Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752334Ab1BVRI7 (ORCPT ); Tue, 22 Feb 2011 12:08:59 -0500 Received: from anubis.se.axis.com ([195.60.68.12]:51229 "EHLO anubis.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750985Ab1BVRI5 (ORCPT ); Tue, 22 Feb 2011 12:08:57 -0500 Date: Tue, 22 Feb 2011 18:08:49 +0100 From: Jesper Nilsson To: Dmitry Torokhov Cc: Linus Torvalds , Benjamin Herrenschmidt , Rusty Russell , David Miller , "linux-kernel@vger.kernel.org" , "geert@linux-m68k.org" , "linux-m68k@vger.kernel.org" , "linux-arch@vger.kernel.org" , Mikael Starvik Subject: Re: [PATCH 1/3] module: deal with alignment issues in built-in module versions Message-ID: <20110222170849.GW13204@axis.com> References: <20110217.140119.39175251.davem@davemloft.net> <20110217221957.GA11244@dtor-ws.eng.vmware.com> <20110217.142320.102554706.davem@davemloft.net> <1298074455.2460.85.camel@pasglop> <87pqqmrq9q.fsf@rustcorp.com.au> <1298339909.8833.135.camel@pasglop> <20110222070240.GA21765@dtor-ws.eng.vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110222070240.GA21765@dtor-ws.eng.vmware.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3327 Lines: 89 On Tue, Feb 22, 2011 at 08:02:40AM +0100, Dmitry Torokhov wrote: > On Mon, Feb 21, 2011 at 06:03:16PM -0800, Linus Torvalds wrote: > > On Mon, Feb 21, 2011 at 5:58 PM, Benjamin Herrenschmidt > > wrote: > > > > > > The only sane thing I can see is make sure that such structures that > > > we put into sections "arrays" like that are naturally aligned with > > > padding. > > > > The sad part is, that assuming I read the gcc sources correctly (see > > the earlier emails where David pointed to it), that alignment is: > > - architecture-specific > > - depends on the size of the structure > > - seems to depend on the version of gcc itself. > > > > The _one_ safe case is likely to be "structure size is a power of > > two". And it does look like using a pointer is going to be safe, not > > only because the gcc auto-alignment only triggers for things like > > structs/unions/arrays, but because at least the x86 code only does it > > if the structure was bigger than the alignment size itself. > > > > So using pointer indirection is likely to be safe. It's still ugly and > > annoying as heck, though. > > > > Regardless the approach we'll take I think the following patch is also > needed (for cris architecture). I am not sure why __param section is > inly defined for one specific subarch That's probably just a legacy from when I combined the linkscripts for the two architectures. If I remember correctly, RODATA brings in RO_DATA_SECTION which in turn brings in __param and __modver for both architectures. CRISv32 then duplicates the __param stuff for some historical reason. > but I they need __param they'll > need __modev as well. True, at least until I've made sure that there isn't any underlying reason for CRISv32 to put __param in a different place... Acked-by: Jesper Nilsson > Thanks, > > Dmitry /Jesper > >From a567280f900c15891a55e7ea4e2919b38e1d1a01 Mon Sep 17 00:00:00 2001 > From: Dmitry Torokhov > Date: Thu, 17 Feb 2011 13:12:26 -0800 > Subject: [PATCH] cris: add missing __modver section > > Commit e94965ed5beb23c6fabf7ed31f625e66d7ff28de added a new __modver > section to store module version information for drivers built into the > kernel, but missed the fact that cris does some additional steps to > set up sections. > > Signed-off-by: Dmitry Torokhov > --- > arch/cris/kernel/vmlinux.lds.S | 4 ++++ > 1 files changed, 4 insertions(+), 0 deletions(-) > > diff --git a/arch/cris/kernel/vmlinux.lds.S b/arch/cris/kernel/vmlinux.lds.S > index 4422189..fae1b7b 100644 > --- a/arch/cris/kernel/vmlinux.lds.S > +++ b/arch/cris/kernel/vmlinux.lds.S > @@ -73,6 +73,10 @@ SECTIONS > .init.data : { INIT_DATA } > .init.setup : { INIT_SETUP(16) } > #ifdef CONFIG_ETRAX_ARCH_V32 > + __start___modver = .; > + __modver : { *(__modver) } > + __stop___modver = .; > + > __start___param = .; > __param : { *(__param) } > __stop___param = .; > -- > 1.7.3.2 /^JN - Jesper Nilsson -- Jesper Nilsson -- jesper.nilsson@axis.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/