diff options
Diffstat (limited to 'arch/ia64/kernel/time.c')
| -rw-r--r-- | arch/ia64/kernel/time.c | 306 |
1 files changed, 263 insertions, 43 deletions
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 5b7e736f3b4..71c52bc7c28 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -8,7 +8,6 @@ * Copyright (C) 1999-2000 VA Linux Systems * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com> */ -#include <linux/config.h> #include <linux/cpu.h> #include <linux/init.h> @@ -19,20 +18,27 @@ #include <linux/time.h> #include <linux/interrupt.h> #include <linux/efi.h> -#include <linux/profile.h> #include <linux/timex.h> +#include <linux/timekeeper_internal.h> +#include <linux/platform_device.h> #include <asm/machvec.h> #include <asm/delay.h> #include <asm/hw_irq.h> +#include <asm/paravirt.h> #include <asm/ptrace.h> #include <asm/sal.h> #include <asm/sections.h> -#include <asm/system.h> -extern unsigned long wall_jiffies; +#include "fsyscall_gtod_data.h" + +static cycle_t itc_get_cycles(struct clocksource *cs); + +struct fsyscall_gtod_data_t fsyscall_gtod_data; + +struct itc_jitter_data_t itc_jitter_data; -#define TIME_KEEPER_ID 0 /* smp_processor_id() of time-keeper */ +volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */ #ifdef CONFIG_IA64_DEBUG_IRQ @@ -41,22 +47,114 @@ EXPORT_SYMBOL(last_cli_ip); #endif -static struct time_interpolator itc_interpolator = { - .shift = 16, - .mask = 0xffffffffffffffffLL, - .source = TIME_SOURCE_CPU +#ifdef CONFIG_PARAVIRT +/* We need to define a real function for sched_clock, to override the + weak default version */ +unsigned long long sched_clock(void) +{ + return paravirt_sched_clock(); +} +#endif + +#ifdef CONFIG_PARAVIRT +static void +paravirt_clocksource_resume(struct clocksource *cs) +{ + if (pv_time_ops.clocksource_resume) + pv_time_ops.clocksource_resume(); +} +#endif + +static struct clocksource clocksource_itc = { + .name = "itc", + .rating = 350, + .read = itc_get_cycles, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +#ifdef CONFIG_PARAVIRT + .resume = paravirt_clocksource_resume, +#endif }; +static struct clocksource *itc_clocksource; + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + +#include <linux/kernel_stat.h> + +extern cputime_t cycle_to_cputime(u64 cyc); + +void vtime_account_user(struct task_struct *tsk) +{ + cputime_t delta_utime; + struct thread_info *ti = task_thread_info(tsk); + + if (ti->ac_utime) { + delta_utime = cycle_to_cputime(ti->ac_utime); + account_user_time(tsk, delta_utime, delta_utime); + ti->ac_utime = 0; + } +} + +/* + * Called from the context switch with interrupts disabled, to charge all + * accumulated times to the current process, and to prepare accounting on + * the next process. + */ +void arch_vtime_task_switch(struct task_struct *prev) +{ + struct thread_info *pi = task_thread_info(prev); + struct thread_info *ni = task_thread_info(current); + + pi->ac_stamp = ni->ac_stamp; + ni->ac_stime = ni->ac_utime = 0; +} + +/* + * Account time for a transition between system, hard irq or soft irq state. + * Note that this function is called with interrupts enabled. + */ +static cputime_t vtime_delta(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + cputime_t delta_stime; + __u64 now; + + WARN_ON_ONCE(!irqs_disabled()); + + now = ia64_get_itc(); + + delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp)); + ti->ac_stime = 0; + ti->ac_stamp = now; + + return delta_stime; +} + +void vtime_account_system(struct task_struct *tsk) +{ + cputime_t delta = vtime_delta(tsk); + + account_system_time(tsk, 0, delta, delta); +} +EXPORT_SYMBOL_GPL(vtime_account_system); + +void vtime_account_idle(struct task_struct *tsk) +{ + account_idle_time(vtime_delta(tsk)); +} + +#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ static irqreturn_t -timer_interrupt (int irq, void *dev_id, struct pt_regs *regs) +timer_interrupt (int irq, void *dev_id) { unsigned long new_itm; - if (unlikely(cpu_is_offline(smp_processor_id()))) { + if (cpu_is_offline(smp_processor_id())) { return IRQ_HANDLED; } - platform_timer_interrupt(irq, dev_id, regs); + platform_timer_interrupt(irq, dev_id); new_itm = local_cpu_data->itm_next; @@ -64,38 +162,40 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs) printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n", ia64_get_itc(), new_itm); - profile_tick(CPU_PROFILING, regs); + profile_tick(CPU_PROFILING); + + if (paravirt_do_steal_accounting(&new_itm)) + goto skip_process_time_accounting; while (1) { - update_process_times(user_mode(regs)); + update_process_times(user_mode(get_irq_regs())); new_itm += local_cpu_data->itm_delta; - if (smp_processor_id() == TIME_KEEPER_ID) { - /* - * Here we are in the timer irq handler. We have irqs locally - * disabled, but we don't know if the timer_bh is running on - * another CPU. We need to avoid to SMP race by acquiring the - * xtime_lock. - */ - write_seqlock(&xtime_lock); - do_timer(regs); - local_cpu_data->itm_next = new_itm; - write_sequnlock(&xtime_lock); - } else - local_cpu_data->itm_next = new_itm; + if (smp_processor_id() == time_keeper_id) + xtime_update(1); + + local_cpu_data->itm_next = new_itm; if (time_after(new_itm, ia64_get_itc())) break; + + /* + * Allow IPIs to interrupt the timer loop. + */ + local_irq_enable(); + local_irq_disable(); } +skip_process_time_accounting: + do { /* * If we're too close to the next clock tick for * comfort, we increase the safety margin by * intentionally dropping the next tick(s). We do NOT * update itm.next because that would force us to call - * do_timer() which in turn would let our clock run + * xtime_update() which in turn would let our clock run * too fast (with the potentially devastating effect * of losing monotony of time). */ @@ -144,8 +244,7 @@ static int __init nojitter_setup(char *str) __setup("nojitter", nojitter_setup); -void __devinit -ia64_init_itm (void) +void ia64_init_itm(void) { unsigned long platform_base_freq, itc_freq; struct pal_freq_ratio itc_ratio, proc_ratio; @@ -188,7 +287,7 @@ ia64_init_itm (void) itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den; local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ; - printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%lu/%lu, " + printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, " "ITC freq=%lu.%03luMHz", smp_processor_id(), platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000, itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000); @@ -208,8 +307,6 @@ ia64_init_itm (void) + itc_freq/2)/itc_freq; if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { - itc_interpolator.frequency = local_cpu_data->itc_freq; - itc_interpolator.drift = itc_drift; #ifdef CONFIG_SMP /* On IA64 in an SMP configuration ITCs are never accurately synchronized. * Jitter compensation requires a cmpxchg which may limit @@ -221,31 +318,154 @@ ia64_init_itm (void) * even going backward) if the ITC offsets between the individual CPUs * are too large. */ - if (!nojitter) itc_interpolator.jitter = 1; + if (!nojitter) + itc_jitter_data.itc_jitter = 1; #endif - register_time_interpolator(&itc_interpolator); - } + } else + /* + * ITC is drifty and we have not synchronized the ITCs in smpboot.c. + * ITC values may fluctuate significantly between processors. + * Clock should not be used for hrtimers. Mark itc as only + * useful for boot and testing. + * + * Note that jitter compensation is off! There is no point of + * synchronizing ITCs since they may be large differentials + * that change over time. + * + * The only way to fix this would be to repeatedly sync the + * ITCs. Until that time we have to avoid ITC. + */ + clocksource_itc.rating = 50; + + paravirt_init_missing_ticks_accounting(smp_processor_id()); + + /* avoid softlock up message when cpu is unplug and plugged again. */ + touch_softlockup_watchdog(); /* Setup the CPU local timer tick */ ia64_cpu_local_tick(); + + if (!itc_clocksource) { + clocksource_register_hz(&clocksource_itc, + local_cpu_data->itc_freq); + itc_clocksource = &clocksource_itc; + } +} + +static cycle_t itc_get_cycles(struct clocksource *cs) +{ + unsigned long lcycle, now, ret; + + if (!itc_jitter_data.itc_jitter) + return get_cycles(); + + lcycle = itc_jitter_data.itc_lastcycle; + now = get_cycles(); + if (lcycle && time_after(lcycle, now)) + return lcycle; + + /* + * Keep track of the last timer value returned. + * In an SMP environment, you could lose out in contention of + * cmpxchg. If so, your cmpxchg returns new value which the + * winner of contention updated to. Use the new value instead. + */ + ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now); + if (unlikely(ret != lcycle)) + return ret; + + return now; } + static struct irqaction timer_irqaction = { .handler = timer_interrupt, - .flags = SA_INTERRUPT, + .flags = IRQF_IRQPOLL, .name = "timer" }; +static struct platform_device rtc_efi_dev = { + .name = "rtc-efi", + .id = -1, +}; + +static int __init rtc_init(void) +{ + if (platform_device_register(&rtc_efi_dev) < 0) + printk(KERN_ERR "unable to register rtc device...\n"); + + /* not necessarily an error */ + return 0; +} +module_init(rtc_init); + +void read_persistent_clock(struct timespec *ts) +{ + efi_gettimeofday(ts); +} + void __init time_init (void) { register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction); - efi_gettimeofday(&xtime); ia64_init_itm(); +} - /* - * Initialize wall_to_monotonic such that adding it to xtime will yield zero, the - * tv_nsec field must be normalized (i.e., 0 <= nsec < NSEC_PER_SEC). - */ - set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); +/* + * Generic udelay assumes that if preemption is allowed and the thread + * migrates to another CPU, that the ITC values are synchronized across + * all CPUs. + */ +static void +ia64_itc_udelay (unsigned long usecs) +{ + unsigned long start = ia64_get_itc(); + unsigned long end = start + usecs*local_cpu_data->cyc_per_usec; + + while (time_before(ia64_get_itc(), end)) + cpu_relax(); +} + +void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay; + +void +udelay (unsigned long usecs) +{ + (*ia64_udelay)(usecs); +} +EXPORT_SYMBOL(udelay); + +/* IA64 doesn't cache the timezone */ +void update_vsyscall_tz(void) +{ } + +void update_vsyscall_old(struct timespec *wall, struct timespec *wtm, + struct clocksource *c, u32 mult) +{ + write_seqcount_begin(&fsyscall_gtod_data.seq); + + /* copy fsyscall clock data */ + fsyscall_gtod_data.clk_mask = c->mask; + fsyscall_gtod_data.clk_mult = mult; + fsyscall_gtod_data.clk_shift = c->shift; + fsyscall_gtod_data.clk_fsys_mmio = c->archdata.fsys_mmio; + fsyscall_gtod_data.clk_cycle_last = c->cycle_last; + + /* copy kernel time structures */ + fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec; + fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec; + fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec + + wall->tv_sec; + fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec + + wall->tv_nsec; + + /* normalize */ + while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) { + fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC; + fsyscall_gtod_data.monotonic_time.tv_sec++; + } + + write_seqcount_end(&fsyscall_gtod_data.seq); +} + |