Re: PowerBook 5xx instability fix.

[Martin Husemann <martin%duskware.de@localhost>]

On Sun, Oct 27, 2024 at 08:12:26AM +1100, Nathanial Sloss wrote:
> Hi,
> 
> I've found that the PowerBook 5xx would crash randomly in pmap functions.  It 
> seems as though PTEs were referenced beyond the end of ram.
> 
> Unless there is a better way to handle this I'd like to commit the attached 
> patch.
> 
> I found the fix while limiting the available ram in the Booter.  Making the ram 
> smaller in the Booter the PowerBook never crashed.  But to lose 1MB ram is 
> wasteful so with the patch at least I only lose 48k.

What mmu_type does that machine have?

Can you add debug code to dump the generated PTEs during pmap_bootstrap
(or can ddb show them? If not we probably should add a mach command to
do that)

Could this be some bug in the msgbuf setup (machdep.c lines 294ff) ?

Martin