The following patch adds a function to return tv_sec portion of
ktime_get_real_ts64() function in order to have a function that returns
seconds as 64-bit integers instead of 32-bit integers to address the
y2038 problem.
The function is similar to get_seconds() function except that it
includes read_seqcount_retry loop which is required for 32-bit
architectures. This is because 32-bit machines cannot access 64-bit
tk->xtime_sec variable atomically, requiring two 32-bit register loads.
Signed-off-by: Heena Sirwani <heenasirw...@gmail.com>
---
include/linux/timekeeping.h | 1 +
kernel/time/timekeeping.c | 19 +++++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 115d55e..91454de 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -29,6 +29,7 @@ struct timespec get_monotonic_coarse(void);
extern void getrawmonotonic(struct timespec *ts);
extern void ktime_get_ts64(struct timespec64 *ts);
extern time64_t ktime_get_seconds(void);
+extern time64_t ktime_get_real_seconds(void);
extern int __getnstimeofday64(struct timespec64 *tv);
extern void getnstimeofday64(struct timespec64 *tv);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e42da92..d731e7a 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -664,6 +664,25 @@ time64_t ktime_get_seconds(void)
}
EXPORT_SYMBOL_GPL(ktime_get_seconds);
+time64_t ktime_get_real_seconds(void)
+{
+ time64_t seconds;
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned int seq;
+
+ if (IS_ENABLED(CONFIG_64BIT))
+ return tk->xtime_sec;
+
+ do {
+ seq = read_seqcount_begin(&tk_core.seq);
+ seconds = tk->xtime_sec;
+
+ } while (read_seqcount_retry(&tk_core.seq, seq));
+
+ return seconds;
+}
+EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
+
#ifdef CONFIG_NTP_PPS
/**
--
1.9.1
--
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