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-rw-r--r--arch/ia64/kernel/time.c456
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diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
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+/*
+ * linux/arch/ia64/kernel/time.c
+ *
+ * Copyright (C) 1998-2003 Hewlett-Packard Co
+ * Stephane Eranian <eranian@hpl.hp.com>
+ * David Mosberger <davidm@hpl.hp.com>
+ * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
+ * Copyright (C) 1999-2000 VA Linux Systems
+ * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
+ */
+
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/efi.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 "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;
+
+volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
+
+#ifdef CONFIG_IA64_DEBUG_IRQ
+
+unsigned long last_cli_ip;
+EXPORT_SYMBOL(last_cli_ip);
+
+#endif
+
+#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)
+{
+ unsigned long new_itm;
+
+ if (cpu_is_offline(smp_processor_id())) {
+ return IRQ_HANDLED;
+ }
+
+ platform_timer_interrupt(irq, dev_id);
+
+ new_itm = local_cpu_data->itm_next;
+
+ if (!time_after(ia64_get_itc(), new_itm))
+ printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
+ ia64_get_itc(), new_itm);
+
+ profile_tick(CPU_PROFILING);
+
+ if (paravirt_do_steal_accounting(&new_itm))
+ goto skip_process_time_accounting;
+
+ while (1) {
+ update_process_times(user_mode(get_irq_regs()));
+
+ new_itm += local_cpu_data->itm_delta;
+
+ 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
+ * xtime_update() which in turn would let our clock run
+ * too fast (with the potentially devastating effect
+ * of losing monotony of time).
+ */
+ while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
+ new_itm += local_cpu_data->itm_delta;
+ ia64_set_itm(new_itm);
+ /* double check, in case we got hit by a (slow) PMI: */
+ } while (time_after_eq(ia64_get_itc(), new_itm));
+ return IRQ_HANDLED;
+}
+
+/*
+ * Encapsulate access to the itm structure for SMP.
+ */
+void
+ia64_cpu_local_tick (void)
+{
+ int cpu = smp_processor_id();
+ unsigned long shift = 0, delta;
+
+ /* arrange for the cycle counter to generate a timer interrupt: */
+ ia64_set_itv(IA64_TIMER_VECTOR);
+
+ delta = local_cpu_data->itm_delta;
+ /*
+ * Stagger the timer tick for each CPU so they don't occur all at (almost) the
+ * same time:
+ */
+ if (cpu) {
+ unsigned long hi = 1UL << ia64_fls(cpu);
+ shift = (2*(cpu - hi) + 1) * delta/hi/2;
+ }
+ local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
+ ia64_set_itm(local_cpu_data->itm_next);
+}
+
+static int nojitter;
+
+static int __init nojitter_setup(char *str)
+{
+ nojitter = 1;
+ printk("Jitter checking for ITC timers disabled\n");
+ return 1;
+}
+
+__setup("nojitter", nojitter_setup);
+
+
+void ia64_init_itm(void)
+{
+ unsigned long platform_base_freq, itc_freq;
+ struct pal_freq_ratio itc_ratio, proc_ratio;
+ long status, platform_base_drift, itc_drift;
+
+ /*
+ * According to SAL v2.6, we need to use a SAL call to determine the platform base
+ * frequency and then a PAL call to determine the frequency ratio between the ITC
+ * and the base frequency.
+ */
+ status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
+ &platform_base_freq, &platform_base_drift);
+ if (status != 0) {
+ printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
+ } else {
+ status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
+ if (status != 0)
+ printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
+ }
+ if (status != 0) {
+ /* invent "random" values */
+ printk(KERN_ERR
+ "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
+ platform_base_freq = 100000000;
+ platform_base_drift = -1; /* no drift info */
+ itc_ratio.num = 3;
+ itc_ratio.den = 1;
+ }
+ if (platform_base_freq < 40000000) {
+ printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
+ platform_base_freq);
+ platform_base_freq = 75000000;
+ platform_base_drift = -1;
+ }
+ if (!proc_ratio.den)
+ proc_ratio.den = 1; /* avoid division by zero */
+ if (!itc_ratio.den)
+ itc_ratio.den = 1; /* avoid division by zero */
+
+ 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=%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);
+
+ if (platform_base_drift != -1) {
+ itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
+ printk("+/-%ldppm\n", itc_drift);
+ } else {
+ itc_drift = -1;
+ printk("\n");
+ }
+
+ local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
+ local_cpu_data->itc_freq = itc_freq;
+ local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
+ local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
+ + itc_freq/2)/itc_freq;
+
+ if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
+#ifdef CONFIG_SMP
+ /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
+ * Jitter compensation requires a cmpxchg which may limit
+ * the scalability of the syscalls for retrieving time.
+ * The ITC synchronization is usually successful to within a few
+ * ITC ticks but this is not a sure thing. If you need to improve
+ * timer performance in SMP situations then boot the kernel with the
+ * "nojitter" option. However, doing so may result in time fluctuating (maybe
+ * even going backward) if the ITC offsets between the individual CPUs
+ * are too large.
+ */
+ if (!nojitter)
+ itc_jitter_data.itc_jitter = 1;
+#endif
+ } 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 = IRQF_IRQPOLL,
+ .name = "timer"
+};
+
+void read_persistent_clock(struct timespec *ts)
+{
+ efi_gettimeofday(ts);
+}
+
+void __init
+time_init (void)
+{
+ register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
+ ia64_init_itm();
+}
+
+/*
+ * 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, cycle_t cycle_last)
+{
+ 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 = 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);
+}
+