unimore/kernel-hacking-2024-linux-steffo
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ntp: Rework do_adjtimex to take timespec and tai arguments

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In order to change the locking rules, we need to provide
the timespec and tai values rather then having the ntp
logic acquire these values itself.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz 2013-03-22 12:28:15 -07:00
parent e4085693f6
commit 87ace39b71
3 changed files with 17 additions and 16 deletions
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18
kernel/time/ntp.c
View file

@ -662,10 +662,8 @@ int ntp_validate_timex(struct timex *txc)
* adjtimex mainly allows reading (and writing, if superuser) of
* kernel time-keeping variables. used by xntpd.
*/
int __do_adjtimex(struct timex *txc)
int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai)
{
struct timespec ts;
u32 time_tai, orig_tai;
int result;
if (txc->modes & ADJ_SETOFFSET) {
@ -679,9 +677,6 @@ int __do_adjtimex(struct timex *txc)
return result;
}
getnstimeofday(&ts);
orig_tai = time_tai = timekeeping_get_tai_offset();
raw_spin_lock_irq(&ntp_lock);
if (txc->modes & ADJ_ADJTIME) {
@ -697,7 +692,7 @@ int __do_adjtimex(struct timex *txc)
/* If there are input parameters, then process them: */
if (txc->modes)
process_adjtimex_modes(txc, &ts, &time_tai);
process_adjtimex_modes(txc, ts, time_tai);
txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
NTP_SCALE_SHIFT);
@ -719,18 +714,15 @@ int __do_adjtimex(struct timex *txc)
txc->precision = 1;
txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
txc->tick = tick_usec;
txc->tai = time_tai;
txc->tai = *time_tai;
/* fill PPS status fields */
pps_fill_timex(txc);
raw_spin_unlock_irq(&ntp_lock);
if (time_tai != orig_tai)
timekeeping_set_tai_offset(time_tai);
txc->time.tv_sec = ts.tv_sec;
txc->time.tv_usec = ts.tv_nsec;
txc->time.tv_sec = ts->tv_sec;
txc->time.tv_usec = ts->tv_nsec;
if (!(time_status & STA_NANO))
txc->time.tv_usec /= NSEC_PER_USEC;

2
kernel/time/ntp_internal.h
View file

@ -7,6 +7,6 @@ extern void ntp_clear(void);
extern u64 ntp_tick_length(void);
extern int second_overflow(unsigned long secs);
extern int ntp_validate_timex(struct timex *);
extern int __do_adjtimex(struct timex *);
extern int __do_adjtimex(struct timex *, struct timespec *, s32 *);
extern void __hardpps(const struct timespec *, const struct timespec *);
#endif /* _LINUX_NTP_INTERNAL_H */

13
kernel/time/timekeeping.c
View file

@ -1618,6 +1618,8 @@ EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset);
*/
int do_adjtimex(struct timex *txc)
{
struct timespec ts;
s32 tai, orig_tai;
int ret;
/* Validate the data before disabling interrupts */
@ -1625,9 +1627,16 @@ int do_adjtimex(struct timex *txc)
if (ret)
return ret;
return __do_adjtimex(txc);
}
getnstimeofday(&ts);
orig_tai = tai = timekeeping_get_tai_offset();
ret = __do_adjtimex(txc, &ts, &tai);
if (tai != orig_tai)
timekeeping_set_tai_offset(tai);
return ret;
}
#ifdef CONFIG_NTP_PPS
/**