On Wednesday, August 7, dkwokiware.com.au wrote:
>
> I am experimenting to do mini BSD. I have read a few articles embsd,
> mybsd, picoBSD, etc. However, I like the idea which was used to produce
> OBSD installation disk, floppy31.fs.

Neat... ok, let's get you started...

> Of course, I have problems in booting up the resulting image. When I boot
> the system with the compiled kernel. I have these messages:
> entry point at 0x100020
> fatal page fault in supervisor mode
> trap type 6 code e0fa0000 eip e01a5ab5 cs fe0008 efalgs 1020 cr2 dff84128
> cp1 0panic= trap type 6 code= e0fe0000, pc-e01a5ab5

Yeah, that is bound to happen at times...

[snip]
> My miniroot is 12.5M large so I created a virtual disk of 14M, 28000 sectors.

Hmm, what makes you think a 14MB kernel will boot? Then again, what makes you
think it won't... Well...

[snip]
> So folks, that was my journey so far. If anyone can give me some pointers
> I will be much appreciated.

Yup, have a look in 2 different places. The boot code in /boot will need to
make sure that your kernel is being loaded in a contiguous piece of RAM. Note
that some machines have a hole at 16MB. You 14MB kernel (loaded at 1MB) is
getting close to that possibility. Just pointing it out, not a real problem
yet.

Second place to look would be in machdep.c/locore.s within the i386 tree. It
is the place the kernel is first mapped. Chances are that the code there does
not have enough magic to map 14MB worth of a binary into kernel space. It will
take come ooommmpphh in order to get that working...

Oh, and the last place to check would be most of uvm/pmap stuff, I'm not sure
how the i386 pmap will handle having 14MB worth of kernel text/data mapped.

Good luck,

--Toby.

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