On Aug 18, 2008, at 9:17 PM, Miklos Vajna wrote:
Hi!
I recently started to search for a solution to boot a Linux-2.6-based
kernel in qemu-system-ppc.
Google found two of your interesting patches:
http://patchwork.ozlabs.org/linuxppc/patchcontent?id=13689
http://patchwork.ozlabs.org/linuxppc/patchcontent?id=13690
...
Sadly the build fails at your qemu.c, with:
BOOTCC arch/powerpc/boot/qemu.o
arch/powerpc/boot/qemu.c: In function 'tree_fixups':
arch/powerpc/boot/qemu.c:203: warning: implicit declaration of
function 'dt_find_initrd'
arch/powerpc/boot/qemu.c: In function 'platform_init':
arch/powerpc/boot/qemu.c:230: error: 'struct platform_ops' has no
member named 'find_vmlinuz'
make[1]: *** [arch/powerpc/boot/qemu.o] Error 1
make: *** [zImage] Error 2
Two questions:
1) Do you remember what was the exact commit you worked with, where
qemu.c compiled fine? (In case you have newer patches somewhere, I'm
interested as well :) )
From those messages, there were other patches posted about the same
time that did some radical splits to the zImage infrastructure code,
allowing it to become a helper instead of just a contained image.
And I do have later patches that were working (better). I have even
booted a linux-next kernel just before 2.6.27 opened, after doing some
fixups. However, I suffer from wanting to perferct the function of the
patches and never get the base part out :-). For instance, when
working with 2.6.27, I got ISA memory working and some video output.
Also, the ide-generic driver now has to be enabled on the command line
to give the same function we previously had. That, combined with
kernel for ppc-qemu is my hobby and my work keeps interrupting me.
The current state is: Rob Landley's Firmware Linux has a ppc_rom.bin
(and source) written by me that probes qemu nvram for the size of
memory, location of a command line (-append) and initrd (-initrd),
patching a device tree linked into it, then parses the kernel (or other
elf file) loaded via -elf a kernel and jumps into it whereever it was
loaded. The kernel has a corresponding platform patch that only
recognises qemu (based on the kernel patch you found). The version Rob
has works on 2.6.25.9 with serial, ide, and isa ne2000. Since then I
got isa memory to enable video (with hacks and you only see 1/4 of the
screen).
http://landley.net/hg/firmware/raw-file/6f1e69d7e7f5/sources/toys/make-
ppc_rom.tar.bz2
http://landley.net/hg/firmware/raw-file/59e22ea53e6a/sources/patches/
linux-ppcqemu.patch
http://landley.net/hg/firmware/raw-file/0d8e80202e94/sources/patches/
linux-2.6.23-ppcne2khack.patch
2) I'm not exactly sure about the build process in the case of qemu,
using your patches.
Am I right about I just have to compile the kernel, I'll be given a
ppc_rom.bin and the usual vmlinux file, then I can boot these with
qemu?
The version that you have built a rom out of the code in
arch/powerpc/boot after patching. The new version builds the rom in a
shell script. Either way, it activated by calling it ppc_rom.bin and
pointing QEMU's library drectory to it with the -L flag. This code
works for qemu -kernel when the kernel is patched to recogonise the
qemu platform specified in the device-tree.
Going forward, it probably needs to become a dtbImage or a combination
rom and optional image.
Hopefully the rest is clear, currently I have 2.4.36.1 in qemu and it
would be really time to upgrade to 2.6 :)
People were successfully able to get arch/ppc kernel to boot as last
ase 2.6.26, at least until they got to userspace. That doesn't provide
a way forward, as ppc is now removed, but it may provide a temporary
option.
I can't promise a timeframe, but I do want to get the patches updated
and out.
milton
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