projects/linux·blob v6.1 · refs

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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_TIME64_H
3#define _LINUX_TIME64_H
4
5#include <linux/math64.h>
6#include <vdso/time64.h>
7
8typedef __s64 time64_t;
9typedef __u64 timeu64_t;
10
11#include <uapi/linux/time.h>
12
13struct timespec64 {
14 time64_t tv_sec; /* seconds */
15 long tv_nsec; /* nanoseconds */
16};
17
18struct itimerspec64 {
19 struct timespec64 it_interval;
20 struct timespec64 it_value;
21};
22
23/* Parameters used to convert the timespec values: */
24#define PSEC_PER_NSEC 1000L
25
26/* Located here for timespec[64]_valid_strict */
27#define TIME64_MAX ((s64)~((u64)1 << 63))
28#define TIME64_MIN (-TIME64_MAX - 1)
29
30#define KTIME_MAX ((s64)~((u64)1 << 63))
31#define KTIME_MIN (-KTIME_MAX - 1)
32#define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC)
33#define KTIME_SEC_MIN (KTIME_MIN / NSEC_PER_SEC)
34
35/*
36 * Limits for settimeofday():
37 *
38 * To prevent setting the time close to the wraparound point time setting
39 * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
40 * should be really sufficient, which means the cutoff is 2232. At that
41 * point the cutoff is just a small part of the larger problem.
42 */
43#define TIME_UPTIME_SEC_MAX (30LL * 365 * 24 *3600)
44#define TIME_SETTOD_SEC_MAX (KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
45
46static inline int timespec64_equal(const struct timespec64 *a,
47 const struct timespec64 *b)
48{
49 return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
50}
51
52/*
53 * lhs < rhs: return <0
54 * lhs == rhs: return 0
55 * lhs > rhs: return >0
56 */
57static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
58{
59 if (lhs->tv_sec < rhs->tv_sec)
60 return -1;
61 if (lhs->tv_sec > rhs->tv_sec)
62 return 1;
63 return lhs->tv_nsec - rhs->tv_nsec;
64}
65
66extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
67
68static inline struct timespec64 timespec64_add(struct timespec64 lhs,
69 struct timespec64 rhs)
70{
71 struct timespec64 ts_delta;
72 set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
73 lhs.tv_nsec + rhs.tv_nsec);
74 return ts_delta;
75}
76
77/*
78 * sub = lhs - rhs, in normalized form
79 */
80static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
81 struct timespec64 rhs)
82{
83 struct timespec64 ts_delta;
84 set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
85 lhs.tv_nsec - rhs.tv_nsec);
86 return ts_delta;
87}
88
89/*
90 * Returns true if the timespec64 is norm, false if denorm:
91 */
92static inline bool timespec64_valid(const struct timespec64 *ts)
93{
94 /* Dates before 1970 are bogus */
95 if (ts->tv_sec < 0)
96 return false;
97 /* Can't have more nanoseconds then a second */
98 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
99 return false;
100 return true;
101}
102
103static inline bool timespec64_valid_strict(const struct timespec64 *ts)
104{
105 if (!timespec64_valid(ts))
106 return false;
107 /* Disallow values that could overflow ktime_t */
108 if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
109 return false;
110 return true;
111}
112
113static inline bool timespec64_valid_settod(const struct timespec64 *ts)
114{
115 if (!timespec64_valid(ts))
116 return false;
117 /* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
118 if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
119 return false;
120 return true;
121}
122
123/**
124 * timespec64_to_ns - Convert timespec64 to nanoseconds
125 * @ts: pointer to the timespec64 variable to be converted
126 *
127 * Returns the scalar nanosecond representation of the timespec64
128 * parameter.
129 */
130static inline s64 timespec64_to_ns(const struct timespec64 *ts)
131{
132 /* Prevent multiplication overflow / underflow */
133 if (ts->tv_sec >= KTIME_SEC_MAX)
134 return KTIME_MAX;
135
136 if (ts->tv_sec <= KTIME_SEC_MIN)
137 return KTIME_MIN;
138
139 return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
140}
141
142/**
143 * ns_to_timespec64 - Convert nanoseconds to timespec64
144 * @nsec: the nanoseconds value to be converted
145 *
146 * Returns the timespec64 representation of the nsec parameter.
147 */
148extern struct timespec64 ns_to_timespec64(s64 nsec);
149
150/**
151 * timespec64_add_ns - Adds nanoseconds to a timespec64
152 * @a: pointer to timespec64 to be incremented
153 * @ns: unsigned nanoseconds value to be added
154 *
155 * This must always be inlined because its used from the x86-64 vdso,
156 * which cannot call other kernel functions.
157 */
158static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
159{
160 a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
161 a->tv_nsec = ns;
162}
163
164/*
165 * timespec64_add_safe assumes both values are positive and checks for
166 * overflow. It will return TIME64_MAX in case of overflow.
167 */
168extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
169 const struct timespec64 rhs);
170
171#endif /* _LINUX_TIME64_H */