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=-16.7 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=ham 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 1C9BDC433E6 for ; Wed, 17 Feb 2021 22:28:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B7F7A64E2E for ; Wed, 17 Feb 2021 22:28:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7F7A64E2E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BBDF08D0001; Wed, 17 Feb 2021 17:28:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AF8788D0006; Wed, 17 Feb 2021 17:28:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 74C9D8D0001; Wed, 17 Feb 2021 17:28:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0132.hostedemail.com [216.40.44.132]) by kanga.kvack.org (Postfix) with ESMTP id 348418D0003 for ; Wed, 17 Feb 2021 17:28:02 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 075173626 for ; Wed, 17 Feb 2021 22:28:02 +0000 (UTC) X-FDA: 77829198804.13.fruit19_3c014d927650 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin13.hostedemail.com (Postfix) with ESMTP id DC81B18140B67 for ; Wed, 17 Feb 2021 22:28:01 +0000 (UTC) X-HE-Tag: fruit19_3c014d927650 X-Filterd-Recvd-Size: 5201 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Wed, 17 Feb 2021 22:28:00 +0000 (UTC) IronPort-SDR: cAVTXzbVO4tl8Qzo+0wUMQDSFY9dJl8/hnT4Uhhwz70K50qzDA9Hr7i/dmuOMyavdpBaTyVvAt fbE/XUYAyaCw== X-IronPort-AV: E=McAfee;i="6000,8403,9898"; a="170994007" X-IronPort-AV: E=Sophos;i="5.81,185,1610438400"; d="scan'208";a="170994007" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2021 14:27:59 -0800 IronPort-SDR: GFEoT9zbhOHBKiJdZcFU2ase27NBTo7UN4Ek6RrwPFSnb2ogXOHKwxGXRhxHf//de0tyXF0BF2 4rE0Hto8eEhg== X-IronPort-AV: E=Sophos;i="5.81,185,1610438400"; d="scan'208";a="400172622" 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; 17 Feb 2021 14:27:58 -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 , Haitao Huang Cc: Yu-cheng Yu Subject: [PATCH v21 10/26] x86/mm: Update pte_modify for _PAGE_COW Date: Wed, 17 Feb 2021 14:27:14 -0800 Message-Id: <20210217222730.15819-11-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210217222730.15819-1-yu-cheng.yu@intel.com> References: <20210217222730.15819-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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, a= nd 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 Reviewed-by: Kees Cook --- 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/pgtabl= e.h index 1a6c0784af0a..7a7f6af01ab5 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -777,6 +777,21 @@ static inline pmd_t pmd_mkinvalid(pmd_t pmd) =20 static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); =20 +static inline pteval_t fixup_dirty_pte(pteval_t pteval) +{ + pte_t pte =3D __pte(pteval); + + if (cpu_feature_enabled(X86_FEATURE_SHSTK) && pte_dirty(pte)) { + pte =3D pte_mkclean(pte); + + if (pte_flags(pte) & _PAGE_RW) + pte =3D pte_set_flags(pte, _PAGE_DIRTY); + else + pte =3D 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 =3D pte_val(pte), oldval =3D val; @@ -787,16 +802,34 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t = newprot) */ val &=3D _PAGE_CHG_MASK; val |=3D check_pgprot(newprot) & ~_PAGE_CHG_MASK; + val =3D fixup_dirty_pte(val); val =3D flip_protnone_guard(oldval, val, PTE_PFN_MASK); return __pte(val); } =20 +static inline int pmd_write(pmd_t pmd); +static inline pmdval_t fixup_dirty_pmd(pmdval_t pmdval) +{ + pmd_t pmd =3D __pmd(pmdval); + + if (cpu_feature_enabled(X86_FEATURE_SHSTK) && pmd_dirty(pmd)) { + pmd =3D pmd_mkclean(pmd); + + if (pmd_flags(pmd) & _PAGE_RW) + pmd =3D pmd_set_flags(pmd, _PAGE_DIRTY); + else + pmd =3D 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 =3D pmd_val(pmd), oldval =3D val; =20 val &=3D _HPAGE_CHG_MASK; val |=3D check_pgprot(newprot) & ~_HPAGE_CHG_MASK; + val =3D fixup_dirty_pmd(val); val =3D flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK); return __pmd(val); } --=20 2.21.0