/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
* Copyright (c) 2021 Dmitry Chagin <dchagin@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
static int
fls(int mask)
{
if (mask == 0)
return (0);
return ((__builtin_clz(mask) ^ 0x1f) + 1);
}
#ifdef _LP64
static int
ffsl(long mask)
{
int bit;
if (mask == 0)
return (0);
for (bit = 1; !(mask & 1); bit++)
mask = (unsigned long)mask >> 1;
return (bit);
}
#else
static int
ffsll(long long mask)
{
int bit;
if (mask == 0)
return (0);
for (bit = 1; !(mask & 1); bit++)
mask = (unsigned long long)mask >> 1;
return (bit);
}
#endif
static int
__vdso_native_to_linux_timespec(struct l_timespec *lts,
struct timespec *nts)
{
#ifdef COMPAT_LINUX32
if (nts->tv_sec > INT_MAX || nts->tv_sec < INT_MIN)
return (LINUX_EOVERFLOW);
#endif
lts->tv_sec = nts->tv_sec;
lts->tv_nsec = nts->tv_nsec;
return (0);
}
static int
__vdso_native_to_linux_timeval(l_timeval *ltv,
struct timeval *ntv)
{
#ifdef COMPAT_LINUX32
if (ntv->tv_sec > INT_MAX || ntv->tv_sec < INT_MIN)
return (LINUX_EOVERFLOW);
#endif
ltv->tv_sec = ntv->tv_sec;
ltv->tv_usec = ntv->tv_usec;
return (0);
}
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
static int
__vdso_native_to_linux_timespec64(struct l_timespec64 *lts,
struct timespec *nts)
{
lts->tv_sec = nts->tv_sec;
lts->tv_nsec = nts->tv_nsec;
return (0);
}
#endif
static int
__vdso_linux_to_native_clockid(clockid_t *n, clockid_t l)
{
switch (l) {
case LINUX_CLOCK_REALTIME:
*n = CLOCK_REALTIME;
break;
case LINUX_CLOCK_MONOTONIC:
*n = CLOCK_MONOTONIC;
break;
case LINUX_CLOCK_REALTIME_COARSE:
*n = CLOCK_REALTIME_FAST;
break;
case LINUX_CLOCK_MONOTONIC_COARSE:
case LINUX_CLOCK_MONOTONIC_RAW:
*n = CLOCK_MONOTONIC_FAST;
break;
case LINUX_CLOCK_BOOTTIME:
*n = CLOCK_UPTIME;
break;
default:
return (LINUX_EINVAL);
}
return (0);
}
/*
* The code below adapted from
* lib/libc/sys/__vdso_gettimeofday.c
*/
static inline void
__vdso_gettimekeep(struct vdso_timekeep **tk)
{
*tk = (struct vdso_timekeep *)kern_timekeep_base;
}
static int
tc_delta(const struct vdso_timehands *th, u_int *delta)
{
int error;
u_int tc;
error = __vdso_gettc(th, &tc);
if (error == 0)
*delta = (tc - th->th_offset_count) & th->th_counter_mask;
return (error);
}
/*
* Calculate the absolute or boot-relative time from the
* machine-specific fast timecounter and the published timehands
* structure read from the shared page.
*
* The lockless reading scheme is similar to the one used to read the
* in-kernel timehands, see sys/kern/kern_tc.c:binuptime(). This code
* is based on the kernel implementation.
*/
static int
freebsd_binuptime(struct bintime *bt, struct vdso_timekeep *tk, bool abs)
{
struct vdso_timehands *th;
uint32_t curr, gen;
uint64_t scale, x;
u_int delta, scale_bits;
int error;
do {
if (!tk->tk_enabled)
return (ENOSYS);
curr = atomic_load_acq_32(&tk->tk_current);
th = &tk->tk_th[curr];
gen = atomic_load_acq_32(&th->th_gen);
*bt = th->th_offset;
error = tc_delta(th, &delta);
if (error == EAGAIN)
continue;
if (error != 0)
return (error);
scale = th->th_scale;
#ifdef _LP64
scale_bits = ffsl(scale);
#else
scale_bits = ffsll(scale);
#endif
if (__predict_false(scale_bits + fls(delta) > 63)) {
x = (scale >> 32) * delta;
scale &= 0xffffffff;
bt->sec += x >> 32;
bintime_addx(bt, x << 32);
}
bintime_addx(bt, scale * delta);
if (abs)
bintime_add(bt, &th->th_boottime);
/*
* Ensure that the load of th_offset is completed
* before the load of th_gen.
*/
atomic_thread_fence_acq();
} while (curr != tk->tk_current || gen == 0 || gen != th->th_gen);
return (0);
}
static int
freebsd_getnanouptime(struct bintime *bt, struct vdso_timekeep *tk)
{
struct vdso_timehands *th;
uint32_t curr, gen;
do {
if (!tk->tk_enabled)
return (ENOSYS);
curr = atomic_load_acq_32(&tk->tk_current);
th = &tk->tk_th[curr];
gen = atomic_load_acq_32(&th->th_gen);
*bt = th->th_offset;
/*
* Ensure that the load of th_offset is completed
* before the load of th_gen.
*/
atomic_thread_fence_acq();
} while (curr != tk->tk_current || gen == 0 || gen != th->th_gen);
return (0);
}
static int
freebsd_gettimeofday(struct timeval *tv, struct timezone *tz)
{
struct vdso_timekeep *tk;
struct bintime bt;
int error;
if (tz != NULL)
return (ENOSYS);
__vdso_gettimekeep(&tk);
if (tk == NULL)
return (ENOSYS);
if (tk->tk_ver != VDSO_TK_VER_CURR)
return (ENOSYS);
error = freebsd_binuptime(&bt, tk, true);
if (error == 0)
bintime2timeval(&bt, tv);
return (error);
}
static int
freebsd_clock_gettime(clockid_t clock_id, struct timespec *ts)
{
struct vdso_timekeep *tk;
struct bintime bt;
int error;
__vdso_gettimekeep(&tk);
if (tk == NULL)
return (ENOSYS);
if (tk->tk_ver != VDSO_TK_VER_CURR)
return (ENOSYS);
switch (clock_id) {
case CLOCK_REALTIME:
case CLOCK_REALTIME_PRECISE:
case CLOCK_REALTIME_FAST:
error = freebsd_binuptime(&bt, tk, true);
break;
case CLOCK_MONOTONIC:
case CLOCK_MONOTONIC_PRECISE:
case CLOCK_UPTIME:
case CLOCK_UPTIME_PRECISE:
error = freebsd_binuptime(&bt, tk, false);
break;
case CLOCK_MONOTONIC_FAST:
case CLOCK_UPTIME_FAST:
error = freebsd_getnanouptime(&bt, tk);
break;
default:
error = ENOSYS;
break;
}
if (error == 0)
bintime2timespec(&bt, ts);
return (error);
}
/*
* Linux vDSO interfaces
*
*/
int
__vdso_clock_gettime(clockid_t clock_id, struct l_timespec *lts)
{
struct timespec ts;
clockid_t which;
int error;
error = __vdso_linux_to_native_clockid(&which, clock_id);
if (error != 0)
return (__vdso_clock_gettime_fallback(clock_id, lts));
error = freebsd_clock_gettime(which, &ts);
if (error == 0)
return (-__vdso_native_to_linux_timespec(lts, &ts));
else
return (__vdso_clock_gettime_fallback(clock_id, lts));
}
int
__vdso_gettimeofday(l_timeval *ltv, struct timezone *tz)
{
struct timeval tv;
int error;
error = freebsd_gettimeofday(&tv, tz);
if (error != 0)
return (__vdso_gettimeofday_fallback(ltv, tz));
return (-__vdso_native_to_linux_timeval(ltv, &tv));
}
int
__vdso_clock_getres(clockid_t clock_id, struct l_timespec *lts)
{
return (__vdso_clock_getres_fallback(clock_id, lts));
}
#if defined(__i386__) || defined(COMPAT_LINUX32)
int
__vdso_clock_gettime64(clockid_t clock_id, struct l_timespec64 *lts)
{
struct timespec ts;
clockid_t which;
int error;
error = __vdso_linux_to_native_clockid(&which, clock_id);
if (error != 0)
return (__vdso_clock_gettime64_fallback(clock_id, lts));
error = freebsd_clock_gettime(which, &ts);
if (error == 0)
return(-__vdso_native_to_linux_timespec64(lts, &ts));
else
return(__vdso_clock_gettime64_fallback(clock_id, lts));
}
int clock_gettime64(clockid_t clock_id, struct l_timespec64 *lts)
__attribute__((weak, alias("__vdso_clock_gettime64")));
#endif
#if defined(__amd64__) && !defined(COMPAT_LINUX32)
int
__vdso_getcpu(uint32_t *cpu, uint32_t *node, void *cache)
{
return (__vdso_getcpu_fallback(cpu, node, cache));
}
#endif
#if defined(__i386__) || defined(__amd64__)
int
__vdso_time(long *tm)
{
return (__vdso_time_fallback(tm));
}
#endif
