Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933453AbZJOQjU (ORCPT ); Thu, 15 Oct 2009 12:39:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933319AbZJOQjU (ORCPT ); Thu, 15 Oct 2009 12:39:20 -0400 Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:55433 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932130AbZJOQjT (ORCPT ); Thu, 15 Oct 2009 12:39:19 -0400 Date: Thu, 15 Oct 2009 12:37:20 -0400 (EDT) From: Tim Abbott X-X-Sender: tabbott@dr-wily.mit.edu To: Benjamin Herrenschmidt cc: sam@ravnborg.org, linuxppc-dev@lists.ozlabs.org, Linus Torvalds , Andrew Morton , "linux-kernel@vger.kernel.org" Subject: Re: powerpc problem with .data.page_aligned -> __page_aligned_data conversion In-Reply-To: <1255584772.2347.86.camel@pasglop> Message-ID: References: <1255584772.2347.86.camel@pasglop> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Flag: NO X-Spam-Score: 0.00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1254 Lines: 30 On Thu, 15 Oct 2009, Benjamin Herrenschmidt wrote: > For some weird reason, our gcc until 4.3 (fixed in 4.3) had the weird > idea that the alignment attribute should not be allowed to force an > alignment greater than 32k. If attempted, it would warn -and- crop the > alignment to 32k. [...] > This has a few issues for us: > > - The patch that converted bits of powerpc to the new macro break since > it now hits that bug Hi Ben, Just to make sure I understand the nature of the problem, is the current breakage that gcc < 4.3 will _warn_ on any compilation units on ppc64 that use __page_aligned data, or something worse? The cropping is clearly a potential problem, but I read the rest of your email as saying that the cropping of the alignment isn't actually a problem with the current kernel because the kernel is currently only using the macro with things whose size is divisible by PAGE_SIZE. However, I am not sure how to reconcile that with using the word "break" above... -Tim Abbott -- 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/