From patchwork Thu Apr 15 22:14:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu-cheng Yu X-Patchwork-Id: 12206147 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 6CAF9C433B4 for ; Thu, 15 Apr 2021 22:16:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 247E861103 for ; Thu, 15 Apr 2021 22:16:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 247E861103 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 9FB6E8D0007; Thu, 15 Apr 2021 18:15:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 97E238E0003; Thu, 15 Apr 2021 18:15:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 50E7F8D0008; Thu, 15 Apr 2021 18:15:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0047.hostedemail.com [216.40.44.47]) by kanga.kvack.org (Postfix) with ESMTP id 280588D0009 for ; Thu, 15 Apr 2021 18:15:41 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id D3E8F1E0C for ; Thu, 15 Apr 2021 22:15:40 +0000 (UTC) X-FDA: 78036009240.36.A09BFF5 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by imf15.hostedemail.com (Postfix) with ESMTP id 51E8BA00038D for ; Thu, 15 Apr 2021 22:15:38 +0000 (UTC) IronPort-SDR: p0+3jFSlkyF/qBRW+Zu1VNtW7lbH0NxIVayDzOfDzxjXaoyxSH6vmzUxfoY+tBZ6mTeebI/fN2 4mJhwxQDUm+Q== X-IronPort-AV: E=McAfee;i="6200,9189,9955"; a="191764337" X-IronPort-AV: E=Sophos;i="5.82,225,1613462400"; d="scan'208";a="191764337" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2021 15:15:37 -0700 IronPort-SDR: 8QKDQHvakxmEqG/LOITayInnTAP/ePp201BcMsAts0BnBeQ3ABafrYu9drXGbbTMfIOx3fFllT JUZsNO7FuPjg== X-IronPort-AV: E=Sophos;i="5.82,225,1613462400"; d="scan'208";a="451270906" 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; 15 Apr 2021 15:15:36 -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 v25 15/30] x86/mm: Update maybe_mkwrite() for shadow stack Date: Thu, 15 Apr 2021 15:14:04 -0700 Message-Id: <20210415221419.31835-16-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210415221419.31835-1-yu-cheng.yu@intel.com> References: <20210415221419.31835-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 51E8BA00038D X-Stat-Signature: dejuk18d47dy5yj7rp1rypansr1bqxms X-Rspamd-Server: rspam02 Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf15; identity=mailfrom; envelope-from=""; helo=mga11.intel.com; client-ip=192.55.52.93 X-HE-DKIM-Result: none/none X-HE-Tag: 1618524938-655307 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 vma has VM_WRITE. A shadow stack vma has VM_SHADOW_STACK. Its PTEs have _PAGE_DIRTY, but not _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 stack 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 --- v24: - Instead of doing arch_maybe_mkwrite(), overwrite maybe*_mkwrite() with x86 versions. - Change VM_SHSTK to VM_SHADOW_STACK. 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/pgtable.h index 46d9394b884f..da5dea417663 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)) == _PAGE_PSE; } +#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; } +#define maybe_mkwrite maybe_mkwrite +extern pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma); + #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_H */ diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index f6a9e2e36642..e778dbbef3d8 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 *vma, } #endif +pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) +{ + if (likely(vma->vm_flags & VM_WRITE)) + pte = pte_mkwrite(pte); + else if (likely(vma->vm_flags & VM_SHADOW_STACK)) + pte = 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 = pmd_mkwrite(pmd); + else if (likely(vma->vm_flags & VM_SHADOW_STACK)) + pmd = pmd_mkwrite_shstk(pmd); + return pmd; +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + /** * reserve_top_address - reserves a hole in the top of kernel address space * @reserve - size of hole to reserve diff --git a/include/linux/mm.h b/include/linux/mm.h index 08282eb2f195..6ac9b3e9a865 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -993,12 +993,14 @@ 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 = pte_mkwrite(pte); return pte; } +#endif 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 addr); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ae907a9c2050..8203bd6ae4bd 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -478,12 +478,14 @@ static int __init setup_transparent_hugepage(char *str) } __setup("transparent_hugepage=", setup_transparent_hugepage); +#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 = pmd_mkwrite(pmd); return pmd; } +#endif #ifdef CONFIG_MEMCG static inline struct deferred_split *get_deferred_split_queue(struct page *page)