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97fc79f9 TG |
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 | * | |
66188fae TG |
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 | * | |
97fc79f9 TG |
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 | typedef union { | |
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 | } ktime_t; | |
58 | ||
59 | #define KTIME_MAX (~((u64)1 << 63)) | |
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 | ||
97fc79f9 TG |
67 | /** |
68 | * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value | |
69 | * | |
70 | * @secs: seconds to set | |
71 | * @nsecs: nanoseconds to set | |
72 | * | |
73 | * Return the ktime_t representation of the value | |
74 | */ | |
75 | static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) | |
76 | { | |
77 | return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs }; | |
78 | } | |
79 | ||
80 | /* Subtract two ktime_t variables. rem = lhs -rhs: */ | |
81 | #define ktime_sub(lhs, rhs) \ | |
82 | ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; }) | |
83 | ||
84 | /* Add two ktime_t variables. res = lhs + rhs: */ | |
85 | #define ktime_add(lhs, rhs) \ | |
86 | ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; }) | |
87 | ||
88 | /* | |
89 | * Add a ktime_t variable and a scalar nanosecond value. | |
90 | * res = kt + nsval: | |
91 | */ | |
92 | #define ktime_add_ns(kt, nsval) \ | |
93 | ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; }) | |
94 | ||
95 | /* convert a timespec to ktime_t format: */ | |
b2ee9dbf RZ |
96 | static inline ktime_t timespec_to_ktime(struct timespec ts) |
97 | { | |
98 | return ktime_set(ts.tv_sec, ts.tv_nsec); | |
99 | } | |
97fc79f9 TG |
100 | |
101 | /* convert a timeval to ktime_t format: */ | |
b2ee9dbf RZ |
102 | static inline ktime_t timeval_to_ktime(struct timeval tv) |
103 | { | |
104 | return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC); | |
105 | } | |
97fc79f9 TG |
106 | |
107 | /* Map the ktime_t to timespec conversion to ns_to_timespec function */ | |
108 | #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64) | |
109 | ||
110 | /* Map the ktime_t to timeval conversion to ns_to_timeval function */ | |
111 | #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64) | |
112 | ||
97fc79f9 TG |
113 | /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */ |
114 | #define ktime_to_ns(kt) ((kt).tv64) | |
115 | ||
116 | #else | |
117 | ||
118 | /* | |
119 | * Helper macros/inlines to get the ktime_t math right in the timespec | |
120 | * representation. The macros are sometimes ugly - their actual use is | |
121 | * pretty okay-ish, given the circumstances. We do all this for | |
122 | * performance reasons. The pure scalar nsec_t based code was nice and | |
123 | * simple, but created too many 64-bit / 32-bit conversions and divisions. | |
124 | * | |
125 | * Be especially aware that negative values are represented in a way | |
126 | * that the tv.sec field is negative and the tv.nsec field is greater | |
127 | * or equal to zero but less than nanoseconds per second. This is the | |
128 | * same representation which is used by timespecs. | |
129 | * | |
130 | * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC | |
131 | */ | |
132 | ||
97fc79f9 TG |
133 | /* Set a ktime_t variable to a value in sec/nsec representation: */ |
134 | static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) | |
135 | { | |
136 | return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } }; | |
137 | } | |
138 | ||
139 | /** | |
140 | * ktime_sub - subtract two ktime_t variables | |
141 | * | |
142 | * @lhs: minuend | |
143 | * @rhs: subtrahend | |
144 | * | |
145 | * Returns the remainder of the substraction | |
146 | */ | |
147 | static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs) | |
148 | { | |
149 | ktime_t res; | |
150 | ||
151 | res.tv64 = lhs.tv64 - rhs.tv64; | |
152 | if (res.tv.nsec < 0) | |
153 | res.tv.nsec += NSEC_PER_SEC; | |
154 | ||
155 | return res; | |
156 | } | |
157 | ||
158 | /** | |
159 | * ktime_add - add two ktime_t variables | |
160 | * | |
161 | * @add1: addend1 | |
162 | * @add2: addend2 | |
163 | * | |
164 | * Returns the sum of addend1 and addend2 | |
165 | */ | |
166 | static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2) | |
167 | { | |
168 | ktime_t res; | |
169 | ||
170 | res.tv64 = add1.tv64 + add2.tv64; | |
171 | /* | |
172 | * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx | |
173 | * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit. | |
174 | * | |
175 | * it's equivalent to: | |
176 | * tv.nsec -= NSEC_PER_SEC | |
177 | * tv.sec ++; | |
178 | */ | |
179 | if (res.tv.nsec >= NSEC_PER_SEC) | |
180 | res.tv64 += (u32)-NSEC_PER_SEC; | |
181 | ||
182 | return res; | |
183 | } | |
184 | ||
185 | /** | |
186 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable | |
187 | * | |
188 | * @kt: addend | |
189 | * @nsec: the scalar nsec value to add | |
190 | * | |
191 | * Returns the sum of kt and nsec in ktime_t format | |
192 | */ | |
193 | extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec); | |
194 | ||
195 | /** | |
196 | * timespec_to_ktime - convert a timespec to ktime_t format | |
197 | * | |
198 | * @ts: the timespec variable to convert | |
199 | * | |
200 | * Returns a ktime_t variable with the converted timespec value | |
201 | */ | |
202 | static inline ktime_t timespec_to_ktime(const struct timespec ts) | |
203 | { | |
204 | return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec, | |
205 | .nsec = (s32)ts.tv_nsec } }; | |
206 | } | |
207 | ||
208 | /** | |
209 | * timeval_to_ktime - convert a timeval to ktime_t format | |
210 | * | |
211 | * @tv: the timeval variable to convert | |
212 | * | |
213 | * Returns a ktime_t variable with the converted timeval value | |
214 | */ | |
215 | static inline ktime_t timeval_to_ktime(const struct timeval tv) | |
216 | { | |
217 | return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec, | |
218 | .nsec = (s32)tv.tv_usec * 1000 } }; | |
219 | } | |
220 | ||
221 | /** | |
222 | * ktime_to_timespec - convert a ktime_t variable to timespec format | |
223 | * | |
224 | * @kt: the ktime_t variable to convert | |
225 | * | |
226 | * Returns the timespec representation of the ktime value | |
227 | */ | |
228 | static inline struct timespec ktime_to_timespec(const ktime_t kt) | |
229 | { | |
230 | return (struct timespec) { .tv_sec = (time_t) kt.tv.sec, | |
231 | .tv_nsec = (long) kt.tv.nsec }; | |
232 | } | |
233 | ||
234 | /** | |
235 | * ktime_to_timeval - convert a ktime_t variable to timeval format | |
236 | * | |
237 | * @kt: the ktime_t variable to convert | |
238 | * | |
239 | * Returns the timeval representation of the ktime value | |
240 | */ | |
241 | static inline struct timeval ktime_to_timeval(const ktime_t kt) | |
242 | { | |
243 | return (struct timeval) { | |
244 | .tv_sec = (time_t) kt.tv.sec, | |
245 | .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) }; | |
246 | } | |
247 | ||
97fc79f9 TG |
248 | /** |
249 | * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds | |
250 | * @kt: the ktime_t variable to convert | |
251 | * | |
252 | * Returns the scalar nanoseconds representation of kt | |
253 | */ | |
254 | static inline u64 ktime_to_ns(const ktime_t kt) | |
255 | { | |
256 | return (u64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec; | |
257 | } | |
258 | ||
259 | #endif | |
260 | ||
c0a31329 TG |
261 | /* |
262 | * The resolution of the clocks. The resolution value is returned in | |
263 | * the clock_getres() system call to give application programmers an | |
264 | * idea of the (in)accuracy of timers. Timer values are rounded up to | |
265 | * this resolution values. | |
266 | */ | |
e2787630 TG |
267 | #define KTIME_REALTIME_RES (ktime_t){ .tv64 = TICK_NSEC } |
268 | #define KTIME_MONOTONIC_RES (ktime_t){ .tv64 = TICK_NSEC } | |
c0a31329 TG |
269 | |
270 | /* Get the monotonic time in timespec format: */ | |
271 | extern void ktime_get_ts(struct timespec *ts); | |
272 | ||
273 | /* Get the real (wall-) time in timespec format: */ | |
274 | #define ktime_get_real_ts(ts) getnstimeofday(ts) | |
275 | ||
97fc79f9 | 276 | #endif |