[OpenBIOS] [PATCH 2/2] Don't map the page 0 to make NULL-dereferencing more obvious

Mark Cave-Ayland mark.cave-ayland at ilande.co.uk
Tue Apr 9 21:27:09 CEST 2013

On 08/04/13 21:25, Artyom Tarasenko wrote:

>> You're probably calling ihandle>phandle with a phandle. I would expect the
>> return from active-package to be a phandle, not an ihandle.
> You are absolutely right. Removing ihandle>phandle helped.
> Thanks a lot!

Actually the fix is much easier than this:

Configuration device id QEMU version 1 machine id 32
CPUs: 1 x FMI,MB86904
UUID: 00000000-0000-0000-0000-000000000000
Welcome to OpenBIOS v1.0 built on Apr 9 2013 18:40
   Type 'help' for detailed information

0 > cd /chosen  ok
0 > .properties
name                      "chosen"
stdin                     ffce26f4
stdout                    ffce278c
memory                    ffce29c4
mmu                       0
screen                    ffce2610
0 >

According to the sample prtconf output, SPARC32 doesn't have an "mmu" 
chosen handle so we should just remove it. Now currently the property 
lives in forth/device/tree.fs so it exists across all architectures, 
however SPARC64 and PPC are fine because they create the property on 
demand during initialisation.

I've just committed a patch to fix this (on a second attempt as I 
accidentally caught the NULL dereference patch in there too) so please 
feel free to test.



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