Re: GRUB on OLPC / XO

[Robert Millan]

On Tue, Jan 15, 2008 at 12:31:30PM +0100, Marco Gerards wrote:
> Robert Millan <address@hidden> writes:
> 
> Hi,
> 
> > I've been working for a few hours in a GRUB port to i386/OFW.  There's
> > quite a bit of things that need cleanup/fix before it can be considered
> > complete, but it's in a stage that boots and lets you do basic things (like
> > listing storage devices).
> 
> OLPC is OF!?  I didn't expect this :-).  Who made the firmware?

Mitch Bradley (author of Open Firmware).

> > I'll be gradually integrating this into official GRUB tree.  In the 
> > meantime,
> > if you want to try it:
> >
> >   - checkout GRUB cvs (grub2 module)
> >   - apply attached patch
> >   - ./autogen.sh && ./configure --with-platform=ieee1275 && make kernel.elf
> >
> 
> Great!  I'll just review the patch! :-)

Please don't.  It's not meant for review, was just a proof of concept.  The
patches I actually intend to get merged are being sent separately (see my later
mails on this).

Oh well, too late.. :-)

> > +COMMON_ASFLAGS     = -m32 -nostdinc -fno-builtin
> > +COMMON_CFLAGS      = -ffreestanding -mrtd -mregparm=3
> > +COMMON_LDFLAGS     = -nostdlib -static -lgcc
> 
> Why mregparm?  I don't think we need this for OF?  Do you call
> assembler functions?

OFW expects %eax to be the first parameter in callbacks.  Other than this,
I assumed -mregparm is a useful size optimization.  Is that not it?  Why
do we have it on i386-pc then?

> >    /* Load pre-loaded modules and free the space.  */
> >    grub_register_exported_symbols ();
> > -  grub_load_modules ();
> > +//  grub_load_modules ();
> 
> Why?

I still don't know.  Memory corruption I think.  I'm investigating.

> > diff -x '*.mk' -x '*~' -x CVS -x .svn -x configure -x config.h.in -Nurp 
> > ../../grub2/kern/powerpc/ieee1275/cmain.c ./kern/powerpc/ieee1275/cmain.c
> > --- ../../grub2/kern/powerpc/ieee1275/cmain.c       2007-12-30 
> > 09:52:05.000000000 +0100
> > +++ ./kern/powerpc/ieee1275/cmain.c 2008-01-12 03:12:01.000000000 +0100
> > @@ -58,7 +58,7 @@ grub_ieee1275_find_options (void)
> >    grub_ieee1275_finddevice ("/options", &options);
> >    rc = grub_ieee1275_get_property (options, "real-mode?", &realmode,
> >                                sizeof realmode, 0);
> > -  if ((rc >= 0) && realmode)
> > +//  if ((rc >= 0) && realmode)
> >      grub_ieee1275_set_flag (GRUB_IEEE1275_FLAG_REAL_MODE);
> 
> Ehm?

Nothing to see here.  Move along.... :-)

> > -  while (i < sizeof (available))
> > +  while (i < sizeof (available) && available[i])
> >      {
> >        grub_uint64_t address;
> >        grub_uint64_t size;
> >  
> > -      address = available[i++];
> > +      address = grub_be_to_cpu32 (available[i++]);
> 
> Why do you do this?  Isn't this information available in native byte order?

See my other mail about IEEE-1275 and endianess.

> > diff -x '*.mk' -x '*~' -x CVS -x .svn -x configure -x config.h.in -Nurp 
> > ../../grub2/term/ieee1275/ofconsole.c ./term/ieee1275/ofconsole.c
> > --- ../../grub2/term/ieee1275/ofconsole.c   2007-12-25 12:10:47.000000000 
> > +0100
> > +++ ./term/ieee1275/ofconsole.c     2008-01-12 03:09:02.000000000 +0100
> > @@ -369,9 +369,6 @@ static struct grub_term grub_ofconsole_t
> >      .getwh = grub_ofconsole_getwh,
> >      .gotoxy = grub_ofconsole_gotoxy,
> >      .cls = grub_ofconsole_cls,
> > -    .setcolorstate = grub_ofconsole_setcolorstate,
> > -    .setcolor = grub_ofconsole_setcolor,
> > -    .getcolor = grub_ofconsole_getcolor,
> 
> Why do you do this?

GRUB still wants to set light-gray/black color when run over serial port
(or OFW terminal which could pipe to serial port).  This is very ugly
when your serial port is mapped to a black/white gnome-terminal.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call, if you are unable to speak?
(as seen on /.)