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 |
Daniel Walker | 6fa6c3b | 2007-10-18 03:06:03 -0700 | [diff] [blame] | 12 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | * 1993-09-02 Philip Gladstone |
Daniel Walker | 6fa6c3b | 2007-10-18 03:06:03 -0700 | [diff] [blame] | 14 | * Created file with time related functions from sched.c and adjtimex() |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Tony Breeds | 2c62214 | 2007-10-18 03:04:57 -0700 | [diff] [blame] | 33 | #include <linux/clocksource.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | #include <linux/errno.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/syscalls.h> |
| 36 | #include <linux/security.h> |
| 37 | #include <linux/fs.h> |
Robert P. J. Day | 1aeb272 | 2008-04-29 00:59:25 -0700 | [diff] [blame] | 38 | #include <linux/slab.h> |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 39 | #include <linux/math64.h> |
Paul Mackerras | e3d5a27 | 2009-01-06 14:41:02 -0800 | [diff] [blame] | 40 | #include <linux/ptrace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | |
| 42 | #include <asm/uaccess.h> |
| 43 | #include <asm/unistd.h> |
| 44 | |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 45 | #include "timeconst.h" |
| 46 | |
Daniel Walker | 6fa6c3b | 2007-10-18 03:06:03 -0700 | [diff] [blame] | 47 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | * The timezone where the local system is located. Used as a default by some |
| 49 | * programs who obtain this value by using gettimeofday. |
| 50 | */ |
| 51 | struct timezone sys_tz; |
| 52 | |
| 53 | EXPORT_SYMBOL(sys_tz); |
| 54 | |
| 55 | #ifdef __ARCH_WANT_SYS_TIME |
| 56 | |
| 57 | /* |
| 58 | * sys_time() can be implemented in user-level using |
| 59 | * sys_gettimeofday(). Is this for backwards compatibility? If so, |
| 60 | * why not move it into the appropriate arch directory (for those |
| 61 | * architectures that need it). |
| 62 | */ |
Heiko Carstens | 58fd3aa | 2009-01-14 14:14:03 +0100 | [diff] [blame] | 63 | SYSCALL_DEFINE1(time, time_t __user *, tloc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | { |
Ingo Molnar | f20bf61 | 2007-10-16 16:09:20 +0200 | [diff] [blame] | 65 | time_t i = get_seconds(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | |
| 67 | if (tloc) { |
Linus Torvalds | 2008220 | 2007-07-20 13:28:54 -0700 | [diff] [blame] | 68 | if (put_user(i,tloc)) |
Paul Mackerras | e3d5a27 | 2009-01-06 14:41:02 -0800 | [diff] [blame] | 69 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | } |
Paul Mackerras | e3d5a27 | 2009-01-06 14:41:02 -0800 | [diff] [blame] | 71 | force_successful_syscall_return(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | return i; |
| 73 | } |
| 74 | |
| 75 | /* |
| 76 | * sys_stime() can be implemented in user-level using |
| 77 | * sys_settimeofday(). Is this for backwards compatibility? If so, |
| 78 | * why not move it into the appropriate arch directory (for those |
| 79 | * architectures that need it). |
| 80 | */ |
Daniel Walker | 6fa6c3b | 2007-10-18 03:06:03 -0700 | [diff] [blame] | 81 | |
Heiko Carstens | 58fd3aa | 2009-01-14 14:14:03 +0100 | [diff] [blame] | 82 | SYSCALL_DEFINE1(stime, time_t __user *, tptr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | { |
| 84 | struct timespec tv; |
| 85 | int err; |
| 86 | |
| 87 | if (get_user(tv.tv_sec, tptr)) |
| 88 | return -EFAULT; |
| 89 | |
| 90 | tv.tv_nsec = 0; |
| 91 | |
| 92 | err = security_settime(&tv, NULL); |
| 93 | if (err) |
| 94 | return err; |
| 95 | |
| 96 | do_settimeofday(&tv); |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | #endif /* __ARCH_WANT_SYS_TIME */ |
| 101 | |
Heiko Carstens | 58fd3aa | 2009-01-14 14:14:03 +0100 | [diff] [blame] | 102 | SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv, |
| 103 | struct timezone __user *, tz) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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. |
Daniel Walker | 6fa6c3b | 2007-10-18 03:06:03 -0700 | [diff] [blame] | 121 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Daniel Walker | 6fa6c3b | 2007-10-18 03:06:03 -0700 | [diff] [blame] | 124 | * confusion if the program gets run more than once; it would also be |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | * |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 128 | * - TYT, 1992-01-01 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Thomas Gleixner | 1001d0a | 2008-02-01 17:45:13 +0100 | [diff] [blame] | 139 | update_xtime_cache(0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Tony Breeds | 2c62214 | 2007-10-18 03:04:57 -0700 | [diff] [blame] | 170 | update_vsyscall_tz(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | if (firsttime) { |
| 172 | firsttime = 0; |
| 173 | if (!tv) |
| 174 | warp_clock(); |
| 175 | } |
| 176 | } |
| 177 | if (tv) |
| 178 | { |
| 179 | /* SMP safe, again the code in arch/foo/time.c should |
| 180 | * globally block out interrupts when it runs. |
| 181 | */ |
| 182 | return do_settimeofday(tv); |
| 183 | } |
| 184 | return 0; |
| 185 | } |
| 186 | |
Heiko Carstens | 58fd3aa | 2009-01-14 14:14:03 +0100 | [diff] [blame] | 187 | SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, |
| 188 | struct timezone __user *, tz) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | { |
| 190 | struct timeval user_tv; |
| 191 | struct timespec new_ts; |
| 192 | struct timezone new_tz; |
| 193 | |
| 194 | if (tv) { |
| 195 | if (copy_from_user(&user_tv, tv, sizeof(*tv))) |
| 196 | return -EFAULT; |
| 197 | new_ts.tv_sec = user_tv.tv_sec; |
| 198 | new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; |
| 199 | } |
| 200 | if (tz) { |
| 201 | if (copy_from_user(&new_tz, tz, sizeof(*tz))) |
| 202 | return -EFAULT; |
| 203 | } |
| 204 | |
| 205 | return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL); |
| 206 | } |
| 207 | |
Heiko Carstens | 58fd3aa | 2009-01-14 14:14:03 +0100 | [diff] [blame] | 208 | SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | { |
| 210 | struct timex txc; /* Local copy of parameter */ |
| 211 | int ret; |
| 212 | |
| 213 | /* Copy the user data space into the kernel copy |
| 214 | * structure. But bear in mind that the structures |
| 215 | * may change |
| 216 | */ |
| 217 | if(copy_from_user(&txc, txc_p, sizeof(struct timex))) |
| 218 | return -EFAULT; |
| 219 | ret = do_adjtimex(&txc); |
| 220 | return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret; |
| 221 | } |
| 222 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | /** |
| 224 | * current_fs_time - Return FS time |
| 225 | * @sb: Superblock. |
| 226 | * |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 227 | * Return the current time truncated to the time granularity supported by |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | * the fs. |
| 229 | */ |
| 230 | struct timespec current_fs_time(struct super_block *sb) |
| 231 | { |
| 232 | struct timespec now = current_kernel_time(); |
| 233 | return timespec_trunc(now, sb->s_time_gran); |
| 234 | } |
| 235 | EXPORT_SYMBOL(current_fs_time); |
| 236 | |
Eric Dumazet | 753e9c5 | 2007-05-08 00:25:32 -0700 | [diff] [blame] | 237 | /* |
| 238 | * Convert jiffies to milliseconds and back. |
| 239 | * |
| 240 | * Avoid unnecessary multiplications/divisions in the |
| 241 | * two most common HZ cases: |
| 242 | */ |
| 243 | unsigned int inline jiffies_to_msecs(const unsigned long j) |
| 244 | { |
| 245 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
| 246 | return (MSEC_PER_SEC / HZ) * j; |
| 247 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
| 248 | return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); |
| 249 | #else |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 250 | # if BITS_PER_LONG == 32 |
H. Peter Anvin | b9095fd | 2008-05-02 16:18:42 -0700 | [diff] [blame] | 251 | return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32; |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 252 | # else |
| 253 | return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN; |
| 254 | # endif |
Eric Dumazet | 753e9c5 | 2007-05-08 00:25:32 -0700 | [diff] [blame] | 255 | #endif |
| 256 | } |
| 257 | EXPORT_SYMBOL(jiffies_to_msecs); |
| 258 | |
| 259 | unsigned int inline jiffies_to_usecs(const unsigned long j) |
| 260 | { |
| 261 | #if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ) |
| 262 | return (USEC_PER_SEC / HZ) * j; |
| 263 | #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) |
| 264 | return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC); |
| 265 | #else |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 266 | # if BITS_PER_LONG == 32 |
H. Peter Anvin | b9095fd | 2008-05-02 16:18:42 -0700 | [diff] [blame] | 267 | return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32; |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 268 | # else |
| 269 | return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN; |
| 270 | # endif |
Eric Dumazet | 753e9c5 | 2007-05-08 00:25:32 -0700 | [diff] [blame] | 271 | #endif |
| 272 | } |
| 273 | EXPORT_SYMBOL(jiffies_to_usecs); |
| 274 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | /** |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 276 | * timespec_trunc - Truncate timespec to a granularity |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | * @t: Timespec |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 278 | * @gran: Granularity in ns. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | * |
Kalin KOZHUHAROV | 8ba8e95 | 2006-04-01 01:41:22 +0200 | [diff] [blame] | 280 | * 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] | 281 | * Always rounds down. |
| 282 | * |
| 283 | * This function should be only used for timestamps returned by |
| 284 | * current_kernel_time() or CURRENT_TIME, not with do_gettimeofday() because |
Li Zefan | 3eb0567 | 2008-02-08 04:19:25 -0800 | [diff] [blame] | 285 | * it doesn't handle the better resolution of the latter. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | */ |
| 287 | struct timespec timespec_trunc(struct timespec t, unsigned gran) |
| 288 | { |
| 289 | /* |
| 290 | * Division is pretty slow so avoid it for common cases. |
| 291 | * Currently current_kernel_time() never returns better than |
| 292 | * jiffies resolution. Exploit that. |
| 293 | */ |
| 294 | if (gran <= jiffies_to_usecs(1) * 1000) { |
| 295 | /* nothing */ |
| 296 | } else if (gran == 1000000000) { |
| 297 | t.tv_nsec = 0; |
| 298 | } else { |
| 299 | t.tv_nsec -= t.tv_nsec % gran; |
| 300 | } |
| 301 | return t; |
| 302 | } |
| 303 | EXPORT_SYMBOL(timespec_trunc); |
| 304 | |
john stultz | cf3c769 | 2006-06-26 00:25:08 -0700 | [diff] [blame] | 305 | #ifndef CONFIG_GENERIC_TIME |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | /* |
| 307 | * Simulate gettimeofday using do_gettimeofday which only allows a timeval |
| 308 | * and therefore only yields usec accuracy |
| 309 | */ |
| 310 | void getnstimeofday(struct timespec *tv) |
| 311 | { |
| 312 | struct timeval x; |
| 313 | |
| 314 | do_gettimeofday(&x); |
| 315 | tv->tv_sec = x.tv_sec; |
| 316 | tv->tv_nsec = x.tv_usec * NSEC_PER_USEC; |
| 317 | } |
Takashi Iwai | c6ecf7e | 2005-10-14 15:59:03 -0700 | [diff] [blame] | 318 | EXPORT_SYMBOL_GPL(getnstimeofday); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | #endif |
| 320 | |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 321 | /* Converts Gregorian date to seconds since 1970-01-01 00:00:00. |
| 322 | * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 |
| 323 | * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. |
| 324 | * |
| 325 | * [For the Julian calendar (which was used in Russia before 1917, |
| 326 | * Britain & colonies before 1752, anywhere else before 1582, |
| 327 | * and is still in use by some communities) leave out the |
| 328 | * -year/100+year/400 terms, and add 10.] |
| 329 | * |
| 330 | * This algorithm was first published by Gauss (I think). |
| 331 | * |
| 332 | * WARNING: this function will overflow on 2106-02-07 06:28:16 on |
Li Zefan | 3eb0567 | 2008-02-08 04:19:25 -0800 | [diff] [blame] | 333 | * machines where long is 32-bit! (However, as time_t is signed, we |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 334 | * will already get problems at other places on 2038-01-19 03:14:08) |
| 335 | */ |
| 336 | unsigned long |
Ingo Molnar | f481890 | 2006-01-09 20:52:23 -0800 | [diff] [blame] | 337 | mktime(const unsigned int year0, const unsigned int mon0, |
| 338 | const unsigned int day, const unsigned int hour, |
| 339 | const unsigned int min, const unsigned int sec) |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 340 | { |
Ingo Molnar | f481890 | 2006-01-09 20:52:23 -0800 | [diff] [blame] | 341 | unsigned int mon = mon0, year = year0; |
| 342 | |
| 343 | /* 1..12 -> 11,12,1..10 */ |
| 344 | if (0 >= (int) (mon -= 2)) { |
| 345 | mon += 12; /* Puts Feb last since it has leap day */ |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 346 | year -= 1; |
| 347 | } |
| 348 | |
| 349 | return ((((unsigned long) |
| 350 | (year/4 - year/100 + year/400 + 367*mon/12 + day) + |
| 351 | year*365 - 719499 |
| 352 | )*24 + hour /* now have hours */ |
| 353 | )*60 + min /* now have minutes */ |
| 354 | )*60 + sec; /* finally seconds */ |
| 355 | } |
| 356 | |
Andrew Morton | 199e705 | 2006-01-09 20:52:24 -0800 | [diff] [blame] | 357 | EXPORT_SYMBOL(mktime); |
| 358 | |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 359 | /** |
| 360 | * set_normalized_timespec - set timespec sec and nsec parts and normalize |
| 361 | * |
| 362 | * @ts: pointer to timespec variable to be set |
| 363 | * @sec: seconds to set |
| 364 | * @nsec: nanoseconds to set |
| 365 | * |
| 366 | * Set seconds and nanoseconds field of a timespec variable and |
| 367 | * normalize to the timespec storage format |
| 368 | * |
| 369 | * Note: The tv_nsec part is always in the range of |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 370 | * 0 <= tv_nsec < NSEC_PER_SEC |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 371 | * For negative values only the tv_sec field is negative ! |
| 372 | */ |
Ingo Molnar | f481890 | 2006-01-09 20:52:23 -0800 | [diff] [blame] | 373 | void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec) |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 374 | { |
| 375 | while (nsec >= NSEC_PER_SEC) { |
| 376 | nsec -= NSEC_PER_SEC; |
| 377 | ++sec; |
| 378 | } |
| 379 | while (nsec < 0) { |
| 380 | nsec += NSEC_PER_SEC; |
| 381 | --sec; |
| 382 | } |
| 383 | ts->tv_sec = sec; |
| 384 | ts->tv_nsec = nsec; |
| 385 | } |
YOSHIFUJI Hideaki | 7c3f944 | 2008-04-21 19:45:12 -0700 | [diff] [blame] | 386 | EXPORT_SYMBOL(set_normalized_timespec); |
Thomas Gleixner | 753be62 | 2006-01-09 20:52:22 -0800 | [diff] [blame] | 387 | |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 388 | /** |
| 389 | * ns_to_timespec - Convert nanoseconds to timespec |
| 390 | * @nsec: the nanoseconds value to be converted |
| 391 | * |
| 392 | * Returns the timespec representation of the nsec parameter. |
| 393 | */ |
Roman Zippel | df869b6 | 2006-03-26 01:38:11 -0800 | [diff] [blame] | 394 | struct timespec ns_to_timespec(const s64 nsec) |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 395 | { |
| 396 | struct timespec ts; |
Roman Zippel | f8bd225 | 2008-05-01 04:34:31 -0700 | [diff] [blame] | 397 | s32 rem; |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 398 | |
George Anzinger | 88fc389 | 2006-02-03 03:04:20 -0800 | [diff] [blame] | 399 | if (!nsec) |
| 400 | return (struct timespec) {0, 0}; |
| 401 | |
Roman Zippel | f8bd225 | 2008-05-01 04:34:31 -0700 | [diff] [blame] | 402 | ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); |
| 403 | if (unlikely(rem < 0)) { |
| 404 | ts.tv_sec--; |
| 405 | rem += NSEC_PER_SEC; |
| 406 | } |
| 407 | ts.tv_nsec = rem; |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 408 | |
| 409 | return ts; |
| 410 | } |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 411 | EXPORT_SYMBOL(ns_to_timespec); |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 412 | |
| 413 | /** |
| 414 | * ns_to_timeval - Convert nanoseconds to timeval |
| 415 | * @nsec: the nanoseconds value to be converted |
| 416 | * |
| 417 | * Returns the timeval representation of the nsec parameter. |
| 418 | */ |
Roman Zippel | df869b6 | 2006-03-26 01:38:11 -0800 | [diff] [blame] | 419 | struct timeval ns_to_timeval(const s64 nsec) |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 420 | { |
| 421 | struct timespec ts = ns_to_timespec(nsec); |
| 422 | struct timeval tv; |
| 423 | |
| 424 | tv.tv_sec = ts.tv_sec; |
| 425 | tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000; |
| 426 | |
| 427 | return tv; |
| 428 | } |
Eric Dumazet | b7aa0bf | 2007-04-19 16:16:32 -0700 | [diff] [blame] | 429 | EXPORT_SYMBOL(ns_to_timeval); |
Thomas Gleixner | f8f46da | 2006-01-09 20:52:30 -0800 | [diff] [blame] | 430 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 431 | /* |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 432 | * When we convert to jiffies then we interpret incoming values |
| 433 | * the following way: |
| 434 | * |
| 435 | * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) |
| 436 | * |
| 437 | * - 'too large' values [that would result in larger than |
| 438 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
| 439 | * |
| 440 | * - all other values are converted to jiffies by either multiplying |
| 441 | * the input value by a factor or dividing it with a factor |
| 442 | * |
| 443 | * We must also be careful about 32-bit overflows. |
| 444 | */ |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 445 | unsigned long msecs_to_jiffies(const unsigned int m) |
| 446 | { |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 447 | /* |
| 448 | * Negative value, means infinite timeout: |
| 449 | */ |
| 450 | if ((int)m < 0) |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 451 | return MAX_JIFFY_OFFSET; |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 452 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 453 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 454 | /* |
| 455 | * HZ is equal to or smaller than 1000, and 1000 is a nice |
| 456 | * round multiple of HZ, divide with the factor between them, |
| 457 | * but round upwards: |
| 458 | */ |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 459 | return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ); |
| 460 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 461 | /* |
| 462 | * HZ is larger than 1000, and HZ is a nice round multiple of |
| 463 | * 1000 - simply multiply with the factor between them. |
| 464 | * |
| 465 | * But first make sure the multiplication result cannot |
| 466 | * overflow: |
| 467 | */ |
| 468 | if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| 469 | return MAX_JIFFY_OFFSET; |
| 470 | |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 471 | return m * (HZ / MSEC_PER_SEC); |
| 472 | #else |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 473 | /* |
| 474 | * Generic case - multiply, round and divide. But first |
| 475 | * check that if we are doing a net multiplication, that |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 476 | * we wouldn't overflow: |
Ingo Molnar | 41cf544 | 2007-02-16 01:27:28 -0800 | [diff] [blame] | 477 | */ |
| 478 | if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| 479 | return MAX_JIFFY_OFFSET; |
| 480 | |
H. Peter Anvin | b9095fd | 2008-05-02 16:18:42 -0700 | [diff] [blame] | 481 | return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 482 | >> MSEC_TO_HZ_SHR32; |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 483 | #endif |
| 484 | } |
| 485 | EXPORT_SYMBOL(msecs_to_jiffies); |
| 486 | |
| 487 | unsigned long usecs_to_jiffies(const unsigned int u) |
| 488 | { |
| 489 | if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) |
| 490 | return MAX_JIFFY_OFFSET; |
| 491 | #if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ) |
| 492 | return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ); |
| 493 | #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) |
| 494 | return u * (HZ / USEC_PER_SEC); |
| 495 | #else |
H. Peter Anvin | b9095fd | 2008-05-02 16:18:42 -0700 | [diff] [blame] | 496 | return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32) |
H. Peter Anvin | bdc8078 | 2008-02-08 04:21:26 -0800 | [diff] [blame] | 497 | >> USEC_TO_HZ_SHR32; |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 498 | #endif |
| 499 | } |
| 500 | EXPORT_SYMBOL(usecs_to_jiffies); |
| 501 | |
| 502 | /* |
| 503 | * The TICK_NSEC - 1 rounds up the value to the next resolution. Note |
| 504 | * that a remainder subtract here would not do the right thing as the |
| 505 | * resolution values don't fall on second boundries. I.e. the line: |
| 506 | * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. |
| 507 | * |
| 508 | * Rather, we just shift the bits off the right. |
| 509 | * |
| 510 | * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec |
| 511 | * value to a scaled second value. |
| 512 | */ |
| 513 | unsigned long |
| 514 | timespec_to_jiffies(const struct timespec *value) |
| 515 | { |
| 516 | unsigned long sec = value->tv_sec; |
| 517 | long nsec = value->tv_nsec + TICK_NSEC - 1; |
| 518 | |
| 519 | if (sec >= MAX_SEC_IN_JIFFIES){ |
| 520 | sec = MAX_SEC_IN_JIFFIES; |
| 521 | nsec = 0; |
| 522 | } |
| 523 | return (((u64)sec * SEC_CONVERSION) + |
| 524 | (((u64)nsec * NSEC_CONVERSION) >> |
| 525 | (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; |
| 526 | |
| 527 | } |
| 528 | EXPORT_SYMBOL(timespec_to_jiffies); |
| 529 | |
| 530 | void |
| 531 | jiffies_to_timespec(const unsigned long jiffies, struct timespec *value) |
| 532 | { |
| 533 | /* |
| 534 | * Convert jiffies to nanoseconds and separate with |
| 535 | * one divide. |
| 536 | */ |
Roman Zippel | f8bd225 | 2008-05-01 04:34:31 -0700 | [diff] [blame] | 537 | u32 rem; |
| 538 | value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, |
| 539 | NSEC_PER_SEC, &rem); |
| 540 | value->tv_nsec = rem; |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 541 | } |
| 542 | EXPORT_SYMBOL(jiffies_to_timespec); |
| 543 | |
| 544 | /* Same for "timeval" |
| 545 | * |
| 546 | * Well, almost. The problem here is that the real system resolution is |
| 547 | * in nanoseconds and the value being converted is in micro seconds. |
| 548 | * Also for some machines (those that use HZ = 1024, in-particular), |
| 549 | * there is a LARGE error in the tick size in microseconds. |
| 550 | |
| 551 | * The solution we use is to do the rounding AFTER we convert the |
| 552 | * microsecond part. Thus the USEC_ROUND, the bits to be shifted off. |
| 553 | * Instruction wise, this should cost only an additional add with carry |
| 554 | * instruction above the way it was done above. |
| 555 | */ |
| 556 | unsigned long |
| 557 | timeval_to_jiffies(const struct timeval *value) |
| 558 | { |
| 559 | unsigned long sec = value->tv_sec; |
| 560 | long usec = value->tv_usec; |
| 561 | |
| 562 | if (sec >= MAX_SEC_IN_JIFFIES){ |
| 563 | sec = MAX_SEC_IN_JIFFIES; |
| 564 | usec = 0; |
| 565 | } |
| 566 | return (((u64)sec * SEC_CONVERSION) + |
| 567 | (((u64)usec * USEC_CONVERSION + USEC_ROUND) >> |
| 568 | (USEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; |
| 569 | } |
Thomas Bittermann | 456a09d | 2007-04-04 22:20:54 +0200 | [diff] [blame] | 570 | EXPORT_SYMBOL(timeval_to_jiffies); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 571 | |
| 572 | void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value) |
| 573 | { |
| 574 | /* |
| 575 | * Convert jiffies to nanoseconds and separate with |
| 576 | * one divide. |
| 577 | */ |
Roman Zippel | f8bd225 | 2008-05-01 04:34:31 -0700 | [diff] [blame] | 578 | u32 rem; |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 579 | |
Roman Zippel | f8bd225 | 2008-05-01 04:34:31 -0700 | [diff] [blame] | 580 | value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, |
| 581 | NSEC_PER_SEC, &rem); |
| 582 | value->tv_usec = rem / NSEC_PER_USEC; |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 583 | } |
Thomas Bittermann | 456a09d | 2007-04-04 22:20:54 +0200 | [diff] [blame] | 584 | EXPORT_SYMBOL(jiffies_to_timeval); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 585 | |
| 586 | /* |
| 587 | * Convert jiffies/jiffies_64 to clock_t and back. |
| 588 | */ |
| 589 | clock_t jiffies_to_clock_t(long x) |
| 590 | { |
| 591 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 |
David Fries | 6ffc787 | 2008-02-06 01:38:04 -0800 | [diff] [blame] | 592 | # if HZ < USER_HZ |
| 593 | return x * (USER_HZ / HZ); |
| 594 | # else |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 595 | return x / (HZ / USER_HZ); |
David Fries | 6ffc787 | 2008-02-06 01:38:04 -0800 | [diff] [blame] | 596 | # endif |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 597 | #else |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 598 | return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 599 | #endif |
| 600 | } |
| 601 | EXPORT_SYMBOL(jiffies_to_clock_t); |
| 602 | |
| 603 | unsigned long clock_t_to_jiffies(unsigned long x) |
| 604 | { |
| 605 | #if (HZ % USER_HZ)==0 |
| 606 | if (x >= ~0UL / (HZ / USER_HZ)) |
| 607 | return ~0UL; |
| 608 | return x * (HZ / USER_HZ); |
| 609 | #else |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 610 | /* Don't worry about loss of precision here .. */ |
| 611 | if (x >= ~0UL / HZ * USER_HZ) |
| 612 | return ~0UL; |
| 613 | |
| 614 | /* .. but do try to contain it here */ |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 615 | return div_u64((u64)x * HZ, USER_HZ); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 616 | #endif |
| 617 | } |
| 618 | EXPORT_SYMBOL(clock_t_to_jiffies); |
| 619 | |
| 620 | u64 jiffies_64_to_clock_t(u64 x) |
| 621 | { |
| 622 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 |
David Fries | 6ffc787 | 2008-02-06 01:38:04 -0800 | [diff] [blame] | 623 | # if HZ < USER_HZ |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 624 | x = div_u64(x * USER_HZ, HZ); |
Andrew Morton | ec03d70 | 2008-02-06 01:38:06 -0800 | [diff] [blame] | 625 | # elif HZ > USER_HZ |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 626 | x = div_u64(x, HZ / USER_HZ); |
Andrew Morton | ec03d70 | 2008-02-06 01:38:06 -0800 | [diff] [blame] | 627 | # else |
| 628 | /* Nothing to do */ |
David Fries | 6ffc787 | 2008-02-06 01:38:04 -0800 | [diff] [blame] | 629 | # endif |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 630 | #else |
| 631 | /* |
| 632 | * There are better ways that don't overflow early, |
| 633 | * but even this doesn't overflow in hundreds of years |
| 634 | * in 64 bits, so.. |
| 635 | */ |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 636 | x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 637 | #endif |
| 638 | return x; |
| 639 | } |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 640 | EXPORT_SYMBOL(jiffies_64_to_clock_t); |
| 641 | |
| 642 | u64 nsec_to_clock_t(u64 x) |
| 643 | { |
| 644 | #if (NSEC_PER_SEC % USER_HZ) == 0 |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 645 | return div_u64(x, NSEC_PER_SEC / USER_HZ); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 646 | #elif (USER_HZ % 512) == 0 |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 647 | return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 648 | #else |
| 649 | /* |
| 650 | * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, |
| 651 | * overflow after 64.99 years. |
| 652 | * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... |
| 653 | */ |
Roman Zippel | 71abb3a | 2008-05-01 04:34:26 -0700 | [diff] [blame] | 654 | return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 655 | #endif |
Ingo Molnar | 8b9365d | 2007-02-16 01:27:27 -0800 | [diff] [blame] | 656 | } |
| 657 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | #if (BITS_PER_LONG < 64) |
| 659 | u64 get_jiffies_64(void) |
| 660 | { |
| 661 | unsigned long seq; |
| 662 | u64 ret; |
| 663 | |
| 664 | do { |
| 665 | seq = read_seqbegin(&xtime_lock); |
| 666 | ret = jiffies_64; |
| 667 | } while (read_seqretry(&xtime_lock, seq)); |
| 668 | return ret; |
| 669 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | EXPORT_SYMBOL(get_jiffies_64); |
| 671 | #endif |
| 672 | |
| 673 | EXPORT_SYMBOL(jiffies); |
Thomas Gleixner | df0cc05 | 2008-08-31 08:09:53 -0700 | [diff] [blame] | 674 | |
| 675 | /* |
| 676 | * Add two timespec values and do a safety check for overflow. |
| 677 | * It's assumed that both values are valid (>= 0) |
| 678 | */ |
| 679 | struct timespec timespec_add_safe(const struct timespec lhs, |
| 680 | const struct timespec rhs) |
| 681 | { |
| 682 | struct timespec res; |
| 683 | |
| 684 | set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec, |
| 685 | lhs.tv_nsec + rhs.tv_nsec); |
| 686 | |
| 687 | if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec) |
| 688 | res.tv_sec = TIME_T_MAX; |
| 689 | |
| 690 | return res; |
| 691 | } |