> (Note I'm not a MIPS guy, so maybe I'm wrong...)
>
>> If it works for you, I will commit the changes -- Nishimura-san may 
>> bitch,
>> but he hasn't come up with better code;
>
> Well, I guess Nishimura-san's goal is to replace current mips pmap
> completely, so it will take loooong time and he won't _patch_
> current (broken?) pmap ;-)
>
> I think the "real fix" is not easy, but the problem is simple,
> virtual alias, isn't it?
>
> Current pmap_zero_page() and pmap_copy_page() uses KSEG0
> but zeroed or copied pages are accessed via KSEG2 later,
> so these functions generate a bunch of virtual aliases.
> The ugly (but simple) workaround is to flush cache for such KSEG0
> pages, but current pmap_zero_page() and pmap_copy_page() do it
> only if (MIPS_HAS_R4K_MMU && mips_sdcache_line_size == 0),
> which is not correct.
>
> The intention of checking L2cache size there is to check
> if virtual alias will be handled by virtual coherency exceptions
> (that is supported by R4000/R4400 CPUs with L2 cache)
> but R4600/R4700/R5000 don't have any hardware support for VCE
> even with L2 cache.
>
> The better (but not the best, of cource ;-p) fix is to prepare
> some variable in mips/cache.c which indicates if virtual aliases
> will be handled by hardware or not and use it instead of
> current mips_sdcache_line_size. The simple check is
> "the machine has R4000/R4400 with L2cache or R10000,"
> but in the perfect world, maybe we should also check
> which CPU has virtual-indexed-physically-tagged cache
> and L1 cache size is larger than pagesize.
>
> On the other hand, current VCE handlers flush L2 cache anyway
> and cpu_lwp_fork() in mips/vm_machdep.c have to flush cache
> to avold virtual alias in kernel stack created by
> pmap_zero_page() even on R4000 with L2, so I think
> it's better to flush cache the KSEG0 page unconditionally
> at least in pmap_zero_page()...
>
> I guess pmap_pv_page_alloc() has the same problem
> since it uses KSEG0. mips/mem.c also allows to access
> any KVA via KSEG0.

to make it really short:

i do have a Power Indigo2 (with MIPS R8000 :) and would *really* like 
it to run NetBSD. AFAIK the IP26 (I2/R8k) is not yet supported (maybe 
that nobody tried it, tho)...

is there anything i could do (try to set it up, making it reachable via 
serial line)?

-- 
mit vorzueglichster Hochachtung/best regards,

Timo Schoeler
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