[OpenBIOS] Booting SunOS from OpenBIOS

Artyom Tarasenko atar4qemu at gmail.com
Sun Apr 7 22:10:14 CEST 2013

On Sun, Apr 7, 2013 at 8:30 PM, Mark Cave-Ayland
<mark.cave-ayland at ilande.co.uk> wrote:
> On 06/04/13 20:34, Artyom Tarasenko wrote:
>> Unfortunately not:
> Hmmm so a quick look at the Linux source code (and some dumps from QEMU's
> "info tlb") showed me what has happening here. The problem is that Linux
> doesn't read the value of the "translations" property from OpenBIOS when
> taking over the MMU page table - instead it performs a manual scan of the
> existing page table between a range of addresses.
> It looks as if the range is from 0xfe400000 to 0xfff00000, however the lower
> ends of these ranges seem to be repurposed for debuggers and I/O memory - so
> it means that if we keep anything too far outside of the PROM range
> 0xffd00000 to 0xfff00000 then we're going to be in trouble.
> Unfortunately because we map the entire framebuffer directly then we don't
> have much memory to play with :(  I think the only solution is to reduce the
> amount of memory for the Forth machine for SPARC32 by changing MEMORY_SIZE
> in arch/sparc32/openbios.c, and then tucking it underneath 0xffd00000 as per
> my last patchset.
> So far I can get away with reducing it to 128K, and Bob's original test case
> for increasing the Forth machine memory (because of lack of memory for the
> Fcode table) still runs, e.g.
> fd000000 1000 l!
> 00000020 1004 l!
> 12095145 1008 l!
> 4d552c74 100c l!
> 65737401 1010 l!
> 1412046e 1014 l!
> 616d6501 1018 l!
> 10000000 101c l!
> cd /iommu/sbus
> " /iommu/sbus" select-dev
> new-device
> 1000 1 byte-load
> Artyom - can you confirm whether reducing MEMORY_SIZE to 128K is enough for
> kadb to work in your SunOS image? If that works, I'll create another patch
> series for you to test.

You mean, instead of modifying ofmem_arch_get_virt_top, right?
Yes, this seems to be enough, kadb starts.

Artyom Tarasenko

linux/sparc and solaris/sparc under qemu blog:

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