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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 55432C282CB for ; Wed, 6 Feb 2019 00:12:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 199ED218C3 for ; Wed, 6 Feb 2019 00:12:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="nVR/+W7A" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729821AbfBFAMF (ORCPT ); Tue, 5 Feb 2019 19:12:05 -0500 Received: from mail-ed1-f65.google.com ([209.85.208.65]:39676 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729633AbfBFALy (ORCPT ); Tue, 5 Feb 2019 19:11:54 -0500 Received: by mail-ed1-f65.google.com with SMTP id b14so4467526edt.6 for ; Tue, 05 Feb 2019 16:11:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=EO+RYEcmpOreznGDDZGCoO864712k1v0HTv9EOfb/gA=; b=nVR/+W7APlED/5oXx5iqB73rglfVteAO0hCyxfqSpA0vLRvEFdE9MrkUcchQwhD3Ki KCX1adhmwAiEIs/QDlTq6DAoeciNKFXs0m/zQuyhRYJGTMjhHVvLzzxQfcQYNZnLzFHX yC0ErFLMt+qtbT79BhbIZZ/SWqpMbSfjBWuBsI3ONRRwSOIhAgosso/t84B5z2wrS3OH NuSHedhQq4d8y/H1KMtEtc8w6axVhOb53OVYU+CXDsAiraqQplGpuHjuq8RJYzcd+B/Z LqJ3Tlkc7IyNraKWHCeSeAHAJ6MK1OG8cusFQNYqElUP1vUPs3c/CaUXXRNQL3wLeOW5 TJMQ== 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:mime-version:content-transfer-encoding; bh=EO+RYEcmpOreznGDDZGCoO864712k1v0HTv9EOfb/gA=; b=ZtgrGFj9soFiCTMGT+XkD/VPhMgu8sIcvXPmJYVO1NiS//htfX4RkC7ZKv9Lz1WBuQ cHRVgDHd2vlauugXt1xfxv2/J+WVa3PxRcW5A+rg5thw1rCh9tGBu/SjxMV2eSARRMmx LcyaSgksVsW1BJWrj0QMPTjqijlyBqz1Qq9btt/UX/4v3M1TSSJX90jpTyJXdouJuhgn AvmDRB1KiqVx5wFT9AG2ndQsMi6uBz3cxl4Ood+033q9H9Qv5laVGepdHYRwgqalN/bU xy+2SylzAYwJgovPEFEWqrtJOMfzrPPxk8/xzGWpjvIJTdjlfT3rgpO0ZTBtLMZ+dpvI 2ZOA== X-Gm-Message-State: AHQUAuaZisg2UWqER7ZBgb0iF0k32BoJgkfzFh9FC7dig5K6J58IkmYT UlXM0dWgv/AYucLZmUUe/sFB8+32xuA= X-Google-Smtp-Source: AHgI3IZd715GY7oV9JLOUm2wksZ4xWMmA+plHuBx//m/bbIEqQqD9QE3WYssK/bX0U2oxPG6vMR7iw== X-Received: by 2002:a50:ec19:: with SMTP id g25mr5907076edr.38.1549411912433; Tue, 05 Feb 2019 16:11:52 -0800 (PST) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id p30sm5489594eda.68.2019.02.05.16.11.51 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 05 Feb 2019 16:11:51 -0800 (PST) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov , Adrian Reber , Andrei Vagin , Andrei Vagin , Andy Lutomirski , Andy Tucker , Arnd Bergmann , Christian Brauner , Cyrill Gorcunov , Dmitry Safonov <0x7f454c46@gmail.com>, "Eric W. Biederman" , "H. Peter Anvin" , Ingo Molnar , Jeff Dike , Oleg Nesterov , Pavel Emelyanov , Shuah Khan , Thomas Gleixner , containers@lists.linux-foundation.org, criu@openvz.org, linux-api@vger.kernel.org, x86@kernel.org Subject: [PATCH 32/32] x86/vdso: Restrict splitting VVAR VMA Date: Wed, 6 Feb 2019 00:11:06 +0000 Message-Id: <20190206001107.16488-33-dima@arista.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190206001107.16488-1-dima@arista.com> References: <20190206001107.16488-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Although, time namespace can work with VVAR VMA split, it seems worth to forbid splitting VVAR resulting in stricter ABI and reducing amount of corner-cases to consider while working further on VDSO. I don't think there is any use-case for partial mremap() of vvar, but it there is - this patch can be easily dropped. Signed-off-by: Dmitry Safonov --- arch/x86/entry/vdso/vma.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index 52c1e4c24455..dc1fca4d935a 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -87,6 +87,18 @@ static int vdso_mremap(const struct vm_special_mapping *sm, return 0; } +static int vvar_mremap(const struct vm_special_mapping *sm, + struct vm_area_struct *new_vma) +{ + unsigned long new_size = new_vma->vm_end - new_vma->vm_start; + const struct vdso_image *image = current->mm->context.vdso_image; + + if (new_size != -image->sym_vvar_start) + return -EINVAL; + + return 0; +} + static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { @@ -149,6 +161,7 @@ static const struct vm_special_mapping vdso_mapping = { static const struct vm_special_mapping vvar_mapping = { .name = "[vvar]", .fault = vvar_fault, + .mremap = vvar_mremap, }; #ifdef CONFIG_TIME_NS -- 2.20.1