Use the base address of the lmb to derive the starting page frame number
instead of trying to extract it from the drc index of the lmb.  The drc
index should not be used for this as it will, and did, break.

Until this point, systems that have had memory represented in the device
tree with a node for each lmb the drc index would (luckily) closely
track the base address of the lmb.  For example a lmb with a drc index
of 8000000a would have a base address of a0000000.  This correlation
allowed the current code to derive the starting page frame number from
the drc inddex

Device tree layouts where lmbs are represented under the
ibm,dynamic-reconfiguration-memory node in the ibm,dynamic-memory
property do not have this correlation between the drc index and base
address of the lmb.
Signed-off-by: NNathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The powerpc kernel maintains information about logical memory blocks
in the lmb.memory structure, which is initialized and updated at boot
time, but not when memory is added or removed while the kernel is
running.

This adds a hotplug memory notifier which updates lmb.memory when
memory is added or removed.  This information is useful for eHEA
driver to find out the memory layout and holes.

NOTE: No special locking is needed for lmb_add() and lmb_remove().
Calls to these are serialized by caller. (pSeries_reconfig_chain).
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Hotplug memory remove notifier for 64-bit powerpc.  This gets invoked
by writing to /proc/ppc64/ofdt the string "remove_node " followed by
the firmware device tree pathname of the node that needs to be removed.

In response, this adjusts the sections and removes sysfs entries by
calling __remove_pages().  Then it calls arch-specific code to get rid
of the hardware MMU mappings for the section of memory.
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Reviewed-by: NMichael Ellerman <michael@ellerman.id.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>