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 */ 46union 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 59typedef 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 */ 74static 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: */ 106static 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: */ 112static 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: */ 144static 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 */ 156static 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 */ 174static 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 */ 200extern 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 */ 209extern 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 */ 217static 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 */ 229static 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 */ 241static 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 */ 253static 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 */ 266static 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 */ 280static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2) 281{ 282 return cmp1.tv64 == cmp2.tv64; 283} 284 285static inline s64 ktime_to_us(const ktime_t kt) 286{ 287 struct timeval tv = ktime_to_timeval(kt); 288 return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec; 289} 290 291static inline s64 ktime_to_ms(const ktime_t kt) 292{ 293 struct timeval tv = ktime_to_timeval(kt); 294 return (s64) tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC; 295} 296 297static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier) 298{ 299 return ktime_to_us(ktime_sub(later, earlier)); 300} 301 302static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec) 303{ 304 return ktime_add_ns(kt, usec * 1000); 305} 306 307static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec) 308{ 309 return ktime_sub_ns(kt, usec * 1000); 310} 311 312extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs); 313 314/* 315 * The resolution of the clocks. The resolution value is returned in 316 * the clock_getres() system call to give application programmers an 317 * idea of the (in)accuracy of timers. Timer values are rounded up to 318 * this resolution values. 319 */ 320#define LOW_RES_NSEC TICK_NSEC 321#define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC } 322 323/* Get the monotonic time in timespec format: */ 324extern void ktime_get_ts(struct timespec *ts); 325 326/* Get the real (wall-) time in timespec format: */ 327#define ktime_get_real_ts(ts) getnstimeofday(ts) 328 329static inline ktime_t ns_to_ktime(u64 ns) 330{ 331 static const ktime_t ktime_zero = { .tv64 = 0 }; 332 return ktime_add_ns(ktime_zero, ns); 333} 334 335#endif 336