From: Ingo Molnar <mingo@elte.hu>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary
Date: Mon, 20 Jun 2011 16:40:45 +0000 [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 16:40 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-17 8:38 [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses 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 9:30 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Ingo Molnar
2011-06-17 9:41 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of Russell King - ARM Linux
2011-06-17 9:55 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Petr Tesarik
2011-06-20 2:42 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Américo Wang
2011-06-27 7:46 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of Petr Tesarik
2011-06-19 23:02 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary 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 6:56 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of Srivatsa Vaddagiri
2011-06-20 0:42 ` Matthew Wilcox
2011-06-20 0:46 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Ryan Mallon
2011-06-20 0:52 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of Matthew Wilcox
2011-06-20 1:02 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary 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 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Petr Tesarik
2011-07-01 12:58 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Ingo Molnar
2011-07-01 13:43 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Petr Tesarik
2011-07-01 13:47 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary 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 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Petr Tesarik
2011-07-01 15:36 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Ingo Molnar
2011-07-01 16:00 ` H. Peter Anvin
2011-07-01 16:13 ` Ingo Molnar
2011-07-01 19:34 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Petr Tesarik
2011-07-01 19:56 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Ingo Molnar
2011-07-01 20:44 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses Petr Tesarik
2011-07-03 19:46 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary Ingo Molnar
2011-07-05 17:49 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of Matthew Garrett
2011-07-05 17:56 ` [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary H. Peter Anvin
2011-07-05 22:34 ` H. Peter Anvin
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