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Commit d6c7270e authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

timekeeping: Remove boot time specific code 



Now that the MONOTONIC and BOOTTIME clocks are the same, remove all the
special handling from timekeeping. Keep wrappers for the existing users of
the *boot* timekeeper interfaces.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20180301165150.236279497@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent f2d6fdbf

include/linux/timekeeping.h

+17 −25
Original line number Diff line number Diff line
@@ -40,13 +40,17 @@ extern void getboottime64(struct timespec64 *ts); 


#define ktime_get_real_ts64(ts)		getnstimeofday64(ts)



/* Clock BOOTTIME compatibility wrappers */

static inline void get_monotonic_boottime64(struct timespec64 *ts)

{

	ktime_get_ts64(ts);

}



/*

 * ktime_t based interfaces

 */



enum tk_offsets {

	TK_OFFS_REAL,

	TK_OFFS_BOOT,

	TK_OFFS_TAI,

	TK_OFFS_MAX,

};
@@ -57,6 +61,10 @@ 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);



/* Clock BOOTTIME compatibility wrappers */

static inline ktime_t ktime_get_boottime(void) { return ktime_get(); }

static inline u64 ktime_get_boot_ns(void) { return ktime_get(); }



/**

 * ktime_get_real - get the real (wall-) time in ktime_t format

 */
@@ -65,17 +73,6 @@ static inline ktime_t ktime_get_real(void) 
	return ktime_get_with_offset(TK_OFFS_REAL);

}



/**

 * ktime_get_boottime - Returns monotonic time since boot in ktime_t format

 *

 * This is similar to CLOCK_MONTONIC/ktime_get, but also includes the

 * time spent in suspend.

 */

static inline ktime_t ktime_get_boottime(void)

{

	return ktime_get_with_offset(TK_OFFS_BOOT);

}



/**

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

 */
@@ -102,11 +99,6 @@ static inline u64 ktime_get_real_ns(void) 
	return ktime_to_ns(ktime_get_real());

}



static inline u64 ktime_get_boot_ns(void)

{

	return ktime_to_ns(ktime_get_boottime());

}



static inline u64 ktime_get_tai_ns(void)

{

	return ktime_to_ns(ktime_get_clocktai());
@@ -119,17 +111,17 @@ static inline u64 ktime_get_raw_ns(void) 


extern u64 ktime_get_mono_fast_ns(void);

extern u64 ktime_get_raw_fast_ns(void);

extern u64 ktime_get_boot_fast_ns(void);

extern u64 ktime_get_real_fast_ns(void);



/*

 * timespec64 interfaces utilizing the ktime based ones

 */

static inline void get_monotonic_boottime64(struct timespec64 *ts)

/* Clock BOOTTIME compatibility wrappers */

static inline u64 ktime_get_boot_fast_ns(void)

{

	*ts = ktime_to_timespec64(ktime_get_boottime());

	return ktime_get_mono_fast_ns();

}



/*

 * timespec64 interfaces utilizing the ktime based ones

 */

static inline void timekeeping_clocktai64(struct timespec64 *ts)

{

	*ts = ktime_to_timespec64(ktime_get_clocktai());

kernel/time/timekeeping.c

+0 −31
Original line number Diff line number Diff line
@@ -473,36 +473,6 @@ u64 ktime_get_raw_fast_ns(void) 
}

EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);



/**

 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.

 *

 * To keep it NMI safe since we're accessing from tracing, we're not using a

 * separate timekeeper with updates to monotonic clock and boot offset

 * protected with seqlocks. This has the following minor side effects:

 *

 * (1) Its possible that a timestamp be taken after the boot offset is updated

 * but before the timekeeper is updated. If this happens, the new boot offset

 * is added to the old timekeeping making the clock appear to update slightly

 * earlier:

 *    CPU 0                                        CPU 1

 *    timekeeping_inject_sleeptime64()

 *    __timekeeping_inject_sleeptime(tk, delta);

 *                                                 timestamp();

 *    timekeeping_update(tk, TK_CLEAR_NTP...);

 *

 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be

 * partially updated.  Since the tk->offs_boot update is a rare event, this

 * should be a rare occurrence which postprocessing should be able to handle.

 */

u64 notrace ktime_get_boot_fast_ns(void)

{

	struct timekeeper *tk = &tk_core.timekeeper;



	return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));

}

EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);





/*

 * See comment for __ktime_get_fast_ns() vs. timestamp ordering

 */
@@ -794,7 +764,6 @@ EXPORT_SYMBOL_GPL(ktime_get_resolution_ns); 


static ktime_t *offsets[TK_OFFS_MAX] = {

	[TK_OFFS_REAL]	= &tk_core.timekeeper.offs_real,

	[TK_OFFS_BOOT]	= &tk_core.timekeeper.offs_boot,

	[TK_OFFS_TAI]	= &tk_core.timekeeper.offs_tai,

};