ANDROID: timer: Add vendor hook for timer calc index

Since we're expecting timers more precisely in short period, add
a vendor hook to calc_index when adding timers. Then we can modify
the index this timer used to make it accurate.

Bug: 178758017
Signed-off-by: Huang Yiwei <hyiwei@codeaurora.org>
Change-Id: Ie0e6493ae7ad53b0cc57eb1bbcf8a0a11f652828

kernel/time/timer.c

@@ -55,6 +55,8 @@
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/timer.h>
+#undef CREATE_TRACE_POINTS
+#include <trace/hooks/timer.h>
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(hrtimer_expire_entry);
 EXPORT_TRACEPOINT_SYMBOL_GPL(hrtimer_expire_exit);
@@ -505,6 +507,7 @@ static inline unsigned calc_index(unsigned long expires, unsigned lvl,
 	 * Round up with level granularity to prevent this.
 	 */
 	expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl);
+	trace_android_vh_timer_calc_index(lvl, &expires);
 	*bucket_expiry = expires << LVL_SHIFT(lvl);
 	return LVL_OFFS(lvl) + (expires & LVL_MASK);
 }