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,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 CFA58C43218 for ; Thu, 25 Apr 2019 16:16:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2BB082088F for ; Thu, 25 Apr 2019 16:16:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="cJvEYsza" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729537AbfDYQQD (ORCPT ); Thu, 25 Apr 2019 12:16:03 -0400 Received: from mail-ed1-f68.google.com ([209.85.208.68]:45314 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728042AbfDYQOk (ORCPT ); Thu, 25 Apr 2019 12:14:40 -0400 Received: by mail-ed1-f68.google.com with SMTP id k92so357691edc.12 for ; Thu, 25 Apr 2019 09:14:38 -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=1GCSKX7upO4gUgT9jk4Ocxz37wBs1AXvqHFgAl4OIuk=; b=cJvEYszaGplcwVA5aahxPz4GGTcpMWGKC968tGMzmcc7A0Ms+FCFpqJZkyQ7jHsafP pOjFMrefd42+QX/YQw3Ox08ANxB1ITN/SdFQ+Onl3n/wtllW4kMXzpV2t/UB/YAjv7HT BHJBflC1UHwuqwJR9wAZ1W/E9mqECAQtXgjzyLwQeOrSifkc5ta7v7tyRy4l5t8RCFvx wLuy/Z1erCISaBfgOjm8kII6ukjmcuEExynn0EF8ctW5Qxlx6udO/RUJnRX0EQELqrgU zuQfwisQvaYhuWwgtwbKYIrG/nNC6h9Yl+kQZtHTyNjYHvA8y6Xw9CqUygRlOJB9N/xn 7icQ== 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=1GCSKX7upO4gUgT9jk4Ocxz37wBs1AXvqHFgAl4OIuk=; b=gFoNrlCQKJZrW8a63XDxUMQRhBdjhnFZ47PZ+YYmzvioTnjf0EzpEfxTUQl1oE9bdB 3PYAjT6AvwJHEFi4atAd0HL/NzfVxV1LNCv2hPgLYJlrEvoPMsR62UT4e95e2+E0hj/b U7iag6DtJNufH/KBsZDse9pgwDfk3EwAszUZaM88Z4i68c6VTBw0a84LGrDiknNMuLYx Cyg8TwMaS3xvkVpKRqdMpoT1e8Gu2BsmrDm8TCQnftXjgt7wkxR13082eNdvco+I4/YU AnLZHTWRf+0xlj1aU3Z0del00oEowtNJUGGpVHcd5N6ftEtRJlEZUG4NDfUdkOSlIHa8 bpsw== X-Gm-Message-State: APjAAAVipu4c5MQhDAF9yg+A9xz58mp7ol9p2Lh65xtbFhjySytiOGJS yT2VfuIL8AccGrrtnkSOkGBmmjZDDpE= X-Google-Smtp-Source: APXvYqwxkEdXinZTG5bgJ+JaRkll5OK0VSmx+8Dk3imUTlO1TJjYDhn5gWAltymTOjvHCprPimyHIw== X-Received: by 2002:a17:906:498b:: with SMTP id p11mr20067751eju.119.1556208878132; Thu, 25 Apr 2019 09:14:38 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id br19sm4147042ejb.48.2019.04.25.09.14.36 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 25 Apr 2019 09:14:37 -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 , 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: [PATCHv3 12/27] x86/vdso: Restrict splitting VVAR VMA Date: Thu, 25 Apr 2019 17:14:01 +0100 Message-Id: <20190425161416.26600-13-dima@arista.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190425161416.26600-1-dima@arista.com> References: <20190425161416.26600-1-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. 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 babc4e7a519c..ff9875a4d53b 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 = 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) { @@ -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, }; /* -- 2.21.0