time: Move time_t based interfaces to time32.h

Interfaces based on 'struct timespec' or 'struct timeval' should no
longer be used for new code, which can use either ktime_t or 'struct
timespec64' instead.

To make this a little clearer, this moves the various helpers into a new
time32.h header. For the moment, this gets included by the normal time.h,
but we may be able to separate it entirely when most users of time32.h
are gone.

Individual helpers in the new file can get removed once they become unused
in the future.

Since the contents of time32.h look a lot like what's in time64.h, I'm
reordering them during the move to make them more similar, and to allow
a follow-up patch to redirect the 'timespec' based functions to thei
'timespec64' based counterparts on 64-bit architectures later.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[jstultz: Whitespace & checkpatch fixups]
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 176 insertions, 0 deletions

diff --git a/include/linux/time32.h b/include/linux/time32.h
new file mode 100644
index 000000000000..9b9c43f0d39b
--- /dev/null
+++ b/include/linux/time32.h
@@ -0,0 +1,176 @@
+#ifndef _LINUX_TIME32_H
+#define _LINUX_TIME32_H
+/*
+ * These are all interfaces based on the old time_t definition
+ * that overflows in 2038 on 32-bit architectures. New code
+ * should use the replacements based on time64_t and timespec64.
+ *
+ * Any interfaces in here that become unused as we migrate
+ * code to time64_t should get removed.
+ */
+
+#include <linux/time64.h>
+
+#define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+
+static inline int timespec_equal(const struct timespec *a,
+				 const struct timespec *b)
+{
+	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
+}
+
+/*
+ * lhs < rhs:  return <0
+ * lhs == rhs: return 0
+ * lhs > rhs:  return >0
+ */
+static inline int timespec_compare(const struct timespec *lhs, const struct timespec *rhs)
+{
+	if (lhs->tv_sec < rhs->tv_sec)
+		return -1;
+	if (lhs->tv_sec > rhs->tv_sec)
+		return 1;
+	return lhs->tv_nsec - rhs->tv_nsec;
+}
+
+extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);
+
+static inline struct timespec timespec_add(struct timespec lhs,
+						struct timespec rhs)
+{
+	struct timespec ts_delta;
+
+	set_normalized_timespec(&ts_delta, lhs.tv_sec + rhs.tv_sec,
+				lhs.tv_nsec + rhs.tv_nsec);
+	return ts_delta;
+}
+
+/*
+ * sub = lhs - rhs, in normalized form
+ */
+static inline struct timespec timespec_sub(struct timespec lhs,
+						struct timespec rhs)
+{
+	struct timespec ts_delta;
+
+	set_normalized_timespec(&ts_delta, lhs.tv_sec - rhs.tv_sec,
+				lhs.tv_nsec - rhs.tv_nsec);
+	return ts_delta;
+}
+
+/*
+ * Returns true if the timespec is norm, false if denorm:
+ */
+static inline bool timespec_valid(const struct timespec *ts)
+{
+	/* Dates before 1970 are bogus */
+	if (ts->tv_sec < 0)
+		return false;
+	/* Can't have more nanoseconds then a second */
+	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
+		return false;
+	return true;
+}
+
+static inline bool timespec_valid_strict(const struct timespec *ts)
+{
+	if (!timespec_valid(ts))
+		return false;
+	/* Disallow values that could overflow ktime_t */
+	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
+		return false;
+	return true;
+}
+
+/**
+ * timespec_to_ns - Convert timespec to nanoseconds
+ * @ts:		pointer to the timespec variable to be converted
+ *
+ * Returns the scalar nanosecond representation of the timespec
+ * parameter.
+ */
+static inline s64 timespec_to_ns(const struct timespec *ts)
+{
+	return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
+}
+
+/**
+ * ns_to_timespec - Convert nanoseconds to timespec
+ * @nsec:	the nanoseconds value to be converted
+ *
+ * Returns the timespec representation of the nsec parameter.
+ */
+extern struct timespec ns_to_timespec(const s64 nsec);
+
+/**
+ * timespec_add_ns - Adds nanoseconds to a timespec
+ * @a:		pointer to timespec to be incremented
+ * @ns:		unsigned nanoseconds value to be added
+ *
+ * This must always be inlined because its used from the x86-64 vdso,
+ * which cannot call other kernel functions.
+ */
+static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
+{
+	a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
+	a->tv_nsec = ns;
+}
+
+/**
+ * time_to_tm - converts the calendar time to local broken-down time
+ *
+ * @totalsecs	the number of seconds elapsed since 00:00:00 on January 1, 1970,
+ *		Coordinated Universal Time (UTC).
+ * @offset	offset seconds adding to totalsecs.
+ * @result	pointer to struct tm variable to receive broken-down time
+ */
+static inline void time_to_tm(time_t totalsecs, int offset, struct tm *result)
+{
+	time64_to_tm(totalsecs, offset, result);
+}
+
+static inline unsigned long mktime(const unsigned int year,
+			const unsigned int mon, const unsigned int day,
+			const unsigned int hour, const unsigned int min,
+			const unsigned int sec)
+{
+	return mktime64(year, mon, day, hour, min, sec);
+}
+
+static inline bool timeval_valid(const struct timeval *tv)
+{
+	/* Dates before 1970 are bogus */
+	if (tv->tv_sec < 0)
+		return false;
+
+	/* Can't have more microseconds then a second */
+	if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
+		return false;
+
+	return true;
+}
+
+extern struct timespec timespec_trunc(struct timespec t, unsigned int gran);
+
+/**
+ * timeval_to_ns - Convert timeval to nanoseconds
+ * @ts:		pointer to the timeval variable to be converted
+ *
+ * Returns the scalar nanosecond representation of the timeval
+ * parameter.
+ */
+static inline s64 timeval_to_ns(const struct timeval *tv)
+{
+	return ((s64) tv->tv_sec * NSEC_PER_SEC) +
+		tv->tv_usec * NSEC_PER_USEC;
+}
+
+/**
+ * ns_to_timeval - Convert nanoseconds to timeval
+ * @nsec:	the nanoseconds value to be converted
+ *
+ * Returns the timeval representation of the nsec parameter.
+ */
+extern struct timeval ns_to_timeval(const s64 nsec);
+
+#endif