[PATCH] Provide a stub ioperm implementation for ARMv5 and later

[Phil Blundell]

On Sat, 2015-12-12 at 19:59 +0100, Aurelien Jarno wrote:
> The ioperm, iopl, in{b,w,l} and out{b,w,l} functions only make sense
> on ARMv4.

This statement isn't strictly true.  There is no inherent relationship
between the architecture level and the availability or not of the
port-mapped I/O functions.  And, in fact, a quick survey suggests that
there is at least one counterexample in the kernel: CONFIG_ARCH_VIPER is
a PXA25x board (hence ARMv5TE) and seems to include ISA.  So, I am not
all that keen on this patch. 

If you wanted to clean up the ioperm code a bit then it would probably
make sense to remove all the legacy stuff that grubs around
in /proc/cpuinfo and /etc/arm_systype to figure out what sort of machine
it's on, since this is only needed for kernels that are so old as to
lack the CTL_BUS_ISA sysctls.

p.