Re: Question on BIGGEST_ALIGNMENT in GCC on NetBSD/m68k

Hi Jason,

On Mon, 2025-06-16 at 07:43 -0700, Jason Thorpe wrote:
> > On Jun 16, 2025, at 2:10=E2=80=AFAM, Laurent Vivier <[email protected]>=
 wrote:
> >=20
> > I think you need to change the ABI type in the ELF header:
> > https://fr.wikipedia.org/wiki/Executable_and_Linkable_Format
>=20
> 4-byte alignment binaries should have ELFOSABI_SYSV (0) (since that ABI s=
pec
> is where the 4 byte alignment comes from).  If Linux/m68k is already usin=
g that,
> then those binaries are broken by definition.

Unfortunately, that's exactly the case:

root@mitchy:~# uname -a
Linux mitchy 6.15.0-rc2-virt #1 Thu May  1 10:27:28 UTC 2025 m68k GNU/Linux
root@mitchy:~# readelf -h /bin/bash |grep "OS/ABI"
  OS/ABI:                            UNIX - System V
root@mitchy:~#

> Let=E2=80=99s hope existing Linux/m68k binaries are using ELFOSABI_LINUX =
/ ELFOSABI_GNU (3)
> (sorry, I don=E2=80=99t have any handy to check).

hppa is using it:

glaubitz@panama:~$=20
glaubitz@panama:~$ uname -a
Linux panama 6.12.32-parisc64 #1 SMP Debian 6.12.32-1 (2025-06-07) parisc64=
 GNU/Linux
glaubitz@panama:~$ readelf -h /bin/bash|grep "OS/ABI"
  OS/ABI:                            UNIX - GNU
glaubitz@panama:~$

> If the existing binaries correctly label themselves has having the Linux-=
specific ABI,
> then this is trivial and there=E2=80=99s no reason to use a note to diffe=
rentiate them.

I don't have a strong preference as both of them are used in the Linux kern=
el.

Adrian

--=20
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913