Re: Embedding rootfs with kernel

Re: Embedding rootfs with kernel

[Marc St-Jean]

Alexander Voropay wrote:
> 
> 
>  >I was also looking at initramfs but from documentation I found it,
>  > appears to expand the cpio.gz into a tmpfs (i.e. RAM) before using
>  > it.
> 
>  Read this nice article:
> http://www.linuxdevices.com/articles/AT4017834659.html
> 

Thanks Alexander, I'd read it many months ago, it does clarifies a few
issues. Another article on various methods of preparing the initramfs is:
"Including an initramfs Intialization Program in the Kernel"
http://lldn.timesys.com/docs/initramfs?elq=1EE1D775A62A4EF68F0A3E9AEC666D0D

Neither of these seem to help with regards to embedding a read-only
file system. It seems like there is no officially supported way of doing
this. Presumably these types of file systems are meant to only be used
separate from the kernel image, such as in a flash partition.

I guess we can continue to use our current method, but I was hoping
to eliminate any changes to non-platform code such as vmlinux.lds.S.

Marc

Re: Embedding rootfs with kernel

[Marc St-Jean]

I was also looking at initramfs but from documentation I found it,
appears to expand the cpio.gz into a tmpfs (i.e. RAM) before using
it.

Since the cpio.gz is embedded into the kernel (i.e. RAM again),
won't this take twice the memory relative to embedding a
cramfs/squashfs directly in the kernel?

We only need read-only access and I believe these file systems
can be read in their compressed form without expanding and
consuming more RAM.

Marc


Domen Puncer wrote:
> On 05/02/07 12:41 -0800, Marc St-Jean wrote:
>  > What is the MIPS-way of embedding the rootfs with the kernel?
> 
> For 2.6.x (on all? architectures) initramfs.
> 
> 
>         Domen
> 

Re: Embedding rootfs with kernel

[Domen Puncer]

On 05/02/07 12:41 -0800, Marc St-Jean wrote:
> What is the MIPS-way of embedding the rootfs with the kernel?

For 2.6.x (on all? architectures) initramfs.


	Domen

Embedding rootfs with kernel

[Marc St-Jean]

What is the MIPS-way of embedding the rootfs with the kernel?

Our method involves modifying the vmlinux.lds.S linker script to pull in our
'romfs' section. I don't see any other platform code doing this so there must
be a more "standard" approach.

Apparently there was support in linux 2.4 (a patch possibly?) which would
look for supported file system magic numbers past the end of the kernel.
So you could just cat the rootfs to the end of the kernel binary and go
on with life.

I've tried this with linux-mips.org code base and it doesn't appear to work.
Any pointers would be appreciated.

Marc