Re: [LTP] Call for nommu LTP maintainer [was: Re: [PATCH 00/36] Remove UCLINUX from LTP]

Greg Ungerer
2024-01-10T15:19:11Z

On 10/1/24 06:24, Rob Landley wrote:
> On 1/8/24 03:03, Petr Vorel wrote:
>> Hi Rob, all,
>>
>> [ Added Niklas Cassel, who is maintainer of qemu_riscv64_nommu_virt_defconfig in
>> buildroot ]
>
> Hi Niklas!
>
>>> Buildroot also apparently has an LTP package selectable in menuconfig:
>>
>>> https://github.com/buildroot/buildroot/tree/master/package/ltp-testsuite
>>
>>> But I haven't tried it...
>>
>> I'm the maintainer of the LTP package in buildroot in my private time.
>> BTW I spent quite a lot of time fixing LTP (and some other system packages,
>> e.g. nfs-utils) compilation on some old legacy architectures reported via
>> http://autobuild.buildroot.net/ I've never used in the reality.
>> But I certainly don't have time to drive nommu support in my private time.
>> I don't even have an interest, I don't use any nommu device.
>
> I do, but I've never done much with LTP, and I have my hands full with toybox
> and mkroot already.
>
>> Therefore nobody who is not involved in nommu will not find a time to support it
>> in LTP (support does not mean just to add the functionality to the new C API,
>> but run tests on nommu and fix failing bugs). I suppose nobody is paid to work
>> on nommu platforms, it would have to be a hobby project, right?
>
> A bunch of people are paid to work on nommu platforms, and I've worked with them
> a bunch, but none of them talk to linux-kernel. They find the culture toxic,
> insular, and categorically dismissive of their interests.

I have been involved in the kernel nommu space for 20 years, and sure, there is
some of that. But mostly spending some time and effort to get involved pays off.
I have seen potential contributors show up with some arrogant attitudes too,
so it cuts both ways here.

The m68k community I have been part of has been nothing but welcoming. The mm
people have tried hard to keep nommu support up-to-date where almost none of them
actually have a vested interest in doing so.

What I have seen is that many companies working in this space just don't want
to spend the time and effort to go mainline. That is a business decision they
make, and that is fine. Heck my work in actual mainline has never really been
paid for by any company and I have sunk a _lot_ of time into it. (Full disclosure
I did get paid to work on early porting and support - just not geting it into
mainline and maintain it there).

> For example, cortex-m is a large nommu platform on which vendors support Linux
> BSPs, but notice how page 8 of
> https://www.microsemi.com/document-portal/doc_view/132181-linux-cortex-m-users-manual
> points at a cross compiler toolchain from _2010_ and page 4 says they're booting
> a 2.6.33 kernel?

Any company/person who follows the route of not working with the linux kernel
community to get their work included is going to inevitably get stuck on older
versions of everything.

> I'm a bit weird in that I try to get CURRENT stuff to work on nommu, and a lot
> of people have been happy to consume my work, but getting any of them to post
> directly to linux-kernel is like pulling teeth.

I regularly test nommu configurations (as in every kernel rc and release) on m68k
and at least every release on other architectures like arm(*) and recently on
riscv as well.

(*) somewhat annoyingly needing a minor patch to run the versatile qemu platform
I like to test with. But hey, that is on me :-)

Regards
Greg

>> But as I said, if anybody from nommu decides to maintain it in LTP, I'll try to
>> support him in my free time (review patches, give advices). And if nobody
>> stands, this patchset which removes the support in the old API will be merged
>> after next LTP release (in the end of January).
>
> What does the API migration do? Is there a page on it ala OABI vs EABI in arm or
> something?
>
> Rob