On Tue, 31 May 2005 23:22:11 -0700
Chuck Silvers <chuq@chuq.com> wrote:

[D390]
> > Is this a big task to add that support?=20
> different TLB handling,
Yes, obviously. As I understand it (my knowldege in the VM area is very
limited) PA-2.0 TLBs / MMU are a "linear extension" from 32 bit to 64
bit. It is possible to run code in a 32 bit space on a PA-2.0 CPU so
that the code still sees a PA-1.1 environment.

> different busses.
To simplify: There are two generations of PA-2.0 machines: The early
machines with GSC bus (and optional PCI) and those with PCI only. The
early machines are quite similar to already supported machines. I
suspect that we can support things like the D390, C240, C360, ... very
fast once the TLB / pmap(9) stuff is done. The newer PCI only machines
will need support for the newer PCI host bridges. This shouldn't be
hard. I already have a C240 (old with GSC) and a B2000 (new PCI only)
PA-2.0 machines to work on. Unfortunately I am no VM guru, so I have to
leave this exercise to someone else.

> that model at least has firmware that can run in 32-bit mode,
> so we won't need a 64-bit kernel to make it go.  at least,
> I remember running 32-bit hpux on one some years back.
I talked to a HP-PA Linux developer last year at the LinuxTag. He toled
me that most PA-2.0 machines support 32 firmware / kernel. Only a few
"server machines" are 64 bit only.

> but it'll be a fair bit of work.
OpenBSD (mickey@) has done it. Maybe we can get some code from there?
--=20


tsch=FC=DF,
       Jochen

Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/