xref: /linux-6.15/include/linux/time64.h (revision e00a844a)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_TIME64_H
3 #define _LINUX_TIME64_H
4 
5 #include <uapi/linux/time.h>
6 #include <linux/math64.h>
7 
8 typedef __s64 time64_t;
9 typedef __u64 timeu64_t;
10 
11 #if __BITS_PER_LONG == 64
12 /* this trick allows us to optimize out timespec64_to_timespec */
13 # define timespec64 timespec
14 #define itimerspec64 itimerspec
15 #else
16 struct timespec64 {
17 	time64_t	tv_sec;			/* seconds */
18 	long		tv_nsec;		/* nanoseconds */
19 };
20 
21 struct itimerspec64 {
22 	struct timespec64 it_interval;
23 	struct timespec64 it_value;
24 };
25 
26 #endif
27 
28 /* Parameters used to convert the timespec values: */
29 #define MSEC_PER_SEC	1000L
30 #define USEC_PER_MSEC	1000L
31 #define NSEC_PER_USEC	1000L
32 #define NSEC_PER_MSEC	1000000L
33 #define USEC_PER_SEC	1000000L
34 #define NSEC_PER_SEC	1000000000L
35 #define FSEC_PER_SEC	1000000000000000LL
36 
37 /* Located here for timespec[64]_valid_strict */
38 #define TIME64_MAX			((s64)~((u64)1 << 63))
39 #define KTIME_MAX			((s64)~((u64)1 << 63))
40 #define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
41 
42 static inline int timespec64_equal(const struct timespec64 *a,
43 				   const struct timespec64 *b)
44 {
45 	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
46 }
47 
48 /*
49  * lhs < rhs:  return <0
50  * lhs == rhs: return 0
51  * lhs > rhs:  return >0
52  */
53 static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
54 {
55 	if (lhs->tv_sec < rhs->tv_sec)
56 		return -1;
57 	if (lhs->tv_sec > rhs->tv_sec)
58 		return 1;
59 	return lhs->tv_nsec - rhs->tv_nsec;
60 }
61 
62 extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
63 
64 static inline struct timespec64 timespec64_add(struct timespec64 lhs,
65 						struct timespec64 rhs)
66 {
67 	struct timespec64 ts_delta;
68 	set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
69 				lhs.tv_nsec + rhs.tv_nsec);
70 	return ts_delta;
71 }
72 
73 /*
74  * sub = lhs - rhs, in normalized form
75  */
76 static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
77 						struct timespec64 rhs)
78 {
79 	struct timespec64 ts_delta;
80 	set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
81 				lhs.tv_nsec - rhs.tv_nsec);
82 	return ts_delta;
83 }
84 
85 /*
86  * Returns true if the timespec64 is norm, false if denorm:
87  */
88 static inline bool timespec64_valid(const struct timespec64 *ts)
89 {
90 	/* Dates before 1970 are bogus */
91 	if (ts->tv_sec < 0)
92 		return false;
93 	/* Can't have more nanoseconds then a second */
94 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
95 		return false;
96 	return true;
97 }
98 
99 static inline bool timespec64_valid_strict(const struct timespec64 *ts)
100 {
101 	if (!timespec64_valid(ts))
102 		return false;
103 	/* Disallow values that could overflow ktime_t */
104 	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
105 		return false;
106 	return true;
107 }
108 
109 /**
110  * timespec64_to_ns - Convert timespec64 to nanoseconds
111  * @ts:		pointer to the timespec64 variable to be converted
112  *
113  * Returns the scalar nanosecond representation of the timespec64
114  * parameter.
115  */
116 static inline s64 timespec64_to_ns(const struct timespec64 *ts)
117 {
118 	return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
119 }
120 
121 /**
122  * ns_to_timespec64 - Convert nanoseconds to timespec64
123  * @nsec:	the nanoseconds value to be converted
124  *
125  * Returns the timespec64 representation of the nsec parameter.
126  */
127 extern struct timespec64 ns_to_timespec64(const s64 nsec);
128 
129 /**
130  * timespec64_add_ns - Adds nanoseconds to a timespec64
131  * @a:		pointer to timespec64 to be incremented
132  * @ns:		unsigned nanoseconds value to be added
133  *
134  * This must always be inlined because its used from the x86-64 vdso,
135  * which cannot call other kernel functions.
136  */
137 static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
138 {
139 	a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
140 	a->tv_nsec = ns;
141 }
142 
143 /*
144  * timespec64_add_safe assumes both values are positive and checks for
145  * overflow. It will return TIME64_MAX in case of overflow.
146  */
147 extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
148 					 const struct timespec64 rhs);
149 
150 #endif /* _LINUX_TIME64_H */
151