[thirdparty/linux.git] / kernel / time / vsyscall.c

// 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>

static inline void update_vdso_data(struct vdso_data *vdata,
				    struct timekeeper *tk)
{
	struct vdso_timestamp *vdso_ts;
	u64 nsec;

	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_REALTIME */
	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
	vdso_ts->sec	= tk->xtime_sec;
	vdso_ts->nsec	= tk->tkr_mono.xtime_nsec;

	/* 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;

	/* 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_BOOTTIME */
	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
	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 +
		       ktime_to_ns(tk->offs_boot)) << 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;

	/* 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;

	/*
	 * 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);
}

void update_vsyscall(struct timekeeper *tk)
{
	struct vdso_data *vdata = __arch_get_k_vdso_data();
	struct vdso_timestamp *vdso_ts;
	u64 nsec;

	if (__arch_update_vdso_data()) {
		/*
		 * Some architectures might want to skip the update of the
		 * data page.
		 */
		return;
	}

	/* copy vsyscall data */
	vdso_write_begin(vdata);

	vdata[CS_HRES_COARSE].clock_mode	= __arch_get_clock_mode(tk);
	vdata[CS_RAW].clock_mode		= __arch_get_clock_mode(tk);

	/* 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);

	if (__arch_use_vsyscall(vdata))
		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();

	if (__arch_use_vsyscall(vdata)) {
		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);
}
Commit	Line	Data
44f57d78 VF	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Copyright 2019 ARM Ltd.
	4	*
	5	* Generic implementation of update_vsyscall and update_vsyscall_tz.
	6	*
	7	* Based on the x86 specific implementation.
	8	*/
	9
	10	#include <linux/hrtimer.h>
	11	#include <linux/timekeeper_internal.h>
	12	#include <vdso/datapage.h>
	13	#include <vdso/helpers.h>
	14	#include <vdso/vsyscall.h>
	15
	16	static inline void update_vdso_data(struct vdso_data *vdata,
	17	struct timekeeper *tk)
	18	{
	19	struct vdso_timestamp *vdso_ts;
	20	u64 nsec;
	21
	22	vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
	23	vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask;
	24	vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult;
	25	vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift;
	26	vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last;
	27	vdata[CS_RAW].mask = tk->tkr_raw.mask;
	28	vdata[CS_RAW].mult = tk->tkr_raw.mult;
	29	vdata[CS_RAW].shift = tk->tkr_raw.shift;
	30
	31	/* CLOCK_REALTIME */
	32	vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
	33	vdso_ts->sec = tk->xtime_sec;
	34	vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
	35
	36	/* CLOCK_MONOTONIC */
	37	vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
	38	vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
	39
	40	nsec = tk->tkr_mono.xtime_nsec;
	41	nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
	42	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
	43	nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
	44	vdso_ts->sec++;
	45	}
	46	vdso_ts->nsec = nsec;
	47
	48	/* CLOCK_MONOTONIC_RAW */
	49	vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
	50	vdso_ts->sec = tk->raw_sec;
	51	vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
	52
	53	/* CLOCK_BOOTTIME */
	54	vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
	55	vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
	56	nsec = tk->tkr_mono.xtime_nsec;
	57	nsec += ((u64)(tk->wall_to_monotonic.tv_nsec +
	58	ktime_to_ns(tk->offs_boot)) << tk->tkr_mono.shift);
	59	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
	60	nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
	61	vdso_ts->sec++;
	62	}
	63	vdso_ts->nsec = nsec;
	64
65	/* CLOCK_TAI */
66	vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
67	vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;
68	vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
69
70	/*
71	* Read without the seqlock held by clock_getres().
72	* Note: No need to have a second copy.
73	*/
74	WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
75	}
76
77	void update_vsyscall(struct timekeeper *tk)
78	{
79	struct vdso_data *vdata = __arch_get_k_vdso_data();
80	struct vdso_timestamp *vdso_ts;
81	u64 nsec;
82
83	if (__arch_update_vdso_data()) {
84	/*
85	* Some architectures might want to skip the update of the
86	* data page.
87	*/
88	return;
89	}
90
91	/* copy vsyscall data */
92	vdso_write_begin(vdata);
93
94	vdata[CS_HRES_COARSE].clock_mode = __arch_get_clock_mode(tk);
95	vdata[CS_RAW].clock_mode = __arch_get_clock_mode(tk);
96
97	/* CLOCK_REALTIME_COARSE */
98	vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
99	vdso_ts->sec = tk->xtime_sec;
100	vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
101
102	/* CLOCK_MONOTONIC_COARSE */
103	vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
104	vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
105	nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
106	nsec = nsec + tk->wall_to_monotonic.tv_nsec;
0df1c986	107	vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
44f57d78 VF	108
	109	if (__arch_use_vsyscall(vdata))
	110	update_vdso_data(vdata, tk);
	111
	112	__arch_update_vsyscall(vdata, tk);
	113
	114	vdso_write_end(vdata);
	115
	116	__arch_sync_vdso_data(vdata);
	117	}
	118
	119	void update_vsyscall_tz(void)
	120	{
	121	struct vdso_data *vdata = __arch_get_k_vdso_data();
	122
	123	if (__arch_use_vsyscall(vdata)) {
	124	vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
	125	vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
	126	}
	127
	128	__arch_sync_vdso_data(vdata);
	129	}