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Commit b9ff604c authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Thomas Gleixner
Browse files

timekeeping: Add ktime_get_coarse_with_offset 



I have run into a couple of drivers using current_kernel_time()
suffering from the y2038 problem, and they could be converted
to using ktime_t, but don't have interfaces that skip the nanosecond
calculation at the moment.

This introduces ktime_get_coarse_with_offset() as a simpler
variant of ktime_get_with_offset(), and adds wrappers for the
three time domains we support with the existing function.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: y2038@lists.linaro.org
Cc: John Stultz <john.stultz@linaro.org>
Link: https://lkml.kernel.org/r/20180427134016.2525989-5-arnd@arndb.de
parent fb7fcc96

include/linux/timekeeping.h

+16 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ enum tk_offsets { 


extern ktime_t ktime_get(void);

extern ktime_t ktime_get_with_offset(enum tk_offsets offs);

extern ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs);

extern ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs);

extern ktime_t ktime_get_raw(void);

extern u32 ktime_get_resolution_ns(void);
@@ -63,6 +64,11 @@ static inline ktime_t ktime_get_real(void) 
	return ktime_get_with_offset(TK_OFFS_REAL);

}



static inline ktime_t ktime_get_coarse_real(void)

{

	return ktime_get_coarse_with_offset(TK_OFFS_REAL);

}



/**

 * ktime_get_boottime - Returns monotonic time since boot in ktime_t format

 *
@@ -74,6 +80,11 @@ static inline ktime_t ktime_get_boottime(void) 
	return ktime_get_with_offset(TK_OFFS_BOOT);

}



static inline ktime_t ktime_get_coarse_boottime(void)

{

	return ktime_get_coarse_with_offset(TK_OFFS_BOOT);

}



/**

 * ktime_get_clocktai - Returns the TAI time of day in ktime_t format

 */
@@ -82,6 +93,11 @@ static inline ktime_t ktime_get_clocktai(void) 
	return ktime_get_with_offset(TK_OFFS_TAI);

}



static inline ktime_t ktime_get_coarse_clocktai(void)

{

	return ktime_get_coarse_with_offset(TK_OFFS_TAI);

}



/**

 * ktime_mono_to_real - Convert monotonic time to clock realtime

 */

kernel/time/timekeeping.c

+19 −0
Original line number Diff line number Diff line
@@ -795,6 +795,25 @@ ktime_t ktime_get_with_offset(enum tk_offsets offs) 
}

EXPORT_SYMBOL_GPL(ktime_get_with_offset);



ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)

{

	struct timekeeper *tk = &tk_core.timekeeper;

	unsigned int seq;

	ktime_t base, *offset = offsets[offs];



	WARN_ON(timekeeping_suspended);



	do {

		seq = read_seqcount_begin(&tk_core.seq);

		base = ktime_add(tk->tkr_mono.base, *offset);



	} while (read_seqcount_retry(&tk_core.seq, seq));



	return base;



}

EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);



/**

 * ktime_mono_to_any() - convert mononotic time to any other time

 * @tmono:	time to convert.