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 99C41C43611 for ; Tue, 27 Apr 2021 20:45:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BA88613BC for ; Tue, 27 Apr 2021 20:45:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239322AbhD0UqW (ORCPT ); Tue, 27 Apr 2021 16:46:22 -0400 Received: from mga05.intel.com ([192.55.52.43]:31779 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239187AbhD0UqE (ORCPT ); Tue, 27 Apr 2021 16:46:04 -0400 IronPort-SDR: DFu8Y5eUlS2mB0E8PyYl00hOzaZa7sTiljWqa/7dIuSQzaUwEqdYYiV7+0FLomuiaxT5hi4o8R W0KRDPHV7s9A== X-IronPort-AV: E=McAfee;i="6200,9189,9967"; a="281922487" X-IronPort-AV: E=Sophos;i="5.82,255,1613462400"; d="scan'208";a="281922487" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2021 13:44:20 -0700 IronPort-SDR: Joo7589v8RQFTBvQzvuNM/X3aTnf2/jdVcBYeVk2Ys7N8y3DoL6PpG9QEoSq8kJHk9R3o1lsKp hnpuSNTa3X/w== X-IronPort-AV: E=Sophos;i="5.82,255,1613462400"; d="scan'208";a="465623535" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2021 13:44:19 -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 v26 20/30] mm/mprotect: Exclude shadow stack from preserve_write Date: Tue, 27 Apr 2021 13:43:05 -0700 Message-Id: <20210427204315.24153-21-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210427204315.24153-1-yu-cheng.yu@intel.com> References: <20210427204315.24153-1-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 Reviewed-by: Kirill A. Shutemov --- v25: - Move is_shadow_stack_mapping() to a separate line. v24: - Change arch_shadow_stack_mapping() to is_shadow_stack_mapping(). mm/huge_memory.c | 7 +++++++ mm/mprotect.c | 7 +++++++ 2 files changed, 14 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cf10c3822853..3b841d7efd13 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1824,6 +1824,13 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, return 0; preserve_write = prot_numa && pmd_write(*pmd); + + /* + * Preserve only normal writable huge PMD, but not shadow + * stack (RW=0, Dirty=1). + */ + if (is_shadow_stack_mapping(vma->vm_flags)) + preserve_write = false; ret = 1; #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION diff --git a/mm/mprotect.c b/mm/mprotect.c index c1ce78d688b6..3b2f0d75519f 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -77,6 +77,13 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, pte_t ptent; bool preserve_write = prot_numa && pte_write(oldpte); + /* + * Preserve only normal writable PTE, but not shadow + * stack (RW=0, Dirty=1). + */ + if (is_shadow_stack_mapping(vma->vm_flags)) + preserve_write = false; + /* * Avoid trapping faults against the zero or KSM * pages. See similar comment in change_huge_pmd. -- 2.21.0