ld behavior on different architectures

[Constantine Kousoulos]

Hello all,

First of all, excuse me if i'm asking a naive question. I'm a 
complete noob at using linker scripts (and generally ld), so 
please give me a helping hand.

I use the same linker script when building a (non linux) kernel 
natively on i386 and on amd64. The linker script defines the first 
section to be one called 'boot'. This is where i put multiboot 
headers so that they are within the first 8 bytes of the kernel 
image. Grub succesfully retrieves the headers from the i386 build 
but not from the amd64 build. This is not a grub question.

Does the linker's behavior change across different architectures? 
Is is possible that the 'boot' section is *not* at the beginning 
of the file on amd64?

Thanks,
Constantine


Here's my linker script:

start_offset = 0x100000;
kernel_offset = 0xc0000000; (0xffffffff80000000 when building on 
amd64)
real_start = start - kernel_offset;
boot_stack_size = 4096;

ENTRY(real_start)

SECTIONS
{
  . = (start_offset + kernel_offset);

  .boot ALIGN(4096) : AT(ADDR(.boot) - kernel_offset)
  {
    _boot = .;
    *(.boot)
    _eboot = .;
  }

  .bootdata ALIGN(4) : AT(ADDR(.bootdata) - kernel_offset)
  {
    _bootdata = .;
    *(.bootdata)
    _ebootdata = .;
  }

  .bootstack ALIGN(4096) : AT(ADDR(.bootstack) - kernel_offset)
  {
    _bootstack = .;
    . += boot_stack_size;
    _ebootstack = .;
  }

  .text ALIGN(4096) : AT(ADDR(.text) - kernel_offset)
  {
    _text = .;
    *(.text)
    _etext = .;
  }

  .rodata ALIGN(4) : AT(ADDR(.rodata) - kernel_offset)
  {
    _rodata = .;
    *(.rodata)
    _erodata = .;
  }

  .data ALIGN(4096) : AT(ADDR(.data) - kernel_offset)
  {
    _data = .;
    *(.data)
    _edata = .;
  }

  .bss ALIGN(4) : AT(ADDR(.bss) - kernel_offset)
  {
    _bss = .;
    *(.bss)
    _ebss = .;
  }

  _end = .;
}