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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 83F89C433DF for ; Tue, 16 Jun 2020 07:56:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FB3C2074D for ; Tue, 16 Jun 2020 07:56:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dUudr8te" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727115AbgFPH4Y (ORCPT ); Tue, 16 Jun 2020 03:56:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726526AbgFPH4A (ORCPT ); Tue, 16 Jun 2020 03:56:00 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FCE6C05BD43 for ; Tue, 16 Jun 2020 00:56:00 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id h95so1165860pje.4 for ; Tue, 16 Jun 2020 00:56:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=8oQ1io/qQi+y3itntJsBYA2dRhXjx47tAO/g5lp+Xfc=; b=dUudr8tehj5H24uL5Ho0iwb+sZ5G6JJdKuZ/zEFCnEYnP0ATralz+E+Z8at+Z8YTJh ROT3Vnf0VnaKvwVQY2AdbYf9YmGavQkooUekLQkRuZykW0uHVxr4fC+R8O9NAHTympvy C1zyK5SJO9VhTxh5y3BLeq0yb3AnXqjj0dJmSvT+gpdYtVoXxG2fA6ZQRjyZ57VMhIWK 6kLdGdvV2+vyWs5VUAJ3tYdVeKju9EG1K4rQnQF+O3/8Vp+kSc5lm9z7SEnarZZohFIt DWl0nIOa7kJ/aODibBgLCCK2xJ1JWkFjqA3hQ1nmIWRwU2B0k1dwPECsOyq4/KcfSjJM +BTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=8oQ1io/qQi+y3itntJsBYA2dRhXjx47tAO/g5lp+Xfc=; b=K3i3JzQBhZRVe1i8Pcp4hE6Dn528DCmLchJo9SbkYPZfgj+jtAgf231C3frwT4oAR4 EKFSn7EZ/0hwzpXoi9oVMP6DLVaoUuXrtib1zz4PNBuEDrL0jGNbZT694+UANeYbxoEH FqILGxk1utBMIhkcHE5GL8ZVIgFRWw6/hcbasbLZnyZ4F5xX+kmtIfLER840EN+D26cg QJaXCkoiu3/s51KXdpe7T9DI9m6YVeBsp2KtqVb2sgtxX8zoiYy/hVjPFnWFfsa0say3 cLB8orWq1uaevP4u1P/E0wMOBTZJ0zpK4qfjlgb/wXG/o2Bb1f9fRbXIFnMvex88xBxX k7vw== X-Gm-Message-State: AOAM530ISBqkh4r5xpUiGaGbb3g1ox4sX0zm422MYrOy8d49GhkNGWnZ w/UzAqU+KT25MKP9ei+wAJ0= X-Google-Smtp-Source: ABdhPJyBbHCAFPTNgi+mnpbvSvrE+TrECh5PjtavYN/bmJ9l5eb5ApOgY5NzKWJ5Wy7Yqg/KjNDG+A== X-Received: by 2002:a17:90b:23c6:: with SMTP id md6mr1884893pjb.122.1592294159866; Tue, 16 Jun 2020 00:55:59 -0700 (PDT) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id g6sm16168984pfb.164.2020.06.16.00.55.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jun 2020 00:55:59 -0700 (PDT) From: Andrei Vagin To: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon Cc: linux-kernel@vger.kernel.org, Vincenzo Frascino , Mark Rutland , Thomas Gleixner , Dmitry Safonov , Andrei Vagin Subject: [PATCH 4/6] arm64/vdso: Handle faults on timens page Date: Tue, 16 Jun 2020 00:55:43 -0700 Message-Id: <20200616075545.312684-5-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200616075545.312684-1-avagin@gmail.com> References: <20200616075545.312684-1-avagin@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a task belongs to a time namespace then the VVAR page which contains the system wide VDSO data is replaced with a namespace specific page which has the same layout as the VVAR page. Reviewed-by: Vincenzo Frascino Reviewed-by: Dmitry Safonov Signed-off-by: Andrei Vagin --- arch/arm64/kernel/vdso.c | 57 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 53 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 14d5b7642b62..21bdd0d74f40 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -166,15 +167,63 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) mmap_write_unlock(mm); return 0; } + +static struct page *find_timens_vvar_page(struct vm_area_struct *vma) +{ + if (likely(vma->vm_mm == current->mm)) + return current->nsproxy->time_ns->vvar_page; + + /* + * VM_PFNMAP | VM_IO protect .fault() handler from being called + * through interfaces like /proc/$pid/mem or + * process_vm_{readv,writev}() as long as there's no .access() + * in special_mapping_vmops(). + * For more details check_vma_flags() and __access_remote_vm() + */ + + WARN(1, "vvar_page accessed remotely"); + + return NULL; +} +#else +static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma) +{ + return NULL; +} #endif static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { - if (vmf->pgoff == 0) - return vmf_insert_pfn(vma, vmf->address, - sym_to_pfn(vdso_data)); - return VM_FAULT_SIGBUS; + struct page *timens_page = find_timens_vvar_page(vma); + unsigned long pfn; + + switch (vmf->pgoff) { + case VVAR_DATA_PAGE_OFFSET: + if (timens_page) + pfn = page_to_pfn(timens_page); + else + pfn = sym_to_pfn(vdso_data); + break; +#ifdef CONFIG_TIME_NS + case VVAR_TIMENS_PAGE_OFFSET: + /* + * If a task belongs to a time namespace then a namespace + * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and + * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET + * offset. + * See also the comment near timens_setup_vdso_data(). + */ + if (!timens_page) + return VM_FAULT_SIGBUS; + pfn = sym_to_pfn(vdso_data); + break; +#endif /* CONFIG_TIME_NS */ + default: + return VM_FAULT_SIGBUS; + } + + return vmf_insert_pfn(vma, vmf->address, pfn); } static int __setup_additional_pages(enum vdso_abi abi, -- 2.24.1