From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752076AbbJLO5J (ORCPT ); Mon, 12 Oct 2015 10:57:09 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:34170 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673AbbJLO5H (ORCPT ); Mon, 12 Oct 2015 10:57:07 -0400 X-Originating-IP: 50.43.35.112 Date: Mon, 12 Oct 2015 07:56:59 -0700 From: Josh Triplett To: Ingo Molnar Cc: Matt Fleming , Borislav Petkov , Stephen Smalley , x86@kernel.org, linux-kernel@vger.kernel.org, keescook@chromium.org, Thomas Gleixner , "H. Peter Anvin" , Peter Zijlstra Subject: Re: [PATCH v2] x86/mm: warn on W+x mappings Message-ID: <20151012145539.GA25937@x> References: <1443814185-21552-1-git-send-email-sds@tycho.nsa.gov> <20151003112701.GA4531@gmail.com> <5612CBE8.2010504@tycho.nsa.gov> <20151006073205.GA11115@gmail.com> <5613EAD5.2070405@tycho.nsa.gov> <20151012113605.GB7384@pd.tnic> <20151012141754.GA6621@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151012141754.GA6621@gmail.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 12, 2015 at 04:17:54PM +0200, Ingo Molnar wrote: > * Matt Fleming wrote: > > On Mon, 12 Oct, at 02:49:36PM, Ingo Molnar wrote: > > > So why not unmap them after bootup? Is there any reason to call into EFI code > > > while the system is up and running? > > > > That's where the runtime services code lives. So if you want things like EFI > > variables (used by the distro installer, among other things) you need to map the > > runtime regions. > > So EFI variables could be queried during bootup and saved on the Linux side. That wouldn't support writing to EFI variables. Or using the EFI capsule update system to update firmware. - Josh Triplett