powerpc: Implement CONFIG_STRICT_DEVMEM
As described in the help text in the patch, this token restricts general
access to /dev/mem as a way of increasing the security. Specifically, access
to exclusive IOMEM and kernel RAM is denied unless CONFIG_STRICT_DEVMEM is
set to 'n'.
Implement the 'devmem_is_allowed()' interface for Powerpc. It will be
called from range_is_allowed() when userpsace attempts to access /dev/mem.
This patch is based on an earlier patch from Steve Best and with input from
Paul Mackerras and Scott Wood.
[BenH] Fixed a typo or two and removed the generic change which should
be submitted as a separate patch
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
3 files changed