Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763566AbXHJJIv (ORCPT ); Fri, 10 Aug 2007 05:08:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753942AbXHJJIg (ORCPT ); Fri, 10 Aug 2007 05:08:36 -0400 Received: from cantor2.suse.de ([195.135.220.15]:56256 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752842AbXHJJIf (ORCPT ); Fri, 10 Aug 2007 05:08:35 -0400 From: Andi Kleen Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg) To: Herbert Xu Subject: Re: [PATCH 1/24] make atomic_read() behave consistently on alpha Date: Fri, 10 Aug 2007 11:08:20 +0200 User-Agent: KMail/1.9.6 Cc: paulmck@linux.vnet.ibm.com, csnook@redhat.com, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org, netdev@vger.kernel.org, akpm@linux-foundation.org, heiko.carstens@de.ibm.com, davem@davemloft.net, schwidefsky@de.ibm.com, wensong@linux-vs.org, horms@verge.net.au, wjiang@resilience.com, cfriesen@nortel.com, zlynx@acm.org, rpjday@mindspring.com, jesper.juhl@gmail.com References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200708101108.20897.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1092 Lines: 24 On Friday 10 August 2007 10:21:46 Herbert Xu wrote: > Paul E. McKenney wrote: > > > > The compiler is within its rights to read a 32-bit quantity 16 bits at > > at time, even on a 32-bit machine. I would be glad to help pummel any > > compiler writer that pulls such a dirty trick, but the C standard really > > does permit this. > > Code all over the kernel assumes that 32-bit reads/writes > are atomic so while such a compiler might be legal it certainly > can't compile Linux. Yes, the kernel requirements are much stricter than ISO-C. And besides it is a heavy user of C extensions anyways. On the other hand some of the C99 extensions are not allowed. And then there is sparse, which enforces a language which sometimes is quite far from standard C. You could say it is written in Linux-C, not ISO C. -Andi - 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/