bitkeeper revision 1.1159.187.21 (41a85113PA1gYVqMumQ4r2S3y6POGw)

bitkeeper revision 1.1159.187.21 (41a85113PA1gYVqMumQ4r2S3y6POGw)

Clean up and fix the 2.6 entry.S:
 1. Save and restore the event_mask in SAVE_ALL / restore_all.
 2. No need to keep reloading %esi all oevr the place as we can load it
    once on entry (e.g., SAVE_ALL) and thereafter it is callee-saves.
 3. No need for extra XEN_UNBLOCK_EVENTS() where native isn't doing a 'sti',
    even if the code looks broken -- it is okay to call schedule() with
    interrupts off, in which case it will reenable them itself.
 4. Fixed another KERNEL_DS -> USER_DS.
 5. Unmacroed the page fault handler.
 6. A bunch of other tiny fixes....