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Diffstat (limited to 'arch/ia64/kernel/time.c')
-rw-r--r-- | arch/ia64/kernel/time.c | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c new file mode 100644 index 0000000000..83ef044b63 --- /dev/null +++ b/arch/ia64/kernel/time.c @@ -0,0 +1,463 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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/nmi.h> +#include <linux/interrupt.h> +#include <linux/efi.h> +#include <linux/timex.h> +#include <linux/timekeeper_internal.h> +#include <linux/platform_device.h> +#include <linux/sched/cputime.h> + +#include <asm/cputime.h> +#include <asm/delay.h> +#include <asm/efi.h> +#include <asm/hw_irq.h> +#include <asm/ptrace.h> +#include <asm/sal.h> +#include <asm/sections.h> + +#include "fsyscall_gtod_data.h" +#include "irq.h" + +static u64 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 + +static struct clocksource clocksource_itc = { + .name = "itc", + .rating = 350, + .read = itc_get_cycles, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; +static struct clocksource *itc_clocksource; + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + +#include <linux/kernel_stat.h> + +extern u64 cycle_to_nsec(u64 cyc); + +void vtime_flush(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + u64 delta; + + if (ti->utime) + account_user_time(tsk, cycle_to_nsec(ti->utime)); + + if (ti->gtime) + account_guest_time(tsk, cycle_to_nsec(ti->gtime)); + + if (ti->idle_time) + account_idle_time(cycle_to_nsec(ti->idle_time)); + + if (ti->stime) { + delta = cycle_to_nsec(ti->stime); + account_system_index_time(tsk, delta, CPUTIME_SYSTEM); + } + + if (ti->hardirq_time) { + delta = cycle_to_nsec(ti->hardirq_time); + account_system_index_time(tsk, delta, CPUTIME_IRQ); + } + + if (ti->softirq_time) { + delta = cycle_to_nsec(ti->softirq_time); + account_system_index_time(tsk, delta, CPUTIME_SOFTIRQ); + } + + ti->utime = 0; + ti->gtime = 0; + ti->idle_time = 0; + ti->stime = 0; + ti->hardirq_time = 0; + ti->softirq_time = 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); + + ni->ac_stamp = pi->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 __u64 vtime_delta(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + __u64 now, delta_stime; + + WARN_ON_ONCE(!irqs_disabled()); + + now = ia64_get_itc(); + delta_stime = now - ti->ac_stamp; + ti->ac_stamp = now; + + return delta_stime; +} + +void vtime_account_kernel(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + __u64 stime = vtime_delta(tsk); + + if (tsk->flags & PF_VCPU) + ti->gtime += stime; + else + ti->stime += stime; +} +EXPORT_SYMBOL_GPL(vtime_account_kernel); + +void vtime_account_idle(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + + ti->idle_time += vtime_delta(tsk); +} + +void vtime_account_softirq(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + + ti->softirq_time += vtime_delta(tsk); +} + +void vtime_account_hardirq(struct task_struct *tsk) +{ + struct thread_info *ti = task_thread_info(tsk); + + ti->hardirq_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; + } + + 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); + + while (1) { + new_itm += local_cpu_data->itm_delta; + + legacy_timer_tick(smp_processor_id() == time_keeper_id); + + 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(); + } + + 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; + + /* 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 u64 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; +} + +void read_persistent_clock64(struct timespec64 *ts) +{ + efi_gettimeofday(ts); +} + +void __init +time_init (void) +{ + register_percpu_irq(IA64_TIMER_VECTOR, timer_interrupt, IRQF_IRQPOLL, + "timer"); + 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(struct timekeeper *tk) +{ + write_seqcount_begin(&fsyscall_gtod_data.seq); + + /* copy vsyscall data */ + fsyscall_gtod_data.clk_mask = tk->tkr_mono.mask; + fsyscall_gtod_data.clk_mult = tk->tkr_mono.mult; + fsyscall_gtod_data.clk_shift = tk->tkr_mono.shift; + fsyscall_gtod_data.clk_fsys_mmio = tk->tkr_mono.clock->archdata.fsys_mmio; + fsyscall_gtod_data.clk_cycle_last = tk->tkr_mono.cycle_last; + + fsyscall_gtod_data.wall_time.sec = tk->xtime_sec; + fsyscall_gtod_data.wall_time.snsec = tk->tkr_mono.xtime_nsec; + + fsyscall_gtod_data.monotonic_time.sec = tk->xtime_sec + + tk->wall_to_monotonic.tv_sec; + fsyscall_gtod_data.monotonic_time.snsec = tk->tkr_mono.xtime_nsec + + ((u64)tk->wall_to_monotonic.tv_nsec + << tk->tkr_mono.shift); + + /* normalize */ + while (fsyscall_gtod_data.monotonic_time.snsec >= + (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { + fsyscall_gtod_data.monotonic_time.snsec -= + ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift; + fsyscall_gtod_data.monotonic_time.sec++; + } + + write_seqcount_end(&fsyscall_gtod_data.seq); +} + |