64bit loader

[David O'Brien]

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.
 
-- 
-- David  (obrien at FreeBSD.org)