diff options
Diffstat (limited to 'kernel/time/hrtimer.c')
| -rw-r--r-- | kernel/time/hrtimer.c | 1915 |
1 files changed, 1915 insertions, 0 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c new file mode 100644 index 000000000000..3ab28993f6e0 --- /dev/null +++ b/kernel/time/hrtimer.c @@ -0,0 +1,1915 @@ +/* + * 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/export.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 <linux/sched.h> +#include <linux/sched/sysctl.h> +#include <linux/sched/rt.h> +#include <linux/sched/deadline.h> +#include <linux/timer.h> +#include <linux/freezer.h> + +#include <asm/uaccess.h> + +#include <trace/events/timer.h> + +/* + * The timer bases: + * + * There are more clockids then hrtimer bases. Thus, we index + * into the timer bases by the hrtimer_base_type enum. When trying + * to reach a base using a clockid, hrtimer_clockid_to_base() + * is used to convert from clockid to the proper hrtimer_base_type. + */ +DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = +{ + + .lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock), + .clock_base = + { + { + .index = HRTIMER_BASE_MONOTONIC, + .clockid = CLOCK_MONOTONIC, + .get_time = &ktime_get, + .resolution = KTIME_LOW_RES, + }, + { + .index = HRTIMER_BASE_REALTIME, + .clockid = CLOCK_REALTIME, + .get_time = &ktime_get_real, + .resolution = KTIME_LOW_RES, + }, + { + .index = HRTIMER_BASE_BOOTTIME, + .clockid = CLOCK_BOOTTIME, + .get_time = &ktime_get_boottime, + .resolution = KTIME_LOW_RES, + }, + { + .index = HRTIMER_BASE_TAI, + .clockid = CLOCK_TAI, + .get_time = &ktime_get_clocktai, + .resolution = KTIME_LOW_RES, + }, + } +}; + +static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = { + [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME, + [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC, + [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME, + [CLOCK_TAI] = HRTIMER_BASE_TAI, +}; + +static inline int hrtimer_clockid_to_base(clockid_t clock_id) +{ + return hrtimer_clock_to_base_table[clock_id]; +} + + +/* + * 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, mono, boot; + struct timespec xts, tom, slp; + s32 tai_offset; + + get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp); + tai_offset = timekeeping_get_tai_offset(); + + xtim = timespec_to_ktime(xts); + mono = ktime_add(xtim, timespec_to_ktime(tom)); + boot = ktime_add(mono, timespec_to_ktime(slp)); + base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim; + base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono; + base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot; + base->clock_base[HRTIMER_BASE_TAI].softirq_time = + ktime_add(xtim, ktime_set(tai_offset, 0)); +} + +/* + * 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)) { + raw_spin_lock_irqsave(&base->cpu_base->lock, *flags); + if (likely(base == timer->base)) + return base; + /* The timer has migrated to another CPU: */ + raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags); + } + cpu_relax(); + } +} + +/* + * With HIGHRES=y we do not migrate the timer when it is expiring + * before the next event on the target cpu because we cannot reprogram + * the target cpu hardware and we would cause it to fire late. + * + * Called with cpu_base->lock of target cpu held. + */ +static int +hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base) +{ +#ifdef CONFIG_HIGH_RES_TIMERS + ktime_t expires; + + if (!new_base->cpu_base->hres_active) + return 0; + + expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset); + return expires.tv64 <= new_base->cpu_base->expires_next.tv64; +#else + return 0; +#endif +} + +/* + * 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, + int pinned) +{ + struct hrtimer_clock_base *new_base; + struct hrtimer_cpu_base *new_cpu_base; + int this_cpu = smp_processor_id(); + int cpu = get_nohz_timer_target(pinned); + int basenum = base->index; + +again: + new_cpu_base = &per_cpu(hrtimer_bases, cpu); + new_base = &new_cpu_base->clock_base[basenum]; + + if (base != new_base) { + /* + * We are trying to move timer to new_base. + * 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; + raw_spin_unlock(&base->cpu_base->lock); + raw_spin_lock(&new_base->cpu_base->lock); + + if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) { + cpu = this_cpu; + raw_spin_unlock(&new_base->cpu_base->lock); + raw_spin_lock(&base->cpu_base->lock); + timer->base = base; + goto again; + } + timer->base = new_base; + } else { + if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) { + cpu = this_cpu; + goto again; + } + } + 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; + + raw_spin_lock_irqsave(&base->cpu_base->lock, *flags); + + return base; +} + +# define switch_hrtimer_base(t, b, p) (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); + + /* Make sure nsec fits into long */ + if (unlikely(nsec > KTIME_SEC_MAX)) + return (ktime_t){ .tv64 = KTIME_MAX }; + + 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; + int sft = 0; + + dclc = ktime_to_ns(kt); + /* 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; +} + +EXPORT_SYMBOL_GPL(ktime_add_safe); + +#ifdef CONFIG_DEBUG_OBJECTS_TIMERS + +static struct debug_obj_descr hrtimer_debug_descr; + +static void *hrtimer_debug_hint(void *addr) +{ + return ((struct hrtimer *) addr)->function; +} + +/* + * 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", + .debug_hint = hrtimer_debug_hint, + .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); +} +EXPORT_SYMBOL_GPL(hrtimer_init_on_stack); + +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 + +static inline void +debug_init(struct hrtimer *timer, clockid_t clockid, + enum hrtimer_mode mode) +{ + debug_hrtimer_init(timer); + trace_hrtimer_init(timer, clockid, mode); +} + +static inline void debug_activate(struct hrtimer *timer) +{ + debug_hrtimer_activate(timer); + trace_hrtimer_start(timer); +} + +static inline void debug_deactivate(struct hrtimer *timer) +{ + debug_hrtimer_deactivate(timer); + trace_hrtimer_cancel(timer); +} + +/* 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 __this_cpu_read(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 skip_equal) +{ + int i; + struct hrtimer_clock_base *base = cpu_base->clock_base; + ktime_t expires, expires_next; + + expires_next.tv64 = KTIME_MAX; + + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { + struct hrtimer *timer; + struct timerqueue_node *next; + + next = timerqueue_getnext(&base->active); + if (!next) + continue; + timer = container_of(next, struct hrtimer, node); + + expires = ktime_sub(hrtimer_get_expires(timer), base->offset); + /* + * clock_was_set() has changed base->offset so the + * result might be negative. Fix it up to prevent a + * false positive in clockevents_program_event() + */ + if (expires.tv64 < 0) + expires.tv64 = 0; + if (expires.tv64 < expires_next.tv64) + expires_next = expires; + } + + if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64) + return; + + cpu_base->expires_next.tv64 = expires_next.tv64; + + /* + * If a hang was detected in the last timer interrupt then we + * leave the hang delay active in the hardware. We want the + * system to make progress. That also prevents the following + * scenario: + * T1 expires 50ms from now + * T2 expires 5s from now + * + * T1 is removed, so this code is called and would reprogram + * the hardware to 5s from now. Any hrtimer_start after that + * will not reprogram the hardware due to hang_detected being + * set. So we'd effectivly block all timers until the T2 event + * fires. + */ + if (cpu_base->hang_detected) + return; + + 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) +{ + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset); + int res; + + WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 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 >= cpu_base->expires_next.tv64) + return 0; + + /* + * If a hang was detected in the last timer interrupt then we + * do not schedule a timer which is earlier than the expiry + * which we enforced in the hang detection. We want the system + * to make progress. + */ + if (cpu_base->hang_detected) + return 0; + + /* + * Clockevents returns -ETIME, when the event was in the past. + */ + res = tick_program_event(expires, 0); + if (!IS_ERR_VALUE(res)) + cpu_base->expires_next = expires; + return res; +} + +/* + * 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; +} + +/* + * 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) +{ + return base->cpu_base->hres_active && hrtimer_reprogram(timer, base); +} + +static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base) +{ + ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset; + ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset; + ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset; + + return ktime_get_update_offsets(offs_real, offs_boot, offs_tai); +} + +/* + * 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 = &__get_cpu_var(hrtimer_bases); + + if (!hrtimer_hres_active()) + return; + + raw_spin_lock(&base->lock); + hrtimer_update_base(base); + hrtimer_force_reprogram(base, 0); + raw_spin_unlock(&base->lock); +} + +/* + * Switch to high resolution mode + */ +static int hrtimer_switch_to_hres(void) +{ + int i, 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; + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) + base->clock_base[i].resolution = KTIME_HIGH_RES; + + tick_setup_sched_timer(); + /* "Retrigger" the interrupt to get things going */ + retrigger_next_event(NULL); + local_irq_restore(flags); + return 1; +} + +static void clock_was_set_work(struct work_struct *work) +{ + clock_was_set(); +} + +static DECLARE_WORK(hrtimer_work, clock_was_set_work); + +/* + * Called from timekeeping and resume code to reprogramm the hrtimer + * interrupt device on all cpus. + */ +void clock_was_set_delayed(void) +{ + schedule_work(&hrtimer_work); +} + +#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, int skip_equal) { } +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 retrigger_next_event(void *arg) { } + +#endif /* CONFIG_HIGH_RES_TIMERS */ + +/* + * 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) +{ +#ifdef CONFIG_HIGH_RES_TIMERS + /* Retrigger the CPU local events everywhere */ + on_each_cpu(retrigger_next_event, NULL, 1); +#endif + timerfd_clock_was_set(); +} + +/* + * During resume we might have to reprogram the high resolution timer + * interrupt on all online CPUs. However, all other CPUs will be + * stopped with IRQs interrupts disabled so the clock_was_set() call + * must be deferred. + */ +void hrtimers_resume(void) +{ + WARN_ONCE(!irqs_disabled(), + KERN_INFO "hrtimers_resume() called with IRQs enabled!"); + + /* Retrigger on the local CPU */ + retrigger_next_event(NULL); + /* And schedule a retrigger for all others */ + clock_was_set_delayed(); +} + +static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) +{ +#ifdef CONFIG_TIMER_STATS + if (timer->start_site) + return; + timer->start_site = __builtin_return_address(0); + memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); + timer->start_pid = current->pid; +#endif +} + +static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) +{ +#ifdef CONFIG_TIMER_STATS + timer->start_site = NULL; +#endif +} + +static inline void timer_stats_account_hrtimer(struct hrtimer *timer) +{ +#ifdef CONFIG_TIMER_STATS + if (likely(!timer_stats_active)) + return; + timer_stats_update_stats(timer, timer->start_pid, timer->start_site, + timer->function, timer->start_comm, 0); +#endif +} + +/* + * Counterpart to lock_hrtimer_base above: + */ +static inline +void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) +{ + raw_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, hrtimer_get_expires(timer)); + + 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); + hrtimer_add_expires_ns(timer, incr * orun); + if (hrtimer_get_expires_tv64(timer) > now.tv64) + return orun; + /* + * This (and the ktime_add() below) is the + * correction for exact: + */ + orun++; + } + hrtimer_add_expires(timer, 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. + * + * Returns 1 when the new timer is the leftmost timer in the tree. + */ +static int enqueue_hrtimer(struct hrtimer *timer, + struct hrtimer_clock_base *base) +{ + debug_activate(timer); + + timerqueue_add(&base->active, &timer->node); + base->cpu_base->active_bases |= 1 << base->index; + + /* + * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the + * state of a possibly running callback. + */ + timer->state |= HRTIMER_STATE_ENQUEUED; + + return (&timer->node == base->active.next); +} + +/* + * __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) +{ + struct timerqueue_node *next_timer; + if (!(timer->state & HRTIMER_STATE_ENQUEUED)) + goto out; + + next_timer = timerqueue_getnext(&base->active); + timerqueue_del(&base->active, &timer->node); + if (&timer->node == next_timer) { +#ifdef CONFIG_HIGH_RES_TIMERS + /* Reprogram the clock event device. if enabled */ + if (reprogram && hrtimer_hres_active()) { + ktime_t expires; + + expires = ktime_sub(hrtimer_get_expires(timer), + base->offset); + if (base->cpu_base->expires_next.tv64 == expires.tv64) + hrtimer_force_reprogram(base->cpu_base, 1); + } +#endif + } + if (!timerqueue_getnext(&base->active)) + base->cpu_base->active_bases &= ~(1 << base->index); +out: + 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)) { + unsigned long state; + 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_deactivate(timer); + timer_stats_hrtimer_clear_start_info(timer); + reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases); + /* + * We must preserve the CALLBACK state flag here, + * otherwise we could move the timer base in + * switch_hrtimer_base. + */ + state = timer->state & HRTIMER_STATE_CALLBACK; + __remove_hrtimer(timer, base, state, reprogram); + return 1; + } + return 0; +} + +int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, + unsigned long delta_ns, const enum hrtimer_mode mode, + int wakeup) +{ + struct hrtimer_clock_base *base, *new_base; + unsigned long flags; + int ret, leftmost; + + base = lock_hrtimer_base(timer, &flags); + + /* Remove an active timer from the queue: */ + ret = remove_hrtimer(timer, base); + + if (mode & HRTIMER_MODE_REL) { + tim = ktime_add_safe(tim, 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 + } + + hrtimer_set_expires_range_ns(timer, tim, delta_ns); + + /* Switch the timer base, if necessary: */ + new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED); + + timer_stats_hrtimer_set_start_info(timer); + + leftmost = enqueue_hrtimer(timer, new_base); + + /* + * Only allow reprogramming if the new base is on this CPU. + * (it might still be on another CPU if the timer was pending) + * + * XXX send_remote_softirq() ? + */ + if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases) + && hrtimer_enqueue_reprogram(timer, new_base)) { + if (wakeup) { + /* + * We need to drop cpu_base->lock to avoid a + * lock ordering issue vs. rq->lock. + */ + raw_spin_unlock(&new_base->cpu_base->lock); + raise_softirq_irqoff(HRTIMER_SOFTIRQ); + local_irq_restore(flags); + return ret; + } else { + __raise_softirq_irqoff(HRTIMER_SOFTIRQ); + } + } + + unlock_hrtimer_base(timer, &flags); + + return ret; +} +EXPORT_SYMBOL_GPL(__hrtimer_start_range_ns); + +/** + * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU + * @timer: the timer to be added + * @tim: expiry time + * @delta_ns: "slack" range for the timer + * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or + * relative (HRTIMER_MODE_REL) + * + * Returns: + * 0 on success + * 1 when the timer was active + */ +int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, + unsigned long delta_ns, const enum hrtimer_mode mode) +{ + return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1); +} +EXPORT_SYMBOL_GPL(hrtimer_start_range_ns); + +/** + * hrtimer_start - (re)start an hrtimer on the current CPU + * @timer: the timer to be added + * @tim: expiry time + * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or + * relative (HRTIMER_MODE_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) +{ + return __hrtimer_start_range_ns(timer, tim, 0, mode, 1); +} +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) +{ + unsigned long flags; + ktime_t rem; + + lock_hrtimer_base(timer, &flags); + rem = hrtimer_expires_remaining(timer); + unlock_hrtimer_base(timer, &flags); + + return rem; +} +EXPORT_SYMBOL_GPL(hrtimer_get_remaining); + +#ifdef CONFIG_NO_HZ_COMMON +/** + * 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; + + raw_spin_lock_irqsave(&cpu_base->lock, flags); + + if (!hrtimer_hres_active()) { + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { + struct hrtimer *timer; + struct timerqueue_node *next; + + next = timerqueue_getnext(&base->active); + if (!next) + continue; + + timer = container_of(next, struct hrtimer, node); + delta.tv64 = hrtimer_get_expires_tv64(timer); + delta = ktime_sub(delta, base->get_time()); + if (delta.tv64 < mindelta.tv64) + mindelta.tv64 = delta.tv64; + } + } + + raw_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; + int 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; + + base = hrtimer_clockid_to_base(clock_id); + timer->base = &cpu_base->clock_base[base]; + timerqueue_init(&timer->node); + +#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: th |