From: Ingo Molnar <mingo@elte.hu>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ryan Mallon <rmallon@gmail.com>, Petr Tesarik <ptesarik@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@redhat.com>,
Paul Mundt <lethal@linux-sh.org>,
Russell King <linux@arm.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Tony Luck <tony.luck@intel.com>,
x86@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
linux-kernel@vger.kernel.org,
Arjan van de Ven <arjan@infradead.org>,
Dave Jones <davej@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses
Date: Mon, 20 Jun 2011 18:40:45 +0200 [thread overview]
Message-ID: <20110620164045.GB10815@elte.hu> (raw)
In-Reply-To: <4DFF6E58.8090306@zytor.com>
* H. Peter Anvin <hpa@zytor.com> wrote:
> On 06/20/2011 12:41 AM, Ingo Molnar wrote:
> >
> > * H. Peter Anvin <hpa@zytor.com> wrote:
> >
> >> There are some test drivers which really want /dev/mem to work.
> >
> > Test drivers and test hardware with zero enumeration can use below 4G
> > addresses just fine.
> >
> > Also, debugging is not an issue and some non-default kernel or boot
> > option can enable any sort of device i guess, so my main worry isnt
> > really security but that we should stand in the way of the apparent
> > practice of *shipping* user-space drivers that use /dev/mem ...
> >
>
> We should either fix /dev/mem to work according to its
> specification or rip it out. The issue with test drivers is not
> spurious... I ran into this one myself a few weeks ago while trying
> to do a memory test (by limiting the amount of memory available to
> the kernel). This is something that is typically done on factory
> floors, and it would be nice to be able to get those environments
> over to using Linux.
There is no reason why they couldnt use a .config option or a boot
option to get their weird stuff going, which weird stuff also happens
to be useful.
What i'm somewhat against is having this enabled by default for weird
stuff that also happens to be harmful - and the fact that it never
worked over 4G physical gives us the perfect opportunity to do just
that.
Thanks,
Ingo
next prev parent reply other threads:[~2011-06-20 16:41 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-17 8:38 Petr Tesarik
2011-06-17 8:43 ` [PATCH 01/10] Return EOF on out-of-bounds read from /dev/mem Petr Tesarik
2011-06-17 8:44 ` [PATCH 02/10] (un)xlate_dev_mem_ptr: use phys_addr_t for the @phys parameter Petr Tesarik
2011-06-17 8:45 ` [PATCH 03/10] x86: translate highmem /dev/mem pointers Petr Tesarik
2011-06-17 8:45 ` [PATCH 04/10] ia64: change xlate_dev_mem_ptr's argument to phys_addr_t Petr Tesarik
2011-06-17 8:45 ` [PATCH 05/10] valid_phys_addr_range: use phys_addr_t for the @addr parameter Petr Tesarik
2011-06-17 8:46 ` [PATCH 06/10] sh: change valid_phys_addr_range's @addr param to phys_addr_t Petr Tesarik
2011-06-17 8:46 ` [PATCH 07/10] arm: " Petr Tesarik
2011-06-17 8:47 ` [PATCH 08/10] ia64: " Petr Tesarik
2011-06-17 8:48 ` [PATCH 09/10] x86: provide arch-specific valid_phys_addr_range() Petr Tesarik
2011-06-17 8:48 ` [PATCH 10/10] Allow reading/writing all memory through /dev/mem Petr Tesarik
2011-06-17 9:30 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Ingo Molnar
2011-06-17 9:41 ` Russell King - ARM Linux
2011-06-17 9:55 ` Petr Tesarik
2011-06-20 2:42 ` Américo Wang
2011-06-27 7:46 ` Petr Tesarik
2011-06-19 23:02 ` Ryan Mallon
2011-06-19 23:44 ` H. Peter Anvin
2011-06-20 7:41 ` Ingo Molnar
2011-06-20 15:59 ` H. Peter Anvin
2011-06-20 16:40 ` Ingo Molnar [this message]
2011-06-20 16:44 ` H. Peter Anvin
2011-06-21 6:55 ` Srivatsa Vaddagiri
2011-06-20 0:42 ` Matthew Wilcox
2011-06-20 0:46 ` Ryan Mallon
2011-06-20 0:52 ` Matthew Wilcox
2011-06-20 1:02 ` Ryan Mallon
2011-06-20 7:31 ` Ingo Molnar
2011-06-20 8:03 ` Ryan Mallon
2011-06-20 17:10 ` Ray Lee
2011-06-29 9:05 ` Petr Tesarik
2011-07-01 12:58 ` Ingo Molnar
2011-07-01 13:43 ` Petr Tesarik
2011-07-01 13:47 ` Christoph Hellwig
2011-07-01 14:37 ` Ingo Molnar
2011-07-01 14:41 ` Christoph Hellwig
2011-07-01 14:46 ` Ingo Molnar
2011-07-01 14:54 ` Petr Tesarik
2011-07-01 15:36 ` Ingo Molnar
2011-07-01 16:00 ` H. Peter Anvin
2011-07-01 16:13 ` Ingo Molnar
2011-07-01 19:34 ` Petr Tesarik
2011-07-01 19:56 ` Ingo Molnar
2011-07-01 20:44 ` Petr Tesarik
2011-07-03 19:46 ` Ingo Molnar
2011-07-05 17:49 ` Matthew Garrett
2011-07-05 17:56 ` H. Peter Anvin
2011-07-05 22:34 ` H. Peter Anvin
2011-06-20 13:24 Dave Anderson
2011-06-21 2:52 ` Cong Wang
2011-06-21 13:03 ` Dave Anderson
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