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 B7792C47085 for ; Fri, 21 May 2021 22:13:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 65D09613E4 for ; Fri, 21 May 2021 22:13:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65D09613E4 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 3EB4B8E005A; Fri, 21 May 2021 18:13:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 88E288E0058; Fri, 21 May 2021 18:13:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C3AE88E005D; Fri, 21 May 2021 18:13:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0247.hostedemail.com [216.40.44.247]) by kanga.kvack.org (Postfix) with ESMTP id 6E10B8E005A for ; Fri, 21 May 2021 18:13:18 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0FCE36D65 for ; Fri, 21 May 2021 22:13:18 +0000 (UTC) X-FDA: 78166640076.07.8BA709A Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf06.hostedemail.com (Postfix) with ESMTP id 7DC35C0042D0 for ; Fri, 21 May 2021 22:13:14 +0000 (UTC) IronPort-SDR: rBon8HxwA0OwvMLQz59FFRhurQdeEBaIkPlWBGUFBDbeELqKbyN/QlFVkkAhHt7jwv+aw08neZ oF5HBx1jCoXg== X-IronPort-AV: E=McAfee;i="6200,9189,9991"; a="201618766" X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="201618766" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2021 15:13:16 -0700 IronPort-SDR: Of+dDb9hTap5OEQ0XFJ97KnmIuCR/08/dRnp5yxCFtZ9/M/ti8HwYJOhNZQi/d8sZIN6ymZy3y 9nDs90G7mpxQ== X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="441116191" 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; 21 May 2021 15:13:14 -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 Cc: Yu-cheng Yu , "Kirill A . Shutemov" Subject: [PATCH v27 16/31] x86/mm: Update maybe_mkwrite() for shadow stack Date: Fri, 21 May 2021 15:11:56 -0700 Message-Id: <20210521221211.29077-17-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210521221211.29077-1-yu-cheng.yu@intel.com> References: <20210521221211.29077-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Authentication-Results: imf06.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf06.hostedemail.com: domain of yu-cheng.yu@intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=yu-cheng.yu@intel.com X-Stat-Signature: ta8z6rkfsri38ezfy7eg6ph67fdprt7d X-Rspamd-Queue-Id: 7DC35C0042D0 X-Rspamd-Server: rspam02 X-HE-Tag: 1621635194-755960 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 e61ad0946212..996ce14d8ab4 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -308,6 +308,9 @@ 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) { @@ -1686,6 +1689,9 @@ 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 d27cf69e811d..702112a86c8a 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 587f7399847b..1e57c2b823ed 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1012,12 +1012,14 @@ 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 63ed6b25deaa..e613278fe5e1 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -479,12 +479,14 @@ 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