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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 9970CC433E2 for ; Fri, 26 Mar 2021 15:47:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FF7E619FF for ; Fri, 26 Mar 2021 15:47:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230271AbhCZPqt (ORCPT ); Fri, 26 Mar 2021 11:46:49 -0400 Received: from mga17.intel.com ([192.55.52.151]:36224 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230080AbhCZPqc (ORCPT ); Fri, 26 Mar 2021 11:46:32 -0400 IronPort-SDR: tjLCPTysDovHN6DDZ7lTA8gswryivK3tZFil2gHhskdY+plTSqIt1651uA1yFpdzm1/p1sLKmj SsvAlW/uNaMg== X-IronPort-AV: E=McAfee;i="6000,8403,9935"; a="171162278" X-IronPort-AV: E=Sophos;i="5.81,280,1610438400"; d="scan'208";a="171162278" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Mar 2021 08:46:32 -0700 IronPort-SDR: 4LVgfPVpdmkD7cfo8pmJomTC9ws0nhuVEuHkPVnvQyKK3SXozc7p1edP3lq/iDypY7mT73MZ8q FiFTPZ8L5a1A== X-IronPort-AV: E=Sophos;i="5.81,280,1610438400"; d="scan'208";a="443390230" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.209.171.114]) ([10.209.171.114]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Mar 2021 08:46:31 -0700 Subject: Re: [PATCH v23 18/28] mm/mmap: Add shadow stack pages to memory accounting To: "Kirill A. Shutemov" Cc: 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 References: <20210316151054.5405-1-yu-cheng.yu@intel.com> <20210316151054.5405-19-yu-cheng.yu@intel.com> <20210322105729.24rt4nwc3blipxsr@box> From: "Yu, Yu-cheng" Message-ID: <4b926140-66ac-f538-df94-8213b8a2ab86@intel.com> Date: Fri, 26 Mar 2021 08:46:30 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210322105729.24rt4nwc3blipxsr@box> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/22/2021 3:57 AM, Kirill A. Shutemov wrote: > On Tue, Mar 16, 2021 at 08:10:44AM -0700, Yu-cheng Yu wrote: >> Account shadow stack pages to stack memory. >> >> Signed-off-by: Yu-cheng Yu >> Reviewed-by: Kees Cook >> --- >> arch/x86/mm/pgtable.c | 7 +++++++ >> include/linux/pgtable.h | 11 +++++++++++ >> mm/mmap.c | 5 +++++ >> 3 files changed, 23 insertions(+) >> >> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c >> index 0f4fbf51a9fc..948d28c29964 100644 >> --- a/arch/x86/mm/pgtable.c >> +++ b/arch/x86/mm/pgtable.c >> @@ -895,3 +895,10 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) >> >> #endif /* CONFIG_X86_64 */ >> #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ >> + >> +#ifdef CONFIG_ARCH_HAS_SHADOW_STACK >> +bool arch_shadow_stack_mapping(vm_flags_t vm_flags) >> +{ >> + return (vm_flags & VM_SHSTK); >> +} >> +#endif >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >> index cbd98484c4f1..487c08df4365 100644 >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -1470,6 +1470,17 @@ static inline pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma >> #endif /* CONFIG_ARCH_MAYBE_MKWRITE */ >> #endif /* CONFIG_MMU */ >> >> +#ifdef CONFIG_MMU >> +#ifdef CONFIG_ARCH_HAS_SHADOW_STACK >> +bool arch_shadow_stack_mapping(vm_flags_t vm_flags); >> +#else >> +static inline bool arch_shadow_stack_mapping(vm_flags_t vm_flags) >> +{ >> + return false; >> +} >> +#endif /* CONFIG_ARCH_HAS_SHADOW_STACK */ >> +#endif /* CONFIG_MMU */ >> + >> /* >> * Architecture PAGE_KERNEL_* fallbacks >> * >> diff --git a/mm/mmap.c b/mm/mmap.c >> index 3f287599a7a3..2ac67882ace2 100644 >> --- a/mm/mmap.c >> +++ b/mm/mmap.c >> @@ -1718,6 +1718,9 @@ static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) >> if (file && is_file_hugepages(file)) >> return 0; >> >> + if (arch_shadow_stack_mapping(vm_flags)) >> + return 1; >> + > > What's wrong with testing (vm_flags & VM_SHSTK) here? VM_SHSTK is 0 on > non-x86. > >> return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; >> } >> >> @@ -3387,6 +3390,8 @@ void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) >> mm->stack_vm += npages; >> else if (is_data_mapping(flags)) >> mm->data_vm += npages; >> + else if (arch_shadow_stack_mapping(flags)) >> + mm->stack_vm += npages; > > Ditto. > The thought was, here all testings are done with helpers, e.g. is_data_mapping(), so creating a helper for shadow stack is more inline with the existing code. Or, maybe we can call it is_shadow_stack_mapping()? And, since we have a helper, use it in accountable_mapping() as well. Or do you have other suggestions? Thanks, Yu-cheng