Re: Move loader.c out of the kernel

[Robert Millan <rmh@aybabtu.com>]

On Wed, Apr 01, 2009 at 10:52:26PM +0900, Yoshinori K. Okuji wrote:
> On Tuesday 31 March 2009 17:56:24 phcoder wrote:
> > With a new swing in normal.mod splitting I think we should reconsider
> > this patch. It's useless to keep loader.c in kernel without boot
> > command. IMO it should be moved either to a perate boot.mod (my
> > preference) or to minicmd.mod (not a good option IMO)
> 
> As I said, rescue mode is not quite useful without any loader. So the loader 
> interface should be built into the kernel, and the boot command should be as 
> well naturally.

This presses for more space into core.img, which is highly constrained
(specially in weird combinations like raid + lvm or crypto in the future).

Why is a loader so important for rescue mode?  If the loader would work, it
means you can read files, so it should be able to load the rest of modules
as well.

When user is dumped to rescue mode, usually (at least for reports I dealt with
in debian) it means GRUB has a bug or didn't setup itself properly, and the
/boot/ directory can't be accessed.  A loader wouldn't help in these
situations.

Also, how do you determine which loaders belong in kernel?  There can be
many specialized loaders like the linux one.  Or we could just put multiboot,
but the Multiboot loader is quite complex already, and it still has room
for growing.  Maybe the answer is to write a very simple Multiboot loader
and put that in kernel?

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."