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