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Re: Bug#539378: [hppa]: fails to load nfs module: Global Offset Table



> On Fri, Jul 31, 2009 at 5:09 PM, Helge Deller<deller@gmx.de> wrote:
> > On 07/31/2009 09:03 PM, John David Anglin wrote:
> >>>
> >>> Only 32-bit targets have the 14-bit signed immediate offset (0x3fff),
> >>> which becomes a 13-bit limit when loading positive offsets e.g.
> >>> +0x1fff or 1023 GOT slots.
> >>
> >> Can't we offset the table and double the number of entries?
> >
> > Dave,
> > Can you explain this idea a little more?
> 
> I would also like a little more details.
> 
> However, this is similar to the DT_PLTGOT issue in dynamic libraries.
> The value chosen for %dp is arbitrary, and if we made it point into
> the middle of the GOT table, then you would reference the GOT using
> both positive and negative offsets.
> 
> For example, this code:
> fdesc->gp = (Elf_Addr)me->module_core + me->arch.got_offset;
> 
> Arbitrary chooses the module %dp to point at the start of got_offset,
> why not make that got_offset + <half way>.

I don't have more details...  The idea is as Carlos outlined.  There's
code in the binutils elf32-hppa.c and elf64-hppa.c files to implement
the above for dynamic libraries.  That's what made me think of it.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6602)


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