Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1159 insertions, 0 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
new file mode 100644
index 000000000..96626f806
--- /dev/null
+++ b/drivers/rtc/interface.c
@@ -0,0 +1,1159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC subsystem, interface functions
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ */
+
+#include <linux/rtc.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/log2.h>
+#include <linux/workqueue.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rtc.h>
+
+static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
+static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
+
+static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	time64_t secs;
+
+	if (!rtc->offset_secs)
+		return;
+
+	secs = rtc_tm_to_time64(tm);
+
+	/*
+	 * Since the reading time values from RTC device are always in the RTC
+	 * original valid range, but we need to skip the overlapped region
+	 * between expanded range and original range, which is no need to add
+	 * the offset.
+	 */
+	if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
+	    (rtc->start_secs < rtc->range_min &&
+	     secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
+		return;
+
+	rtc_time64_to_tm(secs + rtc->offset_secs, tm);
+}
+
+static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	time64_t secs;
+
+	if (!rtc->offset_secs)
+		return;
+
+	secs = rtc_tm_to_time64(tm);
+
+	/*
+	 * If the setting time values are in the valid range of RTC hardware
+	 * device, then no need to subtract the offset when setting time to RTC
+	 * device. Otherwise we need to subtract the offset to make the time
+	 * values are valid for RTC hardware device.
+	 */
+	if (secs >= rtc->range_min && secs <= rtc->range_max)
+		return;
+
+	rtc_time64_to_tm(secs - rtc->offset_secs, tm);
+}
+
+static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	if (rtc->range_min != rtc->range_max) {
+		time64_t time = rtc_tm_to_time64(tm);
+		time64_t range_min = rtc->set_start_time ? rtc->start_secs :
+			rtc->range_min;
+		timeu64_t range_max = rtc->set_start_time ?
+			(rtc->start_secs + rtc->range_max - rtc->range_min) :
+			rtc->range_max;
+
+		if (time < range_min || time > range_max)
+			return -ERANGE;
+	}
+
+	return 0;
+}
+
+static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	int err;
+
+	if (!rtc->ops) {
+		err = -ENODEV;
+	} else if (!rtc->ops->read_time) {
+		err = -EINVAL;
+	} else {
+		memset(tm, 0, sizeof(struct rtc_time));
+		err = rtc->ops->read_time(rtc->dev.parent, tm);
+		if (err < 0) {
+			dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
+				err);
+			return err;
+		}
+
+		rtc_add_offset(rtc, tm);
+
+		err = rtc_valid_tm(tm);
+		if (err < 0)
+			dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
+	}
+	return err;
+}
+
+int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	err = __rtc_read_time(rtc, tm);
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_time(rtc_tm_to_time64(tm), err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_time);
+
+int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	int err, uie;
+
+	err = rtc_valid_tm(tm);
+	if (err != 0)
+		return err;
+
+	err = rtc_valid_range(rtc, tm);
+	if (err)
+		return err;
+
+	rtc_subtract_offset(rtc, tm);
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+	uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;
+#else
+	uie = rtc->uie_rtctimer.enabled;
+#endif
+	if (uie) {
+		err = rtc_update_irq_enable(rtc, 0);
+		if (err)
+			return err;
+	}
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (rtc->ops->set_time)
+		err = rtc->ops->set_time(rtc->dev.parent, tm);
+	else
+		err = -EINVAL;
+
+	pm_stay_awake(rtc->dev.parent);
+	mutex_unlock(&rtc->ops_lock);
+	/* A timer might have just expired */
+	schedule_work(&rtc->irqwork);
+
+	if (uie) {
+		err = rtc_update_irq_enable(rtc, 1);
+		if (err)
+			return err;
+	}
+
+	trace_rtc_set_time(rtc_tm_to_time64(tm), err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_time);
+
+static int rtc_read_alarm_internal(struct rtc_device *rtc,
+				   struct rtc_wkalrm *alarm)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	if (!rtc->ops) {
+		err = -ENODEV;
+	} else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
+		err = -EINVAL;
+	} else {
+		alarm->enabled = 0;
+		alarm->pending = 0;
+		alarm->time.tm_sec = -1;
+		alarm->time.tm_min = -1;
+		alarm->time.tm_hour = -1;
+		alarm->time.tm_mday = -1;
+		alarm->time.tm_mon = -1;
+		alarm->time.tm_year = -1;
+		alarm->time.tm_wday = -1;
+		alarm->time.tm_yday = -1;
+		alarm->time.tm_isdst = -1;
+		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
+	}
+
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_alarm(err?0:rtc_tm_to_time64(&alarm->time), err);
+	return err;
+}
+
+int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_time before, now;
+	int first_time = 1;
+	time64_t t_now, t_alm;
+	enum { none, day, month, year } missing = none;
+	unsigned int days;
+
+	/* The lower level RTC driver may return -1 in some fields,
+	 * creating invalid alarm->time values, for reasons like:
+	 *
+	 *   - The hardware may not be capable of filling them in;
+	 *     many alarms match only on time-of-day fields, not
+	 *     day/month/year calendar data.
+	 *
+	 *   - Some hardware uses illegal values as "wildcard" match
+	 *     values, which non-Linux firmware (like a BIOS) may try
+	 *     to set up as e.g. "alarm 15 minutes after each hour".
+	 *     Linux uses only oneshot alarms.
+	 *
+	 * When we see that here, we deal with it by using values from
+	 * a current RTC timestamp for any missing (-1) values.  The
+	 * RTC driver prevents "periodic alarm" modes.
+	 *
+	 * But this can be racey, because some fields of the RTC timestamp
+	 * may have wrapped in the interval since we read the RTC alarm,
+	 * which would lead to us inserting inconsistent values in place
+	 * of the -1 fields.
+	 *
+	 * Reading the alarm and timestamp in the reverse sequence
+	 * would have the same race condition, and not solve the issue.
+	 *
+	 * So, we must first read the RTC timestamp,
+	 * then read the RTC alarm value,
+	 * and then read a second RTC timestamp.
+	 *
+	 * If any fields of the second timestamp have changed
+	 * when compared with the first timestamp, then we know
+	 * our timestamp may be inconsistent with that used by
+	 * the low-level rtc_read_alarm_internal() function.
+	 *
+	 * So, when the two timestamps disagree, we just loop and do
+	 * the process again to get a fully consistent set of values.
+	 *
+	 * This could all instead be done in the lower level driver,
+	 * but since more than one lower level RTC implementation needs it,
+	 * then it's probably best to do it here instead of there..
+	 */
+
+	/* Get the "before" timestamp */
+	err = rtc_read_time(rtc, &before);
+	if (err < 0)
+		return err;
+	do {
+		if (!first_time)
+			memcpy(&before, &now, sizeof(struct rtc_time));
+		first_time = 0;
+
+		/* get the RTC alarm values, which may be incomplete */
+		err = rtc_read_alarm_internal(rtc, alarm);
+		if (err)
+			return err;
+
+		/* full-function RTCs won't have such missing fields */
+		err = rtc_valid_tm(&alarm->time);
+		if (!err)
+			goto done;
+
+		/* get the "after" timestamp, to detect wrapped fields */
+		err = rtc_read_time(rtc, &now);
+		if (err < 0)
+			return err;
+
+		/* note that tm_sec is a "don't care" value here: */
+	} while (before.tm_min  != now.tm_min ||
+		 before.tm_hour != now.tm_hour ||
+		 before.tm_mon  != now.tm_mon ||
+		 before.tm_year != now.tm_year);
+
+	/* Fill in the missing alarm fields using the timestamp; we
+	 * know there's at least one since alarm->time is invalid.
+	 */
+	if (alarm->time.tm_sec == -1)
+		alarm->time.tm_sec = now.tm_sec;
+	if (alarm->time.tm_min == -1)
+		alarm->time.tm_min = now.tm_min;
+	if (alarm->time.tm_hour == -1)
+		alarm->time.tm_hour = now.tm_hour;
+
+	/* For simplicity, only support date rollover for now */
+	if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
+		alarm->time.tm_mday = now.tm_mday;
+		missing = day;
+	}
+	if ((unsigned int)alarm->time.tm_mon >= 12) {
+		alarm->time.tm_mon = now.tm_mon;
+		if (missing == none)
+			missing = month;
+	}
+	if (alarm->time.tm_year == -1) {
+		alarm->time.tm_year = now.tm_year;
+		if (missing == none)
+			missing = year;
+	}
+
+	/* Can't proceed if alarm is still invalid after replacing
+	 * missing fields.
+	 */
+	err = rtc_valid_tm(&alarm->time);
+	if (err)
+		goto done;
+
+	/* with luck, no rollover is needed */
+	t_now = rtc_tm_to_time64(&now);
+	t_alm = rtc_tm_to_time64(&alarm->time);
+	if (t_now < t_alm)
+		goto done;
+
+	switch (missing) {
+	/* 24 hour rollover ... if it's now 10am Monday, an alarm that
+	 * that will trigger at 5am will do so at 5am Tuesday, which
+	 * could also be in the next month or year.  This is a common
+	 * case, especially for PCs.
+	 */
+	case day:
+		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
+		t_alm += 24 * 60 * 60;
+		rtc_time64_to_tm(t_alm, &alarm->time);
+		break;
+
+	/* Month rollover ... if it's the 31th, an alarm on the 3rd will
+	 * be next month.  An alarm matching on the 30th, 29th, or 28th
+	 * may end up in the month after that!  Many newer PCs support
+	 * this type of alarm.
+	 */
+	case month:
+		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
+		do {
+			if (alarm->time.tm_mon < 11) {
+				alarm->time.tm_mon++;
+			} else {
+				alarm->time.tm_mon = 0;
+				alarm->time.tm_year++;
+			}
+			days = rtc_month_days(alarm->time.tm_mon,
+					      alarm->time.tm_year);
+		} while (days < alarm->time.tm_mday);
+		break;
+
+	/* Year rollover ... easy except for leap years! */
+	case year:
+		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
+		do {
+			alarm->time.tm_year++;
+		} while (!is_leap_year(alarm->time.tm_year + 1900) &&
+			 rtc_valid_tm(&alarm->time) != 0);
+		break;
+
+	default:
+		dev_warn(&rtc->dev, "alarm rollover not handled\n");
+	}
+
+	err = rtc_valid_tm(&alarm->time);
+
+done:
+	if (err && alarm->enabled)
+		dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
+			 &alarm->time);
+	else
+		rtc_add_offset(rtc, &alarm->time);
+
+	return err;
+}
+
+/**
+ * rtc_read_next_alarm - read the next expiring alarm
+ * @rtc: RTC device
+ * @alarm: storage for the alarm information
+ *
+ * Read the next expiring alarm from the RTC timerqueue. This returns
+ * the alarm that will actually fire next, which may be different from
+ * rtc_read_alarm() if multiple timers are queued (e.g., alarmtimer
+ * and wakealarm sysfs both active).
+ *
+ * Returns: 0 on success, -ENOENT if no alarm is pending, or other error.
+ */
+int rtc_read_next_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	struct timerqueue_node *next;
+	int err;
+
+	if (!rtc || !alarm)
+		return -EINVAL;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	next = timerqueue_getnext(&rtc->timerqueue);
+	if (!next) {
+		err = -ENOENT;
+		goto unlock;
+	}
+
+	memset(alarm, 0, sizeof(struct rtc_wkalrm));
+	alarm->time = rtc_ktime_to_tm(next->expires);
+	alarm->enabled = 1;
+
+unlock:
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_next_alarm);
+
+int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+	if (!rtc->ops) {
+		err = -ENODEV;
+	} else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) {
+		err = -EINVAL;
+	} else {
+		memset(alarm, 0, sizeof(struct rtc_wkalrm));
+		alarm->enabled = rtc->aie_timer.enabled;
+		alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
+	}
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_alarm);
+
+static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	struct rtc_time tm;
+	time64_t now, scheduled;
+	int err;
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err)
+		return err;
+
+	scheduled = rtc_tm_to_time64(&alarm->time);
+
+	/* Make sure we're not setting alarms in the past */
+	err = __rtc_read_time(rtc, &tm);
+	if (err)
+		return err;
+	now = rtc_tm_to_time64(&tm);
+
+	if (scheduled <= now)
+		return -ETIME;
+	/*
+	 * XXX - We just checked to make sure the alarm time is not
+	 * in the past, but there is still a race window where if
+	 * the is alarm set for the next second and the second ticks
+	 * over right here, before we set the alarm.
+	 */
+
+	rtc_subtract_offset(rtc, &alarm->time);
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
+
+	/*
+	 * Check for potential race described above. If the waiting for next
+	 * second, and the second just ticked since the check above, either
+	 *
+	 * 1) It ticked after the alarm was set, and an alarm irq should be
+	 *    generated.
+	 *
+	 * 2) It ticked before the alarm was set, and alarm irq most likely will
+	 * not be generated.
+	 *
+	 * While we cannot easily check for which of these two scenarios we
+	 * are in, we can return -ETIME to signal that the timer has already
+	 * expired, which is true in both cases.
+	 */
+	if (!err && (scheduled - now) <= 1) {
+		err = __rtc_read_time(rtc, &tm);
+		if (err)
+			return err;
+		now = rtc_tm_to_time64(&tm);
+		if (scheduled <= now)
+			return -ETIME;
+	}
+
+	trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
+	return err;
+}
+
+int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	ktime_t alarm_time;
+	int err;
+
+	if (!rtc->ops)
+		return -ENODEV;
+	else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
+		return -EINVAL;
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err != 0)
+		return err;
+
+	err = rtc_valid_range(rtc, &alarm->time);
+	if (err)
+		return err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+	if (rtc->aie_timer.enabled)
+		rtc_timer_remove(rtc, &rtc->aie_timer);
+
+	alarm_time = rtc_tm_to_ktime(alarm->time);
+	/*
+	 * Round down so we never miss a deadline, checking for past deadline is
+	 * done in __rtc_set_alarm
+	 */
+	if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features))
+		alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC);
+
+	rtc->aie_timer.node.expires = alarm_time;
+	rtc->aie_timer.period = 0;
+	if (alarm->enabled)
+		err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
+
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_alarm);
+
+/* Called once per device from rtc_device_register */
+int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_time now;
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err != 0)
+		return err;
+
+	err = rtc_read_time(rtc, &now);
+	if (err)
+		return err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
+	rtc->aie_timer.period = 0;
+
+	/* Alarm has to be enabled & in the future for us to enqueue it */
+	if (alarm->enabled && (rtc_tm_to_ktime(now) <
+			 rtc->aie_timer.node.expires)) {
+		rtc->aie_timer.enabled = 1;
+		timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
+		trace_rtc_timer_enqueue(&rtc->aie_timer);
+	}
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
+
+int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	if (rtc->aie_timer.enabled != enabled) {
+		if (enabled)
+			err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
+		else
+			rtc_timer_remove(rtc, &rtc->aie_timer);
+	}
+
+	if (err)
+		/* nothing */;
+	else if (!rtc->ops)
+		err = -ENODEV;
+	else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
+		err = -EINVAL;
+	else
+		err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
+
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_alarm_irq_enable(enabled, err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
+
+int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+	if (enabled == 0 && rtc->uie_irq_active) {
+		mutex_unlock(&rtc->ops_lock);
+		return rtc_dev_update_irq_enable_emul(rtc, 0);
+	}
+#endif
+	/* make sure we're changing state */
+	if (rtc->uie_rtctimer.enabled == enabled)
+		goto out;
+
+	if (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) ||
+	    !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
+		mutex_unlock(&rtc->ops_lock);
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+		return rtc_dev_update_irq_enable_emul(rtc, enabled);
+#else
+		return -EINVAL;
+#endif
+	}
+
+	if (enabled) {
+		struct rtc_time tm;
+		ktime_t now, onesec;
+
+		err = __rtc_read_time(rtc, &tm);
+		if (err)
+			goto out;
+		onesec = ktime_set(1, 0);
+		now = rtc_tm_to_ktime(tm);
+		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
+		rtc->uie_rtctimer.period = ktime_set(1, 0);
+		err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
+		if (!err && rtc->ops && rtc->ops->alarm_irq_enable)
+			err = rtc->ops->alarm_irq_enable(rtc->dev.parent, 1);
+		if (err)
+			goto out;
+	} else {
+		rtc_timer_remove(rtc, &rtc->uie_rtctimer);
+	}
+
+out:
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
+
+/**
+ * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
+ * @rtc: pointer to the rtc device
+ * @num: number of occurrence of the event
+ * @mode: type of the event, RTC_AF, RTC_UF or RTC_PF
+ *
+ * This function is called when an AIE, UIE or PIE mode interrupt
+ * has occurred (or been emulated).
+ *
+ */
+void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
+{
+	unsigned long flags;
+
+	/* mark one irq of the appropriate mode */
+	spin_lock_irqsave(&rtc->irq_lock, flags);
+	rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
+	spin_unlock_irqrestore(&rtc->irq_lock, flags);
+
+	wake_up_interruptible(&rtc->irq_queue);
+	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
+}
+
+/**
+ * rtc_aie_update_irq - AIE mode rtctimer hook
+ * @rtc: pointer to the rtc_device
+ *
+ * This functions is called when the aie_timer expires.
+ */
+void rtc_aie_update_irq(struct rtc_device *rtc)
+{
+	rtc_handle_legacy_irq(rtc, 1, RTC_AF);
+}
+
+/**
+ * rtc_uie_update_irq - UIE mode rtctimer hook
+ * @rtc: pointer to the rtc_device
+ *
+ * This functions is called when the uie_timer expires.
+ */
+void rtc_uie_update_irq(struct rtc_device *rtc)
+{
+	rtc_handle_legacy_irq(rtc, 1,  RTC_UF);
+}
+
+/**
+ * rtc_pie_update_irq - PIE mode hrtimer hook
+ * @timer: pointer to the pie mode hrtimer
+ *
+ * This function is used to emulate PIE mode interrupts
+ * using an hrtimer. This function is called when the periodic
+ * hrtimer expires.
+ */
+enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
+{
+	struct rtc_device *rtc;
+	ktime_t period;
+	u64 count;
+
+	rtc = container_of(timer, struct rtc_device, pie_timer);
+
+	period = NSEC_PER_SEC / rtc->irq_freq;
+	count = hrtimer_forward_now(timer, period);
+
+	rtc_handle_legacy_irq(rtc, count, RTC_PF);
+
+	return HRTIMER_RESTART;
+}
+
+/**
+ * rtc_update_irq - Triggered when a RTC interrupt occurs.
+ * @rtc: the rtc device
+ * @num: how many irqs are being reported (usually one)
+ * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
+ * Context: any
+ */
+void rtc_update_irq(struct rtc_device *rtc,
+		    unsigned long num, unsigned long events)
+{
+	if (IS_ERR_OR_NULL(rtc))
+		return;
+
+	pm_stay_awake(rtc->dev.parent);
+	schedule_work(&rtc->irqwork);
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq);
+
+struct rtc_device *rtc_class_open(const char *name)
+{
+	struct device *dev;
+	struct rtc_device *rtc = NULL;
+
+	dev = class_find_device_by_name(&rtc_class, name);
+	if (dev)
+		rtc = to_rtc_device(dev);
+
+	if (rtc) {
+		if (!try_module_get(rtc->owner)) {
+			put_device(dev);
+			rtc = NULL;
+		}
+	}
+
+	return rtc;
+}
+EXPORT_SYMBOL_GPL(rtc_class_open);
+
+void rtc_class_close(struct rtc_device *rtc)
+{
+	module_put(rtc->owner);
+	put_device(&rtc->dev);
+}
+EXPORT_SYMBOL_GPL(rtc_class_close);
+
+static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
+{
+	/*
+	 * We always cancel the timer here first, because otherwise
+	 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
+	 * when we manage to start the timer before the callback
+	 * returns HRTIMER_RESTART.
+	 *
+	 * We cannot use hrtimer_cancel() here as a running callback
+	 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
+	 * would spin forever.
+	 */
+	if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
+		return -1;
+
+	if (enabled) {
+		ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
+
+		hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
+	}
+	return 0;
+}
+
+/**
+ * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
+ * @rtc: the rtc device
+ * @enabled: true to enable periodic IRQs
+ * Context: any
+ *
+ * Note that rtc_irq_set_freq() should previously have been used to
+ * specify the desired frequency of periodic IRQ.
+ */
+int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
+{
+	int err = 0;
+
+	while (rtc_update_hrtimer(rtc, enabled) < 0)
+		cpu_relax();
+
+	rtc->pie_enabled = enabled;
+
+	trace_rtc_irq_set_state(enabled, err);
+	return err;
+}
+
+/**
+ * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
+ * @rtc: the rtc device
+ * @freq: positive frequency
+ * Context: any
+ *
+ * Note that rtc_irq_set_state() is used to enable or disable the
+ * periodic IRQs.
+ */
+int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
+{
+	int err = 0;
+
+	if (freq <= 0 || freq > RTC_MAX_FREQ)
+		return -EINVAL;
+
+	rtc->irq_freq = freq;
+	while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
+		cpu_relax();
+
+	trace_rtc_irq_set_freq(freq, err);
+	return err;
+}
+
+/**
+ * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
+ * @rtc: rtc device
+ * @timer: timer being added.
+ *
+ * Enqueues a timer onto the rtc devices timerqueue and sets
+ * the next alarm event appropriately.
+ *
+ * Sets the enabled bit on the added timer.
+ *
+ * Must hold ops_lock for proper serialization of timerqueue
+ */
+static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
+{
+	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
+	struct rtc_time tm;
+	ktime_t now;
+	int err;
+
+	err = __rtc_read_time(rtc, &tm);
+	if (err)
+		return err;
+
+	timer->enabled = 1;
+	now = rtc_tm_to_ktime(tm);
+
+	/* Skip over expired timers */
+	while (next) {
+		if (next->expires >= now)
+			break;
+		next = timerqueue_iterate_next(next);
+	}
+
+	timerqueue_add(&rtc->timerqueue, &timer->node);
+	trace_rtc_timer_enqueue(timer);
+	if (!next || ktime_before(timer->node.expires, next->expires)) {
+		struct rtc_wkalrm alarm;
+
+		alarm.time = rtc_ktime_to_tm(timer->node.expires);
+		alarm.enabled = 1;
+		err = __rtc_set_alarm(rtc, &alarm);
+		if (err == -ETIME) {
+			pm_stay_awake(rtc->dev.parent);
+			schedule_work(&rtc->irqwork);
+		} else if (err) {
+			timerqueue_del(&rtc->timerqueue, &timer->node);
+			trace_rtc_timer_dequeue(timer);
+			timer->enabled = 0;
+			return err;
+		}
+	}
+	return 0;
+}
+
+static void rtc_alarm_disable(struct rtc_device *rtc)
+{
+	if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
+		return;
+
+	rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
+	trace_rtc_alarm_irq_enable(0, 0);
+}
+
+/**
+ * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
+ * @rtc: rtc device
+ * @timer: timer being removed.
+ *
+ * Removes a timer onto the rtc devices timerqueue and sets
+ * the next alarm event appropriately.
+ *
+ * Clears the enabled bit on the removed timer.
+ *
+ * Must hold ops_lock for proper serialization of timerqueue
+ */
+static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
+{
+	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
+
+	timerqueue_del(&rtc->timerqueue, &timer->node);
+	trace_rtc_timer_dequeue(timer);
+	timer->enabled = 0;
+	if (next == &timer->node) {
+		struct rtc_wkalrm alarm;
+		int err;
+
+		next = timerqueue_getnext(&rtc->timerqueue);
+		if (!next) {
+			rtc_alarm_disable(rtc);
+			return;
+		}
+		alarm.time = rtc_ktime_to_tm(next->expires);
+		alarm.enabled = 1;
+		err = __rtc_set_alarm(rtc, &alarm);
+		if (err == -ETIME) {
+			pm_stay_awake(rtc->dev.parent);
+			schedule_work(&rtc->irqwork);
+		}
+	}
+}
+
+/**
+ * rtc_timer_do_work - Expires rtc timers
+ * @work: work item
+ *
+ * Expires rtc timers. Reprograms next alarm event if needed.
+ * Called via worktask.
+ *
+ * Serializes access to timerqueue via ops_lock mutex
+ */
+void rtc_timer_do_work(struct work_struct *work)
+{
+	struct rtc_timer *timer;
+	struct timerqueue_node *next;
+	ktime_t now;
+	struct rtc_time tm;
+	int err;
+
+	struct rtc_device *rtc =
+		container_of(work, struct rtc_device, irqwork);
+
+	mutex_lock(&rtc->ops_lock);
+again:
+	err = __rtc_read_time(rtc, &tm);
+	if (err) {
+		mutex_unlock(&rtc->ops_lock);
+		return;
+	}
+	now = rtc_tm_to_ktime(tm);
+	while ((next = timerqueue_getnext(&rtc->timerqueue))) {
+		if (next->expires > now)
+			break;
+
+		/* expire timer */
+		timer = container_of(next, struct rtc_timer, node);
+		timerqueue_del(&rtc->timerqueue, &timer->node);
+		trace_rtc_timer_dequeue(timer);
+		timer->enabled = 0;
+		if (timer->func)
+			timer->func(timer->rtc);
+
+		trace_rtc_timer_fired(timer);
+		/* Re-add/fwd periodic timers */
+		if (ktime_to_ns(timer->period)) {
+			timer->node.expires = ktime_add(timer->node.expires,
+							timer->period);
+			timer->enabled = 1;
+			timerqueue_add(&rtc->timerqueue, &timer->node);
+			trace_rtc_timer_enqueue(timer);
+		}
+	}
+
+	/* Set next alarm */
+	if (next) {
+		struct rtc_wkalrm alarm;
+		int err;
+		int retry = 3;
+
+		alarm.time = rtc_ktime_to_tm(next->expires);
+		alarm.enabled = 1;
+reprogram:
+		err = __rtc_set_alarm(rtc, &alarm);
+		if (err == -ETIME) {
+			goto again;
+		} else if (err) {
+			if (retry-- > 0)
+				goto reprogram;
+
+			timer = container_of(next, struct rtc_timer, node);
+			timerqueue_del(&rtc->timerqueue, &timer->node);
+			trace_rtc_timer_dequeue(timer);
+			timer->enabled = 0;
+			dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
+			goto again;
+		}
+	} else {
+		rtc_alarm_disable(rtc);
+	}
+
+	pm_relax(rtc->dev.parent);
+	mutex_unlock(&rtc->ops_lock);
+}
+
+/* rtc_timer_init - Initializes an rtc_timer
+ * @timer: timer to be intiialized
+ * @f: function pointer to be called when timer fires
+ * @rtc: pointer to the rtc_device
+ *
+ * Kernel interface to initializing an rtc_timer.
+ */
+void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
+		    struct rtc_device *rtc)
+{
+	timerqueue_init(&timer->node);
+	timer->enabled = 0;
+	timer->func = f;
+	timer->rtc = rtc;
+}
+
+/* rtc_timer_start - Sets an rtc_timer to fire in the future
+ * @ rtc: rtc device to be used
+ * @ timer: timer being set
+ * @ expires: time at which to expire the timer
+ * @ period: period that the timer will recur
+ *
+ * Kernel interface to set an rtc_timer
+ */
+int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
+		    ktime_t expires, ktime_t period)
+{
+	int ret = 0;
+
+	mutex_lock(&rtc->ops_lock);
+	if (timer->enabled)
+		rtc_timer_remove(rtc, timer);
+
+	timer->node.expires = expires;
+	timer->period = period;
+
+	ret = rtc_timer_enqueue(rtc, timer);
+
+	mutex_unlock(&rtc->ops_lock);
+	return ret;
+}
+
+/* rtc_timer_cancel - Stops an rtc_timer
+ * @ rtc: rtc device to be used
+ * @ timer: timer being set
+ *
+ * Kernel interface to cancel an rtc_timer
+ */
+void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
+{
+	mutex_lock(&rtc->ops_lock);
+	if (timer->enabled)
+		rtc_timer_remove(rtc, timer);
+	mutex_unlock(&rtc->ops_lock);
+}
+
+/**
+ * rtc_read_offset - Read the amount of rtc offset in parts per billion
+ * @rtc: rtc device to be used
+ * @offset: the offset in parts per billion
+ *
+ * see below for details.
+ *
+ * Kernel interface to read rtc clock offset
+ * Returns 0 on success, or a negative number on error.
+ * If read_offset() is not implemented for the rtc, return -EINVAL
+ */
+int rtc_read_offset(struct rtc_device *rtc, long *offset)
+{
+	int ret;
+
+	if (!rtc->ops)
+		return -ENODEV;
+
+	if (!rtc->ops->read_offset)
+		return -EINVAL;
+
+	mutex_lock(&rtc->ops_lock);
+	ret = rtc->ops->read_offset(rtc->dev.parent, offset);
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_offset(*offset, ret);
+	return ret;
+}
+
+/**
+ * rtc_set_offset - Adjusts the duration of the average second
+ * @rtc: rtc device to be used
+ * @offset: the offset in parts per billion
+ *
+ * Some rtc's allow an adjustment to the average duration of a second
+ * to compensate for differences in the actual clock rate due to temperature,
+ * the crystal, capacitor, etc.
+ *
+ * The adjustment applied is as follows:
+ *   t = t0 * (1 + offset * 1e-9)
+ * where t0 is the measured length of 1 RTC second with offset = 0
+ *
+ * Kernel interface to adjust an rtc clock offset.
+ * Return 0 on success, or a negative number on error.
+ * If the rtc offset is not setable (or not implemented), return -EINVAL
+ */
+int rtc_set_offset(struct rtc_device *rtc, long offset)
+{
+	int ret;
+
+	if (!rtc->ops)
+		return -ENODEV;
+
+	if (!rtc->ops->set_offset)
+		return -EINVAL;
+
+	mutex_lock(&rtc->ops_lock);
+	ret = rtc->ops->set_offset(rtc->dev.parent, offset);
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_set_offset(offset, ret);
+	return ret;
+}