| /* |
| * linux/kernel/hrtimer.c |
| * |
| * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> |
| * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar |
| * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner |
| * |
| * High-resolution kernel timers |
| * |
| * In contrast to the low-resolution timeout API implemented in |
| * kernel/timer.c, hrtimers provide finer resolution and accuracy |
| * depending on system configuration and capabilities. |
| * |
| * These timers are currently used for: |
| * - itimers |
| * - POSIX timers |
| * - nanosleep |
| * - precise in-kernel timing |
| * |
| * Started by: Thomas Gleixner and Ingo Molnar |
| * |
| * 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 |
| */ |
| |
| #include <linux/cpu.h> |
| #include <linux/irq.h> |
| #include <linux/module.h> |
| #include <linux/percpu.h> |
| #include <linux/hrtimer.h> |
| #include <linux/notifier.h> |
| #include <linux/syscalls.h> |
| #include <linux/kallsyms.h> |
| #include <linux/interrupt.h> |
| #include <linux/tick.h> |
| #include <linux/seq_file.h> |
| #include <linux/err.h> |
| #include <linux/debugobjects.h> |
| |
| #include <asm/uaccess.h> |
| |
| /** |
| * ktime_get - get the monotonic time in ktime_t format |
| * |
| * returns the time in ktime_t format |
| */ |
| ktime_t ktime_get(void) |
| { |
| struct timespec now; |
| |
| ktime_get_ts(&now); |
| |
| return timespec_to_ktime(now); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get); |
| |
| /** |
| * ktime_get_real - get the real (wall-) time in ktime_t format |
| * |
| * returns the time in ktime_t format |
| */ |
| ktime_t ktime_get_real(void) |
| { |
| struct timespec now; |
| |
| getnstimeofday(&now); |
| |
| return timespec_to_ktime(now); |
| } |
| |
| 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_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = |
| { |
| |
| .clock_base = |
| { |
| { |
| .index = CLOCK_REALTIME, |
| .get_time = &ktime_get_real, |
| .resolution = KTIME_LOW_RES, |
| }, |
| { |
| .index = CLOCK_MONOTONIC, |
| .get_time = &ktime_get, |
| .resolution = KTIME_LOW_RES, |
| }, |
| } |
| }; |
| |
| /** |
| * ktime_get_ts - get the monotonic clock in timespec format |
| * @ts: pointer to timespec variable |
| * |
| * The function calculates the monotonic clock from the realtime |
| * clock and the wall_to_monotonic offset and stores the result |
| * in normalized timespec format in the variable pointed to by @ts. |
| */ |
| void ktime_get_ts(struct timespec *ts) |
| { |
| struct timespec tomono; |
| unsigned long seq; |
| |
| do { |
| seq = read_seqbegin(&xtime_lock); |
| getnstimeofday(ts); |
| tomono = wall_to_monotonic; |
| |
| } while (read_seqretry(&xtime_lock, seq)); |
| |
| set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, |
| ts->tv_nsec + tomono.tv_nsec); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_ts); |
| |
| /* |
| * Get the coarse grained time at the softirq based on xtime and |
| * wall_to_monotonic. |
| */ |
| static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) |
| { |
| ktime_t xtim, tomono; |
| struct timespec xts, tom; |
| unsigned long seq; |
| |
| do { |
| seq = read_seqbegin(&xtime_lock); |
| xts = current_kernel_time(); |
| tom = wall_to_monotonic; |
| } while (read_seqretry(&xtime_lock, seq)); |
| |
| xtim = timespec_to_ktime(xts); |
| tomono = timespec_to_ktime(tom); |
| base->clock_base[CLOCK_REALTIME].softirq_time = xtim; |
| base->clock_base[CLOCK_MONOTONIC].softirq_time = |
| ktime_add(xtim, tomono); |
| } |
| |
| /* |
| * Functions and macros which are different for UP/SMP systems are kept in a |
| * single place |
| */ |
| #ifdef CONFIG_SMP |
| |
| /* |
| * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock |
| * means that all timers which are tied to this base via timer->base are |
| * locked, and the base itself is locked too. |
| * |
| * So __run_timers/migrate_timers can safely modify all timers which could |
| * be found on the lists/queues. |
| * |
| * When the timer's base is locked, and the timer removed from list, it is |
| * possible to set timer->base = NULL and drop the lock: the timer remains |
| * locked. |
| */ |
| static |
| struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer, |
| unsigned long *flags) |
| { |
| struct hrtimer_clock_base *base; |
| |
| for (;;) { |
| base = timer->base; |
| if (likely(base != NULL)) { |
| spin_lock_irqsave(&base->cpu_base->lock, *flags); |
| if (likely(base == timer->base)) |
| return base; |
| /* The timer has migrated to another CPU: */ |
| spin_unlock_irqrestore(&base->cpu_base->lock, *flags); |
| } |
| cpu_relax(); |
| } |
| } |
| |
| /* |
| * Switch the timer base to the current CPU when possible. |
| */ |
| static inline struct hrtimer_clock_base * |
| switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base) |
| { |
| struct hrtimer_clock_base *new_base; |
| struct hrtimer_cpu_base *new_cpu_base; |
| |
| new_cpu_base = &__get_cpu_var(hrtimer_bases); |
| new_base = &new_cpu_base->clock_base[base->index]; |
| |
| if (base != new_base) { |
| /* |
| * We are trying to schedule the timer on the local CPU. |
| * However we can't change timer's base while it is running, |
| * so we keep it on the same CPU. No hassle vs. reprogramming |
| * the event source in the high resolution case. The softirq |
| * code will take care of this when the timer function has |
| * completed. There is no conflict as we hold the lock until |
| * the timer is enqueued. |
| */ |
| if (unlikely(hrtimer_callback_running(timer))) |
| return base; |
| |
| /* See the comment in lock_timer_base() */ |
| timer->base = NULL; |
| spin_unlock(&base->cpu_base->lock); |
| spin_lock(&new_base->cpu_base->lock); |
| timer->base = new_base; |
| } |
| return new_base; |
| } |
| |
| #else /* CONFIG_SMP */ |
| |
| static inline struct hrtimer_clock_base * |
| lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) |
| { |
| struct hrtimer_clock_base *base = timer->base; |
| |
| spin_lock_irqsave(&base->cpu_base->lock, *flags); |
| |
| return base; |
| } |
| |
| # define switch_hrtimer_base(t, b) (b) |
| |
| #endif /* !CONFIG_SMP */ |
| |
| /* |
| * Functions for the union type storage format of ktime_t which are |
| * too large for inlining: |
| */ |
| #if BITS_PER_LONG < 64 |
| # ifndef CONFIG_KTIME_SCALAR |
| /** |
| * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable |
| * @kt: addend |
| * @nsec: the scalar nsec value to add |
| * |
| * Returns the sum of kt and nsec in ktime_t format |
| */ |
| ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) |
| { |
| ktime_t tmp; |
| |
| if (likely(nsec < NSEC_PER_SEC)) { |
| tmp.tv64 = nsec; |
| } else { |
| unsigned long rem = do_div(nsec, NSEC_PER_SEC); |
| |
| tmp = ktime_set((long)nsec, rem); |
| } |
| |
| return ktime_add(kt, tmp); |
| } |
| |
| EXPORT_SYMBOL_GPL(ktime_add_ns); |
| |
| /** |
| * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable |
| * @kt: minuend |
| * @nsec: the scalar nsec value to subtract |
| * |
| * Returns the subtraction of @nsec from @kt in ktime_t format |
| */ |
| ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec) |
| { |
| ktime_t tmp; |
| |
| if (likely(nsec < NSEC_PER_SEC)) { |
| tmp.tv64 = nsec; |
| } else { |
| unsigned long rem = do_div(nsec, NSEC_PER_SEC); |
| |
| tmp = ktime_set((long)nsec, rem); |
| } |
| |
| return ktime_sub(kt, tmp); |
| } |
| |
| EXPORT_SYMBOL_GPL(ktime_sub_ns); |
| # endif /* !CONFIG_KTIME_SCALAR */ |
| |
| /* |
| * Divide a ktime value by a nanosecond value |
| */ |
| u64 ktime_divns(const ktime_t kt, s64 div) |
| { |
| u64 dclc, inc, dns; |
| int sft = 0; |
| |
| dclc = dns = ktime_to_ns(kt); |
| inc = div; |
| /* Make sure the divisor is less than 2^32: */ |
| while (div >> 32) { |
| sft++; |
| div >>= 1; |
| } |
| dclc >>= sft; |
| do_div(dclc, (unsigned long) div); |
| |
| return dclc; |
| } |
| #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; |
| } |
| |
| #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
| |
| static struct debug_obj_descr hrtimer_debug_descr; |
| |
| /* |
| * fixup_init is called when: |
| * - an active object is initialized |
| */ |
| static int hrtimer_fixup_init(void *addr, enum debug_obj_state state) |
| { |
| struct hrtimer *timer = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_ACTIVE: |
| hrtimer_cancel(timer); |
| debug_object_init(timer, &hrtimer_debug_descr); |
| return 1; |
| default: |
| return 0; |
| } |
| } |
| |
| /* |
| * fixup_activate is called when: |
| * - an active object is activated |
| * - an unknown object is activated (might be a statically initialized object) |
| */ |
| static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state) |
| { |
| switch (state) { |
| |
| case ODEBUG_STATE_NOTAVAILABLE: |
| WARN_ON_ONCE(1); |
| return 0; |
| |
| case ODEBUG_STATE_ACTIVE: |
| WARN_ON(1); |
| |
| default: |
| return 0; |
| } |
| } |
| |
| /* |
| * fixup_free is called when: |
| * - an active object is freed |
| */ |
| static int hrtimer_fixup_free(void *addr, enum debug_obj_state state) |
| { |
| struct hrtimer *timer = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_ACTIVE: |
| hrtimer_cancel(timer); |
| debug_object_free(timer, &hrtimer_debug_descr); |
| return 1; |
| default: |
| return 0; |
| } |
| } |
| |
| static struct debug_obj_descr hrtimer_debug_descr = { |
| .name = "hrtimer", |
| .fixup_init = hrtimer_fixup_init, |
| .fixup_activate = hrtimer_fixup_activate, |
| .fixup_free = hrtimer_fixup_free, |
| }; |
| |
| static inline void debug_hrtimer_init(struct hrtimer *timer) |
| { |
| debug_object_init(timer, &hrtimer_debug_descr); |
| } |
| |
| static inline void debug_hrtimer_activate(struct hrtimer *timer) |
| { |
| debug_object_activate(timer, &hrtimer_debug_descr); |
| } |
| |
| static inline void debug_hrtimer_deactivate(struct hrtimer *timer) |
| { |
| debug_object_deactivate(timer, &hrtimer_debug_descr); |
| } |
| |
| static inline void debug_hrtimer_free(struct hrtimer *timer) |
| { |
| debug_object_free(timer, &hrtimer_debug_descr); |
| } |
| |
| static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
| enum hrtimer_mode mode); |
| |
| void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id, |
| enum hrtimer_mode mode) |
| { |
| debug_object_init_on_stack(timer, &hrtimer_debug_descr); |
| __hrtimer_init(timer, clock_id, mode); |
| } |
| |
| void destroy_hrtimer_on_stack(struct hrtimer *timer) |
| { |
| debug_object_free(timer, &hrtimer_debug_descr); |
| } |
| |
| #else |
| static inline void debug_hrtimer_init(struct hrtimer *timer) { } |
| static inline void debug_hrtimer_activate(struct hrtimer *timer) { } |
| static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { } |
| #endif |
| |
| /* |
| * Check, whether the timer is on the callback pending list |
| */ |
| static inline int hrtimer_cb_pending(const struct hrtimer *timer) |
| { |
| return timer->state & HRTIMER_STATE_PENDING; |
| } |
| |
| /* |
| * Remove a timer from the callback pending list |
| */ |
| static inline void hrtimer_remove_cb_pending(struct hrtimer *timer) |
| { |
| list_del_init(&timer->cb_entry); |
| } |
| |
| /* High resolution timer related functions */ |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| |
| /* |
| * High resolution timer enabled ? |
| */ |
| static int hrtimer_hres_enabled __read_mostly = 1; |
| |
| /* |
| * Enable / Disable high resolution mode |
| */ |
| static int __init setup_hrtimer_hres(char *str) |
| { |
| if (!strcmp(str, "off")) |
| hrtimer_hres_enabled = 0; |
| else if (!strcmp(str, "on")) |
| hrtimer_hres_enabled = 1; |
| else |
| return 0; |
| return 1; |
| } |
| |
| __setup("highres=", setup_hrtimer_hres); |
| |
| /* |
| * hrtimer_high_res_enabled - query, if the highres mode is enabled |
| */ |
| static inline int hrtimer_is_hres_enabled(void) |
| { |
| return hrtimer_hres_enabled; |
| } |
| |
| /* |
| * Is the high resolution mode active ? |
| */ |
| static inline int hrtimer_hres_active(void) |
| { |
| return __get_cpu_var(hrtimer_bases).hres_active; |
| } |
| |
| /* |
| * Reprogram the event source with checking both queues for the |
| * next event |
| * Called with interrupts disabled and base->lock held |
| */ |
| static void hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base) |
| { |
| int i; |
| struct hrtimer_clock_base *base = cpu_base->clock_base; |
| ktime_t expires; |
| |
| cpu_base->expires_next.tv64 = KTIME_MAX; |
| |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { |
| struct hrtimer *timer; |
| |
| if (!base->first) |
| continue; |
| timer = rb_entry(base->first, struct hrtimer, node); |
| expires = ktime_sub(timer->expires, base->offset); |
| if (expires.tv64 < cpu_base->expires_next.tv64) |
| cpu_base->expires_next = expires; |
| } |
| |
| if (cpu_base->expires_next.tv64 != KTIME_MAX) |
| tick_program_event(cpu_base->expires_next, 1); |
| } |
| |
| /* |
| * Shared reprogramming for clock_realtime and clock_monotonic |
| * |
| * When a timer is enqueued and expires earlier than the already enqueued |
| * timers, we have to check, whether it expires earlier than the timer for |
| * which the clock event device was armed. |
| * |
| * Called with interrupts disabled and base->cpu_base.lock held |
| */ |
| static int hrtimer_reprogram(struct hrtimer *timer, |
| struct hrtimer_clock_base *base) |
| { |
| ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next; |
| 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 |
| * the callback is executed in the hrtimer_interrupt context. The |
| * reprogramming is handled either by the softirq, which called the |
| * callback or at the end of the hrtimer_interrupt. |
| */ |
| 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; |
| |
| /* |
| * Clockevents returns -ETIME, when the event was in the past. |
| */ |
| res = tick_program_event(expires, 0); |
| if (!IS_ERR_VALUE(res)) |
| *expires_next = expires; |
| return res; |
| } |
| |
| |
| /* |
| * Retrigger next event is called after clock was set |
| * |
| * Called with interrupts disabled via on_each_cpu() |
| */ |
| static void retrigger_next_event(void *arg) |
| { |
| struct hrtimer_cpu_base *base; |
| struct timespec realtime_offset; |
| unsigned long seq; |
| |
| if (!hrtimer_hres_active()) |
| return; |
| |
| do { |
| seq = read_seqbegin(&xtime_lock); |
| set_normalized_timespec(&realtime_offset, |
| -wall_to_monotonic.tv_sec, |
| -wall_to_monotonic.tv_nsec); |
| } while (read_seqretry(&xtime_lock, seq)); |
| |
| base = &__get_cpu_var(hrtimer_bases); |
| |
| /* Adjust CLOCK_REALTIME offset */ |
| spin_lock(&base->lock); |
| base->clock_base[CLOCK_REALTIME].offset = |
| timespec_to_ktime(realtime_offset); |
| |
| hrtimer_force_reprogram(base); |
| spin_unlock(&base->lock); |
| } |
| |
| /* |
| * Clock realtime was set |
| * |
| * Change the offset of the realtime clock vs. the monotonic |
| * clock. |
| * |
| * We might have to reprogram the high resolution timer interrupt. On |
| * SMP we call the architecture specific code to retrigger _all_ high |
| * resolution timer interrupts. On UP we just disable interrupts and |
| * call the high resolution interrupt code. |
| */ |
| void clock_was_set(void) |
| { |
| /* Retrigger the CPU local events everywhere */ |
| on_each_cpu(retrigger_next_event, NULL, 0, 1); |
| } |
| |
| /* |
| * During resume we might have to reprogram the high resolution timer |
| * interrupt (on the local CPU): |
| */ |
| void hres_timers_resume(void) |
| { |
| WARN_ON_ONCE(num_online_cpus() > 1); |
| |
| /* Retrigger the CPU local events: */ |
| retrigger_next_event(NULL); |
| } |
| |
| /* |
| * Initialize the high resolution related parts of cpu_base |
| */ |
| static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) |
| { |
| base->expires_next.tv64 = KTIME_MAX; |
| base->hres_active = 0; |
| } |
| |
| /* |
| * Initialize the high resolution related parts of a hrtimer |
| */ |
| static inline void hrtimer_init_timer_hres(struct hrtimer *timer) |
| { |
| } |
| |
| /* |
| * When High resolution timers are active, try to reprogram. Note, that in case |
| * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry |
| * check happens. The timer gets enqueued into the rbtree. The reprogramming |
| * and expiry check is done in the hrtimer_interrupt or in the softirq. |
| */ |
| static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, |
| struct hrtimer_clock_base *base) |
| { |
| if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) { |
| |
| /* Timer is expired, act upon the callback mode */ |
| switch(timer->cb_mode) { |
| case HRTIMER_CB_IRQSAFE_NO_RESTART: |
| debug_hrtimer_deactivate(timer); |
| /* |
| * We can call the callback from here. No restart |
| * happens, so no danger of recursion |
| */ |
| BUG_ON(timer->function(timer) != HRTIMER_NORESTART); |
| return 1; |
| case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: |
| /* |
| * This is solely for the sched tick emulation with |
| * dynamic tick support to ensure that we do not |
| * restart the tick right on the edge and end up with |
| * the tick timer in the softirq ! The calling site |
| * takes care of this. |
| */ |
| debug_hrtimer_deactivate(timer); |
| return 1; |
| case HRTIMER_CB_IRQSAFE: |
| case HRTIMER_CB_SOFTIRQ: |
| /* |
| * Move everything else into the softirq pending list ! |
| */ |
| list_add_tail(&timer->cb_entry, |
| &base->cpu_base->cb_pending); |
| timer->state = HRTIMER_STATE_PENDING; |
| return 1; |
| default: |
| BUG(); |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Switch to high resolution mode |
| */ |
| static int hrtimer_switch_to_hres(void) |
| { |
| int cpu = smp_processor_id(); |
| struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu); |
| unsigned long flags; |
| |
| if (base->hres_active) |
| return 1; |
| |
| local_irq_save(flags); |
| |
| if (tick_init_highres()) { |
| local_irq_restore(flags); |
| printk(KERN_WARNING "Could not switch to high resolution " |
| "mode on CPU %d\n", cpu); |
| return 0; |
| } |
| base->hres_active = 1; |
| base->clock_base[CLOCK_REALTIME].resolution = KTIME_HIGH_RES; |
| base->clock_base[CLOCK_MONOTONIC].resolution = KTIME_HIGH_RES; |
| |
| tick_setup_sched_timer(); |
| |
| /* "Retrigger" the interrupt to get things going */ |
| retrigger_next_event(NULL); |
| local_irq_restore(flags); |
| printk(KERN_DEBUG "Switched to high resolution mode on CPU %d\n", |
| smp_processor_id()); |
| return 1; |
| } |
| |
| static inline void hrtimer_raise_softirq(void) |
| { |
| raise_softirq(HRTIMER_SOFTIRQ); |
| } |
| |
| #else |
| |
| static inline int hrtimer_hres_active(void) { return 0; } |
| static inline int hrtimer_is_hres_enabled(void) { return 0; } |
| static inline int hrtimer_switch_to_hres(void) { return 0; } |
| static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base) { } |
| static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, |
| struct hrtimer_clock_base *base) |
| { |
| return 0; |
| } |
| static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { } |
| static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { } |
| static inline int hrtimer_reprogram(struct hrtimer *timer, |
| struct hrtimer_clock_base *base) |
| { |
| return 0; |
| } |
| static inline void hrtimer_raise_softirq(void) { } |
| |
| #endif /* CONFIG_HIGH_RES_TIMERS */ |
| |
| #ifdef CONFIG_TIMER_STATS |
| void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr) |
| { |
| if (timer->start_site) |
| return; |
| |
| timer->start_site = addr; |
| memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); |
| timer->start_pid = current->pid; |
| } |
| #endif |
| |
| /* |
| * Counterpart to lock_hrtimer_base above: |
| */ |
| static inline |
| void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) |
| { |
| spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags); |
| } |
| |
| /** |
| * hrtimer_forward - forward the timer expiry |
| * @timer: hrtimer to forward |
| * @now: forward past this time |
| * @interval: the interval to forward |
| * |
| * Forward the timer expiry so it will expire in the future. |
| * Returns the number of overruns. |
| */ |
| u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval) |
| { |
| u64 orun = 1; |
| ktime_t delta; |
| |
| delta = ktime_sub(now, timer->expires); |
| |
| if (delta.tv64 < 0) |
| return 0; |
| |
| if (interval.tv64 < timer->base->resolution.tv64) |
| interval.tv64 = timer->base->resolution.tv64; |
| |
| if (unlikely(delta.tv64 >= interval.tv64)) { |
| s64 incr = ktime_to_ns(interval); |
| |
| orun = ktime_divns(delta, incr); |
| timer->expires = ktime_add_ns(timer->expires, incr * orun); |
| if (timer->expires.tv64 > now.tv64) |
| return orun; |
| /* |
| * This (and the ktime_add() below) is the |
| * correction for exact: |
| */ |
| orun++; |
| } |
| timer->expires = ktime_add_safe(timer->expires, interval); |
| |
| return orun; |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_forward); |
| |
| /* |
| * enqueue_hrtimer - internal function to (re)start a timer |
| * |
| * The timer is inserted in expiry order. Insertion into the |
| * red black tree is O(log(n)). Must hold the base lock. |
| */ |
| static void enqueue_hrtimer(struct hrtimer *timer, |
| struct hrtimer_clock_base *base, int reprogram) |
| { |
| struct rb_node **link = &base->active.rb_node; |
| struct rb_node *parent = NULL; |
| struct hrtimer *entry; |
| int leftmost = 1; |
| |
| debug_hrtimer_activate(timer); |
| |
| /* |
| * Find the right place in the rbtree: |
| */ |
| while (*link) { |
| parent = *link; |
| entry = rb_entry(parent, struct hrtimer, node); |
| /* |
| * We dont care about collisions. Nodes with |
| * the same expiry time stay together. |
| */ |
| if (timer->expires.tv64 < entry->expires.tv64) { |
| link = &(*link)->rb_left; |
| } else { |
| link = &(*link)->rb_right; |
| leftmost = 0; |
| } |
| } |
| |
| /* |
| * Insert the timer to the rbtree and check whether it |
| * replaces the first pending timer |
| */ |
| if (leftmost) { |
| /* |
| * Reprogram the clock event device. When the timer is already |
| * expired hrtimer_enqueue_reprogram has either called the |
| * callback or added it to the pending list and raised the |
| * softirq. |
| * |
| * This is a NOP for !HIGHRES |
| */ |
| if (reprogram && hrtimer_enqueue_reprogram(timer, base)) |
| return; |
| |
| base->first = &timer->node; |
| } |
| |
| rb_link_node(&timer->node, parent, link); |
| rb_insert_color(&timer->node, &base->active); |
| /* |
| * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the |
| * state of a possibly running callback. |
| */ |
| timer->state |= HRTIMER_STATE_ENQUEUED; |
| } |
| |
| /* |
| * __remove_hrtimer - internal function to remove a timer |
| * |
| * Caller must hold the base lock. |
| * |
| * High resolution timer mode reprograms the clock event device when the |
| * timer is the one which expires next. The caller can disable this by setting |
| * reprogram to zero. This is useful, when the context does a reprogramming |
| * anyway (e.g. timer interrupt) |
| */ |
| static void __remove_hrtimer(struct hrtimer *timer, |
| struct hrtimer_clock_base *base, |
| unsigned long newstate, int reprogram) |
| { |
| /* High res. callback list. NOP for !HIGHRES */ |
| if (hrtimer_cb_pending(timer)) |
| hrtimer_remove_cb_pending(timer); |
| else { |
| /* |
| * Remove the timer from the rbtree and replace the |
| * first entry pointer if necessary. |
| */ |
| if (base->first == &timer->node) { |
| base->first = rb_next(&timer->node); |
| /* Reprogram the clock event device. if enabled */ |
| if (reprogram && hrtimer_hres_active()) |
| hrtimer_force_reprogram(base->cpu_base); |
| } |
| rb_erase(&timer->node, &base->active); |
| } |
| timer->state = newstate; |
| } |
| |
| /* |
| * remove hrtimer, called with base lock held |
| */ |
| static inline int |
| remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) |
| { |
| if (hrtimer_is_queued(timer)) { |
| int reprogram; |
| |
| /* |
| * Remove the timer and force reprogramming when high |
| * resolution mode is active and the timer is on the current |
| * CPU. If we remove a timer on another CPU, reprogramming is |
| * skipped. The interrupt event on this CPU is fired and |
| * reprogramming happens in the interrupt handler. This is a |
| * rare case and less expensive than a smp call. |
| */ |
| debug_hrtimer_deactivate(timer); |
| timer_stats_hrtimer_clear_start_info(timer); |
| reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases); |
| __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, |
| reprogram); |
| return 1; |
| } |
| return 0; |
| } |
| |
| /** |
| * hrtimer_start - (re)start an relative timer on the current CPU |
| * @timer: the timer to be added |
| * @tim: expiry time |
| * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) |
| * |
| * Returns: |
| * 0 on success |
| * 1 when the timer was active |
| */ |
| int |
| hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) |
| { |
| struct hrtimer_clock_base *base, *new_base; |
| unsigned long flags; |
| int ret, raise; |
| |
| base = lock_hrtimer_base(timer, &flags); |
| |
| /* Remove an active timer from the queue: */ |
| ret = remove_hrtimer(timer, base); |
| |
| /* Switch the timer base, if necessary: */ |
| new_base = switch_hrtimer_base(timer, base); |
| |
| if (mode == HRTIMER_MODE_REL) { |
| 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 |
| * 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_safe(tim, base->resolution); |
| #endif |
| } |
| |
| timer->expires = tim; |
| |
| timer_stats_hrtimer_set_start_info(timer); |
| |
| /* |
| * Only allow reprogramming if the new base is on this CPU. |
| * (it might still be on another CPU if the timer was pending) |
| */ |
| enqueue_hrtimer(timer, new_base, |
| new_base->cpu_base == &__get_cpu_var(hrtimer_bases)); |
| |
| /* |
| * The timer may be expired and moved to the cb_pending |
| * list. We can not raise the softirq with base lock held due |
| * to a possible deadlock with runqueue lock. |
| */ |
| raise = timer->state == HRTIMER_STATE_PENDING; |
| |
| /* |
| * We use preempt_disable to prevent this task from migrating after |
| * setting up the softirq and raising it. Otherwise, if me migrate |
| * we will raise the softirq on the wrong CPU. |
| */ |
| preempt_disable(); |
| |
| unlock_hrtimer_base(timer, &flags); |
| |
| if (raise) |
| hrtimer_raise_softirq(); |
| preempt_enable(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_start); |
| |
| /** |
| * hrtimer_try_to_cancel - try to deactivate a timer |
| * @timer: hrtimer to stop |
| * |
| * Returns: |
| * 0 when the timer was not active |
| * 1 when the timer was active |
| * -1 when the timer is currently excuting the callback function and |
| * cannot be stopped |
| */ |
| int hrtimer_try_to_cancel(struct hrtimer *timer) |
| { |
| struct hrtimer_clock_base *base; |
| unsigned long flags; |
| int ret = -1; |
| |
| base = lock_hrtimer_base(timer, &flags); |
| |
| if (!hrtimer_callback_running(timer)) |
| ret = remove_hrtimer(timer, base); |
| |
| unlock_hrtimer_base(timer, &flags); |
| |
| return ret; |
| |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel); |
| |
| /** |
| * hrtimer_cancel - cancel a timer and wait for the handler to finish. |
| * @timer: the timer to be cancelled |
| * |
| * Returns: |
| * 0 when the timer was not active |
| * 1 when the timer was active |
| */ |
| int hrtimer_cancel(struct hrtimer *timer) |
| { |
| for (;;) { |
| int ret = hrtimer_try_to_cancel(timer); |
| |
| if (ret >= 0) |
| return ret; |
| cpu_relax(); |
| } |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_cancel); |
| |
| /** |
| * hrtimer_get_remaining - get remaining time for the timer |
| * @timer: the timer to read |
| */ |
| ktime_t hrtimer_get_remaining(const struct hrtimer *timer) |
| { |
| struct hrtimer_clock_base *base; |
| unsigned long flags; |
| ktime_t rem; |
| |
| base = lock_hrtimer_base(timer, &flags); |
| rem = ktime_sub(timer->expires, base->get_time()); |
| unlock_hrtimer_base(timer, &flags); |
| |
| return rem; |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_get_remaining); |
| |
| #ifdef CONFIG_NO_HZ |
| /** |
| * hrtimer_get_next_event - get the time until next expiry event |
| * |
| * Returns the delta to the next expiry event or KTIME_MAX if no timer |
| * is pending. |
| */ |
| ktime_t hrtimer_get_next_event(void) |
| { |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| struct hrtimer_clock_base *base = cpu_base->clock_base; |
| ktime_t delta, mindelta = { .tv64 = KTIME_MAX }; |
| unsigned long flags; |
| int i; |
| |
| spin_lock_irqsave(&cpu_base->lock, flags); |
| |
| if (!hrtimer_hres_active()) { |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { |
| struct hrtimer *timer; |
| |
| if (!base->first) |
| continue; |
| |
| timer = rb_entry(base->first, struct hrtimer, node); |
| delta.tv64 = timer->expires.tv64; |
| delta = ktime_sub(delta, base->get_time()); |
| if (delta.tv64 < mindelta.tv64) |
| mindelta.tv64 = delta.tv64; |
| } |
| } |
| |
| spin_unlock_irqrestore(&cpu_base->lock, flags); |
| |
| if (mindelta.tv64 < 0) |
| mindelta.tv64 = 0; |
| return mindelta; |
| } |
| #endif |
| |
| static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
| enum hrtimer_mode mode) |
| { |
| struct hrtimer_cpu_base *cpu_base; |
| |
| memset(timer, 0, sizeof(struct hrtimer)); |
| |
| cpu_base = &__raw_get_cpu_var(hrtimer_bases); |
| |
| if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS) |
| clock_id = CLOCK_MONOTONIC; |
| |
| timer->base = &cpu_base->clock_base[clock_id]; |
| INIT_LIST_HEAD(&timer->cb_entry); |
| hrtimer_init_timer_hres(timer); |
| |
| #ifdef CONFIG_TIMER_STATS |
| timer->start_site = NULL; |
| timer->start_pid = -1; |
| memset(timer->start_comm, 0, TASK_COMM_LEN); |
| #endif |
| } |
| |
| /** |
| * hrtimer_init - initialize a timer to the given clock |
| * @timer: the timer to be initialized |
| * @clock_id: the clock to be used |
| * @mode: timer mode abs/rel |
| */ |
| void hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
| enum hrtimer_mode mode) |
| { |
| debug_hrtimer_init(timer); |
| __hrtimer_init(timer, clock_id, mode); |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_init); |
| |
| /** |
| * hrtimer_get_res - get the timer resolution for a clock |
| * @which_clock: which clock to query |
| * @tp: pointer to timespec variable to store the resolution |
| * |
| * Store the resolution of the clock selected by @which_clock in the |
| * variable pointed to by @tp. |
| */ |
| int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) |
| { |
| struct hrtimer_cpu_base *cpu_base; |
| |
| cpu_base = &__raw_get_cpu_var(hrtimer_bases); |
| *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_get_res); |
| |
| static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base) |
| { |
| spin_lock_irq(&cpu_base->lock); |
| |
| while (!list_empty(&cpu_base->cb_pending)) { |
| enum hrtimer_restart (*fn)(struct hrtimer *); |
| struct hrtimer *timer; |
| int restart; |
| |
| timer = list_entry(cpu_base->cb_pending.next, |
| struct hrtimer, cb_entry); |
| |
| debug_hrtimer_deactivate(timer); |
| timer_stats_account_hrtimer(timer); |
| |
| fn = timer->function; |
| __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0); |
| spin_unlock_irq(&cpu_base->lock); |
| |
| restart = fn(timer); |
| |
| spin_lock_irq(&cpu_base->lock); |
| |
| timer->state &= ~HRTIMER_STATE_CALLBACK; |
| if (restart == HRTIMER_RESTART) { |
| BUG_ON(hrtimer_active(timer)); |
| /* |
| * Enqueue the timer, allow reprogramming of the event |
| * device |
| */ |
| enqueue_hrtimer(timer, timer->base, 1); |
| } else if (hrtimer_active(timer)) { |
| /* |
| * If the timer was rearmed on another CPU, reprogram |
| * the event device. |
| */ |
| struct hrtimer_clock_base *base = timer->base; |
| |
| if (base->first == &timer->node && |
| hrtimer_reprogram(timer, base)) { |
| /* |
| * Timer is expired. Thus move it from tree to |
| * pending list again. |
| */ |
| __remove_hrtimer(timer, base, |
| HRTIMER_STATE_PENDING, 0); |
| list_add_tail(&timer->cb_entry, |
| &base->cpu_base->cb_pending); |
| } |
| } |
| } |
| spin_unlock_irq(&cpu_base->lock); |
| } |
| |
| static void __run_hrtimer(struct hrtimer *timer) |
| { |
| struct hrtimer_clock_base *base = timer->base; |
| struct hrtimer_cpu_base *cpu_base = base->cpu_base; |
| enum hrtimer_restart (*fn)(struct hrtimer *); |
| int restart; |
| |
| debug_hrtimer_deactivate(timer); |
| __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0); |
| timer_stats_account_hrtimer(timer); |
| |
| fn = timer->function; |
| if (timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ) { |
| /* |
| * Used for scheduler timers, avoid lock inversion with |
| * rq->lock and tasklist_lock. |
| * |
| * These timers are required to deal with enqueue expiry |
| * themselves and are not allowed to migrate. |
| */ |
| spin_unlock(&cpu_base->lock); |
| restart = fn(timer); |
| spin_lock(&cpu_base->lock); |
| } else |
| restart = fn(timer); |
| |
| /* |
| * Note: We clear the CALLBACK bit after enqueue_hrtimer to avoid |
| * reprogramming of the event hardware. This happens at the end of this |
| * function anyway. |
| */ |
| if (restart != HRTIMER_NORESTART) { |
| BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); |
| enqueue_hrtimer(timer, base, 0); |
| } |
| timer->state &= ~HRTIMER_STATE_CALLBACK; |
| } |
| |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| |
| /* |
| * High resolution timer interrupt |
| * Called with interrupts disabled |
| */ |
| void hrtimer_interrupt(struct clock_event_device *dev) |
| { |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| struct hrtimer_clock_base *base; |
| ktime_t expires_next, now; |
| int i, raise = 0; |
| |
| BUG_ON(!cpu_base->hres_active); |
| cpu_base->nr_events++; |
| dev->next_event.tv64 = KTIME_MAX; |
| |
| retry: |
| now = ktime_get(); |
| |
| expires_next.tv64 = KTIME_MAX; |
| |
| base = cpu_base->clock_base; |
| |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { |
| ktime_t basenow; |
| struct rb_node *node; |
| |
| spin_lock(&cpu_base->lock); |
| |
| basenow = ktime_add(now, base->offset); |
| |
| while ((node = base->first)) { |
| struct hrtimer *timer; |
| |
| timer = rb_entry(node, struct hrtimer, node); |
| |
| if (basenow.tv64 < timer->expires.tv64) { |
| ktime_t expires; |
| |
| expires = ktime_sub(timer->expires, |
| base->offset); |
| if (expires.tv64 < expires_next.tv64) |
| expires_next = expires; |
| break; |
| } |
| |
| /* Move softirq callbacks to the pending list */ |
| if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) { |
| __remove_hrtimer(timer, base, |
| HRTIMER_STATE_PENDING, 0); |
| list_add_tail(&timer->cb_entry, |
| &base->cpu_base->cb_pending); |
| raise = 1; |
| continue; |
| } |
| |
| __run_hrtimer(timer); |
| } |
| spin_unlock(&cpu_base->lock); |
| base++; |
| } |
| |
| cpu_base->expires_next = expires_next; |
| |
| /* Reprogramming necessary ? */ |
| if (expires_next.tv64 != KTIME_MAX) { |
| if (tick_program_event(expires_next, 0)) |
| goto retry; |
| } |
| |
| /* Raise softirq ? */ |
| if (raise) |
| raise_softirq(HRTIMER_SOFTIRQ); |
| } |
| |
| static void run_hrtimer_softirq(struct softirq_action *h) |
| { |
| run_hrtimer_pending(&__get_cpu_var(hrtimer_bases)); |
| } |
| |
| #endif /* CONFIG_HIGH_RES_TIMERS */ |
| |
| /* |
| * Called from timer softirq every jiffy, expire hrtimers: |
| * |
| * For HRT its the fall back code to run the softirq in the timer |
| * softirq context in case the hrtimer initialization failed or has |
| * not been done yet. |
| */ |
| void hrtimer_run_pending(void) |
| { |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| |
| if (hrtimer_hres_active()) |
| return; |
| |
| /* |
| * This _is_ ugly: We have to check in the softirq context, |
| * whether we can switch to highres and / or nohz mode. The |
| * clocksource switch happens in the timer interrupt with |
| * xtime_lock held. Notification from there only sets the |
| * check bit in the tick_oneshot code, otherwise we might |
| * deadlock vs. xtime_lock. |
| */ |
| if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) |
| hrtimer_switch_to_hres(); |
| |
| run_hrtimer_pending(cpu_base); |
| } |
| |
| /* |
| * Called from hardirq context every jiffy |
| */ |
| void hrtimer_run_queues(void) |
| { |
| struct rb_node *node; |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| struct hrtimer_clock_base *base; |
| int index, gettime = 1; |
| |
| if (hrtimer_hres_active()) |
| return; |
| |
| for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) { |
| base = &cpu_base->clock_base[index]; |
| |
| if (!base->first) |
| continue; |
| |
| if (base->get_softirq_time) |
| base->softirq_time = base->get_softirq_time(); |
| else if (gettime) { |
| hrtimer_get_softirq_time(cpu_base); |
| gettime = 0; |
| } |
| |
| spin_lock(&cpu_base->lock); |
| |
| while ((node = base->first)) { |
| struct hrtimer *timer; |
| |
| timer = rb_entry(node, struct hrtimer, node); |
| if (base->softirq_time.tv64 <= timer->expires.tv64) |
| break; |
| |
| if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) { |
| __remove_hrtimer(timer, base, |
| HRTIMER_STATE_PENDING, 0); |
| list_add_tail(&timer->cb_entry, |
| &base->cpu_base->cb_pending); |
| continue; |
| } |
| |
| __run_hrtimer(timer); |
| } |
| spin_unlock(&cpu_base->lock); |
| } |
| } |
| |
| /* |
| * Sleep related functions: |
| */ |
| static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer) |
| { |
| struct hrtimer_sleeper *t = |
| container_of(timer, struct hrtimer_sleeper, timer); |
| struct task_struct *task = t->task; |
| |
| t->task = NULL; |
| if (task) |
| wake_up_process(task); |
| |
| return HRTIMER_NORESTART; |
| } |
| |
| void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) |
| { |
| sl->timer.function = hrtimer_wakeup; |
| sl->task = task; |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; |
| #endif |
| } |
| |
| static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode) |
| { |
| hrtimer_init_sleeper(t, current); |
| |
| do { |
| set_current_state(TASK_INTERRUPTIBLE); |
| hrtimer_start(&t->timer, t->timer.expires, mode); |
| if (!hrtimer_active(&t->timer)) |
| t->task = NULL; |
| |
| if (likely(t->task)) |
| schedule(); |
| |
| hrtimer_cancel(&t->timer); |
| mode = HRTIMER_MODE_ABS; |
| |
| } while (t->task && !signal_pending(current)); |
| |
| __set_current_state(TASK_RUNNING); |
| |
| 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 __user *rmtp; |
| int ret = 0; |
| |
| hrtimer_init_on_stack(&t.timer, restart->nanosleep.index, |
| HRTIMER_MODE_ABS); |
| t.timer.expires.tv64 = restart->nanosleep.expires; |
| |
| if (do_nanosleep(&t, HRTIMER_MODE_ABS)) |
| goto out; |
| |
| rmtp = restart->nanosleep.rmtp; |
| if (rmtp) { |
| ret = update_rmtp(&t.timer, rmtp); |
| if (ret <= 0) |
| goto out; |
| } |
| |
| /* The other values in restart are already filled in */ |
| ret = -ERESTART_RESTARTBLOCK; |
| out: |
| destroy_hrtimer_on_stack(&t.timer); |
| return ret; |
| } |
| |
| 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; |
| int ret = 0; |
| |
| hrtimer_init_on_stack(&t.timer, clockid, mode); |
| t.timer.expires = timespec_to_ktime(*rqtp); |
| if (do_nanosleep(&t, mode)) |
| goto out; |
| |
| /* Absolute timers do not update the rmtp value and restart: */ |
| if (mode == HRTIMER_MODE_ABS) { |
| ret = -ERESTARTNOHAND; |
| goto out; |
| } |
| |
| if (rmtp) { |
| ret = update_rmtp(&t.timer, rmtp); |
| if (ret <= 0) |
| goto out; |
| } |
| |
| restart = ¤t_thread_info()->restart_block; |
| restart->fn = hrtimer_nanosleep_restart; |
| restart->nanosleep.index = t.timer.base->index; |
| restart->nanosleep.rmtp = rmtp; |
| restart->nanosleep.expires = t.timer.expires.tv64; |
| |
| ret = -ERESTART_RESTARTBLOCK; |
| out: |
| destroy_hrtimer_on_stack(&t.timer); |
| return ret; |
| } |
| |
| asmlinkage long |
| sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) |
| { |
| struct timespec tu; |
| |
| if (copy_from_user(&tu, rqtp, sizeof(tu))) |
| return -EFAULT; |
| |
| if (!timespec_valid(&tu)) |
| return -EINVAL; |
| |
| return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC); |
| } |
| |
| /* |
| * Functions related to boot-time initialization: |
| */ |
| static void __cpuinit init_hrtimers_cpu(int cpu) |
| { |
| struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu); |
| int i; |
| |
| spin_lock_init(&cpu_base->lock); |
| |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) |
| cpu_base->clock_base[i].cpu_base = cpu_base; |
| |
| INIT_LIST_HEAD(&cpu_base->cb_pending); |
| hrtimer_init_hres(cpu_base); |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| |
| static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, |
| struct hrtimer_clock_base *new_base) |
| { |
| struct hrtimer *timer; |
| struct rb_node *node; |
| |
| while ((node = rb_first(&old_base->active))) { |
| timer = rb_entry(node, struct hrtimer, node); |
| BUG_ON(hrtimer_callback_running(timer)); |
| debug_hrtimer_deactivate(timer); |
| __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0); |
| timer->base = new_base; |
| /* |
| * Enqueue the timer. Allow reprogramming of the event device |
| */ |
| enqueue_hrtimer(timer, new_base, 1); |
| } |
| } |
| |
| static void migrate_hrtimers(int cpu) |
| { |
| struct hrtimer_cpu_base *old_base, *new_base; |
| int i; |
| |
| BUG_ON(cpu_online(cpu)); |
| old_base = &per_cpu(hrtimer_bases, cpu); |
| new_base = &get_cpu_var(hrtimer_bases); |
| |
| tick_cancel_sched_timer(cpu); |
| |
| local_irq_disable(); |
| spin_lock(&new_base->lock); |
| spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); |
| |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { |
| migrate_hrtimer_list(&old_base->clock_base[i], |
| &new_base->clock_base[i]); |
| } |
| |
| spin_unlock(&old_base->lock); |
| spin_unlock(&new_base->lock); |
| local_irq_enable(); |
| put_cpu_var(hrtimer_bases); |
| } |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *hcpu) |
| { |
| unsigned int cpu = (long)hcpu; |
| |
| switch (action) { |
| |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| init_hrtimers_cpu(cpu); |
| break; |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &cpu); |
| migrate_hrtimers(cpu); |
| break; |
| #endif |
| |
| default: |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block __cpuinitdata hrtimers_nb = { |
| .notifier_call = hrtimer_cpu_notify, |
| }; |
| |
| void __init hrtimers_init(void) |
| { |
| hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| register_cpu_notifier(&hrtimers_nb); |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq); |
| #endif |
| } |
| |