This adds a set of test cases to test the behaviour of
copy_tofrom_user when exceptions are encountered accessing the
source or destination. Currently, copy_tofrom_user does not always
copy as many bytes as possible when an exception occurs on a store
to the destination, and that is reflected in failures in these tests.
Based on a test program from Anton Blanchard.
[firstname.lastname@example.org - test all three paths, wrote commit description,
made EX_TABLE create an exception table.]
Signed-off-by: Paul Mackerras <email@example.com>
Signed-off-by: Michael Ellerman <firstname.lastname@example.org>