If PG_dcache_dirty is set for a page, we need to flush the source page
before performing any copypage operation using a different virtual address.

This fixes the copypage implementations for XScale, StrongARM and ARMv6.

This patch fixes segmentation faults seen in the dynamic linker under
the usage patterns in glibc 2.4/2.5.
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

L_PTE_ASID is not really required to be stored in every PTE, since we
can identify it via the address passed to set_pte_at().  So, create
set_pte_ext() which takes the address of the PTE to set, the Linux
PTE value, and the additional CPU PTE bits which aren't encoded in
the Linux PTE value.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move top_pmd into arch/arm/mm/mm.h - nothing outside arch/arm/mm
references it.

Move the repeated definition of TOP_PTE into mm/mm.h, as well as
a few function prototypes.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The ARM copypage changes in 2.6.12-rc4-git1 removed the preempt locking
from the copypage functions which broke the XScale implementation.
This patch fixes the locking on XScale and removes the now unneeded
minicache code.
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>
Checked-by: Richard Purdie