Thanks to Tom Callaway for the excellent bug report and
test case.

sys_ipc() has several problems, most to due with semaphore
call handling:

1) 'err' return should be a 'long'
2) "union semun" is passed in a register on 64-bit compared
   to 32-bit which provides it on the stack and therefore
   by reference
3) Second and third arguments to SEMCTL are swapped compared
   to 32-bit.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@kernel.org>