Re: [PATCH] binfmt_flat: Remove shared library support

Geert Uytterhoeven
2022-04-21T06:54:23Z

On Thu, Apr 21, 2022 at 1:53 AM Greg Ungerer <gerg@linux-m68k.org> wrote:
> On 21/4/22 00:58, Eric W. Biederman wrote:
> > In a recent discussion[1] it was reported that the binfmt_flat library
> > support was only ever used on m68k and even on m68k has not been used
> > in a very long time.
> >
> > The structure of binfmt_flat is different from all of the other binfmt
> > implementations becasue of this shared library support and it made
> > life and code review more effort when I refactored the code in fs/exec.c.
> >
> > Since in practice the code is dead remove the binfmt_flat shared libarary
> > support and make maintenance of the code easier.
> >
> > [1] https://lkml.kernel.org/r/81788b56-5b15-7308-38c7-c7f2502c4e15@linux-m68k.org
> > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> > ---
> >
> > Can the binfmt_flat folks please verify that the shared library support
> > really isn't used?
>
> I can definitely confirm I don't use it on m68k. And I don't know of
> anyone that has used it in many years.
>
>
> > Was binfmt_flat being enabled on arm and sh the mistake it looks like?

I think the question was intended to be

Was *binfmt_flat_shared_flat* being enabled on arm and sh the
mistake it looks like?

> >
> > arch/arm/configs/lpc18xx_defconfig | 1 -
> > arch/arm/configs/mps2_defconfig | 1 -
> > arch/arm/configs/stm32_defconfig | 1 -
> > arch/arm/configs/vf610m4_defconfig | 1 -
>
> binfmt_flat works on ARM. I use it all the time.
> According to those defconfigs those are all non-MMU systems, so
> having binfmt_flat enabled makes some sense there.
>
>
> > arch/sh/configs/rsk7201_defconfig | 1 -
> > arch/sh/configs/rsk7203_defconfig | 1 -
> > arch/sh/configs/se7206_defconfig | 1 -
>
> Those are all SH2 systems if I am reading the defconfigs correctly.
> SH2 is non-MMU according to the Kconfig setup. So it makes sense that
> binfmt_flat is enabled on those too.

I've checked git history, and CONFIG_BINFMT_SHARED_FLAT was enabled
in se7206_defconfig in a non-specific defconfig update, so no
further info.
The other two had it enabled since their introduction, so I guess
they were just based on the former.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds