Loading...
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(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(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 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 long 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 || stp_info.tmd != 2) {
558 flags = vdso_update_begin();
559 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
560 &clock_delta);
561 if (rc == 0) {
562 sync->clock_delta = clock_delta;
563 clock_sync_global(clock_delta);
564 rc = __store_stpinfo();
565 if (rc == 0 && stp_info.tmd != 2)
566 rc = -EAGAIN;
567 }
568 vdso_update_end(flags);
569 }
570 sync->in_sync = rc ? -EAGAIN : 1;
571 xchg(&first, 0);
572 } else {
573 /* Slave */
574 atomic_dec(&sync->cpus);
575 /* Wait for in_sync to be set. */
576 while (READ_ONCE(sync->in_sync) == 0)
577 __udelay(1);
578 }
579 if (sync->in_sync != 1)
580 /* Didn't work. Clear per-cpu in sync bit again. */
581 disable_sync_clock(NULL);
582 /* Apply clock delta to per-CPU fields of this CPU. */
583 clock_sync_local(sync->clock_delta);
584
585 return 0;
586}
587
588static int stp_clear_leap(void)
589{
590 struct __kernel_timex txc;
591 int ret;
592
593 memset(&txc, 0, sizeof(txc));
594
595 ret = do_adjtimex(&txc);
596 if (ret < 0)
597 return ret;
598
599 txc.modes = ADJ_STATUS;
600 txc.status &= ~(STA_INS|STA_DEL);
601 return do_adjtimex(&txc);
602}
603
604static void stp_check_leap(void)
605{
606 struct stp_stzi stzi;
607 struct stp_lsoib *lsoib = &stzi.lsoib;
608 struct __kernel_timex txc;
609 int64_t timediff;
610 int leapdiff, ret;
611
612 if (!stp_info.lu || !check_sync_clock()) {
613 /*
614 * Either a scheduled leap second was removed by the operator,
615 * or STP is out of sync. In both cases, clear the leap second
616 * kernel flags.
617 */
618 if (stp_clear_leap() < 0)
619 pr_err("failed to clear leap second flags\n");
620 return;
621 }
622
623 if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) {
624 pr_err("stzi failed\n");
625 return;
626 }
627
628 timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC;
629 leapdiff = lsoib->nlso - lsoib->also;
630
631 if (leapdiff != 1 && leapdiff != -1) {
632 pr_err("Cannot schedule %d leap seconds\n", leapdiff);
633 return;
634 }
635
636 if (timediff < 0) {
637 if (stp_clear_leap() < 0)
638 pr_err("failed to clear leap second flags\n");
639 } else if (timediff < 7200) {
640 memset(&txc, 0, sizeof(txc));
641 ret = do_adjtimex(&txc);
642 if (ret < 0)
643 return;
644
645 txc.modes = ADJ_STATUS;
646 if (leapdiff > 0)
647 txc.status |= STA_INS;
648 else
649 txc.status |= STA_DEL;
650 ret = do_adjtimex(&txc);
651 if (ret < 0)
652 pr_err("failed to set leap second flags\n");
653 /* arm Timer to clear leap second flags */
654 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(14400 * MSEC_PER_SEC));
655 } else {
656 /* The day the leap second is scheduled for hasn't been reached. Retry
657 * in one hour.
658 */
659 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(3600 * MSEC_PER_SEC));
660 }
661}
662
663/*
664 * STP work. Check for the STP state and take over the clock
665 * synchronization if the STP clock source is usable.
666 */
667static void stp_work_fn(struct work_struct *work)
668{
669 struct clock_sync_data stp_sync;
670 int rc;
671
672 /* prevent multiple execution. */
673 mutex_lock(&stp_mutex);
674
675 if (!stp_online) {
676 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
677 del_timer_sync(&stp_timer);
678 goto out_unlock;
679 }
680
681 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xf0e0, NULL);
682 if (rc)
683 goto out_unlock;
684
685 rc = __store_stpinfo();
686 if (rc || stp_info.c == 0)
687 goto out_unlock;
688
689 /* Skip synchronization if the clock is already in sync. */
690 if (!check_sync_clock()) {
691 memset(&stp_sync, 0, sizeof(stp_sync));
692 cpus_read_lock();
693 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
694 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
695 cpus_read_unlock();
696 }
697
698 if (!check_sync_clock())
699 /*
700 * There is a usable clock but the synchonization failed.
701 * Retry after a second.
702 */
703 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
704 else if (stp_info.lu)
705 stp_check_leap();
706
707out_unlock:
708 mutex_unlock(&stp_mutex);
709}
710
711/*
712 * STP subsys sysfs interface functions
713 */
714static struct bus_type stp_subsys = {
715 .name = "stp",
716 .dev_name = "stp",
717};
718
719static ssize_t ctn_id_show(struct device *dev,
720 struct device_attribute *attr,
721 char *buf)
722{
723 ssize_t ret = -ENODATA;
724
725 mutex_lock(&stp_mutex);
726 if (stpinfo_valid())
727 ret = sprintf(buf, "%016lx\n",
728 *(unsigned long *) stp_info.ctnid);
729 mutex_unlock(&stp_mutex);
730 return ret;
731}
732
733static DEVICE_ATTR_RO(ctn_id);
734
735static ssize_t ctn_type_show(struct device *dev,
736 struct device_attribute *attr,
737 char *buf)
738{
739 ssize_t ret = -ENODATA;
740
741 mutex_lock(&stp_mutex);
742 if (stpinfo_valid())
743 ret = sprintf(buf, "%i\n", stp_info.ctn);
744 mutex_unlock(&stp_mutex);
745 return ret;
746}
747
748static DEVICE_ATTR_RO(ctn_type);
749
750static ssize_t dst_offset_show(struct device *dev,
751 struct device_attribute *attr,
752 char *buf)
753{
754 ssize_t ret = -ENODATA;
755
756 mutex_lock(&stp_mutex);
757 if (stpinfo_valid() && (stp_info.vbits & 0x2000))
758 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
759 mutex_unlock(&stp_mutex);
760 return ret;
761}
762
763static DEVICE_ATTR_RO(dst_offset);
764
765static ssize_t leap_seconds_show(struct device *dev,
766 struct device_attribute *attr,
767 char *buf)
768{
769 ssize_t ret = -ENODATA;
770
771 mutex_lock(&stp_mutex);
772 if (stpinfo_valid() && (stp_info.vbits & 0x8000))
773 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
774 mutex_unlock(&stp_mutex);
775 return ret;
776}
777
778static DEVICE_ATTR_RO(leap_seconds);
779
780static ssize_t leap_seconds_scheduled_show(struct device *dev,
781 struct device_attribute *attr,
782 char *buf)
783{
784 struct stp_stzi stzi;
785 ssize_t ret;
786
787 mutex_lock(&stp_mutex);
788 if (!stpinfo_valid() || !(stp_info.vbits & 0x8000) || !stp_info.lu) {
789 mutex_unlock(&stp_mutex);
790 return -ENODATA;
791 }
792
793 ret = chsc_stzi(stp_page, &stzi, sizeof(stzi));
794 mutex_unlock(&stp_mutex);
795 if (ret < 0)
796 return ret;
797
798 if (!stzi.lsoib.p)
799 return sprintf(buf, "0,0\n");
800
801 return sprintf(buf, "%lu,%d\n",
802 tod_to_ns(stzi.lsoib.nlsout - TOD_UNIX_EPOCH) / NSEC_PER_SEC,
803 stzi.lsoib.nlso - stzi.lsoib.also);
804}
805
806static DEVICE_ATTR_RO(leap_seconds_scheduled);
807
808static ssize_t stratum_show(struct device *dev,
809 struct device_attribute *attr,
810 char *buf)
811{
812 ssize_t ret = -ENODATA;
813
814 mutex_lock(&stp_mutex);
815 if (stpinfo_valid())
816 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
817 mutex_unlock(&stp_mutex);
818 return ret;
819}
820
821static DEVICE_ATTR_RO(stratum);
822
823static ssize_t time_offset_show(struct device *dev,
824 struct device_attribute *attr,
825 char *buf)
826{
827 ssize_t ret = -ENODATA;
828
829 mutex_lock(&stp_mutex);
830 if (stpinfo_valid() && (stp_info.vbits & 0x0800))
831 ret = sprintf(buf, "%i\n", (int) stp_info.tto);
832 mutex_unlock(&stp_mutex);
833 return ret;
834}
835
836static DEVICE_ATTR_RO(time_offset);
837
838static ssize_t time_zone_offset_show(struct device *dev,
839 struct device_attribute *attr,
840 char *buf)
841{
842 ssize_t ret = -ENODATA;
843
844 mutex_lock(&stp_mutex);
845 if (stpinfo_valid() && (stp_info.vbits & 0x4000))
846 ret = sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
847 mutex_unlock(&stp_mutex);
848 return ret;
849}
850
851static DEVICE_ATTR_RO(time_zone_offset);
852
853static ssize_t timing_mode_show(struct device *dev,
854 struct device_attribute *attr,
855 char *buf)
856{
857 ssize_t ret = -ENODATA;
858
859 mutex_lock(&stp_mutex);
860 if (stpinfo_valid())
861 ret = sprintf(buf, "%i\n", stp_info.tmd);
862 mutex_unlock(&stp_mutex);
863 return ret;
864}
865
866static DEVICE_ATTR_RO(timing_mode);
867
868static ssize_t timing_state_show(struct device *dev,
869 struct device_attribute *attr,
870 char *buf)
871{
872 ssize_t ret = -ENODATA;
873
874 mutex_lock(&stp_mutex);
875 if (stpinfo_valid())
876 ret = sprintf(buf, "%i\n", stp_info.tst);
877 mutex_unlock(&stp_mutex);
878 return ret;
879}
880
881static DEVICE_ATTR_RO(timing_state);
882
883static ssize_t online_show(struct device *dev,
884 struct device_attribute *attr,
885 char *buf)
886{
887 return sprintf(buf, "%i\n", stp_online);
888}
889
890static ssize_t online_store(struct device *dev,
891 struct device_attribute *attr,
892 const char *buf, size_t count)
893{
894 unsigned int value;
895
896 value = simple_strtoul(buf, NULL, 0);
897 if (value != 0 && value != 1)
898 return -EINVAL;
899 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
900 return -EOPNOTSUPP;
901 mutex_lock(&stp_mutex);
902 stp_online = value;
903 if (stp_online)
904 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
905 else
906 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
907 queue_work(time_sync_wq, &stp_work);
908 mutex_unlock(&stp_mutex);
909 return count;
910}
911
912/*
913 * Can't use DEVICE_ATTR because the attribute should be named
914 * stp/online but dev_attr_online already exists in this file ..
915 */
916static DEVICE_ATTR_RW(online);
917
918static struct attribute *stp_dev_attrs[] = {
919 &dev_attr_ctn_id.attr,
920 &dev_attr_ctn_type.attr,
921 &dev_attr_dst_offset.attr,
922 &dev_attr_leap_seconds.attr,
923 &dev_attr_online.attr,
924 &dev_attr_leap_seconds_scheduled.attr,
925 &dev_attr_stratum.attr,
926 &dev_attr_time_offset.attr,
927 &dev_attr_time_zone_offset.attr,
928 &dev_attr_timing_mode.attr,
929 &dev_attr_timing_state.attr,
930 NULL
931};
932ATTRIBUTE_GROUPS(stp_dev);
933
934static int __init stp_init_sysfs(void)
935{
936 return subsys_system_register(&stp_subsys, stp_dev_groups);
937}
938
939device_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
113static void ext_to_timespec64(unsigned char *clk, struct timespec64 *xt)
114{
115 unsigned long long high, low, rem, sec, nsec;
116
117 /* Split extendnd TOD clock to micro-seconds and sub-micro-seconds */
118 high = (*(unsigned long long *) clk) >> 4;
119 low = (*(unsigned long long *)&clk[7]) << 4;
120 /* Calculate seconds and nano-seconds */
121 sec = high;
122 rem = do_div(sec, 1000000);
123 nsec = (((low >> 32) + (rem << 32)) * 1000) >> 32;
124
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 S390_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 S390_lowcore.clock_comparator = get_tod_clock() + delta;
142 set_clock_comparator(S390_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 S390_lowcore.clock_comparator = clock_comparator_max;
156 set_clock_comparator(S390_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 __ctl_set_bit(0,11);
176
177 /* Always allow the timing alert external interrupt. */
178 __ctl_set_bit(0, 4);
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 (S390_lowcore.clock_comparator == clock_comparator_max)
187 set_clock_comparator(S390_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 unsigned char clk[STORE_CLOCK_EXT_SIZE];
205 __u64 delta;
206
207 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
208 get_tod_clock_ext(clk);
209 *(__u64 *) &clk[1] -= delta;
210 if (*(__u64 *) &clk[1] > delta)
211 clk[0]--;
212 ext_to_timespec64(clk, ts);
213}
214
215void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
216 struct timespec64 *boot_offset)
217{
218 unsigned char clk[STORE_CLOCK_EXT_SIZE];
219 struct timespec64 boot_time;
220 __u64 delta;
221
222 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
223 memcpy(clk, tod_clock_base, STORE_CLOCK_EXT_SIZE);
224 *(__u64 *)&clk[1] -= delta;
225 if (*(__u64 *)&clk[1] > delta)
226 clk[0]--;
227 ext_to_timespec64(clk, &boot_time);
228
229 read_persistent_clock64(wall_time);
230 *boot_offset = timespec64_sub(*wall_time, boot_time);
231}
232
233static u64 read_tod_clock(struct clocksource *cs)
234{
235 unsigned long long now, adj;
236
237 preempt_disable(); /* protect from changes to steering parameters */
238 now = get_tod_clock();
239 adj = tod_steering_end - now;
240 if (unlikely((s64) adj > 0))
241 /*
242 * manually steer by 1 cycle every 2^16 cycles. This
243 * corresponds to shifting the tod delta by 15. 1s is
244 * therefore steered in ~9h. The adjust will decrease
245 * over time, until it finally reaches 0.
246 */
247 now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
248 preempt_enable();
249 return now;
250}
251
252static struct clocksource clocksource_tod = {
253 .name = "tod",
254 .rating = 400,
255 .read = read_tod_clock,
256 .mask = CLOCKSOURCE_MASK(64),
257 .mult = 1000,
258 .shift = 12,
259 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
260};
261
262struct clocksource * __init clocksource_default_clock(void)
263{
264 return &clocksource_tod;
265}
266
267void update_vsyscall(struct timekeeper *tk)
268{
269 u64 nsecps;
270
271 if (tk->tkr_mono.clock != &clocksource_tod)
272 return;
273
274 /* Make userspace gettimeofday spin until we're done. */
275 ++vdso_data->tb_update_count;
276 smp_wmb();
277 vdso_data->xtime_tod_stamp = tk->tkr_mono.cycle_last;
278 vdso_data->xtime_clock_sec = tk->xtime_sec;
279 vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
280 vdso_data->wtom_clock_sec =
281 tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
282 vdso_data->wtom_clock_nsec = tk->tkr_mono.xtime_nsec +
283 + ((u64) tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
284 nsecps = (u64) NSEC_PER_SEC << tk->tkr_mono.shift;
285 while (vdso_data->wtom_clock_nsec >= nsecps) {
286 vdso_data->wtom_clock_nsec -= nsecps;
287 vdso_data->wtom_clock_sec++;
288 }
289
290 vdso_data->xtime_coarse_sec = tk->xtime_sec;
291 vdso_data->xtime_coarse_nsec =
292 (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
293 vdso_data->wtom_coarse_sec =
294 vdso_data->xtime_coarse_sec + tk->wall_to_monotonic.tv_sec;
295 vdso_data->wtom_coarse_nsec =
296 vdso_data->xtime_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
297 while (vdso_data->wtom_coarse_nsec >= NSEC_PER_SEC) {
298 vdso_data->wtom_coarse_nsec -= NSEC_PER_SEC;
299 vdso_data->wtom_coarse_sec++;
300 }
301
302 vdso_data->tk_mult = tk->tkr_mono.mult;
303 vdso_data->tk_shift = tk->tkr_mono.shift;
304 vdso_data->hrtimer_res = hrtimer_resolution;
305 smp_wmb();
306 ++vdso_data->tb_update_count;
307}
308
309extern struct timezone sys_tz;
310
311void update_vsyscall_tz(void)
312{
313 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
314 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
315}
316
317/*
318 * Initialize the TOD clock and the CPU timer of
319 * the boot cpu.
320 */
321void __init time_init(void)
322{
323 /* Reset time synchronization interfaces. */
324 stp_reset();
325
326 /* request the clock comparator external interrupt */
327 if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
328 panic("Couldn't request external interrupt 0x1004");
329
330 /* request the timing alert external interrupt */
331 if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
332 panic("Couldn't request external interrupt 0x1406");
333
334 if (__clocksource_register(&clocksource_tod) != 0)
335 panic("Could not register TOD clock source");
336
337 /* Enable TOD clock interrupts on the boot cpu. */
338 init_cpu_timer();
339
340 /* Enable cpu timer interrupts on the boot cpu. */
341 vtime_init();
342}
343
344static DEFINE_PER_CPU(atomic_t, clock_sync_word);
345static DEFINE_MUTEX(clock_sync_mutex);
346static unsigned long clock_sync_flags;
347
348#define CLOCK_SYNC_HAS_STP 0
349#define CLOCK_SYNC_STP 1
350
351/*
352 * The get_clock function for the physical clock. It will get the current
353 * TOD clock, subtract the LPAR offset and write the result to *clock.
354 * The function returns 0 if the clock is in sync with the external time
355 * source. If the clock mode is local it will return -EOPNOTSUPP and
356 * -EAGAIN if the clock is not in sync with the external reference.
357 */
358int get_phys_clock(unsigned long *clock)
359{
360 atomic_t *sw_ptr;
361 unsigned int sw0, sw1;
362
363 sw_ptr = &get_cpu_var(clock_sync_word);
364 sw0 = atomic_read(sw_ptr);
365 *clock = get_tod_clock() - lpar_offset;
366 sw1 = atomic_read(sw_ptr);
367 put_cpu_var(clock_sync_word);
368 if (sw0 == sw1 && (sw0 & 0x80000000U))
369 /* Success: time is in sync. */
370 return 0;
371 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
372 return -EOPNOTSUPP;
373 if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
374 return -EACCES;
375 return -EAGAIN;
376}
377EXPORT_SYMBOL(get_phys_clock);
378
379/*
380 * Make get_phys_clock() return -EAGAIN.
381 */
382static void disable_sync_clock(void *dummy)
383{
384 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
385 /*
386 * Clear the in-sync bit 2^31. All get_phys_clock calls will
387 * fail until the sync bit is turned back on. In addition
388 * increase the "sequence" counter to avoid the race of an
389 * stp event and the complete recovery against get_phys_clock.
390 */
391 atomic_andnot(0x80000000, sw_ptr);
392 atomic_inc(sw_ptr);
393}
394
395/*
396 * Make get_phys_clock() return 0 again.
397 * Needs to be called from a context disabled for preemption.
398 */
399static void enable_sync_clock(void)
400{
401 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
402 atomic_or(0x80000000, sw_ptr);
403}
404
405/*
406 * Function to check if the clock is in sync.
407 */
408static inline int check_sync_clock(void)
409{
410 atomic_t *sw_ptr;
411 int rc;
412
413 sw_ptr = &get_cpu_var(clock_sync_word);
414 rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
415 put_cpu_var(clock_sync_word);
416 return rc;
417}
418
419/*
420 * Apply clock delta to the global data structures.
421 * This is called once on the CPU that performed the clock sync.
422 */
423static void clock_sync_global(unsigned long long delta)
424{
425 unsigned long now, adj;
426 struct ptff_qto qto;
427
428 /* Fixup the monotonic sched clock. */
429 *(unsigned long long *) &tod_clock_base[1] += delta;
430 if (*(unsigned long long *) &tod_clock_base[1] < delta)
431 /* Epoch overflow */
432 tod_clock_base[0]++;
433 /* Adjust TOD steering parameters. */
434 vdso_data->tb_update_count++;
435 now = get_tod_clock();
436 adj = tod_steering_end - now;
437 if (unlikely((s64) adj >= 0))
438 /* Calculate how much of the old adjustment is left. */
439 tod_steering_delta = (tod_steering_delta < 0) ?
440 -(adj >> 15) : (adj >> 15);
441 tod_steering_delta += delta;
442 if ((abs(tod_steering_delta) >> 48) != 0)
443 panic("TOD clock sync offset %lli is too large to drift\n",
444 tod_steering_delta);
445 tod_steering_end = now + (abs(tod_steering_delta) << 15);
446 vdso_data->ts_dir = (tod_steering_delta < 0) ? 0 : 1;
447 vdso_data->ts_end = tod_steering_end;
448 vdso_data->tb_update_count++;
449 /* Update LPAR offset. */
450 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
451 lpar_offset = qto.tod_epoch_difference;
452 /* Call the TOD clock change notifier. */
453 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0, &delta);
454}
455
456/*
457 * Apply clock delta to the per-CPU data structures of this CPU.
458 * This is called for each online CPU after the call to clock_sync_global.
459 */
460static void clock_sync_local(unsigned long long delta)
461{
462 /* Add the delta to the clock comparator. */
463 if (S390_lowcore.clock_comparator != clock_comparator_max) {
464 S390_lowcore.clock_comparator += delta;
465 set_clock_comparator(S390_lowcore.clock_comparator);
466 }
467 /* Adjust the last_update_clock time-stamp. */
468 S390_lowcore.last_update_clock += delta;
469}
470
471/* Single threaded workqueue used for stp sync events */
472static struct workqueue_struct *time_sync_wq;
473
474static void __init time_init_wq(void)
475{
476 if (time_sync_wq)
477 return;
478 time_sync_wq = create_singlethread_workqueue("timesync");
479}
480
481struct clock_sync_data {
482 atomic_t cpus;
483 int in_sync;
484 unsigned long long clock_delta;
485};
486
487/*
488 * Server Time Protocol (STP) code.
489 */
490static bool stp_online;
491static struct stp_sstpi stp_info;
492static void *stp_page;
493
494static void stp_work_fn(struct work_struct *work);
495static DEFINE_MUTEX(stp_work_mutex);
496static DECLARE_WORK(stp_work, stp_work_fn);
497static struct timer_list stp_timer;
498
499static int __init early_parse_stp(char *p)
500{
501 return kstrtobool(p, &stp_online);
502}
503early_param("stp", early_parse_stp);
504
505/*
506 * Reset STP attachment.
507 */
508static void __init stp_reset(void)
509{
510 int rc;
511
512 stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
513 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
514 if (rc == 0)
515 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
516 else if (stp_online) {
517 pr_warn("The real or virtual hardware system does not provide an STP interface\n");
518 free_page((unsigned long) stp_page);
519 stp_page = NULL;
520 stp_online = false;
521 }
522}
523
524static void stp_timeout(struct timer_list *unused)
525{
526 queue_work(time_sync_wq, &stp_work);
527}
528
529static int __init stp_init(void)
530{
531 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
532 return 0;
533 timer_setup(&stp_timer, stp_timeout, 0);
534 time_init_wq();
535 if (!stp_online)
536 return 0;
537 queue_work(time_sync_wq, &stp_work);
538 return 0;
539}
540
541arch_initcall(stp_init);
542
543/*
544 * STP timing alert. There are three causes:
545 * 1) timing status change
546 * 2) link availability change
547 * 3) time control parameter change
548 * In all three cases we are only interested in the clock source state.
549 * If a STP clock source is now available use it.
550 */
551static void stp_timing_alert(struct stp_irq_parm *intparm)
552{
553 if (intparm->tsc || intparm->lac || intparm->tcpc)
554 queue_work(time_sync_wq, &stp_work);
555}
556
557/*
558 * STP sync check machine check. This is called when the timing state
559 * changes from the synchronized state to the unsynchronized state.
560 * After a STP sync check the clock is not in sync. The machine check
561 * is broadcasted to all cpus at the same time.
562 */
563int stp_sync_check(void)
564{
565 disable_sync_clock(NULL);
566 return 1;
567}
568
569/*
570 * STP island condition machine check. This is called when an attached
571 * server attempts to communicate over an STP link and the servers
572 * have matching CTN ids and have a valid stratum-1 configuration
573 * but the configurations do not match.
574 */
575int stp_island_check(void)
576{
577 disable_sync_clock(NULL);
578 return 1;
579}
580
581void stp_queue_work(void)
582{
583 queue_work(time_sync_wq, &stp_work);
584}
585
586static int stp_sync_clock(void *data)
587{
588 struct clock_sync_data *sync = data;
589 unsigned long long clock_delta;
590 static int first;
591 int rc;
592
593 enable_sync_clock();
594 if (xchg(&first, 1) == 0) {
595 /* Wait until all other cpus entered the sync function. */
596 while (atomic_read(&sync->cpus) != 0)
597 cpu_relax();
598 rc = 0;
599 if (stp_info.todoff[0] || stp_info.todoff[1] ||
600 stp_info.todoff[2] || stp_info.todoff[3] ||
601 stp_info.tmd != 2) {
602 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
603 &clock_delta);
604 if (rc == 0) {
605 sync->clock_delta = clock_delta;
606 clock_sync_global(clock_delta);
607 rc = chsc_sstpi(stp_page, &stp_info,
608 sizeof(struct stp_sstpi));
609 if (rc == 0 && stp_info.tmd != 2)
610 rc = -EAGAIN;
611 }
612 }
613 sync->in_sync = rc ? -EAGAIN : 1;
614 xchg(&first, 0);
615 } else {
616 /* Slave */
617 atomic_dec(&sync->cpus);
618 /* Wait for in_sync to be set. */
619 while (READ_ONCE(sync->in_sync) == 0)
620 __udelay(1);
621 }
622 if (sync->in_sync != 1)
623 /* Didn't work. Clear per-cpu in sync bit again. */
624 disable_sync_clock(NULL);
625 /* Apply clock delta to per-CPU fields of this CPU. */
626 clock_sync_local(sync->clock_delta);
627
628 return 0;
629}
630
631/*
632 * STP work. Check for the STP state and take over the clock
633 * synchronization if the STP clock source is usable.
634 */
635static void stp_work_fn(struct work_struct *work)
636{
637 struct clock_sync_data stp_sync;
638 int rc;
639
640 /* prevent multiple execution. */
641 mutex_lock(&stp_work_mutex);
642
643 if (!stp_online) {
644 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
645 del_timer_sync(&stp_timer);
646 goto out_unlock;
647 }
648
649 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0, NULL);
650 if (rc)
651 goto out_unlock;
652
653 rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
654 if (rc || stp_info.c == 0)
655 goto out_unlock;
656
657 /* Skip synchronization if the clock is already in sync. */
658 if (check_sync_clock())
659 goto out_unlock;
660
661 memset(&stp_sync, 0, sizeof(stp_sync));
662 cpus_read_lock();
663 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
664 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
665 cpus_read_unlock();
666
667 if (!check_sync_clock())
668 /*
669 * There is a usable clock but the synchonization failed.
670 * Retry after a second.
671 */
672 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
673
674out_unlock:
675 mutex_unlock(&stp_work_mutex);
676}
677
678/*
679 * STP subsys sysfs interface functions
680 */
681static struct bus_type stp_subsys = {
682 .name = "stp",
683 .dev_name = "stp",
684};
685
686static ssize_t ctn_id_show(struct device *dev,
687 struct device_attribute *attr,
688 char *buf)
689{
690 if (!stp_online)
691 return -ENODATA;
692 return sprintf(buf, "%016llx\n",
693 *(unsigned long long *) stp_info.ctnid);
694}
695
696static DEVICE_ATTR_RO(ctn_id);
697
698static ssize_t ctn_type_show(struct device *dev,
699 struct device_attribute *attr,
700 char *buf)
701{
702 if (!stp_online)
703 return -ENODATA;
704 return sprintf(buf, "%i\n", stp_info.ctn);
705}
706
707static DEVICE_ATTR_RO(ctn_type);
708
709static ssize_t dst_offset_show(struct device *dev,
710 struct device_attribute *attr,
711 char *buf)
712{
713 if (!stp_online || !(stp_info.vbits & 0x2000))
714 return -ENODATA;
715 return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
716}
717
718static DEVICE_ATTR_RO(dst_offset);
719
720static ssize_t leap_seconds_show(struct device *dev,
721 struct device_attribute *attr,
722 char *buf)
723{
724 if (!stp_online || !(stp_info.vbits & 0x8000))
725 return -ENODATA;
726 return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
727}
728
729static DEVICE_ATTR_RO(leap_seconds);
730
731static ssize_t stratum_show(struct device *dev,
732 struct device_attribute *attr,
733 char *buf)
734{
735 if (!stp_online)
736 return -ENODATA;
737 return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
738}
739
740static DEVICE_ATTR_RO(stratum);
741
742static ssize_t time_offset_show(struct device *dev,
743 struct device_attribute *attr,
744 char *buf)
745{
746 if (!stp_online || !(stp_info.vbits & 0x0800))
747 return -ENODATA;
748 return sprintf(buf, "%i\n", (int) stp_info.tto);
749}
750
751static DEVICE_ATTR_RO(time_offset);
752
753static ssize_t time_zone_offset_show(struct device *dev,
754 struct device_attribute *attr,
755 char *buf)
756{
757 if (!stp_online || !(stp_info.vbits & 0x4000))
758 return -ENODATA;
759 return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
760}
761
762static DEVICE_ATTR_RO(time_zone_offset);
763
764static ssize_t timing_mode_show(struct device *dev,
765 struct device_attribute *attr,
766 char *buf)
767{
768 if (!stp_online)
769 return -ENODATA;
770 return sprintf(buf, "%i\n", stp_info.tmd);
771}
772
773static DEVICE_ATTR_RO(timing_mode);
774
775static ssize_t timing_state_show(struct device *dev,
776 struct device_attribute *attr,
777 char *buf)
778{
779 if (!stp_online)
780 return -ENODATA;
781 return sprintf(buf, "%i\n", stp_info.tst);
782}
783
784static DEVICE_ATTR_RO(timing_state);
785
786static ssize_t online_show(struct device *dev,
787 struct device_attribute *attr,
788 char *buf)
789{
790 return sprintf(buf, "%i\n", stp_online);
791}
792
793static ssize_t online_store(struct device *dev,
794 struct device_attribute *attr,
795 const char *buf, size_t count)
796{
797 unsigned int value;
798
799 value = simple_strtoul(buf, NULL, 0);
800 if (value != 0 && value != 1)
801 return -EINVAL;
802 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
803 return -EOPNOTSUPP;
804 mutex_lock(&clock_sync_mutex);
805 stp_online = value;
806 if (stp_online)
807 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
808 else
809 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
810 queue_work(time_sync_wq, &stp_work);
811 mutex_unlock(&clock_sync_mutex);
812 return count;
813}
814
815/*
816 * Can't use DEVICE_ATTR because the attribute should be named
817 * stp/online but dev_attr_online already exists in this file ..
818 */
819static DEVICE_ATTR_RW(online);
820
821static struct device_attribute *stp_attributes[] = {
822 &dev_attr_ctn_id,
823 &dev_attr_ctn_type,
824 &dev_attr_dst_offset,
825 &dev_attr_leap_seconds,
826 &dev_attr_online,
827 &dev_attr_stratum,
828 &dev_attr_time_offset,
829 &dev_attr_time_zone_offset,
830 &dev_attr_timing_mode,
831 &dev_attr_timing_state,
832 NULL
833};
834
835static int __init stp_init_sysfs(void)
836{
837 struct device_attribute **attr;
838 int rc;
839
840 rc = subsys_system_register(&stp_subsys, NULL);
841 if (rc)
842 goto out;
843 for (attr = stp_attributes; *attr; attr++) {
844 rc = device_create_file(stp_subsys.dev_root, *attr);
845 if (rc)
846 goto out_unreg;
847 }
848 return 0;
849out_unreg:
850 for (; attr >= stp_attributes; attr--)
851 device_remove_file(stp_subsys.dev_root, *attr);
852 bus_unregister(&stp_subsys);
853out:
854 return rc;
855}
856
857device_initcall(stp_init_sysfs);