[geeks] Solaris 9 changes

[Scott Howard]

On Wed, Jul 28, 2004 at 07:48:58AM -0500, Mike Hebel wrote:
> I'm confused by this.  The U1s run 64-bit - my Sol 7, yes I'm behind and I
> know it, is running in that mode.
> Or am I missing something blindingly obvious?

OK, see here's the thing...

There's a bug in the Ultra-SPARC I's.
When they are running in 64 bit mode there is a specific instruction
code which will stall the processor. Basically, lock it solid.

The specific instruction which does this is one which will never occur
naturally - it's only a problem if someone does it maliciously. The
specific instruction is NOT publically known, and is not even available
to Sun staff - it's very much a "need to know" thing.

But despite all this, running UltraSPAC I's in 64 bit mode was never
recommended. By default they boot to the 32 bit kernel, and you need to
make changes to a config file to allow 64 bit mode.

So having done this for years, to do a backflip and start defaulting to
64 bit mode for the US-1's (with the removal of the 32 bit kernel)
wasn't really an option.

The good news is that (as at a few builds ago at least) there was
nothing in S10 which won't work on an UltraSPARC-I with the exception of
the check on boot which stops it working. There are workarounds already
on the web to get around this, and I would expect that it won't be long
after the FCS release of 10 that someone comes out with a simple way
(probably a hex edit of a file of the like) to get around this...

  Scott.