From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [PATCH 3/4] xen: arm: add barrier before sev in
	smp_spin_table_cpu_up
Date: Mon, 17 Mar 2014 14:18:30 +0000
Message-ID: <53270436.6010605@linaro.org>
References: <1395064315.18221.26.camel@kazak.uk.xensource.com>
	<1395064352-2128-3-git-send-email-ian.campbell@citrix.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <1395064352-2128-3-git-send-email-ian.campbell@citrix.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Ian Campbell <ian.campbell@citrix.com>
Cc: stefano.stabellini@eu.citrix.com, tim@xen.org, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

Hi Ian,

On 03/17/2014 01:52 PM, Ian Campbell wrote:
> This ensures that the writeq to the release address has occurred.
> 
> In reality there is a dsb() in the iounmap() (in the eventual write_pte()) but
> make it explicit.

There other place (see xen/arch/arm/platforms/exynos5.c) where we rely
on the dsb in write_pte. I think we should move the dsb in iounmap().

> 
> The ARMv8 ARM recommends that sev() is usually accompanied by a dsb(), the
> only other uses are in the v7 spinlock code which includes a dsb() already.

Would it be better to add dsb in the sev() macro?

Regards,

-- 
Julien Grall