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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216// 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 fill_clock_configuration(struct vdso_clock *vc, const struct tk_read_base *base){ vc->cycle_last = base->cycle_last;#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT vc->max_cycles = base->clock->max_cycles;#endif vc->mask = base->mask; vc->mult = base->mult; vc->shift = base->shift;}
static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct timekeeper *tk){ struct vdso_clock *vc = vdata->clock_data; struct vdso_timestamp *vdso_ts; u64 nsec, sec;
fill_clock_configuration(&vc[CS_HRES_COARSE], &tk->tkr_mono); fill_clock_configuration(&vc[CS_RAW], &tk->tkr_raw);
/* CLOCK_MONOTONIC */ vdso_ts = &vc[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 = &vc[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 = &vc[CS_RAW].basetime[CLOCK_MONOTONIC_RAW]; vdso_ts->sec = tk->raw_sec; vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
/* CLOCK_TAI */ vdso_ts = &vc[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_time_data *vdata = vdso_k_time_data; struct vdso_clock *vc = vdata->clock_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; vc[CS_HRES_COARSE].clock_mode = clock_mode; vc[CS_RAW].clock_mode = clock_mode;
/* CLOCK_REALTIME also required for time() */ vdso_ts = &vc[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 = &vc[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE]; vdso_ts->sec = tk->xtime_sec; vdso_ts->nsec = tk->coarse_nsec;
/* CLOCK_MONOTONIC_COARSE */ vdso_ts = &vc[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE]; vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; nsec = tk->coarse_nsec; 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(). */ WRITE_ONCE(vdata->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_time_data(vdata, tk);
__arch_update_vdso_clock(&vc[CS_HRES_COARSE]); __arch_update_vdso_clock(&vc[CS_RAW]);
vdso_write_end(vdata);
__arch_sync_vdso_time_data(vdata);}
void update_vsyscall_tz(void){ struct vdso_time_data *vdata = vdso_k_time_data;
vdata->tz_minuteswest = sys_tz.tz_minuteswest; vdata->tz_dsttime = sys_tz.tz_dsttime;
__arch_sync_vdso_time_data(vdata);}
#ifdef CONFIG_POSIX_AUX_CLOCKSvoid vdso_time_update_aux(struct timekeeper *tk){ struct vdso_time_data *vdata = vdso_k_time_data; struct vdso_timestamp *vdso_ts; struct vdso_clock *vc; s32 clock_mode; u64 nsec;
vc = &vdata->aux_clock_data[tk->id - TIMEKEEPER_AUX_FIRST]; vdso_ts = &vc->basetime[VDSO_BASE_AUX]; clock_mode = tk->tkr_mono.clock->vdso_clock_mode; if (!tk->clock_valid) clock_mode = VDSO_CLOCKMODE_NONE;
/* copy vsyscall data */ vdso_write_begin_clock(vc);
vc->clock_mode = clock_mode;
if (clock_mode != VDSO_CLOCKMODE_NONE) { fill_clock_configuration(vc, &tk->tkr_mono);
vdso_ts->sec = tk->xtime_sec + tk->monotonic_to_aux.tv_sec;
nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; nsec += tk->monotonic_to_aux.tv_nsec; vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); nsec = nsec << tk->tkr_mono.shift; vdso_ts->nsec = nsec; }
__arch_update_vdso_clock(vc);
vdso_write_end_clock(vc);
__arch_sync_vdso_time_data(vdata);}#endif
/** * 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_time_data *vdata = vdso_k_time_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_time_data *vdata = vdso_k_time_data;
vdso_write_end(vdata); __arch_sync_vdso_time_data(vdata); timekeeper_unlock_irqrestore(flags);}