1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _TIMEKEEPING_INTERNAL_H
3 #define _TIMEKEEPING_INTERNAL_H
4 
5 #include <linux/clocksource.h>
6 #include <linux/spinlock.h>
7 #include <linux/time.h>
8 
9 /*
10  * timekeeping debug functions
11  */
12 #ifdef CONFIG_DEBUG_FS
13 extern void tk_debug_account_sleep_time(const struct timespec64 *t);
14 #else
15 #define tk_debug_account_sleep_time(x)
16 #endif
17 
18 #ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
clocksource_delta(u64 now,u64 last,u64 mask)19 static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
20 {
21 	u64 ret = (now - last) & mask;
22 
23 	/*
24 	 * Prevent time going backwards by checking the MSB of mask in
25 	 * the result. If set, return 0.
26 	 */
27 	return ret & ~(mask >> 1) ? 0 : ret;
28 }
29 #else
clocksource_delta(u64 now,u64 last,u64 mask)30 static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
31 {
32 	return (now - last) & mask;
33 }
34 #endif
35 
36 /* Semi public for serialization of non timekeeper VDSO updates. */
37 extern raw_spinlock_t timekeeper_lock;
38 
39 #endif /* _TIMEKEEPING_INTERNAL_H */
40