Re: NetBSD/virt68k live-image

Izumi Tsutsui <[email protected]> Sat, 8 Feb 2025 22:05:18 +0900
Newsgroups gmane.os.netbsd.ports.m68k
Message-ID <[email protected]>
> >[  79.7500030] panic: enter: out of address space
> 
> 
> Yes, I noticed when Jason created virt68k. Amiga also uses pmap_motorola,
> there must be another difference.

Really? How does amiga handle it?

IIUC, hp300 pmap for 040 uses just one page to store both
L1 and L2 tables, so each process can use only upto 15 L2 tables
(1 is used for L1), then 
 128 (L2 entries) * 15 (num of L2) * 32 (L3 entries) * 8192 (bytes/page)
 = 480MB
is an upper limit of the historical pmap design, i.e. we cannot bump
MAXUL2SIZE unless we can allocate physically  contiguous pages for
the L2 tables.

IIRC mhitch@ had an idea to hack MI pmap_motorola.c to solve it, though.

---
Izumi Tsutsui