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 /* convert a timespec to ktime_t format: */ 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: */ 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 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: */ 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 substraction 155 */ 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 */ 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 * timespec_to_ktime - convert a timespec to ktime_t format 204 * @ts: the timespec variable to convert 205 * 206 * Returns a ktime_t variable with the converted timespec value 207 */ 208 static inline ktime_t timespec_to_ktime(const struct timespec ts) 209 { 210 return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec, 211 .nsec = (s32)ts.tv_nsec } }; 212 } 213 214 /** 215 * timeval_to_ktime - convert a timeval to ktime_t format 216 * @tv: the timeval variable to convert 217 * 218 * Returns a ktime_t variable with the converted timeval value 219 */ 220 static inline ktime_t timeval_to_ktime(const struct timeval tv) 221 { 222 return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec, 223 .nsec = (s32)tv.tv_usec * 1000 } }; 224 } 225 226 /** 227 * ktime_to_timespec - convert a ktime_t variable to timespec format 228 * @kt: the ktime_t variable to convert 229 * 230 * Returns the timespec representation of the ktime value 231 */ 232 static inline struct timespec ktime_to_timespec(const ktime_t kt) 233 { 234 return (struct timespec) { .tv_sec = (time_t) kt.tv.sec, 235 .tv_nsec = (long) kt.tv.nsec }; 236 } 237 238 /** 239 * ktime_to_timeval - convert a ktime_t variable to timeval format 240 * @kt: the ktime_t variable to convert 241 * 242 * Returns the timeval representation of the ktime value 243 */ 244 static inline struct timeval ktime_to_timeval(const ktime_t kt) 245 { 246 return (struct timeval) { 247 .tv_sec = (time_t) kt.tv.sec, 248 .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) }; 249 } 250 251 /** 252 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds 253 * @kt: the ktime_t variable to convert 254 * 255 * Returns the scalar nanoseconds representation of @kt 256 */ 257 static inline s64 ktime_to_ns(const ktime_t kt) 258 { 259 return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec; 260 } 261 262 #endif 263 264 static inline s64 ktime_to_us(const ktime_t kt) 265 { 266 struct timeval tv = ktime_to_timeval(kt); 267 return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec; 268 } 269 270 /* 271 * The resolution of the clocks. The resolution value is returned in 272 * the clock_getres() system call to give application programmers an 273 * idea of the (in)accuracy of timers. Timer values are rounded up to 274 * this resolution values. 275 */ 276 #define KTIME_LOW_RES (ktime_t){ .tv64 = TICK_NSEC } 277 278 /* Get the monotonic time in timespec format: */ 279 extern void ktime_get_ts(struct timespec *ts); 280 281 /* Get the real (wall-) time in timespec format: */ 282 #define ktime_get_real_ts(ts) getnstimeofday(ts) 283 284 #endif 285