Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752677Ab1CODIV (ORCPT ); Mon, 14 Mar 2011 23:08:21 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:62443 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750807Ab1CODIT convert rfc822-to-8bit (ORCPT ); Mon, 14 Mar 2011 23:08:19 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=yGeiOTjAMyUBCvYS8z4M1KzfIUZ8CXRZp4IcF6pY3VoCGmBs2IDc6ogtJPYBgDuFP8 ZgQiTvKrUYF9m4ZLesLNd6HG5PAG1uG9Rv21zIxtdvg5x0sKgWFffiYYhk76GQzWHlCM /HQNoWU1Z2OpyDphc4acCQMwXirb5xzjSoVHs= MIME-Version: 1.0 In-Reply-To: <20110314104038.GB26085@n2100.arm.linux.org.uk> References: <1300098516-1601-1-git-send-email-ratbert.chuang@gmail.com> <20110314104038.GB26085@n2100.arm.linux.org.uk> From: Po-Yu Chuang Date: Tue, 15 Mar 2011 11:07:58 +0800 Message-ID: Subject: Re: [PATCH] arm: cmpxchg syscall should data abort if page not write or not young To: Russell King - ARM Linux Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tony@atomide.com, nicolas.pitre@linaro.org, joe@perches.com, Po-Yu Chuang Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 916 Lines: 26 Dear Russell King, On Mon, Mar 14, 2011 at 6:40 PM, Russell King - ARM Linux wrote: > On Mon, Mar 14, 2011 at 06:28:36PM +0800, Po-Yu Chuang wrote: >> From: Po-Yu Chuang >> >> If the page to cmpxchg is user mode read only (not write) >> or invalid (not young), we should simulate a data abort first. > > No.  If it is not young then it should be made young.  Age is an effect > of accesses.  It's not a permission. OK, I will rethink about the not young part. Thanks for your pointer. I will resubmit a v2 which contains only the read only check. It fixes a problem we met with futex. best regards, Po-Yu Chuang -- 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/