xref: /linux-6.15/include/linux/time.h (revision 6ed7ffdd)
1 #ifndef _LINUX_TIME_H
2 #define _LINUX_TIME_H
3 
4 # include <linux/cache.h>
5 # include <linux/seqlock.h>
6 # include <linux/math64.h>
7 #include <uapi/linux/time.h>
8 
9 extern struct timezone sys_tz;
10 
11 /* Parameters used to convert the timespec values: */
12 #define MSEC_PER_SEC	1000L
13 #define USEC_PER_MSEC	1000L
14 #define NSEC_PER_USEC	1000L
15 #define NSEC_PER_MSEC	1000000L
16 #define USEC_PER_SEC	1000000L
17 #define NSEC_PER_SEC	1000000000L
18 #define FSEC_PER_SEC	1000000000000000LL
19 
20 #define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
21 
22 static inline int timespec_equal(const struct timespec *a,
23                                  const struct timespec *b)
24 {
25 	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
26 }
27 
28 /*
29  * lhs < rhs:  return <0
30  * lhs == rhs: return 0
31  * lhs > rhs:  return >0
32  */
33 static inline int timespec_compare(const struct timespec *lhs, const struct timespec *rhs)
34 {
35 	if (lhs->tv_sec < rhs->tv_sec)
36 		return -1;
37 	if (lhs->tv_sec > rhs->tv_sec)
38 		return 1;
39 	return lhs->tv_nsec - rhs->tv_nsec;
40 }
41 
42 static inline int timeval_compare(const struct timeval *lhs, const struct timeval *rhs)
43 {
44 	if (lhs->tv_sec < rhs->tv_sec)
45 		return -1;
46 	if (lhs->tv_sec > rhs->tv_sec)
47 		return 1;
48 	return lhs->tv_usec - rhs->tv_usec;
49 }
50 
51 extern unsigned long mktime(const unsigned int year, const unsigned int mon,
52 			    const unsigned int day, const unsigned int hour,
53 			    const unsigned int min, const unsigned int sec);
54 
55 extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);
56 
57 /*
58  * timespec_add_safe assumes both values are positive and checks
59  * for overflow. It will return TIME_T_MAX if the reutrn would be
60  * smaller then either of the arguments.
61  */
62 extern struct timespec timespec_add_safe(const struct timespec lhs,
63 					 const struct timespec rhs);
64 
65 
66 static inline struct timespec timespec_add(struct timespec lhs,
67 						struct timespec rhs)
68 {
69 	struct timespec ts_delta;
70 	set_normalized_timespec(&ts_delta, lhs.tv_sec + rhs.tv_sec,
71 				lhs.tv_nsec + rhs.tv_nsec);
72 	return ts_delta;
73 }
74 
75 /*
76  * sub = lhs - rhs, in normalized form
77  */
78 static inline struct timespec timespec_sub(struct timespec lhs,
79 						struct timespec rhs)
80 {
81 	struct timespec ts_delta;
82 	set_normalized_timespec(&ts_delta, lhs.tv_sec - rhs.tv_sec,
83 				lhs.tv_nsec - rhs.tv_nsec);
84 	return ts_delta;
85 }
86 
87 #define KTIME_MAX			((s64)~((u64)1 << 63))
88 #if (BITS_PER_LONG == 64)
89 # define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
90 #else
91 # define KTIME_SEC_MAX			LONG_MAX
92 #endif
93 
94 /*
95  * Returns true if the timespec is norm, false if denorm:
96  */
97 static inline bool timespec_valid(const struct timespec *ts)
98 {
99 	/* Dates before 1970 are bogus */
100 	if (ts->tv_sec < 0)
101 		return false;
102 	/* Can't have more nanoseconds then a second */
103 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
104 		return false;
105 	return true;
106 }
107 
108 static inline bool timespec_valid_strict(const struct timespec *ts)
109 {
110 	if (!timespec_valid(ts))
111 		return false;
112 	/* Disallow values that could overflow ktime_t */
113 	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
114 		return false;
115 	return true;
116 }
117 
118 extern bool persistent_clock_exist;
119 
120 #ifdef ALWAYS_USE_PERSISTENT_CLOCK
121 #define has_persistent_clock()	true
122 #else
123 static inline bool has_persistent_clock(void)
124 {
125 	return persistent_clock_exist;
126 }
127 #endif
128 
129 extern void read_persistent_clock(struct timespec *ts);
130 extern void read_boot_clock(struct timespec *ts);
131 extern int persistent_clock_is_local;
132 extern int update_persistent_clock(struct timespec now);
133 void timekeeping_init(void);
134 extern int timekeeping_suspended;
135 
136 unsigned long get_seconds(void);
137 struct timespec current_kernel_time(void);
138 struct timespec __current_kernel_time(void); /* does not take xtime_lock */
139 struct timespec get_monotonic_coarse(void);
140 void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim,
141 				struct timespec *wtom, struct timespec *sleep);
142 void timekeeping_inject_sleeptime(struct timespec *delta);
143 
144 #define CURRENT_TIME		(current_kernel_time())
145 #define CURRENT_TIME_SEC	((struct timespec) { get_seconds(), 0 })
146 
147 /* Some architectures do not supply their own clocksource.
148  * This is mainly the case in architectures that get their
149  * inter-tick times by reading the counter on their interval
150  * timer. Since these timers wrap every tick, they're not really
151  * useful as clocksources. Wrapping them to act like one is possible
152  * but not very efficient. So we provide a callout these arches
153  * can implement for use with the jiffies clocksource to provide
154  * finer then tick granular time.
155  */
156 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
157 extern u32 (*arch_gettimeoffset)(void);
158 #endif
159 
160 extern void do_gettimeofday(struct timeval *tv);
161 extern int do_settimeofday(const struct timespec *tv);
162 extern int do_sys_settimeofday(const struct timespec *tv,
163 			       const struct timezone *tz);
164 #define do_posix_clock_monotonic_gettime(ts) ktime_get_ts(ts)
165 extern long do_utimes(int dfd, const char __user *filename, struct timespec *times, int flags);
166 struct itimerval;
167 extern int do_setitimer(int which, struct itimerval *value,
168 			struct itimerval *ovalue);
169 extern unsigned int alarm_setitimer(unsigned int seconds);
170 extern int do_getitimer(int which, struct itimerval *value);
171 extern int __getnstimeofday(struct timespec *tv);
172 extern void getnstimeofday(struct timespec *tv);
173 extern void getrawmonotonic(struct timespec *ts);
174 extern void getnstime_raw_and_real(struct timespec *ts_raw,
175 		struct timespec *ts_real);
176 extern void getboottime(struct timespec *ts);
177 extern void monotonic_to_bootbased(struct timespec *ts);
178 extern void get_monotonic_boottime(struct timespec *ts);
179 
180 extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
181 extern int timekeeping_valid_for_hres(void);
182 extern u64 timekeeping_max_deferment(void);
183 extern int timekeeping_inject_offset(struct timespec *ts);
184 
185 struct tms;
186 extern void do_sys_times(struct tms *);
187 
188 /*
189  * Similar to the struct tm in userspace <time.h>, but it needs to be here so
190  * that the kernel source is self contained.
191  */
192 struct tm {
193 	/*
194 	 * the number of seconds after the minute, normally in the range
195 	 * 0 to 59, but can be up to 60 to allow for leap seconds
196 	 */
197 	int tm_sec;
198 	/* the number of minutes after the hour, in the range 0 to 59*/
199 	int tm_min;
200 	/* the number of hours past midnight, in the range 0 to 23 */
201 	int tm_hour;
202 	/* the day of the month, in the range 1 to 31 */
203 	int tm_mday;
204 	/* the number of months since January, in the range 0 to 11 */
205 	int tm_mon;
206 	/* the number of years since 1900 */
207 	long tm_year;
208 	/* the number of days since Sunday, in the range 0 to 6 */
209 	int tm_wday;
210 	/* the number of days since January 1, in the range 0 to 365 */
211 	int tm_yday;
212 };
213 
214 void time_to_tm(time_t totalsecs, int offset, struct tm *result);
215 
216 /**
217  * timespec_to_ns - Convert timespec to nanoseconds
218  * @ts:		pointer to the timespec variable to be converted
219  *
220  * Returns the scalar nanosecond representation of the timespec
221  * parameter.
222  */
223 static inline s64 timespec_to_ns(const struct timespec *ts)
224 {
225 	return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
226 }
227 
228 /**
229  * timeval_to_ns - Convert timeval to nanoseconds
230  * @ts:		pointer to the timeval variable to be converted
231  *
232  * Returns the scalar nanosecond representation of the timeval
233  * parameter.
234  */
235 static inline s64 timeval_to_ns(const struct timeval *tv)
236 {
237 	return ((s64) tv->tv_sec * NSEC_PER_SEC) +
238 		tv->tv_usec * NSEC_PER_USEC;
239 }
240 
241 /**
242  * ns_to_timespec - Convert nanoseconds to timespec
243  * @nsec:	the nanoseconds value to be converted
244  *
245  * Returns the timespec representation of the nsec parameter.
246  */
247 extern struct timespec ns_to_timespec(const s64 nsec);
248 
249 /**
250  * ns_to_timeval - Convert nanoseconds to timeval
251  * @nsec:	the nanoseconds value to be converted
252  *
253  * Returns the timeval representation of the nsec parameter.
254  */
255 extern struct timeval ns_to_timeval(const s64 nsec);
256 
257 /**
258  * timespec_add_ns - Adds nanoseconds to a timespec
259  * @a:		pointer to timespec to be incremented
260  * @ns:		unsigned nanoseconds value to be added
261  *
262  * This must always be inlined because its used from the x86-64 vdso,
263  * which cannot call other kernel functions.
264  */
265 static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
266 {
267 	a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
268 	a->tv_nsec = ns;
269 }
270 
271 #endif
272