// SPDX-License-Identifier: GPL-2.0/* *    Time of day based timer functions. * *  S390 version *    Copyright IBM Corp. 1999, 2008 *    Author(s): Hartmut Penner (hp@de.ibm.com), *               Martin Schwidefsky (schwidefsky@de.ibm.com), *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) * *  Derived from "arch/i386/kernel/time.c" *    Copyright (C) 1991, 1992, 1995  Linus Torvalds */ #define pr_fmt(fmt) "time: " fmt #include <linux/kernel_stat.h>#include <linux/errno.h>#include <linux/export.h>#include <linux/sched.h>#include <linux/sched/clock.h>#include <linux/kernel.h>#include <linux/param.h>#include <linux/string.h>#include <linux/mm.h>#include <linux/interrupt.h>#include <linux/cpu.h>#include <linux/stop_machine.h>#include <linux/time.h>#include <linux/device.h>#include <linux/delay.h>#include <linux/init.h>#include <linux/smp.h>#include <linux/types.h>#include <linux/profile.h>#include <linux/timex.h>#include <linux/notifier.h>#include <linux/clockchips.h>#include <linux/gfp.h>#include <linux/kprobes.h>#include <linux/uaccess.h>#include <vdso/vsyscall.h>#include <vdso/clocksource.h>#include <vdso/helpers.h>#include <asm/facility.h>#include <asm/delay.h>#include <asm/div64.h>#include <asm/vdso.h>#include <asm/irq.h>#include <asm/irq_regs.h>#include <asm/vtimer.h>#include <asm/stp.h>#include <asm/cio.h>#include "entry.h" union tod_clock __bootdata_preserved(tod_clock_base);EXPORT_SYMBOL_GPL(tod_clock_base); u64 __bootdata_preserved(clock_comparator_max);EXPORT_SYMBOL_GPL(clock_comparator_max); static DEFINE_PER_CPU(struct clock_event_device, comparators); ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);EXPORT_SYMBOL(s390_epoch_delta_notifier); unsigned char ptff_function_mask[16];EXPORT_SYMBOL(ptff_function_mask); static unsigned long lpar_offset;static unsigned long initial_leap_seconds; /* * Get time offsets with PTFF */void __init time_early_init(void){	struct ptff_qto qto;	struct ptff_qui qui; 	vdso_k_time_data->arch_data.tod_delta = tod_clock_base.tod; 	if (!test_facility(28))		return; 	ptff(&ptff_function_mask, sizeof(ptff_function_mask), PTFF_QAF); 	/* get LPAR offset */	if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)		lpar_offset = qto.tod_epoch_difference; 	/* get initial leap seconds */	if (ptff_query(PTFF_QUI) && ptff(&qui, sizeof(qui), PTFF_QUI) == 0)		initial_leap_seconds = (unsigned long)			((long) qui.old_leap * 4096000000L);} unsigned long long noinstr sched_clock_noinstr(void){	return tod_to_ns(__get_tod_clock_monotonic());} /* * Scheduler clock - returns current time in nanosec units. */unsigned long long notrace sched_clock(void){	return tod_to_ns(get_tod_clock_monotonic());}NOKPROBE_SYMBOL(sched_clock); static void ext_to_timespec64(union tod_clock *clk, struct timespec64 *xt){	unsigned long rem, sec, nsec; 	sec = clk->us;	rem = do_div(sec, 1000000);	nsec = ((clk->sus + (rem << 12)) * 125) >> 9;	xt->tv_sec = sec;	xt->tv_nsec = nsec;} void clock_comparator_work(void){	struct clock_event_device *cd; 	get_lowcore()->clock_comparator = clock_comparator_max;	cd = this_cpu_ptr(&comparators);	cd->event_handler(cd);} static int s390_next_event(unsigned long delta,			   struct clock_event_device *evt){	get_lowcore()->clock_comparator = get_tod_clock() + delta;	set_clock_comparator(get_lowcore()->clock_comparator);	return 0;} /* * Set up lowcore and control register of the current cpu to * enable TOD clock and clock comparator interrupts. */void init_cpu_timer(void){	struct clock_event_device *cd;	int cpu; 	get_lowcore()->clock_comparator = clock_comparator_max;	set_clock_comparator(get_lowcore()->clock_comparator); 	cpu = smp_processor_id();	cd = &per_cpu(comparators, cpu);	cd->name		= "comparator";	cd->features		= CLOCK_EVT_FEAT_ONESHOT;	cd->mult		= 16777;	cd->shift		= 12;	cd->min_delta_ns	= 1;	cd->min_delta_ticks	= 1;	cd->max_delta_ns	= LONG_MAX;	cd->max_delta_ticks	= ULONG_MAX;	cd->rating		= 400;	cd->cpumask		= cpumask_of(cpu);	cd->set_next_event	= s390_next_event; 	clockevents_register_device(cd); 	/* Enable clock comparator timer interrupt. */	local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SUBMASK_BIT); 	/* Always allow the timing alert external interrupt. */	local_ctl_set_bit(0, CR0_ETR_SUBMASK_BIT);} static void clock_comparator_interrupt(struct ext_code ext_code,				       unsigned int param32,				       unsigned long param64){	inc_irq_stat(IRQEXT_CLK);	if (get_lowcore()->clock_comparator == clock_comparator_max)		set_clock_comparator(get_lowcore()->clock_comparator);} static void stp_timing_alert(struct stp_irq_parm *); static void timing_alert_interrupt(struct ext_code ext_code,				   unsigned int param32, unsigned long param64){	inc_irq_stat(IRQEXT_TLA);	if (param32 & 0x00038000)		stp_timing_alert((struct stp_irq_parm *) &param32);} static void stp_reset(void); void read_persistent_clock64(struct timespec64 *ts){	union tod_clock clk;	u64 delta; 	delta = initial_leap_seconds + TOD_UNIX_EPOCH;	store_tod_clock_ext(&clk);	clk.eitod -= delta;	ext_to_timespec64(&clk, ts);} void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,						 struct timespec64 *boot_offset){	struct timespec64 boot_time;	union tod_clock clk;	u64 delta; 	delta = initial_leap_seconds + TOD_UNIX_EPOCH;	clk = tod_clock_base;	clk.eitod -= delta;	ext_to_timespec64(&clk, &boot_time); 	read_persistent_clock64(wall_time);	*boot_offset = timespec64_sub(*wall_time, boot_time);} static u64 read_tod_clock(struct clocksource *cs){	return get_tod_clock_monotonic();} static struct clocksource clocksource_tod = {	.name		= "tod",	.rating		= 400,	.read		= read_tod_clock,	.mask		= CLOCKSOURCE_MASK(64),	.mult		= 4096000,	.shift		= 24,	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,	.vdso_clock_mode = VDSO_CLOCKMODE_TOD,	.id		= CSID_S390_TOD,}; struct clocksource * __init clocksource_default_clock(void){	return &clocksource_tod;} /* * Initialize the TOD clock and the CPU timer of * the boot cpu. */void __init time_init(void){	/* Reset time synchronization interfaces. */	stp_reset(); 	/* request the clock comparator external interrupt */	if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))		panic("Couldn't request external interrupt 0x1004"); 	/* request the timing alert external interrupt */	if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))		panic("Couldn't request external interrupt 0x1406"); 	if (__clocksource_register(&clocksource_tod) != 0)		panic("Could not register TOD clock source"); 	/* Enable TOD clock interrupts on the boot cpu. */	init_cpu_timer(); 	/* Enable cpu timer interrupts on the boot cpu. */	vtime_init();} static DEFINE_PER_CPU(atomic_t, clock_sync_word);static DEFINE_MUTEX(stp_mutex);static unsigned long clock_sync_flags; #define CLOCK_SYNC_HAS_STP		0#define CLOCK_SYNC_STP			1#define CLOCK_SYNC_STPINFO_VALID	2 /* * The get_clock function for the physical clock. It will get the current * TOD clock, subtract the LPAR offset and write the result to *clock. * The function returns 0 if the clock is in sync with the external time * source. If the clock mode is local it will return -EOPNOTSUPP and * -EAGAIN if the clock is not in sync with the external reference. */int get_phys_clock(unsigned long *clock){	atomic_t *sw_ptr;	unsigned int sw0, sw1; 	sw_ptr = &get_cpu_var(clock_sync_word);	sw0 = atomic_read(sw_ptr);	*clock = get_tod_clock() - lpar_offset;	sw1 = atomic_read(sw_ptr);	put_cpu_var(clock_sync_word);	if (sw0 == sw1 && (sw0 & 0x80000000U))		/* Success: time is in sync. */		return 0;	if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))		return -EOPNOTSUPP;	if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))		return -EACCES;	return -EAGAIN;}EXPORT_SYMBOL(get_phys_clock); /* * Make get_phys_clock() return -EAGAIN. */static void disable_sync_clock(void *dummy){	atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);	/*	 * Clear the in-sync bit 2^31. All get_phys_clock calls will	 * fail until the sync bit is turned back on. In addition	 * increase the "sequence" counter to avoid the race of an	 * stp event and the complete recovery against get_phys_clock.	 */	atomic_andnot(0x80000000, sw_ptr);	atomic_inc(sw_ptr);} /* * Make get_phys_clock() return 0 again. * Needs to be called from a context disabled for preemption. */static void enable_sync_clock(void){	atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);	atomic_or(0x80000000, sw_ptr);} /* * Function to check if the clock is in sync. */static inline int check_sync_clock(void){	atomic_t *sw_ptr;	int rc; 	sw_ptr = &get_cpu_var(clock_sync_word);	rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;	put_cpu_var(clock_sync_word);	return rc;} /* * Apply clock delta to the global data structures. * This is called once on the CPU that performed the clock sync. */static void clock_sync_global(long delta){	struct ptff_qto qto; 	/* Fixup the monotonic sched clock. */	tod_clock_base.eitod += delta;	vdso_k_time_data->arch_data.tod_delta = tod_clock_base.tod;	/* Update LPAR offset. */	if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)		lpar_offset = qto.tod_epoch_difference;	/* Call the TOD clock change notifier. */	atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0, &delta);} /* * Apply clock delta to the per-CPU data structures of this CPU. * This is called for each online CPU after the call to clock_sync_global. */static void clock_sync_local(long delta){	/* Add the delta to the clock comparator. */	if (get_lowcore()->clock_comparator != clock_comparator_max) {		get_lowcore()->clock_comparator += delta;		set_clock_comparator(get_lowcore()->clock_comparator);	}	/* Adjust the last_update_clock time-stamp. */	get_lowcore()->last_update_clock += delta;} /* Single threaded workqueue used for stp sync events */static struct workqueue_struct *time_sync_wq; static void __init time_init_wq(void){	if (time_sync_wq)		return;	time_sync_wq = create_singlethread_workqueue("timesync");} struct clock_sync_data {	atomic_t cpus;	int in_sync;	long clock_delta;}; /* * Server Time Protocol (STP) code. */static bool stp_online = true;static struct stp_sstpi stp_info;static void *stp_page; static void stp_work_fn(struct work_struct *work);static DECLARE_WORK(stp_work, stp_work_fn);static struct timer_list stp_timer; static int __init early_parse_stp(char *p){	return kstrtobool(p, &stp_online);}early_param("stp", early_parse_stp); /* * Reset STP attachment. */static void __init stp_reset(void){	int rc; 	stp_page = (void *) get_zeroed_page(GFP_ATOMIC);	rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);	if (rc == 0)		set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);	else if (stp_online) {		free_page((unsigned long) stp_page);		stp_page = NULL;		stp_online = false;	}} bool stp_enabled(void){	return test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags) && stp_online;}EXPORT_SYMBOL(stp_enabled); static void stp_timeout(struct timer_list *unused){	queue_work(time_sync_wq, &stp_work);} static int __init stp_init(void){	if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))		return 0;	timer_setup(&stp_timer, stp_timeout, 0);	time_init_wq();	if (!stp_online)		return 0;	queue_work(time_sync_wq, &stp_work);	return 0;} arch_initcall(stp_init); /* * STP timing alert. There are three causes: * 1) timing status change * 2) link availability change * 3) time control parameter change * In all three cases we are only interested in the clock source state. * If a STP clock source is now available use it. */static void stp_timing_alert(struct stp_irq_parm *intparm){	if (intparm->tsc || intparm->lac || intparm->tcpc)		queue_work(time_sync_wq, &stp_work);} /* * STP sync check machine check. This is called when the timing state * changes from the synchronized state to the unsynchronized state. * After a STP sync check the clock is not in sync. The machine check * is broadcasted to all cpus at the same time. */int stp_sync_check(void){	disable_sync_clock(NULL);	return 1;} /* * STP island condition machine check. This is called when an attached * server  attempts to communicate over an STP link and the servers * have matching CTN ids and have a valid stratum-1 configuration * but the configurations do not match. */int stp_island_check(void){	disable_sync_clock(NULL);	return 1;} void stp_queue_work(void){	queue_work(time_sync_wq, &stp_work);} static int __store_stpinfo(void)

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