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time: Provide y2038 safe do_settimeofday() replacement

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The kernel uses 32-bit signed value(time_t) for seconds elapsed
1970-01-01:00:00:00, thus it will overflow at 2038-01-19 03:14:08
on 32-bit systems. This is widely known as the y2038 problem.

As part of addressing "y2038 problem" for in-kernel uses, this patch
adds safe do_settimeofday64() using timespec64.

After this patch, do_settimeofday() is deprecated and all its call
sites will be fixed using do_settimeofday64(), after that it can be
removed.

Signed-off-by: pang.xunlei <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
pang.xunlei 2014-11-18 19:15:16 +08:00 committed by John Stultz
parent 659bc17b80
commit 21f7eca555
2 changed files with 29 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
include/linux/timekeeping.h
View File

@ -10,7 +10,7 @@ extern int timekeeping_suspended;
* Get and set timeofday
*/
extern void do_gettimeofday(struct timeval *tv);
extern int do_settimeofday(const struct timespec *tv);
extern int do_settimeofday64(const struct timespec64 *ts);
extern int do_sys_settimeofday(const struct timespec *tv,
const struct timezone *tz);
@ -33,6 +33,14 @@ extern int __getnstimeofday64(struct timespec64 *tv);
extern void getnstimeofday64(struct timespec64 *tv);
#if BITS_PER_LONG == 64
/**
* Deprecated. Use do_settimeofday64().
*/
static inline int do_settimeofday(const struct timespec *ts)
{
return do_settimeofday64(ts);
}
static inline int __getnstimeofday(struct timespec *ts)
{
return __getnstimeofday64(ts);
@ -54,6 +62,17 @@ static inline void ktime_get_real_ts(struct timespec *ts)
}
#else
/**
* Deprecated. Use do_settimeofday64().
*/
static inline int do_settimeofday(const struct timespec *ts)
{
struct timespec64 ts64;
ts64 = timespec_to_timespec64(*ts);
return do_settimeofday64(&ts64);
}
static inline int __getnstimeofday(struct timespec *ts)
{
struct timespec64 ts64;

19
kernel/time/timekeeping.c
View File

@ -703,18 +703,18 @@ void do_gettimeofday(struct timeval *tv)
EXPORT_SYMBOL(do_gettimeofday);
/**
* do_settimeofday - Sets the time of day
* @tv: pointer to the timespec variable containing the new time
* do_settimeofday64 - Sets the time of day.
* @ts: pointer to the timespec64 variable containing the new time
*
* Sets the time of day to the new time and update NTP and notify hrtimers
*/
int do_settimeofday(const struct timespec *tv)
int do_settimeofday64(const struct timespec64 *ts)
{
struct timekeeper *tk = &tk_core.timekeeper;
struct timespec64 ts_delta, xt, tmp;
struct timespec64 ts_delta, xt;
unsigned long flags;
if (!timespec_valid_strict(tv))
if (!timespec64_valid_strict(ts))
return -EINVAL;
raw_spin_lock_irqsave(&timekeeper_lock, flags);
@ -723,13 +723,12 @@ int do_settimeofday(const struct timespec *tv)
timekeeping_forward_now(tk);
xt = tk_xtime(tk);
ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
tmp = timespec_to_timespec64(*tv);
tk_set_xtime(tk, &tmp);
tk_set_xtime(tk, ts);
timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
@ -741,7 +740,7 @@ int do_settimeofday(const struct timespec *tv)
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
EXPORT_SYMBOL(do_settimeofday64);
/**
* timekeeping_inject_offset - Adds or subtracts from the current time.