Re: [RFC] prevent "dd if=/dev/mem" crash

[Matt Chapman]

On Fri, Oct 17, 2003 at 06:48:33PM -0700, David Mosberger wrote:
> >>>>> On Fri, 17 Oct 2003 17:49:55 -0700, Andrew Morton <akpm@xxxxxxxx> 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

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