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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 8 Mar 2018 17:23:29 +0100
Message-ID: <CAK8P3a3JpApY8hU1ROA3WbAM2FOO93kBxGpxVo=H6asvwoX84g@mail.gmail.com>
Subject: Re: RFC: remove the "tile" architecture from glibc
To:     John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc:     Helmut Grohne <helmut@subdivi.de>,
        GNU C Library <libc-alpha@sourceware.org>,
        linux-arch <linux-arch@vger.kernel.org>, metcalf@alum.mit.edu,
        Henrik Grindal Bakken <hgb@ifi.uio.no>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, Mar 8, 2018 at 5:06 PM, John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On 03/08/2018 04:55 PM, Arnd Bergmann wrote:
>>
>> I originally helped get tile, blackfin, metag, unicore32 and score into
>> the kernel, and it's always sad to see them go away after all the work
>> that was put into making them work. Out of the above, tile was
>> probably the best supported, and the most ambitious architecture
>> design, but in the end it seems it is just as dead as the others, so
>> I'll now add a patch to remove it along with the others in linux-4.17.
>
>
> Out of curiosity: Is there any reason why the removal of tilegx is now
> being rushed? Did any of the policies regarding architectures in the
> kernel change? I had the impression that architectures could previously
> stay unmaintained for a while before being removed.

No, nothing changed, we're normally just really bad at identifying
stuff that can go away exactly because that is the kind of thing
that nobody cares about any more.

I picked up the task to remove some of the stale architectures after
building a set of cross-compilers and noticing that some architectures
(score, unicore32, metag) are not supported by mainline gcc.

This has led me to a few more that I'm now removing after
making sure that nobody still wants them: m32r, frv, mn10300,
blackfin, cris and tile. I was planning to give some of these a
few more releases before removing them, but after talking with
the people that worked on them, the answer was always that
it's sad to let them go, but there is really no reason to keep
them.

I definitely hope that I did my research well, but if you can think
of any remaining users of upstream kernels that I missed, then
please let me know and I'll hold off on the removal for that
architecture.

The reason I want to do them all at once is that it takes a bit
of work to find all the architecture specific code in the kernel
outside of the arch/ directory, and removing nine architectures
at once makes that process much more efficient overall.

>> - sh3/sh4 looked like they would get revived a few years ago
>>    for the j-core project. The 2015 roadmap on
>>    http://j-core.org/roadmap.html had ambitious plans for
>>    an sh3 compatible core in 2017 and an sh4 compatible one
>>    in 2018. However, not much has happened  at all since 2016,
>>    and now the website is down as well. You might want to
>>    contact the j-core developers for clarification.
>>    I suspect this has also become a victim of the RISC-V
>>    success.
>
>
> Well, that's quite a bummer. I don't know what Rich Felker's and
> Rob Landley's plans now are. Rich told that he would be doing paid
> SH work again in the upcoming weeks. I even sent him and Rob SH4
> hardware to support their efforts.
>
> I have personally invested a lot of work into the SH port over the
> past three years in Debian and I was involved fixing many bugs
> and as a result, the port is quite usable. It would be really
> disappointing to see it being removed all of a sudden :(.
>
> I will get in touch with Rich and Rob to figure out what's going
> on.

Ok, thanks! I'd definitely like to know what's going on as well.

        Arnd