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
27 /*
28 * ktime_t:
29 *
30 * On 64-bit CPUs a single 64-bit variable is used to store the hrtimers
31 * internal representation of time values in scalar nanoseconds. The
32 * design plays out best on 64-bit CPUs, where most conversions are
33 * NOPs and most arithmetic ktime_t operations are plain arithmetic
34 * operations.
35 *
36 * On 32-bit CPUs an optimized representation of the timespec structure
37 * is used to avoid expensive conversions from and to timespecs. The
38 * endian-aware order of the tv struct members is chosen to allow
39 * mathematical operations on the tv64 member of the union too, which
40 * for certain operations produces better code.
41 *
42 * For architectures with efficient support for 64/32-bit conversions the
43 * plain scalar nanosecond based representation can be selected by the
44 * config switch CONFIG_KTIME_SCALAR.
45 */
46 union ktime {
47 s64 tv64;
48 #if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
49 struct {
50 # ifdef __BIG_ENDIAN
51 s32 sec, nsec;
52 # else
53 s32 nsec, sec;
54 # endif
55 } tv;
56 #endif
57 };
58
59 typedef union ktime ktime_t; /* Kill this */
60
61 /*
62 * ktime_t definitions when using the 64-bit scalar representation:
63 */
64
65 #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
66
67 /**
68 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
69 * @secs: seconds to set
70 * @nsecs: nanoseconds to set
71 *
72 * Return the ktime_t representation of the value
73 */
ktime_set(const long secs,const unsigned long nsecs)74 static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
75 {
76 #if (BITS_PER_LONG == 64)
77 if (unlikely(secs >= KTIME_SEC_MAX))
78 return (ktime_t){ .tv64 = KTIME_MAX };
79 #endif
80 return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
81 }
82
83 /* Subtract two ktime_t variables. rem = lhs -rhs: */
84 #define ktime_sub(lhs, rhs) \
85 ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
86
87 /* Add two ktime_t variables. res = lhs + rhs: */
88 #define ktime_add(lhs, rhs) \
89 ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
90
91 /*
92 * Add a ktime_t variable and a scalar nanosecond value.
93 * res = kt + nsval:
94 */
95 #define ktime_add_ns(kt, nsval) \
96 ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
97
98 /*
99 * Subtract a scalar nanosecod from a ktime_t variable
100 * res = kt - nsval:
101 */
102 #define ktime_sub_ns(kt, nsval) \
103 ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
104
105 /* convert a timespec to ktime_t format: */
timespec_to_ktime(struct timespec ts)106 static inline ktime_t timespec_to_ktime(struct timespec ts)
107 {
108 return ktime_set(ts.tv_sec, ts.tv_nsec);
109 }
110
111 /* convert a timeval to ktime_t format: */
timeval_to_ktime(struct timeval tv)112 static inline ktime_t timeval_to_ktime(struct timeval tv)
113 {
114 return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
115 }
116
117 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
118 #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
119
120 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
121 #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
122
123 /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
124 #define ktime_to_ns(kt) ((kt).tv64)
125
126 #else /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */
127
128 /*
129 * Helper macros/inlines to get the ktime_t math right in the timespec
130 * representation. The macros are sometimes ugly - their actual use is
131 * pretty okay-ish, given the circumstances. We do all this for
132 * performance reasons. The pure scalar nsec_t based code was nice and
133 * simple, but created too many 64-bit / 32-bit conversions and divisions.
134 *
135 * Be especially aware that negative values are represented in a way
136 * that the tv.sec field is negative and the tv.nsec field is greater
137 * or equal to zero but less than nanoseconds per second. This is the
138 * same representation which is used by timespecs.
139 *
140 * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
141 */
142
143 /* Set a ktime_t variable to a value in sec/nsec representation: */
ktime_set(const long secs,const unsigned long nsecs)144 static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
145 {
146 return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };
147 }
148
149 /**
150 * ktime_sub - subtract two ktime_t variables
151 * @lhs: minuend
152 * @rhs: subtrahend
153 *
154 * Returns the remainder of the subtraction
155 */
ktime_sub(const ktime_t lhs,const ktime_t rhs)156 static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)
157 {
158 ktime_t res;
159
160 res.tv64 = lhs.tv64 - rhs.tv64;
161 if (res.tv.nsec < 0)
162 res.tv.nsec += NSEC_PER_SEC;
163
164 return res;
165 }
166
167 /**
168 * ktime_add - add two ktime_t variables
169 * @add1: addend1
170 * @add2: addend2
171 *
172 * Returns the sum of @add1 and @add2.
173 */
ktime_add(const ktime_t add1,const ktime_t add2)174 static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)
175 {
176 ktime_t res;
177
178 res.tv64 = add1.tv64 + add2.tv64;
179 /*
180 * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
181 * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
182 *
183 * it's equivalent to:
184 * tv.nsec -= NSEC_PER_SEC
185 * tv.sec ++;
186 */
187 if (res.tv.nsec >= NSEC_PER_SEC)
188 res.tv64 += (u32)-NSEC_PER_SEC;
189
190 return res;
191 }
192
193 /**
194 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
195 * @kt: addend
196 * @nsec: the scalar nsec value to add
197 *
198 * Returns the sum of @kt and @nsec in ktime_t format
199 */
200 extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);
201
202 /**
203 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
204 * @kt: minuend
205 * @nsec: the scalar nsec value to subtract
206 *
207 * Returns the subtraction of @nsec from @kt in ktime_t format
208 */
209 extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec);
210
211 /**
212 * timespec_to_ktime - convert a timespec to ktime_t format
213 * @ts: the timespec variable to convert
214 *
215 * Returns a ktime_t variable with the converted timespec value
216 */
timespec_to_ktime(const struct timespec ts)217 static inline ktime_t timespec_to_ktime(const struct timespec ts)
218 {
219 return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,
220 .nsec = (s32)ts.tv_nsec } };
221 }
222
223 /**
224 * timeval_to_ktime - convert a timeval to ktime_t format
225 * @tv: the timeval variable to convert
226 *
227 * Returns a ktime_t variable with the converted timeval value
228 */
timeval_to_ktime(const struct timeval tv)229 static inline ktime_t timeval_to_ktime(const struct timeval tv)
230 {
231 return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,
232 .nsec = (s32)tv.tv_usec * 1000 } };
233 }
234
235 /**
236 * ktime_to_timespec - convert a ktime_t variable to timespec format
237 * @kt: the ktime_t variable to convert
238 *
239 * Returns the timespec representation of the ktime value
240 */
ktime_to_timespec(const ktime_t kt)241 static inline struct timespec ktime_to_timespec(const ktime_t kt)
242 {
243 return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,
244 .tv_nsec = (long) kt.tv.nsec };
245 }
246
247 /**
248 * ktime_to_timeval - convert a ktime_t variable to timeval format
249 * @kt: the ktime_t variable to convert
250 *
251 * Returns the timeval representation of the ktime value
252 */
ktime_to_timeval(const ktime_t kt)253 static inline struct timeval ktime_to_timeval(const ktime_t kt)
254 {
255 return (struct timeval) {
256 .tv_sec = (time_t) kt.tv.sec,
257 .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };
258 }
259
260 /**
261 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
262 * @kt: the ktime_t variable to convert
263 *
264 * Returns the scalar nanoseconds representation of @kt
265 */
ktime_to_ns(const ktime_t kt)266 static inline s64 ktime_to_ns(const ktime_t kt)
267 {
268 return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;
269 }
270
271 #endif /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */
272
273 /**
274 * ktime_equal - Compares two ktime_t variables to see if they are equal
275 * @cmp1: comparable1
276 * @cmp2: comparable2
277 *
278 * Compare two ktime_t variables, returns 1 if equal
279 */
ktime_equal(const ktime_t cmp1,const ktime_t cmp2)280 static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
281 {
282 return cmp1.tv64 == cmp2.tv64;
283 }
284
285 /**
286 * ktime_compare - Compares two ktime_t variables for less, greater or equal
287 * @cmp1: comparable1
288 * @cmp2: comparable2
289 *
290 * Returns ...
291 * cmp1 < cmp2: return <0
292 * cmp1 == cmp2: return 0
293 * cmp1 > cmp2: return >0
294 */
ktime_compare(const ktime_t cmp1,const ktime_t cmp2)295 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
296 {
297 if (cmp1.tv64 < cmp2.tv64)
298 return -1;
299 if (cmp1.tv64 > cmp2.tv64)
300 return 1;
301 return 0;
302 }
303
ktime_to_us(const ktime_t kt)304 static inline s64 ktime_to_us(const ktime_t kt)
305 {
306 struct timeval tv = ktime_to_timeval(kt);
307 return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
308 }
309
ktime_to_ms(const ktime_t kt)310 static inline s64 ktime_to_ms(const ktime_t kt)
311 {
312 struct timeval tv = ktime_to_timeval(kt);
313 return (s64) tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC;
314 }
315
ktime_us_delta(const ktime_t later,const ktime_t earlier)316 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
317 {
318 return ktime_to_us(ktime_sub(later, earlier));
319 }
320
ktime_add_us(const ktime_t kt,const u64 usec)321 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
322 {
323 return ktime_add_ns(kt, usec * 1000);
324 }
325
ktime_sub_us(const ktime_t kt,const u64 usec)326 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
327 {
328 return ktime_sub_ns(kt, usec * 1000);
329 }
330
331 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
332
333 /**
334 * ktime_to_timespec_cond - convert a ktime_t variable to timespec
335 * format only if the variable contains data
336 * @kt: the ktime_t variable to convert
337 * @ts: the timespec variable to store the result in
338 *
339 * Returns true if there was a successful conversion, false if kt was 0.
340 */
ktime_to_timespec_cond(const ktime_t kt,struct timespec * ts)341 static inline bool ktime_to_timespec_cond(const ktime_t kt, struct timespec *ts)
342 {
343 if (kt.tv64) {
344 *ts = ktime_to_timespec(kt);
345 return true;
346 } else {
347 return false;
348 }
349 }
350
351 /*
352 * The resolution of the clocks. The resolution value is returned in
353 * the clock_getres() system call to give application programmers an
354 * idea of the (in)accuracy of timers. Timer values are rounded up to
355 * this resolution values.
356 */
357 #define LOW_RES_NSEC TICK_NSEC
358 #define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC }
359
360 /* Get the monotonic time in timespec format: */
361 extern void ktime_get_ts(struct timespec *ts);
362
363 /* Get the real (wall-) time in timespec format: */
364 #define ktime_get_real_ts(ts) getnstimeofday(ts)
365
ns_to_ktime(u64 ns)366 static inline ktime_t ns_to_ktime(u64 ns)
367 {
368 static const ktime_t ktime_zero = { .tv64 = 0 };
369 return ktime_add_ns(ktime_zero, ns);
370 }
371
372 #endif
373