Linux w/o disk, network, or ROM

Linux w/o disk, network, or ROM

[Jeffrey W. Daugherty]

All,

I am trying to replace a proprietary OS on a proprietary
board that only has a PPC750 and 192MB of RAM.  The only
means of communication to this board is via shared memory.

I am able to configure the kernel with RAMDISK, and I can
boot the kernel along with an initrd image.  The kernel
recognizes the initrd image containing an ext2 root filesystem.
Using a simple console which dumps kernel text messages
to the share memory, I see the messages:

RAMDISK: ext2 filesystem found at block 0
RAMDISK: Loading 4096 blocks [1 disk] into ramdisk...done
Freeing initrd memory: 4096k freed
Kernel panic: VFS: Unable to mount root fs 01:00

I've tried setting ROOT_DEV to MKDEV(RAMDISK, 0) in setup.c
and cmdline argument "root=/dev/ram".

Does anyone have any suggestions?  What might be missing either
in kernel configuration or platform_init()?  Help!

--
Jeffrey W. Daugherty
(630)713-6511
jwdaugherty@lucent.com


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Re: Linux w/o disk, network, or ROM

[John W. Linville]

"Jeffrey W. Daugherty" wrote:

> I've tried setting ROOT_DEV to MKDEV(RAMDISK, 0) in setup.c
> and cmdline argument "root=/dev/ram".
>
> Does anyone have any suggestions?  What might be missing either
> in kernel configuration or platform_init()?  Help!

Are you sure that the kernel is recoginzing your command line
parameters?  It should echo them out in an earlier boot message.

My guess is that you have a mistake somewhere in passing the command
line parameters to the kernel, leaving the kernel unable to find it's
root fs.  YMMV... :-)

John

P.S.  Another possibility is that your initrd image isn't getting
uncompressed correctly or to the correct location...
--
John W. Linville
LVL7 Systems, Inc.

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Re: Linux w/o disk, network, or ROM

[Greg Griffes]

> Does anyone have any suggestions?  What might be missing either
> in kernel configuration or platform_init()?  Help!
>

Jeffery,

What boot loader are you using?

If you are using the "simple" boot loader,
you may need a call to parse_bootinfo(find_bootinfo());
in platform_init().  That call will read the bi_record
struct built by the boot loader and initialize globals
such as initrd_start and initrd_size.

Greg


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