From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: Re: [RFC PATCH 2/4] pio-mapping: Add ARM support for the PIO mapping API Date: Wed, 17 Feb 2010 20:04:46 +0000 Message-ID: <20100217200445.GA29249@flint.arm.linux.org.uk> References: <20100205163044.30827.10915.stgit@pc1117.cambridge.arm.com> <20100205163154.30827.6636.stgit@pc1117.cambridge.arm.com> <1265388234.14404.47.camel@mulgrave.site> <1265390403.7692.101.camel@pc1117.cambridge.arm.com> <1265391384.14404.53.camel@mulgrave.site> <1265645421.4020.119.camel@pc1117.cambridge.arm.com> <1265649274.6289.12.camel@mulgrave.site> <1265738604.8655.58.camel@pc1117.cambridge.arm.com> <1266397895.16346.267.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from caramon.arm.linux.org.uk ([78.32.30.218]:39136 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754805Ab0BQUI3 (ORCPT ); Wed, 17 Feb 2010 15:08:29 -0500 Content-Disposition: inline In-Reply-To: <1266397895.16346.267.camel@pasglop> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Benjamin Herrenschmidt Cc: Catalin Marinas , James Bottomley , linux-arch@vger.kernel.org On Wed, Feb 17, 2010 at 08:11:35PM +1100, Benjamin Herrenschmidt wrote: > In that case, I would recommend you look at how this is already dealt > with on existing archs such as powerpc, using PG_arch1 in struct page to > keep track of whether a given page is clean for execution and mapping > pages that aren't non-exec so the kernel gets a chance to clean them > once when execution happens. That would be fine if we weren't already using PG_arch_1 for delaying D-cache flushes for pages which aren't mapped, in the same way that Sparc64 does. That doesn't cover this case though - the problem is not I/D cache coherency - the problem has manifested itself as data corruption when userspace reads the page. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: