Re: [uClinux-dev] Re: [linuxsh-dev] init problems on MMU-less SH-4

[Paul M. <le...@li...>]

On Sun, 2003-01-05 at 20:34, David McCullough wrote:
> I suspect that you are still running ELF programs.  When you turn off the
> MMU support in the kernel,  the rules for applications change a little.
> They cannot be paged in for example, and they have to be loaded (and
> relocated) at run time.  Normal elf programs are loaded at a fixed
> addresses and this cannot work without an MMU.
> 
> The uClinux guys use a program called elf2flt (ELF to flat) to make flat
> binaries that can be run without an MMU.  You can find it at:
> 
Okay, one issue with elf2flt. I've built a static busybox linked against
uClibc (which was built w/o HAS_MMU set), also using the sh-uclibc-
toolchain (which is also built w/o HAS_MMU). Now, this busybox itself
doesn't have any relocations in it, though it's still an ELF.

elf2flt currently bails and refuses to write the flt hdr/file if it sees
that the ELF doesn't have anything needing relocation. This happens
around line 900 of elf2flt.c from current HEAD by way of the
bfd_get_file_flags() HAS_RELOC check. If I comment this out, the flt
file is generated properly.

This brings up the question, if I have an ELF that was built with PIC
turned off, can binfmt_elf deal with it? or does it still have to pass
through binfmt_flat?

> 	http://cvs.uclinux.org/cgi-bin/cvsweb/elf2flt/
> 
> I don't believe there is SH support in it at the moment,  but it isn't a
> huge amount of work. Generally only a few relocation types need to be
> handled,

Currently I have R_SH_DIR32, R_SH_REL32, R_SH_GOT32 and R_SH_GOTPC
supported. I'll submit patches for this once the above mess is worked
out.

Regards,

-- 
Paul Mundt <le...@li...>