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 B0E69C4332B for ; Tue, 29 Dec 2020 21:35:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97B64221F8 for ; Tue, 29 Dec 2020 21:35:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727244AbgL2VfK (ORCPT ); Tue, 29 Dec 2020 16:35:10 -0500 Received: from mga03.intel.com ([134.134.136.65]:11891 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726634AbgL2Vda (ORCPT ); Tue, 29 Dec 2020 16:33:30 -0500 IronPort-SDR: vcnDB6M018wPdVqM8vCq7Vqj5oAsI8+d5TZBl29GTDuzqd7b9cRIlcsnTyzqZIQKZ8RJ0jwT1X N0iVXT4qOxQg== X-IronPort-AV: E=McAfee;i="6000,8403,9849"; a="176640521" X-IronPort-AV: E=Sophos;i="5.78,459,1599548400"; d="scan'208";a="176640521" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Dec 2020 13:32:22 -0800 IronPort-SDR: j13N8E9XHMcV/WRTGcgWjlHw0WUXJIXKK4VcsVYNZR9GWdPFXf5UT1GvBgWmG6FnXqRdpDStip 09KmImfaBZ5g== X-IronPort-AV: E=Sophos;i="5.78,459,1599548400"; d="scan'208";a="376189603" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Dec 2020 13:32:22 -0800 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 Cc: Yu-cheng Yu Subject: [PATCH v17 10/26] x86/mm: Update pte_modify for _PAGE_COW Date: Tue, 29 Dec 2020 13:30:37 -0800 Message-Id: <20201229213053.16395-11-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20201229213053.16395-1-yu-cheng.yu@intel.com> References: <20201229213053.16395-1-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 The read-only and Dirty PTE has been used to indicate copy-on-write pages. However, newer x86 processors also regard a read-only and Dirty PTE as a shadow stack page. In order to separate the two, the software-defined _PAGE_COW is created to replace _PAGE_DIRTY for the copy-on-write case, and pte_*() are updated. Pte_modify() changes a PTE to 'newprot', but it doesn't use the pte_*(). Introduce fixup_dirty_pte(), which sets a dirty PTE, based on _PAGE_RW, to either _PAGE_DIRTY or _PAGE_COW. Apply the same changes to pmd_modify(). Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/pgtable.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 61e4d3b17d87..666c25ab9564 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -723,6 +723,21 @@ static inline pmd_t pmd_mkinvalid(pmd_t pmd) static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); +static inline pteval_t fixup_dirty_pte(pteval_t pteval) +{ + pte_t pte = __pte(pteval); + + if (cpu_feature_enabled(X86_FEATURE_SHSTK) && pte_dirty(pte)) { + pte = pte_mkclean(pte); + + if (pte_flags(pte) & _PAGE_RW) + pte = pte_set_flags(pte, _PAGE_DIRTY); + else + pte = pte_set_flags(pte, _PAGE_COW); + } + return pte_val(pte); +} + static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) { pteval_t val = pte_val(pte), oldval = val; @@ -733,16 +748,34 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) */ val &= _PAGE_CHG_MASK; val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK; + val = fixup_dirty_pte(val); val = flip_protnone_guard(oldval, val, PTE_PFN_MASK); return __pte(val); } +static inline int pmd_write(pmd_t pmd); +static inline pmdval_t fixup_dirty_pmd(pmdval_t pmdval) +{ + pmd_t pmd = __pmd(pmdval); + + if (cpu_feature_enabled(X86_FEATURE_SHSTK) && pmd_dirty(pmd)) { + pmd = pmd_mkclean(pmd); + + if (pmd_flags(pmd) & _PAGE_RW) + pmd = pmd_set_flags(pmd, _PAGE_DIRTY); + else + pmd = pmd_set_flags(pmd, _PAGE_COW); + } + return pmd_val(pmd); +} + static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { pmdval_t val = pmd_val(pmd), oldval = val; val &= _HPAGE_CHG_MASK; val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK; + val = fixup_dirty_pmd(val); val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK); return __pmd(val); } -- 2.21.0