From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATH V2 2/6] arm: mm: Introduce special ptes for LPAE Date: Wed, 27 Aug 2014 11:46:53 +0100 Message-ID: <20140827104653.GG6968@arm.com> References: <1408635812-31584-1-git-send-email-steve.capper@linaro.org> <1408635812-31584-3-git-send-email-steve.capper@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from fw-tnat.austin.arm.com ([217.140.110.23]:41655 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932539AbaH0Kr1 (ORCPT ); Wed, 27 Aug 2014 06:47:27 -0400 Content-Disposition: inline In-Reply-To: <1408635812-31584-3-git-send-email-steve.capper@linaro.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Steve Capper Cc: "linux-arm-kernel@lists.infradead.org" , "linux@arm.linux.org.uk" , "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , Will Deacon , "gary.robertson@linaro.org" , "christoffer.dall@linaro.org" , "peterz@infradead.org" , "anders.roxell@linaro.org" , "akpm@linux-foundation.org" , "dann.frazier@canonical.com" , Mark Rutland , "mgorman@suse.de" On Thu, Aug 21, 2014 at 04:43:28PM +0100, Steve Capper wrote: > We need a mechanism to tag ptes as being special, this indicates that > no attempt should be made to access the underlying struct page * > associated with the pte. This is used by the fast_gup when operating on > ptes as it has no means to access VMAs (that also contain this > information) locklessly. > > The L_PTE_SPECIAL bit is already allocated for LPAE, this patch modifies > pte_special and pte_mkspecial to make use of it, and defines > __HAVE_ARCH_PTE_SPECIAL. > > This patch also excludes special ptes from the icache/dcache sync logic. > > Signed-off-by: Steve Capper Reviewed-by: Catalin Marinas