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=-9.8 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,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 E4C65C35DF8 for ; Tue, 25 Feb 2020 07:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB0CA21744 for ; Tue, 25 Feb 2020 07:37:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bG7g6CDS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729505AbgBYHhu (ORCPT ); Tue, 25 Feb 2020 02:37:50 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:46674 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729409AbgBYHhq (ORCPT ); Tue, 25 Feb 2020 02:37:46 -0500 Received: by mail-pf1-f194.google.com with SMTP id k29so6700171pfp.13 for ; Mon, 24 Feb 2020 23:37:46 -0800 (PST) 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=sg/RdX3cnApG8KxqkYoz0JziOI+7hxQWlWjP9QA0+OY=; b=bG7g6CDSIPw+Dm3VI7iFviDISIYyxvfWj9Pl0agk37XSxmqnG5rCsKwBuWfymVraGU ssayjkKy90mnHv3wWpqR83zu96CHiZ+mWnq2iNOwaLTsqEW42Xp09oSLJ81Eh8i0mKLF fnEgZBf9486TV3tvM0zhksBqUE6skHGPmHY/7a5odVG/1w6Iw1IZMuPQgfblaq3iTLJ7 x+VPSOq8x2HtpbZkWbFJ4ObJz/8hp5HwNRf6u4IU8feZhQOx194ntqH37grqvXpAE8PX Coj8g8QfWtcOF5ES/1p+ZzXeFkLbfR/9tBD+8/RbgFYWdzZPjjLK02GlcEuP0XcvqKHY z8lw== 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=sg/RdX3cnApG8KxqkYoz0JziOI+7hxQWlWjP9QA0+OY=; b=b0P8xmgOF4PRfcN7YO+BZPd5Gv0jXGC8E/sv7Duq9PgjI7aUGPGhr3bv2DTrHoslp7 1FGCoSSN4ZmhqaH0Oo5X6LPfwXeaEM4uWRI0OTELxC37GC7tQf+l5ho5iJiajBTZFjwG QRj7ztuNP/zQHkMVDzJdAMrS7bfV5PAJKk507GL082/KEoSQdClOGT/3AqFIDmkjX1v9 r0Hxbgy7/w28XClXM4/7SFYvSA7jjGLqtkYM7hjI4aD1qUCADwNfY0/USqWJ5ynla6GW H8FA6HmROmii5g+66wwd9O7WDpQtqcXNlPzmwt2lvFSVPGdQI/3FIS0WbpabFFBbS/7Y Jwvw== X-Gm-Message-State: APjAAAXpVNLUWKgOOrEUrqh71w4lmDLzI+l3ZI6zoEpkxy66NfhSirCF SiAfIZiPO24/j+DCBzn9nuA= X-Google-Smtp-Source: APXvYqxIsjWOLBzTKLNKC3BCo8OjuyQYteq3bx+WPxxZJOKSjwatxv3mV1yfko8OVrPQEAf5RqkS6A== X-Received: by 2002:a63:fe4f:: with SMTP id x15mr58115551pgj.30.1582616264731; Mon, 24 Feb 2020 23:37:44 -0800 (PST) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id m128sm15979390pfm.183.2020.02.24.23.37.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Feb 2020 23:37:44 -0800 (PST) From: Andrei Vagin To: Vincenzo Frascino Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Andrei Vagin , Thomas Gleixner , Dmitry Safonov Subject: [PATCH v2 4/6] arm64/vdso: Handle faults on timens page Date: Mon, 24 Feb 2020 23:37:29 -0800 Message-Id: <20200225073731.465270-5-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200225073731.465270-1-avagin@gmail.com> References: <20200225073731.465270-1-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. 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 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=-9.7 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,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=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 31A72C35DFA for ; Tue, 25 Feb 2020 07:38:57 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E039E21927 for ; 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Mon, 24 Feb 2020 23:37:44 -0800 (PST) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id m128sm15979390pfm.183.2020.02.24.23.37.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Feb 2020 23:37:44 -0800 (PST) From: Andrei Vagin To: Vincenzo Frascino Subject: [PATCH v2 4/6] arm64/vdso: Handle faults on timens page Date: Mon, 24 Feb 2020 23:37:29 -0800 Message-Id: <20200225073731.465270-5-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200225073731.465270-1-avagin@gmail.com> References: <20200225073731.465270-1-avagin@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200224_233746_249568_24EE4E85 X-CRM114-Status: GOOD ( 15.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Gleixner , Andrei Vagin , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Dmitry Safonov MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.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. 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel