Re: COMPAT_FREEBSD<ancient>

On Tue, Sep 16, 2025 at 3:07 PM Konstantin Belousov <kostikbel@gmail.com> wrote:
> On Tue, Sep 16, 2025 at 08:36:11AM -0400, Josef 'Jeff' Sipek wrote:
> > Greetings,
> >
> > A couple of months ago I was looking through some random kernel code and I
> > noticed COMPAT_FREEBSD4 and friends.  I was curious how much code was behind
> > those so I whipped up a couple of quick and dirty patches to remove
> > COMPAT_FREEBSD4 and COMPAT_43.  The answer is about 1300 and 1800 loc,
> > respectively.
> >
> > Which brings up a question - at what point does it make sense to remove some
> > of this code?
> Never.

+1 :-)


> > IIUC, this code falls well outside the current policy around
> > ABI compatibility.
> How so?
>
> > So the only thing that the removal of these compat
> > layers should affect is source compatibility, but since this compat code is
> You do not understand what ABI compat is.
>
> > about syscalls (at least according to sys/conf/NOTES) any code still using
> > these interfaces would have to explicitly invoke these compat syscalls and
> > not their new replacements.  IOW, this should be a vanishingly small number
> > of programs.  (As an additional data point, on amd64 GENERIC defines all of
> > them but MINIMAL starts with COMPAT_FREEBSD10.)
>
> We do run FreeBSD 1.0 binaries on HEAD, with the right config.  I do not see
> a reason to break this.

+1 :-)

> > I'm happy to clean up my diffs and get them into 16.0-CURRENT if there is
> > interest.
> I am not happy.

Looks like there is no interest and will be no interest in the FreeBSD
world to break backward compatibility for any reason :-)

-- 
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info