From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936142AbdIYTmH (ORCPT ); Mon, 25 Sep 2017 15:42:07 -0400 Received: from gate.crashing.org ([63.228.1.57]:54842 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934967AbdIYTmF (ORCPT ); Mon, 25 Sep 2017 15:42:05 -0400 Date: Mon, 25 Sep 2017 14:41:31 -0500 From: Segher Boessenkool To: David Laight Cc: Kees Cook , Linux-MM , LKML , Jinbum Park , Andrew Morton , "linuxppc-dev@lists.ozlabs.org" Subject: Re: [PATCH] mm: fix RODATA_TEST failure "rodata_test: test data was not read only" Message-ID: <20170925194130.GV8421@gate.crashing.org> References: <20170921093729.1080368AC1@po15668-vm-win7.idsi0.si.c-s.fr> <20170925073721.GM8421@gate.crashing.org> <063D6719AE5E284EB5DD2968C1650D6DD007F58B@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DD007F58B@AcuExch.aculab.com> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 25, 2017 at 04:01:55PM +0000, David Laight wrote: > From: Segher Boessenkool > > The compiler puts this item in .sdata, for 32-bit. There is no .srodata, > > so if it wants to use a small data section, it must use .sdata . > > > > Non-external, non-referenced symbols are not put in .sdata, that is the > > difference you see with the "static". > > > > I don't think there is a bug here. If you think there is, please open > > a GCC bug. > > The .sxxx sections are for 'small' data that can be accessed (typically) > using small offsets from a global register. > This means that all sections must be adjacent in the image. > So you can't really have readonly small data. > > My guess is that the linker script is putting .srodata in with .sdata. .srodata does not *exist* (in the ABI). Segher