From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760574AbZLKKiH (ORCPT ); Fri, 11 Dec 2009 05:38:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756700AbZLKKiE (ORCPT ); Fri, 11 Dec 2009 05:38:04 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:57893 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756610AbZLKKiD (ORCPT ); Fri, 11 Dec 2009 05:38:03 -0500 Date: Fri, 11 Dec 2009 02:38:08 -0800 (PST) Message-Id: <20091211.023808.233094506.davem@davemloft.net> To: mingo@elte.hu Cc: jamie.iles@picochip.com, linux-kernel@vger.kernel.org, linux@arm.linux.org.uk, peterz@infradead.org Subject: Re: [PATCH 1/2] perf tools: allow building for ARM From: David Miller In-Reply-To: <20091211102316.GB16882@elte.hu> References: <1260523260-15694-1-git-send-email-jamie.iles@picochip.com> <20091211102316.GB16882@elte.hu> X-Mailer: Mew version 6.2 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ingo Molnar Date: Fri, 11 Dec 2009 11:23:16 +0100 > > * Jamie Iles wrote: > >> +#ifdef __arm__ >> +#include "../../arch/arm/include/asm/unistd.h" >> +#define rmb() asm volatile("":::"memory") >> +#define cpu_relax() asm volatile("":::"memory") >> +#endif > > cpu_relax() looks fine, but rmb() seems not to match the one that can be > found in arch/arm/: I think he did it this way so it can compile in the meantime, and that doing it right requires runtime cpu detection to select which barrier instruction is even available on the current ARM cpu.