From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932342Ab2K1UiK (ORCPT ); Wed, 28 Nov 2012 15:38:10 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:60429 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932085Ab2K1UiI (ORCPT ); Wed, 28 Nov 2012 15:38:08 -0500 MIME-Version: 1.0 In-Reply-To: <20121128190902.GS21266@phenom.dumpdata.com> References: <1353123563-3103-1-git-send-email-yinghai@kernel.org> <1353123563-3103-35-git-send-email-yinghai@kernel.org> <20121128190902.GS21266@phenom.dumpdata.com> Date: Wed, 28 Nov 2012 12:38:06 -0800 X-Google-Sender-Auth: w6POzqBpLXmLNXKz3vJH-AGCFGI Message-ID: Subject: Re: [PATCH v8 34/46] x86, mm: Add check before clear pte above max_low_pfn on 32bit From: Yinghai Lu To: Konrad Rzeszutek Wilk Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jacob Shin , Andrew Morton , Stefano Stabellini , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 28, 2012 at 11:09 AM, Konrad Rzeszutek Wilk wrote: >> /* >> * Remove any mappings which extend past the end of physical >> - * memory from the boot time page table: >> + * memory from the boot time page table. >> + * In virtual address space, we should have at least two pages >> + * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END >> + * definition. And max_low_pfn is set to VMALLOC_END physical >> + * address. If initial memory mapping is doing right job, we >> + * should have pte used near max_low_pfn or one pmd is not present. > > 'have pte used near' ? > > Do you mean we should have an used PTE near max_low_pfn and one > empty PMD? > ==> * we should have used PTE to map address near max_low_pfn or * one empty PMD