On Mon, Dec 17, 2001 at 06:52:15PM +0100, Jakub Jelinek wrote: > On Mon, Dec 17, 2001 at 09:10:32AM -0800, H . J . Lu wrote: > > On Mon, Dec 17, 2001 at 12:36:31PM +0100, Jakub Jelinek wrote: > > > > > instead (well, best would be if somebody ported prelink to mips; > > > I'll try to answer any questions and help). > > > > Do you have some documentations how prelink works? > > So far not too much. Some info is in prelink(8) man page, some info > was posted to binutils mailing list. I have prelink-20011010.tar.bz2. Is that current? > > > > I skipped mips because it is way too different from how any other ELF > > > architecture works (e.g. using a single dynamic reloc type for everything > > > with various meanings, etc.) and I have no access to it. > > > > That is what I am afraid of. The MIPS ABI supports "quickstart". > > I know, but from what I understood, quickstart e.g. just assumes there won't > be conflicts and if there are, their handling is very costly (their > conflicts are just symbol indices which need to be checked out). > prelink conflicts are ElfW(Rela) relocs against r_symndx 0. > > To port prelink to a new architecture, you need basically: > 1) determine what you need to do with relocations and special CPU sections > when relocating a shared library from one address to another one > (e.g. you can link a shared libs once at VMA 0, once at VMA 0xdeadb000 > and see what changed) - these are *_adjust_* functions > 2) write routines which apply relocs (*_prelink_rel*) > 3) write routines which create conflict relocs > 4) as MIPS is rel, it needs to be figured out when it is needed to convert > from Rel to Rela (in i386/arm case in most cases it can be avoided, > the only relocs which require it are (on i386): R_386_32 with nonzero > addend (otherwise R_386_GLOB_DAT does exactly the same thing) and > R_386_PC32). This is needed, because otherwise the information about the > original addend is lost when the final relocated value is stored at > r_offset address. Original addend is needed, if prelink cannot be used, > during dynamic linking. If MIPS has some place where it stashes this > for Quickstart, then it could be reused, otherwise I'm afraid REL->RELA will > happen more often on MIPS than on IA-32/ARM. > 5) write routines which apply relocs to a buffer or apply a conflict > to a buffer (these are used when doing comparisons on relocated content) > As I unsterstand, MIPS only has R_MIPS_REL32 for GOT in DSO and EXE. Do you have any suggestions? H.J.
