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 E70C5C433ED for ; Thu, 1 Apr 2021 22:12:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B203961105 for ; Thu, 1 Apr 2021 22:12:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235863AbhDAWMM (ORCPT ); Thu, 1 Apr 2021 18:12:12 -0400 Received: from mga11.intel.com ([192.55.52.93]:34674 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235702AbhDAWLu (ORCPT ); Thu, 1 Apr 2021 18:11:50 -0400 IronPort-SDR: wdOY/stPVv3L58Wurk10jldMPS46mYOD0ArLoHual6dxA+uFuw0ORLAHuaKsTNsHiShTdrj59N cfxrko8XG+mw== X-IronPort-AV: E=McAfee;i="6000,8403,9941"; a="189084602" X-IronPort-AV: E=Sophos;i="5.81,296,1610438400"; d="scan'208";a="189084602" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2021 15:11:25 -0700 IronPort-SDR: sTX5EcqB6UoM1GQbqIQAS2KqnI1IFu/iUCzmeuQS8gLIVyp0R8L/oDLZD3dX1q725MoNJpacjv 0ebazLkWEmnw== X-IronPort-AV: E=Sophos;i="5.81,296,1610438400"; d="scan'208";a="517513929" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2021 15:11:25 -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 , "Kirill A . Shutemov" Subject: [PATCH v24 20/30] mm/mprotect: Exclude shadow stack from preserve_write Date: Thu, 1 Apr 2021 15:10:54 -0700 Message-Id: <20210401221104.31584-21-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210401221104.31584-1-yu-cheng.yu@intel.com> References: <20210401221104.31584-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-api@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 Cc: Kirill A. Shutemov --- v24: - Change arch_shadow_stack_mapping() to is_shadow_stack_mapping(). 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 65fc0aedd577..1d41138c4f74 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 = is_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..550448dc5ff1 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 = is_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