From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753986Ab3J2KND (ORCPT ); Tue, 29 Oct 2013 06:13:03 -0400 Received: from mail-ee0-f51.google.com ([74.125.83.51]:48786 "EHLO mail-ee0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751648Ab3J2KNB (ORCPT ); Tue, 29 Oct 2013 06:13:01 -0400 Date: Tue, 29 Oct 2013 11:12:57 +0100 From: Ingo Molnar To: Jan Beulich Cc: Peter Zijlstra , mingo@elte.hu, tglx@linutronix.de, Andrew Morton , Linus Torvalds , arjan@linux.intel.com, linux@roeck-us.net, linux-kernel@vger.kernel.org, hpa@zytor.com Subject: Re: [PATCH 1/2] x86: unify copy_from_user() size checking Message-ID: <20131029101257.GA25953@gmail.com> References: <5265056D02000078000FC4F3@nat28.tlf.novell.com> <20131026103109.GC14949@gmail.com> <526F914A02000078000FD806@nat28.tlf.novell.com> <20131029095408.GB25306@gmail.com> <526F971F02000078000FD841@nat28.tlf.novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <526F971F02000078000FD841@nat28.tlf.novell.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jan Beulich wrote: > >>> On 29.10.13 at 10:54, Ingo Molnar wrote: > > > * Jan Beulich wrote: > > > >> >>> On 26.10.13 at 12:31, Ingo Molnar wrote: > >> > * Jan Beulich wrote: > >> >> I'd like to point out though that with __compiletime_object_size() > >> >> being restricted to gcc before 4.6, the whole construct is going to > >> >> become more and more pointless going forward. I would question > >> >> however that commit 2fb0815c9ee6b9ac50e15dd8360ec76d9fa46a2 ("gcc4: > >> >> disable __compiletime_object_size for GCC 4.6+") was really necessary, > >> >> and instead this should have been dealt with as is done here from the > >> >> beginning. > >> > > >> > Can we now revert 2fb0815c9ee6? > >> > >> Actually I'm afraid parisc would first need to follow the changes > >> done on x86 here, or else they'd run into (compile time) issues > >> (s390 and tile only emit warnings, i.e. would at worst suffer > >> cosmetically unless subtrees putting -Werror in place are > >> affected). > > > > Given how trivial __compiletime_object_size() is, we could replicate > > a (differently named) copy of that in x86 uaccess.h? > > I would never have dared to suggest something like that... > > But if you're fine with that, I can certainly do so. I'd then even > wonder whether we shouldn't re-use the same name, > #undef-ing the one we got from compiler*.h - after all the > goal would be for compiler-gcc4.h to change in exactly that way. Yeah, I think that would work. > > This is something that would be pretty platform dependent > > anyway. > > Why do you think so? That's entirely a compiler construct. Yeah, what I mean is that the progress of kernel support here is done on a per platform manner anyway, the 'generic' piece in compiler.h and compiler-gcc4.h is tiny and more of a hindrance than a useful generalization/sharing of code... Thanks, Ingo