// SPDX-License-Identifier: GPL-2.0
/*
* Generic userspace implementations of gettimeofday() and similar.
*/
#include <vdso/datapage.h>
#include <vdso/helpers.h>
#ifndef vdso_calc_delta
/*
* Default implementation which works for all sane clocksources. That
* obviously excludes x86/TSC.
*/
static __always_inline
u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
{
return ((cycles - last) & mask) * mult;
}
#endif
#ifndef vdso_shift_ns
static __always_inline u64 vdso_shift_ns(u64 ns, u32 shift)
{
return ns >> shift;
}
#endif
#ifndef __arch_vdso_hres_capable
static inline bool __arch_vdso_hres_capable(void)
{
return true;
}
#endif
#ifndef vdso_clocksource_ok
static inline bool vdso_clocksource_ok(const struct vdso_data *vd)
{
return vd->clock_mode != VDSO_CLOCKMODE_NONE;
}
#endif
#ifndef vdso_cycles_ok
static inline bool vdso_cycles_ok(u64 cycles)
{
return true;
}
#endif
#ifdef CONFIG_TIME_NS
static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_t clk,
struct __kernel_timespec *ts)
{
const struct vdso_data *vd;
const struct timens_offset *offs = &vdns->offset[clk];
const struct vdso_timestamp *vdso_ts;
u64 cycles, last, ns;
u32 seq;
s64 sec;
vd = vdns - (clk == CLOCK_MONOTONIC_RAW ? CS_RAW : CS_HRES_COARSE);
vd = __arch_get_timens_vdso_data(vd);
if (clk != CLOCK_MONOTONIC_RAW)
vd = &vd[CS_HRES_COARSE];
else
vd = &vd[CS_RAW];
vdso_ts = &vd->basetime[clk];
do {
seq = vdso_read_begin(vd);
if (unlikely(!vdso_clocksource_ok(vd)))
return -1;
cycles = __arch_get_hw_counter(vd->clock_mode, vd);
if (unlikely(!vdso_cycles_ok(cycles)))
return -1;
ns = vdso_ts->nsec;
last = vd->cycle_last;
ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
ns = vdso_shift_ns(ns, vd->shift);
sec = vdso_ts->sec;
} while (unlikely(vdso_read_retry(vd, seq)));
/* Add the namespace offset */
sec += offs->sec;
ns += offs->nsec;
/*
* Do this outside the loop: a race inside the loop could result
* in __iter_div_u64_rem() being extremely slow.
*/
ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
ts->tv_nsec = ns;
return 0;
}
#else
static __always_inline
const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
{
return NULL;
}
static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_t clk,
struct __kernel_timespec *ts)
{
return -EINVAL;
}
#endif
static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
struct __kernel_timespec *ts)
{
const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
u64 cycles, last, sec, ns;
u32 seq;
/* Allows to compile the high resolution parts out */
if (!__arch_vdso_hres_capable())
return -1;
do {
/*
* Open coded 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 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
* even again.
*/
while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
return do_hres_timens(vd, clk, ts);
cpu_relax();
}
smp_rmb();
if (unlikely(!vdso_clocksource_ok(vd)))
return -1;
cycles = __arch_get_hw_counter(vd->clock_mode, vd);
if (unlikely(!vdso_cycles_ok(cycles)))
return -1;
ns = vdso_ts->nsec;
last = vd->cycle_last;
ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
ns = vdso_shift_ns(ns, vd->shift);
sec = vdso_ts->sec;
} while (unlikely(vdso_read_retry(vd, seq)));
/*
* Do this outside the loop: a race inside the loop could result
* in __iter_div_u64_rem() being extremely slow.
*/
ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
ts->tv_nsec = ns;
return 0;
}
#ifdef CONFIG_TIME_NS
static __always_inline int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk,
struct __kernel_timespec *ts)
{
const struct vdso_data *vd = __arch_get_timens_vdso_data(vdns);
const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
const struct timens_offset *offs = &vdns->offset[clk];
u64 nsec;
s64 sec;
s32 seq;
do {
seq = vdso_read_begin(vd);
sec = vdso_ts->sec;
nsec = vdso_ts->nsec;
} while (unlikely(vdso_read_retry(vd, seq)));
/* Add the namespace offset */
sec += offs->sec;
nsec += offs->nsec;
/*
* Do this outside the loop: a race inside the loop could result
* in __iter_div_u64_rem() being extremely slow.
*/
ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
ts->tv_nsec = nsec;
return 0;
}
#else
static __always_inline int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk,
struct __kernel_timespec *ts)
{
return -1;
}
#endif
static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk,
struct __kernel_timespec *ts)
{
const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
u32 seq;
do {
/*
* Open coded to handle VDSO_CLOCK_TIMENS. See comment in
* do_hres().
*/
while ((seq = READ_ONCE(vd->seq)) & 1) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
return do_coarse_timens(vd, clk, ts);
cpu_relax();
}
smp_rmb();
ts->tv_sec = vdso_ts->sec;
ts->tv_nsec = vdso_ts->nsec;
} while (unlikely(vdso_read_retry(vd, seq)));
return 0;
}
static __always_inline int
__cvdso_clock_gettime_common(const struct vdso_data *vd, clockid_t clock,
struct __kernel_timespec *ts)
{
u32 msk;
/* Check for negative values or invalid clocks */
if (unlikely((u32) clock >= MAX_CLOCKS))
return -1;
/*
* Convert the clockid to a bitmask and use it to check which
* clocks are handled in the VDSO directly.
*/
msk = 1U << clock;
if (likely(msk & VDSO_HRES))
vd = &vd[CS_HRES_COARSE];
else if (msk & VDSO_COARSE)
return do_coarse(&vd[CS_HRES_COARSE], clock, ts);
else if (msk & VDSO_RAW)
vd = &vd[CS_RAW];
else
return -1;
return do_hres(vd, clock, ts);
}
static __maybe_unused int
__cvdso_clock_gettime_data(const struct vdso_data *vd, clockid_t clock,
struct __kernel_timespec *ts)
{
int ret = __cvdso_clock_gettime_common(vd, clock, ts);
if (unlikely(ret))
return clock_gettime_fallback(clock, ts);
return 0;
}
static __maybe_unused int
__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
{
return __cvdso_clock_gettime_data(__arch_get_vdso_data(), clock, ts);
}
#ifdef BUILD_VDSO32
static __maybe_unused int
__cvdso_clock_gettime32_data(const struct vdso_data *vd, clockid_t clock,
struct old_timespec32 *res)
{
struct __kernel_timespec ts;
int ret;
ret = __cvdso_clock_gettime_common(vd, clock, &ts);
if (unlikely(ret))
return clock_gettime32_fallback(clock, res);
/* For ret == 0 */
res->tv_sec = ts.tv_sec;
res->tv_nsec = ts.tv_nsec;
return ret;
}
static __maybe_unused int
__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
{
return __cvdso_clock_gettime32_data(__arch_get_vdso_data(), clock, res);
}
#endif /* BUILD_VDSO32 */
static __maybe_unused int
__cvdso_gettimeofday_data(const struct vdso_data *vd,
struct __kernel_old_timeval *tv, struct timezone *tz)
{
if (likely(tv != NULL)) {
struct __kernel_timespec ts;
if (do_hres(&vd[CS_HRES_COARSE], CLOCK_REALTIME, &ts))
return gettimeofday_fallback(tv, tz);
tv->tv_sec = ts.tv_sec;
tv->tv_usec = (u32)ts.tv_nsec / NSEC_PER_USEC;
}
if (unlikely(tz != NULL)) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vd = __arch_get_timens_vdso_data(vd);
tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
tz->tz_dsttime = vd[CS_HRES_COARSE].tz_dsttime;
}
return 0;
}
static __maybe_unused int
__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
{
return __cvdso_gettimeofday_data(__arch_get_vdso_data(), tv, tz);
}
#ifdef VDSO_HAS_TIME
static __maybe_unused __kernel_old_time_t
__cvdso_time_data(const struct vdso_data *vd, __kernel_old_time_t *time)
{
__kernel_old_time_t t;
if (IS_ENABLED(CONFIG_TIME_NS) &&
vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vd = __arch_get_timens_vdso_data(vd);
t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
if (time)
*time = t;
return t;
}
static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)
{
return __cvdso_time_data(__arch_get_vdso_data(), time);
}
#endif /* VDSO_HAS_TIME */
#ifdef VDSO_HAS_CLOCK_GETRES
static __maybe_unused
int __cvdso_clock_getres_common(const struct vdso_data *vd, clockid_t clock,
struct __kernel_timespec *res)
{
u32 msk;
u64 ns;
/* Check for negative values or invalid clocks */
if (unlikely((u32) clock >= MAX_CLOCKS))
return -1;
if (IS_ENABLED(CONFIG_TIME_NS) &&
vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vd = __arch_get_timens_vdso_data(vd);
/*
* Convert the clockid to a bitmask and use it to check which
* clocks are handled in the VDSO directly.
*/
msk = 1U << clock;
if (msk & (VDSO_HRES | VDSO_RAW)) {
/*
* Preserves the behaviour of posix_get_hrtimer_res().
*/
ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
} else if (msk & VDSO_COARSE) {
/*
* Preserves the behaviour of posix_get_coarse_res().
*/
ns = LOW_RES_NSEC;
} else {
return -1;
}
if (likely(res)) {
res->tv_sec = 0;
res->tv_nsec = ns;
}
return 0;
}
static __maybe_unused
int __cvdso_clock_getres_data(const struct vdso_data *vd, clockid_t clock,
struct __kernel_timespec *res)
{
int ret = __cvdso_clock_getres_common(vd, clock, res);
if (unlikely(ret))
return clock_getres_fallback(clock, res);
return 0;
}
static __maybe_unused
int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
{
return __cvdso_clock_getres_data(__arch_get_vdso_data(), clock, res);
}
#ifdef BUILD_VDSO32
static __maybe_unused int
__cvdso_clock_getres_time32_data(const struct vdso_data *vd, clockid_t clock,
struct old_timespec32 *res)
{
struct __kernel_timespec ts;
int ret;
ret = __cvdso_clock_getres_common(vd, clock, &ts);
if (unlikely(ret))
return clock_getres32_fallback(clock, res);
if (likely(res)) {
res->tv_sec = ts.tv_sec;
res->tv_nsec = ts.tv_nsec;
}
return ret;
}
static __maybe_unused int
__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
{
return __cvdso_clock_getres_time32_data(__arch_get_vdso_data(),
clock, res);
}
#endif /* BUILD_VDSO32 */
#endif /* VDSO_HAS_CLOCK_GETRES */
