Subject: Re: port-i386/26007
To: None <gavan@netbsd.org, gnats-admin@netbsd.org, netbsd-bugs@netbsd.org>
From: Gavan Fantom <gavan@coolfactor.org>
List: netbsd-bugs
Date: 10/28/2005 18:55:01
The following reply was made to PR port-i386/26007; it has been noted by GNATS.

From: Gavan Fantom <gavan@coolfactor.org>
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: port-i386/26007
Date: Fri, 28 Oct 2005 19:54:32 +0100

 David Laight wrote:
 > The following reply was made to PR port-i386/26007; it has been noted by GNATS.
 > 
 > From: David Laight <david@l8s.co.uk>
 > To: gnats-bugs@netbsd.org
 > Cc: 
 > Subject: Re: port-i386/26007
 > Date: Fri, 28 Oct 2005 17:40:19 +0100
 > 
 >  On Fri, Oct 28, 2005 at 12:08:02PM +0000, Gavan Fantom wrote:
 >  >  
 >  >  I had speculated that this may be a CPU bug. I'm now starting to wonder 
 >  >  whether the BIOS is enabling more caches than we're expecting.
 >  
 >  One difference between the 1.6 bootcode and the current copy is that
 >  prot_to_real used to do an immediate ljmp having just written to the
 >  code to patch the instruction.  I changed it to do an indirect longjump.
 >  
 >  I don't think anyone has tried reverting that change.
 >  (Nor the other subtle changes required to get the correct address mode
 >  and bound bits set in the segment descriptor - IIRC especially SS)
 
 Does any other OS do it the way we currently do?
 
 -- 
 Gillette - the best a man can forget