I am working on a research project where I need to compile a program with multiple sections. These sections need to be loaded with different PIE offsets. I am wondering how I can do it in GCC.

See below for a MWE. In my program there is a .my_region section and other sections (.text, .bss, …). I want to make sure that all sections can be loaded at random addresses. Also, I want to make sure the relative offset between .my_region and other sections are different.

For example, this is what I am looking for:

I think technically this can be implemented either using GOT or the .rela.dyn section. However, I don’t know how to pass arguments to GCC and ld to achieve this.

Minimal working example (MWE):

a.c:

int normal_array[10];

int my_array[10] __attribute__(( section(".my_data") ));

void start() {
    normal_array[0] = 0;
    my_array[1] = 1;
    asm volatile("hlt");
}

l.lds:

ENTRY(start)

MEMORY
{
  all (rwxai) : ORIGIN = 3M, LENGTH = 1M
  my_region (rwxai) : ORIGIN = 5M, LENGTH = 1M
}

SECTIONS
{
  .my_data : {
    *(.my_data)
  } >my_region =0x9090
}

Makefile:

CFLAGS = -fPIE
ASFLAGS = -fPIE

# I am on 64-bit x86 Linux platform.
a: a.o l.lds
    ld -pie --dynamic-linker=/lib64/ld-linux-x86-64.so.2 -T l.lds -o $@ a.o

clean:
    rm -f *.o a

Use make a to compile. Use gdb a to debug (set a break at start and then step through each instruction).