64bit loader

[Peter Wemm]

On Thursday 02 June 2005 01:29 am, David O'Brien wrote:
> On Wed, Jun 01, 2005 at 10:09:47AM -0700, Peter Wemm wrote:
> > Yes, there are a lot of good reasons to do it the way it is done,
> > but this is the killer reason.  We simply cannot do vm86 or bios
> > calls from a 64 bit loader, period.
> >
> > Other "good" reasons, besides the above:
> > * We don't need to maintain a seperate loader code base
> > * We can load test kernels with an existing loader on a
> > FreeBSD/i386 system (and run from a ramdisk or miniroot)
> > * We would need to maintain 32 bit code to do bios calls anyway,
> > even if we did switch between 32 bit and 64 bit mode on the fly. 
> > If we have a complete 32 bit BTX environment, we get massive
> > complexity for little benefit.
>
> I personally am very happy with the way we handle switching into long
> mode and loading 64-bit kernels today. :-)  I think the current
> advantages list > disadvantages list.

BTW: I especially like sys/amd64/amd64/locore.s versus 
sys/i386/i386/locore.s

-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5