Text 7896, 98 rader
Skriven 2006-11-09 23:07:00 av Paul Rogers (1:105/360.0)
     Kommentar till en text av Maurice Kinal
Ärende: Alternate kernels
=========================
 MK> I put /lib/modules/ in the rootfs rather then where /boot is.  /proc

I don't understand what you mean.  Are you saying you have 3 partitions?
On the host/development system I built, I have boot, swap, & root
partitions.

 MK> should  also be on the rootfs (initrd) and not as a directory on
 MK> the floppy since once the initrd is loaded onto / then it's
 MK> file structure is valid and is loaded into the ramdisk
 MK> rather then the entire floppy.  The kernel itself is on the
 MK> floppy but it requires the modules, procfs (and sysfs
 MK> although no applicable in your circumstance you may as well
 MK> know) to be on the rootfs and not the device/disk/whatever.
 MK> Offhand it looks like that is what the problem is.

That's what the initrd's linuxrc does--at least, I'm working out what it
needs to do.  It's copying the files from the floppy to /lib/modules/kv/
on the RAM, and then doing the insmod.  But for the floppy I don't need
kmod loading and unloading modules.

 MK> The floppy only needs the kernel, a few basic /dev's
 MK> (/dev/ram0 for sure) for booting and possibly a few /etc's
 MK> depending on the bootloader requirements.
 MK> /lib/modules/kv/* should be uncompressed in most
 MK> circomstances.  I know busybox's module utilities cannot be
 MK> compressed or they will fail to load and they are in the
 MK> rootfs and not on the actual floppy although the rootfs has
 MK> to be there.  The kernel has to be on the floppy and not in
 MK> the rootfs.

Yes, got all that.  Been working on getting linuxrc right for a while
now.

 MK> Confused now?  I know I was but found by trial and error
 MK> what goes where depending on the kernel version and
 MK> bootloader.  I am sure I saw a good howto on this

/usr/src/linux/Documentation/initrd.txt?  There's also an OLD file in
the LDP.

 MK> somewhere.  What does trinux suggest?  Follow their
 MK> strategy and it should work at least as good.  If you have
 MK> a trinux image file you should be able to dd it to a floppy
 MK> and mount it to see their structure for the floppy.  My
 MK> guess is that /lib/modules/kv/* is inside their initrd,
 MK> whatever that is called.

Yep.  Been there, done that.  But actually they get modules from a
directory on the floppy--something one can copy there from a DOS box.

I wasn't making myself clear.  I didn't have extra time this morning.  I
think I've got the general idea about what to do in the linuxrc--though
I'm still working out details.  It's similar to what trinux does, but
I'm modifying it.

My problem is with using a full-up 2.4.21 host/development system,
trying to build a kernel for the floppy that's different than the "host"
system's kernel.  I try to preserve all the files for the host's kernel
that are the result of kernel building, change to the .config I want for
the floppy's kernel, build the kernel/modules, copy them to the floppy
development directory, then replace the files for the host system so
it's consistent.  When I do that there seems to be something else that
gets modified.

I'm not saving/restoring the right things, I guess.  On my list are:
/usr/src/linux-2.4.21/[.config,System.map],
/usr/src/linux-2.4.21/arch/i386/boot/bzImage,
/lib/modules/*

 PR> system kernel rebuild with the right config file.  But now when the
 PR> system gets to the real init and wants to set "/sbin/modprobe" in
 PR> /proc/kernel/sys/modprobe for kmod to use in the system kernel, the
 PR> proc file isn't there.

 PR> For some reason I don't understand, I'm getting some "bleed-through"
 PR> on my kernel builds.

 PR> different "test" kernel for the floppy.  Any idea what I'm missing?

I'm seeing this evidence that when I built the kernel/modules for the
floppy, moved that aside, then rebuilt the kernel/modules for the host
development system, I'm getting a kernel that still has some parms from
the floppy's .config file.  Yeah, it seems obvious I'm getting the
.config files confused, but I've double-checked that, and I don't see
how--unless there's something left over that make clean doesn't clean.
Or something in the 2.4 make's _insists_ on only working in
/usr/src/linux, and doesn't like me renaming things in the source tree
with the kernel version.  I don't understand WHY, but maybe?

Paul Rogers, paulgrogers@yahoo.com                       -o)
http://www.angelfire.com/or/paulrogers                   /\\
Rogers' Second Law: Everything you do communicates.     _\_V

... Blessed are the pessimists, for they made backups.
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