linux/lib/vdso/gettimeofday.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Generic userspace implementations of gettimeofday() and similar.
 */
#include <vdso/datapage.h>
#include <vdso/helpers.h>

#ifndef vdso_calc_ns

#ifdef VDSO_DELTA_NOMASK
#define VDSO_DELTA_MASK …
#else
#define VDSO_DELTA_MASK …
#endif

#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
static __always_inline bool vdso_delta_ok(const struct vdso_data *vd, u64 delta)
{
	return delta < vd->max_cycles;
}
#else
static __always_inline bool vdso_delta_ok(const struct vdso_data *vd, u64 delta)
{
	return true;
}
#endif

#ifndef vdso_shift_ns
static __always_inline u64 vdso_shift_ns(u64 ns, u32 shift)
{
	return ns >> shift;
}
#endif

/*
 * Default implementation which works for all sane clocksources. That
 * obviously excludes x86/TSC.
 */
static __always_inline u64 vdso_calc_ns(const struct vdso_data *vd, u64 cycles, u64 base)
{
	u64 delta = (cycles - vd->cycle_last) & VDSO_DELTA_MASK(vd);

	if (likely(vdso_delta_ok(vd, delta)))
		return vdso_shift_ns((delta * vd->mult) + base, vd->shift);

	return mul_u64_u32_add_u64_shr(delta, vd->mult, base, vd->shift);
}
#endif /* vdso_calc_ns */

#ifndef __arch_vdso_hres_capable
static inline bool __arch_vdso_hres_capable(void)
{ … }
#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)
{ … }
#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)
{ … }

#ifdef CONFIG_TIME_NS
static __always_inline int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk,
					    struct __kernel_timespec *ts)
{ … }
#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)
{ … }

static __always_inline int
__cvdso_clock_gettime_common(const struct vdso_data *vd, clockid_t clock,
			     struct __kernel_timespec *ts)
{ … }

static __maybe_unused int
__cvdso_clock_gettime_data(const struct vdso_data *vd, clockid_t clock,
			   struct __kernel_timespec *ts)
{ … }

static __maybe_unused int
__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *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)
{ … }

static __maybe_unused int
__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *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)
{ … }

static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *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)
{ … }

static __maybe_unused
int __cvdso_clock_getres_data(const struct vdso_data *vd, clockid_t clock,
			      struct __kernel_timespec *res)
{ … }

static __maybe_unused
int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *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 */