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=-9.9 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_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 4E935C76186 for ; Mon, 29 Jul 2019 21:58:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21AFB216C8 for ; Mon, 29 Jul 2019 21:58:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="K3YZLTWn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730372AbfG2V6e (ORCPT ); Mon, 29 Jul 2019 17:58:34 -0400 Received: from mail-wm1-f67.google.com ([209.85.128.67]:39677 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730318AbfG2V6b (ORCPT ); Mon, 29 Jul 2019 17:58:31 -0400 Received: by mail-wm1-f67.google.com with SMTP id u25so44435778wmc.4 for ; Mon, 29 Jul 2019 14:58:30 -0700 (PDT) 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=3MjEHvnSKKqtqfjPruFAI4NMd2j71wVzmmWx9wAlQuc=; b=K3YZLTWnOhf9uJPUr1iQ87BSk5m9pfk0LQyZSfVvG/3zHnum6jcfJs/niIFFRVn7Wk ZyiuRJE0z3pZSrJZnl3vJoU7znYGhcJZU016YnXI5L8d9FBV5wqmKUDLVJGnNlshvmU6 ln5pxw4cUpvOEp2RAoz2B85ngRKuO/0iRLtUsRDz9uUnjdciIXp7L9Fchfdu2ip6BT5H Gt0iObe/GQoNpJjwmZBroAmMmOcGibN5hPgsQkiqsbGb0x71aexNdlve45nROsPPgSla TSDYviucQQHMJ+z+AvlR1at+BZFIausmWWI55UK9BTk8jaJmJiW40eFE/R9gldOycy2s qJ4Q== 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=3MjEHvnSKKqtqfjPruFAI4NMd2j71wVzmmWx9wAlQuc=; b=nkDxmyc6iVAhPezzb8Iz59pfbbARypGUPCRo+DFoowrdjLluhj+oZvZgdNG46tFTvJ eF6IlUqTqN3+u3pMqzU+U1BTXooAn792wab/6vNxoBqstqeM5LbPAoAqnlopl4o9BoP4 yUosT4zG2Z94aICeeiHLlGNoHCkHEcVjf74/cOm1p068mF3QdXbnpm6fkfDaEHP7o07R EqawWLEuYL0TMquOiiv8lSFVVbOgcyOvf7S4xAZFDbT8HjE2SIOSmsL9V8PYdlp+kP4Q 6RhbWxDNfWRQ33k8kAxWFEhr8sH+yixN1sldXjQcF1LdBOUCshoR1i8GborDfzdhfwcZ yfUQ== X-Gm-Message-State: APjAAAVp+T+SD70gNNAduCHTpccxXHGkVU41S2TJ7kxjfUVtQw62/gVR 6miC72emmnFE4jZVBibGksoDss7H9kjPW6ueg5munfqd6Oj9h02J5Oe8Ri17yXMsGxtrfW7i4hf sKdq46Nm/oaJnsa/FNlFRxMx82/nigYOj5ho1SpRDI0YrQIOcnq7mRpA10TqE9XdrX25H8EMUEB f2+Nyjfjfuoea0yztXrqZwxCpsegm2M3s3u3aEBjs= X-Google-Smtp-Source: APXvYqy+v04cNfd4RJctLqUo6ZeyXSD8ECZHh591uGR9Ntn/QZseT7nfkt1SZHQmdPRXi4AKP1fgPg== X-Received: by 2002:a1c:6555:: with SMTP id z82mr103936726wmb.129.1564437509377; Mon, 29 Jul 2019 14:58:29 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id x20sm49230728wmc.1.2019.07.29.14.58.28 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 29 Jul 2019 14:58:28 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Adrian Reber , Andrei Vagin , Andy Lutomirski , Arnd Bergmann , Christian Brauner , Cyrill Gorcunov , "Eric W. Biederman" , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Jeff Dike , Oleg Nesterov , Pavel Emelyanov , Shuah Khan , Thomas Gleixner , Vincenzo Frascino , containers@lists.linux-foundation.org, criu@openvz.org, linux-api@vger.kernel.org, x86@kernel.org Subject: [PATCHv5 21/37] x86/vdso: Restrict splitting VVAR VMA Date: Mon, 29 Jul 2019 22:57:03 +0100 Message-Id: <20190729215758.28405-22-dima@arista.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729215758.28405-1-dima@arista.com> References: <20190729215758.28405-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CLOUD-SEC-AV-Info: arista,google_mail,monitor X-CLOUD-SEC-AV-Sent: true X-Gm-Spam: 0 X-Gm-Phishy: 0 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 if there is any - this patch can be easily reverted. Co-developed-by: Andrei Vagin Signed-off-by: Andrei Vagin 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 349a61d8bf34..3f05418642a8 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -84,6 +84,18 @@ 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 = new_vma->vm_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) { @@ -136,6 +148,7 @@ static const struct vm_special_mapping vdso_mapping = { static const struct vm_special_mapping vvar_mapping = { .name = "[vvar]", .fault = vvar_fault, + .mremap = vvar_mremap, }; /* -- 2.22.0