Re: [rfc] Fix problem with (maybe) non-relocated .opd section on powerpc64-linux

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Daniel Jacobowitz wrote:
> On Thu, May 15, 2008 at 07:36:33PM +0200, Ulrich Weigand wrote:
> > Kernel modules generally have an opd section; as in other object files,
> > these will carry a R_PPC64_ADDR64 relocation pointing to .text + some
> > offset.  (In shared libraries we see a R_PPC_RELATIVE instead.)
> > 
> > That means my heuristics will probably go wrong when applied to an
> > object file (or kernel module).  When would that actually happen?
> 
> Generally, they are loaded with either add-symbol-file (by hand or
> autogenerated) specifying each section.  The KGDB guys also have a GDB
> patch to do it automatically.  That's one of my targetted applications
> of Python scripting.

Thinking about this, it seems this would mean that function descriptors
cannot work in kernel modules even today: add-symbol-file solely adds
an objfile (with obj_sections and so on); it does not modify the target
and its section table.  Right?

However, ppc64_linux_convert_from_func_ptr_addr *by design* only consults
the section table of the target -- this means it will never see those
extra symbol files anyway.

Am I missing something here?

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com