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,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 50930C2D0EF for ; Thu, 16 Apr 2020 05:27:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C69D2076A for ; Thu, 16 Apr 2020 05:27:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sWvjSCgN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406722AbgDPF13 (ORCPT ); Thu, 16 Apr 2020 01:27:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37032 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2406511AbgDPF0s (ORCPT ); Thu, 16 Apr 2020 01:26:48 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70C12C061A10 for ; Wed, 15 Apr 2020 22:26:48 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id t40so878747pjb.3 for ; Wed, 15 Apr 2020 22:26:48 -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=AEQhnnrMzAKTzUbyWrr7Pn4129iWSFF1XGDPYTPl2Oo=; b=sWvjSCgNi/pGxJ8po/5HgKguAxlQRy+wCBCGw8arJtEyunm27lNPBjARK9WhHOxtuN PCDJQbLfnmWLVk1MnPOlWVYUs97/Wy2E8cJHx8x/J01Ub27iy/U2s/wFJUeZQRgmeG6v nv6a2yjc5r19eVoqvfywnonahteeHbS/nJzY6SiJKvzAhSQXJxZaHeUUHOzp4rvfXg3o PhvP8YF87YuawnruPOYOd55HhIJc6LsLXSgAe3BY+WNbTr2TY+NJAmMfjbXZj3G8Fn3G u8lJSQ928A4dYFDNmfcwgxQJf16qA6B0PT+kT6jmI2cbwspu1P46Q26TJ6FqsuI8L+cW HfbA== 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=AEQhnnrMzAKTzUbyWrr7Pn4129iWSFF1XGDPYTPl2Oo=; b=O/lwWuH9mH3S04OiSfua2sD1NRTJTpoobvTzWAt0+NBYRPJEsS6gCm++lVPluxnryC FJfKA997Z1FbCPfgWb3VHG1QI/DRFmN8zy2ofhNiDf5zZzoIfrf9o2a8dyH0aVkUr79B 0+/VK/MuRIGNX3Kn5iunNRe5H+4n/If3z0qzgJno7C2i+EPe0vTXv1SffyfvJ/sK/T9f U+4Uk4mHS0y/ynP84NkWW3G4It1KXqgJMqoRKs51cFN6ex4MANnH8w2DtKGFcsew69s0 gPLQLUquNmn+TZ5Yaf6mZGVzm26dbFdvnikHaAmZQL1j0cal9Epg0fBiXnjENd5ewwYK zkKg== X-Gm-Message-State: AGi0PuYQJuK3tBa7fJEA96vl99PWUQyYwkiW0SjXuDjW1MDvraeGyEOX nFu7T08YvL8Lh20Fg2BSjHI= X-Google-Smtp-Source: APiQypIgTAWtfPtyJjPPgrd+7oA27QM8CD3i2vxGeg9P6ikV7cBNyesXqbfzDxy45o2NIKtFDcNuEQ== X-Received: by 2002:a17:90a:a402:: with SMTP id y2mr3199895pjp.55.1587014807867; Wed, 15 Apr 2020 22:26:47 -0700 (PDT) Received: from laptop.hsd1.wa.comcast.net ([2601:600:817f:a132:df3e:521d:99d5:710d]) by smtp.gmail.com with ESMTPSA id c21sm53699pjr.2.2020.04.15.22.26.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2020 22:26:47 -0700 (PDT) From: Andrei Vagin To: Vincenzo Frascino , Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Rutland , Thomas Gleixner , Andrei Vagin , Dmitry Safonov Subject: [PATCH 5/6] arm64/vdso: Restrict splitting VVAR VMA Date: Wed, 15 Apr 2020 22:26:17 -0700 Message-Id: <20200416052618.804515-6-avagin@gmail.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200416052618.804515-1-avagin@gmail.com> References: <20200416052618.804515-1-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 fb32c6f76078..c003f7ee383a 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, @@ -315,6 +326,7 @@ static struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = { { .name = "[vvar]", .fault = vvar_fault, + .mremap = vvar_mremap, }, { .name = "[vdso]", @@ -497,6 +509,7 @@ 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