of arbitrary user pages (f.e. for ptrace()) it will use
these two routines.
- The page has been kmap()'d, and flush_cache_page() has
- just been called for the user mapping of this page (if
- necessary).
-
Any necessary cache flushing or other coherency operations
that need to occur should happen here. If the processor's
instruction cache does not snoop cpu stores, it is very