[ARM_LINUX] ioremap() allowing to map system memory...

[arlie@worldash.org (Arlie Stephens)]

On Mar 01 2013, Valdis.Kletnieks at vt.edu wrote:
> X-Mailer: exmh version 2.8.0 04/21/2012 with nmh-1.4-dev
> 
> On Fri, 01 Mar 2013 16:48:12 +0530, sandeep kumar said:
> 
> > Don't you think it should throw panic()while calling the ioremap() itself.
> > Because this sounds like a serious violation...
> 
> As you noted, it does give you a warning.
> 
> That's a kernel design philosophy - to reserve the panic() and BUG()
> calls for cases where it is *known* that proceeding further is
> unsafe or impossible.  So the kernel does a panic() if it can't start
> /sbin/init at system boot-up - because without that, further progress
> is impossible.  But once the system is up, we don't panic if PID 1 goes
> away - because it's possible that the user has an open window, and can su
> and at least do an orderly shutdown.

[snippage]

> So that's the design philosophy of why it gives you a warning rather than
> a panic.

Great explanation. Thank you. 

I figured it would be something vaguely like this, but I'm very new to
the *linux* kernel, so I wasn't going to try to answer. 

--
Arlie

(Arlie Stephens						arlie at worldash.org)