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Subject[tip:timers/core] timekeeping: Remove boot time specific code
Commit-ID:  d6c7270e913db75ca5fdc79915ba780e97ae2857
Gitweb: https://git.kernel.org/tip/d6c7270e913db75ca5fdc79915ba780e97ae2857
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 1 Mar 2018 17:33:35 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Mar 2018 07:34:22 +0100

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: Thomas 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: Ingo Molnar <mingo@kernel.org>
---
include/linux/timekeeping.h | 42 +++++++++++++++++-------------------------
kernel/time/timekeeping.c | 31 -------------------------------
2 files changed, 17 insertions(+), 56 deletions(-)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 440b1935d3a5..abb396731332 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -38,15 +38,19 @@ extern int __getnstimeofday64(struct timespec64 *tv);
extern void getnstimeofday64(struct timespec64 *tv);
extern void getboottime64(struct timespec64 *ts);

-#define ktime_get_real_ts64(ts) getnstimeofday64(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());
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index b509fe7acd64..8355c8803282 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -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,
};

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