K 10 svn:author V 3 jhb K 8 svn:date V 27 2016-12-23T03:07:19.304833Z K 7 svn:log V 593 MFC 309148: Permit timed sleeps for threads other than thread0 before timers are working. The callout subsystem already handles early callouts and schedules the first clock interrupt appropriately based on the currently pending callouts. The one nit to fix was that callouts scheduled via C_HARDCLOCK during early boot could fire too early once timers were enabled as the per-CPU base time is always zero until timers are initialized. The change in callout_when() handles this case by using the current uptime as the base time of the callout during bootup if the per-CPU base time is zero. END