Re: Kernel compatibility between NetBSD/xen and NetBSD/i386 (or NetBSD/amd64)

[Matthias Scheler <tron%zhadum.org.uk@localhost>]

On Fri, Oct 16, 2009 at 07:33:12PM -0400, Thor Lancelot Simon wrote:
> > "uname -m" reports "i386" (respectively "amd64") under a NetBSD/xen kernel.
> > I think this is wrong because the two kernels are not ABI compatible
> > to none Xen kernels.
> 
> Sure they are -- for userspace code.

Yes, I know.

> I don't think uname -m is meant to describe the in-kernel ABI, but
> rather the ABI for userspace applications requesting services from
> the kernel.

That is "uname -p" as far as I know. All (or most?) of the NetBSD m68k
ports are userland compatible and report that this way. But their
kernels are not which they report via "uname -m":

        tron@serpens:~>uname -p
        m68k
        tron@serpens:~>uname -m
        amiga

> I think this change would break stuff.

The current values break stuff as well, in particular kernel modules.
Somebody on the #NetBSD IRC channel got a panic when he tried to
load a i386 LKM under NetBSD 5.0. I'm not sure what happens under
current with new style modules but they definitely don't work.

        Kind regards

-- 
Matthias Scheler                                  http://zhadum.org.uk/