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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/clockchips.h>
40#include <linux/gfp.h>
41#include <linux/kprobes.h>
42#include <linux/uaccess.h>
43#include <vdso/vsyscall.h>
44#include <vdso/clocksource.h>
45#include <vdso/helpers.h>
46#include <asm/facility.h>
47#include <asm/delay.h>
48#include <asm/div64.h>
49#include <asm/vdso.h>
50#include <asm/irq.h>
51#include <asm/irq_regs.h>
52#include <asm/vtimer.h>
53#include <asm/stp.h>
54#include <asm/cio.h>
55#include "entry.h"
56
57union tod_clock tod_clock_base __section(".data");
58EXPORT_SYMBOL_GPL(tod_clock_base);
59
60u64 clock_comparator_max = -1ULL;
61EXPORT_SYMBOL_GPL(clock_comparator_max);
62
63static DEFINE_PER_CPU(struct clock_event_device, comparators);
64
65ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
66EXPORT_SYMBOL(s390_epoch_delta_notifier);
67
68unsigned char ptff_function_mask[16];
69
70static unsigned long lpar_offset;
71static unsigned long initial_leap_seconds;
72static unsigned long tod_steering_end;
73static long tod_steering_delta;
74
75/*
76 * Get time offsets with PTFF
77 */
78void __init time_early_init(void)
79{
80 struct ptff_qto qto;
81 struct ptff_qui qui;
82 int cs;
83
84 /* Initialize TOD steering parameters */
85 tod_steering_end = tod_clock_base.tod;
86 for (cs = 0; cs < CS_BASES; cs++)
87 vdso_data[cs].arch_data.tod_steering_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)
101 ((long) qui.old_leap * 4096000000L);
102}
103
104unsigned long long noinstr sched_clock_noinstr(void)
105{
106 return tod_to_ns(__get_tod_clock_monotonic());
107}
108
109/*
110 * Scheduler clock - returns current time in nanosec units.
111 */
112unsigned long long notrace sched_clock(void)
113{
114 return tod_to_ns(get_tod_clock_monotonic());
115}
116NOKPROBE_SYMBOL(sched_clock);
117
118static void ext_to_timespec64(union tod_clock *clk, struct timespec64 *xt)
119{
120 unsigned long rem, sec, nsec;
121
122 sec = clk->us;
123 rem = do_div(sec, 1000000);
124 nsec = ((clk->sus + (rem << 12)) * 125) >> 9;
125 xt->tv_sec = sec;
126 xt->tv_nsec = nsec;
127}
128
129void clock_comparator_work(void)
130{
131 struct clock_event_device *cd;
132
133 get_lowcore()->clock_comparator = clock_comparator_max;
134 cd = this_cpu_ptr(&comparators);
135 cd->event_handler(cd);
136}
137
138static int s390_next_event(unsigned long delta,
139 struct clock_event_device *evt)
140{
141 get_lowcore()->clock_comparator = get_tod_clock() + delta;
142 set_clock_comparator(get_lowcore()->clock_comparator);
143 return 0;
144}
145
146/*
147 * Set up lowcore and control register of the current cpu to
148 * enable TOD clock and clock comparator interrupts.
149 */
150void init_cpu_timer(void)
151{
152 struct clock_event_device *cd;
153 int cpu;
154
155 get_lowcore()->clock_comparator = clock_comparator_max;
156 set_clock_comparator(get_lowcore()->clock_comparator);
157
158 cpu = smp_processor_id();
159 cd = &per_cpu(comparators, cpu);
160 cd->name = "comparator";
161 cd->features = CLOCK_EVT_FEAT_ONESHOT;
162 cd->mult = 16777;
163 cd->shift = 12;
164 cd->min_delta_ns = 1;
165 cd->min_delta_ticks = 1;
166 cd->max_delta_ns = LONG_MAX;
167 cd->max_delta_ticks = ULONG_MAX;
168 cd->rating = 400;
169 cd->cpumask = cpumask_of(cpu);
170 cd->set_next_event = s390_next_event;
171
172 clockevents_register_device(cd);
173
174 /* Enable clock comparator timer interrupt. */
175 local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SUBMASK_BIT);
176
177 /* Always allow the timing alert external interrupt. */
178 local_ctl_set_bit(0, CR0_ETR_SUBMASK_BIT);
179}
180
181static void clock_comparator_interrupt(struct ext_code ext_code,
182 unsigned int param32,
183 unsigned long param64)
184{
185 inc_irq_stat(IRQEXT_CLK);
186 if (get_lowcore()->clock_comparator == clock_comparator_max)
187 set_clock_comparator(get_lowcore()->clock_comparator);
188}
189
190static void stp_timing_alert(struct stp_irq_parm *);
191
192static void timing_alert_interrupt(struct ext_code ext_code,
193 unsigned int param32, unsigned long param64)
194{
195 inc_irq_stat(IRQEXT_TLA);
196 if (param32 & 0x00038000)
197 stp_timing_alert((struct stp_irq_parm *) ¶m32);
198}
199
200static void stp_reset(void);
201
202void read_persistent_clock64(struct timespec64 *ts)
203{
204 union tod_clock clk;
205 u64 delta;
206
207 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
208 store_tod_clock_ext(&clk);
209 clk.eitod -= delta;
210 ext_to_timespec64(&clk, ts);
211}
212
213void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
214 struct timespec64 *boot_offset)
215{
216 struct timespec64 boot_time;
217 union tod_clock clk;
218 u64 delta;
219
220 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
221 clk = tod_clock_base;
222 clk.eitod -= delta;
223 ext_to_timespec64(&clk, &boot_time);
224
225 read_persistent_clock64(wall_time);
226 *boot_offset = timespec64_sub(*wall_time, boot_time);
227}
228
229static u64 read_tod_clock(struct clocksource *cs)
230{
231 unsigned long now, adj;
232
233 preempt_disable(); /* protect from changes to steering parameters */
234 now = get_tod_clock();
235 adj = tod_steering_end - now;
236 if (unlikely((s64) adj > 0))
237 /*
238 * manually steer by 1 cycle every 2^16 cycles. This
239 * corresponds to shifting the tod delta by 15. 1s is
240 * therefore steered in ~9h. The adjust will decrease
241 * over time, until it finally reaches 0.
242 */
243 now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
244 preempt_enable();
245 return now;
246}
247
248static struct clocksource clocksource_tod = {
249 .name = "tod",
250 .rating = 400,
251 .read = read_tod_clock,
252 .mask = CLOCKSOURCE_MASK(64),
253 .mult = 4096000,
254 .shift = 24,
255 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
256 .vdso_clock_mode = VDSO_CLOCKMODE_TOD,
257 .id = CSID_S390_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 (get_lowcore()->clock_comparator != clock_comparator_max) {
412 get_lowcore()->clock_comparator += delta;
413 set_clock_comparator(get_lowcore()->clock_comparator);
414 }
415 /* Adjust the last_update_clock time-stamp. */
416 get_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
471bool stp_enabled(void)
472{
473 return test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags) && stp_online;
474}
475EXPORT_SYMBOL(stp_enabled);
476
477static void stp_timeout(struct timer_list *unused)
478{
479 queue_work(time_sync_wq, &stp_work);
480}
481
482static int __init stp_init(void)
483{
484 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
485 return 0;
486 timer_setup(&stp_timer, stp_timeout, 0);
487 time_init_wq();
488 if (!stp_online)
489 return 0;
490 queue_work(time_sync_wq, &stp_work);
491 return 0;
492}
493
494arch_initcall(stp_init);
495
496/*
497 * STP timing alert. There are three causes:
498 * 1) timing status change
499 * 2) link availability change
500 * 3) time control parameter change
501 * In all three cases we are only interested in the clock source state.
502 * If a STP clock source is now available use it.
503 */
504static void stp_timing_alert(struct stp_irq_parm *intparm)
505{
506 if (intparm->tsc || intparm->lac || intparm->tcpc)
507 queue_work(time_sync_wq, &stp_work);
508}
509
510/*
511 * STP sync check machine check. This is called when the timing state
512 * changes from the synchronized state to the unsynchronized state.
513 * After a STP sync check the clock is not in sync. The machine check
514 * is broadcasted to all cpus at the same time.
515 */
516int stp_sync_check(void)
517{
518 disable_sync_clock(NULL);
519 return 1;
520}
521
522/*
523 * STP island condition machine check. This is called when an attached
524 * server attempts to communicate over an STP link and the servers
525 * have matching CTN ids and have a valid stratum-1 configuration
526 * but the configurations do not match.
527 */
528int stp_island_check(void)
529{
530 disable_sync_clock(NULL);
531 return 1;
532}
533
534void stp_queue_work(void)
535{
536 queue_work(time_sync_wq, &stp_work);
537}
538
539static int __store_stpinfo(void)
540{
541 int rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
542
543 if (rc)
544 clear_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
545 else
546 set_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
547 return rc;
548}
549
550static int stpinfo_valid(void)
551{
552 return stp_online && test_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
553}
554
555static int stp_sync_clock(void *data)
556{
557 struct clock_sync_data *sync = data;
558 long clock_delta, flags;
559 static int first;
560 int rc;
561
562 enable_sync_clock();
563 if (xchg(&first, 1) == 0) {
564 /* Wait until all other cpus entered the sync function. */
565 while (atomic_read(&sync->cpus) != 0)
566 cpu_relax();
567 rc = 0;
568 if (stp_info.todoff || stp_info.tmd != 2) {
569 flags = vdso_update_begin();
570 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
571 &clock_delta);
572 if (rc == 0) {
573 sync->clock_delta = clock_delta;
574 clock_sync_global(clock_delta);
575 rc = __store_stpinfo();
576 if (rc == 0 && stp_info.tmd != 2)
577 rc = -EAGAIN;
578 }
579 vdso_update_end(flags);
580 }
581 sync->in_sync = rc ? -EAGAIN : 1;
582 xchg(&first, 0);
583 } else {
584 /* Slave */
585 atomic_dec(&sync->cpus);
586 /* Wait for in_sync to be set. */
587 while (READ_ONCE(sync->in_sync) == 0)
588 __udelay(1);
589 }
590 if (sync->in_sync != 1)
591 /* Didn't work. Clear per-cpu in sync bit again. */
592 disable_sync_clock(NULL);
593 /* Apply clock delta to per-CPU fields of this CPU. */
594 clock_sync_local(sync->clock_delta);
595
596 return 0;
597}
598
599static int stp_clear_leap(void)
600{
601 struct __kernel_timex txc;
602 int ret;
603
604 memset(&txc, 0, sizeof(txc));
605
606 ret = do_adjtimex(&txc);
607 if (ret < 0)
608 return ret;
609
610 txc.modes = ADJ_STATUS;
611 txc.status &= ~(STA_INS|STA_DEL);
612 return do_adjtimex(&txc);
613}
614
615static void stp_check_leap(void)
616{
617 struct stp_stzi stzi;
618 struct stp_lsoib *lsoib = &stzi.lsoib;
619 struct __kernel_timex txc;
620 int64_t timediff;
621 int leapdiff, ret;
622
623 if (!stp_info.lu || !check_sync_clock()) {
624 /*
625 * Either a scheduled leap second was removed by the operator,
626 * or STP is out of sync. In both cases, clear the leap second
627 * kernel flags.
628 */
629 if (stp_clear_leap() < 0)
630 pr_err("failed to clear leap second flags\n");
631 return;
632 }
633
634 if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) {
635 pr_err("stzi failed\n");
636 return;
637 }
638
639 timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC;
640 leapdiff = lsoib->nlso - lsoib->also;
641
642 if (leapdiff != 1 && leapdiff != -1) {
643 pr_err("Cannot schedule %d leap seconds\n", leapdiff);
644 return;
645 }
646
647 if (timediff < 0) {
648 if (stp_clear_leap() < 0)
649 pr_err("failed to clear leap second flags\n");
650 } else if (timediff < 7200) {
651 memset(&txc, 0, sizeof(txc));
652 ret = do_adjtimex(&txc);
653 if (ret < 0)
654 return;
655
656 txc.modes = ADJ_STATUS;
657 if (leapdiff > 0)
658 txc.status |= STA_INS;
659 else
660 txc.status |= STA_DEL;
661 ret = do_adjtimex(&txc);
662 if (ret < 0)
663 pr_err("failed to set leap second flags\n");
664 /* arm Timer to clear leap second flags */
665 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(14400 * MSEC_PER_SEC));
666 } else {
667 /* The day the leap second is scheduled for hasn't been reached. Retry
668 * in one hour.
669 */
670 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(3600 * MSEC_PER_SEC));
671 }
672}
673
674/*
675 * STP work. Check for the STP state and take over the clock
676 * synchronization if the STP clock source is usable.
677 */
678static void stp_work_fn(struct work_struct *work)
679{
680 struct clock_sync_data stp_sync;
681 int rc;
682
683 /* prevent multiple execution. */
684 mutex_lock(&stp_mutex);
685
686 if (!stp_online) {
687 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
688 del_timer_sync(&stp_timer);
689 goto out_unlock;
690 }
691
692 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xf0e0, NULL);
693 if (rc)
694 goto out_unlock;
695
696 rc = __store_stpinfo();
697 if (rc || stp_info.c == 0)
698 goto out_unlock;
699
700 /* Skip synchronization if the clock is already in sync. */
701 if (!check_sync_clock()) {
702 memset(&stp_sync, 0, sizeof(stp_sync));
703 cpus_read_lock();
704 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
705 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
706 cpus_read_unlock();
707 }
708
709 if (!check_sync_clock())
710 /*
711 * There is a usable clock but the synchronization failed.
712 * Retry after a second.
713 */
714 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
715 else if (stp_info.lu)
716 stp_check_leap();
717
718out_unlock:
719 mutex_unlock(&stp_mutex);
720}
721
722/*
723 * STP subsys sysfs interface functions
724 */
725static const struct bus_type stp_subsys = {
726 .name = "stp",
727 .dev_name = "stp",
728};
729
730static ssize_t ctn_id_show(struct device *dev,
731 struct device_attribute *attr,
732 char *buf)
733{
734 ssize_t ret = -ENODATA;
735
736 mutex_lock(&stp_mutex);
737 if (stpinfo_valid())
738 ret = sysfs_emit(buf, "%016lx\n",
739 *(unsigned long *)stp_info.ctnid);
740 mutex_unlock(&stp_mutex);
741 return ret;
742}
743
744static DEVICE_ATTR_RO(ctn_id);
745
746static ssize_t ctn_type_show(struct device *dev,
747 struct device_attribute *attr,
748 char *buf)
749{
750 ssize_t ret = -ENODATA;
751
752 mutex_lock(&stp_mutex);
753 if (stpinfo_valid())
754 ret = sysfs_emit(buf, "%i\n", stp_info.ctn);
755 mutex_unlock(&stp_mutex);
756 return ret;
757}
758
759static DEVICE_ATTR_RO(ctn_type);
760
761static ssize_t dst_offset_show(struct device *dev,
762 struct device_attribute *attr,
763 char *buf)
764{
765 ssize_t ret = -ENODATA;
766
767 mutex_lock(&stp_mutex);
768 if (stpinfo_valid() && (stp_info.vbits & 0x2000))
769 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.dsto);
770 mutex_unlock(&stp_mutex);
771 return ret;
772}
773
774static DEVICE_ATTR_RO(dst_offset);
775
776static ssize_t leap_seconds_show(struct device *dev,
777 struct device_attribute *attr,
778 char *buf)
779{
780 ssize_t ret = -ENODATA;
781
782 mutex_lock(&stp_mutex);
783 if (stpinfo_valid() && (stp_info.vbits & 0x8000))
784 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.leaps);
785 mutex_unlock(&stp_mutex);
786 return ret;
787}
788
789static DEVICE_ATTR_RO(leap_seconds);
790
791static ssize_t leap_seconds_scheduled_show(struct device *dev,
792 struct device_attribute *attr,
793 char *buf)
794{
795 struct stp_stzi stzi;
796 ssize_t ret;
797
798 mutex_lock(&stp_mutex);
799 if (!stpinfo_valid() || !(stp_info.vbits & 0x8000) || !stp_info.lu) {
800 mutex_unlock(&stp_mutex);
801 return -ENODATA;
802 }
803
804 ret = chsc_stzi(stp_page, &stzi, sizeof(stzi));
805 mutex_unlock(&stp_mutex);
806 if (ret < 0)
807 return ret;
808
809 if (!stzi.lsoib.p)
810 return sysfs_emit(buf, "0,0\n");
811
812 return sysfs_emit(buf, "%lu,%d\n",
813 tod_to_ns(stzi.lsoib.nlsout - TOD_UNIX_EPOCH) / NSEC_PER_SEC,
814 stzi.lsoib.nlso - stzi.lsoib.also);
815}
816
817static DEVICE_ATTR_RO(leap_seconds_scheduled);
818
819static ssize_t stratum_show(struct device *dev,
820 struct device_attribute *attr,
821 char *buf)
822{
823 ssize_t ret = -ENODATA;
824
825 mutex_lock(&stp_mutex);
826 if (stpinfo_valid())
827 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.stratum);
828 mutex_unlock(&stp_mutex);
829 return ret;
830}
831
832static DEVICE_ATTR_RO(stratum);
833
834static ssize_t time_offset_show(struct device *dev,
835 struct device_attribute *attr,
836 char *buf)
837{
838 ssize_t ret = -ENODATA;
839
840 mutex_lock(&stp_mutex);
841 if (stpinfo_valid() && (stp_info.vbits & 0x0800))
842 ret = sysfs_emit(buf, "%i\n", (int)stp_info.tto);
843 mutex_unlock(&stp_mutex);
844 return ret;
845}
846
847static DEVICE_ATTR_RO(time_offset);
848
849static ssize_t time_zone_offset_show(struct device *dev,
850 struct device_attribute *attr,
851 char *buf)
852{
853 ssize_t ret = -ENODATA;
854
855 mutex_lock(&stp_mutex);
856 if (stpinfo_valid() && (stp_info.vbits & 0x4000))
857 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.tzo);
858 mutex_unlock(&stp_mutex);
859 return ret;
860}
861
862static DEVICE_ATTR_RO(time_zone_offset);
863
864static ssize_t timing_mode_show(struct device *dev,
865 struct device_attribute *attr,
866 char *buf)
867{
868 ssize_t ret = -ENODATA;
869
870 mutex_lock(&stp_mutex);
871 if (stpinfo_valid())
872 ret = sysfs_emit(buf, "%i\n", stp_info.tmd);
873 mutex_unlock(&stp_mutex);
874 return ret;
875}
876
877static DEVICE_ATTR_RO(timing_mode);
878
879static ssize_t timing_state_show(struct device *dev,
880 struct device_attribute *attr,
881 char *buf)
882{
883 ssize_t ret = -ENODATA;
884
885 mutex_lock(&stp_mutex);
886 if (stpinfo_valid())
887 ret = sysfs_emit(buf, "%i\n", stp_info.tst);
888 mutex_unlock(&stp_mutex);
889 return ret;
890}
891
892static DEVICE_ATTR_RO(timing_state);
893
894static ssize_t online_show(struct device *dev,
895 struct device_attribute *attr,
896 char *buf)
897{
898 return sysfs_emit(buf, "%i\n", stp_online);
899}
900
901static ssize_t online_store(struct device *dev,
902 struct device_attribute *attr,
903 const char *buf, size_t count)
904{
905 unsigned int value;
906
907 value = simple_strtoul(buf, NULL, 0);
908 if (value != 0 && value != 1)
909 return -EINVAL;
910 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
911 return -EOPNOTSUPP;
912 mutex_lock(&stp_mutex);
913 stp_online = value;
914 if (stp_online)
915 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
916 else
917 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
918 queue_work(time_sync_wq, &stp_work);
919 mutex_unlock(&stp_mutex);
920 return count;
921}
922
923/*
924 * Can't use DEVICE_ATTR because the attribute should be named
925 * stp/online but dev_attr_online already exists in this file ..
926 */
927static DEVICE_ATTR_RW(online);
928
929static struct attribute *stp_dev_attrs[] = {
930 &dev_attr_ctn_id.attr,
931 &dev_attr_ctn_type.attr,
932 &dev_attr_dst_offset.attr,
933 &dev_attr_leap_seconds.attr,
934 &dev_attr_online.attr,
935 &dev_attr_leap_seconds_scheduled.attr,
936 &dev_attr_stratum.attr,
937 &dev_attr_time_offset.attr,
938 &dev_attr_time_zone_offset.attr,
939 &dev_attr_timing_mode.attr,
940 &dev_attr_timing_state.attr,
941 NULL
942};
943ATTRIBUTE_GROUPS(stp_dev);
944
945static int __init stp_init_sysfs(void)
946{
947 return subsys_system_register(&stp_subsys, stp_dev_groups);
948}
949
950device_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 <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
105/*
106 * Scheduler clock - returns current time in nanosec units.
107 */
108unsigned long long notrace sched_clock(void)
109{
110 return tod_to_ns(get_tod_clock_monotonic());
111}
112NOKPROBE_SYMBOL(sched_clock);
113
114static void ext_to_timespec64(union tod_clock *clk, struct timespec64 *xt)
115{
116 unsigned long rem, sec, nsec;
117
118 sec = clk->us;
119 rem = do_div(sec, 1000000);
120 nsec = ((clk->sus + (rem << 12)) * 125) >> 9;
121 xt->tv_sec = sec;
122 xt->tv_nsec = nsec;
123}
124
125void clock_comparator_work(void)
126{
127 struct clock_event_device *cd;
128
129 S390_lowcore.clock_comparator = clock_comparator_max;
130 cd = this_cpu_ptr(&comparators);
131 cd->event_handler(cd);
132}
133
134static int s390_next_event(unsigned long delta,
135 struct clock_event_device *evt)
136{
137 S390_lowcore.clock_comparator = get_tod_clock() + delta;
138 set_clock_comparator(S390_lowcore.clock_comparator);
139 return 0;
140}
141
142/*
143 * Set up lowcore and control register of the current cpu to
144 * enable TOD clock and clock comparator interrupts.
145 */
146void init_cpu_timer(void)
147{
148 struct clock_event_device *cd;
149 int cpu;
150
151 S390_lowcore.clock_comparator = clock_comparator_max;
152 set_clock_comparator(S390_lowcore.clock_comparator);
153
154 cpu = smp_processor_id();
155 cd = &per_cpu(comparators, cpu);
156 cd->name = "comparator";
157 cd->features = CLOCK_EVT_FEAT_ONESHOT;
158 cd->mult = 16777;
159 cd->shift = 12;
160 cd->min_delta_ns = 1;
161 cd->min_delta_ticks = 1;
162 cd->max_delta_ns = LONG_MAX;
163 cd->max_delta_ticks = ULONG_MAX;
164 cd->rating = 400;
165 cd->cpumask = cpumask_of(cpu);
166 cd->set_next_event = s390_next_event;
167
168 clockevents_register_device(cd);
169
170 /* Enable clock comparator timer interrupt. */
171 __ctl_set_bit(0,11);
172
173 /* Always allow the timing alert external interrupt. */
174 __ctl_set_bit(0, 4);
175}
176
177static void clock_comparator_interrupt(struct ext_code ext_code,
178 unsigned int param32,
179 unsigned long param64)
180{
181 inc_irq_stat(IRQEXT_CLK);
182 if (S390_lowcore.clock_comparator == clock_comparator_max)
183 set_clock_comparator(S390_lowcore.clock_comparator);
184}
185
186static void stp_timing_alert(struct stp_irq_parm *);
187
188static void timing_alert_interrupt(struct ext_code ext_code,
189 unsigned int param32, unsigned long param64)
190{
191 inc_irq_stat(IRQEXT_TLA);
192 if (param32 & 0x00038000)
193 stp_timing_alert((struct stp_irq_parm *) ¶m32);
194}
195
196static void stp_reset(void);
197
198void read_persistent_clock64(struct timespec64 *ts)
199{
200 union tod_clock clk;
201 u64 delta;
202
203 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
204 store_tod_clock_ext(&clk);
205 clk.eitod -= delta;
206 ext_to_timespec64(&clk, ts);
207}
208
209void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
210 struct timespec64 *boot_offset)
211{
212 struct timespec64 boot_time;
213 union tod_clock clk;
214 u64 delta;
215
216 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
217 clk = tod_clock_base;
218 clk.eitod -= delta;
219 ext_to_timespec64(&clk, &boot_time);
220
221 read_persistent_clock64(wall_time);
222 *boot_offset = timespec64_sub(*wall_time, boot_time);
223}
224
225static u64 read_tod_clock(struct clocksource *cs)
226{
227 unsigned long now, adj;
228
229 preempt_disable(); /* protect from changes to steering parameters */
230 now = get_tod_clock();
231 adj = tod_steering_end - now;
232 if (unlikely((s64) adj > 0))
233 /*
234 * manually steer by 1 cycle every 2^16 cycles. This
235 * corresponds to shifting the tod delta by 15. 1s is
236 * therefore steered in ~9h. The adjust will decrease
237 * over time, until it finally reaches 0.
238 */
239 now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
240 preempt_enable();
241 return now;
242}
243
244static struct clocksource clocksource_tod = {
245 .name = "tod",
246 .rating = 400,
247 .read = read_tod_clock,
248 .mask = CLOCKSOURCE_MASK(64),
249 .mult = 1000,
250 .shift = 12,
251 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
252 .vdso_clock_mode = VDSO_CLOCKMODE_TOD,
253};
254
255struct clocksource * __init clocksource_default_clock(void)
256{
257 return &clocksource_tod;
258}
259
260/*
261 * Initialize the TOD clock and the CPU timer of
262 * the boot cpu.
263 */
264void __init time_init(void)
265{
266 /* Reset time synchronization interfaces. */
267 stp_reset();
268
269 /* request the clock comparator external interrupt */
270 if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
271 panic("Couldn't request external interrupt 0x1004");
272
273 /* request the timing alert external interrupt */
274 if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
275 panic("Couldn't request external interrupt 0x1406");
276
277 if (__clocksource_register(&clocksource_tod) != 0)
278 panic("Could not register TOD clock source");
279
280 /* Enable TOD clock interrupts on the boot cpu. */
281 init_cpu_timer();
282
283 /* Enable cpu timer interrupts on the boot cpu. */
284 vtime_init();
285}
286
287static DEFINE_PER_CPU(atomic_t, clock_sync_word);
288static DEFINE_MUTEX(stp_mutex);
289static unsigned long clock_sync_flags;
290
291#define CLOCK_SYNC_HAS_STP 0
292#define CLOCK_SYNC_STP 1
293#define CLOCK_SYNC_STPINFO_VALID 2
294
295/*
296 * The get_clock function for the physical clock. It will get the current
297 * TOD clock, subtract the LPAR offset and write the result to *clock.
298 * The function returns 0 if the clock is in sync with the external time
299 * source. If the clock mode is local it will return -EOPNOTSUPP and
300 * -EAGAIN if the clock is not in sync with the external reference.
301 */
302int get_phys_clock(unsigned long *clock)
303{
304 atomic_t *sw_ptr;
305 unsigned int sw0, sw1;
306
307 sw_ptr = &get_cpu_var(clock_sync_word);
308 sw0 = atomic_read(sw_ptr);
309 *clock = get_tod_clock() - lpar_offset;
310 sw1 = atomic_read(sw_ptr);
311 put_cpu_var(clock_sync_word);
312 if (sw0 == sw1 && (sw0 & 0x80000000U))
313 /* Success: time is in sync. */
314 return 0;
315 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
316 return -EOPNOTSUPP;
317 if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
318 return -EACCES;
319 return -EAGAIN;
320}
321EXPORT_SYMBOL(get_phys_clock);
322
323/*
324 * Make get_phys_clock() return -EAGAIN.
325 */
326static void disable_sync_clock(void *dummy)
327{
328 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
329 /*
330 * Clear the in-sync bit 2^31. All get_phys_clock calls will
331 * fail until the sync bit is turned back on. In addition
332 * increase the "sequence" counter to avoid the race of an
333 * stp event and the complete recovery against get_phys_clock.
334 */
335 atomic_andnot(0x80000000, sw_ptr);
336 atomic_inc(sw_ptr);
337}
338
339/*
340 * Make get_phys_clock() return 0 again.
341 * Needs to be called from a context disabled for preemption.
342 */
343static void enable_sync_clock(void)
344{
345 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
346 atomic_or(0x80000000, sw_ptr);
347}
348
349/*
350 * Function to check if the clock is in sync.
351 */
352static inline int check_sync_clock(void)
353{
354 atomic_t *sw_ptr;
355 int rc;
356
357 sw_ptr = &get_cpu_var(clock_sync_word);
358 rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
359 put_cpu_var(clock_sync_word);
360 return rc;
361}
362
363/*
364 * Apply clock delta to the global data structures.
365 * This is called once on the CPU that performed the clock sync.
366 */
367static void clock_sync_global(unsigned long delta)
368{
369 unsigned long now, adj;
370 struct ptff_qto qto;
371 int cs;
372
373 /* Fixup the monotonic sched clock. */
374 tod_clock_base.eitod += delta;
375 /* Adjust TOD steering parameters. */
376 now = get_tod_clock();
377 adj = tod_steering_end - now;
378 if (unlikely((s64) adj >= 0))
379 /* Calculate how much of the old adjustment is left. */
380 tod_steering_delta = (tod_steering_delta < 0) ?
381 -(adj >> 15) : (adj >> 15);
382 tod_steering_delta += delta;
383 if ((abs(tod_steering_delta) >> 48) != 0)
384 panic("TOD clock sync offset %li is too large to drift\n",
385 tod_steering_delta);
386 tod_steering_end = now + (abs(tod_steering_delta) << 15);
387 for (cs = 0; cs < CS_BASES; cs++) {
388 vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
389 vdso_data[cs].arch_data.tod_steering_delta = tod_steering_delta;
390 }
391
392 /* Update LPAR offset. */
393 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
394 lpar_offset = qto.tod_epoch_difference;
395 /* Call the TOD clock change notifier. */
396 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0, &delta);
397}
398
399/*
400 * Apply clock delta to the per-CPU data structures of this CPU.
401 * This is called for each online CPU after the call to clock_sync_global.
402 */
403static void clock_sync_local(unsigned long delta)
404{
405 /* Add the delta to the clock comparator. */
406 if (S390_lowcore.clock_comparator != clock_comparator_max) {
407 S390_lowcore.clock_comparator += delta;
408 set_clock_comparator(S390_lowcore.clock_comparator);
409 }
410 /* Adjust the last_update_clock time-stamp. */
411 S390_lowcore.last_update_clock += delta;
412}
413
414/* Single threaded workqueue used for stp sync events */
415static struct workqueue_struct *time_sync_wq;
416
417static void __init time_init_wq(void)
418{
419 if (time_sync_wq)
420 return;
421 time_sync_wq = create_singlethread_workqueue("timesync");
422}
423
424struct clock_sync_data {
425 atomic_t cpus;
426 int in_sync;
427 unsigned long clock_delta;
428};
429
430/*
431 * Server Time Protocol (STP) code.
432 */
433static bool stp_online;
434static struct stp_sstpi stp_info;
435static void *stp_page;
436
437static void stp_work_fn(struct work_struct *work);
438static DECLARE_WORK(stp_work, stp_work_fn);
439static struct timer_list stp_timer;
440
441static int __init early_parse_stp(char *p)
442{
443 return kstrtobool(p, &stp_online);
444}
445early_param("stp", early_parse_stp);
446
447/*
448 * Reset STP attachment.
449 */
450static void __init stp_reset(void)
451{
452 int rc;
453
454 stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
455 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
456 if (rc == 0)
457 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
458 else if (stp_online) {
459 pr_warn("The real or virtual hardware system does not provide an STP interface\n");
460 free_page((unsigned long) stp_page);
461 stp_page = NULL;
462 stp_online = false;
463 }
464}
465
466static void stp_timeout(struct timer_list *unused)
467{
468 queue_work(time_sync_wq, &stp_work);
469}
470
471static int __init stp_init(void)
472{
473 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
474 return 0;
475 timer_setup(&stp_timer, stp_timeout, 0);
476 time_init_wq();
477 if (!stp_online)
478 return 0;
479 queue_work(time_sync_wq, &stp_work);
480 return 0;
481}
482
483arch_initcall(stp_init);
484
485/*
486 * STP timing alert. There are three causes:
487 * 1) timing status change
488 * 2) link availability change
489 * 3) time control parameter change
490 * In all three cases we are only interested in the clock source state.
491 * If a STP clock source is now available use it.
492 */
493static void stp_timing_alert(struct stp_irq_parm *intparm)
494{
495 if (intparm->tsc || intparm->lac || intparm->tcpc)
496 queue_work(time_sync_wq, &stp_work);
497}
498
499/*
500 * STP sync check machine check. This is called when the timing state
501 * changes from the synchronized state to the unsynchronized state.
502 * After a STP sync check the clock is not in sync. The machine check
503 * is broadcasted to all cpus at the same time.
504 */
505int stp_sync_check(void)
506{
507 disable_sync_clock(NULL);
508 return 1;
509}
510
511/*
512 * STP island condition machine check. This is called when an attached
513 * server attempts to communicate over an STP link and the servers
514 * have matching CTN ids and have a valid stratum-1 configuration
515 * but the configurations do not match.
516 */
517int stp_island_check(void)
518{
519 disable_sync_clock(NULL);
520 return 1;
521}
522
523void stp_queue_work(void)
524{
525 queue_work(time_sync_wq, &stp_work);
526}
527
528static int __store_stpinfo(void)
529{
530 int rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
531
532 if (rc)
533 clear_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
534 else
535 set_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
536 return rc;
537}
538
539static int stpinfo_valid(void)
540{
541 return stp_online && test_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
542}
543
544static int stp_sync_clock(void *data)
545{
546 struct clock_sync_data *sync = data;
547 u64 clock_delta, flags;
548 static int first;
549 int rc;
550
551 enable_sync_clock();
552 if (xchg(&first, 1) == 0) {
553 /* Wait until all other cpus entered the sync function. */
554 while (atomic_read(&sync->cpus) != 0)
555 cpu_relax();
556 rc = 0;
557 if (stp_info.todoff[0] || stp_info.todoff[1] ||
558 stp_info.todoff[2] || stp_info.todoff[3] ||
559 stp_info.tmd != 2) {
560 flags = vdso_update_begin();
561 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
562 &clock_delta);
563 if (rc == 0) {
564 sync->clock_delta = clock_delta;
565 clock_sync_global(clock_delta);
566 rc = __store_stpinfo();
567 if (rc == 0 && stp_info.tmd != 2)
568 rc = -EAGAIN;
569 }
570 vdso_update_end(flags);
571 }
572 sync->in_sync = rc ? -EAGAIN : 1;
573 xchg(&first, 0);
574 } else {
575 /* Slave */
576 atomic_dec(&sync->cpus);
577 /* Wait for in_sync to be set. */
578 while (READ_ONCE(sync->in_sync) == 0)
579 __udelay(1);
580 }
581 if (sync->in_sync != 1)
582 /* Didn't work. Clear per-cpu in sync bit again. */
583 disable_sync_clock(NULL);
584 /* Apply clock delta to per-CPU fields of this CPU. */
585 clock_sync_local(sync->clock_delta);
586
587 return 0;
588}
589
590static int stp_clear_leap(void)
591{
592 struct __kernel_timex txc;
593 int ret;
594
595 memset(&txc, 0, sizeof(txc));
596
597 ret = do_adjtimex(&txc);
598 if (ret < 0)
599 return ret;
600
601 txc.modes = ADJ_STATUS;
602 txc.status &= ~(STA_INS|STA_DEL);
603 return do_adjtimex(&txc);
604}
605
606static void stp_check_leap(void)
607{
608 struct stp_stzi stzi;
609 struct stp_lsoib *lsoib = &stzi.lsoib;
610 struct __kernel_timex txc;
611 int64_t timediff;
612 int leapdiff, ret;
613
614 if (!stp_info.lu || !check_sync_clock()) {
615 /*
616 * Either a scheduled leap second was removed by the operator,
617 * or STP is out of sync. In both cases, clear the leap second
618 * kernel flags.
619 */
620 if (stp_clear_leap() < 0)
621 pr_err("failed to clear leap second flags\n");
622 return;
623 }
624
625 if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) {
626 pr_err("stzi failed\n");
627 return;
628 }
629
630 timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC;
631 leapdiff = lsoib->nlso - lsoib->also;
632
633 if (leapdiff != 1 && leapdiff != -1) {
634 pr_err("Cannot schedule %d leap seconds\n", leapdiff);
635 return;
636 }
637
638 if (timediff < 0) {
639 if (stp_clear_leap() < 0)
640 pr_err("failed to clear leap second flags\n");
641 } else if (timediff < 7200) {
642 memset(&txc, 0, sizeof(txc));
643 ret = do_adjtimex(&txc);
644 if (ret < 0)
645 return;
646
647 txc.modes = ADJ_STATUS;
648 if (leapdiff > 0)
649 txc.status |= STA_INS;
650 else
651 txc.status |= STA_DEL;
652 ret = do_adjtimex(&txc);
653 if (ret < 0)
654 pr_err("failed to set leap second flags\n");
655 /* arm Timer to clear leap second flags */
656 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(14400 * MSEC_PER_SEC));
657 } else {
658 /* The day the leap second is scheduled for hasn't been reached. Retry
659 * in one hour.
660 */
661 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(3600 * MSEC_PER_SEC));
662 }
663}
664
665/*
666 * STP work. Check for the STP state and take over the clock
667 * synchronization if the STP clock source is usable.
668 */
669static void stp_work_fn(struct work_struct *work)
670{
671 struct clock_sync_data stp_sync;
672 int rc;
673
674 /* prevent multiple execution. */
675 mutex_lock(&stp_mutex);
676
677 if (!stp_online) {
678 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
679 del_timer_sync(&stp_timer);
680 goto out_unlock;
681 }
682
683 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xf0e0, NULL);
684 if (rc)
685 goto out_unlock;
686
687 rc = __store_stpinfo();
688 if (rc || stp_info.c == 0)
689 goto out_unlock;
690
691 /* Skip synchronization if the clock is already in sync. */
692 if (!check_sync_clock()) {
693 memset(&stp_sync, 0, sizeof(stp_sync));
694 cpus_read_lock();
695 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
696 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
697 cpus_read_unlock();
698 }
699
700 if (!check_sync_clock())
701 /*
702 * There is a usable clock but the synchonization failed.
703 * Retry after a second.
704 */
705 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
706 else if (stp_info.lu)
707 stp_check_leap();
708
709out_unlock:
710 mutex_unlock(&stp_mutex);
711}
712
713/*
714 * STP subsys sysfs interface functions
715 */
716static struct bus_type stp_subsys = {
717 .name = "stp",
718 .dev_name = "stp",
719};
720
721static ssize_t ctn_id_show(struct device *dev,
722 struct device_attribute *attr,
723 char *buf)
724{
725 ssize_t ret = -ENODATA;
726
727 mutex_lock(&stp_mutex);
728 if (stpinfo_valid())
729 ret = sprintf(buf, "%016lx\n",
730 *(unsigned long *) stp_info.ctnid);
731 mutex_unlock(&stp_mutex);
732 return ret;
733}
734
735static DEVICE_ATTR_RO(ctn_id);
736
737static ssize_t ctn_type_show(struct device *dev,
738 struct device_attribute *attr,
739 char *buf)
740{
741 ssize_t ret = -ENODATA;
742
743 mutex_lock(&stp_mutex);
744 if (stpinfo_valid())
745 ret = sprintf(buf, "%i\n", stp_info.ctn);
746 mutex_unlock(&stp_mutex);
747 return ret;
748}
749
750static DEVICE_ATTR_RO(ctn_type);
751
752static ssize_t dst_offset_show(struct device *dev,
753 struct device_attribute *attr,
754 char *buf)
755{
756 ssize_t ret = -ENODATA;
757
758 mutex_lock(&stp_mutex);
759 if (stpinfo_valid() && (stp_info.vbits & 0x2000))
760 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
761 mutex_unlock(&stp_mutex);
762 return ret;
763}
764
765static DEVICE_ATTR_RO(dst_offset);
766
767static ssize_t leap_seconds_show(struct device *dev,
768 struct device_attribute *attr,
769 char *buf)
770{
771 ssize_t ret = -ENODATA;
772
773 mutex_lock(&stp_mutex);
774 if (stpinfo_valid() && (stp_info.vbits & 0x8000))
775 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
776 mutex_unlock(&stp_mutex);
777 return ret;
778}
779
780static DEVICE_ATTR_RO(leap_seconds);
781
782static ssize_t leap_seconds_scheduled_show(struct device *dev,
783 struct device_attribute *attr,
784 char *buf)
785{
786 struct stp_stzi stzi;
787 ssize_t ret;
788
789 mutex_lock(&stp_mutex);
790 if (!stpinfo_valid() || !(stp_info.vbits & 0x8000) || !stp_info.lu) {
791 mutex_unlock(&stp_mutex);
792 return -ENODATA;
793 }
794
795 ret = chsc_stzi(stp_page, &stzi, sizeof(stzi));
796 mutex_unlock(&stp_mutex);
797 if (ret < 0)
798 return ret;
799
800 if (!stzi.lsoib.p)
801 return sprintf(buf, "0,0\n");
802
803 return sprintf(buf, "%lu,%d\n",
804 tod_to_ns(stzi.lsoib.nlsout - TOD_UNIX_EPOCH) / NSEC_PER_SEC,
805 stzi.lsoib.nlso - stzi.lsoib.also);
806}
807
808static DEVICE_ATTR_RO(leap_seconds_scheduled);
809
810static ssize_t stratum_show(struct device *dev,
811 struct device_attribute *attr,
812 char *buf)
813{
814 ssize_t ret = -ENODATA;
815
816 mutex_lock(&stp_mutex);
817 if (stpinfo_valid())
818 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
819 mutex_unlock(&stp_mutex);
820 return ret;
821}
822
823static DEVICE_ATTR_RO(stratum);
824
825static ssize_t time_offset_show(struct device *dev,
826 struct device_attribute *attr,
827 char *buf)
828{
829 ssize_t ret = -ENODATA;
830
831 mutex_lock(&stp_mutex);
832 if (stpinfo_valid() && (stp_info.vbits & 0x0800))
833 ret = sprintf(buf, "%i\n", (int) stp_info.tto);
834 mutex_unlock(&stp_mutex);
835 return ret;
836}
837
838static DEVICE_ATTR_RO(time_offset);
839
840static ssize_t time_zone_offset_show(struct device *dev,
841 struct device_attribute *attr,
842 char *buf)
843{
844 ssize_t ret = -ENODATA;
845
846 mutex_lock(&stp_mutex);
847 if (stpinfo_valid() && (stp_info.vbits & 0x4000))
848 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
849 mutex_unlock(&stp_mutex);
850 return ret;
851}
852
853static DEVICE_ATTR_RO(time_zone_offset);
854
855static ssize_t timing_mode_show(struct device *dev,
856 struct device_attribute *attr,
857 char *buf)
858{
859 ssize_t ret = -ENODATA;
860
861 mutex_lock(&stp_mutex);
862 if (stpinfo_valid())
863 ret = sprintf(buf, "%i\n", stp_info.tmd);
864 mutex_unlock(&stp_mutex);
865 return ret;
866}
867
868static DEVICE_ATTR_RO(timing_mode);
869
870static ssize_t timing_state_show(struct device *dev,
871 struct device_attribute *attr,
872 char *buf)
873{
874 ssize_t ret = -ENODATA;
875
876 mutex_lock(&stp_mutex);
877 if (stpinfo_valid())
878 ret = sprintf(buf, "%i\n", stp_info.tst);
879 mutex_unlock(&stp_mutex);
880 return ret;
881}
882
883static DEVICE_ATTR_RO(timing_state);
884
885static ssize_t online_show(struct device *dev,
886 struct device_attribute *attr,
887 char *buf)
888{
889 return sprintf(buf, "%i\n", stp_online);
890}
891
892static ssize_t online_store(struct device *dev,
893 struct device_attribute *attr,
894 const char *buf, size_t count)
895{
896 unsigned int value;
897
898 value = simple_strtoul(buf, NULL, 0);
899 if (value != 0 && value != 1)
900 return -EINVAL;
901 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
902 return -EOPNOTSUPP;
903 mutex_lock(&stp_mutex);
904 stp_online = value;
905 if (stp_online)
906 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
907 else
908 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
909 queue_work(time_sync_wq, &stp_work);
910 mutex_unlock(&stp_mutex);
911 return count;
912}
913
914/*
915 * Can't use DEVICE_ATTR because the attribute should be named
916 * stp/online but dev_attr_online already exists in this file ..
917 */
918static DEVICE_ATTR_RW(online);
919
920static struct attribute *stp_dev_attrs[] = {
921 &dev_attr_ctn_id.attr,
922 &dev_attr_ctn_type.attr,
923 &dev_attr_dst_offset.attr,
924 &dev_attr_leap_seconds.attr,
925 &dev_attr_online.attr,
926 &dev_attr_leap_seconds_scheduled.attr,
927 &dev_attr_stratum.attr,
928 &dev_attr_time_offset.attr,
929 &dev_attr_time_zone_offset.attr,
930 &dev_attr_timing_mode.attr,
931 &dev_attr_timing_state.attr,
932 NULL
933};
934ATTRIBUTE_GROUPS(stp_dev);
935
936static int __init stp_init_sysfs(void)
937{
938 return subsys_system_register(&stp_subsys, stp_dev_groups);
939}
940
941device_initcall(stp_init_sysfs);