[rescue] Ultra1 OBP firmware message on installation boot

[Sid Odgers]

Yeah, just checked on groups.google -> seems very similar to the
F00F bug in concept, if not in implementation.  Wonder if a similar
workaround would be feasible....

With this in mind, the other thing the original poster would do well
to keep in mind is that from a DoS perspective, this all of a sudden
makes sandboxes and running services as non-root users more or less
irrelevant - if somebody wants to drop your box, and gets ANY access
at all, it's all over...

This happened to me once, incidentally, on an old P133 system through
one of the old BIND holes - BIND was running in a chroot sandbox as
an unprivileged user, and when the kids who cracked me figured out
they couldn't  actually DO anything, they crashed the box with the F00F
code.

Fun for all.

On Thu, Feb 13, 2003 at 04:00:17AM -0500, Curtis H. Wilbar Jr. wrote:
> As I recall it has something to do with the Ultra 1 processor when executing
> a particular sequence of 64 bit instructions.  It is more related to the
> hardware than the software.  Software wise as I recall that sequence would
> never really occur.... but if you specifically make an assembly program to
> make it occur, there is no realy way to protect against it (except run
> the kernel in 32 bit not 64).
> 
> Wish I could give you a URL to more data, but I'd have to go searching
> and I'd imagine this shouldn't be too hard to find in google... try
> "Ultra 1" +"64 bit" +"32 bit", and possibly +"bug" +"halt", etc...
> 
> -- Curt
> 
> >Date: Thu, 13 Feb 2003 20:00:22 +1100
> >From: Sid Odgers <sunrescue at dysphoria.eu.org>
> >To: "Curtis H. Wilbar Jr." <rescue at hawkmountain.net>, The Rescue List 
> <rescue at sunhelp.org>
> >Subject: Re: [rescue] Ultra1 OBP firmware message on installation boot
> >User-Agent: Mutt/1.4i
> >
> >Is this problem similar to the intel F0/0F and cyrix 'Coma' bug from
> >a few years back?  Or is it a Solaris bug?  I hadn't heard anything
> >about it, and I've got a few multi-user Ultra1s running NetBSD/64.
> >
> >On Thu, Feb 13, 2003 at 03:50:03AM -0500, Curtis H. Wilbar Jr. wrote:
> >> Keep in mind there is an issue on Ultra-1 machines in 64 bit mode
> >> where a userland assembly language program can do something bad
> >> to the machine (I think it can halt the cpu).  This problem is
> >> not present when running in 32 bit mode.
> >> 
> >> This is documented out there on the web somewhere.  If users will not
> >> be allowed logins to the box (i.e. a web server only allowing http and
> >> maybe ftp) then that won't be a problem.
> >> 
> >> -- Curt
> >> 
> >> >Date: Thu, 13 Feb 2003 19:48:01 +1100
> >> >From: Sid Odgers <sunrescue at dysphoria.eu.org>
> >> >To: patrick at zill.net, The Rescue List <rescue at sunhelp.org>
> >> >Subject: Re: [rescue] Ultra1 OBP firmware message on installation boot
> >> >User-Agent: Mutt/1.4i
> >> >
> >> >Yea,
> >> >
> >> >In terms of performance, unless you're doing heavily memory bound
> >> >jobs (ie processes which require more than 4GB of VM) or compute
> >> >jobs which use 64 bit integers or floats, you'd be hard pressed
> >> >to notice the difference.  If you ARE, then 64 bit computation
> >> >will be orders of magnitude faster (1 64-bit instruction takes
> >> >the place of 3 or 4 32-bit instructions which emulate the
> >> >64-bit instructions for long double(?) and long long types),
> >> >and large datasets will be unusable as a 64-bit memory pointer
> >> >is required to use more than 4GB of VM on flat architectures (
> >> >and it's usually not worth the performance hit on segmented
> >> >architectures like the newer IA32 stuff which, from memory,
> >> >has a 4 bit segment offset pointer in the LDT, allowing you
> >> >to address more than 4GB of VM in 4GB chunks)
> >> >
> >> >Nonetheless, 64-bit mode is 'cooler', and the (minimal) performance
> >> >hit you take for running 64 bit code instead of 32 bit code isn't
> >> >going to be noticable either way on a 1/170. :)
> >> >
> >> >On Thu, Feb 13, 2003 at 02:25:53AM -0500, Patrick Giagnocavo +1.717.201.3366 
> >> wrote:
> >> >> I am loading Solaris 9 on an Ultra1/170 with OBP 3.5 .
> >> >> 
> >> >> On boot, the installer gives a message about using the 32bit OS
> >> >> instead of 64bit OS.
> >> >> 
> >> >> I googled and found out how to change it, but my question is, is there
> >> >> a performance difference between the 2 kernels?  
> >> >> 
> >> >> I will be doing some PostgreSQL and web serving and some Perl (spit).
> >> >> 
> >> >> --Patrick
> >> >> _______________________________________________
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