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 <asm/bug.h>
25#include <linux/jiffies.h>
26#include <linux/time.h>
27#include <linux/types.h>
28
29/**
30 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
31 * @secs: seconds to set
32 * @nsecs: nanoseconds to set
33 *
34 * Return: The ktime_t representation of the value.
35 */
36static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
37{
38 if (unlikely(secs >= KTIME_SEC_MAX))
39 return KTIME_MAX;
40
41 return secs * NSEC_PER_SEC + (s64)nsecs;
42}
43
44/* Subtract two ktime_t variables. rem = lhs -rhs: */
45#define ktime_sub(lhs, rhs) ((lhs) - (rhs))
46
47/* Add two ktime_t variables. res = lhs + rhs: */
48#define ktime_add(lhs, rhs) ((lhs) + (rhs))
49
50/*
51 * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
52 * this means that you must check the result for overflow yourself.
53 */
54#define ktime_add_unsafe(lhs, rhs) ((u64) (lhs) + (rhs))
55
56/*
57 * Add a ktime_t variable and a scalar nanosecond value.
58 * res = kt + nsval:
59 */
60#define ktime_add_ns(kt, nsval) ((kt) + (nsval))
61
62/*
63 * Subtract a scalar nanosecod from a ktime_t variable
64 * res = kt - nsval:
65 */
66#define ktime_sub_ns(kt, nsval) ((kt) - (nsval))
67
68/* convert a timespec64 to ktime_t format: */
69static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
70{
71 return ktime_set(secs: ts.tv_sec, nsecs: ts.tv_nsec);
72}
73
74/* Map the ktime_t to timespec conversion to ns_to_timespec function */
75#define ktime_to_timespec64(kt) ns_to_timespec64((kt))
76
77/* Convert ktime_t to nanoseconds */
78static inline s64 ktime_to_ns(const ktime_t kt)
79{
80 return kt;
81}
82
83/**
84 * ktime_compare - Compares two ktime_t variables for less, greater or equal
85 * @cmp1: comparable1
86 * @cmp2: comparable2
87 *
88 * Return: ...
89 * cmp1 < cmp2: return <0
90 * cmp1 == cmp2: return 0
91 * cmp1 > cmp2: return >0
92 */
93static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
94{
95 if (cmp1 < cmp2)
96 return -1;
97 if (cmp1 > cmp2)
98 return 1;
99 return 0;
100}
101
102/**
103 * ktime_after - Compare if a ktime_t value is bigger than another one.
104 * @cmp1: comparable1
105 * @cmp2: comparable2
106 *
107 * Return: true if cmp1 happened after cmp2.
108 */
109static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
110{
111 return ktime_compare(cmp1, cmp2) > 0;
112}
113
114/**
115 * ktime_before - Compare if a ktime_t value is smaller than another one.
116 * @cmp1: comparable1
117 * @cmp2: comparable2
118 *
119 * Return: true if cmp1 happened before cmp2.
120 */
121static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
122{
123 return ktime_compare(cmp1, cmp2) < 0;
124}
125
126#if BITS_PER_LONG < 64
127extern s64 __ktime_divns(const ktime_t kt, s64 div);
128static inline s64 ktime_divns(const ktime_t kt, s64 div)
129{
130 /*
131 * Negative divisors could cause an inf loop,
132 * so bug out here.
133 */
134 BUG_ON(div < 0);
135 if (__builtin_constant_p(div) && !(div >> 32)) {
136 s64 ns = kt;
137 u64 tmp = ns < 0 ? -ns : ns;
138
139 do_div(tmp, div);
140 return ns < 0 ? -tmp : tmp;
141 } else {
142 return __ktime_divns(kt, div);
143 }
144}
145#else /* BITS_PER_LONG < 64 */
146static inline s64 ktime_divns(const ktime_t kt, s64 div)
147{
148 /*
149 * 32-bit implementation cannot handle negative divisors,
150 * so catch them on 64bit as well.
151 */
152 WARN_ON(div < 0);
153 return kt / div;
154}
155#endif
156
157static inline s64 ktime_to_us(const ktime_t kt)
158{
159 return ktime_divns(kt, NSEC_PER_USEC);
160}
161
162static inline s64 ktime_to_ms(const ktime_t kt)
163{
164 return ktime_divns(kt, NSEC_PER_MSEC);
165}
166
167static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
168{
169 return ktime_to_us(ktime_sub(later, earlier));
170}
171
172static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
173{
174 return ktime_to_ms(ktime_sub(later, earlier));
175}
176
177static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
178{
179 return ktime_add_ns(kt, usec * NSEC_PER_USEC);
180}
181
182static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
183{
184 return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
185}
186
187static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
188{
189 return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
190}
191
192static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
193{
194 return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
195}
196
197extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
198
199/**
200 * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
201 * format only if the variable contains data
202 * @kt: the ktime_t variable to convert
203 * @ts: the timespec variable to store the result in
204 *
205 * Return: %true if there was a successful conversion, %false if kt was 0.
206 */
207static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
208 struct timespec64 *ts)
209{
210 if (kt) {
211 *ts = ktime_to_timespec64(kt);
212 return true;
213 } else {
214 return false;
215 }
216}
217
218#include <vdso/ktime.h>
219
220static inline ktime_t ns_to_ktime(u64 ns)
221{
222 return ns;
223}
224
225static inline ktime_t us_to_ktime(u64 us)
226{
227 return us * NSEC_PER_USEC;
228}
229
230static inline ktime_t ms_to_ktime(u64 ms)
231{
232 return ms * NSEC_PER_MSEC;
233}
234
235# include <linux/timekeeping.h>
236
237#endif
238

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

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