dt: introduce for_each_available_child_of_node, of_get_next_available_child

Macro for_each_child_of_node() makes it easy to iterate over all of the
children for a given device tree node, including those nodes that are
marked as unavailable (i.e. status = "disabled").

Introduce for_each_available_child_of_node(), which is like
for_each_child_of_node(), but it automatically skips unavailable nodes.
This also requires the introduction of helper function
of_get_next_available_child(), which returns the next available child
node.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
arm: Allow remapping lowmem as 4K pages

Lowmem is currently mapped with sections (1MB/2MB) whenever
possible due to TLB performance boosts. Sections cannot easily
be changed at runtime however which makes implementing certain
features annoying. Add an option to map lowmem with 4K patches.
This is intended to be used as a debugging feature and should
NOT be used for performance testing.

Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
mm: Mark free pages as read only

Drivers have a tendency to scribble on everything, including free
pages. Make life easier by marking free pages as read only when
on the buddy list and re-marking as read/write when allocating.

Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
list: introduce list_first_entry_or_null

non-rcu variant of list_first_or_null_rcu

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Update Config.