Subject: Re: 32/64bit -- Re: Ultra5?
To: Toru Nishimura <nisimura@itc.aist-nara.ac.jp>
From: Eduardo E. Horvath <eeh@one-o.com>
List: port-sparc64
Date: 03/12/2000 18:02:07
Whoah!  Someone else!

> I'm new to port-sparc64, and have little knowledge of past progress of
> NetBSD/sparc64.
> 
> > But remember the most important rule: do not mix 32-bit and 64-bit
> > kernels and userlands.  A 64-bit kernel may limp along for a short
> > time on a 32-bit userland before it dies, but a 32-bit kernel will
> > immediately fail on a 64-bit userland.
> 
> What's the issue in NetBSD/sparc64 of 32bit userland support by 64bit
> kernel?   Is it a technical difficulty or lack of imformation?

It's a technical problem.  You need to run with COMPAT_NETBSD32 to
have it work at all.  There are some system calls (mostly sysv IPC and
sysctl) that must be completely reimplemented in COMPAT_NETBSD32.

Then there are a suprizing number of programs that are kernel memory
grovellers, like ps.  How is a 32-bit application going to map in and
make any sense of 64-bit kernel datastructures?  I don't know.  Want
to work on it?

=========================================================================
Eduardo Horvath				eeh@netbsd.org
	"I need to find a pithy new quote." -- me