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=-8.8 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,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 1F55DC31E46 for ; Wed, 12 Jun 2019 19:27:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB7F521721 for ; Wed, 12 Jun 2019 19:27:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="cP3ve+V2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728921AbfFLT05 (ORCPT ); Wed, 12 Jun 2019 15:26:57 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:38107 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728677AbfFLT0v (ORCPT ); Wed, 12 Jun 2019 15:26:51 -0400 Received: by mail-wr1-f68.google.com with SMTP id d18so18129835wrs.5 for ; Wed, 12 Jun 2019 12:26:49 -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=4nDl/CUmCqqh37N3cXS8r+aNsaHvCoXX3q5gpIkIcXw=; b=cP3ve+V2cqLDHqdmmZWEIRkLThECV8dV9CpQoJNIPFK0OOyl/ECobu8g3pVyvDlF/5 N75tP0MJFDZSkg+g0Shq9KGffobsEPGgPJk11TBMBvqgLSYNqFDaW4asBO2bzEQqYn4Q aboNx7HWRw1FAXssQZ2KToQglqdWfu/Zy6LJqzbTQVUn5GBTfKW5q4ZoOo+KfSj2fgDm FehmyhHpObVdhb7DKtYfbdJ8BtyNp9ccDg6GkgIbxSd7su5z0qXpRHf/rTftjbH+mNaO XLQ+vggFv8tm6QMbsuOqCXaCX85efXP2r8VMLnArHWepTMd7UJhqN4A+oNNaGUMSQgQr 4tAQ== 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=4nDl/CUmCqqh37N3cXS8r+aNsaHvCoXX3q5gpIkIcXw=; b=YrGGw/UEN5s4b0d4IOqb8YMbQrRekD8kt1rIq4EC3Dnzx54kvOd+xzKcdWLUFDHOH/ EpQNaVP8loQOQaG95R6cmiABbdI9ttCmqfWttxBxovraI0RRNCf4zSTdvXvc4NKVHB+j pmbqIJlAL1dkL7MjN0AWSXiVrAFvm1loOOQ2wR4ZHAvmzj97ez2a/+wS2es7v7X6xAko vxPVR4j4wbwkVnCSijo9BzV6/Y1ljrnvcah/gFjyojg2lApKSUcmAT+uFH0mEjeJZCqg 4skuG2s1QtvYf8RhStYhWC3jzgw5dMgix/GEaLH1DhjgiXvtuyn4o+tUjO8XX0bqnTSw WIBQ== X-Gm-Message-State: APjAAAVEvenmLvioyTMgSmLkgaERrkloOJBGxnGdP+j1gpyqQR52fOY3 6445ymX79HwTNsaKWckHQvNgbEp5kXQ= X-Google-Smtp-Source: APXvYqzvFvZKw4czh3fj4IC0HCIsTNt0UN8B6+q4hgTO1PoZvnQtXhK6OsfwFtRQLTAdWfRhowlMWg== X-Received: by 2002:a5d:4f8b:: with SMTP id d11mr19501473wru.264.1560367608606; Wed, 12 Jun 2019 12:26:48 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id r5sm612526wrg.10.2019.06.12.12.26.47 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 12 Jun 2019 12:26:48 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov , Adrian Reber , Andrei Vagin , Andy Lutomirski , Arnd Bergmann , Christian Brauner , Cyrill Gorcunov , Dmitry Safonov <0x7f454c46@gmail.com>, "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: [PATCHv4 13/28] x86/vdso: Restrict splitting VVAR VMA Date: Wed, 12 Jun 2019 20:26:12 +0100 Message-Id: <20190612192628.23797-14-dima@arista.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190612192628.23797-1-dima@arista.com> References: <20190612192628.23797-1-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 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 8db1f594e8b1..d2b421233ba5 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