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 B1367C04FE3 for ; Thu, 22 Jul 2021 20:53:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4F17660F02 for ; Thu, 22 Jul 2021 20:53:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4F17660F02 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id A97208E000B; Thu, 22 Jul 2021 16:53:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9D4A78E000A; Thu, 22 Jul 2021 16:53:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F1898E000B; Thu, 22 Jul 2021 16:53:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0211.hostedemail.com [216.40.44.211]) by kanga.kvack.org (Postfix) with ESMTP id 003F88E0006 for ; Thu, 22 Jul 2021 16:53:05 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E0969211DD for ; Thu, 22 Jul 2021 20:53:04 +0000 (UTC) X-FDA: 78391423488.19.CE57C74 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by imf02.hostedemail.com (Postfix) with ESMTP id 5DF6870024D9 for ; Thu, 22 Jul 2021 20:53:04 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10053"; a="209845089" X-IronPort-AV: E=Sophos;i="5.84,262,1620716400"; d="scan'208";a="209845089" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jul 2021 13:53:01 -0700 X-IronPort-AV: E=Sophos;i="5.84,262,1620716400"; d="scan'208";a="502035473" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jul 2021 13:53:01 -0700 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 , Rick P Edgecombe Cc: Yu-cheng Yu , "Kirill A . Shutemov" Subject: [PATCH v28 16/32] x86/mm: Update maybe_mkwrite() for shadow stack Date: Thu, 22 Jul 2021 13:52:03 -0700 Message-Id: <20210722205219.7934-17-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210722205219.7934-1-yu-cheng.yu@intel.com> References: <20210722205219.7934-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Authentication-Results: imf02.hostedemail.com; dkim=none; spf=none (imf02.hostedemail.com: domain of yu-cheng.yu@intel.com has no SPF policy when checking 192.55.52.120) smtp.mailfrom=yu-cheng.yu@intel.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none) X-Rspamd-Server: rspam02 X-Stat-Signature: 7bqc4d8uqabxkhf8wtesnxei8g35nur6 X-Rspamd-Queue-Id: 5DF6870024D9 X-HE-Tag: 1626987184-198110 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: When serving a page fault, maybe_mkwrite() makes a PTE writable if its vm= a has VM_WRITE. A shadow stack vma has VM_SHADOW_STACK. Its PTEs have _PAGE_DIRTY, but n= ot _PAGE_WRITE. In fork(), _PAGE_DIRTY is cleared to cause copy-on-write, and in the page fault handler, _PAGE_DIRTY is restored and the shadow sta= ck page is writable again. Introduce an x86 version of maybe_mkwrite(), which sets proper PTE bits according to VM flags. Apply the same changes to maybe_pmd_mkwrite(). Signed-off-by: Yu-cheng Yu Reviewed-by: Kirill A. Shutemov Cc: Kees Cook --- arch/x86/include/asm/pgtable.h | 6 ++++++ arch/x86/mm/pgtable.c | 20 ++++++++++++++++++++ include/linux/mm.h | 2 ++ mm/huge_memory.c | 2 ++ 4 files changed, 30 insertions(+) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtabl= e.h index df4ce715560a..bfe4ea2b652d 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -280,6 +280,9 @@ static inline int pmd_trans_huge(pmd_t pmd) return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) =3D=3D _PAGE_PSE; } =20 +#define maybe_pmd_mkwrite maybe_pmd_mkwrite +extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); + #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD static inline int pud_trans_huge(pud_t pud) { @@ -1632,6 +1635,9 @@ static inline bool arch_faults_on_old_pte(void) return false; } =20 +#define maybe_mkwrite maybe_mkwrite +extern pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma); + #endif /* __ASSEMBLY__ */ =20 #endif /* _ASM_X86_PGTABLE_H */ diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 3364fe62b903..ba449d12ec32 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -610,6 +610,26 @@ int pmdp_clear_flush_young(struct vm_area_struct *vm= a, } #endif =20 +pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) +{ + if (likely(vma->vm_flags & VM_WRITE)) + pte =3D pte_mkwrite(pte); + else if (likely(vma->vm_flags & VM_SHADOW_STACK)) + pte =3D pte_mkwrite_shstk(pte); + return pte; +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) +{ + if (likely(vma->vm_flags & VM_WRITE)) + pmd =3D pmd_mkwrite(pmd); + else if (likely(vma->vm_flags & VM_SHADOW_STACK)) + pmd =3D pmd_mkwrite_shstk(pmd); + return pmd; +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + /** * reserve_top_address - reserves a hole in the top of kernel address sp= ace * @reserve - size of hole to reserve diff --git a/include/linux/mm.h b/include/linux/mm.h index 4a9985e50819..4548f75cef14 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1015,12 +1015,14 @@ void free_compound_page(struct page *page); * pte_mkwrite. But get_user_pages can cause write faults for mappings * that do not have writing enabled, when used by access_process_vm. */ +#ifndef maybe_mkwrite static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) { if (likely(vma->vm_flags & VM_WRITE)) pte =3D pte_mkwrite(pte); return pte; } +#endif =20 vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page); void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long a= ddr); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index afff3ac87067..c8dd5913884e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -491,12 +491,14 @@ static int __init setup_transparent_hugepage(char *= str) } __setup("transparent_hugepage=3D", setup_transparent_hugepage); =20 +#ifndef maybe_pmd_mkwrite pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) { if (likely(vma->vm_flags & VM_WRITE)) pmd =3D pmd_mkwrite(pmd); return pmd; } +#endif =20 #ifdef CONFIG_MEMCG static inline struct deferred_split *get_deferred_split_queue(struct pag= e *page) --=20 2.21.0