// 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;#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT	vdata[CS_HRES_COARSE].max_cycles	= tk->tkr_mono.clock->max_cycles;#endif	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;#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT	vdata[CS_RAW].max_cycles		= tk->tkr_raw.clock->max_cycles;#endif	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); 	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 = timekeeper_lock_irqsave(); 	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);	timekeeper_unlock_irqrestore(flags);}