Re: initrd problem

[Kumba <kumba@gentoo.org>]

Ed Martini wrote:
> Background:
> 
> I'm trying to get 2.6.11 to run on a MIPS Malta board with Yamon.  The 
> kernel that comes with the board is 2.4.18 with an embedded ramdisk that 
> runs some scripts to install RPMS via NFS or CD-ROM.  The kernel is 
> converted to s-records via objcopy(1), and loaded into memory via tftp.  
> I want to do something similar with 2.6.latest.
> 
> Problem:
> 
> On or about Nov 21 of last year, the CONFIG_EMBEDDED_RAMDISK disappeared.
> 
> http://www.linux-mips.org/archives/linux-mips/2004-11/msg00135.html
> 
> In it's place it is suggested to use the tools in arch/mips/boot, so I 
> tried it.  I can cross-compile the kernel, and I get an ELF vmlinux.  I 
> can convert it to ecoff with elf2ecoff, and attach an initrd image with 
> addinitrd.  The problem begins here.  I end up with an ecoff format 
> kernel which is not recognized by objcopy(1), and therefore no s-records.
> 
> It seems there is a program called gensrec that would do the job, but 
> google doesn't want to tell me where to get it.  Some IRIX binary perhaps?
> 
> Solution?
> 
> Should I put CONFIG_EMBEDDED_RAMDISK and its ilk back into my kernel, or 
> write an ELF version of addinitrd?  Other ideas?
> 
> Thanks in advance.

The future is purportedly in the feature known as initramfs.  See the file 
Documentation/early-userpace/README for more details on how that is supposed 
to work.

That said, I tried initramfs a few times, but either due to lack of 
understanding, or broken support code in 2.6.10, I couldn't get it to properly 
load an initrd bundled in, so I forward-ported a patch I wrote that originally 
fixed CONFIG_EMBEDDED_RAMDISK to work with any ABI to 2.6.10, and it worked 
rather well.  I'm sticking with this method until I find more/better docs on 
how to use initramfs properly.

If you're interested, the patch I use can be found here:
http://dev.gentoo.org/~kumba/mips/misc/misc-2.6.10-add-ramdisk-back.patch [2.6.10]
http://dev.gentoo.org/~kumba/mips/misc/misc-2.6.11-add-ramdisk-back.patch [2.6.11]


--Kumba

-- 
"Such is oft the course of deeds that move the wheels of the world: small 
hands do them because they must, while the eyes of the great are elsewhere." 
--Elrond