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 F3879C2D0EF for ; Thu, 16 Apr 2020 05:27:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D454D2076A for ; Thu, 16 Apr 2020 05:27:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ki4VmJyQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406672AbgDPF1W (ORCPT ); Thu, 16 Apr 2020 01:27:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2406491AbgDPF0r (ORCPT ); Thu, 16 Apr 2020 01:26:47 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D2BBC061A0F for ; Wed, 15 Apr 2020 22:26:47 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id a32so865656pje.5 for ; Wed, 15 Apr 2020 22:26:47 -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=HkFB2IFB6eu4Qsibzpvaj5eV40S/BQoyfyZyOgKqRdU=; b=Ki4VmJyQMAakb5h1e5GCup2A4dLJWYNrW9MVsygLyscRN0NtUNWyro1UJ79U6GamhL wCx0wQUMRrNE+eoV514UXPJfpSWfXwd/3IHLfUk7UWgk8sO0sytG8qn9wMNCphu5wfoA j8s/9IqOnvtdc3P7CFy4kIIh1PUcLynMIEp7OJR0DVd8pp4f+MPRtnxtR5va94odSYpX yG+5UUBFUvYTREJAAkL8dHdRh4P+ezpXrpSV6EMhdTIK779brbdv0TyVZT7Xs0Zh7uA+ e0GzurT7JqT08V+9p9slejCqK9EsZHcZH7RkNygBLU+Mw0QM+4veSdGqdPob9bxI2R0a feNQ== 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=HkFB2IFB6eu4Qsibzpvaj5eV40S/BQoyfyZyOgKqRdU=; b=HaqnlZxIXHxOHW8w6m8Y2lhh01KDJ7raomKsXL6JJKugzv8aPWQ8BjUSNb06SqQvzq rij4d/lT9iefvhNQKR25pEofMV4GUKfFRMNApb4ZhTZ7DzTSS2dNnP3h8qyHLA8762um PPZfyoFxZZIh5nKuxg62CEugk3CJdyQA98oPM4/Q6gAqq74i1t14iXi/5JdoCY55ehAD 5pJ2VtwhxGpSZarGo5zl/DWOhS027l02VHd3jBV2MSiZ363EsdYtKJSBe1UZicmc4+pu C27eZgnPsEWLQXrZpOIdX+4qDSgz+FnHohBzIcDmw1U0prmit8g6Ty+FIHc2S8gF9m3S qIxQ== X-Gm-Message-State: AGi0PuZO0EsWuTvwQTF3tWvPuVxjRoxkEK+gnpC3hbZDXaKZOOX3tJXI ZZtiGzL3TAJATZdm49GKItQ= X-Google-Smtp-Source: APiQypJl6jnFydHzld8Y6PdrjF3ChQCmvwCzlPXym6IsyBAFXmPGRV+0P3/LzKyTAxQ+iI6harv6Sw== X-Received: by 2002:a17:90b:19c9:: with SMTP id nm9mr3171152pjb.86.1587014806945; Wed, 15 Apr 2020 22:26:46 -0700 (PDT) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id c21sm53699pjr.2.2020.04.15.22.26.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2020 22:26:46 -0700 (PDT) From: Andrei Vagin To: Vincenzo Frascino , Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Rutland , Thomas Gleixner , Andrei Vagin , Dmitry Safonov Subject: [PATCH 4/6] arm64/vdso: Handle faults on timens page Date: Wed, 15 Apr 2020 22:26:16 -0700 Message-Id: <20200416052618.804515-5-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200416052618.804515-1-avagin@gmail.com> References: <20200416052618.804515-1-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 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 b3e7ce24e59b..fb32c6f76078 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -175,15 +176,63 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) up_write(&mm->mmap_sem); 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 arch_vdso_type arch_index, -- 2.24.1