From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755742AbcJXKXH (ORCPT ); Mon, 24 Oct 2016 06:23:07 -0400 Received: from shell.dhp.com ([199.4.150.5]:2198 "EHLO shell.dhp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbcJXKXE (ORCPT ); Mon, 24 Oct 2016 06:23:04 -0400 Date: Mon, 24 Oct 2016 10:23:03 +0000 (/etc/localtime) From: To: linux-kernel@vger.kernel.org Subject: Re: /dev/mem arch/x86 mm/pat.c break In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey, It looks like https://lkml.org/lkml/2016/7/8/160 may have taken care of it.. though back in, March or so, I saw it in some recent kernels and had to make this patch myself.. so I dont know if it's committed. --n On Mon, 24 Oct 2016 n@dhp.com wrote: > Hi, > > Unless I read C wrong, pat.c seems to break all non-strict devmem use. I > discovered this while reversing a bunch of pci and other low-level > stuff. Here is a link to the fix, http//users.dhp.com/~n/pubs/ > the one starting with Linux-86...txt is the correct file, those kernel > bugs in OpenBSD and that are just hilarious enough to keep around.. > > Oh, here is the full link: > http://users.dhp.com/~n/Linux-x86-mmap-nonstrict-broken.txt > > This was first 'nonpromisc_devmem', probably dating back to that > introduction of 1MB limits on mmap(2) way back in the day.. who knows. > > Alright, I confess as a kernel programmer Linux isn't my thing, I prefer > Unix particularly BSD and SysV (SVR4 would be sort of both). Thats mostly > because sys_call_table is sysent to me, as are tons of other symbols. But > still, /usr/libexec/cpp seems to have broken /dev/mem > mmap(2) functionality over the non-strict range of memory for.. a long > time. > > If I'm wrong, then there is no problem, however I had to fix this to get > things working. Thanks, I realize that #ifdef instead of #ifndef can > cause strictness reversals.. good thing other portions of the kernel had > this correct, or strict would be nonstrict, and vice-versa. Alright, > enjoy.. > > Reply address: n@mod.net (please). > > > > -n > > > > > >