From patchwork Sun Jan 30 21:18:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Edgecombe, Rick P" X-Patchwork-Id: 12730141 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7341C4167B for ; Sun, 30 Jan 2022 21:22:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CCB9D6B0085; Sun, 30 Jan 2022 16:21:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C2CED6B0087; Sun, 30 Jan 2022 16:21:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 993096B0089; Sun, 30 Jan 2022 16:21:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0163.hostedemail.com [216.40.44.163]) by kanga.kvack.org (Postfix) with ESMTP id 8A3CC6B0085 for ; Sun, 30 Jan 2022 16:21:56 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 4CDFC8249980 for ; Sun, 30 Jan 2022 21:21:56 +0000 (UTC) X-FDA: 79088225832.28.71E98B2 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by imf18.hostedemail.com (Postfix) with ESMTP id A64FB1C0005 for ; Sun, 30 Jan 2022 21:21:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643577715; x=1675113715; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=HHh4lkLfyu0d0fqFw9G2b577iSJVRa+u0pjug6+8QXs=; b=RTdGMa0EibAKAzXyixV3brxqogUSs/l8xbFNOE6YKM2OJGRM/BYih7km RxLkcuGaS9c3TRoZGt2OcqZWXKZA7NdiY6ywiYAuM6xcsSh5bSeKnsw33 znEQDjbqhwOHL39l4eF4tC7kjwkmsn5VtB2RTYuHXsKEuQ5tQOGJscK8g AhbgASzbUyPeq0GI3LODjKFWTEJr29P2/BonwnTCyUkysMz6gIjF88RTe nFrhnqwoIbBc/Kju6K5SjLm8ecwR3URIaMmNb8JW8BQF8SqkFZtxoqvHu 6DrPdhsz6pxDsNtAeNfBCyrzuN//lU9v1LrLXu3tEDt05FvMsKGAcj80c Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10243"; a="244970201" X-IronPort-AV: E=Sophos;i="5.88,329,1635231600"; d="scan'208";a="244970201" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2022 13:21:55 -0800 X-IronPort-AV: E=Sophos;i="5.88,329,1635231600"; d="scan'208";a="536856751" 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 13:21:54 -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 11/35] x86/mm: Update pte_modify for _PAGE_COW Date: Sun, 30 Jan 2022 13:18:14 -0800 Message-Id: <20220130211838.8382-12-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> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: A64FB1C0005 X-Stat-Signature: bxra4ixysb61ufzoh9831i98cnk7h5hr X-Rspam-User: nil Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=RTdGMa0E; spf=none (imf18.hostedemail.com: domain of rick.p.edgecombe@intel.com has no SPF policy when checking 192.55.52.93) smtp.mailfrom=rick.p.edgecombe@intel.com; dmarc=pass (policy=none) header.from=intel.com X-HE-Tag: 1643577715-567705 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: From: Yu-cheng Yu 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 Reviewed-by: Kirill A. Shutemov Signed-off-by: Rick Edgecombe --- 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/pgtable.h index a4a75e78a934..5c3886f6ccda 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -773,6 +773,23 @@ 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); + + /* + * 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 = pte_mkclean(pte); + pte = pte_mkdirty(pte); + } + } + return pte_val(pte); +} + static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) { pteval_t val = pte_val(pte), oldval = val; @@ -783,16 +800,36 @@ 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); + + /* + * 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 = pmd_mkclean(pmd); + pmd = pmd_mkdirty(pmd); + } + } + 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); }