Re: Kernel Application Binary Interface (kABI) support in FreeBSD

Yes, my question was about kernel module compatibililty with FreeBSD's
major releases of a particular version.
For example, will FreeBSD makes sure that the driver built on 10.0 version
of Freebsd seamlessly load on all other 10.x versions of FreeBSD?
Does it make sure that the symbols and their parameters are not blindly
changed without considering the binary compatibility with other FreeBSD
version binaries?

RHEL kABI whitelist makes sure that once the symbol is added into the
whitelist, it will never be changed during the major releases of that
kernel.


Thanks,
Venkat.

On Fri, Jul 17, 2015 at 8:29 PM, Allan Jude <allanjude_at_freebsd.org> wrote:

> On 2015-07-17 10:47, Julian Elischer wrote:
> > On 7/17/15 9:02 PM, Venkat Duvvuru wrote:
> >> Hi,
> >>
> >> Is there kABI (Kabi-whitelist) equivalent feature in FreeBSD?
> > well, yes and no.
> >
> > Firstly, FreeBSD maintains a backwards compatible kABI (with the
> > exception of programs that hunt around in kernel memory).
> > We also use symbol versioning on the libc. so depending on what you want
> > to do. the answer may be useful to you or not.
> > Basically any binary should continue to run on a newer kernel, even if
> > the syscalls change, because we should still support the old abi.
> >
> > tell us more about what you need and we can be more specific.
> >
> > I have run Freebsd 1.1 binaries on a Freebsd 8  system, in fact I have
> > done a system build in a freebsd 1.1 chroot on an 8 system.
> > I haven't tried it on 9 or 10 but I'd expect it to work..
> >
> >
> >>
> >>
> >>
> >> Thanks,
> >>
> >> Venkat.
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>
> I think the question related to drivers (kernel modules).
>
> In which case, they should be compatible across major versions (module
> from 10.0 works in 10.2, but not 9.3 or 11.0)
>
> --
> Allan Jude
>
>