Re: [Bootldr] netbsd support

Hi Jamey,

first: I'm rebuilding my toolchain a.out. I figure that's a good way
to get started. then we can add the elf bits.

the three questions you posed I didn't really know the answers to, but after
delving through bootldr, blob, the netbsd hpcboot wince code, and
the 'arm system on a chip architecture' book I ran out and digested
instantly, I'm still not certain, but I'll take a whack at it.

at the moment,
where it's loaded: DRAM_BASE
then gets copied to: 0xF0000020
mmu enabled: yes: by main(). linux disables the mmu and works some magic.
     did the netbsd bootldr _ever_ work? does netbsd do this itself in locore?
mmap: I guess I'll be digging in through the netbsd kernel bootstrap now...

I'm thinking that if it ever worked, the mmap bit is already there.
I'm assuming there's a good reason linux frobs the mmu before jumping to the
kernel, I'm just to fried at the moment to think it through.

what's involved in booting an elf object? and why 0xF0000020?

it's a start. I'm learning. tnx for your patience. I hope it'll pay off
in a bootldr that boots netbsd.

Joe
battlej@groove.com

On Mon, Feb 04, 2002 at 08:28:26AM -0500, Hicks, Jamey wrote:
> Joe,
>
> I'm moving this discussion to netbsd@handhelds.org.
>
> The bootldr was trained to boot netbsd a.out executables, but that code
> has not been tested in eons. If netbsd is using a new executable
> format, we'll have to add code to support it. We also need to know what
> netbsd expects in terms of where the executable is loaded in dram,
> whether it wants the MMU enabled and what memory mapping it wants if it
> wants the MMU enabled. Do you know the answers to those questions?
>
> Jamey
>
> > -----Original Message-----
> > From: battlej@luminous.groove.com [mailto:battlej@luminous.groove.com]
> > Sent: Monday, February 04, 2002 3:46 AM
> > To: Hicks, Jamey
> > Subject: Re: [Bootldr] netbsd support
> >
> >
> >
> > patches! of course. but you've got to give me a clue in
> > getting the thing
> > booted. (please) I've never written a bootloader, but I've got lots of
> > time, energy, and patience. I _will_ make this work. I just need a
> > bit of a clue. (not even a big one. I'm a quick study)
> >
> > info: I'm building netbsd-current. it uses the new toolchain
> > (in netbsd
> > terminology.. it's a gcc2.95.3) and builds an elf target.
> > is there some magic that needs to happen for an elf object?
> > is there some special way to tickle the mmu before jumping to
> > the fun bits?
> > would a.out be easier?
> > I'm booting on an ipaq and assabet. I can prolly get a casio
> > too, but I'd
> > hate to risk bricking something that isn't mine. the assabet
> > is the toy
> > of choice here, for the jtag.
> >
> > thanks,
> >
> > Joe
> > battlej@groove.com
> >
> > On Sun, Feb 03, 2002 at 06:03:38PM -0500, Hicks, Jamey wrote:
> > >
> > > No one else is booting NetBSD on the ipaq as far as I know.
> > Please send
> > > patches.
> > >
> > > Jamey
> > >
> >
Received on Mon Feb 4 10:14:38 2002