From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1163294AbXD1SSg (ORCPT ); Sat, 28 Apr 2007 14:18:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1163465AbXD1SSa (ORCPT ); Sat, 28 Apr 2007 14:18:30 -0400 Received: from smtp-out.google.com ([216.239.45.13]:38270 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1163297AbXD1SSK (ORCPT ); Sat, 28 Apr 2007 14:18:10 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:from:message-id:to:cc:subject:date:mime-version: content-type:content-transfer-encoding:x-mailer:in-reply-to:x-mimeole:thread-index; b=Z+uhThAWvguY5xvhUT0pGAeylv1yzqma47ILt4uzZOlgjdKbpj0It1md5oEEuD+tI dFkhBJJ9FuiZPTdW7RgiA== From: Rohit Seth Message-Id: <200704281817.l3SIHu0P001764@smtp.corp.google.com> To: "'Hugh Dickins'" Cc: "'Nick Piggin'" , "'Mike Stroyan'" , "'Andrew Morton'" , "'Luck, Tony'" , , Subject: RE: Fw: [PATCH] ia64: race flushing icache in do_no_page path Date: Sat, 28 Apr 2007 11:17:45 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.6353 In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 Thread-Index: AceJVvEwu7f6EhlxTLuPm01ZMOb+mwAaO6hg Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Hugh, -----Original Message----- From: Hugh Dickins [mailto:hugh@veritas.com] Sent: Friday, April 27, 2007 10:34 PM To: Rohit Seth Cc: Nick Piggin; Mike Stroyan; Andrew Morton; Luck, Tony; linux-ia64@vger.kernel.org; linux-kernel@vger.kernel.org Subject: Re: Fw: [PATCH] ia64: race flushing icache in do_no_page path On Fri, 27 Apr 2007, Rohit Seth wrote: > lazy_mmu_prot_update was added specifically for notifying change in > protection. So, in a way it is closer to update_mmu_cache (Which is > for change in mappings itself). Though for ia64 implementation, this > ends up flushing the icaches when needed. >The ia64 implementation is the only one which has any use for it, Even Itanium didn't need it for almost 5 years :) Though I think archs that have incoherent I & D caches could be (theoritically) exposed to same (original) mprotect code path bug that triggered this API. >and >it's only interested when it's executable i.e. "lazy_mmu_prot_update" >is a name concealing some overdesign. You are right that ia64 is only interested in whne the execute permissions kick in (and FWIW ia64 used to use update_mmu_cache API to do what it is now doing lazy_mmu_prot_update). Though the idea was to design an API that any arch can use to know when ever there is change in protections on a mapping. Cheers, -rohit