| /* |
| * linux/kernel/posix_timers.c |
| * |
| * |
| * 2002-10-15 Posix Clocks & timers by George Anzinger |
| * Copyright (C) 2002 by MontaVista Software. |
| */ |
| |
| /* These are all the functions necessary to implement |
| * POSIX clocks & timers |
| */ |
| #include <linux/mm.h> |
| #include <linux/smp_lock.h> |
| #include <linux/interrupt.h> |
| #include <linux/slab.h> |
| #include <linux/time.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/semaphore.h> |
| #include <linux/list.h> |
| #include <linux/init.h> |
| #include <linux/compiler.h> |
| #include <linux/idr.h> |
| #include <linux/posix-timers.h> |
| #include <linux/wait.h> |
| |
| #ifndef div_long_long_rem |
| #include <asm/div64.h> |
| |
| #define div_long_long_rem(dividend,divisor,remainder) ({ \ |
| u64 result = dividend; \ |
| *remainder = do_div(result,divisor); \ |
| result; }) |
| |
| #endif |
| |
| /* |
| * Management arrays for POSIX timers. Timers are kept in slab memory |
| * Timer ids are allocated by an external routine that keeps track of the |
| * id and the timer. The external interface is: |
| * |
| * void *idr_find(struct idr *idp, int id); to find timer_id <id> |
| * int idr_get_new(struct idr *idp, void *ptr); to get a new id and |
| * related it to <ptr> |
| * void idr_remove(struct idr *idp, int id); to release <id> |
| * void idr_init(struct idr *idp); to initialize <idp> |
| * which we supply. |
| * The idr_get_new *may* call slab for more memory so it must not be |
| * called under a spin lock. Likewise idr_remore may release memory |
| * (but it may be ok to do this under a lock...). |
| * idr_find is just a memory look up and is quite fast. A zero return |
| * indicates that the requested id does not exist. |
| */ |
| |
| /* |
| * Lets keep our timers in a slab cache :-) |
| */ |
| static kmem_cache_t *posix_timers_cache; |
| static struct idr posix_timers_id; |
| static spinlock_t idr_lock = SPIN_LOCK_UNLOCKED; |
| |
| /* |
| * Just because the timer is not in the timer list does NOT mean it is |
| * inactive. It could be in the "fire" routine getting a new expire time. |
| */ |
| #define TIMER_INACTIVE 1 |
| #define TIMER_RETRY 1 |
| |
| #ifdef CONFIG_SMP |
| # define timer_active(tmr) \ |
| ((tmr)->it_timer.entry.prev != (void *)TIMER_INACTIVE) |
| # define set_timer_inactive(tmr) \ |
| do { \ |
| (tmr)->it_timer.entry.prev = (void *)TIMER_INACTIVE; \ |
| } while (0) |
| #else |
| # define timer_active(tmr) BARFY // error to use outside of SMP |
| # define set_timer_inactive(tmr) do { } while (0) |
| #endif |
| |
| /* |
| * For some reason mips/mips64 define the SIGEV constants plus 128. |
| * Here we define a mask to get rid of the common bits. The |
| * optimizer should make this costless to all but mips. |
| */ |
| #define MIPS_SIGEV ~(SIGEV_NONE & \ |
| SIGEV_SIGNAL & \ |
| SIGEV_THREAD & \ |
| SIGEV_THREAD_ID) |
| |
| #define REQUEUE_PENDING 1 |
| /* |
| * The timer ID is turned into a timer address by idr_find(). |
| * Verifying a valid ID consists of: |
| * |
| * a) checking that idr_find() returns other than zero. |
| * b) checking that the timer id matches the one in the timer itself. |
| * c) that the timer owner is in the callers thread group. |
| */ |
| |
| /* |
| * CLOCKs: The POSIX standard calls for a couple of clocks and allows us |
| * to implement others. This structure defines the various |
| * clocks and allows the possibility of adding others. We |
| * provide an interface to add clocks to the table and expect |
| * the "arch" code to add at least one clock that is high |
| * resolution. Here we define the standard CLOCK_REALTIME as a |
| * 1/HZ resolution clock. |
| * |
| * CPUTIME & THREAD_CPUTIME: We are not, at this time, definding these |
| * two clocks (and the other process related clocks (Std |
| * 1003.1d-1999). The way these should be supported, we think, |
| * is to use large negative numbers for the two clocks that are |
| * pinned to the executing process and to use -pid for clocks |
| * pinned to particular pids. Calls which supported these clock |
| * ids would split early in the function. |
| * |
| * RESOLUTION: Clock resolution is used to round up timer and interval |
| * times, NOT to report clock times, which are reported with as |
| * much resolution as the system can muster. In some cases this |
| * resolution may depend on the underlaying clock hardware and |
| * may not be quantifiable until run time, and only then is the |
| * necessary code is written. The standard says we should say |
| * something about this issue in the documentation... |
| * |
| * FUNCTIONS: The CLOCKs structure defines possible functions to handle |
| * various clock functions. For clocks that use the standard |
| * system timer code these entries should be NULL. This will |
| * allow dispatch without the overhead of indirect function |
| * calls. CLOCKS that depend on other sources (e.g. WWV or GPS) |
| * must supply functions here, even if the function just returns |
| * ENOSYS. The standard POSIX timer management code assumes the |
| * following: 1.) The k_itimer struct (sched.h) is used for the |
| * timer. 2.) The list, it_lock, it_clock, it_id and it_process |
| * fields are not modified by timer code. |
| * |
| * At this time all functions EXCEPT clock_nanosleep can be |
| * redirected by the CLOCKS structure. Clock_nanosleep is in |
| * there, but the code ignors it. |
| * |
| * Permissions: It is assumed that the clock_settime() function defined |
| * for each clock will take care of permission checks. Some |
| * clocks may be set able by any user (i.e. local process |
| * clocks) others not. Currently the only set able clock we |
| * have is CLOCK_REALTIME and its high res counter part, both of |
| * which we beg off on and pass to do_sys_settimeofday(). |
| */ |
| |
| static struct k_clock posix_clocks[MAX_CLOCKS]; |
| |
| #define if_clock_do(clock_fun,alt_fun,parms) \ |
| (!clock_fun) ? alt_fun parms : clock_fun parms |
| |
| #define p_timer_get(clock,a,b) \ |
| if_clock_do((clock)->timer_get,do_timer_gettime, (a,b)) |
| |
| #define p_nsleep(clock,a,b,c) \ |
| if_clock_do((clock)->nsleep, do_nsleep, (a,b,c)) |
| |
| #define p_timer_del(clock,a) \ |
| if_clock_do((clock)->timer_del, do_timer_delete, (a)) |
| |
| void register_posix_clock(int clock_id, struct k_clock *new_clock); |
| static int do_posix_gettime(struct k_clock *clock, struct timespec *tp); |
| int do_posix_clock_monotonic_gettime(struct timespec *tp); |
| int do_posix_clock_monotonic_settime(struct timespec *tp); |
| static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags); |
| static inline void unlock_timer(struct k_itimer *timr, unsigned long flags); |
| |
| /* |
| * Initialize everything, well, just everything in Posix clocks/timers ;) |
| */ |
| static __init int init_posix_timers(void) |
| { |
| struct k_clock clock_realtime = {.res = NSEC_PER_SEC / HZ }; |
| struct k_clock clock_monotonic = {.res = NSEC_PER_SEC / HZ, |
| .clock_get = do_posix_clock_monotonic_gettime, |
| .clock_set = do_posix_clock_monotonic_settime |
| }; |
| |
| register_posix_clock(CLOCK_REALTIME, &clock_realtime); |
| register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic); |
| |
| posix_timers_cache = kmem_cache_create("posix_timers_cache", |
| sizeof (struct k_itimer), 0, 0, 0, 0); |
| idr_init(&posix_timers_id); |
| |
| return 0; |
| } |
| |
| __initcall(init_posix_timers); |
| |
| static void tstojiffie(struct timespec *tp, int res, u64 *jiff) |
| { |
| unsigned long sec = tp->tv_sec; |
| long nsec = tp->tv_nsec + res - 1; |
| |
| if (nsec > NSEC_PER_SEC) { |
| sec++; |
| nsec -= NSEC_PER_SEC; |
| } |
| |
| /* |
| * A note on jiffy overflow: It is possible for the system to |
| * have been up long enough for the jiffies quanity to overflow. |
| * In order for correct timer evaluations we require that the |
| * specified time be somewhere between now and now + (max |
| * unsigned int/2). Times beyond this will be truncated back to |
| * this value. This is done in the absolute adjustment code, |
| * below. Here it is enough to just discard the high order |
| * bits. |
| */ |
| *jiff = (u64)sec * HZ; |
| /* |
| * Do the res thing. (Don't forget the add in the declaration of nsec) |
| */ |
| nsec -= nsec % res; |
| /* |
| * Split to jiffie and sub jiffie |
| */ |
| *jiff += nsec / (NSEC_PER_SEC / HZ); |
| } |
| |
| static void tstotimer(struct itimerspec *time, struct k_itimer *timer) |
| { |
| u64 result; |
| int res = posix_clocks[timer->it_clock].res; |
| |
| tstojiffie(&time->it_value, res, &result); |
| timer->it_timer.expires = (unsigned long)result; |
| tstojiffie(&time->it_interval, res, &result); |
| timer->it_incr = (unsigned long)result; |
| } |
| |
| static void schedule_next_timer(struct k_itimer *timr) |
| { |
| struct now_struct now; |
| |
| /* Set up the timer for the next interval (if there is one) */ |
| if (!timr->it_incr) |
| return; |
| |
| posix_get_now(&now); |
| do { |
| posix_bump_timer(timr); |
| }while (posix_time_before(&timr->it_timer, &now)); |
| |
| timr->it_overrun_last = timr->it_overrun; |
| timr->it_overrun = -1; |
| ++timr->it_requeue_pending; |
| add_timer(&timr->it_timer); |
| } |
| |
| /* |
| * This function is exported for use by the signal deliver code. It is |
| * called just prior to the info block being released and passes that |
| * block to us. It's function is to update the overrun entry AND to |
| * restart the timer. It should only be called if the timer is to be |
| * restarted (i.e. we have flagged this in the sys_private entry of the |
| * info block). |
| * |
| * To protect aginst the timer going away while the interrupt is queued, |
| * we require that the it_requeue_pending flag be set. |
| */ |
| void do_schedule_next_timer(struct siginfo *info) |
| { |
| struct k_itimer *timr; |
| unsigned long flags; |
| |
| timr = lock_timer(info->si_tid, &flags); |
| |
| if (!timr || timr->it_requeue_pending != info->si_sys_private) |
| goto exit; |
| |
| schedule_next_timer(timr); |
| info->si_overrun = timr->it_overrun_last; |
| exit: |
| if (timr) |
| unlock_timer(timr, flags); |
| } |
| |
| /* |
| * Notify the task and set up the timer for the next expiration (if |
| * applicable). This function requires that the k_itimer structure |
| * it_lock is taken. This code will requeue the timer only if we get |
| * either an error return or a flag (ret > 0) from send_seg_info |
| * indicating that the signal was either not queued or was queued |
| * without an info block. In this case, we will not get a call back to |
| * do_schedule_next_timer() so we do it here. This should be rare... |
| |
| * An interesting problem can occur if, while a signal, and thus a call |
| * back is pending, the timer is rearmed, i.e. stopped and restarted. |
| * We then need to sort out the call back and do the right thing. What |
| * we do is to put a counter in the info block and match it with the |
| * timers copy on the call back. If they don't match, we just ignore |
| * the call back. The counter is local to the timer and we use odd to |
| * indicate a call back is pending. Note that we do allow the timer to |
| * be deleted while a signal is pending. The standard says we can |
| * allow that signal to be delivered, and we do. |
| */ |
| |
| static void timer_notify_task(struct k_itimer *timr) |
| { |
| struct siginfo info; |
| int ret; |
| |
| memset(&info, 0, sizeof (info)); |
| |
| /* Send signal to the process that owns this timer. */ |
| info.si_signo = timr->it_sigev_signo; |
| info.si_errno = 0; |
| info.si_code = SI_TIMER; |
| info.si_tid = timr->it_id; |
| info.si_value = timr->it_sigev_value; |
| if (timr->it_incr) |
| info.si_sys_private = ++timr->it_requeue_pending; |
| |
| if (timr->it_sigev_notify & SIGEV_THREAD_ID & MIPS_SIGEV) |
| ret = send_sig_info(info.si_signo, &info, timr->it_process); |
| else |
| ret = send_group_sig_info(info.si_signo, &info, |
| timr->it_process); |
| switch (ret) { |
| |
| default: |
| /* |
| * Signal was not sent. May or may not need to |
| * restart the timer. |
| */ |
| printk(KERN_WARNING "sending signal failed: %d\n", ret); |
| case 1: |
| /* |
| * signal was not sent because of sig_ignor or, |
| * possibly no queue memory OR will be sent but, |
| * we will not get a call back to restart it AND |
| * it should be restarted. |
| */ |
| schedule_next_timer(timr); |
| case 0: |
| /* |
| * all's well new signal queued |
| */ |
| break; |
| } |
| } |
| |
| /* |
| * This function gets called when a POSIX.1b interval timer expires. It |
| * is used as a callback from the kernel internal timer. The |
| * run_timer_list code ALWAYS calls with interrutps on. |
| */ |
| static void posix_timer_fn(unsigned long __data) |
| { |
| struct k_itimer *timr = (struct k_itimer *) __data; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&timr->it_lock, flags); |
| set_timer_inactive(timr); |
| timer_notify_task(timr); |
| unlock_timer(timr, flags); |
| } |
| |
| |
| static inline struct task_struct * good_sigevent(sigevent_t * event) |
| { |
| struct task_struct *rtn = current; |
| |
| if ((event->sigev_notify & SIGEV_THREAD_ID & MIPS_SIGEV) && |
| (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) || |
| rtn->tgid != current->tgid)) |
| return NULL; |
| |
| if ((event->sigev_notify & SIGEV_SIGNAL & MIPS_SIGEV) && |
| ((unsigned) (event->sigev_signo > SIGRTMAX))) |
| return NULL; |
| |
| if (event->sigev_notify & ~(SIGEV_SIGNAL | SIGEV_THREAD_ID)) |
| return NULL; |
| |
| return rtn; |
| } |
| |
| void register_posix_clock(int clock_id, struct k_clock *new_clock) |
| { |
| if ((unsigned) clock_id >= MAX_CLOCKS) { |
| printk("POSIX clock register failed for clock_id %d\n", |
| clock_id); |
| return; |
| } |
| posix_clocks[clock_id] = *new_clock; |
| } |
| |
| static struct k_itimer * alloc_posix_timer(void) |
| { |
| struct k_itimer *tmr; |
| tmr = kmem_cache_alloc(posix_timers_cache, GFP_KERNEL); |
| memset(tmr, 0, sizeof (struct k_itimer)); |
| |
| return tmr; |
| } |
| |
| static void release_posix_timer(struct k_itimer *tmr) |
| { |
| if (tmr->it_id != -1) { |
| spin_lock_irq(&idr_lock); |
| idr_remove(&posix_timers_id, tmr->it_id); |
| spin_unlock_irq(&idr_lock); |
| } |
| kmem_cache_free(posix_timers_cache, tmr); |
| } |
| |
| /* Create a POSIX.1b interval timer. */ |
| |
| asmlinkage long |
| sys_timer_create(clockid_t which_clock, |
| struct sigevent __user *timer_event_spec, |
| timer_t __user * created_timer_id) |
| { |
| int error = 0; |
| struct k_itimer *new_timer = NULL; |
| timer_t new_timer_id; |
| struct task_struct *process = 0; |
| sigevent_t event; |
| |
| if ((unsigned) which_clock >= MAX_CLOCKS || |
| !posix_clocks[which_clock].res) |
| return -EINVAL; |
| |
| new_timer = alloc_posix_timer(); |
| if (unlikely(!new_timer)) |
| return -EAGAIN; |
| |
| spin_lock_init(&new_timer->it_lock); |
| do { |
| if (unlikely(!idr_pre_get(&posix_timers_id))) { |
| error = -EAGAIN; |
| new_timer_id = (timer_t)-1; |
| goto out; |
| } |
| spin_lock_irq(&idr_lock); |
| new_timer_id = (timer_t) idr_get_new(&posix_timers_id, |
| (void *) new_timer); |
| spin_unlock_irq(&idr_lock); |
| } while (unlikely(new_timer_id == -1)); |
| |
| new_timer->it_id = new_timer_id; |
| /* |
| * return the timer_id now. The next step is hard to |
| * back out if there is an error. |
| */ |
| if (copy_to_user(created_timer_id, |
| &new_timer_id, sizeof (new_timer_id))) { |
| error = -EFAULT; |
| goto out; |
| } |
| if (timer_event_spec) { |
| if (copy_from_user(&event, timer_event_spec, sizeof (event))) { |
| error = -EFAULT; |
| goto out; |
| } |
| read_lock(&tasklist_lock); |
| if ((process = good_sigevent(&event))) { |
| /* |
| * We may be setting up this process for another |
| * thread. It may be exiting. To catch this |
| * case the we check the PF_EXITING flag. If |
| * the flag is not set, the task_lock will catch |
| * him before it is too late (in exit_itimers). |
| * |
| * The exec case is a bit more invloved but easy |
| * to code. If the process is in our thread |
| * group (and it must be or we would not allow |
| * it here) and is doing an exec, it will cause |
| * us to be killed. In this case it will wait |
| * for us to die which means we can finish this |
| * linkage with our last gasp. I.e. no code :) |
| */ |
| task_lock(process); |
| if (!(process->flags & PF_EXITING)) { |
| list_add(&new_timer->list, |
| &process->posix_timers); |
| task_unlock(process); |
| } else { |
| task_unlock(process); |
| process = 0; |
| } |
| } |
| read_unlock(&tasklist_lock); |
| if (!process) { |
| error = -EINVAL; |
| goto out; |
| } |
| new_timer->it_sigev_notify = event.sigev_notify; |
| new_timer->it_sigev_signo = event.sigev_signo; |
| new_timer->it_sigev_value = event.sigev_value; |
| } else { |
| new_timer->it_sigev_notify = SIGEV_SIGNAL; |
| new_timer->it_sigev_signo = SIGALRM; |
| new_timer->it_sigev_value.sival_int = new_timer->it_id; |
| process = current; |
| task_lock(process); |
| list_add(&new_timer->list, &process->posix_timers); |
| task_unlock(process); |
| } |
| |
| new_timer->it_clock = which_clock; |
| new_timer->it_incr = 0; |
| new_timer->it_overrun = -1; |
| init_timer(&new_timer->it_timer); |
| new_timer->it_timer.expires = 0; |
| new_timer->it_timer.data = (unsigned long) new_timer; |
| new_timer->it_timer.function = posix_timer_fn; |
| set_timer_inactive(new_timer); |
| |
| /* |
| * Once we set the process, it can be found so do it last... |
| */ |
| new_timer->it_process = process; |
| out: |
| if (error) |
| release_posix_timer(new_timer); |
| |
| return error; |
| } |
| |
| /* |
| * good_timespec |
| * |
| * This function checks the elements of a timespec structure. |
| * |
| * Arguments: |
| * ts : Pointer to the timespec structure to check |
| * |
| * Return value: |
| * If a NULL pointer was passed in, or the tv_nsec field was less than 0 |
| * or greater than NSEC_PER_SEC, or the tv_sec field was less than 0, |
| * this function returns 0. Otherwise it returns 1. |
| */ |
| static int good_timespec(const struct timespec *ts) |
| { |
| if ((!ts) || (ts->tv_sec < 0) || |
| ((unsigned) ts->tv_nsec >= NSEC_PER_SEC)) |
| return 0; |
| return 1; |
| } |
| |
| static inline void unlock_timer(struct k_itimer *timr, unsigned long flags) |
| { |
| spin_unlock_irqrestore(&timr->it_lock, flags); |
| } |
| |
| /* |
| * Locking issues: We need to protect the result of the id look up until |
| * we get the timer locked down so it is not deleted under us. The |
| * removal is done under the idr spinlock so we use that here to bridge |
| * the find to the timer lock. To avoid a dead lock, the timer id MUST |
| * be release with out holding the timer lock. |
| */ |
| static struct k_itimer * lock_timer(timer_t timer_id, unsigned long *flags) |
| { |
| struct k_itimer *timr; |
| /* |
| * Watch out here. We do a irqsave on the idr_lock and pass the |
| * flags part over to the timer lock. Must not let interrupts in |
| * while we are moving the lock. |
| */ |
| |
| spin_lock_irqsave(&idr_lock, *flags); |
| timr = (struct k_itimer *) idr_find(&posix_timers_id, (int) timer_id); |
| if (timr) { |
| spin_lock(&timr->it_lock); |
| spin_unlock(&idr_lock); |
| |
| if ((timr->it_id != timer_id) || !(timr->it_process) || |
| timr->it_process->tgid != current->tgid) { |
| unlock_timer(timr, *flags); |
| timr = NULL; |
| } |
| } else |
| spin_unlock_irqrestore(&idr_lock, *flags); |
| |
| return timr; |
| } |
| |
| /* |
| * Get the time remaining on a POSIX.1b interval timer. This function |
| * is ALWAYS called with spin_lock_irq on the timer, thus it must not |
| * mess with irq. |
| * |
| * We have a couple of messes to clean up here. First there is the case |
| * of a timer that has a requeue pending. These timers should appear to |
| * be in the timer list with an expiry as if we were to requeue them |
| * now. |
| * |
| * The second issue is the SIGEV_NONE timer which may be active but is |
| * not really ever put in the timer list (to save system resources). |
| * This timer may be expired, and if so, we will do it here. Otherwise |
| * it is the same as a requeue pending timer WRT to what we should |
| * report. |
| */ |
| void inline |
| do_timer_gettime(struct k_itimer *timr, struct itimerspec *cur_setting) |
| { |
| unsigned long expires; |
| struct now_struct now; |
| |
| do |
| expires = timr->it_timer.expires; |
| while ((volatile long) (timr->it_timer.expires) != expires); |
| |
| posix_get_now(&now); |
| |
| if (expires && (timr->it_sigev_notify & SIGEV_NONE) && !timr->it_incr && |
| posix_time_before(&timr->it_timer, &now)) |
| timr->it_timer.expires = expires = 0; |
| if (expires) { |
| if (timr->it_requeue_pending & REQUEUE_PENDING || |
| (timr->it_sigev_notify & SIGEV_NONE)) |
| while (posix_time_before(&timr->it_timer, &now)) |
| posix_bump_timer(timr); |
| else |
| if (!timer_pending(&timr->it_timer)) |
| expires = 0; |
| if (expires) |
| expires -= now.jiffies; |
| } |
| jiffies_to_timespec(expires, &cur_setting->it_value); |
| jiffies_to_timespec(timr->it_incr, &cur_setting->it_interval); |
| |
| if (cur_setting->it_value.tv_sec < 0) { |
| cur_setting->it_value.tv_nsec = 1; |
| cur_setting->it_value.tv_sec = 0; |
| } |
| } |
| |
| /* Get the time remaining on a POSIX.1b interval timer. */ |
| asmlinkage long |
| sys_timer_gettime(timer_t timer_id, struct itimerspec __user *setting) |
| { |
| struct k_itimer *timr; |
| struct itimerspec cur_setting; |
| unsigned long flags; |
| |
| timr = lock_timer(timer_id, &flags); |
| if (!timr) |
| return -EINVAL; |
| |
| p_timer_get(&posix_clocks[timr->it_clock], timr, &cur_setting); |
| |
| unlock_timer(timr, flags); |
| |
| if (copy_to_user(setting, &cur_setting, sizeof (cur_setting))) |
| return -EFAULT; |
| |
| return 0; |
| } |
| /* |
| * Get the number of overruns of a POSIX.1b interval timer. This is to |
| * be the overrun of the timer last delivered. At the same time we are |
| * accumulating overruns on the next timer. The overrun is frozen when |
| * the signal is delivered, either at the notify time (if the info block |
| * is not queued) or at the actual delivery time (as we are informed by |
| * the call back to do_schedule_next_timer(). So all we need to do is |
| * to pick up the frozen overrun. |
| */ |
| |
| asmlinkage long |
| sys_timer_getoverrun(timer_t timer_id) |
| { |
| struct k_itimer *timr; |
| int overrun; |
| long flags; |
| |
| timr = lock_timer(timer_id, &flags); |
| if (!timr) |
| return -EINVAL; |
| |
| overrun = timr->it_overrun_last; |
| unlock_timer(timr, flags); |
| |
| return overrun; |
| } |
| /* |
| * Adjust for absolute time |
| * |
| * If absolute time is given and it is not CLOCK_MONOTONIC, we need to |
| * adjust for the offset between the timer clock (CLOCK_MONOTONIC) and |
| * what ever clock he is using. |
| * |
| * If it is relative time, we need to add the current (CLOCK_MONOTONIC) |
| * time to it to get the proper time for the timer. |
| */ |
| static int adjust_abs_time(struct k_clock *clock, struct timespec *tp, int abs) |
| { |
| struct timespec now; |
| struct timespec oc; |
| do_posix_clock_monotonic_gettime(&now); |
| |
| if (!abs || (posix_clocks[CLOCK_MONOTONIC].clock_get != |
| clock->clock_get)) { |
| if (abs) |
| do_posix_gettime(clock, &oc); |
| else |
| oc.tv_nsec = oc.tv_sec = 0; |
| |
| tp->tv_sec += now.tv_sec - oc.tv_sec; |
| tp->tv_nsec += now.tv_nsec - oc.tv_nsec; |
| |
| /* |
| * Normalize... |
| */ |
| if ((tp->tv_nsec - NSEC_PER_SEC) >= 0) { |
| tp->tv_nsec -= NSEC_PER_SEC; |
| tp->tv_sec++; |
| } |
| if ((tp->tv_nsec) < 0) { |
| tp->tv_nsec += NSEC_PER_SEC; |
| tp->tv_sec--; |
| } |
| } |
| /* |
| * Check if the requested time is prior to now (if so set now) or |
| * is more than the timer code can handle (if so we error out). |
| * The (unsigned) catches the case of prior to "now" with the same |
| * test. Only on failure do we sort out what happened, and then |
| * we use the (unsigned) to error out negative seconds. |
| */ |
| if ((unsigned) (tp->tv_sec - now.tv_sec) > (MAX_JIFFY_OFFSET / HZ)) { |
| if ((unsigned) tp->tv_sec < now.tv_sec) { |
| tp->tv_sec = now.tv_sec; |
| tp->tv_nsec = now.tv_nsec; |
| } else |
| /* |
| * This is a considered response, not exactly in |
| * line with the standard (in fact it is silent on |
| * possible overflows). We assume such a large |
| * value is ALMOST always a programming error and |
| * try not to compound it by setting a really dumb |
| * value. |
| */ |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| /* Set a POSIX.1b interval timer. */ |
| /* timr->it_lock is taken. */ |
| static inline int |
| do_timer_settime(struct k_itimer *timr, int flags, |
| struct itimerspec *new_setting, struct itimerspec *old_setting) |
| { |
| struct k_clock *clock = &posix_clocks[timr->it_clock]; |
| |
| if (old_setting) |
| do_timer_gettime(timr, old_setting); |
| |
| /* disable the timer */ |
| timr->it_incr = 0; |
| /* |
| * careful here. If smp we could be in the "fire" routine which will |
| * be spinning as we hold the lock. But this is ONLY an SMP issue. |
| */ |
| #ifdef CONFIG_SMP |
| if (timer_active(timr) && !del_timer(&timr->it_timer)) |
| /* |
| * It can only be active if on an other cpu. Since |
| * we have cleared the interval stuff above, it should |
| * clear once we release the spin lock. Of course once |
| * we do that anything could happen, including the |
| * complete melt down of the timer. So return with |
| * a "retry" exit status. |
| */ |
| return TIMER_RETRY; |
| |
| set_timer_inactive(timr); |
| #else |
| del_timer(&timr->it_timer); |
| #endif |
| timr->it_requeue_pending = (timr->it_requeue_pending + 2) & |
| ~REQUEUE_PENDING; |
| timr->it_overrun_last = 0; |
| timr->it_overrun = -1; |
| /* |
| *switch off the timer when it_value is zero |
| */ |
| if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) { |
| timr->it_timer.expires = 0; |
| return 0; |
| } |
| |
| if ((flags & TIMER_ABSTIME) && |
| (clock->clock_get != do_posix_clock_monotonic_gettime)) |
| // FIXME: what is this? |
| ; |
| if (adjust_abs_time(clock, |
| &new_setting->it_value, flags & TIMER_ABSTIME)) |
| return -EINVAL; |
| tstotimer(new_setting, timr); |
| |
| /* |
| * For some reason the timer does not fire immediately if expires is |
| * equal to jiffies, so the timer notify function is called directly. |
| * We do not even queue SIGEV_NONE timers! |
| */ |
| if (!(timr->it_sigev_notify & SIGEV_NONE)) { |
| if (timr->it_timer.expires == jiffies) |
| timer_notify_task(timr); |
| else |
| add_timer(&timr->it_timer); |
| } |
| return 0; |
| } |
| |
| /* Set a POSIX.1b interval timer */ |
| asmlinkage long |
| sys_timer_settime(timer_t timer_id, int flags, |
| const struct itimerspec __user *new_setting, |
| struct itimerspec __user *old_setting) |
| { |
| struct k_itimer *timr; |
| struct itimerspec new_spec, old_spec; |
| int error = 0; |
| long flag; |
| struct itimerspec *rtn = old_setting ? &old_spec : NULL; |
| |
| if (!new_setting) |
| return -EINVAL; |
| |
| if (copy_from_user(&new_spec, new_setting, sizeof (new_spec))) |
| return -EFAULT; |
| |
| if ((!good_timespec(&new_spec.it_interval)) || |
| (!good_timespec(&new_spec.it_value))) |
| return -EINVAL; |
| retry: |
| timr = lock_timer(timer_id, &flag); |
| if (!timr) |
| return -EINVAL; |
| |
| if (!posix_clocks[timr->it_clock].timer_set) |
| error = do_timer_settime(timr, flags, &new_spec, rtn); |
| else |
| error = posix_clocks[timr->it_clock].timer_set(timr, |
| flags, |
| &new_spec, rtn); |
| unlock_timer(timr, flag); |
| if (error == TIMER_RETRY) { |
| rtn = NULL; // We already got the old time... |
| goto retry; |
| } |
| |
| if (old_setting && !error && copy_to_user(old_setting, |
| &old_spec, sizeof (old_spec))) |
| error = -EFAULT; |
| |
| return error; |
| } |
| |
| static inline int do_timer_delete(struct k_itimer *timer) |
| { |
| timer->it_incr = 0; |
| #ifdef CONFIG_SMP |
| if (timer_active(timer) && !del_timer(&timer->it_timer)) |
| /* |
| * It can only be active if on an other cpu. Since |
| * we have cleared the interval stuff above, it should |
| * clear once we release the spin lock. Of course once |
| * we do that anything could happen, including the |
| * complete melt down of the timer. So return with |
| * a "retry" exit status. |
| */ |
| return TIMER_RETRY; |
| #else |
| del_timer(&timer->it_timer); |
| #endif |
| return 0; |
| } |
| |
| /* Delete a POSIX.1b interval timer. */ |
| asmlinkage long |
| sys_timer_delete(timer_t timer_id) |
| { |
| struct k_itimer *timer; |
| long flags; |
| |
| #ifdef CONFIG_SMP |
| int error; |
| retry_delete: |
| #endif |
| timer = lock_timer(timer_id, &flags); |
| if (!timer) |
| return -EINVAL; |
| |
| #ifdef CONFIG_SMP |
| error = p_timer_del(&posix_clocks[timer->it_clock], timer); |
| |
| if (error == TIMER_RETRY) { |
| unlock_timer(timer, flags); |
| goto retry_delete; |
| } |
| #else |
| p_timer_del(&posix_clocks[timer->it_clock], timer); |
| #endif |
| task_lock(timer->it_process); |
| list_del(&timer->list); |
| task_unlock(timer->it_process); |
| /* |
| * This keeps any tasks waiting on the spin lock from thinking |
| * they got something (see the lock code above). |
| */ |
| timer->it_process = NULL; |
| unlock_timer(timer, flags); |
| release_posix_timer(timer); |
| return 0; |
| } |
| /* |
| * return timer owned by the process, used by exit_itimers |
| */ |
| static inline void itimer_delete(struct k_itimer *timer) |
| { |
| if (sys_timer_delete(timer->it_id)) |
| BUG(); |
| } |
| /* |
| * This is exported to exit and exec |
| */ |
| void exit_itimers(struct task_struct *tsk) |
| { |
| struct k_itimer *tmr; |
| |
| task_lock(tsk); |
| while (!list_empty(&tsk->posix_timers)) { |
| tmr = list_entry(tsk->posix_timers.next, struct k_itimer, list); |
| task_unlock(tsk); |
| itimer_delete(tmr); |
| task_lock(tsk); |
| } |
| task_unlock(tsk); |
| } |
| |
| /* |
| * And now for the "clock" calls |
| * |
| * These functions are called both from timer functions (with the timer |
| * spin_lock_irq() held and from clock calls with no locking. They must |
| * use the save flags versions of locks. |
| */ |
| static int do_posix_gettime(struct k_clock *clock, struct timespec *tp) |
| { |
| if (clock->clock_get) |
| return clock->clock_get(tp); |
| |
| do_gettimeofday((struct timeval *) tp); |
| tp->tv_nsec *= NSEC_PER_USEC; |
| return 0; |
| } |
| |
| /* |
| * We do ticks here to avoid the irq lock ( they take sooo long). |
| * The seqlock is great here. Since we a reader, we don't really care |
| * if we are interrupted since we don't take lock that will stall us or |
| * any other cpu. Voila, no irq lock is needed. |
| * |
| * Note also that the while loop assures that the sub_jiff_offset |
| * will be less than a jiffie, thus no need to normalize the result. |
| * Well, not really, if called with ints off :( |
| * |
| * HELP, this code should make an attempt at resolution beyond the |
| * jiffie. Trouble is this is "arch" dependent... |
| */ |
| |
| int do_posix_clock_monotonic_gettime(struct timespec *tp) |
| { |
| long sub_sec; |
| u64 jiffies_64_f; |
| |
| #if (BITS_PER_LONG > 32) |
| jiffies_64_f = jiffies_64; |
| #else |
| unsigned int seq; |
| |
| do { |
| seq = read_seqbegin(&xtime_lock); |
| jiffies_64_f = jiffies_64; |
| |
| } while (read_seqretry(&xtime_lock, seq)); |
| #endif |
| tp->tv_sec = div_long_long_rem(jiffies_64_f, HZ, &sub_sec); |
| tp->tv_nsec = sub_sec * (NSEC_PER_SEC / HZ); |
| |
| return 0; |
| } |
| |
| int do_posix_clock_monotonic_settime(struct timespec *tp) |
| { |
| return -EINVAL; |
| } |
| |
| asmlinkage long |
| sys_clock_settime(clockid_t which_clock, const struct timespec __user *tp) |
| { |
| struct timespec new_tp; |
| |
| if ((unsigned) which_clock >= MAX_CLOCKS || |
| !posix_clocks[which_clock].res) |
| return -EINVAL; |
| if (copy_from_user(&new_tp, tp, sizeof (*tp))) |
| return -EFAULT; |
| if (posix_clocks[which_clock].clock_set) |
| return posix_clocks[which_clock].clock_set(&new_tp); |
| |
| new_tp.tv_nsec /= NSEC_PER_USEC; |
| return do_sys_settimeofday((struct timeval *) &new_tp, NULL); |
| } |
| |
| asmlinkage long |
| sys_clock_gettime(clockid_t which_clock, struct timespec __user *tp) |
| { |
| struct timespec rtn_tp; |
| int error = 0; |
| |
| if ((unsigned) which_clock >= MAX_CLOCKS || |
| !posix_clocks[which_clock].res) |
| return -EINVAL; |
| |
| error = do_posix_gettime(&posix_clocks[which_clock], &rtn_tp); |
| |
| if (!error && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) |
| error = -EFAULT; |
| |
| return error; |
| |
| } |
| |
| asmlinkage long |
| sys_clock_getres(clockid_t which_clock, struct timespec __user *tp) |
| { |
| struct timespec rtn_tp; |
| |
| if ((unsigned) which_clock >= MAX_CLOCKS || |
| !posix_clocks[which_clock].res) |
| return -EINVAL; |
| |
| rtn_tp.tv_sec = 0; |
| rtn_tp.tv_nsec = posix_clocks[which_clock].res; |
| if (tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) |
| return -EFAULT; |
| |
| return 0; |
| |
| } |
| |
| static void nanosleep_wake_up(unsigned long __data) |
| { |
| struct task_struct *p = (struct task_struct *) __data; |
| |
| wake_up_process(p); |
| } |
| |
| /* |
| * The standard says that an absolute nanosleep call MUST wake up at |
| * the requested time in spite of clock settings. Here is what we do: |
| * For each nanosleep call that needs it (only absolute and not on |
| * CLOCK_MONOTONIC* (as it can not be set)) we thread a little structure |
| * into the "nanosleep_abs_list". All we need is the task_struct pointer. |
| * When ever the clock is set we just wake up all those tasks. The rest |
| * is done by the while loop in clock_nanosleep(). |
| * |
| * On locking, clock_was_set() is called from update_wall_clock which |
| * holds (or has held for it) a write_lock_irq( xtime_lock) and is |
| * called from the timer bh code. Thus we need the irq save locks. |
| */ |
| |
| static DECLARE_WAIT_QUEUE_HEAD(nanosleep_abs_wqueue); |
| |
| void clock_was_set(void) |
| { |
| wake_up_all(&nanosleep_abs_wqueue); |
| } |
| |
| long clock_nanosleep_restart(struct restart_block *restart_block); |
| |
| extern long do_clock_nanosleep(clockid_t which_clock, int flags, |
| struct timespec *t); |
| |
| #ifdef FOLD_NANO_SLEEP_INTO_CLOCK_NANO_SLEEP |
| |
| asmlinkage long |
| sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) |
| { |
| struct timespec t; |
| long ret; |
| |
| if (copy_from_user(&t, rqtp, sizeof (t))) |
| return -EFAULT; |
| |
| if ((unsigned) t.tv_nsec >= NSEC_PER_SEC || t.tv_sec < 0) |
| return -EINVAL; |
| |
| ret = do_clock_nanosleep(CLOCK_REALTIME, 0, &t); |
| |
| if (ret == -ERESTART_RESTARTBLOCK && rmtp && |
| copy_to_user(rmtp, &t, sizeof (t))) |
| return -EFAULT; |
| return ret; |
| } |
| #endif // ! FOLD_NANO_SLEEP_INTO_CLOCK_NANO_SLEEP |
| |
| asmlinkage long |
| sys_clock_nanosleep(clockid_t which_clock, int flags, |
| const struct timespec __user *rqtp, |
| struct timespec __user *rmtp) |
| { |
| struct timespec t; |
| int ret; |
| |
| if ((unsigned) which_clock >= MAX_CLOCKS || |
| !posix_clocks[which_clock].res) |
| return -EINVAL; |
| |
| if (copy_from_user(&t, rqtp, sizeof (struct timespec))) |
| return -EFAULT; |
| |
| if ((unsigned) t.tv_nsec >= NSEC_PER_SEC || t.tv_sec < 0) |
| return -EINVAL; |
| |
| ret = do_clock_nanosleep(which_clock, flags, &t); |
| |
| if ((ret == -ERESTART_RESTARTBLOCK) && rmtp && |
| copy_to_user(rmtp, &t, sizeof (t))) |
| return -EFAULT; |
| return ret; |
| } |
| |
| long |
| do_clock_nanosleep(clockid_t which_clock, int flags, struct timespec *tsave) |
| { |
| struct timespec t; |
| struct timer_list new_timer; |
| DECLARE_WAITQUEUE(abs_wqueue, current); |
| u64 rq_time = 0; |
| s64 left; |
| int abs; |
| struct restart_block *restart_block = |
| ¤t_thread_info()->restart_block; |
| |
| abs_wqueue.flags = 0; |
| init_timer(&new_timer); |
| new_timer.expires = 0; |
| new_timer.data = (unsigned long) current; |
| new_timer.function = nanosleep_wake_up; |
| abs = flags & TIMER_ABSTIME; |
| |
| if (restart_block->fn == clock_nanosleep_restart) { |
| /* |
| * Interrupted by a non-delivered signal, pick up remaining |
| * time and continue. |
| */ |
| restart_block->fn = do_no_restart_syscall; |
| |
| rq_time = restart_block->arg3; |
| rq_time = (rq_time << 32) + restart_block->arg2; |
| if (!rq_time) |
| return -EINTR; |
| left = rq_time - get_jiffies_64(); |
| if (left <= 0LL) |
| return 0; /* Already passed */ |
| } |
| |
| if (abs && (posix_clocks[which_clock].clock_get != |
| posix_clocks[CLOCK_MONOTONIC].clock_get)) |
| add_wait_queue(&nanosleep_abs_wqueue, &abs_wqueue); |
| |
| do { |
| t = *tsave; |
| if (abs || !rq_time) { |
| adjust_abs_time(&posix_clocks[which_clock], &t, abs); |
| tstojiffie(&t, posix_clocks[which_clock].res, &rq_time); |
| } |
| |
| left = rq_time - get_jiffies_64(); |
| if (left >= MAX_JIFFY_OFFSET) |
| left = MAX_JIFFY_OFFSET; |
| if (left < 0) |
| break; |
| |
| new_timer.expires = jiffies + left; |
| __set_current_state(TASK_INTERRUPTIBLE); |
| add_timer(&new_timer); |
| |
| schedule(); |
| |
| del_timer_sync(&new_timer); |
| left = rq_time - get_jiffies_64(); |
| } while (left > 0 && !test_thread_flag(TIF_SIGPENDING)); |
| |
| if (abs_wqueue.task_list.next) |
| finish_wait(&nanosleep_abs_wqueue, &abs_wqueue); |
| |
| if (left > 0) { |
| unsigned long rmd; |
| |
| /* |
| * Always restart abs calls from scratch to pick up any |
| * clock shifting that happened while we are away. |
| */ |
| if (abs) |
| return -ERESTARTNOHAND; |
| |
| tsave->tv_sec = div_long_long_rem(left, HZ, &rmd); |
| tsave->tv_nsec = rmd * (NSEC_PER_SEC / HZ); |
| |
| restart_block->fn = clock_nanosleep_restart; |
| restart_block->arg0 = which_clock; |
| restart_block->arg1 = (unsigned long)tsave; |
| restart_block->arg2 = rq_time & 0xffffffffLL; |
| restart_block->arg3 = rq_time >> 32; |
| |
| return -ERESTART_RESTARTBLOCK; |
| } |
| |
| return 0; |
| } |
| /* |
| * This will restart either clock_nanosleep or clock_nanosleep |
| */ |
| long |
| clock_nanosleep_restart(struct restart_block *restart_block) |
| { |
| struct timespec t; |
| int ret = do_clock_nanosleep(restart_block->arg0, 0, &t); |
| |
| if ((ret == -ERESTART_RESTARTBLOCK) && restart_block->arg1 && |
| copy_to_user((struct timespec __user *)(restart_block->arg1), &t, |
| sizeof (t))) |
| return -EFAULT; |
| return ret; |
| } |