-----BEGIN PGP SIGNED MESSAGE----- Short version of question: - -------------------------- How do I load kernel modules from an initial ramdisk?
Long version of question: - ------------------------- This is a bit complicated (more so than appears from the short version of the question above), so I hope you will bear with me. I have a parallel port SparQ drive which I want to install Debian 1.3.1 on, to boot from my Windows NT laptop. To get the kernel to recognise the SparQ device I need to add the Parport modules to it <http://www.torque.net/linux-pp.html>. As my boot partition is going to be on the SparQ cartridge, obviously I can't put the modules there. Instead, I plan to put them on an initial ramdisk (initrd). The idea is that the kernel will load the initrd image from a small FAT partition on my NT's hard drive and load the modules from the ramdisk. Having done that, it will be able to recognise my SparQ media and continue booting from there. Much of what I need to do I have already done, or know how to do. For example: * I have got the kernel modules that I need to access the SparQ drive, and can insert these into the kernel using "insmod" from Linux on my old DX-66. * I have copied a full Debian installation onto a SparQ cartridge from my DX-66, and created a swap partition on it too. * I have made a FAT partition on my Windows NT machine to hold the kernel, initrd image file and lilo boot sector, for use with the NT boot loader. * I have set up lilo with the initrd option on my DX-66, and a test "linuxrc" file is running from the ramdisk correctly. * I know how to include a proc filesystem on my initial ramdisk and to change /proc/kernel/real_boot_device to point to my SparQ drive. * I know how to use mknod to create /dev/pda1 ... /dev/pda5 on my initial ramdisk as the device files for the partitions on my SparQ cartridge. What I cannot seem to do is to get a shell script that loads the kernel modules to run as linuxrc (ie. the file that automatically runs from the initial ramdisk). In fact, I can't get *anything* to run as linuxrc, aside from the test linuxrc file referred to in the documentation (a binary which prints out environment variables). When I use any other file as linuxrc, the kernel mounts the initial ramdisk and then does one of three things, depending on how I have set up lilo.conf: (a) If I have specified root=/dev/hda3 (the root partition on my DX 66) in lilo.conf, mounts this file system and runs init, without running linuxrc at all (apart from the test linuxrc referred to above). However I know that initrd has mounted properly, because it is accessible in /initrd when the system has finished booting from my hard disk. I can also manually execute linuxrc from there. (b) If I have specified root=/dev/pda1 in lilo.conf, I get a kernel panic. This indicates that the kernel modules to access the SparQ drive have not been successfully loaded. (As an aside, even the *test* linuxrc file which works under (a) above, doesn't work when I specify root=/dev/pda1, so it seems the kernel panic is occuring even before the linuxrc file is normally executed.) (c) If I have specified root=/dev/ram in lilo.conf, the kernel hangs as soon as it has mounted linuxrc. No kernel panic; it just hangs. (Again, interestingly, this hang seems to occur before the linuxrc file would normally be executed, because even the test linuxrc file that I can get to work under option (a) does not run when I specify root=/dev/ram.) The documentation suggests that *any* executable file can be run as linuxrc, including shell scripts, but nothing I have tried (apart from the test executable mentioned above) has worked. For example, I have tried using simple executables such as /bin/ash and /bin/ls as linuxrc files, but to no avail. I have also tried to run shell scripts as linuxrc (also copying the appropriate shell to the initial ramdisk) but with the same result. I figured that the reason must be because my pseudo-root file system does not have the correct files and libraries required by the linuxrc files that I need to run. The only files I have on my initrd file system are insmod (to load the modules), a shell (to run any scripts), /proc (so that I can change real_root_device), /dev (with a few files such as ttys1 and pda1) and the modules themselves. I don't know what files *must* be in the root file system to enable an executable to run or modules to be loaded, but apparently the files I have put there are not enough. Having concluded that this is the reason for my problem, I have tried to create a proper root file system on my initrd in various ways. First, I have copied the initrd root file system that is created by the Debian 1.3.1 rescue disk. This works fine if I don't mess with it (ie. the Debian install program starts up), but as soon as I try to modify it in any way (ie. to get it to load my modules, instead of installing Linux) it suffers the same problems as mentioned above; the kernel either ignores the linuxrc file and continues booting, gives a "kernel panic", or hangs. Next, I have tried using the files from a Slackware boot disk (rescue.gz) to populate my initial ramdisk. This has even less success than using the Debian rescue disk; once again it either ignores the linuxrc and continues booting, panics or hangs. Finally, I have tried to manually copy files that I think might be needed from my real root file system to the initial ramdisk file system. You guessed it; the same problem once again... So my questions are: 1. How can I create an initial ramdisk file system from which I can run simple shell scripts as linuxrc (basically, the script just needs to insert the kernel modules using insmod, change the real_root_device and exit)? 2. Alternatively, is there some other way for the kernel to load the modules it needs from the initial ramdisk, that doesn't involve the use of a linuxrc file at all? As you can probably tell from the above I have wasted many hours on this problem and I am tearing so much hair out that pretty soon I'll need a toupee. I would be eternally grateful for anyone who can shed some light on these intractable problems I am having. If you need any more information about my system setup, please don't hesitate to ask. Many thanks! - -- |--------- JEREMY MALCOLM <[EMAIL PROTECTED]> ---------| SIG of the day: [ ] Contact [ ] Web [ ] PGP [ ] Taglines #1 [x] #2 "I'm a lawyer." "Honest?" "No, the usual kind." | Linux, the choice of a GNU generation. | Are you the brain specialist? | "Could anyone pass the sodium chloride, please?" - Adric (5W) | The Nanites have lawyers? -----BEGIN PGP SIGNATURE----- Version: PGP for Business Security 5.5 iQB1AwUBNScnNb/mBljD2JABAQFFmQL8C3wY9L2iPu4nVKPJU6w52pcsV0ZO/2gu WHvTUcrD02TbTR59841zQ/JVNKcin1aUWaeHblgHLR358lekuAdGpKXaj4c8pzI8 CZvnYtsl8FCtar73RPi8Qf/FqO+U8rsb =oW+T -----END PGP SIGNATURE----- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
