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vdso/vsyscall: Update auxiliary clock data in the datapage

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Expose the auxiliary clock data so it can be read from the vDSO.

Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-11-df7d9f87b9b8@linutronix.de
This commit is contained in:
Thomas Weißschuh 2025-07-01 10:58:05 +02:00 committed by Thomas Gleixner
parent 9b7fc3f145
commit 380b84e168
5 changed files with 66 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

6
include/linux/timekeeper_internal.h
View file

@ -190,4 +190,10 @@ static inline void update_vsyscall_tz(void)
}
#endif
#if defined(CONFIG_GENERIC_GETTIMEOFDAY) && defined(CONFIG_POSIX_AUX_CLOCKS)
extern void vdso_time_update_aux(struct timekeeper *tk);
#else
static inline void vdso_time_update_aux(struct timekeeper *tk) { }
#endif
#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */

3
include/vdso/datapage.h
View file

@ -38,6 +38,7 @@ struct vdso_arch_data {
#endif
#define VDSO_BASES (CLOCK_TAI + 1)
#define VDSO_BASE_AUX 0
#define VDSO_HRES (BIT(CLOCK_REALTIME) | \
BIT(CLOCK_MONOTONIC) | \
BIT(CLOCK_BOOTTIME) | \
@ -117,6 +118,7 @@ struct vdso_clock {
* @arch_data: architecture specific data (optional, defaults
* to an empty struct)
* @clock_data: clocksource related data (array)
* @aux_clock_data: auxiliary clocksource related data (array)
* @tz_minuteswest: minutes west of Greenwich
* @tz_dsttime: type of DST correction
* @hrtimer_res: hrtimer resolution
@ -133,6 +135,7 @@ struct vdso_time_data {
struct arch_vdso_time_data arch_data;
struct vdso_clock clock_data[CS_BASES];
struct vdso_clock aux_clock_data[MAX_AUX_CLOCKS];
s32 tz_minuteswest;
s32 tz_dsttime;

5
kernel/time/namespace.c
View file

@ -242,6 +242,11 @@ static void timens_set_vvar_page(struct task_struct *task,
for (i = 0; i < CS_BASES; i++)
timens_setup_vdso_clock_data(&vc[i], ns);
if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) {
for (i = 0; i < ARRAY_SIZE(vdata->aux_clock_data); i++)
timens_setup_vdso_clock_data(&vdata->aux_clock_data[i], ns);
}
out:
mutex_unlock(&offset_lock);
}

12
kernel/time/timekeeping.c
View file

@ -66,11 +66,21 @@ static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
{
return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts);
}
static inline bool tk_is_aux(const struct timekeeper *tk)
{
return tk->id >= TIMEKEEPER_AUX_FIRST && tk->id <= TIMEKEEPER_AUX_LAST;
}
#else
static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
{
return false;
}
static inline bool tk_is_aux(const struct timekeeper *tk)
{
return false;
}
#endif
/* flag for if timekeeping is suspended */
@ -719,6 +729,8 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act
update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
} else if (tk_is_aux(tk)) {
vdso_time_update_aux(tk);
}
if (action & TK_CLOCK_WAS_SET)

40
kernel/time/vsyscall.c
View file

@ -136,6 +136,46 @@ void update_vsyscall_tz(void)
__arch_sync_vdso_time_data(vdata);
}
#ifdef CONFIG_POSIX_AUX_CLOCKS
void vdso_time_update_aux(struct timekeeper *tk)
{
struct vdso_time_data *vdata = vdso_k_time_data;
struct vdso_timestamp *vdso_ts;
struct vdso_clock *vc;
s32 clock_mode;
u64 nsec;
vc = &vdata->aux_clock_data[tk->id - TIMEKEEPER_AUX_FIRST];
vdso_ts = &vc->basetime[VDSO_BASE_AUX];
clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
if (!tk->clock_valid)
clock_mode = VDSO_CLOCKMODE_NONE;
/* copy vsyscall data */
vdso_write_begin_clock(vc);
vc->clock_mode = clock_mode;
if (clock_mode != VDSO_CLOCKMODE_NONE) {
fill_clock_configuration(vc, &tk->tkr_mono);
vdso_ts->sec = tk->xtime_sec;
nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
nsec += tk->offs_aux;
vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
nsec = nsec << tk->tkr_mono.shift;
vdso_ts->nsec = nsec;
}
__arch_update_vdso_clock(vc);
vdso_write_end_clock(vc);
__arch_sync_vdso_time_data(vdata);
}
#endif
/**
* vdso_update_begin - Start of a VDSO update section
*