[RFC v7 00/21] Unifying LKL into UML

[Anton Ivanov]

On 08/10/2020 13:12, Hajime Tazaki wrote:
> Hello Anton,
>
> On Wed, 07 Oct 2020 22:30:03 +0900,
> Anton Ivanov wrote:
>>
>> On 06/10/2020 10:44, Hajime Tazaki wrote:
>>> This is another spin of the unification of LKL into UML.  Based on the
>>> discussion of v4 patchset, we have tried to address issue raised and
>>> rewrote the patchset from scratch.  The summary is listed in the
>>> changelog below.
>>>
>>> Although there are still bugs in the patchset, we'd like to ask your
>>> opinions on the design we changed.
>>>
>>> The milestone section is also updated: this patchset is for the
>>> milestone 1, though the common init API is still not implemented yet.
>>>
>>>
>>> Changes in rfc v7:
>>> - preserve `make ARCH=um` syntax to build UML
>>> - introduce `make ARCH=um UMMODE=library` to build library mode
>>> - fix undefined symbols issue during modpost
>>> - clean up makefiles (arch/um, tools/um)
>> Hi Hajime, hi Tavi,
>>
>> Our starting point should be that it does not break the existing build. It still does.
> I agree with the starting point.
>
>> If I build a "stock configuration" UML after applying the patchset
>> the resulting vmlinux is not executable.
> Ah, I confirmed the issue.
> I was only trying to make the `linux` binary compatible, not vmlinux.
>
> Because vmlinux is now build as a relocatable object, this is
> something we need to figure out if we wish to keep vmlinux executable.
>
> Do you think we should make vmlinux executable even if we have the
> file linux executable ? If yes, we will work on this to fix the issue.

In my opinion, any relocatable objects, etc should be clearly named - either .o, .so, etc depending on what they are. We should not try to reuse any of the existing files for a different purpose.

I also agree with Johannes that we are not using the tools/ directory for its intended purpose.

We are not trying to build a tool. We are trying to build a sub-architecture. IMHO, the build should use a subdirectory under arch/um.

>> On the positive side, it builds cleanly now. I will try to go
>> through the rest of the patchset later today and see if there is
>> anything else that needs fixing before we do the next version.
> thanks for your time.
>
> -- Hajime
>
>
-- 
Anton R. Ivanov
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