From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032821AbeBONZ5 (ORCPT ); Thu, 15 Feb 2018 08:25:57 -0500 Received: from mga01.intel.com ([192.55.52.88]:55155 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032283AbeBONZU (ORCPT ); Thu, 15 Feb 2018 08:25:20 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,517,1511856000"; d="scan'208";a="17900715" Subject: [PATCH 0/3] Use global pages with PTI To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Dave Hansen , luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, jgross@suse.com, x86@kernel.org From: Dave Hansen Date: Thu, 15 Feb 2018 05:20:53 -0800 Message-Id: <20180215132053.6C9B48C8@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The later verions of the KAISER pathces (pre-PTI) allowed the user/kernel shared areas to be GLOBAL. The thought was that this would reduce the TLB overhead of keeping two copies of these mappings. During the switch over to PTI, we seem to have lost our ability to have GLOBAL mappings. This adds them back. Did we have some reason for leaving out global pages entirely? We _should_ have all the TLB flushing mechanics in place to handle these already since all of our kernel mapping changes have to know how to flush global pages regardless. Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Kees Cook Cc: Hugh Dickins Cc: Juergen Gross Cc: x86@kernel.org