Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752684AbcDZR4Q (ORCPT ); Tue, 26 Apr 2016 13:56:16 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44426 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752654AbcDZR4M (ORCPT ); Tue, 26 Apr 2016 13:56:12 -0400 Date: Tue, 26 Apr 2016 10:54:40 -0700 From: tip-bot for Andy Lutomirski Message-ID: Cc: dvlasenk@redhat.com, linux-kernel@vger.kernel.org, bp@alien8.de, peterz@infradead.org, mroos@linux.ee, hpa@zytor.com, torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, luto@kernel.org, efault@gmx.de, luto@amacapital.net, brgerst@gmail.com Reply-To: luto@kernel.org, efault@gmx.de, mingo@kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, brgerst@gmail.com, luto@amacapital.net, linux-kernel@vger.kernel.org, dvlasenk@redhat.com, hpa@zytor.com, bp@alien8.de, mroos@linux.ee, peterz@infradead.org In-Reply-To: <59bd15f7f4b56b633a611b7f70876c6d2ad01a98.1461685884.git.luto@kernel.org> References: <59bd15f7f4b56b633a611b7f70876c6d2ad01a98.1461685884.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] Revert "x86/mm/32: Set NX in __supported_pte_mask before enabling paging" Git-Commit-ID: e16d8a6cbb499c5c8bfe9330d3351b649bded4af X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2574 Lines: 74 Commit-ID: e16d8a6cbb499c5c8bfe9330d3351b649bded4af Gitweb: http://git.kernel.org/tip/e16d8a6cbb499c5c8bfe9330d3351b649bded4af Author: Andy Lutomirski AuthorDate: Tue, 26 Apr 2016 08:52:44 -0700 Committer: Ingo Molnar CommitDate: Tue, 26 Apr 2016 19:52:57 +0200 Revert "x86/mm/32: Set NX in __supported_pte_mask before enabling paging" This reverts commit 320d25b6a05f8b73c23fc21025d2906ecdd2d4fc. This change was problematic for a couple of reasons: 1. It missed a some entry points (Xen things and 64-bit native). 2. The entry it changed can be executed more than once. This isn't really a problem, but it conflated per-cpu state setup and global state setup. 3. It broke 64-bit non-NX. 64-bit non-NX worked the other way around from 32-bit -- __supported_pte_mask had NX set initially and was *cleared* in x86_configure_nx. With the patch applied, it never got cleared. Reported-and-tested-by: Meelis Roos Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/59bd15f7f4b56b633a611b7f70876c6d2ad01a98.1461685884.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/head_32.S | 6 ------ arch/x86/mm/setup_nx.c | 5 +++-- 2 files changed, 3 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 54cdbd2..af11129 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -389,12 +389,6 @@ default_entry: /* Make changes effective */ wrmsr - /* - * And make sure that all the mappings we set up have NX set from - * the beginning. - */ - orl $(1 << (_PAGE_BIT_NX - 32)), pa(__supported_pte_mask + 4) - enable_paging: /* diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c index 8bea847..f65a33f 100644 --- a/arch/x86/mm/setup_nx.c +++ b/arch/x86/mm/setup_nx.c @@ -32,8 +32,9 @@ early_param("noexec", noexec_setup); void x86_configure_nx(void) { - /* If disable_nx is set, clear NX on all new mappings going forward. */ - if (disable_nx) + if (boot_cpu_has(X86_FEATURE_NX) && !disable_nx) + __supported_pte_mask |= _PAGE_NX; + else __supported_pte_mask &= ~_PAGE_NX; }