*/
/*
* Modification history kernel/time.c
- *
+ *
* 1993-09-02 Philip Gladstone
- * Created file with time related functions from sched.c and adjtimex()
+ * 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
#include <linux/module.h>
#include <linux/timex.h>
#include <linux/capability.h>
+#include <linux/clocksource.h>
#include <linux/errno.h>
-#include <linux/smp_lock.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/fs.h>
-#include <linux/module.h>
+#include <linux/math64.h>
+#include <linux/ptrace.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
-/*
+#include "timeconst.h"
+
+/*
* The timezone where the local system is located. Used as a default by some
* programs who obtain this value by using gettimeofday.
*/
* why not move it into the appropriate arch directory (for those
* architectures that need it).
*/
-asmlinkage long sys_time(time_t __user * tloc)
+SYSCALL_DEFINE1(time, time_t __user *, tloc)
{
- time_t i;
- struct timeval tv;
-
- do_gettimeofday(&tv);
- i = tv.tv_sec;
+ time_t i = get_seconds();
if (tloc) {
if (put_user(i,tloc))
- i = -EFAULT;
+ return -EFAULT;
}
+ force_successful_syscall_return();
return i;
}
* why not move it into the appropriate arch directory (for those
* architectures that need it).
*/
-
-asmlinkage long sys_stime(time_t __user *tptr)
+
+SYSCALL_DEFINE1(stime, time_t __user *, tptr)
{
struct timespec tv;
int err;
#endif /* __ARCH_WANT_SYS_TIME */
-asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz)
+SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
+ struct timezone __user *, tz)
{
if (likely(tv != NULL)) {
struct timeval ktv;
/*
* 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
+ * 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
+ * - 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
*/
static inline 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();
+ struct timespec adjust;
+
+ adjust = current_kernel_time();
+ adjust.tv_sec += sys_tz.tz_minuteswest * 60;
+ do_settimeofday(&adjust);
}
/*
* various programs will get confused when the clock gets warped.
*/
-int do_sys_settimeofday(struct timespec *tv, struct timezone *tz)
+int do_sys_settimeofday(const struct timespec *tv, const struct timezone *tz)
{
static int firsttime = 1;
int error = 0;
if (tz) {
/* SMP safe, global irq locking makes it work. */
sys_tz = *tz;
+ update_vsyscall_tz();
if (firsttime) {
firsttime = 0;
if (!tv)
return 0;
}
-asmlinkage long sys_settimeofday(struct timeval __user *tv,
- struct timezone __user *tz)
+SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
+ struct timezone __user *, tz)
{
struct timeval user_tv;
struct timespec new_ts;
return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
}
-asmlinkage long sys_adjtimex(struct timex __user *txc_p)
+SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
{
struct timex txc; /* Local copy of parameter */
int ret;
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.
}
EXPORT_SYMBOL(current_fs_time);
+/*
+ * Convert jiffies to milliseconds and back.
+ *
+ * Avoid unnecessary multiplications/divisions in the
+ * two most common HZ cases:
+ */
+inline 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) >> HZ_TO_MSEC_SHR32;
+# else
+ return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
+# endif
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_msecs);
+
+inline unsigned int jiffies_to_usecs(const unsigned long j)
+{
+#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
+ return (USEC_PER_SEC / HZ) * j;
+#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
+ return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
+#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);
+
/**
* timespec_trunc - Truncate timespec to a granularity
* @t: Timespec
*
* 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.
+ * it doesn't handle the better resolution of the latter.
*/
struct timespec timespec_trunc(struct timespec t, unsigned gran)
{
}
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);
- {
- 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;
-}
-EXPORT_SYMBOL(do_settimeofday);
-
-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
-#ifndef CONFIG_GENERIC_TIME
-/*
- * 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;
-}
-EXPORT_SYMBOL_GPL(getnstimeofday);
-#endif
-#endif
-
/* 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.
* This algorithm was first published by Gauss (I think).
*
* WARNING: this function will overflow on 2106-02-07 06:28:16 on
- * machines were long is 32-bit! (However, as time_t is signed, we
+ * machines where long is 32-bit! (However, as time_t is signed, we
* will already get problems at other places on 2038-01-19 03:14:08)
*/
unsigned long
* normalize to the timespec storage format
*
* Note: The tv_nsec part is always in the range of
- * 0 <= tv_nsec < NSEC_PER_SEC
+ * 0 <= tv_nsec < NSEC_PER_SEC
* For negative values only the tv_sec field is negative !
*/
-void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec)
+void set_normalized_timespec(struct timespec *ts, time_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_timespec);
/**
* ns_to_timespec - Convert nanoseconds to timespec
struct timespec ns_to_timespec(const s64 nsec)
{
struct timespec ts;
+ s32 rem;
if (!nsec)
return (struct timespec) {0, 0};
- ts.tv_sec = div_long_long_rem_signed(nsec, NSEC_PER_SEC, &ts.tv_nsec);
- if (unlikely(nsec < 0))
- set_normalized_timespec(&ts, ts.tv_sec, ts.tv_nsec);
+ ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
+ if (unlikely(rem < 0)) {
+ ts.tv_sec--;
+ rem += NSEC_PER_SEC;
+ }
+ ts.tv_nsec = rem;
return ts;
}
+EXPORT_SYMBOL(ns_to_timespec);
/**
* ns_to_timeval - Convert nanoseconds to timeval
return tv;
}
-
-/*
- * Convert jiffies to milliseconds and back.
- *
- * Avoid unnecessary multiplications/divisions in the
- * two most common HZ cases:
- */
-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
- return (j * MSEC_PER_SEC) / HZ;
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_msecs);
-
-unsigned int jiffies_to_usecs(const unsigned long j)
-{
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
- return (USEC_PER_SEC / HZ) * j;
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
- return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
-#else
- return (j * USEC_PER_SEC) / HZ;
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_usecs);
+EXPORT_SYMBOL(ns_to_timeval);
/*
* When we convert to jiffies then we interpret incoming values
/*
* Generic case - multiply, round and divide. But first
* check that if we are doing a net multiplication, that
- * we wouldnt overflow:
+ * we wouldn't overflow:
*/
if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
return MAX_JIFFY_OFFSET;
- return (m * HZ + MSEC_PER_SEC - 1) / MSEC_PER_SEC;
+ return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
+ >> MSEC_TO_HZ_SHR32;
#endif
}
EXPORT_SYMBOL(msecs_to_jiffies);
#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
return u * (HZ / USEC_PER_SEC);
#else
- return (u * HZ + USEC_PER_SEC - 1) / USEC_PER_SEC;
+ return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
+ >> USEC_TO_HZ_SHR32;
#endif
}
EXPORT_SYMBOL(usecs_to_jiffies);
* Convert jiffies to nanoseconds and separate with
* one divide.
*/
- u64 nsec = (u64)jiffies * TICK_NSEC;
- value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_nsec);
+ u32 rem;
+ value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
+ NSEC_PER_SEC, &rem);
+ value->tv_nsec = rem;
}
EXPORT_SYMBOL(jiffies_to_timespec);
* Convert jiffies to nanoseconds and separate with
* one divide.
*/
- u64 nsec = (u64)jiffies * TICK_NSEC;
- long tv_usec;
+ u32 rem;
- value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tv_usec);
- tv_usec /= NSEC_PER_USEC;
- value->tv_usec = tv_usec;
+ value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
+ NSEC_PER_SEC, &rem);
+ value->tv_usec = rem / NSEC_PER_USEC;
}
EXPORT_SYMBOL(jiffies_to_timeval);
clock_t jiffies_to_clock_t(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
- u64 tmp = (u64)x * TICK_NSEC;
- do_div(tmp, (NSEC_PER_SEC / USER_HZ));
- return (long)tmp;
+ return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
#endif
}
EXPORT_SYMBOL(jiffies_to_clock_t);
return ~0UL;
return x * (HZ / USER_HZ);
#else
- u64 jif;
-
/* Don't worry about loss of precision here .. */
if (x >= ~0UL / HZ * USER_HZ)
return ~0UL;
/* .. but do try to contain it here */
- jif = x * (u64) HZ;
- do_div(jif, USER_HZ);
- return jif;
+ return div_u64((u64)x * HZ, USER_HZ);
#endif
}
EXPORT_SYMBOL(clock_t_to_jiffies);
u64 jiffies_64_to_clock_t(u64 x)
{
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
- do_div(x, HZ / USER_HZ);
+# 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 *= TICK_NSEC;
- do_div(x, (NSEC_PER_SEC / USER_HZ));
+ x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
#endif
return x;
}
-
EXPORT_SYMBOL(jiffies_64_to_clock_t);
u64 nsec_to_clock_t(u64 x)
{
#if (NSEC_PER_SEC % USER_HZ) == 0
- do_div(x, (NSEC_PER_SEC / USER_HZ));
+ return div_u64(x, NSEC_PER_SEC / USER_HZ);
#elif (USER_HZ % 512) == 0
- x *= USER_HZ/512;
- do_div(x, (NSEC_PER_SEC / 512));
+ 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, ...
*/
- x *= 9;
- do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2)) /
- USER_HZ));
+ return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
#endif
- return x;
}
-#if (BITS_PER_LONG < 64)
-u64 get_jiffies_64(void)
+/**
+ * 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
+ */
+u64 nsecs_to_jiffies64(u64 n)
{
- unsigned long seq;
- u64 ret;
-
- do {
- seq = read_seqbegin(&xtime_lock);
- ret = jiffies_64;
- } while (read_seqretry(&xtime_lock, seq));
- return ret;
+#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(get_jiffies_64);
-#endif
+/**
+ * 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
+ */
+unsigned long nsecs_to_jiffies(u64 n)
+{
+ return (unsigned long)nsecs_to_jiffies64(n);
+}
+
+/*
+ * Add two timespec values and do a safety check for overflow.
+ * It's assumed that both values are valid (>= 0)
+ */
+struct timespec timespec_add_safe(const struct timespec lhs,
+ const struct timespec rhs)
+{
+ struct timespec res;
+
+ set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec,
+ lhs.tv_nsec + rhs.tv_nsec);
-EXPORT_SYMBOL(jiffies);
+ if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)
+ res.tv_sec = TIME_T_MAX;
+
+ return res;
+}
Code Review / linux-2.6.git / blobdiff