Re: [PATCH 0/8] remove unicore32 support

[Arnd Bergmann <arnd@arndb.de>]

On Tue, Jun 23, 2020 at 8:57 AM Mike Rapoport <rppt@kernel.org> wrote:
>
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> The unicore32 port do not seem maintained for a long time now, there is no
> upstream toolchain that can create unicore32 binaries and all the links to
> prebuilt toolchains for unicore32 are dead. Even compilers that were
> available are not supported by the kernel anymore.

Peter Maydell also brought this up recently, since there is also a stale
qemu port.

I agree in principle that this port is about as dead as it gets and presumably
nobody has attempted running a kernel later than linux-4.9 nor will they
do that in the future. I see that the hardware support was never fully completed
either, with at least the "PKUnity-v3-UMAL" ethernet driver getting submitted
in 2011 but never merged and no public information on a driver for the
"PKUnity-v3-MMC" device that presumably holds the rootfs and the
"PKUnity-v3-UART" device.

However, it's worth pointing out two arguments against removal:

- Guan Xuetao is still listed as maintainer and asked for the port to be
   kept around the last time I suggested removing it two years ago.
   He promised that there would be compiler sources (llvm I think), but
   has not made those available since.

- https://github.com/gxt has patches to linux-4.9 and qemu-2.7, both
  released in 2016, with patches dated early 2019. These patches mainly
  restore a syscall ABI that was never part of mainline Linux but apparently
  used in production. qemu-2.8 removed support for that ABI and
  newer kernels (4.19+) as you say can no longer be built with the old
  toolchain, so I would guess there will not be any future updates to that
  git tree.

With that information added to the pull request and the maintainer
added to Cc:

Acked-by: Arnd Bergmann <arnd@arndb.de>