Date: Thu, 9 Sep 2004 05:12:08 -0400
From: Jakub Jelinek <jakub@redhat.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>,
       linuxppc64-dev <linuxppc64-dev@lists.linuxppc.org>,
       Ulrich Drepper <drepper@redhat.com>
Subject: Re: vDSO for ppc64 : Preliminary release #3
Message-ID: <20040909091208.GY31909@devserv.devel.redhat.com>
Reply-To: Jakub Jelinek <jakub@redhat.com>
References: <1094719382.2543.62.camel@gaston>
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On Thu, Sep 09, 2004 at 06:43:03PM +1000, Benjamin Herrenschmidt wrote:
>  - The current glibc code for dealing with vdso's is not completely
> appropriate for ppc64 in particular since we do need relocations to be
> performed on the OPD section (thanks mprotect + COW, it actually works)
> if the library is ever mapped at a differnet address than it's native
> 0x100000 (via the new phdr for example).
> The current glibc code forces l_relocated to 1 for all vdso's (which is
> fine for archs without need to relocate function descriptors).

That is on purpose, even if vDSO location is randomized (e.g. on IA-32),
no relocations should happen, so that the vDSO can be shared (unless
written into by the debugger, that is).  ld.so knows how to deal with
.dynamic section relocation of vDSOs.

	Jakub
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