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Commit 3a978377 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by John Stultz
Browse files

clocksource: Make delta calculation a function 



We want to move the TSC sanity check into core code to make NMI safe
accessors to clock monotonic[_raw] possible. For this we need to
sanity check the delta calculation. Create a helper function and
convert all sites to use it.

[ Build fix from jstultz ]

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 6438e0dd

kernel/time/clocksource.c

+7 −5
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#include <linux/kthread.h>



#include "tick-internal.h"

#include "timekeeping_internal.h"



void timecounter_init(struct timecounter *tc,

		      const struct cyclecounter *cc,
@@ -249,7 +250,7 @@ void clocksource_mark_unstable(struct clocksource *cs) 
static void clocksource_watchdog(unsigned long data)

{

	struct clocksource *cs;

	cycle_t csnow, wdnow;

	cycle_t csnow, wdnow, delta;

	int64_t wd_nsec, cs_nsec;

	int next_cpu, reset_pending;
@@ -282,11 +283,12 @@ static void clocksource_watchdog(unsigned long data) 
			continue;

		}



		wd_nsec = clocksource_cyc2ns((wdnow - cs->wd_last) & watchdog->mask,

					     watchdog->mult, watchdog->shift);

		delta = clocksource_delta(wdnow, cs->wd_last, watchdog->mask);

		wd_nsec = clocksource_cyc2ns(delta, watchdog->mult,

					     watchdog->shift);



		cs_nsec = clocksource_cyc2ns((csnow - cs->cs_last) &

					     cs->mask, cs->mult, cs->shift);

		delta = clocksource_delta(csnow, cs->cs_last, cs->mask);

		cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift);

		cs->cs_last = csnow;

		cs->wd_last = wdnow;

kernel/time/timekeeping.c

+14 −12
Original line number Diff line number Diff line
@@ -173,7 +173,7 @@ static inline u32 arch_gettimeoffset(void) { return 0; } 


static inline s64 timekeeping_get_ns(struct timekeeper *tk)

{

	cycle_t cycle_now, cycle_delta;

	cycle_t cycle_now, delta;

	struct clocksource *clock;

	s64 nsec;
@@ -182,9 +182,9 @@ static inline s64 timekeeping_get_ns(struct timekeeper *tk) 
	cycle_now = clock->read(clock);



	/* calculate the delta since the last update_wall_time: */

	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;

	delta = clocksource_delta(cycle_now, clock->cycle_last, clock->mask);



	nsec = cycle_delta * tk->mult + tk->xtime_nsec;

	nsec = delta * tk->mult + tk->xtime_nsec;

	nsec >>= tk->shift;



	/* If arch requires, add in get_arch_timeoffset() */
@@ -193,7 +193,7 @@ static inline s64 timekeeping_get_ns(struct timekeeper *tk) 


static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)

{

	cycle_t cycle_now, cycle_delta;

	cycle_t cycle_now, delta;

	struct clocksource *clock;

	s64 nsec;
@@ -202,10 +202,10 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) 
	cycle_now = clock->read(clock);



	/* calculate the delta since the last update_wall_time: */

	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;

	delta = clocksource_delta(cycle_now, clock->cycle_last, clock->mask);



	/* convert delta to nanoseconds. */

	nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);

	nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift);



	/* If arch requires, add in get_arch_timeoffset() */

	return nsec + arch_gettimeoffset();
@@ -336,23 +336,23 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action) 
 */

static void timekeeping_forward_now(struct timekeeper *tk)

{

	cycle_t cycle_now, cycle_delta;

	cycle_t cycle_now, delta;

	struct clocksource *clock;

	s64 nsec;



	clock = tk->clock;

	cycle_now = clock->read(clock);

	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;

	delta = clocksource_delta(cycle_now, clock->cycle_last, clock->mask);

	tk->cycle_last = clock->cycle_last = cycle_now;



	tk->xtime_nsec += cycle_delta * tk->mult;

	tk->xtime_nsec += delta * tk->mult;



	/* If arch requires, add in get_arch_timeoffset() */

	tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;



	tk_normalize_xtime(tk);



	nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);

	nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift);

	timespec64_add_ns(&tk->raw_time, nsec);

}
@@ -1026,7 +1026,8 @@ static void timekeeping_resume(void) 
		u32 shift = clock->shift;

		s64 nsec = 0;



		cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;

		cycle_delta = clocksource_delta(cycle_now, clock->cycle_last,

						clock->mask);



		/*

		 * "cycle_delta * mutl" may cause 64 bits overflow, if the
@@ -1432,7 +1433,8 @@ void update_wall_time(void) 
#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET

	offset = real_tk->cycle_interval;

#else

	offset = (clock->read(clock) - clock->cycle_last) & clock->mask;

	offset = clocksource_delta(clock->read(clock), clock->cycle_last,

				   clock->mask);

#endif



	/* Check if there's really nothing to do */

kernel/time/timekeeping_internal.h

+6 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
/*

 * timekeeping debug functions

 */

#include <linux/clocksource.h>

#include <linux/time.h>



#ifdef CONFIG_DEBUG_FS
@@ -11,4 +12,9 @@ extern void tk_debug_account_sleep_time(struct timespec64 *t); 
#define tk_debug_account_sleep_time(x)

#endif



static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)

{

	return (now - last) & mask;

}



#endif /* _TIMEKEEPING_INTERNAL_H */