Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754354AbZGOM1O (ORCPT ); Wed, 15 Jul 2009 08:27:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754148AbZGOM1N (ORCPT ); Wed, 15 Jul 2009 08:27:13 -0400 Received: from mx2.redhat.com ([66.187.237.31]:54673 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753702AbZGOM1N (ORCPT ); Wed, 15 Jul 2009 08:27:13 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <8bd0f97a0907150455l59a86540l655604579ab70b4f@mail.gmail.com> References: <8bd0f97a0907150455l59a86540l655604579ab70b4f@mail.gmail.com> <1247591665-12000-1-git-send-email-vapier@gentoo.org> <20090714161416.GA19147@cmpxchg.org> <6206.1247592126@redhat.com> <4A5CFFD8.7020106@t-online.de> <12377.1247654255@redhat.com> <8bd0f97a0907150412h234cf4d6l439d92d832055373@mail.gmail.com> <2898.1247658300@redhat.com> To: Mike Frysinger Cc: dhowells@redhat.com, Bernd Schmidt , uclinux-dist-devel@blackfin.uclinux.org, linux-kernel@vger.kernel.org Subject: Re: [Uclinux-dist-devel] [PATCH v2] NOMMU: add support for Memory Protection Units (MPU) Date: Wed, 15 Jul 2009 13:25:42 +0100 Message-ID: <3751.1247660742@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 954 Lines: 23 Mike Frysinger wrote: > yes, you can see page_rwx_mask in our mmu.h's mm_context_t. this is > what the protect_page/update_protections operate on. we have a global > current_rwx_mask that gets updated during context changes and the CPLB > miss handler uses that to keep things simple. Interesting. Since FRV does not really allow separate execute permissions (it has a very few separate static I and D protection/mapping registers and a shared TLB), I could do it with just pairs of bits. Also, how do you deal with mappable devices that lie outside of RAM? I'm guessing from the code that you don't cover those with the bitmap, but rather just grant userspace RW access. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/