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=-9.6 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,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 0C7ECC433DF for ; Tue, 2 Jun 2020 18:03:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBC2A20823 for ; Tue, 2 Jun 2020 18:03:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Pz2n9CXw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728101AbgFBSDV (ORCPT ); Tue, 2 Jun 2020 14:03:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727813AbgFBSDL (ORCPT ); Tue, 2 Jun 2020 14:03:11 -0400 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B46D9C08C5C0 for ; Tue, 2 Jun 2020 11:03:10 -0700 (PDT) Received: by mail-pf1-x442.google.com with SMTP id x207so3543194pfc.5 for ; Tue, 02 Jun 2020 11:03:10 -0700 (PDT) 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=0ff3kXbnY7mWoXT4ZLxtxnZ86nFn96gKFYgcZDXTiq4=; b=Pz2n9CXwBlKq8PW7Clg8W4f/AinwzKiB+1ZAHlMPryHhTCOrwPxRw4xVn3lGiwP8rO EcVeshytONp7z69W8S2CQ/9E/fSe+hmf2Z+RUjSkLQz7o7Je/OpRWCUiJFidLTEf/kI1 HZ/ShoxY8TiY8m2yA9q9zGz+Cdquf+8PmU6BnRrc2isbe6OuPXiIXLqKTluopPjOB4at 6c7Na0whmCZlO0YLC5QQgO3pGzF7cayFsq8ux4P796I2iaww5Xq+AnZdgzfmm7AOePfU UDkwsZ7Vn3XHjJ24T1QpIReFhzDhACVocPW5v4E39Dr4+3ynDwFfw5VGhylX6N9+y5zU UasQ== 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=0ff3kXbnY7mWoXT4ZLxtxnZ86nFn96gKFYgcZDXTiq4=; b=ZbcLXyOlcivkbThq70h/J8jrhSp3acJ7jRi4Td7Op6GBk/x0LlSnXDunX87NFq3cuD 5IQlqzByeaRz+avpeheSBQJiIbJaJO9QvnfGWzf/Co06unCxoM//ccRBf20KVwb7MWWh 86RfTmRSVI/aL+wNJ1B+BtVNJzmCfaVOqQrBAJy+6EcXl3F4Lo/rBoEVBiZcgq0uwNsL nQjID6MCYplu5s7Z/Qa+zNSUueY9JewmGkPO5M+CUEZ/4wkPOW01LLsobMC45LFgbmAo y8JqMajfHvohuzx0e6Dcizgbq+2nhMhSCrjyTEzMVvb2sIr5yXKnnlRmT/KzU0z0LsQO Y0MA== X-Gm-Message-State: AOAM533BIFtUeN/UK5+b2LxwLtcgHK5CLe1HVj14VxT2TBQ0kdO7DyRy JpPKhw9KIrrcBPS5KgjI/9Q= X-Google-Smtp-Source: ABdhPJyeJEHpH4P3opkCS6VQefDLqAL7wW0kPJHO1aE4Rm6Ng+v9CzZH4XZaXxORa/Ol5Hh9sA0z3Q== X-Received: by 2002:a63:9319:: with SMTP id b25mr26017714pge.374.1591120990153; Tue, 02 Jun 2020 11:03:10 -0700 (PDT) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id p8sm2740053pgs.29.2020.06.02.11.03.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 11:03:09 -0700 (PDT) From: Andrei Vagin To: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon Cc: linux-kernel@vger.kernel.org, Vincenzo Frascino , Mark Rutland , Thomas Gleixner , Dmitry Safonov , Andrei Vagin Subject: [PATCH 5/6] arm64/vdso: Restrict splitting VVAR VMA Date: Tue, 2 Jun 2020 11:02:58 -0700 Message-Id: <20200602180259.76361-6-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200602180259.76361-1-avagin@gmail.com> References: <20200602180259.76361-1-avagin@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Forbid splitting VVAR VMA resulting in a stricter ABI and reducing the amount of corner-cases to consider while working further on VDSO time namespace support. As the offset from timens to VVAR page is computed compile-time, the pages in VVAR should stay together and not being partically mremap()'ed. Reviewed-by: Vincenzo Frascino Signed-off-by: Andrei Vagin --- arch/arm64/kernel/vdso.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index f3baecd8edfb..8b17d7d10729 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -235,6 +235,17 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, return vmf_insert_pfn(vma, vmf->address, pfn); } +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; + + if (new_size != VVAR_NR_PAGES * PAGE_SIZE) + return -EINVAL; + + return 0; +} + static int __setup_additional_pages(enum arch_vdso_type arch_index, struct mm_struct *mm, struct linux_binprm *bprm, @@ -317,6 +328,7 @@ static struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = { { .name = "[vvar]", .fault = vvar_fault, + .mremap = vvar_mremap, }, { .name = "[vdso]", @@ -488,6 +500,7 @@ static struct vm_special_mapping vdso_spec[A_PAGES] __ro_after_init = { { .name = "[vvar]", .fault = vvar_fault, + .mremap = vvar_mremap, }, { .name = "[vdso]", -- 2.24.1