cannot link with ld

B2T · 10-15-2005, 04:11 PM

Hello

I can't link my .o files with ld, it sais "section .data overlaps section .text" and that there is not enough room for headers. Im using binutils 2.16.1.
The linker script I use:

Code:

OUTPUT_FORMAT("binary")
ENTRY(start)
phys = 0x00100000;
SECTIONS
{
  .text phys : AT(phys) {
    code = .;
    *(.text)
    . = ALIGN(4096);
  }
  .data : AT(phys + (data - code))
  {
    data = .;
    *(.data)
    . = ALIGN(4096);
  }
  .bss : AT(phys + (bss - code))
  {
    bss = .;
    *(.bss)
    . = ALIGN(4096);
  }
  end = .;
}

Most files are assembled by gcc 3.4.0, but one of them is produced by nasm 0.98.39.

Thx for your help

ioerror · 10-15-2005, 05:38 PM

Is there some reason you're using ld? You generally don't need to use ld directly. What happens if you try to link them with gcc?

B2T · 10-15-2005, 05:57 PM

It is because gcc can't produce flat binaries. (or can it?)

paulsm4 · 10-15-2005, 10:27 PM

I'm curious: what's a "flat binary"?

I've never, *ever* had a occasion to write an "ld" parameter script like you're doing.

I'm not saying it's wrong - but I am curious: "Why???"

Thanx in advance .. PSM

PS:
What environment is this for? Straight Linux? Some kind of embedded environment?

B2T · 10-16-2005, 03:37 AM

flat binary is a kind of executable format with very little overhead, they are lightweight and contain only little code beside the code that you wrote. Out of curiosity, I only want to tackle around in programming without an operating system (altough i do not want to make one). As a starting point however, I've found a nice tutorial at http://www.osdever.net/bkerndev/index.php?the_id=90 (that's where I got the script from). It is the best to use such kind of binaries as they can be loaded directly by the BIOS, it might be possible however that i dont need it as my programme is loeded by grub, which might be able to load other file formats as well. But if i stick with this format, all i need to do if i decide i want my own verysimple boot loader, is to write some asm to switch to protected mode. Note that im currently experimenting in this area and am not an expert or something like that.

B2T · 10-16-2005, 05:48 AM

Header error solved by not using the cross-compiled ld, but the original one in the cygwin download.

But what in my code could cause overlapping sections? This problem is still present.