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-rw-r--r--kernel/time.c221
1 files changed, 130 insertions, 91 deletions
diff --git a/kernel/time.c b/kernel/time.c
index a5ec013b6c8..7c7964c33ae 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -11,7 +11,7 @@
* 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/core.c and adjtimex()
* 1993-10-08 Torsten Duwe
* adjtime interface update and CMOS clock write code
* 1995-08-13 Torsten Duwe
@@ -27,14 +27,16 @@
* with nanosecond accuracy
*/
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/timex.h>
#include <linux/capability.h>
-#include <linux/clocksource.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 <asm/uaccess.h>
#include <asm/unistd.h>
@@ -57,14 +59,15 @@ EXPORT_SYMBOL(sys_tz);
* 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 = get_seconds();
if (tloc) {
if (put_user(i,tloc))
- i = -EFAULT;
+ return -EFAULT;
}
+ force_successful_syscall_return();
return i;
}
@@ -75,7 +78,7 @@ asmlinkage long sys_time(time_t __user * tloc)
* architectures that need it).
*/
-asmlinkage long sys_stime(time_t __user *tptr)
+SYSCALL_DEFINE1(stime, time_t __user *, tptr)
{
struct timespec tv;
int err;
@@ -95,8 +98,8 @@ asmlinkage long sys_stime(time_t __user *tptr)
#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;
@@ -112,6 +115,12 @@ asmlinkage long sys_gettimeofday(struct timeval __user *tv,
}
/*
+ * Indicates if there is an offset between the system clock and the hardware
+ * clock/persistent clock/rtc.
+ */
+int persistent_clock_is_local;
+
+/*
* Adjust the time obtained from the CMOS to be UTC time instead of
* local time.
*
@@ -129,12 +138,14 @@ asmlinkage long sys_gettimeofday(struct timeval __user *tv,
*/
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;
- update_xtime_cache(0);
- write_sequnlock_irq(&xtime_lock);
- clock_was_set();
+ if (sys_tz.tz_minuteswest != 0) {
+ struct timespec adjust;
+
+ persistent_clock_is_local = 1;
+ adjust.tv_sec = sys_tz.tz_minuteswest * 60;
+ adjust.tv_nsec = 0;
+ timekeeping_inject_offset(&adjust);
+ }
}
/*
@@ -148,7 +159,7 @@ static inline void warp_clock(void)
* 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;
@@ -161,7 +172,6 @@ int do_sys_settimeofday(struct timespec *tv, struct timezone *tz)
return error;
if (tz) {
- /* SMP safe, global irq locking makes it work. */
sys_tz = *tz;
update_vsyscall_tz();
if (firsttime) {
@@ -171,17 +181,12 @@ int do_sys_settimeofday(struct timespec *tv, struct timezone *tz)
}
}
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)
+SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
+ struct timezone __user *, tz)
{
struct timeval user_tv;
struct timespec new_ts;
@@ -201,7 +206,7 @@ asmlinkage long sys_settimeofday(struct timeval __user *tv,
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;
@@ -236,7 +241,7 @@ EXPORT_SYMBOL(current_fs_time);
* Avoid unnecessary multiplications/divisions in the
* two most common HZ cases:
*/
-unsigned int inline jiffies_to_msecs(const unsigned long j)
+unsigned int jiffies_to_msecs(const unsigned long j)
{
#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
return (MSEC_PER_SEC / HZ) * j;
@@ -244,7 +249,7 @@ unsigned int inline jiffies_to_msecs(const unsigned long j)
return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
#else
# if BITS_PER_LONG == 32
- return ((u64)HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
+ return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
# else
return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
# endif
@@ -252,7 +257,7 @@ unsigned int inline jiffies_to_msecs(const unsigned long j)
}
EXPORT_SYMBOL(jiffies_to_msecs);
-unsigned int inline jiffies_to_usecs(const unsigned long j)
+unsigned int jiffies_to_usecs(const unsigned long j)
{
#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
return (USEC_PER_SEC / HZ) * j;
@@ -260,7 +265,7 @@ unsigned int inline jiffies_to_usecs(const unsigned long j)
return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
#else
# if BITS_PER_LONG == 32
- return ((u64)HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
+ return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
# else
return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
# endif
@@ -298,22 +303,6 @@ struct timespec timespec_trunc(struct timespec t, unsigned gran)
}
EXPORT_SYMBOL(timespec_trunc);
-#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
-
/* 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.
@@ -366,19 +355,27 @@ EXPORT_SYMBOL(mktime);
* 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
@@ -389,13 +386,17 @@ void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec)
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;
}
@@ -469,7 +470,7 @@ unsigned long msecs_to_jiffies(const unsigned int m)
if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
return MAX_JIFFY_OFFSET;
- return ((u64)MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
+ return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
>> MSEC_TO_HZ_SHR32;
#endif
}
@@ -484,7 +485,7 @@ unsigned long usecs_to_jiffies(const unsigned int u)
#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
return u * (HZ / USEC_PER_SEC);
#else
- return ((u64)USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
+ return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
>> USEC_TO_HZ_SHR32;
#endif
}
@@ -525,8 +526,10 @@ jiffies_to_timespec(const unsigned long jiffies, struct timespec *value)
* 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);
@@ -564,19 +567,18 @@ void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
* 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);
/*
* Convert jiffies/jiffies_64 to clock_t and back.
*/
-clock_t jiffies_to_clock_t(long x)
+clock_t jiffies_to_clock_t(unsigned long x)
{
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
# if HZ < USER_HZ
@@ -585,9 +587,7 @@ clock_t jiffies_to_clock_t(long x)
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);
@@ -599,16 +599,12 @@ unsigned long clock_t_to_jiffies(unsigned long x)
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);
@@ -617,10 +613,9 @@ u64 jiffies_64_to_clock_t(u64 x)
{
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
# if HZ < USER_HZ
- x *= USER_HZ;
- do_div(x, HZ);
+ x = div_u64(x * USER_HZ, HZ);
# elif HZ > USER_HZ
- do_div(x, HZ / USER_HZ);
+ x = div_u64(x, HZ / USER_HZ);
# else
/* Nothing to do */
# endif
@@ -630,8 +625,7 @@ u64 jiffies_64_to_clock_t(u64 x)
* 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;
}
@@ -640,36 +634,81 @@ 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
+}
+
+/**
+ * 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)
+{
+#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
- return x;
}
-#if (BITS_PER_LONG < 64)
-u64 get_jiffies_64(void)
+/**
+ * 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)
{
- unsigned long seq;
- u64 ret;
-
- do {
- seq = read_seqbegin(&xtime_lock);
- ret = jiffies_64;
- } while (read_seqretry(&xtime_lock, seq));
- return ret;
+ return (unsigned long)nsecs_to_jiffies64(n);
}
-EXPORT_SYMBOL(get_jiffies_64);
-#endif
-EXPORT_SYMBOL(jiffies);
+/*
+ * 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);
+
+ if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)
+ res.tv_sec = TIME_T_MAX;
+
+ return res;
+}
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