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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 choosen 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 | #define KTIME_MAX ((s64)~((u64)1 << 63)) |
62 | #if (BITS_PER_LONG == 64) |
63 | # define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC) |
64 | #else |
65 | # define KTIME_SEC_MAX LONG_MAX |
66 | #endif |
67 | |
68 | /* |
69 | * ktime_t definitions when using the 64-bit scalar representation: |
70 | */ |
71 | |
72 | #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR) |
73 | |
74 | /** |
75 | * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value |
76 | * @secs: seconds to set |
77 | * @nsecs: nanoseconds to set |
78 | * |
79 | * Return the ktime_t representation of the value |
80 | */ |
81 | static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) |
82 | { |
83 | #if (BITS_PER_LONG == 64) |
84 | if (unlikely(secs >= KTIME_SEC_MAX)) |
85 | return (ktime_t){ .tv64 = KTIME_MAX }; |
86 | #endif |
87 | return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs }; |
88 | } |
89 | |
90 | /* Subtract two ktime_t variables. rem = lhs -rhs: */ |
91 | #define ktime_sub(lhs, rhs) \ |
92 | ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; }) |
93 | |
94 | /* Add two ktime_t variables. res = lhs + rhs: */ |
95 | #define ktime_add(lhs, rhs) \ |
96 | ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; }) |
97 | |
98 | /* |
99 | * Add a ktime_t variable and a scalar nanosecond value. |
100 | * res = kt + nsval: |
101 | */ |
102 | #define ktime_add_ns(kt, nsval) \ |
103 | ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; }) |
104 | |
105 | /* |
106 | * Subtract a scalar nanosecod from a ktime_t variable |
107 | * res = kt - nsval: |
108 | */ |
109 | #define ktime_sub_ns(kt, nsval) \ |
110 | ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; }) |
111 | |
112 | /* convert a timespec to ktime_t format: */ |
113 | static inline ktime_t timespec_to_ktime(struct timespec ts) |
114 | { |
115 | return ktime_set(ts.tv_sec, ts.tv_nsec); |
116 | } |
117 | |
118 | /* convert a timeval to ktime_t format: */ |
119 | static inline ktime_t timeval_to_ktime(struct timeval tv) |
120 | { |
121 | return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC); |
122 | } |
123 | |
124 | /* Map the ktime_t to timespec conversion to ns_to_timespec function */ |
125 | #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64) |
126 | |
127 | /* Map the ktime_t to timeval conversion to ns_to_timeval function */ |
128 | #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64) |
129 | |
130 | /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */ |
131 | #define ktime_to_ns(kt) ((kt).tv64) |
132 | |
133 | #else |
134 | |
135 | /* |
136 | * Helper macros/inlines to get the ktime_t math right in the timespec |
137 | * representation. The macros are sometimes ugly - their actual use is |
138 | * pretty okay-ish, given the circumstances. We do all this for |
139 | * performance reasons. The pure scalar nsec_t based code was nice and |
140 | * simple, but created too many 64-bit / 32-bit conversions and divisions. |
141 | * |
142 | * Be especially aware that negative values are represented in a way |
143 | * that the tv.sec field is negative and the tv.nsec field is greater |
144 | * or equal to zero but less than nanoseconds per second. This is the |
145 | * same representation which is used by timespecs. |
146 | * |
147 | * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC |
148 | */ |
149 | |
150 | /* Set a ktime_t variable to a value in sec/nsec representation: */ |
151 | static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) |
152 | { |
153 | return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } }; |
154 | } |
155 | |
156 | /** |
157 | * ktime_sub - subtract two ktime_t variables |
158 | * @lhs: minuend |
159 | * @rhs: subtrahend |
160 | * |
161 | * Returns the remainder of the substraction |
162 | */ |
163 | static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs) |
164 | { |
165 | ktime_t res; |
166 | |
167 | res.tv64 = lhs.tv64 - rhs.tv64; |
168 | if (res.tv.nsec < 0) |
169 | res.tv.nsec += NSEC_PER_SEC; |
170 | |
171 | return res; |
172 | } |
173 | |
174 | /** |
175 | * ktime_add - add two ktime_t variables |
176 | * @add1: addend1 |
177 | * @add2: addend2 |
178 | * |
179 | * Returns the sum of @add1 and @add2. |
180 | */ |
181 | static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2) |
182 | { |
183 | ktime_t res; |
184 | |
185 | res.tv64 = add1.tv64 + add2.tv64; |
186 | /* |
187 | * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx |
188 | * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit. |
189 | * |
190 | * it's equivalent to: |
191 | * tv.nsec -= NSEC_PER_SEC |
192 | * tv.sec ++; |
193 | */ |
194 | if (res.tv.nsec >= NSEC_PER_SEC) |
195 | res.tv64 += (u32)-NSEC_PER_SEC; |
196 | |
197 | return res; |
198 | } |
199 | |
200 | /** |
201 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable |
202 | * @kt: addend |
203 | * @nsec: the scalar nsec value to add |
204 | * |
205 | * Returns the sum of @kt and @nsec in ktime_t format |
206 | */ |
207 | extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec); |
208 | |
209 | /** |
210 | * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable |
211 | * @kt: minuend |
212 | * @nsec: the scalar nsec value to subtract |
213 | * |
214 | * Returns the subtraction of @nsec from @kt in ktime_t format |
215 | */ |
216 | extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec); |
217 | |
218 | /** |
219 | * timespec_to_ktime - convert a timespec to ktime_t format |
220 | * @ts: the timespec variable to convert |
221 | * |
222 | * Returns a ktime_t variable with the converted timespec value |
223 | */ |
224 | static inline ktime_t timespec_to_ktime(const struct timespec ts) |
225 | { |
226 | return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec, |
227 | .nsec = (s32)ts.tv_nsec } }; |
228 | } |
229 | |
230 | /** |
231 | * timeval_to_ktime - convert a timeval to ktime_t format |
232 | * @tv: the timeval variable to convert |
233 | * |
234 | * Returns a ktime_t variable with the converted timeval value |
235 | */ |
236 | static inline ktime_t timeval_to_ktime(const struct timeval tv) |
237 | { |
238 | return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec, |
239 | .nsec = (s32)tv.tv_usec * 1000 } }; |
240 | } |
241 | |
242 | /** |
243 | * ktime_to_timespec - convert a ktime_t variable to timespec format |
244 | * @kt: the ktime_t variable to convert |
245 | * |
246 | * Returns the timespec representation of the ktime value |
247 | */ |
248 | static inline struct timespec ktime_to_timespec(const ktime_t kt) |
249 | { |
250 | return (struct timespec) { .tv_sec = (time_t) kt.tv.sec, |
251 | .tv_nsec = (long) kt.tv.nsec }; |
252 | } |
253 | |
254 | /** |
255 | * ktime_to_timeval - convert a ktime_t variable to timeval format |
256 | * @kt: the ktime_t variable to convert |
257 | * |
258 | * Returns the timeval representation of the ktime value |
259 | */ |
260 | static inline struct timeval ktime_to_timeval(const ktime_t kt) |
261 | { |
262 | return (struct timeval) { |
263 | .tv_sec = (time_t) kt.tv.sec, |
264 | .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) }; |
265 | } |
266 | |
267 | /** |
268 | * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds |
269 | * @kt: the ktime_t variable to convert |
270 | * |
271 | * Returns the scalar nanoseconds representation of @kt |
272 | */ |
273 | static inline s64 ktime_to_ns(const ktime_t kt) |
274 | { |
275 | return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec; |
276 | } |
277 | |
278 | #endif |
279 | |
280 | /** |
281 | * ktime_equal - Compares two ktime_t variables to see if they are equal |
282 | * @cmp1: comparable1 |
283 | * @cmp2: comparable2 |
284 | * |
285 | * Compare two ktime_t variables, returns 1 if equal |
286 | */ |
287 | static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2) |
288 | { |
289 | return cmp1.tv64 == cmp2.tv64; |
290 | } |
291 | |
292 | static inline s64 ktime_to_us(const ktime_t kt) |
293 | { |
294 | struct timeval tv = ktime_to_timeval(kt); |
295 | return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec; |
296 | } |
297 | |
298 | static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier) |
299 | { |
300 | return ktime_to_us(ktime_sub(later, earlier)); |
301 | } |
302 | |
303 | static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec) |
304 | { |
305 | return ktime_add_ns(kt, usec * 1000); |
306 | } |
307 | |
308 | static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec) |
309 | { |
310 | return ktime_sub_ns(kt, usec * 1000); |
311 | } |
312 | |
313 | extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs); |
314 | |
315 | /* |
316 | * The resolution of the clocks. The resolution value is returned in |
317 | * the clock_getres() system call to give application programmers an |
318 | * idea of the (in)accuracy of timers. Timer values are rounded up to |
319 | * this resolution values. |
320 | */ |
321 | #define LOW_RES_NSEC TICK_NSEC |
322 | #define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC } |
323 | |
324 | /* Get the monotonic time in timespec format: */ |
325 | extern void ktime_get_ts(struct timespec *ts); |
326 | |
327 | /* Get the real (wall-) time in timespec format: */ |
328 | #define ktime_get_real_ts(ts) getnstimeofday(ts) |
329 | |
330 | static inline ktime_t ns_to_ktime(u64 ns) |
331 | { |
332 | static const ktime_t ktime_zero = { .tv64 = 0 }; |
333 | return ktime_add_ns(ktime_zero, ns); |
334 | } |
335 | |
336 | #endif |
337 |
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