Question on the microcore Linux kernel

[lid]

The links under chapter "initramfs" here:
http://www.landley.net/writing/
should pretty much cover the whole subject.

To me it looks like the patch is replacing ramfs with tmpfs, though from what I had read I had always understood that tmpfs could be enabled without a patch, so I am not really sure about that.

Thanks for the link. Looks it has a lot of good info.

I recompiled the tinycore kernel and on pxeboot, it immediately hit the following line:

panic("No init found.  Try passing init= option to kernel. "
         "See Linux Documentation/init.txt for guidance.");

I kind of suspect my kernel didn't unpack the initrd cpio file correctly so it couldn't find the init script to run. Does anyone have any suggestions where to look?

[gerald_clark]

Show your pxe entry.
See the network booting examples in the wiki.

[lid]

Show your pxe entry.
See the network booting examples in the wiki.

Which pxe entry? pxelinux.cfg/default?

It boots ok if I just use the TC kernel and core.gz.
It only failed when I compiled the kernel downloaded from linux-3.0.21-patched.txz and config-3.0.21-tinycore. It must be something missing from my own config and compiling process.

[tinypoodle]

Did you update the cpio archive to reflect changes of modules?

[gerald_clark]

Why are you recompiling the kernel?

[lid]

Did you update the cpio archive to reflect changes of modules?

Don't quite understand this. What module is changed? 

[lid]

Why are you recompiling the kernel?

Must want to understand the TC kernel patch by playing it.

[lid]

Did you update the cpio archive to reflect changes of modules?

I am not sure I understand your point. 

I don't really want to change any kernel modules but maybe accidentally I did it by running make oldconfig using the downloaded config file. There is indeed a diff for .config after make oldconfig.  But I am not sure how I need to update cpio.

Can you explain?

[tinypoodle]

Noone could possibly ever guess what you did without you providing exact documentation...

Your safest bet might be to follow regular procedure of installing different kernel.

[lid]

Noone could possibly ever guess what you did without you providing exact documentation...

Your safest bet might be to follow regular procedure of installing different kernel.

Here is what I did step-by-step. Prior to these, I was able to pxeboot the microcore with vmlinuz and coregz as initrd.

1. download linux-3.0.21-patched.txz, unpack to a directory linux-3.0.21/
2. download config-3.0.21-tinycore and copy it to linux-3.0.21/ as .config
3. cd linux-3.0.21/, do make oldconfig and accept all defaults
4. make
5. copy linux-3.0.21/arch/x86/boot/bzImage to tftpboot/ directory as vmlinuz (overwrite the previous one)
6. try pxeboot again.

Anything I might have missed in the above?

[curaga]

"accept defaults" sounds wrong, as the config is for the same version, it should ask nothing.

[lid]

"accept defaults" sounds wrong, as the config is for the same version, it should ask nothing.

I was also wondering too about this. make oldconfig with the existing .config should be enough. But maybe the kernel source doesn't match the config file.

Can I just do make without "make oldconfig"?

[curaga]

It does match, if you grabbed the same versions (3.0.21 instead of 3.0.3). Something in your environment is weird.

One of the *config targets is necessary; if you don't run any of them, the makefiles will run oldconfig for you.

[tinypoodle]

You could run a diff between some newly built modules and their correspondent ones in stock cpio archive.

[lid]

It does match, if you grabbed the same versions (3.0.21 instead of 3.0.3). Something in your environment is weird.

One of the *config targets is necessary; if you don't run any of them, the makefiles will run oldconfig for you.

Ok, I made some progress. I ran make oldconfig using the 64 bit config file and this time it passed without asking questions. So I rebuilt the kernel and pxebooted. This time there is no kernel panic. However the problem now is the boot process stops after this:

modprobe: chdir (3.0.21-tinycore 64+) No such file or dir
...
Switching to clocksource tsc.

Maybe I am missing some modules in the initramfs ?

David