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vdso: Rework struct vdso_time_data and introduce 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 an array of VDSO clocks.

Now that all preparatory changes are in place:

Split the clock related struct members into a separate struct
vdso_clock. Make sure all users are aware, that vdso_time_data is no longer
initialized as an array and vdso_clock is now the array inside
vdso_data. Remove the vdso_clock define, which mapped it to vdso_time_data
for the transition.

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-v1-19-c1b5c69a166f@linutronix.de
This commit is contained in:
Anna-Maria Behnsen 2025-03-03 12:11:21 +01:00 committed by Thomas Gleixner
parent 97a5a90ca2
commit 886653e366
10 changed files with 57 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/include/asm/vdso/compat_gettimeofday.h
View File

@ -149,7 +149,7 @@ static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(
* where __aarch64_get_vdso_u_time_data() is called, and then keep the
* result in a register.
*/
asm volatile("mov %0, %1" : "=r"(ret) : "r"(vdso_u_time_data));
asm volatile("mov %0, %1" : "=r"(ret) : "r"(&vdso_u_time_data));
return ret;
}

4
arch/arm64/include/asm/vdso/vsyscall.h
View File

@ -15,8 +15,8 @@
static __always_inline
void __arm64_update_vsyscall(struct vdso_time_data *vdata)
{
vdata[CS_HRES_COARSE].mask = VDSO_PRECISION_MASK;
vdata[CS_RAW].mask = VDSO_PRECISION_MASK;
vdata->clock_data[CS_HRES_COARSE].mask = VDSO_PRECISION_MASK;
vdata->clock_data[CS_RAW].mask = VDSO_PRECISION_MASK;
}
#define __arch_update_vsyscall __arm64_update_vsyscall

11
arch/s390/kernel/time.c
View File

@ -79,12 +79,10 @@ void __init time_early_init(void)
{
struct ptff_qto qto;
struct ptff_qui qui;
int cs;
/* Initialize TOD steering parameters */
tod_steering_end = tod_clock_base.tod;
for (cs = 0; cs < CS_BASES; cs++)
vdso_k_time_data[cs].arch_data.tod_steering_end = tod_steering_end;
vdso_k_time_data->arch_data.tod_steering_end = tod_steering_end;
if (!test_facility(28))
return;
@ -373,7 +371,6 @@ static void clock_sync_global(long delta)
{
unsigned long now, adj;
struct ptff_qto qto;
int cs;
/* Fixup the monotonic sched clock. */
tod_clock_base.eitod += delta;
@ -389,10 +386,8 @@ static void clock_sync_global(long delta)
panic("TOD clock sync offset %li is too large to drift\n",
tod_steering_delta);
tod_steering_end = now + (abs(tod_steering_delta) << 15);
for (cs = 0; cs < CS_BASES; cs++) {
vdso_k_time_data[cs].arch_data.tod_steering_end = tod_steering_end;
vdso_k_time_data[cs].arch_data.tod_steering_delta = tod_steering_delta;
}
vdso_k_time_data->arch_data.tod_steering_end = tod_steering_end;
vdso_k_time_data->arch_data.tod_steering_delta = tod_steering_delta;
/* Update LPAR offset. */
if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)

2
include/asm-generic/vdso/vsyscall.h
View File

@ -9,7 +9,7 @@
#ifndef __arch_get_vdso_u_time_data
static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void)
{
return vdso_u_time_data;
return &vdso_u_time_data;
}
#endif

55
include/vdso/datapage.h
View File

@ -69,9 +69,7 @@ struct vdso_timestamp {
};
/**
* struct vdso_time_data - vdso datapage representation
* @arch_data: architecture specific data (optional, defaults
* to an empty struct)
* struct vdso_clock - vdso per clocksource datapage representation
* @seq: timebase sequence counter
* @clock_mode: clock mode
* @cycle_last: timebase at clocksource init
@ -81,17 +79,9 @@ struct vdso_timestamp {
* @shift: clocksource shift
* @basetime[clock_id]: basetime per clock_id
* @offset[clock_id]: time namespace offset per clock_id
* @tz_minuteswest: minutes west of Greenwich
* @tz_dsttime: type of DST correction
* @hrtimer_res: hrtimer resolution
* @__unused: unused
*
* vdso_time_data will be accessed by 64 bit and compat code at the same time
* so we should be careful before modifying this structure.
*
* The ordering of the struct members is optimized to have fast access to the
* often required struct members which are related to CLOCK_REALTIME and
* CLOCK_MONOTONIC. This information is stored in the first cache lines.
* See also struct vdso_time_data for basic access and ordering information as
* struct vdso_clock is used there.
*
* @basetime is used to store the base time for the system wide time getter
* VVAR page.
@ -104,9 +94,7 @@ struct vdso_timestamp {
* For clocks which are not affected by time namespace adjustment the
* offset must be zero.
*/
struct vdso_time_data {
struct arch_vdso_time_data arch_data;
struct vdso_clock {
u32 seq;
s32 clock_mode;
@ -122,15 +110,36 @@ struct vdso_time_data {
struct vdso_timestamp basetime[VDSO_BASES];
struct timens_offset offset[VDSO_BASES];
};
};
s32 tz_minuteswest;
s32 tz_dsttime;
u32 hrtimer_res;
u32 __unused;
/**
* struct vdso_time_data - vdso datapage representation
* @arch_data: architecture specific data (optional, defaults
* to an empty struct)
* @clock_data: clocksource related data (array)
* @tz_minuteswest: minutes west of Greenwich
* @tz_dsttime: type of DST correction
* @hrtimer_res: hrtimer resolution
* @__unused: unused
*
* vdso_time_data will be accessed by 64 bit and compat code at the same time
* so we should be careful before modifying this structure.
*
* The ordering of the struct members is optimized to have fast acces to the
* often required struct members which are related to CLOCK_REALTIME and
* CLOCK_MONOTONIC. This information is stored in the first cache lines.
*/
struct vdso_time_data {
struct arch_vdso_time_data arch_data;
struct vdso_clock clock_data[CS_BASES];
s32 tz_minuteswest;
s32 tz_dsttime;
u32 hrtimer_res;
u32 __unused;
} ____cacheline_aligned;
#define vdso_clock vdso_time_data
/**
* struct vdso_rng_data - vdso RNG state information
* @generation: counter representing the number of RNG reseeds
@ -151,7 +160,7 @@ struct vdso_rng_data {
* relocation, and this is what we need.
*/
#ifdef CONFIG_GENERIC_VDSO_DATA_STORE
extern struct vdso_time_data vdso_u_time_data[CS_BASES] __attribute__((visibility("hidden")));
extern struct vdso_time_data vdso_u_time_data __attribute__((visibility("hidden")));
extern struct vdso_rng_data vdso_u_rng_data __attribute__((visibility("hidden")));
extern struct vdso_arch_data vdso_u_arch_data __attribute__((visibility("hidden")));

4
include/vdso/helpers.h
View File

@ -30,7 +30,7 @@ static __always_inline u32 vdso_read_retry(const struct vdso_clock *vc,
static __always_inline void vdso_write_begin(struct vdso_time_data *vd)
{
struct vdso_clock *vc = vd;
struct vdso_clock *vc = vd->clock_data;
/*
* WRITE_ONCE() is required otherwise the compiler can validly tear
@ -44,7 +44,7 @@ static __always_inline void vdso_write_begin(struct vdso_time_data *vd)
static __always_inline void vdso_write_end(struct vdso_time_data *vd)
{
struct vdso_clock *vc = vd;
struct vdso_clock *vc = vd->clock_data;
smp_wmb();
/*

2
kernel/time/namespace.c
View File

@ -237,7 +237,7 @@ static void timens_set_vvar_page(struct task_struct *task,
ns->frozen_offsets = true;
vdata = page_address(ns->vvar_page);
vc = vdata;
vc = vdata->clock_data;
for (i = 0; i < CS_BASES; i++)
timens_setup_vdso_clock_data(&vc[i], ns);

11
kernel/time/vsyscall.c
View File

@ -17,8 +17,8 @@
static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct timekeeper *tk)
{
struct vdso_clock *vc = vdata->clock_data;
struct vdso_timestamp *vdso_ts;
struct vdso_clock *vc = vdata;
u64 nsec, sec;
vc[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
@ -78,8 +78,8 @@ static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct ti
void update_vsyscall(struct timekeeper *tk)
{
struct vdso_time_data *vdata = vdso_k_time_data;
struct vdso_clock *vc = vdata->clock_data;
struct vdso_timestamp *vdso_ts;
struct vdso_clock *vc = vdata;
s32 clock_mode;
u64 nsec;
@ -109,9 +109,8 @@ void update_vsyscall(struct timekeeper *tk)
/*
* Read without the seqlock held by clock_getres().
* Note: No need to have a second copy.
*/
WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
WRITE_ONCE(vdata->hrtimer_res, hrtimer_resolution);
/*
* If the current clocksource is not VDSO capable, then spare the
@ -131,8 +130,8 @@ void update_vsyscall_tz(void)
{
struct vdso_time_data *vdata = vdso_k_time_data;
vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
vdata->tz_minuteswest = sys_tz.tz_minuteswest;
vdata->tz_dsttime = sys_tz.tz_dsttime;
__arch_sync_vdso_time_data(vdata);
}

4
lib/vdso/datastore.c
View File

@ -13,10 +13,10 @@
*/
#ifdef CONFIG_HAVE_GENERIC_VDSO
static union {
struct vdso_time_data data[CS_BASES];
struct vdso_time_data data;
u8 page[PAGE_SIZE];
} vdso_time_data_store __page_aligned_data;
struct vdso_time_data *vdso_k_time_data = vdso_time_data_store.data;
struct vdso_time_data *vdso_k_time_data = &vdso_time_data_store.data;
static_assert(sizeof(vdso_time_data_store) == PAGE_SIZE);
#endif /* CONFIG_HAVE_GENERIC_VDSO */

16
lib/vdso/gettimeofday.c
View File

@ -87,8 +87,8 @@ int do_hres_timens(const struct vdso_time_data *vdns, const struct vdso_clock *v
{
const struct vdso_time_data *vd = __arch_get_vdso_u_timens_data(vdns);
const struct timens_offset *offs = &vcns->offset[clk];
const struct vdso_clock *vc = vd->clock_data;
const struct vdso_timestamp *vdso_ts;
const struct vdso_clock *vc = vd;
u64 cycles, ns;
u32 seq;
s64 sec;
@ -199,8 +199,8 @@ int do_coarse_timens(const struct vdso_time_data *vdns, const struct vdso_clock
{
const struct vdso_time_data *vd = __arch_get_vdso_u_timens_data(vdns);
const struct timens_offset *offs = &vcns->offset[clk];
const struct vdso_clock *vc = vd->clock_data;
const struct vdso_timestamp *vdso_ts;
const struct vdso_clock *vc = vd;
u64 nsec;
s64 sec;
s32 seq;
@ -265,7 +265,7 @@ static __always_inline int
__cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock,
struct __kernel_timespec *ts)
{
const struct vdso_clock *vc = vd;
const struct vdso_clock *vc = vd->clock_data;
u32 msk;
/* Check for negative values or invalid clocks */
@ -337,7 +337,7 @@ static __maybe_unused int
__cvdso_gettimeofday_data(const struct vdso_time_data *vd,
struct __kernel_old_timeval *tv, struct timezone *tz)
{
const struct vdso_clock *vc = vd;
const struct vdso_clock *vc = vd->clock_data;
if (likely(tv != NULL)) {
struct __kernel_timespec ts;
@ -371,13 +371,13 @@ __cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
static __maybe_unused __kernel_old_time_t
__cvdso_time_data(const struct vdso_time_data *vd, __kernel_old_time_t *time)
{
const struct vdso_clock *vc = vd;
const struct vdso_clock *vc = vd->clock_data;
__kernel_old_time_t t;
if (IS_ENABLED(CONFIG_TIME_NS) &&
vc->clock_mode == VDSO_CLOCKMODE_TIMENS) {
vd = __arch_get_vdso_u_timens_data(vd);
vc = vd;
vc = vd->clock_data;
}
t = READ_ONCE(vc[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
@ -399,7 +399,7 @@ static __maybe_unused
int __cvdso_clock_getres_common(const struct vdso_time_data *vd, clockid_t clock,
struct __kernel_timespec *res)
{
const struct vdso_clock *vc = vd;
const struct vdso_clock *vc = vd->clock_data;
u32 msk;
u64 ns;
@ -420,7 +420,7 @@ int __cvdso_clock_getres_common(const struct vdso_time_data *vd, clockid_t clock
/*
* Preserves the behaviour of posix_get_hrtimer_res().
*/
ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
ns = READ_ONCE(vd->hrtimer_res);
} else if (msk & VDSO_COARSE) {
/*
* Preserves the behaviour of posix_get_coarse_res().