um: fix global timer issue when using CONFIG_NO_HZ

[pandora-kernel.git] / arch / um / os-Linux / time.c

diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index bee98f4..6e3359d 100644 (file)
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -60,7 +60,7 @@ static inline long long timeval_to_ns(const struct timeval *tv)
 long long disable_timer(void)
 {
        struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
-       int remain, max = UM_NSEC_PER_SEC / UM_HZ;
+       long long remain, max = UM_NSEC_PER_SEC / UM_HZ;
 
        if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
                printk(UM_KERN_ERR "disable_timer - setitimer failed, "
@@ -106,6 +106,10 @@ static void deliver_alarm(void)
        unsigned long long this_tick = os_nsecs();
        int one_tick = UM_NSEC_PER_SEC / UM_HZ;
 
+       /* Protection against the host's time going backwards */
+       if ((last_tick != 0) && (this_tick < last_tick))
+               this_tick = last_tick;
+
        if (last_tick == 0)
                last_tick = this_tick - one_tick;
 
@@ -148,6 +152,9 @@ static int after_sleep_interval(struct timespec *ts)
                start_usecs = usec;
 
        start_usecs -= skew / UM_NSEC_PER_USEC;
+       if (start_usecs < 0)
+               start_usecs = 0;
+
        tv = ((struct timeval) { .tv_sec  = start_usecs / UM_USEC_PER_SEC,
                                 .tv_usec = start_usecs % UM_USEC_PER_SEC });
        interval = ((struct itimerval) { { 0, usec }, tv });