From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- kernel/time.c | 599 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 599 insertions(+) create mode 100644 kernel/time.c (limited to 'kernel/time.c') diff --git a/kernel/time.c b/kernel/time.c new file mode 100644 index 000000000000..96fd0f499631 --- /dev/null +++ b/kernel/time.c @@ -0,0 +1,599 @@ +/* + * linux/kernel/time.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * This file contains the interface functions for the various + * time related system calls: time, stime, gettimeofday, settimeofday, + * adjtime + */ +/* + * Modification history kernel/time.c + * + * 1993-09-02 Philip Gladstone + * Created file with time related functions from sched.c and adjtimex() + * 1993-10-08 Torsten Duwe + * adjtime interface update and CMOS clock write code + * 1995-08-13 Torsten Duwe + * kernel PLL updated to 1994-12-13 specs (rfc-1589) + * 1999-01-16 Ulrich Windl + * Introduced error checking for many cases in adjtimex(). + * Updated NTP code according to technical memorandum Jan '96 + * "A Kernel Model for Precision Timekeeping" by Dave Mills + * Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10) + * (Even though the technical memorandum forbids it) + * 2004-07-14 Christoph Lameter + * Added getnstimeofday to allow the posix timer functions to return + * with nanosecond accuracy + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +/* + * The timezone where the local system is located. Used as a default by some + * programs who obtain this value by using gettimeofday. + */ +struct timezone sys_tz; + +EXPORT_SYMBOL(sys_tz); + +#ifdef __ARCH_WANT_SYS_TIME + +/* + * sys_time() can be implemented in user-level using + * sys_gettimeofday(). Is this for backwards compatibility? If so, + * why not move it into the appropriate arch directory (for those + * architectures that need it). + */ +asmlinkage long sys_time(time_t __user * tloc) +{ + time_t i; + struct timeval tv; + + do_gettimeofday(&tv); + i = tv.tv_sec; + + if (tloc) { + if (put_user(i,tloc)) + i = -EFAULT; + } + return i; +} + +/* + * sys_stime() can be implemented in user-level using + * sys_settimeofday(). Is this for backwards compatibility? If so, + * why not move it into the appropriate arch directory (for those + * architectures that need it). + */ + +asmlinkage long sys_stime(time_t __user *tptr) +{ + struct timespec tv; + int err; + + if (get_user(tv.tv_sec, tptr)) + return -EFAULT; + + tv.tv_nsec = 0; + + err = security_settime(&tv, NULL); + if (err) + return err; + + do_settimeofday(&tv); + return 0; +} + +#endif /* __ARCH_WANT_SYS_TIME */ + +asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz) +{ + if (likely(tv != NULL)) { + struct timeval ktv; + do_gettimeofday(&ktv); + if (copy_to_user(tv, &ktv, sizeof(ktv))) + return -EFAULT; + } + if (unlikely(tz != NULL)) { + if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) + return -EFAULT; + } + return 0; +} + +/* + * Adjust the time obtained from the CMOS to be UTC time instead of + * local time. + * + * This is ugly, but preferable to the alternatives. Otherwise we + * would either need to write a program to do it in /etc/rc (and risk + * confusion if the program gets run more than once; it would also be + * hard to make the program warp the clock precisely n hours) or + * compile in the timezone information into the kernel. Bad, bad.... + * + * - TYT, 1992-01-01 + * + * The best thing to do is to keep the CMOS clock in universal time (UTC) + * as real UNIX machines always do it. This avoids all headaches about + * daylight saving times and warping kernel clocks. + */ +inline static void warp_clock(void) +{ + write_seqlock_irq(&xtime_lock); + wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60; + xtime.tv_sec += sys_tz.tz_minuteswest * 60; + time_interpolator_reset(); + write_sequnlock_irq(&xtime_lock); + clock_was_set(); +} + +/* + * In case for some reason the CMOS clock has not already been running + * in UTC, but in some local time: The first time we set the timezone, + * we will warp the clock so that it is ticking UTC time instead of + * local time. Presumably, if someone is setting the timezone then we + * are running in an environment where the programs understand about + * timezones. This should be done at boot time in the /etc/rc script, + * as soon as possible, so that the clock can be set right. Otherwise, + * various programs will get confused when the clock gets warped. + */ + +int do_sys_settimeofday(struct timespec *tv, struct timezone *tz) +{ + static int firsttime = 1; + int error = 0; + + error = security_settime(tv, tz); + if (error) + return error; + + if (tz) { + /* SMP safe, global irq locking makes it work. */ + sys_tz = *tz; + if (firsttime) { + firsttime = 0; + if (!tv) + warp_clock(); + } + } + if (tv) + { + /* SMP safe, again the code in arch/foo/time.c should + * globally block out interrupts when it runs. + */ + return do_settimeofday(tv); + } + return 0; +} + +asmlinkage long sys_settimeofday(struct timeval __user *tv, + struct timezone __user *tz) +{ + struct timeval user_tv; + struct timespec new_ts; + struct timezone new_tz; + + if (tv) { + if (copy_from_user(&user_tv, tv, sizeof(*tv))) + return -EFAULT; + new_ts.tv_sec = user_tv.tv_sec; + new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; + } + if (tz) { + if (copy_from_user(&new_tz, tz, sizeof(*tz))) + return -EFAULT; + } + + return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL); +} + +long pps_offset; /* pps time offset (us) */ +long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */ + +long pps_freq; /* frequency offset (scaled ppm) */ +long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */ + +long pps_valid = PPS_VALID; /* pps signal watchdog counter */ + +int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */ + +long pps_jitcnt; /* jitter limit exceeded */ +long pps_calcnt; /* calibration intervals */ +long pps_errcnt; /* calibration errors */ +long pps_stbcnt; /* stability limit exceeded */ + +/* hook for a loadable hardpps kernel module */ +void (*hardpps_ptr)(struct timeval *); + +/* we call this to notify the arch when the clock is being + * controlled. If no such arch routine, do nothing. + */ +void __attribute__ ((weak)) notify_arch_cmos_timer(void) +{ + return; +} + +/* adjtimex mainly allows reading (and writing, if superuser) of + * kernel time-keeping variables. used by xntpd. + */ +int do_adjtimex(struct timex *txc) +{ + long ltemp, mtemp, save_adjust; + int result; + + /* In order to modify anything, you gotta be super-user! */ + if (txc->modes && !capable(CAP_SYS_TIME)) + return -EPERM; + + /* Now we validate the data before disabling interrupts */ + + if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) + /* singleshot must not be used with any other mode bits */ + if (txc->modes != ADJ_OFFSET_SINGLESHOT) + return -EINVAL; + + if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET)) + /* adjustment Offset limited to +- .512 seconds */ + if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE ) + return -EINVAL; + + /* if the quartz is off by more than 10% something is VERY wrong ! */ + if (txc->modes & ADJ_TICK) + if (txc->tick < 900000/USER_HZ || + txc->tick > 1100000/USER_HZ) + return -EINVAL; + + write_seqlock_irq(&xtime_lock); + result = time_state; /* mostly `TIME_OK' */ + + /* Save for later - semantics of adjtime is to return old value */ + save_adjust = time_next_adjust ? time_next_adjust : time_adjust; + +#if 0 /* STA_CLOCKERR is never set yet */ + time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */ +#endif + /* If there are input parameters, then process them */ + if (txc->modes) + { + if (txc->modes & ADJ_STATUS) /* only set allowed bits */ + time_status = (txc->status & ~STA_RONLY) | + (time_status & STA_RONLY); + + if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */ + if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) { + result = -EINVAL; + goto leave; + } + time_freq = txc->freq - pps_freq; + } + + if (txc->modes & ADJ_MAXERROR) { + if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) { + result = -EINVAL; + goto leave; + } + time_maxerror = txc->maxerror; + } + + if (txc->modes & ADJ_ESTERROR) { + if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) { + result = -EINVAL; + goto leave; + } + time_esterror = txc->esterror; + } + + if (txc->modes & ADJ_TIMECONST) { /* p. 24 */ + if (txc->constant < 0) { /* NTP v4 uses values > 6 */ + result = -EINVAL; + goto leave; + } + time_constant = txc->constant; + } + + if (txc->modes & ADJ_OFFSET) { /* values checked earlier */ + if (txc->modes == ADJ_OFFSET_SINGLESHOT) { + /* adjtime() is independent from ntp_adjtime() */ + if ((time_next_adjust = txc->offset) == 0) + time_adjust = 0; + } + else if ( time_status & (STA_PLL | STA_PPSTIME) ) { + ltemp = (time_status & (STA_PPSTIME | STA_PPSSIGNAL)) == + (STA_PPSTIME | STA_PPSSIGNAL) ? + pps_offset : txc->offset; + + /* + * Scale the phase adjustment and + * clamp to the operating range. + */ + if (ltemp > MAXPHASE) + time_offset = MAXPHASE << SHIFT_UPDATE; + else if (ltemp < -MAXPHASE) + time_offset = -(MAXPHASE << SHIFT_UPDATE); + else + time_offset = ltemp << SHIFT_UPDATE; + + /* + * Select whether the frequency is to be controlled + * and in which mode (PLL or FLL). Clamp to the operating + * range. Ugly multiply/divide should be replaced someday. + */ + + if (time_status & STA_FREQHOLD || time_reftime == 0) + time_reftime = xtime.tv_sec; + mtemp = xtime.tv_sec - time_reftime; + time_reftime = xtime.tv_sec; + if (time_status & STA_FLL) { + if (mtemp >= MINSEC) { + ltemp = (time_offset / mtemp) << (SHIFT_USEC - + SHIFT_UPDATE); + if (ltemp < 0) + time_freq -= -ltemp >> SHIFT_KH; + else + time_freq += ltemp >> SHIFT_KH; + } else /* calibration interval too short (p. 12) */ + result = TIME_ERROR; + } else { /* PLL mode */ + if (mtemp < MAXSEC) { + ltemp *= mtemp; + if (ltemp < 0) + time_freq -= -ltemp >> (time_constant + + time_constant + + SHIFT_KF - SHIFT_USEC); + else + time_freq += ltemp >> (time_constant + + time_constant + + SHIFT_KF - SHIFT_USEC); + } else /* calibration interval too long (p. 12) */ + result = TIME_ERROR; + } + if (time_freq > time_tolerance) + time_freq = time_tolerance; + else if (time_freq < -time_tolerance) + time_freq = -time_tolerance; + } /* STA_PLL || STA_PPSTIME */ + } /* txc->modes & ADJ_OFFSET */ + if (txc->modes & ADJ_TICK) { + tick_usec = txc->tick; + tick_nsec = TICK_USEC_TO_NSEC(tick_usec); + } + } /* txc->modes */ +leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0 + || ((time_status & (STA_PPSFREQ|STA_PPSTIME)) != 0 + && (time_status & STA_PPSSIGNAL) == 0) + /* p. 24, (b) */ + || ((time_status & (STA_PPSTIME|STA_PPSJITTER)) + == (STA_PPSTIME|STA_PPSJITTER)) + /* p. 24, (c) */ + || ((time_status & STA_PPSFREQ) != 0 + && (time_status & (STA_PPSWANDER|STA_PPSERROR)) != 0)) + /* p. 24, (d) */ + result = TIME_ERROR; + + if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) + txc->offset = save_adjust; + else { + if (time_offset < 0) + txc->offset = -(-time_offset >> SHIFT_UPDATE); + else + txc->offset = time_offset >> SHIFT_UPDATE; + } + txc->freq = time_freq + pps_freq; + txc->maxerror = time_maxerror; + txc->esterror = time_esterror; + txc->status = time_status; + txc->constant = time_constant; + txc->precision = time_precision; + txc->tolerance = time_tolerance; + txc->tick = tick_usec; + txc->ppsfreq = pps_freq; + txc->jitter = pps_jitter >> PPS_AVG; + txc->shift = pps_shift; + txc->stabil = pps_stabil; + txc->jitcnt = pps_jitcnt; + txc->calcnt = pps_calcnt; + txc->errcnt = pps_errcnt; + txc->stbcnt = pps_stbcnt; + write_sequnlock_irq(&xtime_lock); + do_gettimeofday(&txc->time); + notify_arch_cmos_timer(); + return(result); +} + +asmlinkage long sys_adjtimex(struct timex __user *txc_p) +{ + struct timex txc; /* Local copy of parameter */ + int ret; + + /* Copy the user data space into the kernel copy + * structure. But bear in mind that the structures + * may change + */ + if(copy_from_user(&txc, txc_p, sizeof(struct timex))) + return -EFAULT; + ret = do_adjtimex(&txc); + return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret; +} + +inline struct timespec current_kernel_time(void) +{ + struct timespec now; + unsigned long seq; + + do { + seq = read_seqbegin(&xtime_lock); + + now = xtime; + } while (read_seqretry(&xtime_lock, seq)); + + return now; +} + +EXPORT_SYMBOL(current_kernel_time); + +/** + * current_fs_time - Return FS time + * @sb: Superblock. + * + * Return the current time truncated to the time granuality supported by + * the fs. + */ +struct timespec current_fs_time(struct super_block *sb) +{ + struct timespec now = current_kernel_time(); + return timespec_trunc(now, sb->s_time_gran); +} +EXPORT_SYMBOL(current_fs_time); + +/** + * timespec_trunc - Truncate timespec to a granuality + * @t: Timespec + * @gran: Granuality in ns. + * + * Truncate a timespec to a granuality. gran must be smaller than a second. + * Always rounds down. + * + * This function should be only used for timestamps returned by + * current_kernel_time() or CURRENT_TIME, not with do_gettimeofday() because + * it doesn't handle the better resolution of the later. + */ +struct timespec timespec_trunc(struct timespec t, unsigned gran) +{ + /* + * Division is pretty slow so avoid it for common cases. + * Currently current_kernel_time() never returns better than + * jiffies resolution. Exploit that. + */ + if (gran <= jiffies_to_usecs(1) * 1000) { + /* nothing */ + } else if (gran == 1000000000) { + t.tv_nsec = 0; + } else { + t.tv_nsec -= t.tv_nsec % gran; + } + return t; +} +EXPORT_SYMBOL(timespec_trunc); + +#ifdef CONFIG_TIME_INTERPOLATION +void getnstimeofday (struct timespec *tv) +{ + unsigned long seq,sec,nsec; + + do { + seq = read_seqbegin(&xtime_lock); + sec = xtime.tv_sec; + nsec = xtime.tv_nsec+time_interpolator_get_offset(); + } while (unlikely(read_seqretry(&xtime_lock, seq))); + + while (unlikely(nsec >= NSEC_PER_SEC)) { + nsec -= NSEC_PER_SEC; + ++sec; + } + tv->tv_sec = sec; + tv->tv_nsec = nsec; +} +EXPORT_SYMBOL_GPL(getnstimeofday); + +int do_settimeofday (struct timespec *tv) +{ + time_t wtm_sec, sec = tv->tv_sec; + long wtm_nsec, nsec = tv->tv_nsec; + + if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) + return -EINVAL; + + write_seqlock_irq(&xtime_lock); + { + /* + * This is revolting. We need to set "xtime" correctly. However, the value + * in this location is the value at the most recent update of wall time. + * Discover what correction gettimeofday would have done, and then undo + * it! + */ + nsec -= time_interpolator_get_offset(); + + wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); + wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); + + set_normalized_timespec(&xtime, sec, nsec); + set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); + + time_adjust = 0; /* stop active adjtime() */ + time_status |= STA_UNSYNC; + time_maxerror = NTP_PHASE_LIMIT; + time_esterror = NTP_PHASE_LIMIT; + time_interpolator_reset(); + } + write_sequnlock_irq(&xtime_lock); + clock_was_set(); + return 0; +} + +void do_gettimeofday (struct timeval *tv) +{ + unsigned long seq, nsec, usec, sec, offset; + do { + seq = read_seqbegin(&xtime_lock); + offset = time_interpolator_get_offset(); + sec = xtime.tv_sec; + nsec = xtime.tv_nsec; + } while (unlikely(read_seqretry(&xtime_lock, seq))); + + usec = (nsec + offset) / 1000; + + while (unlikely(usec >= USEC_PER_SEC)) { + usec -= USEC_PER_SEC; + ++sec; + } + + tv->tv_sec = sec; + tv->tv_usec = usec; +} + +EXPORT_SYMBOL(do_gettimeofday); + + +#else +/* + * Simulate gettimeofday using do_gettimeofday which only allows a timeval + * and therefore only yields usec accuracy + */ +void getnstimeofday(struct timespec *tv) +{ + struct timeval x; + + do_gettimeofday(&x); + tv->tv_sec = x.tv_sec; + tv->tv_nsec = x.tv_usec * NSEC_PER_USEC; +} +#endif + +#if (BITS_PER_LONG < 64) +u64 get_jiffies_64(void) +{ + unsigned long seq; + u64 ret; + + do { + seq = read_seqbegin(&xtime_lock); + ret = jiffies_64; + } while (read_seqretry(&xtime_lock, seq)); + return ret; +} + +EXPORT_SYMBOL(get_jiffies_64); +#endif + +EXPORT_SYMBOL(jiffies); -- cgit v1.2.2