Re: [PATCH] binfmt_flat: Remove shared library support

Rich Felker
2022-04-20T20:23:32Z

On Wed, Apr 20, 2022 at 10:04:32PM +0200, Arnd Bergmann wrote:
> On Wed, Apr 20, 2022 at 7:47 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Yeah, I was trying to understand why systems were using binfmt_flat and
> > not binfmt_elf, given the mention of elf2flat -- is there really such a
> > large kernel memory footprint savings to be had from removing
> > binfmt_elf?
>
> I think the main reason for using flat binaries is nommu support on
> m68k, xtensa and risc-v. The regular binfmt_elf support requires
> an MMU, and the elf-fdpic variant is only available for arm and sh
> at this point (the other nommu architectures got removed over time).

I believe I made the elf-fdpic loader so that it's capable of loading
normal non-fdpic elf files on nommu (1bde925d23), unless somebody
broke that. I also seem to recall that capability being added to the
main elf loader later.

Rich