From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751460AbeBVUhM (ORCPT ); Thu, 22 Feb 2018 15:37:12 -0500 Received: from mga09.intel.com ([134.134.136.24]:49853 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751411AbeBVUhH (ORCPT ); Thu, 22 Feb 2018 15:37:07 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,378,1515484800"; d="scan'208";a="19605599" Subject: [RFC][PATCH 04/10] x86/espfix: use kernel-default PTE mask To: linux-kernel@vger.kernel.org Cc: Dave Hansen , aarcange@redhat.com, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, jgross@suse.com, x86@kernel.org, namit@vmware.com From: Dave Hansen Date: Thu, 22 Feb 2018 12:36:58 -0800 References: <20180222203651.B776810C@viggo.jf.intel.com> In-Reply-To: <20180222203651.B776810C@viggo.jf.intel.com> Message-Id: <20180222203658.80705136@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen In creating its page tables, the espfix code masks its PGTABLE_PROT value with the supported mask: __supported_pte_mask. This ensures that unsupported bits are not set in the final PTE. But, it also sets _PAGE_GLOBAL which we do not want for PTE. Use __default_kernel_pte_mask instead which clears _PAGE_GLOBAL for PTI. Signed-off-by: Dave Hansen Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Kees Cook Cc: Hugh Dickins Cc: Juergen Gross Cc: x86@kernel.org Cc: Nadav Amit --- b/arch/x86/kernel/espfix_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN arch/x86/kernel/espfix_64.c~espfix-use-kern-defaults-not-supported arch/x86/kernel/espfix_64.c --- a/arch/x86/kernel/espfix_64.c~espfix-use-kern-defaults-not-supported 2018-02-22 12:36:19.217036552 -0800 +++ b/arch/x86/kernel/espfix_64.c 2018-02-22 12:36:19.221036552 -0800 @@ -167,7 +167,7 @@ void init_espfix_ap(int cpu) goto unlock_done; node = cpu_to_node(cpu); - ptemask = __supported_pte_mask; + ptemask = __default_kernel_pte_mask; pud_p = &espfix_pud_page[pud_index(addr)]; pud = *pud_p; _