Syslinux - Jan 2006 - Patch to add Symbols/segments loader for mboot.c

Hello,

I use Tim's mboot.c32 to load multiboot kernels over pxelinux. However, some
kernels require the symbol table and other information in the ELF section
header table to be able to load properly. This functionality is not present
in mboot.c now, so I added support for it.

The patch is attached. It would be great if you can push this into the next
release of syslinux so ELF multiboot kernels are fully supported.

The patch is diff'ed against syslinux-3.11.

thanks,
Ram

Ram Yalamanchili wrote:
> Hello,
> 
> I use Tim's mboot.c32 to load multiboot kernels over pxelinux. However,
some
> kernels require the symbol table and other information in the ELF section
> header table to be able to load properly. This functionality is not present
> in mboot.c now, so I added support for it.
> 
> The patch is attached. It would be great if you can push this into the next
> release of syslinux so ELF multiboot kernels are fully supported.
> 
> The patch is diff'ed against syslinux-3.11.
> 
Could you resend with the patch actually applied?  Please include the 
original description in the resend.

	-hpa

Hi Ram,

Thanks for the patch.  I've tidied it up a little and I'm testing it
now.  I have a question about the code to load additional sections out
of the section table.  Why do you use place_module_section() for this?
Since the sections come with their virtual addresses specified in the
ELF binary, shouldn't you be using place_kernel_section()?

Cheers,

Tim.

On Fri, Jan 13, 2006 at 05:45:54PM -0800, Ram Yalamanchili
wrote:
> Hi Tim!
> 
> I use your mboot.c32 to load multiboot kernels over pxelinux. I appreciate
> the work you have done on this. However, some kernels require the symbol
> table and other information in the section header table to be able to load
> properly. This functionality is not present in mboot.c now, so I added
> support for it. I haven't touched a.out however.
> 
> The patch is attached. It would be great if you can push this into the next
> release of syslinux so we dont have to distribute patched versions of
> mboot.c32.
> 
> The patch is diff'ed against syslinux-3.11. I wasn't sure who is
maintaining
> this, so i'll send a copy of this message to the syslinux mailing list
too,
> so Peter Anvin can have a look.
> 
> thanks,
> Ram

-- 
Tim Deegan                           (My opinions, not the University's)
Systems Research Group
University of Cambridge Computer Laboratory

Hi Ram,

On Mon, Jan 16, 2006 at 04:41:00AM -0800, Ram Yalamanchili
wrote:
> The ones which are being loaded in my patch are those sections which
> have a VA of 0 (invalid) and thus not mapped to any program segment. If
> you look in the 2nd if() statement of the section loader code, you will
> see I don't load any section if it already has a VA. 
Ah!  Thinko on my part, I read "!=" as "==".

Yep, looks good to me, and doesn't break anything else that I was using
it for.  hpa, can this patch be included?  It's at
http://www.cl.cam.ac.uk/~tjd21/tmp/shtab.patch . (I've tidied up the
layout a little and removed some compiler warnings from Ram's version).

Cheers, 

Tim.

-- 
Tim Deegan                           (My opinions, not the University's)
Systems Research Group
University of Cambridge Computer Laboratory