1 files changed, 462 insertions, 0 deletions

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
new file mode 100644
index 000000000..fa9c0ab8c
--- /dev/null
+++ b/arch/ia64/kernel/time.c
@@ -0,0 +1,462 @@
+// 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/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);
+}
+