Re: [Qemu-devel] Re: [RFC/PATCH] elfload: add FDPIC support

[Stefano Bonifazi]

On 01/24/2011 08:11 PM, Mike Frysinger wrote:
> On Mon, Jan 24, 2011 at 08:34, Stefano Bonifazi wrote:
> > Is FDPIC something different than simply PIC code (position independent
> > code)?
> FDPIC ELF is the ELF PIE format used on NOMMU systems so that both the
> text and data regions may be located anywhere.  it is the only ELF
> format supported under NOMMU systems.
>
> > I am also trying to fight with the problem of changing the starting address
> > of target code for qemu-user, and I was just moving into the option of using
> > PIC target code .. but the original qemu-user load_elf_binary does not work
> > on them.. and I was just about to try to edit it..
> i dont believe my patch accomplishes that in any way.  i will need to
> force all files to be loaded at a higher address than zero for the
> Blackfin arch (as the first ~4KiB is reserved for the ABI), but that
> is independent of FDPIC ELF support.
> -mike
I don't understand.. what is the difference between pie binary for pcc 
and for your architecture?
As far as I understood pie code is independent from addresses, so it 
should not care if the OS running them would have an mmu at all.. it 
should be just the task of the dynamic linker to relocate it properly, 
am I wrong?
Thank you!
Regards,
Stefano B.