On Mon, Jan 24, 2011 at 16:06, Stefano Bonifazi wrote: > I don't understand.. what is the difference between pie binary for pcc and > for your architecture?
as i said, i think this is all irrelevant to what you want to do. but since you asked and i feel like writing ... i have no idea what "pcc" is. there are really two stark differences between FDPIC ELF and a PIE ELF on say x86. since the data/text sections can be relocated independently of each other, the PIC cannot assume a fixed offset between its text and GOT. so every PLT entry is actually two sets of addresses -- the function address and the function's GOT address. the other big difference is that an FDPIC ELF app must first do a little relocation processing of itself as soon as it starts ... in order to do so, the kernel provides a loadmap (made up of multiple loadsegs) which describes the executable's PT_LOADs (the addr encoded in the program header and the addr the chunk was actually relocated to) as well as the (optional) executable's interpreter's PT_LOADs. > 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? but the PIE code still has fixed offsets between its text and its data. so FDPIC ELF is even more flexible than a PIE ELF. -mike
