On Wednesday, October 02, 2013 1:32 PM, Bird, Tim wrote:

A significant difficulty is that the kernel memory for ARM is currently mapped by
section (that is, using 1MB sections). This means that small memory areas
cannot be individually re-mapped RO on page boundaries. If the kernel has code
which must be writable for some reason, then with that current mapping, at least
a 1MB section would be used for that writable code.

FYI - Sony has patches to support 4KB mappings for the kernel, for ARM,
which they've been using internally. These might be useful
for this feature.