Re: 43p: Install kernel boots, generic not

Hi,

> > -----------------------snip------------------------
> > 0 > boot net
> > LOAD: Waiting 60 seconds for Spanning Tree
> > BOOTP R = 1 BOOTP S = 1
> > FILE: generic_com0.fs
> > Load Addr=0x600000 Max Size=0x10000000
> > Packet Count = 100...FINAL Packet Count = 5181   Final File Size = 2652339 bytes.
> 
> Mmmm. It should be possible to netboot a copy of the NetBSD boot
> loader and then have it load the kernel (this is what Sun boxes do).
> Of course it means you need a prep NetBSD boot loader that can be used
> that way (I don't know if that is the case)

I haven't seen a bootloader for prep in the NetBSD tree. Either yaboot
(which does not work out of the box:
https://www.netbsd.org/ports/macppc/faq.html#yaboot) or grub2 will be
candidates, but I think I'll start with yaboot - it's just so much smaller.

> Another option might be to build a binary which is a compressed kernel
> with a small loader which decompresses and then jumps into the kernel
> - which would give a little more headroom, but still eventually fall
> into the size limit.

Nah, the images mkbootimage creates are already compressed, else I
would not be able to boot a 4MB kernel, which is the more-or-less
bare minimum.

> > > Do kernel modules work on port-prep - an easy way to test might be to
> > > try 'modload efs' and then 'modstat'. That could be a way to keep the
> > > base kernel down while still being able to support everything
> >
> > Well, the first kernel with the option enabled died on boot-up,
> > is there something to watch out for? It was not selected in the GENERIC
> > kernel for prep anyway, so I think that's more work for later...
> 
> So to confirm - adding
> 
> options         MODULAR         # new style module(7) framework
> options         MODULAR_DEFAULT_AUTOLOAD
> 
> fails to load the kernel (could this also be a size thing?)

No, it did not fail to *load* such a modular kernel:

------------------------snip-----------------------
0 > boot net 
LOAD: Waiting 60 seconds for Spanning Tree
BOOTP R = 1 BOOTP S = 1  
FILE: mod.fs
Load Addr=0x600000 Max Size=0x10000000 
FINAL Packet Count = 3872   Final File Size = 1982350 bytes.



>> NetBSD/prep BOOT, Revision 1.9 (Sun Jul  7 15:18:27 UTC 2019)


Boot: 
Loading in()
No such device - Configured devices are:
 sd
in memory kernel
3688124+165540 [215984+204620]=0x413c6c
start=0x100000
------------------------snip------------------------------

It dies when the kernel has been decompressed and gets started by
the minimal boot loader of the kernel image. So I think I'll leave
the modules for later ;-)

CU,
Uli
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