From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id 7F46D6B0009 for ; Mon, 2 Apr 2018 13:52:36 -0400 (EDT) Received: by mail-io0-f199.google.com with SMTP id r19so1660443iod.7 for ; Mon, 02 Apr 2018 10:52:36 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id 191sor412069ioe.271.2018.04.02.10.52.35 for (Google Transport Security); Mon, 02 Apr 2018 10:52:35 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20180402172701.5D4CA7DD@viggo.jf.intel.com> References: <20180402172700.65CAE838@viggo.jf.intel.com> <20180402172701.5D4CA7DD@viggo.jf.intel.com> From: Linus Torvalds Date: Mon, 2 Apr 2018 10:52:34 -0700 Message-ID: Subject: Re: [PATCH 01/11] x86/mm: factor out pageattr _PAGE_GLOBAL setting Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Linux Kernel Mailing List , linux-mm , Andrea Arcangeli , Andrew Lutomirski , Kees Cook , Hugh Dickins , =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , the arch/x86 maintainers , namit@vmware.com On Mon, Apr 2, 2018 at 10:27 AM, Dave Hansen wrote: > > Aside: _PAGE_GLOBAL is ignored when CR4.PGE=1, so why do we > even go to the trouble of filtering it anywhere? I'm assuming this is a typo, and you mean "when CR4.PGE=0". The question you raise may be valid, but within the particular context of *this* patch it is not. In the context of this particular patch, the issue is that we use _PAGE_GLOBAL as _PAGE_BIT_PROTNONE when the present bit isn't set. Linus