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1f45f1f33c
The clocksource validation which makes sure that the newly read value is not smaller than the last value only works if the clocksource mask is 64bit, i.e. the counter is 64bit wide. But we want to use that mechanism also for clocksources which are less than 64bit wide. So instead of checking whether bit 63 is set, we check whether the most significant bit of the clocksource mask is set in the delta result. If it is set, we return 0. [ tglx: Simplified the implementation, added a comment and massaged the commit message ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Cc: <linux-arm-kernel@lists.infradead.org> Link: http://lkml.kernel.org/r/56349607.6070708@huawei.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
36 lines
824 B
C
36 lines
824 B
C
#ifndef _TIMEKEEPING_INTERNAL_H
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#define _TIMEKEEPING_INTERNAL_H
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/*
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* timekeeping debug functions
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*/
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#include <linux/clocksource.h>
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#include <linux/time.h>
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#ifdef CONFIG_DEBUG_FS
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extern void tk_debug_account_sleep_time(struct timespec64 *t);
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#else
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#define tk_debug_account_sleep_time(x)
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#endif
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#ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
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static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)
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{
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cycle_t ret = (now - last) & mask;
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/*
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* Prevent time going backwards by checking the MSB of mask in
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* the result. If set, return 0.
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*/
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return ret & ~(mask >> 1) ? 0 : ret;
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}
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#else
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static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)
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{
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return (now - last) & mask;
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}
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#endif
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extern time64_t __ktime_get_real_seconds(void);
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#endif /* _TIMEKEEPING_INTERNAL_H */
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