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 596BFC433E9 for ; Wed, 10 Feb 2021 17:58:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E0EA764EDA for ; Wed, 10 Feb 2021 17:58:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0EA764EDA 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 5B04B6B007D; Wed, 10 Feb 2021 12:58:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 53D026B007E; Wed, 10 Feb 2021 12:58:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2FACC6B0080; Wed, 10 Feb 2021 12:58:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0187.hostedemail.com [216.40.44.187]) by kanga.kvack.org (Postfix) with ESMTP id ED37E6B007D for ; Wed, 10 Feb 2021 12:58:07 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id B23E812C9 for ; Wed, 10 Feb 2021 17:58:07 +0000 (UTC) X-FDA: 77803117014.24.test95_1d162e027611 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 9345B1A4A0 for ; Wed, 10 Feb 2021 17:58:07 +0000 (UTC) X-HE-Tag: test95_1d162e027611 X-Filterd-Recvd-Size: 5188 Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Wed, 10 Feb 2021 17:58:06 +0000 (UTC) IronPort-SDR: YfV5OwSN+lnEeWidr/NoXy9uyN4qfSILeTkAS+omVnuwpbGAKmwNTY+obORZanh47rf6Cx52iL MNLORma/122Q== X-IronPort-AV: E=McAfee;i="6000,8403,9891"; a="243612378" X-IronPort-AV: E=Sophos;i="5.81,168,1610438400"; d="scan'208";a="243612378" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2021 09:58:01 -0800 IronPort-SDR: Hbq2pjG6EeDUzlxXiP9LB7PHTcMmBrl5Sfg4G35ANBkYUHjix5Ir60I9xGeM9DD02PAPJbknzx SRLUy6eNEhWQ== X-IronPort-AV: E=Sophos;i="5.81,168,1610438400"; d="scan'208";a="421140742" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2021 09:58:01 -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 v20 10/25] x86/mm: Update pte_modify for _PAGE_COW Date: Wed, 10 Feb 2021 09:56:48 -0800 Message-Id: <20210210175703.12492-11-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210210175703.12492-1-yu-cheng.yu@intel.com> References: <20210210175703.12492-1-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 2309fa9d412e..b867f5ee862f 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -736,6 +736,21 @@ 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; @@ -746,16 +761,34 @@ 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