From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S978711AbdDXWKA (ORCPT ); Mon, 24 Apr 2017 18:10:00 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:58404 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S977769AbdDXWJw (ORCPT ); Mon, 24 Apr 2017 18:09:52 -0400 Date: Mon, 24 Apr 2017 18:09:48 -0400 (EDT) Message-Id: <20170424.180948.1311847745777709716.davem@davemloft.net> To: glaubitz@physik.fu-berlin.de Cc: kirill@shutemov.name, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, ak@linux.intel.com, dave.hansen@intel.com, luto@amacapital.net, mhocko@suse.com, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: Re: Question on the five-level page table support patches From: David Miller In-Reply-To: References: <030ea57b-5f6c-13d8-02f7-b245a754a87d@physik.fu-berlin.de> <20170424161959.c5ba2nhnxyy57wxe@node.shutemov.name> X-Mailer: Mew version 6.7 on Emacs 25.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 24 Apr 2017 14:28:28 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: John Paul Adrian Glaubitz Date: Mon, 24 Apr 2017 22:37:40 +0200 > Would be really nice to able to have a canonical solution for this issue, > it's been biting us on SPARC for quite a while now due to the fact that > virtual address space has been 52 bits on SPARC for a while now. It's going to break again with things like ADI which encode protection keys in the high bits of the 64-bit virtual address. Reallly, it would be nice if these tags were instead encoded in the low bits of suitably aligned memory allocations but I am sure it's to late to do that now.