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 | |
58 | union tod_clock tod_clock_base __section(".data" ); |
59 | EXPORT_SYMBOL_GPL(tod_clock_base); |
60 | |
61 | u64 clock_comparator_max = -1ULL; |
62 | EXPORT_SYMBOL_GPL(clock_comparator_max); |
63 | |
64 | static DEFINE_PER_CPU(struct clock_event_device, comparators); |
65 | |
66 | ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier); |
67 | EXPORT_SYMBOL(s390_epoch_delta_notifier); |
68 | |
69 | unsigned char ptff_function_mask[16]; |
70 | |
71 | static unsigned long lpar_offset; |
72 | static unsigned long initial_leap_seconds; |
73 | static unsigned long tod_steering_end; |
74 | static long tod_steering_delta; |
75 | |
76 | /* |
77 | * Get time offsets with PTFF |
78 | */ |
79 | void __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 | unsigned long long noinstr sched_clock_noinstr(void) |
106 | { |
107 | return tod_to_ns(__get_tod_clock_monotonic()); |
108 | } |
109 | |
110 | /* |
111 | * Scheduler clock - returns current time in nanosec units. |
112 | */ |
113 | unsigned long long notrace sched_clock(void) |
114 | { |
115 | return tod_to_ns(get_tod_clock_monotonic()); |
116 | } |
117 | NOKPROBE_SYMBOL(sched_clock); |
118 | |
119 | static void ext_to_timespec64(union tod_clock *clk, struct timespec64 *xt) |
120 | { |
121 | unsigned long rem, sec, nsec; |
122 | |
123 | sec = clk->us; |
124 | rem = do_div(sec, 1000000); |
125 | nsec = ((clk->sus + (rem << 12)) * 125) >> 9; |
126 | xt->tv_sec = sec; |
127 | xt->tv_nsec = nsec; |
128 | } |
129 | |
130 | void clock_comparator_work(void) |
131 | { |
132 | struct clock_event_device *cd; |
133 | |
134 | S390_lowcore.clock_comparator = clock_comparator_max; |
135 | cd = this_cpu_ptr(&comparators); |
136 | cd->event_handler(cd); |
137 | } |
138 | |
139 | static int s390_next_event(unsigned long delta, |
140 | struct clock_event_device *evt) |
141 | { |
142 | S390_lowcore.clock_comparator = get_tod_clock() + delta; |
143 | set_clock_comparator(S390_lowcore.clock_comparator); |
144 | return 0; |
145 | } |
146 | |
147 | /* |
148 | * Set up lowcore and control register of the current cpu to |
149 | * enable TOD clock and clock comparator interrupts. |
150 | */ |
151 | void init_cpu_timer(void) |
152 | { |
153 | struct clock_event_device *cd; |
154 | int cpu; |
155 | |
156 | S390_lowcore.clock_comparator = clock_comparator_max; |
157 | set_clock_comparator(S390_lowcore.clock_comparator); |
158 | |
159 | cpu = smp_processor_id(); |
160 | cd = &per_cpu(comparators, cpu); |
161 | cd->name = "comparator" ; |
162 | cd->features = CLOCK_EVT_FEAT_ONESHOT; |
163 | cd->mult = 16777; |
164 | cd->shift = 12; |
165 | cd->min_delta_ns = 1; |
166 | cd->min_delta_ticks = 1; |
167 | cd->max_delta_ns = LONG_MAX; |
168 | cd->max_delta_ticks = ULONG_MAX; |
169 | cd->rating = 400; |
170 | cd->cpumask = cpumask_of(cpu); |
171 | cd->set_next_event = s390_next_event; |
172 | |
173 | clockevents_register_device(dev: cd); |
174 | |
175 | /* Enable clock comparator timer interrupt. */ |
176 | local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SUBMASK_BIT); |
177 | |
178 | /* Always allow the timing alert external interrupt. */ |
179 | local_ctl_set_bit(0, CR0_ETR_SUBMASK_BIT); |
180 | } |
181 | |
182 | static void clock_comparator_interrupt(struct ext_code ext_code, |
183 | unsigned int param32, |
184 | unsigned long param64) |
185 | { |
186 | inc_irq_stat(IRQEXT_CLK); |
187 | if (S390_lowcore.clock_comparator == clock_comparator_max) |
188 | set_clock_comparator(S390_lowcore.clock_comparator); |
189 | } |
190 | |
191 | static void stp_timing_alert(struct stp_irq_parm *); |
192 | |
193 | static void timing_alert_interrupt(struct ext_code ext_code, |
194 | unsigned int param32, unsigned long param64) |
195 | { |
196 | inc_irq_stat(IRQEXT_TLA); |
197 | if (param32 & 0x00038000) |
198 | stp_timing_alert((struct stp_irq_parm *) ¶m32); |
199 | } |
200 | |
201 | static void stp_reset(void); |
202 | |
203 | void read_persistent_clock64(struct timespec64 *ts) |
204 | { |
205 | union tod_clock clk; |
206 | u64 delta; |
207 | |
208 | delta = initial_leap_seconds + TOD_UNIX_EPOCH; |
209 | store_tod_clock_ext(&clk); |
210 | clk.eitod -= delta; |
211 | ext_to_timespec64(clk: &clk, xt: ts); |
212 | } |
213 | |
214 | void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time, |
215 | struct timespec64 *boot_offset) |
216 | { |
217 | struct timespec64 boot_time; |
218 | union tod_clock clk; |
219 | u64 delta; |
220 | |
221 | delta = initial_leap_seconds + TOD_UNIX_EPOCH; |
222 | clk = tod_clock_base; |
223 | clk.eitod -= delta; |
224 | ext_to_timespec64(clk: &clk, xt: &boot_time); |
225 | |
226 | read_persistent_clock64(ts: wall_time); |
227 | *boot_offset = timespec64_sub(lhs: *wall_time, rhs: boot_time); |
228 | } |
229 | |
230 | static u64 read_tod_clock(struct clocksource *cs) |
231 | { |
232 | unsigned long now, adj; |
233 | |
234 | preempt_disable(); /* protect from changes to steering parameters */ |
235 | now = get_tod_clock(); |
236 | adj = tod_steering_end - now; |
237 | if (unlikely((s64) adj > 0)) |
238 | /* |
239 | * manually steer by 1 cycle every 2^16 cycles. This |
240 | * corresponds to shifting the tod delta by 15. 1s is |
241 | * therefore steered in ~9h. The adjust will decrease |
242 | * over time, until it finally reaches 0. |
243 | */ |
244 | now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15); |
245 | preempt_enable(); |
246 | return now; |
247 | } |
248 | |
249 | static struct clocksource clocksource_tod = { |
250 | .name = "tod" , |
251 | .rating = 400, |
252 | .read = read_tod_clock, |
253 | .mask = CLOCKSOURCE_MASK(64), |
254 | .mult = 4096000, |
255 | .shift = 24, |
256 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
257 | .vdso_clock_mode = VDSO_CLOCKMODE_TOD, |
258 | }; |
259 | |
260 | struct 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 | */ |
269 | void __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(fmt: "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(fmt: "Couldn't request external interrupt 0x1406" ); |
281 | |
282 | if (__clocksource_register(cs: &clocksource_tod) != 0) |
283 | panic(fmt: "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 | |
292 | static DEFINE_PER_CPU(atomic_t, clock_sync_word); |
293 | static DEFINE_MUTEX(stp_mutex); |
294 | static 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 | */ |
307 | int 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(v: sw_ptr); |
314 | *clock = get_tod_clock() - lpar_offset; |
315 | sw1 = atomic_read(v: 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 | } |
326 | EXPORT_SYMBOL(get_phys_clock); |
327 | |
328 | /* |
329 | * Make get_phys_clock() return -EAGAIN. |
330 | */ |
331 | static 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(i: 0x80000000, v: sw_ptr); |
341 | atomic_inc(v: 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 | */ |
348 | static void enable_sync_clock(void) |
349 | { |
350 | atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word); |
351 | atomic_or(i: 0x80000000, v: sw_ptr); |
352 | } |
353 | |
354 | /* |
355 | * Function to check if the clock is in sync. |
356 | */ |
357 | static 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(v: 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 | */ |
372 | static 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(fmt: "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(nh: &s390_epoch_delta_notifier, val: 0, v: &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 | */ |
408 | static void clock_sync_local(long delta) |
409 | { |
410 | /* Add the delta to the clock comparator. */ |
411 | if (S390_lowcore.clock_comparator != clock_comparator_max) { |
412 | S390_lowcore.clock_comparator += delta; |
413 | set_clock_comparator(S390_lowcore.clock_comparator); |
414 | } |
415 | /* Adjust the last_update_clock time-stamp. */ |
416 | S390_lowcore.last_update_clock += delta; |
417 | } |
418 | |
419 | /* Single threaded workqueue used for stp sync events */ |
420 | static struct workqueue_struct *time_sync_wq; |
421 | |
422 | static void __init time_init_wq(void) |
423 | { |
424 | if (time_sync_wq) |
425 | return; |
426 | time_sync_wq = create_singlethread_workqueue("timesync" ); |
427 | } |
428 | |
429 | struct 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 | */ |
438 | static bool stp_online; |
439 | static struct stp_sstpi stp_info; |
440 | static void *stp_page; |
441 | |
442 | static void stp_work_fn(struct work_struct *work); |
443 | static DECLARE_WORK(stp_work, stp_work_fn); |
444 | static struct timer_list stp_timer; |
445 | |
446 | static int __init early_parse_stp(char *p) |
447 | { |
448 | return kstrtobool(s: p, res: &stp_online); |
449 | } |
450 | early_param("stp" , early_parse_stp); |
451 | |
452 | /* |
453 | * Reset STP attachment. |
454 | */ |
455 | static 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, addr: &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 | |
471 | static void stp_timeout(struct timer_list *unused) |
472 | { |
473 | queue_work(wq: time_sync_wq, work: &stp_work); |
474 | } |
475 | |
476 | static int __init stp_init(void) |
477 | { |
478 | if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags)) |
479 | return 0; |
480 | timer_setup(&stp_timer, stp_timeout, 0); |
481 | time_init_wq(); |
482 | if (!stp_online) |
483 | return 0; |
484 | queue_work(wq: time_sync_wq, work: &stp_work); |
485 | return 0; |
486 | } |
487 | |
488 | arch_initcall(stp_init); |
489 | |
490 | /* |
491 | * STP timing alert. There are three causes: |
492 | * 1) timing status change |
493 | * 2) link availability change |
494 | * 3) time control parameter change |
495 | * In all three cases we are only interested in the clock source state. |
496 | * If a STP clock source is now available use it. |
497 | */ |
498 | static void stp_timing_alert(struct stp_irq_parm *intparm) |
499 | { |
500 | if (intparm->tsc || intparm->lac || intparm->tcpc) |
501 | queue_work(wq: time_sync_wq, work: &stp_work); |
502 | } |
503 | |
504 | /* |
505 | * STP sync check machine check. This is called when the timing state |
506 | * changes from the synchronized state to the unsynchronized state. |
507 | * After a STP sync check the clock is not in sync. The machine check |
508 | * is broadcasted to all cpus at the same time. |
509 | */ |
510 | int stp_sync_check(void) |
511 | { |
512 | disable_sync_clock(NULL); |
513 | return 1; |
514 | } |
515 | |
516 | /* |
517 | * STP island condition machine check. This is called when an attached |
518 | * server attempts to communicate over an STP link and the servers |
519 | * have matching CTN ids and have a valid stratum-1 configuration |
520 | * but the configurations do not match. |
521 | */ |
522 | int stp_island_check(void) |
523 | { |
524 | disable_sync_clock(NULL); |
525 | return 1; |
526 | } |
527 | |
528 | void stp_queue_work(void) |
529 | { |
530 | queue_work(wq: time_sync_wq, work: &stp_work); |
531 | } |
532 | |
533 | static int __store_stpinfo(void) |
534 | { |
535 | int rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi)); |
536 | |
537 | if (rc) |
538 | clear_bit(CLOCK_SYNC_STPINFO_VALID, addr: &clock_sync_flags); |
539 | else |
540 | set_bit(CLOCK_SYNC_STPINFO_VALID, addr: &clock_sync_flags); |
541 | return rc; |
542 | } |
543 | |
544 | static int stpinfo_valid(void) |
545 | { |
546 | return stp_online && test_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags); |
547 | } |
548 | |
549 | static int stp_sync_clock(void *data) |
550 | { |
551 | struct clock_sync_data *sync = data; |
552 | long clock_delta, flags; |
553 | static int first; |
554 | int rc; |
555 | |
556 | enable_sync_clock(); |
557 | if (xchg(&first, 1) == 0) { |
558 | /* Wait until all other cpus entered the sync function. */ |
559 | while (atomic_read(v: &sync->cpus) != 0) |
560 | cpu_relax(); |
561 | rc = 0; |
562 | if (stp_info.todoff || stp_info.tmd != 2) { |
563 | flags = vdso_update_begin(); |
564 | rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0, |
565 | &clock_delta); |
566 | if (rc == 0) { |
567 | sync->clock_delta = clock_delta; |
568 | clock_sync_global(delta: clock_delta); |
569 | rc = __store_stpinfo(); |
570 | if (rc == 0 && stp_info.tmd != 2) |
571 | rc = -EAGAIN; |
572 | } |
573 | vdso_update_end(flags); |
574 | } |
575 | sync->in_sync = rc ? -EAGAIN : 1; |
576 | xchg(&first, 0); |
577 | } else { |
578 | /* Slave */ |
579 | atomic_dec(v: &sync->cpus); |
580 | /* Wait for in_sync to be set. */ |
581 | while (READ_ONCE(sync->in_sync) == 0) |
582 | __udelay(usecs: 1); |
583 | } |
584 | if (sync->in_sync != 1) |
585 | /* Didn't work. Clear per-cpu in sync bit again. */ |
586 | disable_sync_clock(NULL); |
587 | /* Apply clock delta to per-CPU fields of this CPU. */ |
588 | clock_sync_local(delta: sync->clock_delta); |
589 | |
590 | return 0; |
591 | } |
592 | |
593 | static int stp_clear_leap(void) |
594 | { |
595 | struct __kernel_timex txc; |
596 | int ret; |
597 | |
598 | memset(&txc, 0, sizeof(txc)); |
599 | |
600 | ret = do_adjtimex(&txc); |
601 | if (ret < 0) |
602 | return ret; |
603 | |
604 | txc.modes = ADJ_STATUS; |
605 | txc.status &= ~(STA_INS|STA_DEL); |
606 | return do_adjtimex(&txc); |
607 | } |
608 | |
609 | static void stp_check_leap(void) |
610 | { |
611 | struct stp_stzi stzi; |
612 | struct stp_lsoib *lsoib = &stzi.lsoib; |
613 | struct __kernel_timex txc; |
614 | int64_t timediff; |
615 | int leapdiff, ret; |
616 | |
617 | if (!stp_info.lu || !check_sync_clock()) { |
618 | /* |
619 | * Either a scheduled leap second was removed by the operator, |
620 | * or STP is out of sync. In both cases, clear the leap second |
621 | * kernel flags. |
622 | */ |
623 | if (stp_clear_leap() < 0) |
624 | pr_err("failed to clear leap second flags\n" ); |
625 | return; |
626 | } |
627 | |
628 | if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) { |
629 | pr_err("stzi failed\n" ); |
630 | return; |
631 | } |
632 | |
633 | timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC; |
634 | leapdiff = lsoib->nlso - lsoib->also; |
635 | |
636 | if (leapdiff != 1 && leapdiff != -1) { |
637 | pr_err("Cannot schedule %d leap seconds\n" , leapdiff); |
638 | return; |
639 | } |
640 | |
641 | if (timediff < 0) { |
642 | if (stp_clear_leap() < 0) |
643 | pr_err("failed to clear leap second flags\n" ); |
644 | } else if (timediff < 7200) { |
645 | memset(&txc, 0, sizeof(txc)); |
646 | ret = do_adjtimex(&txc); |
647 | if (ret < 0) |
648 | return; |
649 | |
650 | txc.modes = ADJ_STATUS; |
651 | if (leapdiff > 0) |
652 | txc.status |= STA_INS; |
653 | else |
654 | txc.status |= STA_DEL; |
655 | ret = do_adjtimex(&txc); |
656 | if (ret < 0) |
657 | pr_err("failed to set leap second flags\n" ); |
658 | /* arm Timer to clear leap second flags */ |
659 | mod_timer(timer: &stp_timer, expires: jiffies + msecs_to_jiffies(m: 14400 * MSEC_PER_SEC)); |
660 | } else { |
661 | /* The day the leap second is scheduled for hasn't been reached. Retry |
662 | * in one hour. |
663 | */ |
664 | mod_timer(timer: &stp_timer, expires: jiffies + msecs_to_jiffies(m: 3600 * MSEC_PER_SEC)); |
665 | } |
666 | } |
667 | |
668 | /* |
669 | * STP work. Check for the STP state and take over the clock |
670 | * synchronization if the STP clock source is usable. |
671 | */ |
672 | static void stp_work_fn(struct work_struct *work) |
673 | { |
674 | struct clock_sync_data stp_sync; |
675 | int rc; |
676 | |
677 | /* prevent multiple execution. */ |
678 | mutex_lock(&stp_mutex); |
679 | |
680 | if (!stp_online) { |
681 | chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL); |
682 | del_timer_sync(timer: &stp_timer); |
683 | goto out_unlock; |
684 | } |
685 | |
686 | rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xf0e0, NULL); |
687 | if (rc) |
688 | goto out_unlock; |
689 | |
690 | rc = __store_stpinfo(); |
691 | if (rc || stp_info.c == 0) |
692 | goto out_unlock; |
693 | |
694 | /* Skip synchronization if the clock is already in sync. */ |
695 | if (!check_sync_clock()) { |
696 | memset(&stp_sync, 0, sizeof(stp_sync)); |
697 | cpus_read_lock(); |
698 | atomic_set(v: &stp_sync.cpus, i: num_online_cpus() - 1); |
699 | stop_machine_cpuslocked(fn: stp_sync_clock, data: &stp_sync, cpu_online_mask); |
700 | cpus_read_unlock(); |
701 | } |
702 | |
703 | if (!check_sync_clock()) |
704 | /* |
705 | * There is a usable clock but the synchronization failed. |
706 | * Retry after a second. |
707 | */ |
708 | mod_timer(timer: &stp_timer, expires: jiffies + msecs_to_jiffies(MSEC_PER_SEC)); |
709 | else if (stp_info.lu) |
710 | stp_check_leap(); |
711 | |
712 | out_unlock: |
713 | mutex_unlock(lock: &stp_mutex); |
714 | } |
715 | |
716 | /* |
717 | * STP subsys sysfs interface functions |
718 | */ |
719 | static const struct bus_type stp_subsys = { |
720 | .name = "stp" , |
721 | .dev_name = "stp" , |
722 | }; |
723 | |
724 | static ssize_t ctn_id_show(struct device *dev, |
725 | struct device_attribute *attr, |
726 | char *buf) |
727 | { |
728 | ssize_t ret = -ENODATA; |
729 | |
730 | mutex_lock(&stp_mutex); |
731 | if (stpinfo_valid()) |
732 | ret = sprintf(buf, fmt: "%016lx\n" , |
733 | *(unsigned long *) stp_info.ctnid); |
734 | mutex_unlock(lock: &stp_mutex); |
735 | return ret; |
736 | } |
737 | |
738 | static DEVICE_ATTR_RO(ctn_id); |
739 | |
740 | static ssize_t ctn_type_show(struct device *dev, |
741 | struct device_attribute *attr, |
742 | char *buf) |
743 | { |
744 | ssize_t ret = -ENODATA; |
745 | |
746 | mutex_lock(&stp_mutex); |
747 | if (stpinfo_valid()) |
748 | ret = sprintf(buf, fmt: "%i\n" , stp_info.ctn); |
749 | mutex_unlock(lock: &stp_mutex); |
750 | return ret; |
751 | } |
752 | |
753 | static DEVICE_ATTR_RO(ctn_type); |
754 | |
755 | static ssize_t dst_offset_show(struct device *dev, |
756 | struct device_attribute *attr, |
757 | char *buf) |
758 | { |
759 | ssize_t ret = -ENODATA; |
760 | |
761 | mutex_lock(&stp_mutex); |
762 | if (stpinfo_valid() && (stp_info.vbits & 0x2000)) |
763 | ret = sprintf(buf, fmt: "%i\n" , (int)(s16) stp_info.dsto); |
764 | mutex_unlock(lock: &stp_mutex); |
765 | return ret; |
766 | } |
767 | |
768 | static DEVICE_ATTR_RO(dst_offset); |
769 | |
770 | static ssize_t leap_seconds_show(struct device *dev, |
771 | struct device_attribute *attr, |
772 | char *buf) |
773 | { |
774 | ssize_t ret = -ENODATA; |
775 | |
776 | mutex_lock(&stp_mutex); |
777 | if (stpinfo_valid() && (stp_info.vbits & 0x8000)) |
778 | ret = sprintf(buf, fmt: "%i\n" , (int)(s16) stp_info.leaps); |
779 | mutex_unlock(lock: &stp_mutex); |
780 | return ret; |
781 | } |
782 | |
783 | static DEVICE_ATTR_RO(leap_seconds); |
784 | |
785 | static ssize_t leap_seconds_scheduled_show(struct device *dev, |
786 | struct device_attribute *attr, |
787 | char *buf) |
788 | { |
789 | struct stp_stzi stzi; |
790 | ssize_t ret; |
791 | |
792 | mutex_lock(&stp_mutex); |
793 | if (!stpinfo_valid() || !(stp_info.vbits & 0x8000) || !stp_info.lu) { |
794 | mutex_unlock(lock: &stp_mutex); |
795 | return -ENODATA; |
796 | } |
797 | |
798 | ret = chsc_stzi(stp_page, &stzi, sizeof(stzi)); |
799 | mutex_unlock(lock: &stp_mutex); |
800 | if (ret < 0) |
801 | return ret; |
802 | |
803 | if (!stzi.lsoib.p) |
804 | return sprintf(buf, fmt: "0,0\n" ); |
805 | |
806 | return sprintf(buf, "%lu,%d\n" , |
807 | tod_to_ns(stzi.lsoib.nlsout - TOD_UNIX_EPOCH) / NSEC_PER_SEC, |
808 | stzi.lsoib.nlso - stzi.lsoib.also); |
809 | } |
810 | |
811 | static DEVICE_ATTR_RO(leap_seconds_scheduled); |
812 | |
813 | static ssize_t stratum_show(struct device *dev, |
814 | struct device_attribute *attr, |
815 | char *buf) |
816 | { |
817 | ssize_t ret = -ENODATA; |
818 | |
819 | mutex_lock(&stp_mutex); |
820 | if (stpinfo_valid()) |
821 | ret = sprintf(buf, fmt: "%i\n" , (int)(s16) stp_info.stratum); |
822 | mutex_unlock(lock: &stp_mutex); |
823 | return ret; |
824 | } |
825 | |
826 | static DEVICE_ATTR_RO(stratum); |
827 | |
828 | static ssize_t time_offset_show(struct device *dev, |
829 | struct device_attribute *attr, |
830 | char *buf) |
831 | { |
832 | ssize_t ret = -ENODATA; |
833 | |
834 | mutex_lock(&stp_mutex); |
835 | if (stpinfo_valid() && (stp_info.vbits & 0x0800)) |
836 | ret = sprintf(buf, fmt: "%i\n" , (int) stp_info.tto); |
837 | mutex_unlock(lock: &stp_mutex); |
838 | return ret; |
839 | } |
840 | |
841 | static DEVICE_ATTR_RO(time_offset); |
842 | |
843 | static ssize_t time_zone_offset_show(struct device *dev, |
844 | struct device_attribute *attr, |
845 | char *buf) |
846 | { |
847 | ssize_t ret = -ENODATA; |
848 | |
849 | mutex_lock(&stp_mutex); |
850 | if (stpinfo_valid() && (stp_info.vbits & 0x4000)) |
851 | ret = sprintf(buf, fmt: "%i\n" , (int)(s16) stp_info.tzo); |
852 | mutex_unlock(lock: &stp_mutex); |
853 | return ret; |
854 | } |
855 | |
856 | static DEVICE_ATTR_RO(time_zone_offset); |
857 | |
858 | static ssize_t timing_mode_show(struct device *dev, |
859 | struct device_attribute *attr, |
860 | char *buf) |
861 | { |
862 | ssize_t ret = -ENODATA; |
863 | |
864 | mutex_lock(&stp_mutex); |
865 | if (stpinfo_valid()) |
866 | ret = sprintf(buf, fmt: "%i\n" , stp_info.tmd); |
867 | mutex_unlock(lock: &stp_mutex); |
868 | return ret; |
869 | } |
870 | |
871 | static DEVICE_ATTR_RO(timing_mode); |
872 | |
873 | static ssize_t timing_state_show(struct device *dev, |
874 | struct device_attribute *attr, |
875 | char *buf) |
876 | { |
877 | ssize_t ret = -ENODATA; |
878 | |
879 | mutex_lock(&stp_mutex); |
880 | if (stpinfo_valid()) |
881 | ret = sprintf(buf, fmt: "%i\n" , stp_info.tst); |
882 | mutex_unlock(lock: &stp_mutex); |
883 | return ret; |
884 | } |
885 | |
886 | static DEVICE_ATTR_RO(timing_state); |
887 | |
888 | static ssize_t online_show(struct device *dev, |
889 | struct device_attribute *attr, |
890 | char *buf) |
891 | { |
892 | return sprintf(buf, fmt: "%i\n" , stp_online); |
893 | } |
894 | |
895 | static ssize_t online_store(struct device *dev, |
896 | struct device_attribute *attr, |
897 | const char *buf, size_t count) |
898 | { |
899 | unsigned int value; |
900 | |
901 | value = simple_strtoul(buf, NULL, 0); |
902 | if (value != 0 && value != 1) |
903 | return -EINVAL; |
904 | if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags)) |
905 | return -EOPNOTSUPP; |
906 | mutex_lock(&stp_mutex); |
907 | stp_online = value; |
908 | if (stp_online) |
909 | set_bit(CLOCK_SYNC_STP, addr: &clock_sync_flags); |
910 | else |
911 | clear_bit(CLOCK_SYNC_STP, addr: &clock_sync_flags); |
912 | queue_work(wq: time_sync_wq, work: &stp_work); |
913 | mutex_unlock(lock: &stp_mutex); |
914 | return count; |
915 | } |
916 | |
917 | /* |
918 | * Can't use DEVICE_ATTR because the attribute should be named |
919 | * stp/online but dev_attr_online already exists in this file .. |
920 | */ |
921 | static DEVICE_ATTR_RW(online); |
922 | |
923 | static struct attribute *stp_dev_attrs[] = { |
924 | &dev_attr_ctn_id.attr, |
925 | &dev_attr_ctn_type.attr, |
926 | &dev_attr_dst_offset.attr, |
927 | &dev_attr_leap_seconds.attr, |
928 | &dev_attr_online.attr, |
929 | &dev_attr_leap_seconds_scheduled.attr, |
930 | &dev_attr_stratum.attr, |
931 | &dev_attr_time_offset.attr, |
932 | &dev_attr_time_zone_offset.attr, |
933 | &dev_attr_timing_mode.attr, |
934 | &dev_attr_timing_state.attr, |
935 | NULL |
936 | }; |
937 | ATTRIBUTE_GROUPS(stp_dev); |
938 | |
939 | static int __init stp_init_sysfs(void) |
940 | { |
941 | return subsys_system_register(subsys: &stp_subsys, groups: stp_dev_groups); |
942 | } |
943 | |
944 | device_initcall(stp_init_sysfs); |
945 | |