From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 879F06B008A for ; Tue, 4 Jan 2011 11:25:43 -0500 (EST) From: Johan MOSSBERG Date: Tue, 4 Jan 2011 17:23:37 +0100 Subject: RE: [PATCHv8 00/12] Contiguous Memory Allocator Message-ID: References: <20101223100642.GD3636@n2100.arm.linux.org.uk> In-Reply-To: <20101223100642.GD3636@n2100.arm.linux.org.uk> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org To: Russell King - ARM Linux , Kyungmin Park Cc: Michal Nazarewicz , "linux-arm-kernel@lists.infradead.org" , Daniel Walker , Mel Gorman , "linux-kernel@vger.kernel.org" , Michal Nazarewicz , "linux-mm@kvack.org" , Ankita Garg , Andrew Morton , "linux-media@vger.kernel.org" , KAMEZAWA Hiroyuki , Marek Szyprowski List-ID: Russell King wrote: > Has anyone addressed my issue with it that this is wide-open for > abuse by allocating large chunks of memory, and then remapping > them in some way with different attributes, thereby violating the > ARM architecture specification? I seem to have missed the previous discussion about this issue. Where in the specification (preferably ARMv7) can I find information about this? Is the problem that it is simply forbidden to map an address multiple times with different cache setting and if this is done the hardware might start failing? Or is the problem that having an address mapped cached means that speculative pre-fetch can read it into the cache at any time, possibly causing problems if an un-cached mapping exists? In my opinion option number two can be handled and I've made an attempt at doing that in hwmem (posted on linux-mm a while ago), look in cache_handler.c. Hwmem currently does not use cma but the next version probably will. /Johan Mossberg -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org