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  
8  typedef __s64 time64_t;
9  typedef __u64 timeu64_t;
10  
11  #include <uapi/linux/time.h>
12  
13  struct timespec64 {
14  	time64_t	tv_sec;			/* seconds */
15  	long		tv_nsec;		/* nanoseconds */
16  };
17  
18  struct 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  
timespec64_equal(const struct timespec64 * a,const struct timespec64 * b)46  static 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   */
timespec64_compare(const struct timespec64 * lhs,const struct timespec64 * rhs)57  static 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  
66  extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
67  
timespec64_add(struct timespec64 lhs,struct timespec64 rhs)68  static 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   */
timespec64_sub(struct timespec64 lhs,struct timespec64 rhs)80  static 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   */
timespec64_valid(const struct timespec64 * ts)92  static 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  
timespec64_valid_strict(const struct timespec64 * ts)103  static 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  
timespec64_valid_settod(const struct timespec64 * ts)113  static 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   */
timespec64_to_ns(const struct timespec64 * ts)130  static 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   */
148  extern 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   */
timespec64_add_ns(struct timespec64 * a,u64 ns)158  static __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   */
168  extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
169  					 const struct timespec64 rhs);
170  
171  #endif /* _LINUX_TIME64_H */
172