Re: [PATCH] dl: Use "adr" assembler command to get proper load address

["H.J. Lu" <hjl.tools@gmail.com>]

On Thu, Oct 7, 2021 at 8:57 AM Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>
> The 10/07/2021 07:29, H.J. Lu via Libc-alpha wrote:
> > On Thu, Oct 7, 2021 at 7:18 AM Adhemerval Zanella via Libc-alpha
> > <libc-alpha@sourceware.org> wrote:
> > > On 07/10/2021 07:00, Lukasz Majewski wrote:
> > > > On Thu, 7 Oct 2021 11:19:26 +0200
> > > > Lukasz Majewski <lukma@denx.de> wrote:
> > > > And indeed it is the case. Yocto/OE by default perform prelinking (use
> > > > prelink program) to speedup start time of dynamic program.
> > > >
> > > > The prelink [1] itself assigns some virtual addresses to all required
> > > > shared objects (in our case for /sbin/init), so no clashes are
> > > > encountered.
> > > >
> > > > And using prelink is a _default_ behaviour in Yocto/OE poky distro.
> > >
> > > Does it work without prelink? Also, does it fail with prelink in real
> > > hardware?
> > >
> > > It indeed might be a prelink issue in fact.
> >
> > This will fail everywhere if prelink is used.
>
> i thought the point of prelinking is that the vaddr in
> the elf image is the runtime address so you don't have
> to process relative relocs or adjust pointers in the
> dynamic array with += l_addr at all (and then l_addr
> does not have to be correct, ld.so would still work).
>
> but here ld.so is loaded to some random offset on top
> of the static prelink offset. is this expected?
> does it make sense to prelink ld.so this way?

ld.so is loaded by the kernel.  It makes no sense to
prelink ld.so.

-- 
H.J.