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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Time of day based timer functions.
4 *
5 * S390 version
6 * Copyright IBM Corp. 1999, 2008
7 * Author(s): Hartmut Penner (hp@de.ibm.com),
8 * Martin Schwidefsky (schwidefsky@de.ibm.com),
9 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
10 *
11 * Derived from "arch/i386/kernel/time.c"
12 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
13 */
14
15#define KMSG_COMPONENT "time"
16#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
17
18#include <linux/kernel_stat.h>
19#include <linux/errno.h>
20#include <linux/export.h>
21#include <linux/sched.h>
22#include <linux/sched/clock.h>
23#include <linux/kernel.h>
24#include <linux/param.h>
25#include <linux/string.h>
26#include <linux/mm.h>
27#include <linux/interrupt.h>
28#include <linux/cpu.h>
29#include <linux/stop_machine.h>
30#include <linux/time.h>
31#include <linux/device.h>
32#include <linux/delay.h>
33#include <linux/init.h>
34#include <linux/smp.h>
35#include <linux/types.h>
36#include <linux/profile.h>
37#include <linux/timex.h>
38#include <linux/notifier.h>
39#include <linux/timekeeper_internal.h>
40#include <linux/clockchips.h>
41#include <linux/gfp.h>
42#include <linux/kprobes.h>
43#include <linux/uaccess.h>
44#include <vdso/vsyscall.h>
45#include <vdso/clocksource.h>
46#include <vdso/helpers.h>
47#include <asm/facility.h>
48#include <asm/delay.h>
49#include <asm/div64.h>
50#include <asm/vdso.h>
51#include <asm/irq.h>
52#include <asm/irq_regs.h>
53#include <asm/vtimer.h>
54#include <asm/stp.h>
55#include <asm/cio.h>
56#include "entry.h"
57
58union tod_clock tod_clock_base __section(".data");
59EXPORT_SYMBOL_GPL(tod_clock_base);
60
61u64 clock_comparator_max = -1ULL;
62EXPORT_SYMBOL_GPL(clock_comparator_max);
63
64static DEFINE_PER_CPU(struct clock_event_device, comparators);
65
66ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
67EXPORT_SYMBOL(s390_epoch_delta_notifier);
68
69unsigned char ptff_function_mask[16];
70
71static unsigned long lpar_offset;
72static unsigned long initial_leap_seconds;
73static unsigned long tod_steering_end;
74static long tod_steering_delta;
75
76/*
77 * Get time offsets with PTFF
78 */
79void __init time_early_init(void)
80{
81 struct ptff_qto qto;
82 struct ptff_qui qui;
83 int cs;
84
85 /* Initialize TOD steering parameters */
86 tod_steering_end = tod_clock_base.tod;
87 for (cs = 0; cs < CS_BASES; cs++)
88 vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
89
90 if (!test_facility(28))
91 return;
92
93 ptff(&ptff_function_mask, sizeof(ptff_function_mask), PTFF_QAF);
94
95 /* get LPAR offset */
96 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
97 lpar_offset = qto.tod_epoch_difference;
98
99 /* get initial leap seconds */
100 if (ptff_query(PTFF_QUI) && ptff(&qui, sizeof(qui), PTFF_QUI) == 0)
101 initial_leap_seconds = (unsigned long)
102 ((long) qui.old_leap * 4096000000L);
103}
104
105unsigned long long noinstr sched_clock_noinstr(void)
106{
107 return tod_to_ns(__get_tod_clock_monotonic());
108}
109
110/*
111 * Scheduler clock - returns current time in nanosec units.
112 */
113unsigned long long notrace sched_clock(void)
114{
115 return tod_to_ns(get_tod_clock_monotonic());
116}
117NOKPROBE_SYMBOL(sched_clock);
118
119static void ext_to_timespec64(union tod_clock *clk, struct timespec64 *xt)
120{
121 unsigned long rem, sec, nsec;
122
123 sec = clk->us;
124 rem = do_div(sec, 1000000);
125 nsec = ((clk->sus + (rem << 12)) * 125) >> 9;
126 xt->tv_sec = sec;
127 xt->tv_nsec = nsec;
128}
129
130void clock_comparator_work(void)
131{
132 struct clock_event_device *cd;
133
134 S390_lowcore.clock_comparator = clock_comparator_max;
135 cd = this_cpu_ptr(&comparators);
136 cd->event_handler(cd);
137}
138
139static int s390_next_event(unsigned long delta,
140 struct clock_event_device *evt)
141{
142 S390_lowcore.clock_comparator = get_tod_clock() + delta;
143 set_clock_comparator(S390_lowcore.clock_comparator);
144 return 0;
145}
146
147/*
148 * Set up lowcore and control register of the current cpu to
149 * enable TOD clock and clock comparator interrupts.
150 */
151void init_cpu_timer(void)
152{
153 struct clock_event_device *cd;
154 int cpu;
155
156 S390_lowcore.clock_comparator = clock_comparator_max;
157 set_clock_comparator(S390_lowcore.clock_comparator);
158
159 cpu = smp_processor_id();
160 cd = &per_cpu(comparators, cpu);
161 cd->name = "comparator";
162 cd->features = CLOCK_EVT_FEAT_ONESHOT;
163 cd->mult = 16777;
164 cd->shift = 12;
165 cd->min_delta_ns = 1;
166 cd->min_delta_ticks = 1;
167 cd->max_delta_ns = LONG_MAX;
168 cd->max_delta_ticks = ULONG_MAX;
169 cd->rating = 400;
170 cd->cpumask = cpumask_of(cpu);
171 cd->set_next_event = s390_next_event;
172
173 clockevents_register_device(cd);
174
175 /* Enable clock comparator timer interrupt. */
176 local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SUBMASK_BIT);
177
178 /* Always allow the timing alert external interrupt. */
179 local_ctl_set_bit(0, CR0_ETR_SUBMASK_BIT);
180}
181
182static void clock_comparator_interrupt(struct ext_code ext_code,
183 unsigned int param32,
184 unsigned long param64)
185{
186 inc_irq_stat(IRQEXT_CLK);
187 if (S390_lowcore.clock_comparator == clock_comparator_max)
188 set_clock_comparator(S390_lowcore.clock_comparator);
189}
190
191static void stp_timing_alert(struct stp_irq_parm *);
192
193static void timing_alert_interrupt(struct ext_code ext_code,
194 unsigned int param32, unsigned long param64)
195{
196 inc_irq_stat(IRQEXT_TLA);
197 if (param32 & 0x00038000)
198 stp_timing_alert((struct stp_irq_parm *) ¶m32);
199}
200
201static void stp_reset(void);
202
203void read_persistent_clock64(struct timespec64 *ts)
204{
205 union tod_clock clk;
206 u64 delta;
207
208 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
209 store_tod_clock_ext(&clk);
210 clk.eitod -= delta;
211 ext_to_timespec64(&clk, ts);
212}
213
214void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
215 struct timespec64 *boot_offset)
216{
217 struct timespec64 boot_time;
218 union tod_clock clk;
219 u64 delta;
220
221 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
222 clk = tod_clock_base;
223 clk.eitod -= delta;
224 ext_to_timespec64(&clk, &boot_time);
225
226 read_persistent_clock64(wall_time);
227 *boot_offset = timespec64_sub(*wall_time, boot_time);
228}
229
230static u64 read_tod_clock(struct clocksource *cs)
231{
232 unsigned long now, adj;
233
234 preempt_disable(); /* protect from changes to steering parameters */
235 now = get_tod_clock();
236 adj = tod_steering_end - now;
237 if (unlikely((s64) adj > 0))
238 /*
239 * manually steer by 1 cycle every 2^16 cycles. This
240 * corresponds to shifting the tod delta by 15. 1s is
241 * therefore steered in ~9h. The adjust will decrease
242 * over time, until it finally reaches 0.
243 */
244 now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
245 preempt_enable();
246 return now;
247}
248
249static struct clocksource clocksource_tod = {
250 .name = "tod",
251 .rating = 400,
252 .read = read_tod_clock,
253 .mask = CLOCKSOURCE_MASK(64),
254 .mult = 1000,
255 .shift = 12,
256 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
257 .vdso_clock_mode = VDSO_CLOCKMODE_TOD,
258};
259
260struct clocksource * __init clocksource_default_clock(void)
261{
262 return &clocksource_tod;
263}
264
265/*
266 * Initialize the TOD clock and the CPU timer of
267 * the boot cpu.
268 */
269void __init time_init(void)
270{
271 /* Reset time synchronization interfaces. */
272 stp_reset();
273
274 /* request the clock comparator external interrupt */
275 if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
276 panic("Couldn't request external interrupt 0x1004");
277
278 /* request the timing alert external interrupt */
279 if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
280 panic("Couldn't request external interrupt 0x1406");
281
282 if (__clocksource_register(&clocksource_tod) != 0)
283 panic("Could not register TOD clock source");
284
285 /* Enable TOD clock interrupts on the boot cpu. */
286 init_cpu_timer();
287
288 /* Enable cpu timer interrupts on the boot cpu. */
289 vtime_init();
290}
291
292static DEFINE_PER_CPU(atomic_t, clock_sync_word);
293static DEFINE_MUTEX(stp_mutex);
294static unsigned long clock_sync_flags;
295
296#define CLOCK_SYNC_HAS_STP 0
297#define CLOCK_SYNC_STP 1
298#define CLOCK_SYNC_STPINFO_VALID 2
299
300/*
301 * The get_clock function for the physical clock. It will get the current
302 * TOD clock, subtract the LPAR offset and write the result to *clock.
303 * The function returns 0 if the clock is in sync with the external time
304 * source. If the clock mode is local it will return -EOPNOTSUPP and
305 * -EAGAIN if the clock is not in sync with the external reference.
306 */
307int get_phys_clock(unsigned long *clock)
308{
309 atomic_t *sw_ptr;
310 unsigned int sw0, sw1;
311
312 sw_ptr = &get_cpu_var(clock_sync_word);
313 sw0 = atomic_read(sw_ptr);
314 *clock = get_tod_clock() - lpar_offset;
315 sw1 = atomic_read(sw_ptr);
316 put_cpu_var(clock_sync_word);
317 if (sw0 == sw1 && (sw0 & 0x80000000U))
318 /* Success: time is in sync. */
319 return 0;
320 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
321 return -EOPNOTSUPP;
322 if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
323 return -EACCES;
324 return -EAGAIN;
325}
326EXPORT_SYMBOL(get_phys_clock);
327
328/*
329 * Make get_phys_clock() return -EAGAIN.
330 */
331static void disable_sync_clock(void *dummy)
332{
333 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
334 /*
335 * Clear the in-sync bit 2^31. All get_phys_clock calls will
336 * fail until the sync bit is turned back on. In addition
337 * increase the "sequence" counter to avoid the race of an
338 * stp event and the complete recovery against get_phys_clock.
339 */
340 atomic_andnot(0x80000000, sw_ptr);
341 atomic_inc(sw_ptr);
342}
343
344/*
345 * Make get_phys_clock() return 0 again.
346 * Needs to be called from a context disabled for preemption.
347 */
348static void enable_sync_clock(void)
349{
350 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
351 atomic_or(0x80000000, sw_ptr);
352}
353
354/*
355 * Function to check if the clock is in sync.
356 */
357static inline int check_sync_clock(void)
358{
359 atomic_t *sw_ptr;
360 int rc;
361
362 sw_ptr = &get_cpu_var(clock_sync_word);
363 rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
364 put_cpu_var(clock_sync_word);
365 return rc;
366}
367
368/*
369 * Apply clock delta to the global data structures.
370 * This is called once on the CPU that performed the clock sync.
371 */
372static void clock_sync_global(long delta)
373{
374 unsigned long now, adj;
375 struct ptff_qto qto;
376 int cs;
377
378 /* Fixup the monotonic sched clock. */
379 tod_clock_base.eitod += delta;
380 /* Adjust TOD steering parameters. */
381 now = get_tod_clock();
382 adj = tod_steering_end - now;
383 if (unlikely((s64) adj >= 0))
384 /* Calculate how much of the old adjustment is left. */
385 tod_steering_delta = (tod_steering_delta < 0) ?
386 -(adj >> 15) : (adj >> 15);
387 tod_steering_delta += delta;
388 if ((abs(tod_steering_delta) >> 48) != 0)
389 panic("TOD clock sync offset %li is too large to drift\n",
390 tod_steering_delta);
391 tod_steering_end = now + (abs(tod_steering_delta) << 15);
392 for (cs = 0; cs < CS_BASES; cs++) {
393 vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
394 vdso_data[cs].arch_data.tod_steering_delta = tod_steering_delta;
395 }
396
397 /* Update LPAR offset. */
398 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
399 lpar_offset = qto.tod_epoch_difference;
400 /* Call the TOD clock change notifier. */
401 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0, &delta);
402}
403
404/*
405 * Apply clock delta to the per-CPU data structures of this CPU.
406 * This is called for each online CPU after the call to clock_sync_global.
407 */
408static void clock_sync_local(long delta)
409{
410 /* Add the delta to the clock comparator. */
411 if (S390_lowcore.clock_comparator != clock_comparator_max) {
412 S390_lowcore.clock_comparator += delta;
413 set_clock_comparator(S390_lowcore.clock_comparator);
414 }
415 /* Adjust the last_update_clock time-stamp. */
416 S390_lowcore.last_update_clock += delta;
417}
418
419/* Single threaded workqueue used for stp sync events */
420static struct workqueue_struct *time_sync_wq;
421
422static void __init time_init_wq(void)
423{
424 if (time_sync_wq)
425 return;
426 time_sync_wq = create_singlethread_workqueue("timesync");
427}
428
429struct clock_sync_data {
430 atomic_t cpus;
431 int in_sync;
432 long clock_delta;
433};
434
435/*
436 * Server Time Protocol (STP) code.
437 */
438static bool stp_online;
439static struct stp_sstpi stp_info;
440static void *stp_page;
441
442static void stp_work_fn(struct work_struct *work);
443static DECLARE_WORK(stp_work, stp_work_fn);
444static struct timer_list stp_timer;
445
446static int __init early_parse_stp(char *p)
447{
448 return kstrtobool(p, &stp_online);
449}
450early_param("stp", early_parse_stp);
451
452/*
453 * Reset STP attachment.
454 */
455static void __init stp_reset(void)
456{
457 int rc;
458
459 stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
460 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
461 if (rc == 0)
462 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
463 else if (stp_online) {
464 pr_warn("The real or virtual hardware system does not provide an STP interface\n");
465 free_page((unsigned long) stp_page);
466 stp_page = NULL;
467 stp_online = false;
468 }
469}
470
471static void stp_timeout(struct timer_list *unused)
472{
473 queue_work(time_sync_wq, &stp_work);
474}
475
476static int __init stp_init(void)
477{
478 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
479 return 0;
480 timer_setup(&stp_timer, stp_timeout, 0);
481 time_init_wq();
482 if (!stp_online)
483 return 0;
484 queue_work(time_sync_wq, &stp_work);
485 return 0;
486}
487
488arch_initcall(stp_init);
489
490/*
491 * STP timing alert. There are three causes:
492 * 1) timing status change
493 * 2) link availability change
494 * 3) time control parameter change
495 * In all three cases we are only interested in the clock source state.
496 * If a STP clock source is now available use it.
497 */
498static void stp_timing_alert(struct stp_irq_parm *intparm)
499{
500 if (intparm->tsc || intparm->lac || intparm->tcpc)
501 queue_work(time_sync_wq, &stp_work);
502}
503
504/*
505 * STP sync check machine check. This is called when the timing state
506 * changes from the synchronized state to the unsynchronized state.
507 * After a STP sync check the clock is not in sync. The machine check
508 * is broadcasted to all cpus at the same time.
509 */
510int stp_sync_check(void)
511{
512 disable_sync_clock(NULL);
513 return 1;
514}
515
516/*
517 * STP island condition machine check. This is called when an attached
518 * server attempts to communicate over an STP link and the servers
519 * have matching CTN ids and have a valid stratum-1 configuration
520 * but the configurations do not match.
521 */
522int stp_island_check(void)
523{
524 disable_sync_clock(NULL);
525 return 1;
526}
527
528void stp_queue_work(void)
529{
530 queue_work(time_sync_wq, &stp_work);
531}
532
533static int __store_stpinfo(void)
534{
535 int rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
536
537 if (rc)
538 clear_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
539 else
540 set_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
541 return rc;
542}
543
544static int stpinfo_valid(void)
545{
546 return stp_online && test_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
547}
548
549static int stp_sync_clock(void *data)
550{
551 struct clock_sync_data *sync = data;
552 long clock_delta, flags;
553 static int first;
554 int rc;
555
556 enable_sync_clock();
557 if (xchg(&first, 1) == 0) {
558 /* Wait until all other cpus entered the sync function. */
559 while (atomic_read(&sync->cpus) != 0)
560 cpu_relax();
561 rc = 0;
562 if (stp_info.todoff || stp_info.tmd != 2) {
563 flags = vdso_update_begin();
564 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
565 &clock_delta);
566 if (rc == 0) {
567 sync->clock_delta = clock_delta;
568 clock_sync_global(clock_delta);
569 rc = __store_stpinfo();
570 if (rc == 0 && stp_info.tmd != 2)
571 rc = -EAGAIN;
572 }
573 vdso_update_end(flags);
574 }
575 sync->in_sync = rc ? -EAGAIN : 1;
576 xchg(&first, 0);
577 } else {
578 /* Slave */
579 atomic_dec(&sync->cpus);
580 /* Wait for in_sync to be set. */
581 while (READ_ONCE(sync->in_sync) == 0)
582 __udelay(1);
583 }
584 if (sync->in_sync != 1)
585 /* Didn't work. Clear per-cpu in sync bit again. */
586 disable_sync_clock(NULL);
587 /* Apply clock delta to per-CPU fields of this CPU. */
588 clock_sync_local(sync->clock_delta);
589
590 return 0;
591}
592
593static int stp_clear_leap(void)
594{
595 struct __kernel_timex txc;
596 int ret;
597
598 memset(&txc, 0, sizeof(txc));
599
600 ret = do_adjtimex(&txc);
601 if (ret < 0)
602 return ret;
603
604 txc.modes = ADJ_STATUS;
605 txc.status &= ~(STA_INS|STA_DEL);
606 return do_adjtimex(&txc);
607}
608
609static void stp_check_leap(void)
610{
611 struct stp_stzi stzi;
612 struct stp_lsoib *lsoib = &stzi.lsoib;
613 struct __kernel_timex txc;
614 int64_t timediff;
615 int leapdiff, ret;
616
617 if (!stp_info.lu || !check_sync_clock()) {
618 /*
619 * Either a scheduled leap second was removed by the operator,
620 * or STP is out of sync. In both cases, clear the leap second
621 * kernel flags.
622 */
623 if (stp_clear_leap() < 0)
624 pr_err("failed to clear leap second flags\n");
625 return;
626 }
627
628 if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) {
629 pr_err("stzi failed\n");
630 return;
631 }
632
633 timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC;
634 leapdiff = lsoib->nlso - lsoib->also;
635
636 if (leapdiff != 1 && leapdiff != -1) {
637 pr_err("Cannot schedule %d leap seconds\n", leapdiff);
638 return;
639 }
640
641 if (timediff < 0) {
642 if (stp_clear_leap() < 0)
643 pr_err("failed to clear leap second flags\n");
644 } else if (timediff < 7200) {
645 memset(&txc, 0, sizeof(txc));
646 ret = do_adjtimex(&txc);
647 if (ret < 0)
648 return;
649
650 txc.modes = ADJ_STATUS;
651 if (leapdiff > 0)
652 txc.status |= STA_INS;
653 else
654 txc.status |= STA_DEL;
655 ret = do_adjtimex(&txc);
656 if (ret < 0)
657 pr_err("failed to set leap second flags\n");
658 /* arm Timer to clear leap second flags */
659 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(14400 * MSEC_PER_SEC));
660 } else {
661 /* The day the leap second is scheduled for hasn't been reached. Retry
662 * in one hour.
663 */
664 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(3600 * MSEC_PER_SEC));
665 }
666}
667
668/*
669 * STP work. Check for the STP state and take over the clock
670 * synchronization if the STP clock source is usable.
671 */
672static void stp_work_fn(struct work_struct *work)
673{
674 struct clock_sync_data stp_sync;
675 int rc;
676
677 /* prevent multiple execution. */
678 mutex_lock(&stp_mutex);
679
680 if (!stp_online) {
681 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
682 del_timer_sync(&stp_timer);
683 goto out_unlock;
684 }
685
686 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xf0e0, NULL);
687 if (rc)
688 goto out_unlock;
689
690 rc = __store_stpinfo();
691 if (rc || stp_info.c == 0)
692 goto out_unlock;
693
694 /* Skip synchronization if the clock is already in sync. */
695 if (!check_sync_clock()) {
696 memset(&stp_sync, 0, sizeof(stp_sync));
697 cpus_read_lock();
698 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
699 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
700 cpus_read_unlock();
701 }
702
703 if (!check_sync_clock())
704 /*
705 * There is a usable clock but the synchronization failed.
706 * Retry after a second.
707 */
708 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
709 else if (stp_info.lu)
710 stp_check_leap();
711
712out_unlock:
713 mutex_unlock(&stp_mutex);
714}
715
716/*
717 * STP subsys sysfs interface functions
718 */
719static struct bus_type stp_subsys = {
720 .name = "stp",
721 .dev_name = "stp",
722};
723
724static ssize_t ctn_id_show(struct device *dev,
725 struct device_attribute *attr,
726 char *buf)
727{
728 ssize_t ret = -ENODATA;
729
730 mutex_lock(&stp_mutex);
731 if (stpinfo_valid())
732 ret = sprintf(buf, "%016lx\n",
733 *(unsigned long *) stp_info.ctnid);
734 mutex_unlock(&stp_mutex);
735 return ret;
736}
737
738static DEVICE_ATTR_RO(ctn_id);
739
740static ssize_t ctn_type_show(struct device *dev,
741 struct device_attribute *attr,
742 char *buf)
743{
744 ssize_t ret = -ENODATA;
745
746 mutex_lock(&stp_mutex);
747 if (stpinfo_valid())
748 ret = sprintf(buf, "%i\n", stp_info.ctn);
749 mutex_unlock(&stp_mutex);
750 return ret;
751}
752
753static DEVICE_ATTR_RO(ctn_type);
754
755static ssize_t dst_offset_show(struct device *dev,
756 struct device_attribute *attr,
757 char *buf)
758{
759 ssize_t ret = -ENODATA;
760
761 mutex_lock(&stp_mutex);
762 if (stpinfo_valid() && (stp_info.vbits & 0x2000))
763 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
764 mutex_unlock(&stp_mutex);
765 return ret;
766}
767
768static DEVICE_ATTR_RO(dst_offset);
769
770static ssize_t leap_seconds_show(struct device *dev,
771 struct device_attribute *attr,
772 char *buf)
773{
774 ssize_t ret = -ENODATA;
775
776 mutex_lock(&stp_mutex);
777 if (stpinfo_valid() && (stp_info.vbits & 0x8000))
778 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
779 mutex_unlock(&stp_mutex);
780 return ret;
781}
782
783static DEVICE_ATTR_RO(leap_seconds);
784
785static ssize_t leap_seconds_scheduled_show(struct device *dev,
786 struct device_attribute *attr,
787 char *buf)
788{
789 struct stp_stzi stzi;
790 ssize_t ret;
791
792 mutex_lock(&stp_mutex);
793 if (!stpinfo_valid() || !(stp_info.vbits & 0x8000) || !stp_info.lu) {
794 mutex_unlock(&stp_mutex);
795 return -ENODATA;
796 }
797
798 ret = chsc_stzi(stp_page, &stzi, sizeof(stzi));
799 mutex_unlock(&stp_mutex);
800 if (ret < 0)
801 return ret;
802
803 if (!stzi.lsoib.p)
804 return sprintf(buf, "0,0\n");
805
806 return sprintf(buf, "%lu,%d\n",
807 tod_to_ns(stzi.lsoib.nlsout - TOD_UNIX_EPOCH) / NSEC_PER_SEC,
808 stzi.lsoib.nlso - stzi.lsoib.also);
809}
810
811static DEVICE_ATTR_RO(leap_seconds_scheduled);
812
813static ssize_t stratum_show(struct device *dev,
814 struct device_attribute *attr,
815 char *buf)
816{
817 ssize_t ret = -ENODATA;
818
819 mutex_lock(&stp_mutex);
820 if (stpinfo_valid())
821 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
822 mutex_unlock(&stp_mutex);
823 return ret;
824}
825
826static DEVICE_ATTR_RO(stratum);
827
828static ssize_t time_offset_show(struct device *dev,
829 struct device_attribute *attr,
830 char *buf)
831{
832 ssize_t ret = -ENODATA;
833
834 mutex_lock(&stp_mutex);
835 if (stpinfo_valid() && (stp_info.vbits & 0x0800))
836 ret = sprintf(buf, "%i\n", (int) stp_info.tto);
837 mutex_unlock(&stp_mutex);
838 return ret;
839}
840
841static DEVICE_ATTR_RO(time_offset);
842
843static ssize_t time_zone_offset_show(struct device *dev,
844 struct device_attribute *attr,
845 char *buf)
846{
847 ssize_t ret = -ENODATA;
848
849 mutex_lock(&stp_mutex);
850 if (stpinfo_valid() && (stp_info.vbits & 0x4000))
851 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
852 mutex_unlock(&stp_mutex);
853 return ret;
854}
855
856static DEVICE_ATTR_RO(time_zone_offset);
857
858static ssize_t timing_mode_show(struct device *dev,
859 struct device_attribute *attr,
860 char *buf)
861{
862 ssize_t ret = -ENODATA;
863
864 mutex_lock(&stp_mutex);
865 if (stpinfo_valid())
866 ret = sprintf(buf, "%i\n", stp_info.tmd);
867 mutex_unlock(&stp_mutex);
868 return ret;
869}
870
871static DEVICE_ATTR_RO(timing_mode);
872
873static ssize_t timing_state_show(struct device *dev,
874 struct device_attribute *attr,
875 char *buf)
876{
877 ssize_t ret = -ENODATA;
878
879 mutex_lock(&stp_mutex);
880 if (stpinfo_valid())
881 ret = sprintf(buf, "%i\n", stp_info.tst);
882 mutex_unlock(&stp_mutex);
883 return ret;
884}
885
886static DEVICE_ATTR_RO(timing_state);
887
888static ssize_t online_show(struct device *dev,
889 struct device_attribute *attr,
890 char *buf)
891{
892 return sprintf(buf, "%i\n", stp_online);
893}
894
895static ssize_t online_store(struct device *dev,
896 struct device_attribute *attr,
897 const char *buf, size_t count)
898{
899 unsigned int value;
900
901 value = simple_strtoul(buf, NULL, 0);
902 if (value != 0 && value != 1)
903 return -EINVAL;
904 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
905 return -EOPNOTSUPP;
906 mutex_lock(&stp_mutex);
907 stp_online = value;
908 if (stp_online)
909 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
910 else
911 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
912 queue_work(time_sync_wq, &stp_work);
913 mutex_unlock(&stp_mutex);
914 return count;
915}
916
917/*
918 * Can't use DEVICE_ATTR because the attribute should be named
919 * stp/online but dev_attr_online already exists in this file ..
920 */
921static DEVICE_ATTR_RW(online);
922
923static struct attribute *stp_dev_attrs[] = {
924 &dev_attr_ctn_id.attr,
925 &dev_attr_ctn_type.attr,
926 &dev_attr_dst_offset.attr,
927 &dev_attr_leap_seconds.attr,
928 &dev_attr_online.attr,
929 &dev_attr_leap_seconds_scheduled.attr,
930 &dev_attr_stratum.attr,
931 &dev_attr_time_offset.attr,
932 &dev_attr_time_zone_offset.attr,
933 &dev_attr_timing_mode.attr,
934 &dev_attr_timing_state.attr,
935 NULL
936};
937ATTRIBUTE_GROUPS(stp_dev);
938
939static int __init stp_init_sysfs(void)
940{
941 return subsys_system_register(&stp_subsys, stp_dev_groups);
942}
943
944device_initcall(stp_init_sysfs);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Time of day based timer functions.
4 *
5 * S390 version
6 * Copyright IBM Corp. 1999, 2008
7 * Author(s): Hartmut Penner (hp@de.ibm.com),
8 * Martin Schwidefsky (schwidefsky@de.ibm.com),
9 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
10 *
11 * Derived from "arch/i386/kernel/time.c"
12 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
13 */
14
15#define KMSG_COMPONENT "time"
16#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
17
18#include <linux/kernel_stat.h>
19#include <linux/errno.h>
20#include <linux/export.h>
21#include <linux/sched.h>
22#include <linux/sched/clock.h>
23#include <linux/kernel.h>
24#include <linux/param.h>
25#include <linux/string.h>
26#include <linux/mm.h>
27#include <linux/interrupt.h>
28#include <linux/cpu.h>
29#include <linux/stop_machine.h>
30#include <linux/time.h>
31#include <linux/device.h>
32#include <linux/delay.h>
33#include <linux/init.h>
34#include <linux/smp.h>
35#include <linux/types.h>
36#include <linux/profile.h>
37#include <linux/timex.h>
38#include <linux/notifier.h>
39#include <linux/timekeeper_internal.h>
40#include <linux/clockchips.h>
41#include <linux/gfp.h>
42#include <linux/kprobes.h>
43#include <linux/uaccess.h>
44#include <asm/facility.h>
45#include <asm/delay.h>
46#include <asm/div64.h>
47#include <asm/vdso.h>
48#include <asm/irq.h>
49#include <asm/irq_regs.h>
50#include <asm/vtimer.h>
51#include <asm/stp.h>
52#include <asm/cio.h>
53#include "entry.h"
54
55unsigned char tod_clock_base[16] __aligned(8) = {
56 /* Force to data section. */
57 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
58 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
59};
60EXPORT_SYMBOL_GPL(tod_clock_base);
61
62u64 clock_comparator_max = -1ULL;
63EXPORT_SYMBOL_GPL(clock_comparator_max);
64
65static DEFINE_PER_CPU(struct clock_event_device, comparators);
66
67ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
68EXPORT_SYMBOL(s390_epoch_delta_notifier);
69
70unsigned char ptff_function_mask[16];
71
72static unsigned long long lpar_offset;
73static unsigned long long initial_leap_seconds;
74static unsigned long long tod_steering_end;
75static long long tod_steering_delta;
76
77/*
78 * Get time offsets with PTFF
79 */
80void __init time_early_init(void)
81{
82 struct ptff_qto qto;
83 struct ptff_qui qui;
84
85 /* Initialize TOD steering parameters */
86 tod_steering_end = *(unsigned long long *) &tod_clock_base[1];
87 vdso_data->ts_end = tod_steering_end;
88
89 if (!test_facility(28))
90 return;
91
92 ptff(&ptff_function_mask, sizeof(ptff_function_mask), PTFF_QAF);
93
94 /* get LPAR offset */
95 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
96 lpar_offset = qto.tod_epoch_difference;
97
98 /* get initial leap seconds */
99 if (ptff_query(PTFF_QUI) && ptff(&qui, sizeof(qui), PTFF_QUI) == 0)
100 initial_leap_seconds = (unsigned long long)
101 ((long) qui.old_leap * 4096000000L);
102}
103
104/*
105 * Scheduler clock - returns current time in nanosec units.
106 */
107unsigned long long notrace sched_clock(void)
108{
109 return tod_to_ns(get_tod_clock_monotonic());
110}
111NOKPROBE_SYMBOL(sched_clock);
112
113/*
114 * Monotonic_clock - returns # of nanoseconds passed since time_init()
115 */
116unsigned long long monotonic_clock(void)
117{
118 return sched_clock();
119}
120EXPORT_SYMBOL(monotonic_clock);
121
122static void ext_to_timespec64(unsigned char *clk, struct timespec64 *xt)
123{
124 unsigned long long high, low, rem, sec, nsec;
125
126 /* Split extendnd TOD clock to micro-seconds and sub-micro-seconds */
127 high = (*(unsigned long long *) clk) >> 4;
128 low = (*(unsigned long long *)&clk[7]) << 4;
129 /* Calculate seconds and nano-seconds */
130 sec = high;
131 rem = do_div(sec, 1000000);
132 nsec = (((low >> 32) + (rem << 32)) * 1000) >> 32;
133
134 xt->tv_sec = sec;
135 xt->tv_nsec = nsec;
136}
137
138void clock_comparator_work(void)
139{
140 struct clock_event_device *cd;
141
142 S390_lowcore.clock_comparator = clock_comparator_max;
143 cd = this_cpu_ptr(&comparators);
144 cd->event_handler(cd);
145}
146
147static int s390_next_event(unsigned long delta,
148 struct clock_event_device *evt)
149{
150 S390_lowcore.clock_comparator = get_tod_clock() + delta;
151 set_clock_comparator(S390_lowcore.clock_comparator);
152 return 0;
153}
154
155/*
156 * Set up lowcore and control register of the current cpu to
157 * enable TOD clock and clock comparator interrupts.
158 */
159void init_cpu_timer(void)
160{
161 struct clock_event_device *cd;
162 int cpu;
163
164 S390_lowcore.clock_comparator = clock_comparator_max;
165 set_clock_comparator(S390_lowcore.clock_comparator);
166
167 cpu = smp_processor_id();
168 cd = &per_cpu(comparators, cpu);
169 cd->name = "comparator";
170 cd->features = CLOCK_EVT_FEAT_ONESHOT;
171 cd->mult = 16777;
172 cd->shift = 12;
173 cd->min_delta_ns = 1;
174 cd->min_delta_ticks = 1;
175 cd->max_delta_ns = LONG_MAX;
176 cd->max_delta_ticks = ULONG_MAX;
177 cd->rating = 400;
178 cd->cpumask = cpumask_of(cpu);
179 cd->set_next_event = s390_next_event;
180
181 clockevents_register_device(cd);
182
183 /* Enable clock comparator timer interrupt. */
184 __ctl_set_bit(0,11);
185
186 /* Always allow the timing alert external interrupt. */
187 __ctl_set_bit(0, 4);
188}
189
190static void clock_comparator_interrupt(struct ext_code ext_code,
191 unsigned int param32,
192 unsigned long param64)
193{
194 inc_irq_stat(IRQEXT_CLK);
195 if (S390_lowcore.clock_comparator == clock_comparator_max)
196 set_clock_comparator(S390_lowcore.clock_comparator);
197}
198
199static void stp_timing_alert(struct stp_irq_parm *);
200
201static void timing_alert_interrupt(struct ext_code ext_code,
202 unsigned int param32, unsigned long param64)
203{
204 inc_irq_stat(IRQEXT_TLA);
205 if (param32 & 0x00038000)
206 stp_timing_alert((struct stp_irq_parm *) ¶m32);
207}
208
209static void stp_reset(void);
210
211void read_persistent_clock64(struct timespec64 *ts)
212{
213 unsigned char clk[STORE_CLOCK_EXT_SIZE];
214 __u64 delta;
215
216 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
217 get_tod_clock_ext(clk);
218 *(__u64 *) &clk[1] -= delta;
219 if (*(__u64 *) &clk[1] > delta)
220 clk[0]--;
221 ext_to_timespec64(clk, ts);
222}
223
224void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
225 struct timespec64 *boot_offset)
226{
227 unsigned char clk[STORE_CLOCK_EXT_SIZE];
228 struct timespec64 boot_time;
229 __u64 delta;
230
231 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
232 memcpy(clk, tod_clock_base, STORE_CLOCK_EXT_SIZE);
233 *(__u64 *)&clk[1] -= delta;
234 if (*(__u64 *)&clk[1] > delta)
235 clk[0]--;
236 ext_to_timespec64(clk, &boot_time);
237
238 read_persistent_clock64(wall_time);
239 *boot_offset = timespec64_sub(*wall_time, boot_time);
240}
241
242static u64 read_tod_clock(struct clocksource *cs)
243{
244 unsigned long long now, adj;
245
246 preempt_disable(); /* protect from changes to steering parameters */
247 now = get_tod_clock();
248 adj = tod_steering_end - now;
249 if (unlikely((s64) adj >= 0))
250 /*
251 * manually steer by 1 cycle every 2^16 cycles. This
252 * corresponds to shifting the tod delta by 15. 1s is
253 * therefore steered in ~9h. The adjust will decrease
254 * over time, until it finally reaches 0.
255 */
256 now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
257 preempt_enable();
258 return now;
259}
260
261static struct clocksource clocksource_tod = {
262 .name = "tod",
263 .rating = 400,
264 .read = read_tod_clock,
265 .mask = -1ULL,
266 .mult = 1000,
267 .shift = 12,
268 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
269};
270
271struct clocksource * __init clocksource_default_clock(void)
272{
273 return &clocksource_tod;
274}
275
276void update_vsyscall(struct timekeeper *tk)
277{
278 u64 nsecps;
279
280 if (tk->tkr_mono.clock != &clocksource_tod)
281 return;
282
283 /* Make userspace gettimeofday spin until we're done. */
284 ++vdso_data->tb_update_count;
285 smp_wmb();
286 vdso_data->xtime_tod_stamp = tk->tkr_mono.cycle_last;
287 vdso_data->xtime_clock_sec = tk->xtime_sec;
288 vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
289 vdso_data->wtom_clock_sec =
290 tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
291 vdso_data->wtom_clock_nsec = tk->tkr_mono.xtime_nsec +
292 + ((u64) tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
293 nsecps = (u64) NSEC_PER_SEC << tk->tkr_mono.shift;
294 while (vdso_data->wtom_clock_nsec >= nsecps) {
295 vdso_data->wtom_clock_nsec -= nsecps;
296 vdso_data->wtom_clock_sec++;
297 }
298
299 vdso_data->xtime_coarse_sec = tk->xtime_sec;
300 vdso_data->xtime_coarse_nsec =
301 (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
302 vdso_data->wtom_coarse_sec =
303 vdso_data->xtime_coarse_sec + tk->wall_to_monotonic.tv_sec;
304 vdso_data->wtom_coarse_nsec =
305 vdso_data->xtime_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
306 while (vdso_data->wtom_coarse_nsec >= NSEC_PER_SEC) {
307 vdso_data->wtom_coarse_nsec -= NSEC_PER_SEC;
308 vdso_data->wtom_coarse_sec++;
309 }
310
311 vdso_data->tk_mult = tk->tkr_mono.mult;
312 vdso_data->tk_shift = tk->tkr_mono.shift;
313 smp_wmb();
314 ++vdso_data->tb_update_count;
315}
316
317extern struct timezone sys_tz;
318
319void update_vsyscall_tz(void)
320{
321 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
322 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
323}
324
325/*
326 * Initialize the TOD clock and the CPU timer of
327 * the boot cpu.
328 */
329void __init time_init(void)
330{
331 /* Reset time synchronization interfaces. */
332 stp_reset();
333
334 /* request the clock comparator external interrupt */
335 if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
336 panic("Couldn't request external interrupt 0x1004");
337
338 /* request the timing alert external interrupt */
339 if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
340 panic("Couldn't request external interrupt 0x1406");
341
342 if (__clocksource_register(&clocksource_tod) != 0)
343 panic("Could not register TOD clock source");
344
345 /* Enable TOD clock interrupts on the boot cpu. */
346 init_cpu_timer();
347
348 /* Enable cpu timer interrupts on the boot cpu. */
349 vtime_init();
350}
351
352static DEFINE_PER_CPU(atomic_t, clock_sync_word);
353static DEFINE_MUTEX(clock_sync_mutex);
354static unsigned long clock_sync_flags;
355
356#define CLOCK_SYNC_HAS_STP 0
357#define CLOCK_SYNC_STP 1
358
359/*
360 * The get_clock function for the physical clock. It will get the current
361 * TOD clock, subtract the LPAR offset and write the result to *clock.
362 * The function returns 0 if the clock is in sync with the external time
363 * source. If the clock mode is local it will return -EOPNOTSUPP and
364 * -EAGAIN if the clock is not in sync with the external reference.
365 */
366int get_phys_clock(unsigned long *clock)
367{
368 atomic_t *sw_ptr;
369 unsigned int sw0, sw1;
370
371 sw_ptr = &get_cpu_var(clock_sync_word);
372 sw0 = atomic_read(sw_ptr);
373 *clock = get_tod_clock() - lpar_offset;
374 sw1 = atomic_read(sw_ptr);
375 put_cpu_var(clock_sync_word);
376 if (sw0 == sw1 && (sw0 & 0x80000000U))
377 /* Success: time is in sync. */
378 return 0;
379 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
380 return -EOPNOTSUPP;
381 if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
382 return -EACCES;
383 return -EAGAIN;
384}
385EXPORT_SYMBOL(get_phys_clock);
386
387/*
388 * Make get_phys_clock() return -EAGAIN.
389 */
390static void disable_sync_clock(void *dummy)
391{
392 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
393 /*
394 * Clear the in-sync bit 2^31. All get_phys_clock calls will
395 * fail until the sync bit is turned back on. In addition
396 * increase the "sequence" counter to avoid the race of an
397 * stp event and the complete recovery against get_phys_clock.
398 */
399 atomic_andnot(0x80000000, sw_ptr);
400 atomic_inc(sw_ptr);
401}
402
403/*
404 * Make get_phys_clock() return 0 again.
405 * Needs to be called from a context disabled for preemption.
406 */
407static void enable_sync_clock(void)
408{
409 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
410 atomic_or(0x80000000, sw_ptr);
411}
412
413/*
414 * Function to check if the clock is in sync.
415 */
416static inline int check_sync_clock(void)
417{
418 atomic_t *sw_ptr;
419 int rc;
420
421 sw_ptr = &get_cpu_var(clock_sync_word);
422 rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
423 put_cpu_var(clock_sync_word);
424 return rc;
425}
426
427/*
428 * Apply clock delta to the global data structures.
429 * This is called once on the CPU that performed the clock sync.
430 */
431static void clock_sync_global(unsigned long long delta)
432{
433 unsigned long now, adj;
434 struct ptff_qto qto;
435
436 /* Fixup the monotonic sched clock. */
437 *(unsigned long long *) &tod_clock_base[1] += delta;
438 if (*(unsigned long long *) &tod_clock_base[1] < delta)
439 /* Epoch overflow */
440 tod_clock_base[0]++;
441 /* Adjust TOD steering parameters. */
442 vdso_data->tb_update_count++;
443 now = get_tod_clock();
444 adj = tod_steering_end - now;
445 if (unlikely((s64) adj >= 0))
446 /* Calculate how much of the old adjustment is left. */
447 tod_steering_delta = (tod_steering_delta < 0) ?
448 -(adj >> 15) : (adj >> 15);
449 tod_steering_delta += delta;
450 if ((abs(tod_steering_delta) >> 48) != 0)
451 panic("TOD clock sync offset %lli is too large to drift\n",
452 tod_steering_delta);
453 tod_steering_end = now + (abs(tod_steering_delta) << 15);
454 vdso_data->ts_dir = (tod_steering_delta < 0) ? 0 : 1;
455 vdso_data->ts_end = tod_steering_end;
456 vdso_data->tb_update_count++;
457 /* Update LPAR offset. */
458 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
459 lpar_offset = qto.tod_epoch_difference;
460 /* Call the TOD clock change notifier. */
461 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0, &delta);
462}
463
464/*
465 * Apply clock delta to the per-CPU data structures of this CPU.
466 * This is called for each online CPU after the call to clock_sync_global.
467 */
468static void clock_sync_local(unsigned long long delta)
469{
470 /* Add the delta to the clock comparator. */
471 if (S390_lowcore.clock_comparator != clock_comparator_max) {
472 S390_lowcore.clock_comparator += delta;
473 set_clock_comparator(S390_lowcore.clock_comparator);
474 }
475 /* Adjust the last_update_clock time-stamp. */
476 S390_lowcore.last_update_clock += delta;
477}
478
479/* Single threaded workqueue used for stp sync events */
480static struct workqueue_struct *time_sync_wq;
481
482static void __init time_init_wq(void)
483{
484 if (time_sync_wq)
485 return;
486 time_sync_wq = create_singlethread_workqueue("timesync");
487}
488
489struct clock_sync_data {
490 atomic_t cpus;
491 int in_sync;
492 unsigned long long clock_delta;
493};
494
495/*
496 * Server Time Protocol (STP) code.
497 */
498static bool stp_online;
499static struct stp_sstpi stp_info;
500static void *stp_page;
501
502static void stp_work_fn(struct work_struct *work);
503static DEFINE_MUTEX(stp_work_mutex);
504static DECLARE_WORK(stp_work, stp_work_fn);
505static struct timer_list stp_timer;
506
507static int __init early_parse_stp(char *p)
508{
509 return kstrtobool(p, &stp_online);
510}
511early_param("stp", early_parse_stp);
512
513/*
514 * Reset STP attachment.
515 */
516static void __init stp_reset(void)
517{
518 int rc;
519
520 stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
521 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
522 if (rc == 0)
523 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
524 else if (stp_online) {
525 pr_warn("The real or virtual hardware system does not provide an STP interface\n");
526 free_page((unsigned long) stp_page);
527 stp_page = NULL;
528 stp_online = false;
529 }
530}
531
532static void stp_timeout(struct timer_list *unused)
533{
534 queue_work(time_sync_wq, &stp_work);
535}
536
537static int __init stp_init(void)
538{
539 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
540 return 0;
541 timer_setup(&stp_timer, stp_timeout, 0);
542 time_init_wq();
543 if (!stp_online)
544 return 0;
545 queue_work(time_sync_wq, &stp_work);
546 return 0;
547}
548
549arch_initcall(stp_init);
550
551/*
552 * STP timing alert. There are three causes:
553 * 1) timing status change
554 * 2) link availability change
555 * 3) time control parameter change
556 * In all three cases we are only interested in the clock source state.
557 * If a STP clock source is now available use it.
558 */
559static void stp_timing_alert(struct stp_irq_parm *intparm)
560{
561 if (intparm->tsc || intparm->lac || intparm->tcpc)
562 queue_work(time_sync_wq, &stp_work);
563}
564
565/*
566 * STP sync check machine check. This is called when the timing state
567 * changes from the synchronized state to the unsynchronized state.
568 * After a STP sync check the clock is not in sync. The machine check
569 * is broadcasted to all cpus at the same time.
570 */
571int stp_sync_check(void)
572{
573 disable_sync_clock(NULL);
574 return 1;
575}
576
577/*
578 * STP island condition machine check. This is called when an attached
579 * server attempts to communicate over an STP link and the servers
580 * have matching CTN ids and have a valid stratum-1 configuration
581 * but the configurations do not match.
582 */
583int stp_island_check(void)
584{
585 disable_sync_clock(NULL);
586 return 1;
587}
588
589void stp_queue_work(void)
590{
591 queue_work(time_sync_wq, &stp_work);
592}
593
594static int stp_sync_clock(void *data)
595{
596 struct clock_sync_data *sync = data;
597 unsigned long long clock_delta;
598 static int first;
599 int rc;
600
601 enable_sync_clock();
602 if (xchg(&first, 1) == 0) {
603 /* Wait until all other cpus entered the sync function. */
604 while (atomic_read(&sync->cpus) != 0)
605 cpu_relax();
606 rc = 0;
607 if (stp_info.todoff[0] || stp_info.todoff[1] ||
608 stp_info.todoff[2] || stp_info.todoff[3] ||
609 stp_info.tmd != 2) {
610 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
611 &clock_delta);
612 if (rc == 0) {
613 sync->clock_delta = clock_delta;
614 clock_sync_global(clock_delta);
615 rc = chsc_sstpi(stp_page, &stp_info,
616 sizeof(struct stp_sstpi));
617 if (rc == 0 && stp_info.tmd != 2)
618 rc = -EAGAIN;
619 }
620 }
621 sync->in_sync = rc ? -EAGAIN : 1;
622 xchg(&first, 0);
623 } else {
624 /* Slave */
625 atomic_dec(&sync->cpus);
626 /* Wait for in_sync to be set. */
627 while (READ_ONCE(sync->in_sync) == 0)
628 __udelay(1);
629 }
630 if (sync->in_sync != 1)
631 /* Didn't work. Clear per-cpu in sync bit again. */
632 disable_sync_clock(NULL);
633 /* Apply clock delta to per-CPU fields of this CPU. */
634 clock_sync_local(sync->clock_delta);
635
636 return 0;
637}
638
639/*
640 * STP work. Check for the STP state and take over the clock
641 * synchronization if the STP clock source is usable.
642 */
643static void stp_work_fn(struct work_struct *work)
644{
645 struct clock_sync_data stp_sync;
646 int rc;
647
648 /* prevent multiple execution. */
649 mutex_lock(&stp_work_mutex);
650
651 if (!stp_online) {
652 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
653 del_timer_sync(&stp_timer);
654 goto out_unlock;
655 }
656
657 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0, NULL);
658 if (rc)
659 goto out_unlock;
660
661 rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
662 if (rc || stp_info.c == 0)
663 goto out_unlock;
664
665 /* Skip synchronization if the clock is already in sync. */
666 if (check_sync_clock())
667 goto out_unlock;
668
669 memset(&stp_sync, 0, sizeof(stp_sync));
670 cpus_read_lock();
671 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
672 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
673 cpus_read_unlock();
674
675 if (!check_sync_clock())
676 /*
677 * There is a usable clock but the synchonization failed.
678 * Retry after a second.
679 */
680 mod_timer(&stp_timer, jiffies + HZ);
681
682out_unlock:
683 mutex_unlock(&stp_work_mutex);
684}
685
686/*
687 * STP subsys sysfs interface functions
688 */
689static struct bus_type stp_subsys = {
690 .name = "stp",
691 .dev_name = "stp",
692};
693
694static ssize_t stp_ctn_id_show(struct device *dev,
695 struct device_attribute *attr,
696 char *buf)
697{
698 if (!stp_online)
699 return -ENODATA;
700 return sprintf(buf, "%016llx\n",
701 *(unsigned long long *) stp_info.ctnid);
702}
703
704static DEVICE_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);
705
706static ssize_t stp_ctn_type_show(struct device *dev,
707 struct device_attribute *attr,
708 char *buf)
709{
710 if (!stp_online)
711 return -ENODATA;
712 return sprintf(buf, "%i\n", stp_info.ctn);
713}
714
715static DEVICE_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);
716
717static ssize_t stp_dst_offset_show(struct device *dev,
718 struct device_attribute *attr,
719 char *buf)
720{
721 if (!stp_online || !(stp_info.vbits & 0x2000))
722 return -ENODATA;
723 return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
724}
725
726static DEVICE_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);
727
728static ssize_t stp_leap_seconds_show(struct device *dev,
729 struct device_attribute *attr,
730 char *buf)
731{
732 if (!stp_online || !(stp_info.vbits & 0x8000))
733 return -ENODATA;
734 return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
735}
736
737static DEVICE_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);
738
739static ssize_t stp_stratum_show(struct device *dev,
740 struct device_attribute *attr,
741 char *buf)
742{
743 if (!stp_online)
744 return -ENODATA;
745 return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
746}
747
748static DEVICE_ATTR(stratum, 0400, stp_stratum_show, NULL);
749
750static ssize_t stp_time_offset_show(struct device *dev,
751 struct device_attribute *attr,
752 char *buf)
753{
754 if (!stp_online || !(stp_info.vbits & 0x0800))
755 return -ENODATA;
756 return sprintf(buf, "%i\n", (int) stp_info.tto);
757}
758
759static DEVICE_ATTR(time_offset, 0400, stp_time_offset_show, NULL);
760
761static ssize_t stp_time_zone_offset_show(struct device *dev,
762 struct device_attribute *attr,
763 char *buf)
764{
765 if (!stp_online || !(stp_info.vbits & 0x4000))
766 return -ENODATA;
767 return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
768}
769
770static DEVICE_ATTR(time_zone_offset, 0400,
771 stp_time_zone_offset_show, NULL);
772
773static ssize_t stp_timing_mode_show(struct device *dev,
774 struct device_attribute *attr,
775 char *buf)
776{
777 if (!stp_online)
778 return -ENODATA;
779 return sprintf(buf, "%i\n", stp_info.tmd);
780}
781
782static DEVICE_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);
783
784static ssize_t stp_timing_state_show(struct device *dev,
785 struct device_attribute *attr,
786 char *buf)
787{
788 if (!stp_online)
789 return -ENODATA;
790 return sprintf(buf, "%i\n", stp_info.tst);
791}
792
793static DEVICE_ATTR(timing_state, 0400, stp_timing_state_show, NULL);
794
795static ssize_t stp_online_show(struct device *dev,
796 struct device_attribute *attr,
797 char *buf)
798{
799 return sprintf(buf, "%i\n", stp_online);
800}
801
802static ssize_t stp_online_store(struct device *dev,
803 struct device_attribute *attr,
804 const char *buf, size_t count)
805{
806 unsigned int value;
807
808 value = simple_strtoul(buf, NULL, 0);
809 if (value != 0 && value != 1)
810 return -EINVAL;
811 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
812 return -EOPNOTSUPP;
813 mutex_lock(&clock_sync_mutex);
814 stp_online = value;
815 if (stp_online)
816 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
817 else
818 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
819 queue_work(time_sync_wq, &stp_work);
820 mutex_unlock(&clock_sync_mutex);
821 return count;
822}
823
824/*
825 * Can't use DEVICE_ATTR because the attribute should be named
826 * stp/online but dev_attr_online already exists in this file ..
827 */
828static struct device_attribute dev_attr_stp_online = {
829 .attr = { .name = "online", .mode = 0600 },
830 .show = stp_online_show,
831 .store = stp_online_store,
832};
833
834static struct device_attribute *stp_attributes[] = {
835 &dev_attr_ctn_id,
836 &dev_attr_ctn_type,
837 &dev_attr_dst_offset,
838 &dev_attr_leap_seconds,
839 &dev_attr_stp_online,
840 &dev_attr_stratum,
841 &dev_attr_time_offset,
842 &dev_attr_time_zone_offset,
843 &dev_attr_timing_mode,
844 &dev_attr_timing_state,
845 NULL
846};
847
848static int __init stp_init_sysfs(void)
849{
850 struct device_attribute **attr;
851 int rc;
852
853 rc = subsys_system_register(&stp_subsys, NULL);
854 if (rc)
855 goto out;
856 for (attr = stp_attributes; *attr; attr++) {
857 rc = device_create_file(stp_subsys.dev_root, *attr);
858 if (rc)
859 goto out_unreg;
860 }
861 return 0;
862out_unreg:
863 for (; attr >= stp_attributes; attr--)
864 device_remove_file(stp_subsys.dev_root, *attr);
865 bus_unregister(&stp_subsys);
866out:
867 return rc;
868}
869
870device_initcall(stp_init_sysfs);