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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7E07C43219 for ; Sun, 30 Jan 2022 21:24:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356687AbiA3VYt (ORCPT ); Sun, 30 Jan 2022 16:24:49 -0500 Received: from mga06.intel.com ([134.134.136.31]:52048 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356664AbiA3VWU (ORCPT ); Sun, 30 Jan 2022 16:22:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643577740; x=1675113740; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=Swb/A+mwAZL7amzdZG31LHVm/8xpjESoIsbIiYe+fFo=; b=LrrSajmxvxfHBx2P0/AoXjkO3MGajkhEh3/7D9nYFuXSH+xjrArgaXmB awIA9qE31uIbvkVmeZfI41ifrjJY1Vf55br+sp0NpY19ZWRSiVVgVeFiV mSgHQIrz2UvdfpaladJcHuFDxbl8FQzg6YaCC1T0xKF1sUDQE4rmLhhIx 7Qd67KBsXQTs2e3QtJJCjErfNsqWw4I1HvjZ+Y7uPcx+2wyDw4OThHnfx h14PxFwIWK3rRkRataU7OZgZg+NvqdDOl8BIV+BVftAZPh/0vumkY7QTt rt3KjslQz3RoOhRj1yOHy0PaOOBvvQBKCtAr+bGJQkDZEfnl00BSBA77i Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10243"; a="308104951" X-IronPort-AV: E=Sophos;i="5.88,329,1635231600"; d="scan'208";a="308104951" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2022 13:22:02 -0800 X-IronPort-AV: E=Sophos;i="5.88,329,1635231600"; d="scan'208";a="536856845" Received: from avmallar-mobl1.amr.corp.intel.com (HELO rpedgeco-desk.amr.corp.intel.com) ([10.209.123.171]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2022 13:22:01 -0800 From: Rick Edgecombe 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" , Dave Martin , Weijiang Yang , "Kirill A . Shutemov" , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com Cc: rick.p.edgecombe@intel.com, Yu-cheng Yu Subject: [PATCH 21/35] mm/mprotect: Exclude shadow stack from preserve_write Date: Sun, 30 Jan 2022 13:18:24 -0800 Message-Id: <20220130211838.8382-22-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220130211838.8382-1-rick.p.edgecombe@intel.com> References: <20220130211838.8382-1-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Yu-cheng Yu 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 Signed-off-by: Rick Edgecombe --- 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 1c7167e6f223..01375e39b52b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1750,6 +1750,13 @@ 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 b0012c13a00e..faac710f0891 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. -- 2.17.1