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 E8524C433E0 for ; Tue, 2 Jun 2020 18:03:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B95EC2074B for ; Tue, 2 Jun 2020 18:03:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qUzo7Htw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728170AbgFBSD0 (ORCPT ); Tue, 2 Jun 2020 14:03:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727032AbgFBSDJ (ORCPT ); Tue, 2 Jun 2020 14:03:09 -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 A04BDC05BD1E for ; Tue, 2 Jun 2020 11:03:09 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id m2so1891132pjv.2 for ; Tue, 02 Jun 2020 11:03:09 -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=pYFSYa09zr69QLygLryWctXuj1LoNkWSXD+By1jBPHc=; b=qUzo7Htwnb4o/U1sPEPo4n59Pz3Gtet9GVRwIWHj4yKj32lDKLpkIsyWwQoKDckgvG NmiwHf2CfErIQV1ueag5uXysuSiioBL1K6cEa3SgbGK78JP6epci1KgN3YtHfrmu8G2z N7OsYPi51MCqlo90TkS6jvxrR2rFemS0JNaouPfAvUhkUi/4vohLB5ObkRxa/tXAHztv klV/C53z0G+2BW8UCmKjP5MYHdv/aQRSLi9xQLsjw5/RewsZoERNtFX3E0k+TX4ue6M/ uYNwi9f/Vi3XXbl2+hKrlyd/Bwgb8sysAZCgF6lEKw3LuXKwg9dtIQNloUZ2sMTiRy67 w6zw== 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=pYFSYa09zr69QLygLryWctXuj1LoNkWSXD+By1jBPHc=; b=OZdhaMu7Ihh12vbqaA45Xt0adMLW2UMwUKmWjSu9rmvtJcGlbDnB8tOQVdgoXQaBLw uLJgIDbRdnlCOAwfEY2K5Z0jGu30KYqd9vR9dyku0t3ky2CuvfLZ7zgnJE95mnh+M7v6 7610XptMs5W1pzZk3RSmu8QdNEWZEmzypbHbM91+afoPSOMJXilMJU+dQ2yvlxDpKYJl CvS6jmgD+8SwSjQCBhsZrFbXIStywtXHC/045X/wBleFgkyxXnfkm7KDt8XsAJI7+EMC sK82ehWbMuUeFaWN4+/ue+f5mRRhi1cDh9qMBIW1AfB39IfKC4WqDCzGKw+EbRherinE SjLg== X-Gm-Message-State: AOAM533HxhBGmONr3j5rQvsIQU4WUBs/eyv7scYoFdBd0ukmTJ1q0Bxj KXDtr5Q5psyIsqJXnosV6eM= X-Google-Smtp-Source: ABdhPJxjq8mzXPifWl0Kc+KsV7By219qzUuO5Tzse7+mioUC3UiBfTQEoYr22AavOCwIwF9ZYEIRTQ== X-Received: by 2002:a17:90a:ce05:: with SMTP id f5mr449132pju.32.1591120988929; Tue, 02 Jun 2020 11:03:08 -0700 (PDT) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id p8sm2740053pgs.29.2020.06.02.11.03.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 11:03:08 -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, 2 Jun 2020 11:02:57 -0700 Message-Id: <20200602180259.76361-5-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200602180259.76361-1-avagin@gmail.com> References: <20200602180259.76361-1-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 1fa6f9362e56..f3baecd8edfb 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