From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06770C2BA83 for ; Tue, 16 Mar 2021 15:13:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3B5D650D4 for ; Tue, 16 Mar 2021 15:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238078AbhCPPNM (ORCPT ); Tue, 16 Mar 2021 11:13:12 -0400 Received: from mga09.intel.com ([134.134.136.24]:13631 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235132AbhCPPLd (ORCPT ); Tue, 16 Mar 2021 11:11:33 -0400 IronPort-SDR: QLXdO5p9quwM+QD2a0ZRfPbK/mhS9WrqsGMBo5hCohaHV0zflASEpqDVK4zBGwWAr/KUYiXvX7 wdRWUuolFvOA== X-IronPort-AV: E=McAfee;i="6000,8403,9924"; a="189369498" X-IronPort-AV: E=Sophos;i="5.81,251,1610438400"; d="scan'208";a="189369498" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2021 08:11:32 -0700 IronPort-SDR: gj+WE5fkO/VYqGjB4KZ7jB9zpahFHSYquIF/cGoTfPLWwOpDzu1BVt93UiX5QEwwvpLMtM0Dl0 IpxWaBnFlPVQ== X-IronPort-AV: E=Sophos;i="5.81,251,1610438400"; d="scan'208";a="405570311" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2021 08:11:31 -0700 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang Cc: Yu-cheng Yu Subject: [PATCH v23 20/28] mm/mprotect: Exclude shadow stack from preserve_write Date: Tue, 16 Mar 2021 08:10:46 -0700 Message-Id: <20210316151054.5405-21-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210316151054.5405-1-yu-cheng.yu@intel.com> References: <20210316151054.5405-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In change_pte_range(), when a PTE is changed for prot_numa, _PAGE_RW is preserved to avoid the additional write fault after the NUMA hinting fault. However, pte_write() now includes both normal writable and shadow stack (RW=0, Dirty=1) PTEs, but the latter does not have _PAGE_RW and has no need to preserve it. Exclude shadow stack from preserve_write test, and apply the same change to change_huge_pmd(). Signed-off-by: Yu-cheng Yu --- mm/huge_memory.c | 7 ++++++- mm/mprotect.c | 9 ++++++++- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 3ad7d521a7b5..107c2be2156d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1812,12 +1812,17 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, bool prot_numa = cp_flags & MM_CP_PROT_NUMA; bool uffd_wp = cp_flags & MM_CP_UFFD_WP; bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; + bool shstk = arch_shadow_stack_mapping(vma->vm_flags); ptl = __pmd_trans_huge_lock(pmd, vma); if (!ptl) return 0; - preserve_write = prot_numa && pmd_write(*pmd); + /* + * Preserve only normal writable huge PMD, but not shadow + * stack (RW=0, Dirty=1). + */ + preserve_write = prot_numa && pmd_write(*pmd) && !shstk; ret = 1; #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION diff --git a/mm/mprotect.c b/mm/mprotect.c index c1ce78d688b6..e69278b346a9 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -75,7 +75,14 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, oldpte = *pte; if (pte_present(oldpte)) { pte_t ptent; - bool preserve_write = prot_numa && pte_write(oldpte); + bool shstk = arch_shadow_stack_mapping(vma->vm_flags); + bool preserve_write; + + /* + * Preserve only normal writable PTE, but not shadow + * stack (RW=0, Dirty=1). + */ + preserve_write = prot_numa && pte_write(oldpte) && !shstk; /* * Avoid trapping faults against the zero or KSM -- 2.21.0