diff options
Diffstat (limited to 'kernel/hrtimer.c')
| -rw-r--r-- | kernel/hrtimer.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 690efd9d9adf..64d37a3c5948 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -581,6 +581,133 @@ void hrtimer_run_queues(void) } /* + * Sleep related functions: + */ + +/** + * schedule_hrtimer - sleep until timeout + * + * @timer: hrtimer variable initialized with the correct clock base + * @mode: timeout value is abs/rel + * + * Make the current task sleep until @timeout is + * elapsed. + * + * You can set the task state as follows - + * + * %TASK_UNINTERRUPTIBLE - at least @timeout is guaranteed to + * pass before the routine returns. The routine will return 0 + * + * %TASK_INTERRUPTIBLE - the routine may return early if a signal is + * delivered to the current task. In this case the remaining time + * will be returned + * + * The current task state is guaranteed to be TASK_RUNNING when this + * routine returns. + */ +static ktime_t __sched +schedule_hrtimer(struct hrtimer *timer, const enum hrtimer_mode mode) +{ + /* fn stays NULL, meaning single-shot wakeup: */ + timer->data = current; + + hrtimer_start(timer, timer->expires, mode); + + schedule(); + hrtimer_cancel(timer); + + /* Return the remaining time: */ + if (timer->state != HRTIMER_EXPIRED) + return ktime_sub(timer->expires, timer->base->get_time()); + else + return (ktime_t) {.tv64 = 0 }; +} + +static inline ktime_t __sched +schedule_hrtimer_interruptible(struct hrtimer *timer, + const enum hrtimer_mode mode) +{ + set_current_state(TASK_INTERRUPTIBLE); + + return schedule_hrtimer(timer, mode); +} + +static long __sched +nanosleep_restart(struct restart_block *restart, clockid_t clockid) +{ + struct timespec __user *rmtp, tu; + void *rfn_save = restart->fn; + struct hrtimer timer; + ktime_t rem; + + restart->fn = do_no_restart_syscall; + + hrtimer_init(&timer, clockid); + + timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0; + + rem = schedule_hrtimer_interruptible(&timer, HRTIMER_ABS); + + if (rem.tv64 <= 0) + return 0; + + rmtp = (struct timespec __user *) restart->arg2; + tu = ktime_to_timespec(rem); + if (rmtp && copy_to_user(rmtp, &tu, sizeof(tu))) + return -EFAULT; + + restart->fn = rfn_save; + + /* The other values in restart are already filled in */ + 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) +{ + struct restart_block *restart; + struct hrtimer timer; + struct timespec tu; + ktime_t rem; + + hrtimer_init(&timer, clockid); + + timer.expires = timespec_to_ktime(*rqtp); + + rem = schedule_hrtimer_interruptible(&timer, mode); + if (rem.tv64 <= 0) + return 0; + + /* Absolute timers do not update the rmtp value: */ + if (mode == HRTIMER_ABS) + return -ERESTARTNOHAND; + + tu = ktime_to_timespec(rem); + + if (rmtp && copy_to_user(rmtp, &tu, sizeof(tu))) + return -EFAULT; + + restart = ¤t_thread_info()->restart_block; + restart->fn = (clockid == CLOCK_MONOTONIC) ? + nanosleep_restart_mono : nanosleep_restart_real; + restart->arg0 = timer.expires.tv64 & 0xFFFFFFFF; + restart->arg1 = timer.expires.tv64 >> 32; + restart->arg2 = (unsigned long) rmtp; + + return -ERESTART_RESTARTBLOCK; +} + +/* * Functions related to boot-time initialization: */ static void __devinit init_hrtimers_cpu(int cpu) |