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=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 3F845C433E0 for ; Wed, 10 Mar 2021 22:01:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E406A64E27 for ; Wed, 10 Mar 2021 22:01:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E406A64E27 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 CE36B8D0223; Wed, 10 Mar 2021 17:01:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BF78D8D0226; Wed, 10 Mar 2021 17:01:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8748C8D0227; Wed, 10 Mar 2021 17:01:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0223.hostedemail.com [216.40.44.223]) by kanga.kvack.org (Postfix) with ESMTP id 5B5438D0223 for ; Wed, 10 Mar 2021 17:01:21 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id EFC90181AF5C3 for ; Wed, 10 Mar 2021 22:01:20 +0000 (UTC) X-FDA: 77905336320.22.92AE158 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf15.hostedemail.com (Postfix) with ESMTP id 8427DA0009FE for ; Wed, 10 Mar 2021 22:01:19 +0000 (UTC) IronPort-SDR: H9KIXwivZ3ewLG0Zktj+Yh1ljHx5RosJRCK5aRdG52cjyFuv2c7J2s3CncLGf+fM0NrK1Y481V FWwnT5nGUv4w== X-IronPort-AV: E=McAfee;i="6000,8403,9919"; a="167846438" X-IronPort-AV: E=Sophos;i="5.81,238,1610438400"; d="scan'208";a="167846438" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2021 14:01:15 -0800 IronPort-SDR: dzLhrxnnWCqFrtgCha4JCLnZfeyW1tMK5mj66/v7y7b0whNH0MTj373NFq4dndfiw1NaFyzT8U 6lH6bBIs13Eg== X-IronPort-AV: E=Sophos;i="5.81,238,1610438400"; d="scan'208";a="403847612" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2021 14:01:15 -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 v22 11/28] x86/mm: Update pte_modify for _PAGE_COW Date: Wed, 10 Mar 2021 14:00:29 -0800 Message-Id: <20210310220046.15866-12-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210310220046.15866-1-yu-cheng.yu@intel.com> References: <20210310220046.15866-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 X-Stat-Signature: njnwa8ixa86cg6rnozqjsr9m3f57yna4 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 8427DA0009FE Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf15; identity=mailfrom; envelope-from=""; helo=mga12.intel.com; client-ip=192.55.52.136 X-HE-DKIM-Result: none/none X-HE-Tag: 1615413679-12812 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 --- arch/x86/include/asm/pgtable.h | 37 ++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtabl= e.h index 9c056d5815de..e1739f590ca6 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -799,6 +799,23 @@ 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); + + /* + * Fix up potential shadow stack page flags because the RO, Dirty + * PTE is special. + */ + if (cpu_feature_enabled(X86_FEATURE_SHSTK)) { + if (pte_dirty(pte)) { + pte =3D pte_mkclean(pte); + pte =3D pte_mkdirty(pte); + } + } + 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; @@ -809,16 +826,36 @@ 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); + + /* + * Fix up potential shadow stack page flags because the RO, Dirty + * PMD is special. + */ + if (cpu_feature_enabled(X86_FEATURE_SHSTK)) { + if (pmd_dirty(pmd)) { + pmd =3D pmd_mkclean(pmd); + pmd =3D pmd_mkdirty(pmd); + } + } + 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