Merge branch 'smsc47b397-new-id' into release

[pandora-kernel.git] / kernel / hrtimer.c

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 668f396..98bee01 100644 (file)
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -325,6 +325,23 @@ u64 ktime_divns(const ktime_t kt, s64 div)
 }
 #endif /* BITS_PER_LONG >= 64 */
 
+/*
+ * Add two ktime values and do a safety check for overflow:
+ */
+ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
+{
+       ktime_t res = ktime_add(lhs, rhs);
+
+       /*
+        * We use KTIME_SEC_MAX here, the maximum timeout which we can
+        * return to user space in a timespec:
+        */
+       if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
+               res = ktime_set(KTIME_SEC_MAX, 0);
+
+       return res;
+}
+
 /*
  * Check, whether the timer is on the callback pending list
  */
@@ -425,6 +442,8 @@ static int hrtimer_reprogram(struct hrtimer *timer,
        ktime_t expires = ktime_sub(timer->expires, base->offset);
        int res;
 
+       WARN_ON_ONCE(timer->expires.tv64 < 0);
+
        /*
         * When the callback is running, we do not reprogram the clock event
         * device. The timer callback is either running on a different CPU or
@@ -435,6 +454,15 @@ static int hrtimer_reprogram(struct hrtimer *timer,
        if (hrtimer_callback_running(timer))
                return 0;
 
+       /*
+        * CLOCK_REALTIME timer might be requested with an absolute
+        * expiry time which is less than base->offset. Nothing wrong
+        * about that, just avoid to call into the tick code, which
+        * has now objections against negative expiry values.
+        */
+       if (expires.tv64 < 0)
+               return -ETIME;
+
        if (expires.tv64 >= expires_next->tv64)
                return 0;
 
@@ -682,13 +710,7 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
                 */
                orun++;
        }
-       timer->expires = ktime_add(timer->expires, interval);
-       /*
-        * Make sure, that the result did not wrap with a very large
-        * interval.
-        */
-       if (timer->expires.tv64 < 0)
-               timer->expires = ktime_set(KTIME_SEC_MAX, 0);
+       timer->expires = ktime_add_safe(timer->expires, interval);
 
        return orun;
 }
@@ -839,7 +861,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
        new_base = switch_hrtimer_base(timer, base);
 
        if (mode == HRTIMER_MODE_REL) {
-               tim = ktime_add(tim, new_base->get_time());
+               tim = ktime_add_safe(tim, new_base->get_time());
                /*
                 * CONFIG_TIME_LOW_RES is a temporary way for architectures
                 * to signal that they simply return xtime in
@@ -848,16 +870,8 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
                 * timeouts. This will go away with the GTOD framework.
                 */
 #ifdef CONFIG_TIME_LOW_RES
-               tim = ktime_add(tim, base->resolution);
+               tim = ktime_add_safe(tim, base->resolution);
 #endif
-               /*
-                * Careful here: User space might have asked for a
-                * very long sleep, so the add above might result in a
-                * negative number, which enqueues the timer in front
-                * of the queue.
-                */
-               if (tim.tv64 < 0)
-                       tim.tv64 = KTIME_MAX;
        }
        timer->expires = tim;
 
@@ -1319,13 +1333,26 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
        return t->task == NULL;
 }
 
+static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
+{
+       struct timespec rmt;
+       ktime_t rem;
+
+       rem = ktime_sub(timer->expires, timer->base->get_time());
+       if (rem.tv64 <= 0)
+               return 0;
+       rmt = ktime_to_timespec(rem);
+
+       if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+               return -EFAULT;
+
+       return 1;
+}
+
 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 {
        struct hrtimer_sleeper t;
-       struct timespec *rmtp;
-       ktime_t time;
-
-       restart->fn = do_no_restart_syscall;
+       struct timespec __user  *rmtp;
 
        hrtimer_init(&t.timer, restart->arg0, HRTIMER_MODE_ABS);
        t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2;
@@ -1333,26 +1360,22 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
        if (do_nanosleep(&t, HRTIMER_MODE_ABS))
                return 0;
 
-       rmtp = (struct timespec *)restart->arg1;
+       rmtp = (struct timespec __user *)restart->arg1;
        if (rmtp) {
-               time = ktime_sub(t.timer.expires, t.timer.base->get_time());
-               if (time.tv64 <= 0)
-                       return 0;
-               *rmtp = ktime_to_timespec(time);
+               int ret = update_rmtp(&t.timer, rmtp);
+               if (ret <= 0)
+                       return ret;
        }
 
-       restart->fn = hrtimer_nanosleep_restart;
-
        /* The other values in restart are already filled in */
        return -ERESTART_RESTARTBLOCK;
 }
 
-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
                       const enum hrtimer_mode mode, const clockid_t clockid)
 {
        struct restart_block *restart;
        struct hrtimer_sleeper t;
-       ktime_t rem;
 
        hrtimer_init(&t.timer, clockid, mode);
        t.timer.expires = timespec_to_ktime(*rqtp);
@@ -1364,10 +1387,9 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
                return -ERESTARTNOHAND;
 
        if (rmtp) {
-               rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
-               if (rem.tv64 <= 0)
-                       return 0;
-               *rmtp = ktime_to_timespec(rem);
+               int ret = update_rmtp(&t.timer, rmtp);
+               if (ret <= 0)
+                       return ret;
        }
 
        restart = &current_thread_info()->restart_block;
@@ -1383,8 +1405,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
 asmlinkage long
 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 {
-       struct timespec tu, rmt;
-       int ret;
+       struct timespec tu;
 
        if (copy_from_user(&tu, rqtp, sizeof(tu)))
                return -EFAULT;
@@ -1392,15 +1413,7 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
        if (!timespec_valid(&tu))
                return -EINVAL;
 
-       ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
-                               CLOCK_MONOTONIC);
-
-       if (ret && rmtp) {
-               if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
-                       return -EFAULT;
-       }
-
-       return ret;
+       return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 }
 
 /*