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 */ 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#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 */ 81static 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: */ 113static 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: */ 119static 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 /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */ 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: */ 151static 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 */ 163static 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 */ 181static 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 */ 207extern 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 */ 216extern 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 */ 224static 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 */ 236static 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 */ 248static 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 */ 260static 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 */ 273static 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 /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */ 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 */ 287static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2) 288{ 289 return cmp1.tv64 == cmp2.tv64; 290} 291 292static 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 298static inline s64 ktime_to_ms(const ktime_t kt) 299{ 300 struct timeval tv = ktime_to_timeval(kt); 301 return (s64) tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC; 302} 303 304static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier) 305{ 306 return ktime_to_us(ktime_sub(later, earlier)); 307} 308 309static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec) 310{ 311 return ktime_add_ns(kt, usec * 1000); 312} 313 314static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec) 315{ 316 return ktime_sub_ns(kt, usec * 1000); 317} 318 319extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs); 320 321/* 322 * The resolution of the clocks. The resolution value is returned in 323 * the clock_getres() system call to give application programmers an 324 * idea of the (in)accuracy of timers. Timer values are rounded up to 325 * this resolution values. 326 */ 327#define LOW_RES_NSEC TICK_NSEC 328#define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC } 329 330/* Get the monotonic time in timespec format: */ 331extern void ktime_get_ts(struct timespec *ts); 332 333/* Get the real (wall-) time in timespec format: */ 334#define ktime_get_real_ts(ts) getnstimeofday(ts) 335 336static inline ktime_t ns_to_ktime(u64 ns) 337{ 338 static const ktime_t ktime_zero = { .tv64 = 0 }; 339 return ktime_add_ns(ktime_zero, ns); 340} 341 342#endif 343