Re: [OpenBIOS] QEMU OpenBIOS booting?

[Laurent Vivier]

Le dimanche 19 avril 2009 à 13:14 -0700, Steven Noonan a écrit :
> On Sun, Apr 19, 2009 at 1:08 PM, Laurent Vivier  wrote:
> > Le dimanche 19 avril 2009 à 13:00 -0700, Steven Noonan a écrit :
> > > On Sun, Apr 19, 2009 at 12:23 PM, Blue Swirl  wrote:
> > > > On 4/19/09, Steven Noonan  wrote:
> > > > > On Sun, Apr 19, 2009 at 1:24 AM, Laurent Vivier  wrote:
> > > > > > Le dimanche 19 avril 2009 à 00:50 -0700, Steven Noonan a écrit :
> > > > > > > On Tue, Apr 14, 2009 at 10:46 PM, Steven Noonan  wrote:
> > > > > > > > On Sun, Apr 12, 2009 at 1:39 AM, Laurent Vivier  wrote:
> > > > > > > >> OpenBIOS is not able to boot MacOS X.
> > > > > > > >
> > >
> > > [...]
> > > $=:>> XCOFF - load_xcoff: Loading 'System\Library\CoreServices\BootX'
> > > > > XCOFF - load_xcoff: XCOFF file with 3 sections entry:fff0a22c
> > > > > XCOFF - load_xcoff: Read next header (5c)
> > > > > XCOFF - load_xcoff: Load '.text' section from 5c d4 to 5600000 (28000)
> > > > > XCOFF - load_xcoff: Read next header (84)
> > > > > XCOFF - load_xcoff: Load '.data' section from 84 280d4 to 5628000 (2000)
> > > > > XCOFF - load_xcoff: Read next header (ac)
> > > > > XCOFF - load_xcoff: Erase '.bss' section at 562a000 size: 3a000
> > > > > ELF - transfer_control_to_elf: Starting ELF boot loader
> > >
> > > invalid/unsupported opcode: 02 - 0e - 0c (0b717b1c) 05616ed8 1
> > > invalid/unsupported opcode: 00 - 14 - 13 (000064e8) 000094d0 0
> > > Alcarin:qemu steven$
> > >
> > > So at least with my patches, we're getting what people with QEMU 0.8.0
> > > were getting: http://tinyurl.com/qemu080
> > >
> > > So now what's left is resolving -why- that 'invalid/unsupported
> > > opcode' issue crops up.
> >
> > I think the booloader is loaded at addresses overwriting some parts of
> > openbios.
>
> That would make sense, but that tells me QEMU is loading OpenBIOS to

The problem is in OpenBios: I put some structures in memory without
knowing this... but this is not part of openfirmware specification.
> the wrong location. From the book "Mac OS X Internals: A Systems
> Approach":
>
> Table 45. BootX Logical Memory Map
>
> Starting Address   Ending Address    Purpose
> 0x00000000    0x00003FFF    Exception vectors.
> 0x00004000    0x03FFFFFF    Kernel image, boot structures, and drivers.

I put there some memory allocation information.
> 0x04000000    0x04FFFFFF    File load area.
> 0x05000000    0x053FFFFF    Simple read-time cache for file system
> metadata. Cache hits are serviced from memory, whereas cache misses
> result in disk access.
> 0x05400000    0x055FFFFF    Malloc zone: a simple memory allocator is
> implemented in BootX's libclite subproject. The starting and ending
> addresses of this range define the block of memory used by the
> allocator.

BootX should use openBIOS functions to allocate memory (as Yaboot
does...)
> 0x05600000    0x057FFFFF    BootX image.

This should be "load-base"
> 0x05800000    0x05FFFFFF    Unused (occupied by the Open Firmware image).
>
> So it should be loading OpenBIOS to address 0x05800000, and the BootX
> image should load to 0x05600000 (the latter does as it should,
> according to the debug output).

For the moment OpenBIOS is loaded at end physical memory and mapped at
end of space address (the reset vector is here).

Regards,
Laurent