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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 ARM Ltd.
*
* Generic implementation of update_vsyscall and update_vsyscall_tz.
*
* Based on the x86 specific implementation.
*/
#include <linux/hrtimer.h>
#include <linux/timekeeper_internal.h>
#include <vdso/datapage.h>
#include <vdso/helpers.h>
#include <vdso/vsyscall.h>
#include "timekeeping_internal.h"
static inline void update_vdso_data(struct vdso_data *vdata,
struct timekeeper *tk)
{
struct vdso_timestamp *vdso_ts;
u64 nsec, sec;
vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask;
vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult;
vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift;
vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last;
vdata[CS_RAW].mask = tk->tkr_raw.mask;
vdata[CS_RAW].mult = tk->tkr_raw.mult;
vdata[CS_RAW].shift = tk->tkr_raw.shift;
/* CLOCK_MONOTONIC */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
nsec = tk->tkr_mono.xtime_nsec;
nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
vdso_ts->sec++;
}
vdso_ts->nsec = nsec;
/* Copy MONOTONIC time for BOOTTIME */
sec = vdso_ts->sec;
/* Add the boot offset */
sec += tk->monotonic_to_boot.tv_sec;
nsec += (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift;
/* CLOCK_BOOTTIME */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
vdso_ts->sec = sec;
while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
vdso_ts->sec++;
}
vdso_ts->nsec = nsec;
/* CLOCK_MONOTONIC_RAW */
vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
vdso_ts->sec = tk->raw_sec;
vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
/* CLOCK_TAI */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;
vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
}
void update_vsyscall(struct timekeeper *tk)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
struct vdso_timestamp *vdso_ts;
s32 clock_mode;
u64 nsec;
/* copy vsyscall data */
vdso_write_begin(vdata);
clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
vdata[CS_HRES_COARSE].clock_mode = clock_mode;
vdata[CS_RAW].clock_mode = clock_mode;
/* CLOCK_REALTIME also required for time() */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
vdso_ts->sec = tk->xtime_sec;
vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
/* CLOCK_REALTIME_COARSE */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
vdso_ts->sec = tk->xtime_sec;
vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
/* CLOCK_MONOTONIC_COARSE */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
nsec = nsec + tk->wall_to_monotonic.tv_nsec;
vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
/*
* 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);
/*
* If the current clocksource is not VDSO capable, then spare the
* update of the high resolution parts.
*/
if (clock_mode != VDSO_CLOCKMODE_NONE)
update_vdso_data(vdata, tk);
__arch_update_vsyscall(vdata, tk);
vdso_write_end(vdata);
__arch_sync_vdso_data(vdata);
}
void update_vsyscall_tz(void)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
__arch_sync_vdso_data(vdata);
}
/**
* vdso_update_begin - Start of a VDSO update section
*
* Allows architecture code to safely update the architecture specific VDSO
* data. Disables interrupts, acquires timekeeper lock to serialize against
* concurrent updates from timekeeping and invalidates the VDSO data
* sequence counter to prevent concurrent readers from accessing
* inconsistent data.
*
* Returns: Saved interrupt flags which need to be handed in to
* vdso_update_end().
*/
unsigned long vdso_update_begin(void)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
unsigned long flags;
raw_spin_lock_irqsave(&timekeeper_lock, flags);
vdso_write_begin(vdata);
return flags;
}
/**
* vdso_update_end - End of a VDSO update section
* @flags: Interrupt flags as returned from vdso_update_begin()
*
* Pairs with vdso_update_begin(). Marks vdso data consistent, invokes data
* synchronization if the architecture requires it, drops timekeeper lock
* and restores interrupt flags.
*/
void vdso_update_end(unsigned long flags)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
vdso_write_end(vdata);
__arch_sync_vdso_data(vdata);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
}
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