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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