Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1056 insertions, 0 deletions

diff --git a/kernel/time/time.c b/kernel/time/time.c
new file mode 100644
index 0000000000..642647f504
--- /dev/null
+++ b/kernel/time/time.c
@@ -0,0 +1,1056 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  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:
+ *
+ * 1993-09-02    Philip Gladstone
+ *      Created file with time related functions from sched/core.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 <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/timex.h>
+#include <linux/capability.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <linux/security.h>
+#include <linux/fs.h>
+#include <linux/math64.h>
+#include <linux/ptrace.h>
+
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <asm/unistd.h>
+
+#include <generated/timeconst.h>
+#include "timekeeping.h"
+
+/*
+ * 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).
+ */
+SYSCALL_DEFINE1(time, __kernel_old_time_t __user *, tloc)
+{
+	__kernel_old_time_t i = (__kernel_old_time_t)ktime_get_real_seconds();
+
+	if (tloc) {
+		if (put_user(i,tloc))
+			return -EFAULT;
+	}
+	force_successful_syscall_return();
+	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).
+ */
+
+SYSCALL_DEFINE1(stime, __kernel_old_time_t __user *, tptr)
+{
+	struct timespec64 tv;
+	int err;
+
+	if (get_user(tv.tv_sec, tptr))
+		return -EFAULT;
+
+	tv.tv_nsec = 0;
+
+	err = security_settime64(&tv, NULL);
+	if (err)
+		return err;
+
+	do_settimeofday64(&tv);
+	return 0;
+}
+
+#endif /* __ARCH_WANT_SYS_TIME */
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+#ifdef __ARCH_WANT_SYS_TIME32
+
+/* old_time32_t is a 32 bit "long" and needs to get converted. */
+SYSCALL_DEFINE1(time32, old_time32_t __user *, tloc)
+{
+	old_time32_t i;
+
+	i = (old_time32_t)ktime_get_real_seconds();
+
+	if (tloc) {
+		if (put_user(i,tloc))
+			return -EFAULT;
+	}
+	force_successful_syscall_return();
+	return i;
+}
+
+SYSCALL_DEFINE1(stime32, old_time32_t __user *, tptr)
+{
+	struct timespec64 tv;
+	int err;
+
+	if (get_user(tv.tv_sec, tptr))
+		return -EFAULT;
+
+	tv.tv_nsec = 0;
+
+	err = security_settime64(&tv, NULL);
+	if (err)
+		return err;
+
+	do_settimeofday64(&tv);
+	return 0;
+}
+
+#endif /* __ARCH_WANT_SYS_TIME32 */
+#endif
+
+SYSCALL_DEFINE2(gettimeofday, struct __kernel_old_timeval __user *, tv,
+		struct timezone __user *, tz)
+{
+	if (likely(tv != NULL)) {
+		struct timespec64 ts;
+
+		ktime_get_real_ts64(&ts);
+		if (put_user(ts.tv_sec, &tv->tv_sec) ||
+		    put_user(ts.tv_nsec / 1000, &tv->tv_usec))
+			return -EFAULT;
+	}
+	if (unlikely(tz != NULL)) {
+		if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+/*
+ * 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_settimeofday64(const struct timespec64 *tv, const struct timezone *tz)
+{
+	static int firsttime = 1;
+	int error = 0;
+
+	if (tv && !timespec64_valid_settod(tv))
+		return -EINVAL;
+
+	error = security_settime64(tv, tz);
+	if (error)
+		return error;
+
+	if (tz) {
+		/* Verify we're within the +-15 hrs range */
+		if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
+			return -EINVAL;
+
+		sys_tz = *tz;
+		update_vsyscall_tz();
+		if (firsttime) {
+			firsttime = 0;
+			if (!tv)
+				timekeeping_warp_clock();
+		}
+	}
+	if (tv)
+		return do_settimeofday64(tv);
+	return 0;
+}
+
+SYSCALL_DEFINE2(settimeofday, struct __kernel_old_timeval __user *, tv,
+		struct timezone __user *, tz)
+{
+	struct timespec64 new_ts;
+	struct timezone new_tz;
+
+	if (tv) {
+		if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
+		    get_user(new_ts.tv_nsec, &tv->tv_usec))
+			return -EFAULT;
+
+		if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0)
+			return -EINVAL;
+
+		new_ts.tv_nsec *= NSEC_PER_USEC;
+	}
+	if (tz) {
+		if (copy_from_user(&new_tz, tz, sizeof(*tz)))
+			return -EFAULT;
+	}
+
+	return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(gettimeofday, struct old_timeval32 __user *, tv,
+		       struct timezone __user *, tz)
+{
+	if (tv) {
+		struct timespec64 ts;
+
+		ktime_get_real_ts64(&ts);
+		if (put_user(ts.tv_sec, &tv->tv_sec) ||
+		    put_user(ts.tv_nsec / 1000, &tv->tv_usec))
+			return -EFAULT;
+	}
+	if (tz) {
+		if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
+		       struct timezone __user *, tz)
+{
+	struct timespec64 new_ts;
+	struct timezone new_tz;
+
+	if (tv) {
+		if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
+		    get_user(new_ts.tv_nsec, &tv->tv_usec))
+			return -EFAULT;
+
+		if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0)
+			return -EINVAL;
+
+		new_ts.tv_nsec *= NSEC_PER_USEC;
+	}
+	if (tz) {
+		if (copy_from_user(&new_tz, tz, sizeof(*tz)))
+			return -EFAULT;
+	}
+
+	return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
+}
+#endif
+
+#ifdef CONFIG_64BIT
+SYSCALL_DEFINE1(adjtimex, struct __kernel_timex __user *, txc_p)
+{
+	struct __kernel_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 __kernel_timex)))
+		return -EFAULT;
+	ret = do_adjtimex(&txc);
+	return copy_to_user(txc_p, &txc, sizeof(struct __kernel_timex)) ? -EFAULT : ret;
+}
+#endif
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+int get_old_timex32(struct __kernel_timex *txc, const struct old_timex32 __user *utp)
+{
+	struct old_timex32 tx32;
+
+	memset(txc, 0, sizeof(struct __kernel_timex));
+	if (copy_from_user(&tx32, utp, sizeof(struct old_timex32)))
+		return -EFAULT;
+
+	txc->modes = tx32.modes;
+	txc->offset = tx32.offset;
+	txc->freq = tx32.freq;
+	txc->maxerror = tx32.maxerror;
+	txc->esterror = tx32.esterror;
+	txc->status = tx32.status;
+	txc->constant = tx32.constant;
+	txc->precision = tx32.precision;
+	txc->tolerance = tx32.tolerance;
+	txc->time.tv_sec = tx32.time.tv_sec;
+	txc->time.tv_usec = tx32.time.tv_usec;
+	txc->tick = tx32.tick;
+	txc->ppsfreq = tx32.ppsfreq;
+	txc->jitter = tx32.jitter;
+	txc->shift = tx32.shift;
+	txc->stabil = tx32.stabil;
+	txc->jitcnt = tx32.jitcnt;
+	txc->calcnt = tx32.calcnt;
+	txc->errcnt = tx32.errcnt;
+	txc->stbcnt = tx32.stbcnt;
+
+	return 0;
+}
+
+int put_old_timex32(struct old_timex32 __user *utp, const struct __kernel_timex *txc)
+{
+	struct old_timex32 tx32;
+
+	memset(&tx32, 0, sizeof(struct old_timex32));
+	tx32.modes = txc->modes;
+	tx32.offset = txc->offset;
+	tx32.freq = txc->freq;
+	tx32.maxerror = txc->maxerror;
+	tx32.esterror = txc->esterror;
+	tx32.status = txc->status;
+	tx32.constant = txc->constant;
+	tx32.precision = txc->precision;
+	tx32.tolerance = txc->tolerance;
+	tx32.time.tv_sec = txc->time.tv_sec;
+	tx32.time.tv_usec = txc->time.tv_usec;
+	tx32.tick = txc->tick;
+	tx32.ppsfreq = txc->ppsfreq;
+	tx32.jitter = txc->jitter;
+	tx32.shift = txc->shift;
+	tx32.stabil = txc->stabil;
+	tx32.jitcnt = txc->jitcnt;
+	tx32.calcnt = txc->calcnt;
+	tx32.errcnt = txc->errcnt;
+	tx32.stbcnt = txc->stbcnt;
+	tx32.tai = txc->tai;
+	if (copy_to_user(utp, &tx32, sizeof(struct old_timex32)))
+		return -EFAULT;
+	return 0;
+}
+
+SYSCALL_DEFINE1(adjtimex_time32, struct old_timex32 __user *, utp)
+{
+	struct __kernel_timex txc;
+	int err, ret;
+
+	err = get_old_timex32(&txc, utp);
+	if (err)
+		return err;
+
+	ret = do_adjtimex(&txc);
+
+	err = put_old_timex32(utp, &txc);
+	if (err)
+		return err;
+
+	return ret;
+}
+#endif
+
+/**
+ * jiffies_to_msecs - Convert jiffies to milliseconds
+ * @j: jiffies value
+ *
+ * Avoid unnecessary multiplications/divisions in the
+ * two most common HZ cases.
+ *
+ * Return: milliseconds value
+ */
+unsigned int jiffies_to_msecs(const unsigned long j)
+{
+#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
+	return (MSEC_PER_SEC / HZ) * j;
+#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
+	return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
+#else
+# if BITS_PER_LONG == 32
+	return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >>
+	       HZ_TO_MSEC_SHR32;
+# else
+	return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
+# endif
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_msecs);
+
+/**
+ * jiffies_to_usecs - Convert jiffies to microseconds
+ * @j: jiffies value
+ *
+ * Return: microseconds value
+ */
+unsigned int jiffies_to_usecs(const unsigned long j)
+{
+	/*
+	 * Hz usually doesn't go much further MSEC_PER_SEC.
+	 * jiffies_to_usecs() and usecs_to_jiffies() depend on that.
+	 */
+	BUILD_BUG_ON(HZ > USEC_PER_SEC);
+
+#if !(USEC_PER_SEC % HZ)
+	return (USEC_PER_SEC / HZ) * j;
+#else
+# if BITS_PER_LONG == 32
+	return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
+# else
+	return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
+# endif
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_usecs);
+
+/**
+ * mktime64 - Converts date to seconds.
+ * @year0: year to convert
+ * @mon0: month to convert
+ * @day: day to convert
+ * @hour: hour to convert
+ * @min: minute to convert
+ * @sec: second to convert
+ *
+ * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
+ * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
+ * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
+ *
+ * [For the Julian calendar (which was used in Russia before 1917,
+ * Britain & colonies before 1752, anywhere else before 1582,
+ * and is still in use by some communities) leave out the
+ * -year/100+year/400 terms, and add 10.]
+ *
+ * This algorithm was first published by Gauss (I think).
+ *
+ * A leap second can be indicated by calling this function with sec as
+ * 60 (allowable under ISO 8601).  The leap second is treated the same
+ * as the following second since they don't exist in UNIX time.
+ *
+ * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
+ * tomorrow - (allowable under ISO 8601) is supported.
+ *
+ * Return: seconds since the epoch time for the given input date
+ */
+time64_t mktime64(const unsigned int year0, const unsigned int mon0,
+		const unsigned int day, const unsigned int hour,
+		const unsigned int min, const unsigned int sec)
+{
+	unsigned int mon = mon0, year = year0;
+
+	/* 1..12 -> 11,12,1..10 */
+	if (0 >= (int) (mon -= 2)) {
+		mon += 12;	/* Puts Feb last since it has leap day */
+		year -= 1;
+	}
+
+	return ((((time64_t)
+		  (year/4 - year/100 + year/400 + 367*mon/12 + day) +
+		  year*365 - 719499
+	    )*24 + hour /* now have hours - midnight tomorrow handled here */
+	  )*60 + min /* now have minutes */
+	)*60 + sec; /* finally seconds */
+}
+EXPORT_SYMBOL(mktime64);
+
+struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec)
+{
+	struct timespec64 ts = ns_to_timespec64(nsec);
+	struct __kernel_old_timeval tv;
+
+	tv.tv_sec = ts.tv_sec;
+	tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
+
+	return tv;
+}
+EXPORT_SYMBOL(ns_to_kernel_old_timeval);
+
+/**
+ * set_normalized_timespec64 - set timespec sec and nsec parts and normalize
+ *
+ * @ts:		pointer to timespec variable to be set
+ * @sec:	seconds to set
+ * @nsec:	nanoseconds to set
+ *
+ * Set seconds and nanoseconds field of a timespec variable and
+ * normalize to the timespec storage format
+ *
+ * Note: The tv_nsec part is always in the range of 0 <= tv_nsec < NSEC_PER_SEC.
+ * For negative values only the tv_sec field is negative !
+ */
+void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
+{
+	while (nsec >= NSEC_PER_SEC) {
+		/*
+		 * The following asm() prevents the compiler from
+		 * optimising this loop into a modulo operation. See
+		 * also __iter_div_u64_rem() in include/linux/time.h
+		 */
+		asm("" : "+rm"(nsec));
+		nsec -= NSEC_PER_SEC;
+		++sec;
+	}
+	while (nsec < 0) {
+		asm("" : "+rm"(nsec));
+		nsec += NSEC_PER_SEC;
+		--sec;
+	}
+	ts->tv_sec = sec;
+	ts->tv_nsec = nsec;
+}
+EXPORT_SYMBOL(set_normalized_timespec64);
+
+/**
+ * ns_to_timespec64 - Convert nanoseconds to timespec64
+ * @nsec:       the nanoseconds value to be converted
+ *
+ * Return: the timespec64 representation of the nsec parameter.
+ */
+struct timespec64 ns_to_timespec64(s64 nsec)
+{
+	struct timespec64 ts = { 0, 0 };
+	s32 rem;
+
+	if (likely(nsec > 0)) {
+		ts.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
+		ts.tv_nsec = rem;
+	} else if (nsec < 0) {
+		/*
+		 * With negative times, tv_sec points to the earlier
+		 * second, and tv_nsec counts the nanoseconds since
+		 * then, so tv_nsec is always a positive number.
+		 */
+		ts.tv_sec = -div_u64_rem(-nsec - 1, NSEC_PER_SEC, &rem) - 1;
+		ts.tv_nsec = NSEC_PER_SEC - rem - 1;
+	}
+
+	return ts;
+}
+EXPORT_SYMBOL(ns_to_timespec64);
+
+/**
+ * __msecs_to_jiffies: - convert milliseconds to jiffies
+ * @m:	time in milliseconds
+ *
+ * conversion is done as follows:
+ *
+ * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
+ *
+ * - 'too large' values [that would result in larger than
+ *   MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
+ *
+ * - all other values are converted to jiffies by either multiplying
+ *   the input value by a factor or dividing it with a factor and
+ *   handling any 32-bit overflows.
+ *   for the details see __msecs_to_jiffies()
+ *
+ * __msecs_to_jiffies() checks for the passed in value being a constant
+ * via __builtin_constant_p() allowing gcc to eliminate most of the
+ * code, __msecs_to_jiffies() is called if the value passed does not
+ * allow constant folding and the actual conversion must be done at
+ * runtime.
+ * The _msecs_to_jiffies helpers are the HZ dependent conversion
+ * routines found in include/linux/jiffies.h
+ *
+ * Return: jiffies value
+ */
+unsigned long __msecs_to_jiffies(const unsigned int m)
+{
+	/*
+	 * Negative value, means infinite timeout:
+	 */
+	if ((int)m < 0)
+		return MAX_JIFFY_OFFSET;
+	return _msecs_to_jiffies(m);
+}
+EXPORT_SYMBOL(__msecs_to_jiffies);
+
+/**
+ * __usecs_to_jiffies: - convert microseconds to jiffies
+ * @u:	time in milliseconds
+ *
+ * Return: jiffies value
+ */
+unsigned long __usecs_to_jiffies(const unsigned int u)
+{
+	if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
+		return MAX_JIFFY_OFFSET;
+	return _usecs_to_jiffies(u);
+}
+EXPORT_SYMBOL(__usecs_to_jiffies);
+
+/**
+ * timespec64_to_jiffies - convert a timespec64 value to jiffies
+ * @value: pointer to &struct timespec64
+ *
+ * The TICK_NSEC - 1 rounds up the value to the next resolution.  Note
+ * that a remainder subtract here would not do the right thing as the
+ * resolution values don't fall on second boundaries.  I.e. the line:
+ * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
+ * Note that due to the small error in the multiplier here, this
+ * rounding is incorrect for sufficiently large values of tv_nsec, but
+ * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
+ * OK.
+ *
+ * Rather, we just shift the bits off the right.
+ *
+ * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
+ * value to a scaled second value.
+ *
+ * Return: jiffies value
+ */
+unsigned long
+timespec64_to_jiffies(const struct timespec64 *value)
+{
+	u64 sec = value->tv_sec;
+	long nsec = value->tv_nsec + TICK_NSEC - 1;
+
+	if (sec >= MAX_SEC_IN_JIFFIES){
+		sec = MAX_SEC_IN_JIFFIES;
+		nsec = 0;
+	}
+	return ((sec * SEC_CONVERSION) +
+		(((u64)nsec * NSEC_CONVERSION) >>
+		 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
+
+}
+EXPORT_SYMBOL(timespec64_to_jiffies);
+
+/**
+ * jiffies_to_timespec64 - convert jiffies value to &struct timespec64
+ * @jiffies: jiffies value
+ * @value: pointer to &struct timespec64
+ */
+void
+jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
+{
+	/*
+	 * Convert jiffies to nanoseconds and separate with
+	 * one divide.
+	 */
+	u32 rem;
+	value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
+				    NSEC_PER_SEC, &rem);
+	value->tv_nsec = rem;
+}
+EXPORT_SYMBOL(jiffies_to_timespec64);
+
+/*
+ * Convert jiffies/jiffies_64 to clock_t and back.
+ */
+
+/**
+ * jiffies_to_clock_t - Convert jiffies to clock_t
+ * @x: jiffies value
+ *
+ * Return: jiffies converted to clock_t (CLOCKS_PER_SEC)
+ */
+clock_t jiffies_to_clock_t(unsigned long x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+# if HZ < USER_HZ
+	return x * (USER_HZ / HZ);
+# else
+	return x / (HZ / USER_HZ);
+# endif
+#else
+	return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_clock_t);
+
+/**
+ * clock_t_to_jiffies - Convert clock_t to jiffies
+ * @x: clock_t value
+ *
+ * Return: clock_t value converted to jiffies
+ */
+unsigned long clock_t_to_jiffies(unsigned long x)
+{
+#if (HZ % USER_HZ)==0
+	if (x >= ~0UL / (HZ / USER_HZ))
+		return ~0UL;
+	return x * (HZ / USER_HZ);
+#else
+	/* Don't worry about loss of precision here .. */
+	if (x >= ~0UL / HZ * USER_HZ)
+		return ~0UL;
+
+	/* .. but do try to contain it here */
+	return div_u64((u64)x * HZ, USER_HZ);
+#endif
+}
+EXPORT_SYMBOL(clock_t_to_jiffies);
+
+/**
+ * jiffies_64_to_clock_t - Convert jiffies_64 to clock_t
+ * @x: jiffies_64 value
+ *
+ * Return: jiffies_64 value converted to 64-bit "clock_t" (CLOCKS_PER_SEC)
+ */
+u64 jiffies_64_to_clock_t(u64 x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+# if HZ < USER_HZ
+	x = div_u64(x * USER_HZ, HZ);
+# elif HZ > USER_HZ
+	x = div_u64(x, HZ / USER_HZ);
+# else
+	/* Nothing to do */
+# endif
+#else
+	/*
+	 * There are better ways that don't overflow early,
+	 * but even this doesn't overflow in hundreds of years
+	 * in 64 bits, so..
+	 */
+	x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
+#endif
+	return x;
+}
+EXPORT_SYMBOL(jiffies_64_to_clock_t);
+
+/**
+ * nsec_to_clock_t - Convert nsec value to clock_t
+ * @x: nsec value
+ *
+ * Return: nsec value converted to 64-bit "clock_t" (CLOCKS_PER_SEC)
+ */
+u64 nsec_to_clock_t(u64 x)
+{
+#if (NSEC_PER_SEC % USER_HZ) == 0
+	return div_u64(x, NSEC_PER_SEC / USER_HZ);
+#elif (USER_HZ % 512) == 0
+	return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
+#else
+	/*
+         * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
+         * overflow after 64.99 years.
+         * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
+         */
+	return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
+#endif
+}
+
+/**
+ * jiffies64_to_nsecs - Convert jiffies64 to nanoseconds
+ * @j: jiffies64 value
+ *
+ * Return: nanoseconds value
+ */
+u64 jiffies64_to_nsecs(u64 j)
+{
+#if !(NSEC_PER_SEC % HZ)
+	return (NSEC_PER_SEC / HZ) * j;
+# else
+	return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
+#endif
+}
+EXPORT_SYMBOL(jiffies64_to_nsecs);
+
+/**
+ * jiffies64_to_msecs - Convert jiffies64 to milliseconds
+ * @j: jiffies64 value
+ *
+ * Return: milliseconds value
+ */
+u64 jiffies64_to_msecs(const u64 j)
+{
+#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
+	return (MSEC_PER_SEC / HZ) * j;
+#else
+	return div_u64(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
+#endif
+}
+EXPORT_SYMBOL(jiffies64_to_msecs);
+
+/**
+ * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
+ *
+ * @n:	nsecs in u64
+ *
+ * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
+ * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
+ * for scheduler, not for use in device drivers to calculate timeout value.
+ *
+ * note:
+ *   NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
+ *   ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ *
+ * Return: nsecs converted to jiffies64 value
+ */
+u64 nsecs_to_jiffies64(u64 n)
+{
+#if (NSEC_PER_SEC % HZ) == 0
+	/* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
+	return div_u64(n, NSEC_PER_SEC / HZ);
+#elif (HZ % 512) == 0
+	/* overflow after 292 years if HZ = 1024 */
+	return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
+#else
+	/*
+	 * Generic case - optimized for cases where HZ is a multiple of 3.
+	 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
+	 */
+	return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
+#endif
+}
+EXPORT_SYMBOL(nsecs_to_jiffies64);
+
+/**
+ * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
+ *
+ * @n:	nsecs in u64
+ *
+ * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
+ * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
+ * for scheduler, not for use in device drivers to calculate timeout value.
+ *
+ * note:
+ *   NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
+ *   ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ *
+ * Return: nsecs converted to jiffies value
+ */
+unsigned long nsecs_to_jiffies(u64 n)
+{
+	return (unsigned long)nsecs_to_jiffies64(n);
+}
+EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
+
+/**
+ * timespec64_add_safe - Add two timespec64 values and do a safety check
+ * for overflow.
+ * @lhs: first (left) timespec64 to add
+ * @rhs: second (right) timespec64 to add
+ *
+ * It's assumed that both values are valid (>= 0).
+ * And, each timespec64 is in normalized form.
+ *
+ * Return: sum of @lhs + @rhs
+ */
+struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
+				const struct timespec64 rhs)
+{
+	struct timespec64 res;
+
+	set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
+			lhs.tv_nsec + rhs.tv_nsec);
+
+	if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
+		res.tv_sec = TIME64_MAX;
+		res.tv_nsec = 0;
+	}
+
+	return res;
+}
+
+/**
+ * get_timespec64 - get user's time value into kernel space
+ * @ts: destination &struct timespec64
+ * @uts: user's time value as &struct __kernel_timespec
+ *
+ * Handles compat or 32-bit modes.
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int get_timespec64(struct timespec64 *ts,
+		   const struct __kernel_timespec __user *uts)
+{
+	struct __kernel_timespec kts;
+	int ret;
+
+	ret = copy_from_user(&kts, uts, sizeof(kts));
+	if (ret)
+		return -EFAULT;
+
+	ts->tv_sec = kts.tv_sec;
+
+	/* Zero out the padding in compat mode */
+	if (in_compat_syscall())
+		kts.tv_nsec &= 0xFFFFFFFFUL;
+
+	/* In 32-bit mode, this drops the padding */
+	ts->tv_nsec = kts.tv_nsec;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_timespec64);
+
+/**
+ * put_timespec64 - convert timespec64 value to __kernel_timespec format and
+ * 		    copy the latter to userspace
+ * @ts: input &struct timespec64
+ * @uts: user's &struct __kernel_timespec
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int put_timespec64(const struct timespec64 *ts,
+		   struct __kernel_timespec __user *uts)
+{
+	struct __kernel_timespec kts = {
+		.tv_sec = ts->tv_sec,
+		.tv_nsec = ts->tv_nsec
+	};
+
+	return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(put_timespec64);
+
+static int __get_old_timespec32(struct timespec64 *ts64,
+				   const struct old_timespec32 __user *cts)
+{
+	struct old_timespec32 ts;
+	int ret;
+
+	ret = copy_from_user(&ts, cts, sizeof(ts));
+	if (ret)
+		return -EFAULT;
+
+	ts64->tv_sec = ts.tv_sec;
+	ts64->tv_nsec = ts.tv_nsec;
+
+	return 0;
+}
+
+static int __put_old_timespec32(const struct timespec64 *ts64,
+				   struct old_timespec32 __user *cts)
+{
+	struct old_timespec32 ts = {
+		.tv_sec = ts64->tv_sec,
+		.tv_nsec = ts64->tv_nsec
+	};
+	return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
+}
+
+/**
+ * get_old_timespec32 - get user's old-format time value into kernel space
+ * @ts: destination &struct timespec64
+ * @uts: user's old-format time value (&struct old_timespec32)
+ *
+ * Handles X86_X32_ABI compatibility conversion.
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
+{
+	if (COMPAT_USE_64BIT_TIME)
+		return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
+	else
+		return __get_old_timespec32(ts, uts);
+}
+EXPORT_SYMBOL_GPL(get_old_timespec32);
+
+/**
+ * put_old_timespec32 - convert timespec64 value to &struct old_timespec32 and
+ * 			copy the latter to userspace
+ * @ts: input &struct timespec64
+ * @uts: user's &struct old_timespec32
+ *
+ * Handles X86_X32_ABI compatibility conversion.
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
+{
+	if (COMPAT_USE_64BIT_TIME)
+		return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
+	else
+		return __put_old_timespec32(ts, uts);
+}
+EXPORT_SYMBOL_GPL(put_old_timespec32);
+
+/**
+ * get_itimerspec64 - get user's &struct __kernel_itimerspec into kernel space
+ * @it: destination &struct itimerspec64
+ * @uit: user's &struct __kernel_itimerspec
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int get_itimerspec64(struct itimerspec64 *it,
+			const struct __kernel_itimerspec __user *uit)
+{
+	int ret;
+
+	ret = get_timespec64(&it->it_interval, &uit->it_interval);
+	if (ret)
+		return ret;
+
+	ret = get_timespec64(&it->it_value, &uit->it_value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(get_itimerspec64);
+
+/**
+ * put_itimerspec64 - convert &struct itimerspec64 to __kernel_itimerspec format
+ * 		      and copy the latter to userspace
+ * @it: input &struct itimerspec64
+ * @uit: user's &struct __kernel_itimerspec
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int put_itimerspec64(const struct itimerspec64 *it,
+			struct __kernel_itimerspec __user *uit)
+{
+	int ret;
+
+	ret = put_timespec64(&it->it_interval, &uit->it_interval);
+	if (ret)
+		return ret;
+
+	ret = put_timespec64(&it->it_value, &uit->it_value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(put_itimerspec64);
+
+/**
+ * get_old_itimerspec32 - get user's &struct old_itimerspec32 into kernel space
+ * @its: destination &struct itimerspec64
+ * @uits: user's &struct old_itimerspec32
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int get_old_itimerspec32(struct itimerspec64 *its,
+			const struct old_itimerspec32 __user *uits)
+{
+
+	if (__get_old_timespec32(&its->it_interval, &uits->it_interval) ||
+	    __get_old_timespec32(&its->it_value, &uits->it_value))
+		return -EFAULT;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_old_itimerspec32);
+
+/**
+ * put_old_itimerspec32 - convert &struct itimerspec64 to &struct
+ *			  old_itimerspec32 and copy the latter to userspace
+ * @its: input &struct itimerspec64
+ * @uits: user's &struct old_itimerspec32
+ *
+ * Return: %0 on success or negative errno on error
+ */
+int put_old_itimerspec32(const struct itimerspec64 *its,
+			struct old_itimerspec32 __user *uits)
+{
+	if (__put_old_timespec32(&its->it_interval, &uits->it_interval) ||
+	    __put_old_timespec32(&its->it_value, &uits->it_value))
+		return -EFAULT;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(put_old_itimerspec32);