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vdso/gettimeofday: Prepare do_hres() for introduction of struct vdso_clock

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To support multiple PTP clocks, the VDSO data structure needs to be
reworked. All clock specific data will end up in struct vdso_clock and in
struct vdso_time_data there will be array of VDSO clocks. At the moment,
vdso_clock is simply a define which maps vdso_clock to vdso_time_data.

Prepare for the rework of these structures by adding a struct vdso_clock
pointer argument to do_hres(), and replace the struct vdso_time_data
pointer with the new pointer argument where applicable.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-7-c1b5c69a166f@linutronix.de
This commit is contained in:
Anna-Maria Behnsen
2025-03-03 12:11:09 +01:00
committed by Thomas Gleixner
parent cddb82d1c4
commit 64c3613ce3
1 changed files with 17 additions and 16 deletions
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33
lib/vdso/gettimeofday.c
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@@ -139,10 +139,11 @@ static __always_inline int do_hres_timens(const struct vdso_time_data *vdns, clo
}
#endif
static __always_inline int do_hres(const struct vdso_time_data *vd, clockid_t clk,
struct __kernel_timespec *ts)
static __always_inline
int do_hres(const struct vdso_time_data *vd, const struct vdso_clock *vc,
clockid_t clk, struct __kernel_timespec *ts)
{
const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
const struct vdso_timestamp *vdso_ts = &vc->basetime[clk];
u64 cycles, sec, ns;
u32 seq;
@@ -154,31 +155,31 @@ static __always_inline int do_hres(const struct vdso_time_data *vd, clockid_t cl
/*
* Open coded function vdso_read_begin() to handle
* VDSO_CLOCKMODE_TIMENS. Time namespace enabled tasks have a
* special VVAR page installed which has vd->seq set to 1 and
* vd->clock_mode set to VDSO_CLOCKMODE_TIMENS. For non time
* special VVAR page installed which has vc->seq set to 1 and
* vc->clock_mode set to VDSO_CLOCKMODE_TIMENS. For non time
* namespace affected tasks this does not affect performance
* because if vd->seq is odd, i.e. a concurrent update is in
* progress the extra check for vd->clock_mode is just a few
* extra instructions while spin waiting for vd->seq to become
* because if vc->seq is odd, i.e. a concurrent update is in
* progress the extra check for vc->clock_mode is just a few
* extra instructions while spin waiting for vc->seq to become
* even again.
*/
while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) {
while (unlikely((seq = READ_ONCE(vc->seq)) & 1)) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vc->clock_mode == VDSO_CLOCKMODE_TIMENS)
return do_hres_timens(vd, clk, ts);
cpu_relax();
}
smp_rmb();
if (unlikely(!vdso_clocksource_ok(vd)))
if (unlikely(!vdso_clocksource_ok(vc)))
return -1;
cycles = __arch_get_hw_counter(vd->clock_mode, vd);
cycles = __arch_get_hw_counter(vc->clock_mode, vd);
if (unlikely(!vdso_cycles_ok(cycles)))
return -1;
ns = vdso_calc_ns(vd, cycles, vdso_ts->nsec);
ns = vdso_calc_ns(vc, cycles, vdso_ts->nsec);
sec = vdso_ts->sec;
} while (unlikely(vdso_read_retry(vd, seq)));
} while (unlikely(vdso_read_retry(vc, seq)));
/*
* Do this outside the loop: a race inside the loop could result
@@ -278,7 +279,7 @@ __cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock,
else
return -1;
return do_hres(vc, clock, ts);
return do_hres(vd, vc, clock, ts);
}
static __maybe_unused int
@@ -334,7 +335,7 @@ __cvdso_gettimeofday_data(const struct vdso_time_data *vd,
if (likely(tv != NULL)) {
struct __kernel_timespec ts;
if (do_hres(&vc[CS_HRES_COARSE], CLOCK_REALTIME, &ts))
if (do_hres(vd, &vc[CS_HRES_COARSE], CLOCK_REALTIME, &ts))
return gettimeofday_fallback(tv, tz);
tv->tv_sec = ts.tv_sec;