From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936135AbXGTUgY (ORCPT ); Fri, 20 Jul 2007 16:36:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933811AbXGTUgO (ORCPT ); Fri, 20 Jul 2007 16:36:14 -0400 Received: from an-out-0708.google.com ([209.85.132.243]:11690 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933806AbXGTUgN (ORCPT ); Fri, 20 Jul 2007 16:36:13 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=V+LqCPO/IDKRsD3fD2fNtIXxH8Qm2ac65GZkY1iKDQs9Kna5KnxM4fDM+LcQtMxz78Hc5VSkVZJaDLs8K4+TFgkYYEdxvEFCHG5p/mB/EolwQL+snKcrPnOX6vyhBReK+16vyAV8ycJay5CWC5rpa2z9p3RDyu+BPjNAGh7nsGg= Message-ID: <8bd0f97a0707201336l6bed7c24i7014333ce356417f@mail.gmail.com> Date: Fri, 20 Jul 2007 16:36:12 -0400 From: "Mike Frysinger" To: "Mathieu Desnoyers" Subject: Re: blackfin - cmpxchg not atomic ? Cc: tonyko@lineo.ca, robin.getz@analog.com, linux-kernel@vger.kernel.org In-Reply-To: <20070720202807.GA15009@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070720202807.GA15009@Krystal> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 7/20/07, Mathieu Desnoyers wrote: > I am currently passing through each architectures adding a > cmpxchg_local() to each system.h, and I notice that you disable > interrupts in your cmpxchg() implementation, why are you doing so ? because Blackfin lacks any atomic instructions > Also, does you assembly stub _really_ modify memory atomically ? If yes, > then there should be no need for disabling interrupts. Else, I see a > major problem with SMP. that isnt the only problem with SMP on Blackfin > I also don't like the comment in asm-blackfin/atomic.h : > > * Generally we do not concern about SMP BFIN systems, so we don't have > * to deal with that. > > I have seen on the blackfin website that you actually sell a board with > SMP. Why aren't you caring about it ? just because a processor has more than one core does not make it SMP -mike