1 files changed, 47 insertions, 36 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index f1c4155b49ac..5ae51f1bc7c8 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -21,6 +21,12 @@
  *  Credits:
  *      based on kernel/timer.c
  *
+ *      Help, testing, suggestions, bugfixes, improvements were
+ *      provided by:
+ *
+ *      George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
+ *      et. al.
+ *
  *  For licencing details see kernel-base/COPYING
  */
 
@@ -66,6 +72,12 @@ EXPORT_SYMBOL_GPL(ktime_get_real);
 
 /*
  * The timer bases:
+ *
+ * Note: If we want to add new timer bases, we have to skip the two
+ * clock ids captured by the cpu-timers. We do this by holding empty
+ * entries rather than doing math adjustment of the clock ids.
+ * This ensures that we capture erroneous accesses to these clock ids
+ * rather than moving them into the range of valid clock id's.
  */
 
 #define MAX_HRTIMER_BASES 2
@@ -406,8 +418,19 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
         /* Switch the timer base, if necessary: */
         new_base = switch_hrtimer_base(timer, base);
 
-        if (mode == HRTIMER_REL)
+        if (mode == HRTIMER_REL) {
                 tim = ktime_add(tim, new_base->get_time());
+                /*
+                 * CONFIG_TIME_LOW_RES is a temporary way for architectures
+                 * to signal that they simply return xtime in
+                 * do_gettimeoffset(). In this case we want to round up by
+                 * resolution when starting a relative timer, to avoid short
+                 * timeouts. This will go away with the GTOD framework.
+                 */
+#ifdef CONFIG_TIME_LOW_RES
+                tim = ktime_add(tim, base->resolution);
+#endif
+        }
         timer->expires = tim;
 
         enqueue_hrtimer(timer, new_base);
@@ -483,29 +506,25 @@ ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
 }
 
 /**
- * hrtimer_rebase - rebase an initialized hrtimer to a different base
+ * hrtimer_init - initialize a timer to the given clock
  *
- * @timer:      the timer to be rebased
+ * @timer:      the timer to be initialized
  * @clock_id:   the clock to be used
+ * @mode:       timer mode abs/rel
  */
-void hrtimer_rebase(struct hrtimer *timer, const clockid_t clock_id)
+void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+                  enum hrtimer_mode mode)
 {
         struct hrtimer_base *bases;
 
+        memset(timer, 0, sizeof(struct hrtimer));
+
         bases = per_cpu(hrtimer_bases, raw_smp_processor_id());
-        timer->base = &bases[clock_id];
-}
 
-/**
- * hrtimer_init - initialize a timer to the given clock
- *
- * @timer:      the timer to be initialized
- * @clock_id:   the clock to be used
- */
-void hrtimer_init(struct hrtimer *timer, const clockid_t clock_id)
-{
-        memset(timer, 0, sizeof(struct hrtimer));
-        hrtimer_rebase(timer, clock_id);
+        if (clock_id == CLOCK_REALTIME && mode != HRTIMER_ABS)
+                clock_id = CLOCK_MONOTONIC;
+
+        timer->base = &bases[clock_id];
 }
 
 /**
@@ -550,6 +569,7 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
                 fn = timer->function;
                 data = timer->data;
                 set_curr_timer(base, timer);
+                timer->state = HRTIMER_RUNNING;
                 __remove_hrtimer(timer, base);
                 spin_unlock_irq(&base->lock);
 
@@ -565,6 +585,10 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
 
                 spin_lock_irq(&base->lock);
 
+                /* Another CPU has added back the timer */
+                if (timer->state != HRTIMER_RUNNING)
+                        continue;
+
                 if (restart == HRTIMER_RESTART)
                         enqueue_hrtimer(timer, base);
                 else
@@ -638,8 +662,7 @@ schedule_hrtimer_interruptible(struct hrtimer *timer,
         return schedule_hrtimer(timer, mode);
 }
 
-static long __sched
-nanosleep_restart(struct restart_block *restart, clockid_t clockid)
+static long __sched nanosleep_restart(struct restart_block *restart)
 {
         struct timespec __user *rmtp;
         struct timespec tu;
@@ -649,7 +672,7 @@ nanosleep_restart(struct restart_block *restart, clockid_t clockid)
 
         restart->fn = do_no_restart_syscall;
 
-        hrtimer_init(&timer, clockid);
+        hrtimer_init(&timer, (clockid_t) restart->arg3, HRTIMER_ABS);
 
         timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0;
 
@@ -669,16 +692,6 @@ nanosleep_restart(struct restart_block *restart, clockid_t clockid)
         return -ERESTART_RESTARTBLOCK;
 }
 
-static long __sched nanosleep_restart_mono(struct restart_block *restart)
-{
-        return nanosleep_restart(restart, CLOCK_MONOTONIC);
-}
-
-static long __sched nanosleep_restart_real(struct restart_block *restart)
-{
-        return nanosleep_restart(restart, CLOCK_REALTIME);
-}
-
 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
                        const enum hrtimer_mode mode, const clockid_t clockid)
 {
@@ -687,7 +700,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
         struct timespec tu;
         ktime_t rem;
 
-        hrtimer_init(&timer, clockid);
+        hrtimer_init(&timer, clockid, mode);
 
         timer.expires = timespec_to_ktime(*rqtp);
 
@@ -695,7 +708,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
         if (rem.tv64 <= 0)
                 return 0;
 
-        /* Absolute timers do not update the rmtp value: */
+        /* Absolute timers do not update the rmtp value and restart: */
         if (mode == HRTIMER_ABS)
                 return -ERESTARTNOHAND;
 
@@ -705,11 +718,11 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
                 return -EFAULT;
 
         restart = &current_thread_info()->restart_block;
-        restart->fn = (clockid == CLOCK_MONOTONIC) ?
-                nanosleep_restart_mono : nanosleep_restart_real;
+        restart->fn = nanosleep_restart;
         restart->arg0 = timer.expires.tv64 & 0xFFFFFFFF;
         restart->arg1 = timer.expires.tv64 >> 32;
         restart->arg2 = (unsigned long) rmtp;
+        restart->arg3 = (unsigned long) timer.base->index;
 
         return -ERESTART_RESTARTBLOCK;
 }
@@ -736,10 +749,8 @@ static void __devinit init_hrtimers_cpu(int cpu)
         struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu);
         int i;
 
-        for (i = 0; i < MAX_HRTIMER_BASES; i++) {
+        for (i = 0; i < MAX_HRTIMER_BASES; i++, base++)
                 spin_lock_init(&base->lock);
-                base++;
-        }
 }
 
 #ifdef CONFIG_HOTPLUG_CPU