From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Chapman Date: Sat, 18 Oct 2003 02:01:52 +0000 Subject: Re: [RFC] prevent "dd if=/dev/mem" crash Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Fri, Oct 17, 2003 at 06:48:33PM -0700, David Mosberger wrote: > >>>>> On Fri, 17 Oct 2003 17:49:55 -0700, Andrew Morton said: > > Andrew> We _want_ to be able to read mmio ranges via /dev/mem, don't > Andrew> we? I guess it has never come up because everyone uses > Andrew> kmem. > > I just don't see how making a "dd if=/dev/mem" safe and allowing > access to arbitrary physical memory can go to together. Given that > /dev/mem _is_ being used for accessing mmio space, is it really worth > bothering trying to make such a "dd" safe? Usually people who want to access MMIO devices would use mmap rather than read/write. But I do agree that the current semantics are not unreasonable and the user should think about what they're doing before accessing random parts of /dev/mem. Matt