1/*
2 * include/linux/ktime.h
3 *
4 * ktime_t - nanosecond-resolution time format.
5 *
6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
8 *
9 * data type definitions, declarations, prototypes and macros.
10 *
11 * Started by: Thomas Gleixner and Ingo Molnar
12 *
13 * Credits:
14 *
15 * Roman Zippel provided the ideas and primary code snippets of
16 * the ktime_t union and further simplifications of the original
17 * code.
18 *
19 * For licencing details see kernel-base/COPYING
20 */
21#ifndef _LINUX_KTIME_H
22#define _LINUX_KTIME_H
23
24#include <linux/time.h>
25#include <linux/jiffies.h>
26#include <asm/bug.h>
27
28/* Nanosecond scalar representation for kernel time values */
29typedef s64 ktime_t;
30
31/**
32 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
33 * @secs: seconds to set
34 * @nsecs: nanoseconds to set
35 *
36 * Return: The ktime_t representation of the value.
37 */
38static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
39{
40 if (unlikely(secs >= KTIME_SEC_MAX))
41 return KTIME_MAX;
42
43 return secs * NSEC_PER_SEC + (s64)nsecs;
44}
45
46/* Subtract two ktime_t variables. rem = lhs -rhs: */
47#define ktime_sub(lhs, rhs) ((lhs) - (rhs))
48
49/* Add two ktime_t variables. res = lhs + rhs: */
50#define ktime_add(lhs, rhs) ((lhs) + (rhs))
51
52/*
53 * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
54 * this means that you must check the result for overflow yourself.
55 */
56#define ktime_add_unsafe(lhs, rhs) ((u64) (lhs) + (rhs))
57
58/*
59 * Add a ktime_t variable and a scalar nanosecond value.
60 * res = kt + nsval:
61 */
62#define ktime_add_ns(kt, nsval) ((kt) + (nsval))
63
64/*
65 * Subtract a scalar nanosecod from a ktime_t variable
66 * res = kt - nsval:
67 */
68#define ktime_sub_ns(kt, nsval) ((kt) - (nsval))
69
70/* convert a timespec64 to ktime_t format: */
71static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
72{
73 return ktime_set(ts.tv_sec, ts.tv_nsec);
74}
75
76/* Map the ktime_t to timespec conversion to ns_to_timespec function */
77#define ktime_to_timespec64(kt) ns_to_timespec64((kt))
78
79/* Convert ktime_t to nanoseconds */
80static inline s64 ktime_to_ns(const ktime_t kt)
81{
82 return kt;
83}
84
85/**
86 * ktime_compare - Compares two ktime_t variables for less, greater or equal
87 * @cmp1: comparable1
88 * @cmp2: comparable2
89 *
90 * Return: ...
91 * cmp1 < cmp2: return <0
92 * cmp1 == cmp2: return 0
93 * cmp1 > cmp2: return >0
94 */
95static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
96{
97 if (cmp1 < cmp2)
98 return -1;
99 if (cmp1 > cmp2)
100 return 1;
101 return 0;
102}
103
104/**
105 * ktime_after - Compare if a ktime_t value is bigger than another one.
106 * @cmp1: comparable1
107 * @cmp2: comparable2
108 *
109 * Return: true if cmp1 happened after cmp2.
110 */
111static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
112{
113 return ktime_compare(cmp1, cmp2) > 0;
114}
115
116/**
117 * ktime_before - Compare if a ktime_t value is smaller than another one.
118 * @cmp1: comparable1
119 * @cmp2: comparable2
120 *
121 * Return: true if cmp1 happened before cmp2.
122 */
123static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
124{
125 return ktime_compare(cmp1, cmp2) < 0;
126}
127
128#if BITS_PER_LONG < 64
129extern s64 __ktime_divns(const ktime_t kt, s64 div);
130static inline s64 ktime_divns(const ktime_t kt, s64 div)
131{
132 /*
133 * Negative divisors could cause an inf loop,
134 * so bug out here.
135 */
136 BUG_ON(div < 0);
137 if (__builtin_constant_p(div) && !(div >> 32)) {
138 s64 ns = kt;
139 u64 tmp = ns < 0 ? -ns : ns;
140
141 do_div(tmp, div);
142 return ns < 0 ? -tmp : tmp;
143 } else {
144 return __ktime_divns(kt, div);
145 }
146}
147#else /* BITS_PER_LONG < 64 */
148static inline s64 ktime_divns(const ktime_t kt, s64 div)
149{
150 /*
151 * 32-bit implementation cannot handle negative divisors,
152 * so catch them on 64bit as well.
153 */
154 WARN_ON(div < 0);
155 return kt / div;
156}
157#endif
158
159static inline s64 ktime_to_us(const ktime_t kt)
160{
161 return ktime_divns(kt, NSEC_PER_USEC);
162}
163
164static inline s64 ktime_to_ms(const ktime_t kt)
165{
166 return ktime_divns(kt, NSEC_PER_MSEC);
167}
168
169static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
170{
171 return ktime_to_us(ktime_sub(later, earlier));
172}
173
174static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
175{
176 return ktime_to_ms(ktime_sub(later, earlier));
177}
178
179static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
180{
181 return ktime_add_ns(kt, usec * NSEC_PER_USEC);
182}
183
184static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
185{
186 return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
187}
188
189static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
190{
191 return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
192}
193
194static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
195{
196 return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
197}
198
199extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
200
201/**
202 * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
203 * format only if the variable contains data
204 * @kt: the ktime_t variable to convert
205 * @ts: the timespec variable to store the result in
206 *
207 * Return: %true if there was a successful conversion, %false if kt was 0.
208 */
209static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
210 struct timespec64 *ts)
211{
212 if (kt) {
213 *ts = ktime_to_timespec64(kt);
214 return true;
215 } else {
216 return false;
217 }
218}
219
220#include <vdso/ktime.h>
221
222static inline ktime_t ns_to_ktime(u64 ns)
223{
224 return ns;
225}
226
227static inline ktime_t ms_to_ktime(u64 ms)
228{
229 return ms * NSEC_PER_MSEC;
230}
231
232# include <linux/timekeeping.h>
233
234#endif
235

source code of linux/include/linux/ktime.h