From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756665AbcBXQTt (ORCPT ); Wed, 24 Feb 2016 11:19:49 -0500 Received: from foss.arm.com ([217.140.101.70]:45138 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750779AbcBXQTs (ORCPT ); Wed, 24 Feb 2016 11:19:48 -0500 Date: Wed, 24 Feb 2016 16:19:44 +0000 From: Catalin Marinas To: miles.chen@mediatek.com Cc: Will Deacon , srv_wsdupstream@mediatek.com, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] arm64/mm: fix virtual address boundary check Message-ID: <20160224161944.GJ4777@e104818-lin.cambridge.arm.com> References: <1456329708-2042-1-git-send-email-miles.chen@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1456329708-2042-1-git-send-email-miles.chen@mediatek.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 25, 2016 at 12:01:48AM +0800, miles.chen@mediatek.com wrote: > From: Miles Chen > > The MODULES_VADDR is not the lowest possible > kernel virtual address. TASK_SIZE_64 may be larger than > MODULES_VADDR, FIXADDR_TOP, and PCI_IO_START. > > Fix this by comparing TASK_SIZE_64 (highest user virtual address) > with VA_START (lowest kernel virtual address). > > #define VA_BITS (CONFIG_ARM64_VA_BITS) > #define VA_START (UL(0xffffffffffffffff) << VA_BITS) > #define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) > #define MODULES_END (PAGE_OFFSET) > #define MODULES_VADDR (MODULES_END - SZ_64M) > #define PCI_IO_END (MODULES_VADDR - SZ_2M) > #define PCI_IO_START (PCI_IO_END - PCI_IO_SIZE) > #define FIXADDR_TOP (PCI_IO_START - SZ_2M) > #define TASK_SIZE_64 (UL(1) << VA_BITS) We should remove these checks altogether. There is a huge gap between the user and kernel addresses that they would never overlap (we don't have enough levels of page tables to cover 64-bit VA space). -- Catalin