Re: Question on BIGGEST_ALIGNMENT in GCC on NetBSD/m68k

[Geert Uytterhoeven <geert%linux-m68k.org@localhost>]

Hi Laurent,

On Mon, 16 Jun 2025 at 11:16, Laurent Vivier <laurent%vivier.eu@localhost> wrote:
> Le 16/06/2025 à 11:00, John Paul Adrian Glaubitz a écrit :
> >> And there will be a problem with binfmt_misc because we can't rely on
> >> the ELF signature to know which qemu-user to run, the one with 2byte
> >> alignment or the one with 4byte alignment?
> > What about the ELF note [1] that David Brownlee suggested? Can these be used?
> >
> > Adrian
> >
> >> [1]https://www.netbsd.org/docs/kernel/elf-notes.html
>
> binfmt_misc doesn't use the sections to select the interpreter, but the
> 128 first bytes of the file.
>
> I think you need to change the ABI type in the ELF header:
> https://fr.wikipedia.org/wiki/Executable_and_Linkable_Format

Interesting....

Does any system actually use ABI (byte 7) = 3 (Linux)?
All of amd64/arm/arm64/ia64/i386/m68k/microblaze/mips(el)/powerpc/risvc/s390/sh/sparc
seem to use 0 (SYSV).

#define ELFOSABI_NONE   0
#define ELFOSABI_LINUX  3

Ah, parisc does. And C6x uses 0x40.

Gr{oetje,eeting}s,

                        Geert

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

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