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170 lines
4.9 KiB
170 lines
4.9 KiB
// 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 resolution 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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