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 511DBC35DF5 for ; Tue, 25 Feb 2020 07:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26F4D21744 for ; Tue, 25 Feb 2020 07:37:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hF+L0SkX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729443AbgBYHhp (ORCPT ); Tue, 25 Feb 2020 02:37:45 -0500 Received: from mail-pj1-f68.google.com ([209.85.216.68]:51562 "EHLO mail-pj1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729317AbgBYHhm (ORCPT ); Tue, 25 Feb 2020 02:37:42 -0500 Received: by mail-pj1-f68.google.com with SMTP id fa20so884936pjb.1 for ; Mon, 24 Feb 2020 23:37:42 -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=AkyLcT/M41H8pNXfB2E+BzqT+C+wAkbHPxgbVN+0zTc=; b=hF+L0SkX3QFj58j9vqoEJ6IjIYswDgAEBWiesoy+sopgxymcU+R/Q2leded9N+UiPA yLatd1d8S25usCpHooLBktyUToJ6eO0zSHRZzBlsSzsunV4XlcRcGT0cIKFD3nSRfKRA hipJWwUyXC+TViT9VcLD5RfONN7yAKMnvq67oknJIIqp85Vjf9rRN00+pt2KGDF2MbX3 4c2AS/WkRmpUJLcqnV5MFTtxJbVPA1SM/u1fgEFN8ngV5GbrP8Ta+3zhKlv449eH4MO6 3Ri631Htals7fy2Oh4T/voA6GGp3QfuJ+uNLmwjxjsuMRgeetUxhrk4ctpQJvmQJOSOo 0cLQ== 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=AkyLcT/M41H8pNXfB2E+BzqT+C+wAkbHPxgbVN+0zTc=; b=T1lgeE0pu2zB60k8CEdbBur+b8GnI+jNXtw/zIilXi7mm5Pf/fqtyBSjW3/UlmxGQl Gn3QC+JGj99wlGotzvVoZX21oTSoJ3wIGBVm8+VO0+9D1/hRTxoBBqaCJc2MiI8IR7Bg jcU+Rb74FOL/A2d2BWYKF10TUO5WsKrrQyUHj3iWKnkPbYPQAAObyLGN3Lzdl7TincGF 3r7Wq4qUkVB9pbPMOfoRtaqn4HSUI9HIgGaucDIXD4cr6UUhfplPlTJP4tKeKVPUvY06 P6NvyaH5SCfoNSSBo0U+xCExFlIk6qdejfRMONpAJXk5P1cPV3laoPZGgS+n6SmyKgxP 1viQ== X-Gm-Message-State: APjAAAVrIAOQUqgkZjuKExl4Ht1ziu5QYWKMgXZ/o73s/KX10vOb368S 2o5uefzRprNIfX8FcFOvXco= X-Google-Smtp-Source: APXvYqwnmes/Pi/02QPjNqcbuZoJp4CZnWoJVVApGWQqfgKMt8MSEPCZzU8aeC8A78O3AeoOmzvmhQ== X-Received: by 2002:a17:902:9308:: with SMTP id bc8mr55796788plb.268.1582616262049; Mon, 24 Feb 2020 23:37:42 -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.183.2020.02.24.23.37.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Feb 2020 23:37:41 -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 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Date: Mon, 24 Feb 2020 23:37:27 -0800 Message-Id: <20200225073731.465270-3-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 The VVAR page layout depends on whether a task belongs to the root or non-root time namespace. Whenever a task changes its namespace, the VVAR page tables are cleared and then they will be re-faulted with a corresponding layout. Signed-off-by: Andrei Vagin --- arch/arm64/kernel/vdso.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 290c36d74e03..6ac9cdeac5be 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -131,6 +131,38 @@ static int __vdso_init(enum arch_vdso_type arch_index) return 0; } +#ifdef CONFIG_TIME_NS +/* + * The vvar page layout depends on whether a task belongs to the root or + * non-root time namespace. Whenever a task changes its namespace, the VVAR + * page tables are cleared and then they will re-faulted with a + * corresponding layout. + * See also the comment near timens_setup_vdso_data() for details. + */ +int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) +{ + struct mm_struct *mm = task->mm; + struct vm_area_struct *vma; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + unsigned long size = vma->vm_end - vma->vm_start; + + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO].dm)) + zap_page_range(vma, vma->vm_start, size); +#ifdef CONFIG_COMPAT_VDSO + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO32].dm)) + zap_page_range(vma, vma->vm_start, size); +#endif + } + + up_write(&mm->mmap_sem); + return 0; +} +#endif + static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { -- 2.24.1