From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758864AbcAUFeL (ORCPT ); Thu, 21 Jan 2016 00:34:11 -0500 Received: from ozlabs.org ([103.22.144.67]:48271 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752436AbcAUFeI (ORCPT ); Thu, 21 Jan 2016 00:34:08 -0500 X-powerpc-patch-notification: thanks X-powerpc-patch-commit: c153693d7eb9eeb28478aa2deaaf0b4e7b5ff5e9 In-Reply-To: <1453077867-23873-1-git-send-email-mpe@ellerman.id.au> To: Michael Ellerman , From: Michael Ellerman Cc: amodra@gmail.com, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org, quentin.casasnovas@oracle.com, paul.gortmaker@windriver.com, Anton Blanchard Subject: Re: powerpc: Simplify module TOC handling Message-Id: <20160121053407.A6CEB140BF6@ozlabs.org> Date: Thu, 21 Jan 2016 16:34:07 +1100 (AEDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2016-18-01 at 00:44:27 UTC, Michael Ellerman wrote: > From: Alan Modra > > PowerPC64 uses the symbol .TOC. much as other targets use > _GLOBAL_OFFSET_TABLE_. It identifies the value of the GOT pointer (or in > powerpc parlance, the TOC pointer). Global offset tables are generally > local to an executable or shared library, or in the kernel, module. Thus > it does not make sense for a module to resolve a relocation against > .TOC. to the kernel's .TOC. value. A module has its own .TOC., and > indeed the powerpc64 module relocation processing ignores the kernel > value of .TOC. and instead calculates a module-local value. > > This patch removes code involved in exporting the kernel .TOC., tweaks > modpost to ignore an undefined .TOC., and the module loader to twiddle > the section symbol so that .TOC. isn't seen as undefined. > > Note that if the kernel was compiled with -msingle-pic-base then ELFv2 > would not have function global entry code setting up r2. In that case > the module call stubs would need to be modified to set up r2 using the > kernel .TOC. value, requiring some of this code to be reinstated. > > mpe: Furthermore a change in binutils master (not yet released) causes > the current way we handle the TOC to no longer work when building with > MODVERSIONS=y and RELOCATABLE=n. The symptom is that modules can not be > loaded due to there being no version found for TOC. > > Cc: stable@vger.kernel.org # 3.16+ > Signed-off-by: Alan Modra > Signed-off-by: Michael Ellerman Applied to powerpc fixes. https://git.kernel.org/powerpc/c/c153693d7eb9eeb28478aa2dea cheers