Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/time.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * |
| 6 | * This file contains the interface functions for the various |
| 7 | * time related system calls: time, stime, gettimeofday, settimeofday, |
| 8 | * adjtime |
| 9 | */ |
| 10 | /* |
| 11 | * Modification history kernel/time.c |
| 12 | * |
| 13 | * 1993-09-02 Philip Gladstone |
| 14 | * Created file with time related functions from sched.c and adjtimex() |
| 15 | * 1993-10-08 Torsten Duwe |
| 16 | * adjtime interface update and CMOS clock write code |
| 17 | * 1995-08-13 Torsten Duwe |
| 18 | * kernel PLL updated to 1994-12-13 specs (rfc-1589) |
| 19 | * 1999-01-16 Ulrich Windl |
| 20 | * Introduced error checking for many cases in adjtimex(). |
| 21 | * Updated NTP code according to technical memorandum Jan '96 |
| 22 | * "A Kernel Model for Precision Timekeeping" by Dave Mills |
| 23 | * Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10) |
| 24 | * (Even though the technical memorandum forbids it) |
| 25 | * 2004-07-14 Christoph Lameter |
| 26 | * Added getnstimeofday to allow the posix timer functions to return |
| 27 | * with nanosecond accuracy |
| 28 | */ |
| 29 | |
| 30 | #include <linux/module.h> |
| 31 | #include <linux/timex.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 32 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | #include <linux/errno.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | #include <linux/syscalls.h> |
| 35 | #include <linux/security.h> |
| 36 | #include <linux/fs.h> |
| 37 | #include <linux/module.h> |
| 38 | |
| 39 | #include <asm/uaccess.h> |
| 40 | #include <asm/unistd.h> |
| 41 | |
| 42 | /* |
| 43 | * The timezone where the local system is located. Used as a default by some |
| 44 | * programs who obtain this value by using gettimeofday. |
| 45 | */ |
| 46 | struct timezone sys_tz; |
| 47 | |
| 48 | EXPORT_SYMBOL(sys_tz); |
| 49 | |
| 50 | #ifdef __ARCH_WANT_SYS_TIME |
| 51 | |
| 52 | /* |
| 53 | * sys_time() can be implemented in user-level using |
| 54 | * sys_gettimeofday(). Is this for backwards compatibility? If so, |
| 55 | * why not move it into the appropriate arch directory (for those |
| 56 | * architectures that need it). |
| 57 | */ |
| 58 | asmlinkage long sys_time(time_t __user * tloc) |
| 59 | { |
Ingo Molnar | 4e44f34 | 2007-07-15 23:41:18 -0700 | [diff] [blame] | 60 | /* |
| 61 | * We read xtime.tv_sec atomically - it's updated |
| 62 | * atomically by update_wall_time(), so no need to |
| 63 | * even read-lock the xtime seqlock: |
| 64 | */ |
| 65 | time_t i = xtime.tv_sec; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | |
Ingo Molnar | 4e44f34 | 2007-07-15 23:41:18 -0700 | [diff] [blame] | 67 | smp_rmb(); /* sys_time() results are coherent */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | |
| 69 | if (tloc) { |
Ingo Molnar | 4e44f34 | 2007-07-15 23:41:18 -0700 | [diff] [blame] | 70 | if (put_user(i, tloc)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | i = -EFAULT; |
| 72 | } |
| 73 | return i; |
| 74 | } |
| 75 | |
| 76 | /* |
| 77 | * sys_stime() can be implemented in user-level using |
| 78 | * sys_settimeofday(). Is this for backwards compatibility? If so, |
| 79 | * why not move it into the appropriate arch directory (for those |
| 80 | * architectures that need it). |
| 81 | */ |
| 82 | |
| 83 | asmlinkage long sys_stime(time_t __user *tptr) |
| 84 | { |
| 85 | struct timespec tv; |
| 86 | int err; |
| 87 | |
| 88 | if (get_user(tv.tv_sec, tptr)) |
| 89 | return -EFAULT; |
| 90 | |
| 91 | tv.tv_nsec = 0; |
| 92 | |
| 93 | err = security_settime(&tv, NULL); |
| 94 | if (err) |
| 95 | return err; |
| 96 | |
| 97 | do_settimeofday(&tv); |
| 98 | return 0; |
| 99 | } |
| 100 | |
| 101 | #endif /* __ARCH_WANT_SYS_TIME */ |
| 102 | |
| 103 | asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz) |
| 104 | { |
| 105 | if (likely(tv != NULL)) { |
| 106 | struct timeval ktv; |
| 107 | do_gettimeofday(&ktv); |
| 108 | if (copy_to_user(tv, &ktv, sizeof(ktv))) |
| 109 | return -EFAULT; |
| 110 | } |
| 111 | if (unlikely(tz != NULL)) { |
| 112 | if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) |
| 113 | return -EFAULT; |
| 114 | } |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | /* |
| 119 | * Adjust the time obtained from the CMOS to be UTC time instead of |
| 120 | * local time. |
| 121 | * |
| 122 | * This is ugly, but preferable to the alternatives. Otherwise we |
| 123 | * would either need to write a program to do it in /etc/rc (and risk |
| 124 | * confusion if the program gets run more than once; it would also be |
| 125 | * hard to make the program warp the clock precisely n hours) or |
| 126 | * compile in the timezone information into the kernel. Bad, bad.... |
| 127 | * |
| 128 | * - TYT, 1992-01-01 |
| 129 | * |
| 130 | * The best thing to do is to keep the CMOS clock in universal time (UTC) |
| 131 | * as real UNIX machines always do it. This avoids all headaches about |
| 132 | * daylight saving times and warping kernel clocks. |
| 133 | */ |
Jesper Juhl | 77933d7 | 2005-07-27 11:46:09 -0700 | [diff] [blame] | 134 | static inline void warp_clock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | { |
| 136 | write_seqlock_irq(&xtime_lock); |
| 137 | wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60; |
| 138 | xtime.tv_sec += sys_tz.tz_minuteswest * 60; |
| 139 | time_interpolator_reset(); |
| 140 | write_sequnlock_irq(&xtime_lock); |
| 141 | clock_was_set(); |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * In case for some reason the CMOS clock has not already been running |
| 146 | * in UTC, but in some local time: The first time we set the timezone, |
| 147 | * we will warp the clock so that it is ticking UTC time instead of |
| 148 | * local time. Presumably, if someone is setting the timezone then we |
| 149 | * are running in an environment where the programs understand about |
| 150 | * timezones. This should be done at boot time in the /etc/rc script, |
| 151 | * as soon as possible, so that the clock can be set right. Otherwise, |
| 152 | * various programs will get confused when the clock gets warped. |
| 153 | */ |
| 154 | |
| 155 | int do_sys_settimeofday(struct timespec *tv, struct timezone *tz) |
| 156 | { |
| 157 | static int firsttime = 1; |
| 158 | int error = 0; |
| 159 | |
Linus Torvalds | 951069e | 2006-01-31 10:16:55 -0800 | [diff] [blame] | 160 | if (tv && !timespec_valid(tv)) |
Thomas Gleixner | 718bcce | 2006-01-09 20:52:29 -0800 | [diff] [blame] | 161 | return -EINVAL; |
| 162 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | error = security_settime(tv, tz); |
| 164 | if (error) |
| 165 | return error; |
| 166 | |
| 167 | if (tz) { |
| 168 | /* SMP safe, global irq locking makes it work. */ |
| 169 | sys_tz = *tz; |
| 170 | if (firsttime) { |
| 171 | firsttime = 0; |
| 172 | if (!tv) |
| 173 | warp_clock(); |
| 174 | } |
| 175 | } |
| 176 | if (tv) |
| 177 | { |
| 178 | /* SMP safe, again the code in arch/foo/time.c should |
| 179 | * globally block out interrupts when it runs. |
| 180 | */ |
| 181 | return do_settimeofday(tv); |
| 182 | } |
| 183 | return 0; |
| 184 | } |
| 185 | |
| 186 | asmlinkage long sys_settimeofday(struct timeval __user *tv, |
| 187 | struct timezone __user *tz) |
| 188 | { |
| 189 | struct timeval user_tv; |
| 190 | struct timespec new_ts; |
| 191 | struct timezone new_tz; |
| 192 | |
| 193 | if (tv) { |
| 194 | if (copy_from_user(&user_tv, tv, sizeof(*tv))) |
| 195 | return -EFAULT; |
| 196 | new_ts.tv_sec = user_tv.tv_sec; |
| 197 | new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; |
| 198 | } |
| 199 | if (tz) { |
| 200 | if (copy_from_user(&new_tz, tz, sizeof(*tz))) |
| 201 | return -EFAULT; |
| 202 | } |
| 203 | |
| 204 | return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL); |
| 205 | } |
| 206 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | asmlinkage long sys_adjtimex(struct timex __user *txc_p) |
| 208 | { |
| 209 | struct timex txc; /* Local copy of parameter */ |
| 210 | int ret; |
| 211 | |
| 212 | /* Copy the user data space into the kernel copy |
| 213 | * structure. But bear in mind that the structures |
| 214 | * may change |
| 215 | */ |
| 216 | if(copy_from_user(&txc, txc_p, sizeof(struct timex))) |
| 217 | return -EFAULT; |
| 218 | ret = do_adjtimex(&txc); |
| 219 | return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret; |
| 220 | } |
| 221 | |
| 222 | inline struct timespec current_kernel_time(void) |
| 223 | { |
| 224 | struct timespec now; |
| 225 | unsigned long seq; |
| 226 | |
| 227 | do { |
| 228 | seq = read_seqbegin(&xtime_lock); |
| 229 | |
| 230 | now = xtime; |
| 231 | } while (read_seqretry(&xtime_lock, seq)); |
| 232 | |
| 233 | return now; |
| 234 | } |
| 235 | |
| 236 | EXPORT_SYMBOL(current_kernel_time); |
| 237 | |
| 238 | /** |
| 239 | * current_fs_time - Return FS time |
| 240 | * @sb: Superblock. |
| 241 | * |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 242 | * Return the current time truncated to the time granularity supported by |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | * the fs. |
| 244 | */ |
| 245 | struct timespec current_fs_time(struct super_block *sb) |
| 246 | { |
| 247 | struct timespec now = current_kernel_time(); |
| 248 | return timespec_trunc(now, sb->s_time_gran); |
| 249 | } |
| 250 | EXPORT_SYMBOL(current_fs_time); |
| 251 | |
Eric Dumazet | 753e9c5 | 2007-05-08 00:25:32 -0700 | [diff] [blame] | 252 | /* |
| 253 | * Convert jiffies to milliseconds and back. |
| 254 | * |
| 255 | * Avoid unnecessary multiplications/divisions in the |
| 256 | * two most common HZ cases: |
| 257 | */ |
| 258 | unsigned int inline jiffies_to_msecs(const unsigned long j) |
| 259 | { |
| 260 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
| 261 | return (MSEC_PER_SEC / HZ) * j; |
| 262 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
| 263 | return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); |
| 264 | #else |
| 265 | return (j * MSEC_PER_SEC) / HZ; |
| 266 | #endif |
| 267 | } |
| 268 | EXPORT_SYMBOL(jiffies_to_msecs); |
| 269 | |
| 270 | unsigned int inline jiffies_to_usecs(const unsigned long j) |
| 271 | { |
| 272 | #if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ) |
| 273 | return (USEC_PER_SEC / HZ) * j; |
| 274 | #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) |
| 275 | return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC); |
| 276 | #else |
| 277 | return (j * USEC_PER_SEC) / HZ; |
| 278 | #endif |
| 279 | } |
| 280 | EXPORT_SYMBOL(jiffies_to_usecs); |
| 281 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | /** |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 283 | * timespec_trunc - Truncate timespec to a granularity |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | * @t: Timespec |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 285 | * @gran: Granularity in ns. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | * |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 287 | * Truncate a timespec to a granularity. gran must be smaller than a second. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | * Always rounds down. |
| 289 | * |
| 290 | * This function should be only used for timestamps returned by |
| 291 | * current_kernel_time() or CURRENT_TIME, not with do_gettimeofday() because |
| 292 | * it doesn't handle the better resolution of the later. |
| 293 | */ |
| 294 | struct timespec timespec_trunc(struct timespec t, unsigned gran) |
| 295 | { |
| 296 | /* |
| 297 | * Division is pretty slow so avoid it for common cases. |
| 298 | * Currently current_kernel_time() never returns better than |
| 299 | * jiffies resolution. Exploit that. |
| 300 | */ |
| 301 | if (gran <= jiffies_to_usecs(1) * 1000) { |
| 302 | /* nothing */ |
| 303 | } else if (gran == 1000000000) { |
| 304 | t.tv_nsec = 0; |
| 305 | } else { |
| 306 | t.tv_nsec -= t.tv_nsec % gran; |
| 307 | } |
| 308 | return t; |
| 309 | } |
| 310 | EXPORT_SYMBOL(timespec_trunc); |
| 311 | |
| 312 | #ifdef CONFIG_TIME_INTERPOLATION |
| 313 | void getnstimeofday (struct timespec *tv) |
| 314 | { |
| 315 | unsigned long seq,sec,nsec; |
| 316 | |
| 317 | do { |
| 318 | seq = read_seqbegin(&xtime_lock); |
| 319 | sec = xtime.tv_sec; |
| 320 | nsec = xtime.tv_nsec+time_interpolator_get_offset(); |
| 321 | } while (unlikely(read_seqretry(&xtime_lock, seq))); |
| 322 | |
| 323 | while (unlikely(nsec >= NSEC_PER_SEC)) { |
| 324 | nsec -= NSEC_PER_SEC; |
| 325 | ++sec; |
| 326 | } |
| 327 | tv->tv_sec = sec; |
| 328 | tv->tv_nsec = nsec; |
| 329 | } |
| 330 | EXPORT_SYMBOL_GPL(getnstimeofday); |
| 331 | |
| 332 | int do_settimeofday (struct timespec *tv) |
| 333 | { |
| 334 | time_t wtm_sec, sec = tv->tv_sec; |
| 335 | long wtm_nsec, nsec = tv->tv_nsec; |
| 336 | |
| 337 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 338 | return -EINVAL; |
| 339 | |
| 340 | write_seqlock_irq(&xtime_lock); |
| 341 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); |
| 343 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); |
| 344 | |
| 345 | set_normalized_timespec(&xtime, sec, nsec); |
| 346 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); |
| 347 | |
| 348 | time_adjust = 0; /* stop active adjtime() */ |
| 349 | time_status |= STA_UNSYNC; |
| 350 | time_maxerror = NTP_PHASE_LIMIT; |
| 351 | time_esterror = NTP_PHASE_LIMIT; |
| 352 | time_interpolator_reset(); |
| 353 | } |
| 354 | write_sequnlock_irq(&xtime_lock); |
| 355 | clock_was_set(); |
| 356 | return 0; |
| 357 | } |
Al Viro | 943eae0 | 2005-10-29 07:32:07 +0100 | [diff] [blame] | 358 | EXPORT_SYMBOL(do_settimeofday); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | |
| 360 | void do_gettimeofday (struct timeval *tv) |
| 361 | { |
| 362 | unsigned long seq, nsec, usec, sec, offset; |
| 363 | do { |
| 364 | seq = read_seqbegin(&xtime_lock); |
| 365 | offset = time_interpolator_get_offset(); |
| 366 | sec = xtime.tv_sec; |
| 367 | nsec = xtime.tv_nsec; |
| 368 | } while (unlikely(read_seqretry(&xtime_lock, seq))); |
| 369 | |
| 370 | usec = (nsec + offset) / 1000; |
| 371 | |
| 372 | while (unlikely(usec >= USEC_PER_SEC)) { |
| 373 | usec -= USEC_PER_SEC; |
| 374 | ++sec; |
| 375 | } |
| 376 | |
| 377 | tv->tv_sec = sec; |
| 378 | tv->tv_usec = usec; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | |
Ingo Molnar | 4e44f34 | 2007-07-15 23:41:18 -0700 | [diff] [blame] | 380 | /* |
| 381 | * Make sure xtime.tv_sec [returned by sys_time()] always |
| 382 | * follows the gettimeofday() result precisely. This |
| 383 | * condition is extremely unlikely, it can hit at most |
| 384 | * once per second: |
| 385 | */ |
| 386 | if (unlikely(xtime.tv_sec != tv->tv_sec)) { |
| 387 | unsigned long flags; |
| 388 | |
| 389 | write_seqlock_irqsave(&xtime_lock, flags); |
| 390 | update_wall_time(); |
| 391 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 392 | } |
| 393 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | EXPORT_SYMBOL(do_gettimeofday); |
| 395 | |
Ingo Molnar | 4e44f34 | 2007-07-15 23:41:18 -0700 | [diff] [blame] | 396 | #else /* CONFIG_TIME_INTERPOLATION */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 397 | |
john stultz | cf3c769 | 2006-06-26 00:25:08 -0700 | [diff] [blame] | 398 | #ifndef CONFIG_GENERIC_TIME |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | /* |
| 400 | * Simulate gettimeofday using do_gettimeofday which only allows a timeval |
| 401 | * and therefore only yields usec accuracy |
| 402 | */ |
| 403 | void getnstimeofday(struct timespec *tv) |
| 404 | { |
| 405 | struct timeval x; |
| 406 | |
| 407 | do_gettimeofday(&x); |
| 408 | tv->tv_sec = x.tv_sec; |
| 409 | tv->tv_nsec = x.tv_usec * NSEC_PER_USEC; |
| 410 | } |
Takashi Iwai | c6ecf7e | 2005-10-14 15:59:03 -0700 | [diff] [blame] | 411 | EXPORT_SYMBOL_GPL(getnstimeofday); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | #endif |
Ingo Molnar | 4e44f34 | 2007-07-15 23:41:18 -0700 | [diff] [blame] | 413 | #endif /* CONFIG_TIME_INTERPOLATION */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 415 | /* Converts Gregorian date to seconds since 1970-01-01 00:00:00. |
| 416 | * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 |
| 417 | * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. |
| 418 | * |
| 419 | * [For the Julian calendar (which was used in Russia before 1917, |
| 420 | * Britain & colonies before 1752, anywhere else before 1582, |
| 421 | * and is still in use by some communities) leave out the |
| 422 | * -year/100+year/400 terms, and add 10.] |
| 423 | * |
| 424 | * This algorithm was first published by Gauss (I think). |
| 425 | * |
| 426 | * WARNING: this function will overflow on 2106-02-07 06:28:16 on |
| 427 | * machines were long is 32-bit! (However, as time_t is signed, we |
| 428 | * will already get problems at other places on 2038-01-19 03:14:08) |
| 429 | */ |
| 430 | unsigned long |
Ingo Molnar | f481890 | 2006-01-09 20:52:23 -0800 | [diff] [blame] | 431 | mktime(const unsigned int year0, const unsigned int mon0, |
| 432 | const unsigned int day, const unsigned int hour, |
| 433 | const unsigned int min, const unsigned int sec) |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 434 | { |
Ingo Molnar | f481890 | 2006-01-09 20:52:23 -0800 | [diff] [blame] | 435 | unsigned int mon = mon0, year = year0; |
| 436 | |
| 437 | /* 1..12 -> 11,12,1..10 */ |
| 438 | if (0 >= (int) (mon -= 2)) { |
| 439 | mon += 12; /* Puts Feb last since it has leap day */ |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 440 | year -= 1; |
| 441 | } |
| 442 | |
| 443 | return ((((unsigned long) |
| 444 | (year/4 - year/100 + year/400 + 367*mon/12 + day) + |
| 445 | year*365 - 719499 |
| 446 | )*24 + hour /* now have hours */ |
| 447 | )*60 + min /* now have minutes */ |
| 448 | )*60 + sec; /* finally seconds */ |
| 449 | } |
| 450 | |
Andrew Morton | 199e705 | 2006-01-09 20:52:24 -0800 | [diff] [blame] | 451 | EXPORT_SYMBOL(mktime); |
| 452 | |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 453 | /** |
| 454 | * set_normalized_timespec - set timespec sec and nsec parts and normalize |
| 455 | * |
| 456 | * @ts: pointer to timespec variable to be set |
| 457 | * @sec: seconds to set |
| 458 | * @nsec: nanoseconds to set |
| 459 | * |
| 460 | * Set seconds and nanoseconds field of a timespec variable and |
| 461 | * normalize to the timespec storage format |
| 462 | * |
| 463 | * Note: The tv_nsec part is always in the range of |
| 464 | * 0 <= tv_nsec < NSEC_PER_SEC |
| 465 | * For negative values only the tv_sec field is negative ! |
| 466 | */ |
Ingo Molnar | f481890 | 2006-01-09 20:52:23 -0800 | [diff] [blame] | 467 | void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec) |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 468 | { |
| 469 | while (nsec >= NSEC_PER_SEC) { |
| 470 | nsec -= NSEC_PER_SEC; |
| 471 | ++sec; |
| 472 | } |
| 473 | while (nsec < 0) { |
| 474 | nsec += NSEC_PER_SEC; |
| 475 | --sec; |
| 476 | } |
| 477 | ts->tv_sec = sec; |
| 478 | ts->tv_nsec = nsec; |
| 479 | } |
| 480 | |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 481 | /** |
| 482 | * ns_to_timespec - Convert nanoseconds to timespec |
| 483 | * @nsec: the nanoseconds value to be converted |
| 484 | * |
| 485 | * Returns the timespec representation of the nsec parameter. |
| 486 | */ |
Roman Zippel | df869b6 | 2006-03-26 01:38:11 -0800 | [diff] [blame] | 487 | struct timespec ns_to_timespec(const s64 nsec) |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 488 | { |
| 489 | struct timespec ts; |
| 490 | |
George Anzinger | 88fc389 | 2006-02-03 03:04:20 -0800 | [diff] [blame] | 491 | if (!nsec) |
| 492 | return (struct timespec) {0, 0}; |
| 493 | |
| 494 | ts.tv_sec = div_long_long_rem_signed(nsec, NSEC_PER_SEC, &ts.tv_nsec); |
| 495 | if (unlikely(nsec < 0)) |
| 496 | set_normalized_timespec(&ts, ts.tv_sec, ts.tv_nsec); |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 497 | |
| 498 | return ts; |
| 499 | } |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 500 | EXPORT_SYMBOL(ns_to_timespec); |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 501 | |
| 502 | /** |
| 503 | * ns_to_timeval - Convert nanoseconds to timeval |
| 504 | * @nsec: the nanoseconds value to be converted |
| 505 | * |
| 506 | * Returns the timeval representation of the nsec parameter. |
| 507 | */ |
Roman Zippel | df869b6 | 2006-03-26 01:38:11 -0800 | [diff] [blame] | 508 | struct timeval ns_to_timeval(const s64 nsec) |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 509 | { |
| 510 | struct timespec ts = ns_to_timespec(nsec); |
| 511 | struct timeval tv; |
| 512 | |
| 513 | tv.tv_sec = ts.tv_sec; |
| 514 | tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000; |
| 515 | |
| 516 | return tv; |
| 517 | } |
Eric Dumazet | b7aa0bf | 2007-04-19 16:16:32 -0700 | [diff] [blame] | 518 | EXPORT_SYMBOL(ns_to_timeval); |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 519 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 520 | /* |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 521 | * When we convert to jiffies then we interpret incoming values |
| 522 | * the following way: |
| 523 | * |
| 524 | * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) |
| 525 | * |
| 526 | * - 'too large' values [that would result in larger than |
| 527 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
| 528 | * |
| 529 | * - all other values are converted to jiffies by either multiplying |
| 530 | * the input value by a factor or dividing it with a factor |
| 531 | * |
| 532 | * We must also be careful about 32-bit overflows. |
| 533 | */ |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 534 | unsigned long msecs_to_jiffies(const unsigned int m) |
| 535 | { |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 536 | /* |
| 537 | * Negative value, means infinite timeout: |
| 538 | */ |
| 539 | if ((int)m < 0) |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 540 | return MAX_JIFFY_OFFSET; |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 541 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 542 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 543 | /* |
| 544 | * HZ is equal to or smaller than 1000, and 1000 is a nice |
| 545 | * round multiple of HZ, divide with the factor between them, |
| 546 | * but round upwards: |
| 547 | */ |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 548 | return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ); |
| 549 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 550 | /* |
| 551 | * HZ is larger than 1000, and HZ is a nice round multiple of |
| 552 | * 1000 - simply multiply with the factor between them. |
| 553 | * |
| 554 | * But first make sure the multiplication result cannot |
| 555 | * overflow: |
| 556 | */ |
| 557 | if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| 558 | return MAX_JIFFY_OFFSET; |
| 559 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 560 | return m * (HZ / MSEC_PER_SEC); |
| 561 | #else |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 562 | /* |
| 563 | * Generic case - multiply, round and divide. But first |
| 564 | * check that if we are doing a net multiplication, that |
| 565 | * we wouldnt overflow: |
| 566 | */ |
| 567 | if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| 568 | return MAX_JIFFY_OFFSET; |
| 569 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 570 | return (m * HZ + MSEC_PER_SEC - 1) / MSEC_PER_SEC; |
| 571 | #endif |
| 572 | } |
| 573 | EXPORT_SYMBOL(msecs_to_jiffies); |
| 574 | |
| 575 | unsigned long usecs_to_jiffies(const unsigned int u) |
| 576 | { |
| 577 | if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) |
| 578 | return MAX_JIFFY_OFFSET; |
| 579 | #if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ) |
| 580 | return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ); |
| 581 | #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) |
| 582 | return u * (HZ / USEC_PER_SEC); |
| 583 | #else |
| 584 | return (u * HZ + USEC_PER_SEC - 1) / USEC_PER_SEC; |
| 585 | #endif |
| 586 | } |
| 587 | EXPORT_SYMBOL(usecs_to_jiffies); |
| 588 | |
| 589 | /* |
| 590 | * The TICK_NSEC - 1 rounds up the value to the next resolution. Note |
| 591 | * that a remainder subtract here would not do the right thing as the |
| 592 | * resolution values don't fall on second boundries. I.e. the line: |
| 593 | * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. |
| 594 | * |
| 595 | * Rather, we just shift the bits off the right. |
| 596 | * |
| 597 | * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec |
| 598 | * value to a scaled second value. |
| 599 | */ |
| 600 | unsigned long |
| 601 | timespec_to_jiffies(const struct timespec *value) |
| 602 | { |
| 603 | unsigned long sec = value->tv_sec; |
| 604 | long nsec = value->tv_nsec + TICK_NSEC - 1; |
| 605 | |
| 606 | if (sec >= MAX_SEC_IN_JIFFIES){ |
| 607 | sec = MAX_SEC_IN_JIFFIES; |
| 608 | nsec = 0; |
| 609 | } |
| 610 | return (((u64)sec * SEC_CONVERSION) + |
| 611 | (((u64)nsec * NSEC_CONVERSION) >> |
| 612 | (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; |
| 613 | |
| 614 | } |
| 615 | EXPORT_SYMBOL(timespec_to_jiffies); |
| 616 | |
| 617 | void |
| 618 | jiffies_to_timespec(const unsigned long jiffies, struct timespec *value) |
| 619 | { |
| 620 | /* |
| 621 | * Convert jiffies to nanoseconds and separate with |
| 622 | * one divide. |
| 623 | */ |
| 624 | u64 nsec = (u64)jiffies * TICK_NSEC; |
| 625 | value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_nsec); |
| 626 | } |
| 627 | EXPORT_SYMBOL(jiffies_to_timespec); |
| 628 | |
| 629 | /* Same for "timeval" |
| 630 | * |
| 631 | * Well, almost. The problem here is that the real system resolution is |
| 632 | * in nanoseconds and the value being converted is in micro seconds. |
| 633 | * Also for some machines (those that use HZ = 1024, in-particular), |
| 634 | * there is a LARGE error in the tick size in microseconds. |
| 635 | |
| 636 | * The solution we use is to do the rounding AFTER we convert the |
| 637 | * microsecond part. Thus the USEC_ROUND, the bits to be shifted off. |
| 638 | * Instruction wise, this should cost only an additional add with carry |
| 639 | * instruction above the way it was done above. |
| 640 | */ |
| 641 | unsigned long |
| 642 | timeval_to_jiffies(const struct timeval *value) |
| 643 | { |
| 644 | unsigned long sec = value->tv_sec; |
| 645 | long usec = value->tv_usec; |
| 646 | |
| 647 | if (sec >= MAX_SEC_IN_JIFFIES){ |
| 648 | sec = MAX_SEC_IN_JIFFIES; |
| 649 | usec = 0; |
| 650 | } |
| 651 | return (((u64)sec * SEC_CONVERSION) + |
| 652 | (((u64)usec * USEC_CONVERSION + USEC_ROUND) >> |
| 653 | (USEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; |
| 654 | } |
Thomas Bittermann | 456a09d | 2007-04-04 22:20:54 +0200 | [diff] [blame] | 655 | EXPORT_SYMBOL(timeval_to_jiffies); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 656 | |
| 657 | void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value) |
| 658 | { |
| 659 | /* |
| 660 | * Convert jiffies to nanoseconds and separate with |
| 661 | * one divide. |
| 662 | */ |
| 663 | u64 nsec = (u64)jiffies * TICK_NSEC; |
| 664 | long tv_usec; |
| 665 | |
| 666 | value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tv_usec); |
| 667 | tv_usec /= NSEC_PER_USEC; |
| 668 | value->tv_usec = tv_usec; |
| 669 | } |
Thomas Bittermann | 456a09d | 2007-04-04 22:20:54 +0200 | [diff] [blame] | 670 | EXPORT_SYMBOL(jiffies_to_timeval); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 671 | |
| 672 | /* |
| 673 | * Convert jiffies/jiffies_64 to clock_t and back. |
| 674 | */ |
| 675 | clock_t jiffies_to_clock_t(long x) |
| 676 | { |
| 677 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 |
| 678 | return x / (HZ / USER_HZ); |
| 679 | #else |
| 680 | u64 tmp = (u64)x * TICK_NSEC; |
| 681 | do_div(tmp, (NSEC_PER_SEC / USER_HZ)); |
| 682 | return (long)tmp; |
| 683 | #endif |
| 684 | } |
| 685 | EXPORT_SYMBOL(jiffies_to_clock_t); |
| 686 | |
| 687 | unsigned long clock_t_to_jiffies(unsigned long x) |
| 688 | { |
| 689 | #if (HZ % USER_HZ)==0 |
| 690 | if (x >= ~0UL / (HZ / USER_HZ)) |
| 691 | return ~0UL; |
| 692 | return x * (HZ / USER_HZ); |
| 693 | #else |
| 694 | u64 jif; |
| 695 | |
| 696 | /* Don't worry about loss of precision here .. */ |
| 697 | if (x >= ~0UL / HZ * USER_HZ) |
| 698 | return ~0UL; |
| 699 | |
| 700 | /* .. but do try to contain it here */ |
| 701 | jif = x * (u64) HZ; |
| 702 | do_div(jif, USER_HZ); |
| 703 | return jif; |
| 704 | #endif |
| 705 | } |
| 706 | EXPORT_SYMBOL(clock_t_to_jiffies); |
| 707 | |
| 708 | u64 jiffies_64_to_clock_t(u64 x) |
| 709 | { |
| 710 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 |
| 711 | do_div(x, HZ / USER_HZ); |
| 712 | #else |
| 713 | /* |
| 714 | * There are better ways that don't overflow early, |
| 715 | * but even this doesn't overflow in hundreds of years |
| 716 | * in 64 bits, so.. |
| 717 | */ |
| 718 | x *= TICK_NSEC; |
| 719 | do_div(x, (NSEC_PER_SEC / USER_HZ)); |
| 720 | #endif |
| 721 | return x; |
| 722 | } |
| 723 | |
| 724 | EXPORT_SYMBOL(jiffies_64_to_clock_t); |
| 725 | |
| 726 | u64 nsec_to_clock_t(u64 x) |
| 727 | { |
| 728 | #if (NSEC_PER_SEC % USER_HZ) == 0 |
| 729 | do_div(x, (NSEC_PER_SEC / USER_HZ)); |
| 730 | #elif (USER_HZ % 512) == 0 |
| 731 | x *= USER_HZ/512; |
| 732 | do_div(x, (NSEC_PER_SEC / 512)); |
| 733 | #else |
| 734 | /* |
| 735 | * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, |
| 736 | * overflow after 64.99 years. |
| 737 | * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... |
| 738 | */ |
| 739 | x *= 9; |
| 740 | do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2)) / |
| 741 | USER_HZ)); |
| 742 | #endif |
| 743 | return x; |
| 744 | } |
| 745 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | #if (BITS_PER_LONG < 64) |
| 747 | u64 get_jiffies_64(void) |
| 748 | { |
| 749 | unsigned long seq; |
| 750 | u64 ret; |
| 751 | |
| 752 | do { |
| 753 | seq = read_seqbegin(&xtime_lock); |
| 754 | ret = jiffies_64; |
| 755 | } while (read_seqretry(&xtime_lock, seq)); |
| 756 | return ret; |
| 757 | } |
| 758 | |
| 759 | EXPORT_SYMBOL(get_jiffies_64); |
| 760 | #endif |
| 761 | |
| 762 | EXPORT_SYMBOL(jiffies); |