From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754174AbaIXSoY (ORCPT ); Wed, 24 Sep 2014 14:44:24 -0400 Received: from terminus.zytor.com ([198.137.202.10]:34574 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753462AbaIXSoW (ORCPT ); Wed, 24 Sep 2014 14:44:22 -0400 Message-ID: <542310E3.90803@zytor.com> Date: Wed, 24 Sep 2014 11:43:47 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.0 MIME-Version: 1.0 To: "Bryan O'Donoghue" , mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, stable@vger.kernel.org, bp@alien8.de, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/platform] x86/intel/quark: Switch off CR4.PGE so TLB flush uses CR3 instead References: <1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie> <5422E8D0.5080705@zytor.com> <5422EA13.1080706@nexus-software.ie> <5422EC30.10206@nexus-software.ie> <54231088.8030000@zytor.com> In-Reply-To: <54231088.8030000@zytor.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/24/2014 11:42 AM, H. Peter Anvin wrote: > On 09/24/2014 09:07 AM, Bryan O'Donoghue wrote: >>> >>> So __flush_tlb_all(); will do nothing but that's OK since load_cr3() >>> already flushed the TLB - including any PTE with PGE set >> >> I take your point though. >> >> It's probably better to be explicit and do the whole >> >> if (quark) >> __flush_tlb(); >> else >> __flush_tlb_all(); >> >> So that we aren't relying on the side effects of the previous statement. >> > > Well, we need a comment at least. > And certainly we don't need an if/else as we can just do it. -hpa