From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 4802E6B0038 for ; Wed, 1 Nov 2017 17:24:40 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id z11so3182068pfk.23 for ; Wed, 01 Nov 2017 14:24:40 -0700 (PDT) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id b5si1884925pgr.120.2017.11.01.14.24.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 01 Nov 2017 14:24:39 -0700 (PDT) Received: from mail-io0-f182.google.com (mail-io0-f182.google.com [209.85.223.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DFA6D21959 for ; Wed, 1 Nov 2017 21:24:38 +0000 (UTC) Received: by mail-io0-f182.google.com with SMTP id 101so9251939ioj.3 for ; Wed, 01 Nov 2017 14:24:38 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20171031223146.6B47C861@viggo.jf.intel.com> <20171031223150.AB41C68F@viggo.jf.intel.com> From: Andy Lutomirski Date: Wed, 1 Nov 2017 14:24:17 -0700 Message-ID: Subject: Re: [PATCH 02/23] x86, kaiser: do not set _PAGE_USER for init_mm page tables Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner Cc: Dave Hansen , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , moritz.lipp@iaik.tugraz.at, Daniel Gruss , michael.schwarz@iaik.tugraz.at, Andrew Lutomirski , Linus Torvalds , Kees Cook , Hugh Dickins , X86 ML On Wed, Nov 1, 2017 at 2:11 PM, Thomas Gleixner wrote: > On Tue, 31 Oct 2017, Dave Hansen wrote: > >> >> init_mm is for kernel-exclusive use. If someone is allocating page >> tables in it, do not set _PAGE_USER on them. This ensures that >> we do *not* set NX on these page tables in the KAISER code. > > This changelog is confusing at best. > > Why is this a kaiser issue? Nothing should ever create _PAGE_USER entries > in init_mm, right? The vsyscall page is _PAGE_USER and lives in init_mm via the fixmap. --Andy -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org