Since sched_clock always get stopped during suspend period, it
would make it hard to use the kernel log to compare with other
procssor generated log which running over the same machine.
[Absolutely not running linux]
So we need a way to recover the printk timestamp that including
suspend time in the old way, get_monotonic_boottime is a good
candidate, but it cannot be called after suspend process has happen.
Thus, it prevent printk to be used in every corner.
Export one warn less __get_monotonic_boottime to solve this issue.
Signed-off-by: Lei Wen <lei...@marvell.com>
---
include/linux/time.h | 1 +
kernel/time/timekeeping.c | 33 ++++++++++++++++++++++++++++-----
2 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/include/linux/time.h b/include/linux/time.h
index d5d229b..a2f5079 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -171,6 +171,7 @@ extern void getnstime_raw_and_real(struct timespec *ts_raw,
struct timespec *ts_real);
extern void getboottime(struct timespec *ts);
extern void monotonic_to_bootbased(struct timespec *ts);
+extern int __get_monotonic_boottime(struct timespec *ts);
extern void get_monotonic_boottime(struct timespec *ts);
extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5b40279..c196111 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1465,23 +1465,22 @@ void getboottime(struct timespec *ts)
EXPORT_SYMBOL_GPL(getboottime);
/**
- * get_monotonic_boottime - Returns monotonic time since boot
+ * __get_monotonic_boottime - Returns monotonic time since boot
* @ts: pointer to the timespec to be set
*
- * Returns the monotonic time since boot in a timespec.
+ * Update the monotonic time since boot in a timespec.
+ * Returns 0 on success, or -ve when suspended (timespec will be undefined).
*
* This is similar to CLOCK_MONTONIC/ktime_get_ts, but also
* includes the time spent in suspend.
*/
-void get_monotonic_boottime(struct timespec *ts)
+int __get_monotonic_boottime(struct timespec *ts)
{
struct timekeeper *tk = &timekeeper;
struct timespec tomono, sleep;
s64 nsec;
unsigned int seq;
- WARN_ON(timekeeping_suspended);
-
do {
seq = read_seqcount_begin(&timekeeper_seq);
ts->tv_sec = tk->xtime_sec;
@@ -1494,6 +1493,30 @@ void get_monotonic_boottime(struct timespec *ts)
ts->tv_sec += tomono.tv_sec + sleep.tv_sec;
ts->tv_nsec = 0;
timespec_add_ns(ts, nsec + tomono.tv_nsec + sleep.tv_nsec);
+
+ /*
+ * Do not bail out early, in case there were callers still using
+ * the value, even in the face of the WARN_ON.
+ */
+ if (unlikely(timekeeping_suspended))
+ return -EAGAIN;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__get_monotonic_boottime);
+
+/**
+ * get_monotonic_boottime - Returns monotonic time since boot
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the monotonic time since boot in a timespec.
+ * (WARN if suspended)
+ *
+ * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also
+ * includes the time spent in suspend.
+ */
+void get_monotonic_boottime(struct timespec *ts)
+{
+ WARN_ON(__get_monotonic_boottime(ts));
}
EXPORT_SYMBOL_GPL(get_monotonic_boottime);
--
1.8.3.2
--
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