K 10 svn:author V 3 ian K 8 svn:date V 27 2014-03-09T15:36:56.166986Z K 7 svn:log V 603 Make undefined exception entry MPSAFE. The old code used static storage to preserve a couple registers while setting up the trapframe for the main handler. Doing so was the last leftover crumbs from the days when a low-level debugger was hooked into the exception entry code. Now the exception entry sequence is essentially the same as for the other exceptions, which still involves needlessly indirecting through a function pointer which points to the same code on every platform. Removing that indirection will be handled as a separate cleanup. This work is based on an analysis by Juergen Weiss. END