Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer core updates from Thomas Gleixner:
 "The timer changes contain:

   - posix timer code consolidation and fixes for odd corner cases

   - sched_clock implementation moved from ARM to core code to avoid
     duplication by other architectures

   - alarm timer updates

   - clocksource and clockevents unregistration facilities

   - clocksource/events support for new hardware

   - precise nanoseconds RTC readout (Xen feature)

   - generic support for Xen suspend/resume oddities

   - the usual lot of fixes and cleanups all over the place

  The parts which touch other areas (ARM/XEN) have been coordinated with
  the relevant maintainers.  Though this results in an handful of
  trivial to solve merge conflicts, which we preferred over nasty cross
  tree merge dependencies.

  The patches which have been committed in the last few days are bug
  fixes plus the posix timer lot.  The latter was in akpms queue and
  next for quite some time; they just got forgotten and Frederic
  collected them last minute."

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (59 commits)
  hrtimer: Remove unused variable
  hrtimers: Move SMP function call to thread context
  clocksource: Reselect clocksource when watchdog validated high-res capability
  posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting
  posix_timers: fix racy timer delta caching on task exit
  posix-timers: correctly get dying task time sample in posix_cpu_timer_schedule()
  selftests: add basic posix timers selftests
  posix_cpu_timers: consolidate expired timers check
  posix_cpu_timers: consolidate timer list cleanups
  posix_cpu_timer: consolidate expiry time type
  tick: Sanitize broadcast control logic
  tick: Prevent uncontrolled switch to oneshot mode
  tick: Make oneshot broadcast robust vs. CPU offlining
  x86: xen: Sync the CMOS RTC as well as the Xen wallclock
  x86: xen: Sync the wallclock when the system time is set
  timekeeping: Indicate that clock was set in the pvclock gtod notifier
  timekeeping: Pass flags instead of multiple bools to timekeeping_update()
  xen: Remove clock_was_set() call in the resume path
  hrtimers: Support resuming with two or more CPUs online (but stopped)
  timer: Fix jiffies wrap behavior of round_jiffies_common()
  ...

1 files changed, 108 insertions, 23 deletions

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 32b644f03690..929312180dd0 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/alarmtimer.h>
 #include <linux/file.h>
 #include <linux/poll.h>
 #include <linux/init.h>
@@ -26,7 +27,10 @@
 #include <linux/rcupdate.h>
 
 struct timerfd_ctx {
-	struct hrtimer tmr;
+	union {
+		struct hrtimer tmr;
+		struct alarm alarm;
+	} t;
 	ktime_t tintv;
 	ktime_t moffs;
 	wait_queue_head_t wqh;
@@ -41,14 +45,19 @@ struct timerfd_ctx {
 static LIST_HEAD(cancel_list);
 static DEFINE_SPINLOCK(cancel_lock);
 
+static inline bool isalarm(struct timerfd_ctx *ctx)
+{
+	return ctx->clockid == CLOCK_REALTIME_ALARM ||
+		ctx->clockid == CLOCK_BOOTTIME_ALARM;
+}
+
 /*
  * This gets called when the timer event triggers. We set the "expired"
  * flag, but we do not re-arm the timer (in case it's necessary,
  * tintv.tv64 != 0) until the timer is accessed.
  */
-static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
+static void timerfd_triggered(struct timerfd_ctx *ctx)
 {
-	struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
 	unsigned long flags;
 
 	spin_lock_irqsave(&ctx->wqh.lock, flags);
@@ -56,10 +65,25 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
 	ctx->ticks++;
 	wake_up_locked(&ctx->wqh);
 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
+}
 
+static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
+{
+	struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx,
+					       t.tmr);
+	timerfd_triggered(ctx);
 	return HRTIMER_NORESTART;
 }
 
+static enum alarmtimer_restart timerfd_alarmproc(struct alarm *alarm,
+	ktime_t now)
+{
+	struct timerfd_ctx *ctx = container_of(alarm, struct timerfd_ctx,
+					       t.alarm);
+	timerfd_triggered(ctx);
+	return ALARMTIMER_NORESTART;
+}
+
 /*
  * Called when the clock was set to cancel the timers in the cancel
  * list. This will wake up processes waiting on these timers. The
@@ -107,8 +131,9 @@ static bool timerfd_canceled(struct timerfd_ctx *ctx)
 
 static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags)
 {
-	if (ctx->clockid == CLOCK_REALTIME && (flags & TFD_TIMER_ABSTIME) &&
-	    (flags & TFD_TIMER_CANCEL_ON_SET)) {
+	if ((ctx->clockid == CLOCK_REALTIME ||
+	     ctx->clockid == CLOCK_REALTIME_ALARM) &&
+	    (flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) {
 		if (!ctx->might_cancel) {
 			ctx->might_cancel = true;
 			spin_lock(&cancel_lock);
@@ -124,7 +149,11 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
 {
 	ktime_t remaining;
 
-	remaining = hrtimer_expires_remaining(&ctx->tmr);
+	if (isalarm(ctx))
+		remaining = alarm_expires_remaining(&ctx->t.alarm);
+	else
+		remaining = hrtimer_expires_remaining(&ctx->t.tmr);
+
 	return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;
 }
 
@@ -142,11 +171,28 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
 	ctx->expired = 0;
 	ctx->ticks = 0;
 	ctx->tintv = timespec_to_ktime(ktmr->it_interval);
-	hrtimer_init(&ctx->tmr, clockid, htmode);
-	hrtimer_set_expires(&ctx->tmr, texp);
-	ctx->tmr.function = timerfd_tmrproc;
+
+	if (isalarm(ctx)) {
+		alarm_init(&ctx->t.alarm,
+			   ctx->clockid == CLOCK_REALTIME_ALARM ?
+			   ALARM_REALTIME : ALARM_BOOTTIME,
+			   timerfd_alarmproc);
+	} else {
+		hrtimer_init(&ctx->t.tmr, clockid, htmode);
+		hrtimer_set_expires(&ctx->t.tmr, texp);
+		ctx->t.tmr.function = timerfd_tmrproc;
+	}
+
 	if (texp.tv64 != 0) {
-		hrtimer_start(&ctx->tmr, texp, htmode);
+		if (isalarm(ctx)) {
+			if (flags & TFD_TIMER_ABSTIME)
+				alarm_start(&ctx->t.alarm, texp);
+			else
+				alarm_start_relative(&ctx->t.alarm, texp);
+		} else {
+			hrtimer_start(&ctx->t.tmr, texp, htmode);
+		}
+
 		if (timerfd_canceled(ctx))
 			return -ECANCELED;
 	}
@@ -158,7 +204,11 @@ static int timerfd_release(struct inode *inode, struct file *file)
 	struct timerfd_ctx *ctx = file->private_data;
 
 	timerfd_remove_cancel(ctx);
-	hrtimer_cancel(&ctx->tmr);
+
+	if (isalarm(ctx))
+		alarm_cancel(&ctx->t.alarm);
+	else
+		hrtimer_cancel(&ctx->t.tmr);
 	kfree_rcu(ctx, rcu);
 	return 0;
 }
@@ -215,9 +265,15 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
 			 * callback to avoid DoS attacks specifying a very
 			 * short timer period.
 			 */
-			ticks += hrtimer_forward_now(&ctx->tmr,
-						     ctx->tintv) - 1;
-			hrtimer_restart(&ctx->tmr);
+			if (isalarm(ctx)) {
+				ticks += alarm_forward_now(
+					&ctx->t.alarm, ctx->tintv) - 1;
+				alarm_restart(&ctx->t.alarm);
+			} else {
+				ticks += hrtimer_forward_now(&ctx->t.tmr,
+							     ctx->tintv) - 1;
+				hrtimer_restart(&ctx->t.tmr);
+			}
 		}
 		ctx->expired = 0;
 		ctx->ticks = 0;
@@ -259,7 +315,9 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 
 	if ((flags & ~TFD_CREATE_FLAGS) ||
 	    (clockid != CLOCK_MONOTONIC &&
-	     clockid != CLOCK_REALTIME))
+	     clockid != CLOCK_REALTIME &&
+	     clockid != CLOCK_REALTIME_ALARM &&
+	     clockid != CLOCK_BOOTTIME_ALARM))
 		return -EINVAL;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
@@ -268,7 +326,15 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 
 	init_waitqueue_head(&ctx->wqh);
 	ctx->clockid = clockid;
-	hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS);
+
+	if (isalarm(ctx))
+		alarm_init(&ctx->t.alarm,
+			   ctx->clockid == CLOCK_REALTIME_ALARM ?
+			   ALARM_REALTIME : ALARM_BOOTTIME,
+			   timerfd_alarmproc);
+	else
+		hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS);
+
 	ctx->moffs = ktime_get_monotonic_offset();
 
 	ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
@@ -305,8 +371,14 @@ static int do_timerfd_settime(int ufd, int flags,
 	 */
 	for (;;) {
 		spin_lock_irq(&ctx->wqh.lock);
-		if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
-			break;
+
+		if (isalarm(ctx)) {
+			if (alarm_try_to_cancel(&ctx->t.alarm) >= 0)
+				break;
+		} else {
+			if (hrtimer_try_to_cancel(&ctx->t.tmr) >= 0)
+				break;
+		}
 		spin_unlock_irq(&ctx->wqh.lock);
 		cpu_relax();
 	}
@@ -317,8 +389,12 @@ static int do_timerfd_settime(int ufd, int flags,
 	 * We do not update "ticks" and "expired" since the timer will be
 	 * re-programmed again in the following timerfd_setup() call.
 	 */
-	if (ctx->expired && ctx->tintv.tv64)
-		hrtimer_forward_now(&ctx->tmr, ctx->tintv);
+	if (ctx->expired && ctx->tintv.tv64) {
+		if (isalarm(ctx))
+			alarm_forward_now(&ctx->t.alarm, ctx->tintv);
+		else
+			hrtimer_forward_now(&ctx->t.tmr, ctx->tintv);
+	}
 
 	old->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
 	old->it_interval = ktime_to_timespec(ctx->tintv);
@@ -345,9 +421,18 @@ static int do_timerfd_gettime(int ufd, struct itimerspec *t)
 	spin_lock_irq(&ctx->wqh.lock);
 	if (ctx->expired && ctx->tintv.tv64) {
 		ctx->expired = 0;
-		ctx->ticks +=
-			hrtimer_forward_now(&ctx->tmr, ctx->tintv) - 1;
-		hrtimer_restart(&ctx->tmr);
+
+		if (isalarm(ctx)) {
+			ctx->ticks +=
+				alarm_forward_now(
+					&ctx->t.alarm, ctx->tintv) - 1;
+			alarm_restart(&ctx->t.alarm);
+		} else {
+			ctx->ticks +=
+				hrtimer_forward_now(&ctx->t.tmr, ctx->tintv)
+				- 1;
+			hrtimer_restart(&ctx->t.tmr);
+		}
 	}
 	t->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
 	t->it_interval = ktime_to_timespec(ctx->tintv);