
>> This functionality is heavily derived from the functionality created
>> by ST Microelectronics which provides a greater feature set.
> 
> In some file headers, there is such claimer
> 
> Copyright 2011-2013 STMicroelectronics.
> 
> the copyright should be associated to the FSF.  See other GDB source
> file headers.

Yes, of course - Sorry - I'll update these. My aim was to get the code
out to review the overall implementation.

> 
> Looks ST Microelectronics has already had signed copyright paper
> 
> GDB/INSIGHT	STMicroelectronics	2004-12-09
> Assigns past and future changes.

Excellent - I was worried about this :)

> 
>>
>> This specific implementation is stripped down to provide thread
>> awareness only. Other functionality that can already be provided by python
>> infrastructure such as information gathering tools specific to linux
>> have been submitted to the linux kernel project separately.
> 
> This patch includes too many things... could you split it so that the
> patch only include the very basic and simple kernel awareness feature.
> It may have bugs or may not handle some cases very well, but GDB can
> show the kernel threads.  The following patches can fix these bugs and
> do improvements.  For example, some commands added by this patch isn't
> necessary, nor the code for logging levels.  They can be split to
> separated patches.

Ok, I can go further in the chop.

At this level, I was hoping for a review of the method of implementation
through a target layer.

>>
>> Kernel module support is also already working and available through the
>> python extensions provided by the linux kernel and has been removed from
>> this submission.
> 
> I don't know how kernel module support is done through python
> extensions.  I thought linux kernel module can be handled as shared
> library under the solib infrastructure.  See files solib*.c.

The module list is parsed through a python command, which then searches
for the ko objects, and adds them to GDB as symbol files.

See:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/scripts/gdb/linux/modules.py

and in particular:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/scripts/gdb/linux/symbols.py


Regards

Kieran