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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Common time routines among all ppc machines.
4 *
5 * Written by Cort Dougan (cort@cs.nmt.edu) to merge
6 * Paul Mackerras' version and mine for PReP and Pmac.
7 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
8 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
9 *
10 * First round of bugfixes by Gabriel Paubert (paubert@iram.es)
11 * to make clock more stable (2.4.0-test5). The only thing
12 * that this code assumes is that the timebases have been synchronized
13 * by firmware on SMP and are never stopped (never do sleep
14 * on SMP then, nap and doze are OK).
15 *
16 * Speeded up do_gettimeofday by getting rid of references to
17 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
18 *
19 * TODO (not necessarily in this file):
20 * - improve precision and reproducibility of timebase frequency
21 * measurement at boot time.
22 * - for astronomical applications: add a new function to get
23 * non ambiguous timestamps even around leap seconds. This needs
24 * a new timestamp format and a good name.
25 *
26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
27 * "A Kernel Model for Precision Timekeeping" by Dave Mills
28 */
29
30#include <linux/errno.h>
31#include <linux/export.h>
32#include <linux/sched.h>
33#include <linux/sched/clock.h>
34#include <linux/kernel.h>
35#include <linux/param.h>
36#include <linux/string.h>
37#include <linux/mm.h>
38#include <linux/interrupt.h>
39#include <linux/timex.h>
40#include <linux/kernel_stat.h>
41#include <linux/time.h>
42#include <linux/init.h>
43#include <linux/profile.h>
44#include <linux/cpu.h>
45#include <linux/security.h>
46#include <linux/percpu.h>
47#include <linux/rtc.h>
48#include <linux/jiffies.h>
49#include <linux/posix-timers.h>
50#include <linux/irq.h>
51#include <linux/delay.h>
52#include <linux/irq_work.h>
53#include <linux/of_clk.h>
54#include <linux/suspend.h>
55#include <linux/sched/cputime.h>
56#include <linux/processor.h>
57#include <asm/trace.h>
58
59#include <asm/io.h>
60#include <asm/nvram.h>
61#include <asm/cache.h>
62#include <asm/machdep.h>
63#include <linux/uaccess.h>
64#include <asm/time.h>
65#include <asm/prom.h>
66#include <asm/irq.h>
67#include <asm/div64.h>
68#include <asm/smp.h>
69#include <asm/vdso_datapage.h>
70#include <asm/firmware.h>
71#include <asm/asm-prototypes.h>
72
73/* powerpc clocksource/clockevent code */
74
75#include <linux/clockchips.h>
76#include <linux/timekeeper_internal.h>
77
78static u64 rtc_read(struct clocksource *);
79static struct clocksource clocksource_rtc = {
80 .name = "rtc",
81 .rating = 400,
82 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
83 .mask = CLOCKSOURCE_MASK(64),
84 .read = rtc_read,
85};
86
87static u64 timebase_read(struct clocksource *);
88static struct clocksource clocksource_timebase = {
89 .name = "timebase",
90 .rating = 400,
91 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
92 .mask = CLOCKSOURCE_MASK(64),
93 .read = timebase_read,
94};
95
96#define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF
97u64 decrementer_max = DECREMENTER_DEFAULT_MAX;
98
99static int decrementer_set_next_event(unsigned long evt,
100 struct clock_event_device *dev);
101static int decrementer_shutdown(struct clock_event_device *evt);
102
103struct clock_event_device decrementer_clockevent = {
104 .name = "decrementer",
105 .rating = 200,
106 .irq = 0,
107 .set_next_event = decrementer_set_next_event,
108 .set_state_oneshot_stopped = decrementer_shutdown,
109 .set_state_shutdown = decrementer_shutdown,
110 .tick_resume = decrementer_shutdown,
111 .features = CLOCK_EVT_FEAT_ONESHOT |
112 CLOCK_EVT_FEAT_C3STOP,
113};
114EXPORT_SYMBOL(decrementer_clockevent);
115
116DEFINE_PER_CPU(u64, decrementers_next_tb);
117static DEFINE_PER_CPU(struct clock_event_device, decrementers);
118
119#define XSEC_PER_SEC (1024*1024)
120
121#ifdef CONFIG_PPC64
122#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
123#else
124/* compute ((xsec << 12) * max) >> 32 */
125#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
126#endif
127
128unsigned long tb_ticks_per_jiffy;
129unsigned long tb_ticks_per_usec = 100; /* sane default */
130EXPORT_SYMBOL(tb_ticks_per_usec);
131unsigned long tb_ticks_per_sec;
132EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
133
134DEFINE_SPINLOCK(rtc_lock);
135EXPORT_SYMBOL_GPL(rtc_lock);
136
137static u64 tb_to_ns_scale __read_mostly;
138static unsigned tb_to_ns_shift __read_mostly;
139static u64 boot_tb __read_mostly;
140
141extern struct timezone sys_tz;
142static long timezone_offset;
143
144unsigned long ppc_proc_freq;
145EXPORT_SYMBOL_GPL(ppc_proc_freq);
146unsigned long ppc_tb_freq;
147EXPORT_SYMBOL_GPL(ppc_tb_freq);
148
149bool tb_invalid;
150
151#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
152/*
153 * Factor for converting from cputime_t (timebase ticks) to
154 * microseconds. This is stored as 0.64 fixed-point binary fraction.
155 */
156u64 __cputime_usec_factor;
157EXPORT_SYMBOL(__cputime_usec_factor);
158
159#ifdef CONFIG_PPC_SPLPAR
160void (*dtl_consumer)(struct dtl_entry *, u64);
161#endif
162
163static void calc_cputime_factors(void)
164{
165 struct div_result res;
166
167 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
168 __cputime_usec_factor = res.result_low;
169}
170
171/*
172 * Read the SPURR on systems that have it, otherwise the PURR,
173 * or if that doesn't exist return the timebase value passed in.
174 */
175static inline unsigned long read_spurr(unsigned long tb)
176{
177 if (cpu_has_feature(CPU_FTR_SPURR))
178 return mfspr(SPRN_SPURR);
179 if (cpu_has_feature(CPU_FTR_PURR))
180 return mfspr(SPRN_PURR);
181 return tb;
182}
183
184#ifdef CONFIG_PPC_SPLPAR
185
186#include <asm/dtl.h>
187
188/*
189 * Scan the dispatch trace log and count up the stolen time.
190 * Should be called with interrupts disabled.
191 */
192static u64 scan_dispatch_log(u64 stop_tb)
193{
194 u64 i = local_paca->dtl_ridx;
195 struct dtl_entry *dtl = local_paca->dtl_curr;
196 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
197 struct lppaca *vpa = local_paca->lppaca_ptr;
198 u64 tb_delta;
199 u64 stolen = 0;
200 u64 dtb;
201
202 if (!dtl)
203 return 0;
204
205 if (i == be64_to_cpu(vpa->dtl_idx))
206 return 0;
207 while (i < be64_to_cpu(vpa->dtl_idx)) {
208 dtb = be64_to_cpu(dtl->timebase);
209 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) +
210 be32_to_cpu(dtl->ready_to_enqueue_time);
211 barrier();
212 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) {
213 /* buffer has overflowed */
214 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG;
215 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
216 continue;
217 }
218 if (dtb > stop_tb)
219 break;
220 if (dtl_consumer)
221 dtl_consumer(dtl, i);
222 stolen += tb_delta;
223 ++i;
224 ++dtl;
225 if (dtl == dtl_end)
226 dtl = local_paca->dispatch_log;
227 }
228 local_paca->dtl_ridx = i;
229 local_paca->dtl_curr = dtl;
230 return stolen;
231}
232
233/*
234 * Accumulate stolen time by scanning the dispatch trace log.
235 * Called on entry from user mode.
236 */
237void notrace accumulate_stolen_time(void)
238{
239 u64 sst, ust;
240 unsigned long save_irq_soft_mask = irq_soft_mask_return();
241 struct cpu_accounting_data *acct = &local_paca->accounting;
242
243 /* We are called early in the exception entry, before
244 * soft/hard_enabled are sync'ed to the expected state
245 * for the exception. We are hard disabled but the PACA
246 * needs to reflect that so various debug stuff doesn't
247 * complain
248 */
249 irq_soft_mask_set(IRQS_DISABLED);
250
251 sst = scan_dispatch_log(acct->starttime_user);
252 ust = scan_dispatch_log(acct->starttime);
253 acct->stime -= sst;
254 acct->utime -= ust;
255 acct->steal_time += ust + sst;
256
257 irq_soft_mask_set(save_irq_soft_mask);
258}
259
260static inline u64 calculate_stolen_time(u64 stop_tb)
261{
262 if (!firmware_has_feature(FW_FEATURE_SPLPAR))
263 return 0;
264
265 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx))
266 return scan_dispatch_log(stop_tb);
267
268 return 0;
269}
270
271#else /* CONFIG_PPC_SPLPAR */
272static inline u64 calculate_stolen_time(u64 stop_tb)
273{
274 return 0;
275}
276
277#endif /* CONFIG_PPC_SPLPAR */
278
279/*
280 * Account time for a transition between system, hard irq
281 * or soft irq state.
282 */
283static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct,
284 unsigned long now, unsigned long stime)
285{
286 unsigned long stime_scaled = 0;
287#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
288 unsigned long nowscaled, deltascaled;
289 unsigned long utime, utime_scaled;
290
291 nowscaled = read_spurr(now);
292 deltascaled = nowscaled - acct->startspurr;
293 acct->startspurr = nowscaled;
294 utime = acct->utime - acct->utime_sspurr;
295 acct->utime_sspurr = acct->utime;
296
297 /*
298 * Because we don't read the SPURR on every kernel entry/exit,
299 * deltascaled includes both user and system SPURR ticks.
300 * Apportion these ticks to system SPURR ticks and user
301 * SPURR ticks in the same ratio as the system time (delta)
302 * and user time (udelta) values obtained from the timebase
303 * over the same interval. The system ticks get accounted here;
304 * the user ticks get saved up in paca->user_time_scaled to be
305 * used by account_process_tick.
306 */
307 stime_scaled = stime;
308 utime_scaled = utime;
309 if (deltascaled != stime + utime) {
310 if (utime) {
311 stime_scaled = deltascaled * stime / (stime + utime);
312 utime_scaled = deltascaled - stime_scaled;
313 } else {
314 stime_scaled = deltascaled;
315 }
316 }
317 acct->utime_scaled += utime_scaled;
318#endif
319
320 return stime_scaled;
321}
322
323static unsigned long vtime_delta(struct task_struct *tsk,
324 unsigned long *stime_scaled,
325 unsigned long *steal_time)
326{
327 unsigned long now, stime;
328 struct cpu_accounting_data *acct = get_accounting(tsk);
329
330 WARN_ON_ONCE(!irqs_disabled());
331
332 now = mftb();
333 stime = now - acct->starttime;
334 acct->starttime = now;
335
336 *stime_scaled = vtime_delta_scaled(acct, now, stime);
337
338 *steal_time = calculate_stolen_time(now);
339
340 return stime;
341}
342
343void vtime_account_kernel(struct task_struct *tsk)
344{
345 unsigned long stime, stime_scaled, steal_time;
346 struct cpu_accounting_data *acct = get_accounting(tsk);
347
348 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
349
350 stime -= min(stime, steal_time);
351 acct->steal_time += steal_time;
352
353 if ((tsk->flags & PF_VCPU) && !irq_count()) {
354 acct->gtime += stime;
355#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
356 acct->utime_scaled += stime_scaled;
357#endif
358 } else {
359 if (hardirq_count())
360 acct->hardirq_time += stime;
361 else if (in_serving_softirq())
362 acct->softirq_time += stime;
363 else
364 acct->stime += stime;
365
366#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
367 acct->stime_scaled += stime_scaled;
368#endif
369 }
370}
371EXPORT_SYMBOL_GPL(vtime_account_kernel);
372
373void vtime_account_idle(struct task_struct *tsk)
374{
375 unsigned long stime, stime_scaled, steal_time;
376 struct cpu_accounting_data *acct = get_accounting(tsk);
377
378 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
379 acct->idle_time += stime + steal_time;
380}
381
382static void vtime_flush_scaled(struct task_struct *tsk,
383 struct cpu_accounting_data *acct)
384{
385#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
386 if (acct->utime_scaled)
387 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
388 if (acct->stime_scaled)
389 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
390
391 acct->utime_scaled = 0;
392 acct->utime_sspurr = 0;
393 acct->stime_scaled = 0;
394#endif
395}
396
397/*
398 * Account the whole cputime accumulated in the paca
399 * Must be called with interrupts disabled.
400 * Assumes that vtime_account_kernel/idle() has been called
401 * recently (i.e. since the last entry from usermode) so that
402 * get_paca()->user_time_scaled is up to date.
403 */
404void vtime_flush(struct task_struct *tsk)
405{
406 struct cpu_accounting_data *acct = get_accounting(tsk);
407
408 if (acct->utime)
409 account_user_time(tsk, cputime_to_nsecs(acct->utime));
410
411 if (acct->gtime)
412 account_guest_time(tsk, cputime_to_nsecs(acct->gtime));
413
414 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) {
415 account_steal_time(cputime_to_nsecs(acct->steal_time));
416 acct->steal_time = 0;
417 }
418
419 if (acct->idle_time)
420 account_idle_time(cputime_to_nsecs(acct->idle_time));
421
422 if (acct->stime)
423 account_system_index_time(tsk, cputime_to_nsecs(acct->stime),
424 CPUTIME_SYSTEM);
425
426 if (acct->hardirq_time)
427 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time),
428 CPUTIME_IRQ);
429 if (acct->softirq_time)
430 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time),
431 CPUTIME_SOFTIRQ);
432
433 vtime_flush_scaled(tsk, acct);
434
435 acct->utime = 0;
436 acct->gtime = 0;
437 acct->idle_time = 0;
438 acct->stime = 0;
439 acct->hardirq_time = 0;
440 acct->softirq_time = 0;
441}
442
443#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
444#define calc_cputime_factors()
445#endif
446
447void __delay(unsigned long loops)
448{
449 unsigned long start;
450 int diff;
451
452 spin_begin();
453 if (__USE_RTC()) {
454 start = get_rtcl();
455 do {
456 /* the RTCL register wraps at 1000000000 */
457 diff = get_rtcl() - start;
458 if (diff < 0)
459 diff += 1000000000;
460 spin_cpu_relax();
461 } while (diff < loops);
462 } else if (tb_invalid) {
463 /*
464 * TB is in error state and isn't ticking anymore.
465 * HMI handler was unable to recover from TB error.
466 * Return immediately, so that kernel won't get stuck here.
467 */
468 spin_cpu_relax();
469 } else {
470 start = get_tbl();
471 while (get_tbl() - start < loops)
472 spin_cpu_relax();
473 }
474 spin_end();
475}
476EXPORT_SYMBOL(__delay);
477
478void udelay(unsigned long usecs)
479{
480 __delay(tb_ticks_per_usec * usecs);
481}
482EXPORT_SYMBOL(udelay);
483
484#ifdef CONFIG_SMP
485unsigned long profile_pc(struct pt_regs *regs)
486{
487 unsigned long pc = instruction_pointer(regs);
488
489 if (in_lock_functions(pc))
490 return regs->link;
491
492 return pc;
493}
494EXPORT_SYMBOL(profile_pc);
495#endif
496
497#ifdef CONFIG_IRQ_WORK
498
499/*
500 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
501 */
502#ifdef CONFIG_PPC64
503static inline unsigned long test_irq_work_pending(void)
504{
505 unsigned long x;
506
507 asm volatile("lbz %0,%1(13)"
508 : "=r" (x)
509 : "i" (offsetof(struct paca_struct, irq_work_pending)));
510 return x;
511}
512
513static inline void set_irq_work_pending_flag(void)
514{
515 asm volatile("stb %0,%1(13)" : :
516 "r" (1),
517 "i" (offsetof(struct paca_struct, irq_work_pending)));
518}
519
520static inline void clear_irq_work_pending(void)
521{
522 asm volatile("stb %0,%1(13)" : :
523 "r" (0),
524 "i" (offsetof(struct paca_struct, irq_work_pending)));
525}
526
527#else /* 32-bit */
528
529DEFINE_PER_CPU(u8, irq_work_pending);
530
531#define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1)
532#define test_irq_work_pending() __this_cpu_read(irq_work_pending)
533#define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
534
535#endif /* 32 vs 64 bit */
536
537void arch_irq_work_raise(void)
538{
539 /*
540 * 64-bit code that uses irq soft-mask can just cause an immediate
541 * interrupt here that gets soft masked, if this is called under
542 * local_irq_disable(). It might be possible to prevent that happening
543 * by noticing interrupts are disabled and setting decrementer pending
544 * to be replayed when irqs are enabled. The problem there is that
545 * tracing can call irq_work_raise, including in code that does low
546 * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on)
547 * which could get tangled up if we're messing with the same state
548 * here.
549 */
550 preempt_disable();
551 set_irq_work_pending_flag();
552 set_dec(1);
553 preempt_enable();
554}
555
556#else /* CONFIG_IRQ_WORK */
557
558#define test_irq_work_pending() 0
559#define clear_irq_work_pending()
560
561#endif /* CONFIG_IRQ_WORK */
562
563/*
564 * timer_interrupt - gets called when the decrementer overflows,
565 * with interrupts disabled.
566 */
567void timer_interrupt(struct pt_regs *regs)
568{
569 struct clock_event_device *evt = this_cpu_ptr(&decrementers);
570 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
571 struct pt_regs *old_regs;
572 u64 now;
573
574 /* Some implementations of hotplug will get timer interrupts while
575 * offline, just ignore these and we also need to set
576 * decrementers_next_tb as MAX to make sure __check_irq_replay
577 * don't replay timer interrupt when return, otherwise we'll trap
578 * here infinitely :(
579 */
580 if (unlikely(!cpu_online(smp_processor_id()))) {
581 *next_tb = ~(u64)0;
582 set_dec(decrementer_max);
583 return;
584 }
585
586 /* Ensure a positive value is written to the decrementer, or else
587 * some CPUs will continue to take decrementer exceptions. When the
588 * PPC_WATCHDOG (decrementer based) is configured, keep this at most
589 * 31 bits, which is about 4 seconds on most systems, which gives
590 * the watchdog a chance of catching timer interrupt hard lockups.
591 */
592 if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
593 set_dec(0x7fffffff);
594 else
595 set_dec(decrementer_max);
596
597 /* Conditionally hard-enable interrupts now that the DEC has been
598 * bumped to its maximum value
599 */
600 may_hard_irq_enable();
601
602
603#if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC)
604 if (atomic_read(&ppc_n_lost_interrupts) != 0)
605 do_IRQ(regs);
606#endif
607
608 old_regs = set_irq_regs(regs);
609 irq_enter();
610 trace_timer_interrupt_entry(regs);
611
612 if (test_irq_work_pending()) {
613 clear_irq_work_pending();
614 irq_work_run();
615 }
616
617 now = get_tb_or_rtc();
618 if (now >= *next_tb) {
619 *next_tb = ~(u64)0;
620 if (evt->event_handler)
621 evt->event_handler(evt);
622 __this_cpu_inc(irq_stat.timer_irqs_event);
623 } else {
624 now = *next_tb - now;
625 if (now <= decrementer_max)
626 set_dec(now);
627 /* We may have raced with new irq work */
628 if (test_irq_work_pending())
629 set_dec(1);
630 __this_cpu_inc(irq_stat.timer_irqs_others);
631 }
632
633 trace_timer_interrupt_exit(regs);
634 irq_exit();
635 set_irq_regs(old_regs);
636}
637EXPORT_SYMBOL(timer_interrupt);
638
639#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
640void timer_broadcast_interrupt(void)
641{
642 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
643
644 *next_tb = ~(u64)0;
645 tick_receive_broadcast();
646 __this_cpu_inc(irq_stat.broadcast_irqs_event);
647}
648#endif
649
650#ifdef CONFIG_SUSPEND
651static void generic_suspend_disable_irqs(void)
652{
653 /* Disable the decrementer, so that it doesn't interfere
654 * with suspending.
655 */
656
657 set_dec(decrementer_max);
658 local_irq_disable();
659 set_dec(decrementer_max);
660}
661
662static void generic_suspend_enable_irqs(void)
663{
664 local_irq_enable();
665}
666
667/* Overrides the weak version in kernel/power/main.c */
668void arch_suspend_disable_irqs(void)
669{
670 if (ppc_md.suspend_disable_irqs)
671 ppc_md.suspend_disable_irqs();
672 generic_suspend_disable_irqs();
673}
674
675/* Overrides the weak version in kernel/power/main.c */
676void arch_suspend_enable_irqs(void)
677{
678 generic_suspend_enable_irqs();
679 if (ppc_md.suspend_enable_irqs)
680 ppc_md.suspend_enable_irqs();
681}
682#endif
683
684unsigned long long tb_to_ns(unsigned long long ticks)
685{
686 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift;
687}
688EXPORT_SYMBOL_GPL(tb_to_ns);
689
690/*
691 * Scheduler clock - returns current time in nanosec units.
692 *
693 * Note: mulhdu(a, b) (multiply high double unsigned) returns
694 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
695 * are 64-bit unsigned numbers.
696 */
697notrace unsigned long long sched_clock(void)
698{
699 if (__USE_RTC())
700 return get_rtc();
701 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
702}
703
704
705#ifdef CONFIG_PPC_PSERIES
706
707/*
708 * Running clock - attempts to give a view of time passing for a virtualised
709 * kernels.
710 * Uses the VTB register if available otherwise a next best guess.
711 */
712unsigned long long running_clock(void)
713{
714 /*
715 * Don't read the VTB as a host since KVM does not switch in host
716 * timebase into the VTB when it takes a guest off the CPU, reading the
717 * VTB would result in reading 'last switched out' guest VTB.
718 *
719 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
720 * would be unsafe to rely only on the #ifdef above.
721 */
722 if (firmware_has_feature(FW_FEATURE_LPAR) &&
723 cpu_has_feature(CPU_FTR_ARCH_207S))
724 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
725
726 /*
727 * This is a next best approximation without a VTB.
728 * On a host which is running bare metal there should never be any stolen
729 * time and on a host which doesn't do any virtualisation TB *should* equal
730 * VTB so it makes no difference anyway.
731 */
732 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL];
733}
734#endif
735
736static int __init get_freq(char *name, int cells, unsigned long *val)
737{
738 struct device_node *cpu;
739 const __be32 *fp;
740 int found = 0;
741
742 /* The cpu node should have timebase and clock frequency properties */
743 cpu = of_find_node_by_type(NULL, "cpu");
744
745 if (cpu) {
746 fp = of_get_property(cpu, name, NULL);
747 if (fp) {
748 found = 1;
749 *val = of_read_ulong(fp, cells);
750 }
751
752 of_node_put(cpu);
753 }
754
755 return found;
756}
757
758static void start_cpu_decrementer(void)
759{
760#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
761 unsigned int tcr;
762
763 /* Clear any pending timer interrupts */
764 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
765
766 tcr = mfspr(SPRN_TCR);
767 /*
768 * The watchdog may have already been enabled by u-boot. So leave
769 * TRC[WP] (Watchdog Period) alone.
770 */
771 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */
772 tcr |= TCR_DIE; /* Enable decrementer */
773 mtspr(SPRN_TCR, tcr);
774#endif
775}
776
777void __init generic_calibrate_decr(void)
778{
779 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
780
781 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
782 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
783
784 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
785 "(not found)\n");
786 }
787
788 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
789
790 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
791 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
792
793 printk(KERN_ERR "WARNING: Estimating processor frequency "
794 "(not found)\n");
795 }
796}
797
798int update_persistent_clock64(struct timespec64 now)
799{
800 struct rtc_time tm;
801
802 if (!ppc_md.set_rtc_time)
803 return -ENODEV;
804
805 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm);
806
807 return ppc_md.set_rtc_time(&tm);
808}
809
810static void __read_persistent_clock(struct timespec64 *ts)
811{
812 struct rtc_time tm;
813 static int first = 1;
814
815 ts->tv_nsec = 0;
816 /* XXX this is a litle fragile but will work okay in the short term */
817 if (first) {
818 first = 0;
819 if (ppc_md.time_init)
820 timezone_offset = ppc_md.time_init();
821
822 /* get_boot_time() isn't guaranteed to be safe to call late */
823 if (ppc_md.get_boot_time) {
824 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
825 return;
826 }
827 }
828 if (!ppc_md.get_rtc_time) {
829 ts->tv_sec = 0;
830 return;
831 }
832 ppc_md.get_rtc_time(&tm);
833
834 ts->tv_sec = rtc_tm_to_time64(&tm);
835}
836
837void read_persistent_clock64(struct timespec64 *ts)
838{
839 __read_persistent_clock(ts);
840
841 /* Sanitize it in case real time clock is set below EPOCH */
842 if (ts->tv_sec < 0) {
843 ts->tv_sec = 0;
844 ts->tv_nsec = 0;
845 }
846
847}
848
849/* clocksource code */
850static notrace u64 rtc_read(struct clocksource *cs)
851{
852 return (u64)get_rtc();
853}
854
855static notrace u64 timebase_read(struct clocksource *cs)
856{
857 return (u64)get_tb();
858}
859
860
861void update_vsyscall(struct timekeeper *tk)
862{
863 struct timespec64 xt;
864 struct clocksource *clock = tk->tkr_mono.clock;
865 u32 mult = tk->tkr_mono.mult;
866 u32 shift = tk->tkr_mono.shift;
867 u64 cycle_last = tk->tkr_mono.cycle_last;
868 u64 new_tb_to_xs, new_stamp_xsec;
869 u64 frac_sec;
870
871 if (clock != &clocksource_timebase)
872 return;
873
874 xt.tv_sec = tk->xtime_sec;
875 xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
876
877 /* Make userspace gettimeofday spin until we're done. */
878 ++vdso_data->tb_update_count;
879 smp_mb();
880
881 /*
882 * This computes ((2^20 / 1e9) * mult) >> shift as a
883 * 0.64 fixed-point fraction.
884 * The computation in the else clause below won't overflow
885 * (as long as the timebase frequency is >= 1.049 MHz)
886 * but loses precision because we lose the low bits of the constant
887 * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9.
888 * For a shift of 24 the error is about 0.5e-9, or about 0.5ns
889 * over a second. (Shift values are usually 22, 23 or 24.)
890 * For high frequency clocks such as the 512MHz timebase clock
891 * on POWER[6789], the mult value is small (e.g. 32768000)
892 * and so we can shift the constant by 16 initially
893 * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the
894 * remaining shifts after the multiplication, which gives a
895 * more accurate result (e.g. with mult = 32768000, shift = 24,
896 * the error is only about 1.2e-12, or 0.7ns over 10 minutes).
897 */
898 if (mult <= 62500000 && clock->shift >= 16)
899 new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16);
900 else
901 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
902
903 /*
904 * Compute the fractional second in units of 2^-32 seconds.
905 * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift
906 * in nanoseconds, so multiplying that by 2^32 / 1e9 gives
907 * it in units of 2^-32 seconds.
908 * We assume shift <= 32 because clocks_calc_mult_shift()
909 * generates shift values in the range 0 - 32.
910 */
911 frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift);
912 do_div(frac_sec, NSEC_PER_SEC);
913
914 /*
915 * Work out new stamp_xsec value for any legacy users of systemcfg.
916 * stamp_xsec is in units of 2^-20 seconds.
917 */
918 new_stamp_xsec = frac_sec >> 12;
919 new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC;
920
921 /*
922 * tb_update_count is used to allow the userspace gettimeofday code
923 * to assure itself that it sees a consistent view of the tb_to_xs and
924 * stamp_xsec variables. It reads the tb_update_count, then reads
925 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
926 * the two values of tb_update_count match and are even then the
927 * tb_to_xs and stamp_xsec values are consistent. If not, then it
928 * loops back and reads them again until this criteria is met.
929 */
930 vdso_data->tb_orig_stamp = cycle_last;
931 vdso_data->stamp_xsec = new_stamp_xsec;
932 vdso_data->tb_to_xs = new_tb_to_xs;
933 vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
934 vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
935 vdso_data->stamp_xtime_sec = xt.tv_sec;
936 vdso_data->stamp_xtime_nsec = xt.tv_nsec;
937 vdso_data->stamp_sec_fraction = frac_sec;
938 vdso_data->hrtimer_res = hrtimer_resolution;
939 smp_wmb();
940 ++(vdso_data->tb_update_count);
941}
942
943void update_vsyscall_tz(void)
944{
945 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
946 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
947}
948
949static void __init clocksource_init(void)
950{
951 struct clocksource *clock;
952
953 if (__USE_RTC())
954 clock = &clocksource_rtc;
955 else
956 clock = &clocksource_timebase;
957
958 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
959 printk(KERN_ERR "clocksource: %s is already registered\n",
960 clock->name);
961 return;
962 }
963
964 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
965 clock->name, clock->mult, clock->shift);
966}
967
968static int decrementer_set_next_event(unsigned long evt,
969 struct clock_event_device *dev)
970{
971 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt);
972 set_dec(evt);
973
974 /* We may have raced with new irq work */
975 if (test_irq_work_pending())
976 set_dec(1);
977
978 return 0;
979}
980
981static int decrementer_shutdown(struct clock_event_device *dev)
982{
983 decrementer_set_next_event(decrementer_max, dev);
984 return 0;
985}
986
987static void register_decrementer_clockevent(int cpu)
988{
989 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
990
991 *dec = decrementer_clockevent;
992 dec->cpumask = cpumask_of(cpu);
993
994 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max);
995
996 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
997 dec->name, dec->mult, dec->shift, cpu);
998
999 /* Set values for KVM, see kvm_emulate_dec() */
1000 decrementer_clockevent.mult = dec->mult;
1001 decrementer_clockevent.shift = dec->shift;
1002}
1003
1004static void enable_large_decrementer(void)
1005{
1006 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1007 return;
1008
1009 if (decrementer_max <= DECREMENTER_DEFAULT_MAX)
1010 return;
1011
1012 /*
1013 * If we're running as the hypervisor we need to enable the LD manually
1014 * otherwise firmware should have done it for us.
1015 */
1016 if (cpu_has_feature(CPU_FTR_HVMODE))
1017 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD);
1018}
1019
1020static void __init set_decrementer_max(void)
1021{
1022 struct device_node *cpu;
1023 u32 bits = 32;
1024
1025 /* Prior to ISAv3 the decrementer is always 32 bit */
1026 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1027 return;
1028
1029 cpu = of_find_node_by_type(NULL, "cpu");
1030
1031 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) {
1032 if (bits > 64 || bits < 32) {
1033 pr_warn("time_init: firmware supplied invalid ibm,dec-bits");
1034 bits = 32;
1035 }
1036
1037 /* calculate the signed maximum given this many bits */
1038 decrementer_max = (1ul << (bits - 1)) - 1;
1039 }
1040
1041 of_node_put(cpu);
1042
1043 pr_info("time_init: %u bit decrementer (max: %llx)\n",
1044 bits, decrementer_max);
1045}
1046
1047static void __init init_decrementer_clockevent(void)
1048{
1049 register_decrementer_clockevent(smp_processor_id());
1050}
1051
1052void secondary_cpu_time_init(void)
1053{
1054 /* Enable and test the large decrementer for this cpu */
1055 enable_large_decrementer();
1056
1057 /* Start the decrementer on CPUs that have manual control
1058 * such as BookE
1059 */
1060 start_cpu_decrementer();
1061
1062 /* FIME: Should make unrelatred change to move snapshot_timebase
1063 * call here ! */
1064 register_decrementer_clockevent(smp_processor_id());
1065}
1066
1067/* This function is only called on the boot processor */
1068void __init time_init(void)
1069{
1070 struct div_result res;
1071 u64 scale;
1072 unsigned shift;
1073
1074 if (__USE_RTC()) {
1075 /* 601 processor: dec counts down by 128 every 128ns */
1076 ppc_tb_freq = 1000000000;
1077 } else {
1078 /* Normal PowerPC with timebase register */
1079 ppc_md.calibrate_decr();
1080 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
1081 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
1082 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
1083 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
1084 }
1085
1086 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
1087 tb_ticks_per_sec = ppc_tb_freq;
1088 tb_ticks_per_usec = ppc_tb_freq / 1000000;
1089 calc_cputime_factors();
1090
1091 /*
1092 * Compute scale factor for sched_clock.
1093 * The calibrate_decr() function has set tb_ticks_per_sec,
1094 * which is the timebase frequency.
1095 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
1096 * the 128-bit result as a 64.64 fixed-point number.
1097 * We then shift that number right until it is less than 1.0,
1098 * giving us the scale factor and shift count to use in
1099 * sched_clock().
1100 */
1101 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
1102 scale = res.result_low;
1103 for (shift = 0; res.result_high != 0; ++shift) {
1104 scale = (scale >> 1) | (res.result_high << 63);
1105 res.result_high >>= 1;
1106 }
1107 tb_to_ns_scale = scale;
1108 tb_to_ns_shift = shift;
1109 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
1110 boot_tb = get_tb_or_rtc();
1111
1112 /* If platform provided a timezone (pmac), we correct the time */
1113 if (timezone_offset) {
1114 sys_tz.tz_minuteswest = -timezone_offset / 60;
1115 sys_tz.tz_dsttime = 0;
1116 }
1117
1118 vdso_data->tb_update_count = 0;
1119 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
1120
1121 /* initialise and enable the large decrementer (if we have one) */
1122 set_decrementer_max();
1123 enable_large_decrementer();
1124
1125 /* Start the decrementer on CPUs that have manual control
1126 * such as BookE
1127 */
1128 start_cpu_decrementer();
1129
1130 /* Register the clocksource */
1131 clocksource_init();
1132
1133 init_decrementer_clockevent();
1134 tick_setup_hrtimer_broadcast();
1135
1136 of_clk_init(NULL);
1137}
1138
1139/*
1140 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1141 * result.
1142 */
1143void div128_by_32(u64 dividend_high, u64 dividend_low,
1144 unsigned divisor, struct div_result *dr)
1145{
1146 unsigned long a, b, c, d;
1147 unsigned long w, x, y, z;
1148 u64 ra, rb, rc;
1149
1150 a = dividend_high >> 32;
1151 b = dividend_high & 0xffffffff;
1152 c = dividend_low >> 32;
1153 d = dividend_low & 0xffffffff;
1154
1155 w = a / divisor;
1156 ra = ((u64)(a - (w * divisor)) << 32) + b;
1157
1158 rb = ((u64) do_div(ra, divisor) << 32) + c;
1159 x = ra;
1160
1161 rc = ((u64) do_div(rb, divisor) << 32) + d;
1162 y = rb;
1163
1164 do_div(rc, divisor);
1165 z = rc;
1166
1167 dr->result_high = ((u64)w << 32) + x;
1168 dr->result_low = ((u64)y << 32) + z;
1169
1170}
1171
1172/* We don't need to calibrate delay, we use the CPU timebase for that */
1173void calibrate_delay(void)
1174{
1175 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1176 * as the number of __delay(1) in a jiffy, so make it so
1177 */
1178 loops_per_jiffy = tb_ticks_per_jiffy;
1179}
1180
1181#if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
1182static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
1183{
1184 ppc_md.get_rtc_time(tm);
1185 return 0;
1186}
1187
1188static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
1189{
1190 if (!ppc_md.set_rtc_time)
1191 return -EOPNOTSUPP;
1192
1193 if (ppc_md.set_rtc_time(tm) < 0)
1194 return -EOPNOTSUPP;
1195
1196 return 0;
1197}
1198
1199static const struct rtc_class_ops rtc_generic_ops = {
1200 .read_time = rtc_generic_get_time,
1201 .set_time = rtc_generic_set_time,
1202};
1203
1204static int __init rtc_init(void)
1205{
1206 struct platform_device *pdev;
1207
1208 if (!ppc_md.get_rtc_time)
1209 return -ENODEV;
1210
1211 pdev = platform_device_register_data(NULL, "rtc-generic", -1,
1212 &rtc_generic_ops,
1213 sizeof(rtc_generic_ops));
1214
1215 return PTR_ERR_OR_ZERO(pdev);
1216}
1217
1218device_initcall(rtc_init);
1219#endif
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Common time routines among all ppc machines.
4 *
5 * Written by Cort Dougan (cort@cs.nmt.edu) to merge
6 * Paul Mackerras' version and mine for PReP and Pmac.
7 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
8 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
9 *
10 * First round of bugfixes by Gabriel Paubert (paubert@iram.es)
11 * to make clock more stable (2.4.0-test5). The only thing
12 * that this code assumes is that the timebases have been synchronized
13 * by firmware on SMP and are never stopped (never do sleep
14 * on SMP then, nap and doze are OK).
15 *
16 * Speeded up do_gettimeofday by getting rid of references to
17 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
18 *
19 * TODO (not necessarily in this file):
20 * - improve precision and reproducibility of timebase frequency
21 * measurement at boot time.
22 * - for astronomical applications: add a new function to get
23 * non ambiguous timestamps even around leap seconds. This needs
24 * a new timestamp format and a good name.
25 *
26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
27 * "A Kernel Model for Precision Timekeeping" by Dave Mills
28 */
29
30#include <linux/errno.h>
31#include <linux/export.h>
32#include <linux/sched.h>
33#include <linux/sched/clock.h>
34#include <linux/kernel.h>
35#include <linux/param.h>
36#include <linux/string.h>
37#include <linux/mm.h>
38#include <linux/interrupt.h>
39#include <linux/timex.h>
40#include <linux/kernel_stat.h>
41#include <linux/time.h>
42#include <linux/init.h>
43#include <linux/profile.h>
44#include <linux/cpu.h>
45#include <linux/security.h>
46#include <linux/percpu.h>
47#include <linux/rtc.h>
48#include <linux/jiffies.h>
49#include <linux/posix-timers.h>
50#include <linux/irq.h>
51#include <linux/delay.h>
52#include <linux/irq_work.h>
53#include <linux/clk-provider.h>
54#include <linux/suspend.h>
55#include <linux/sched/cputime.h>
56#include <linux/processor.h>
57#include <asm/trace.h>
58
59#include <asm/io.h>
60#include <asm/nvram.h>
61#include <asm/cache.h>
62#include <asm/machdep.h>
63#include <linux/uaccess.h>
64#include <asm/time.h>
65#include <asm/prom.h>
66#include <asm/irq.h>
67#include <asm/div64.h>
68#include <asm/smp.h>
69#include <asm/vdso_datapage.h>
70#include <asm/firmware.h>
71#include <asm/asm-prototypes.h>
72
73/* powerpc clocksource/clockevent code */
74
75#include <linux/clockchips.h>
76#include <linux/timekeeper_internal.h>
77
78static u64 rtc_read(struct clocksource *);
79static struct clocksource clocksource_rtc = {
80 .name = "rtc",
81 .rating = 400,
82 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
83 .mask = CLOCKSOURCE_MASK(64),
84 .read = rtc_read,
85};
86
87static u64 timebase_read(struct clocksource *);
88static struct clocksource clocksource_timebase = {
89 .name = "timebase",
90 .rating = 400,
91 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
92 .mask = CLOCKSOURCE_MASK(64),
93 .read = timebase_read,
94};
95
96#define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF
97u64 decrementer_max = DECREMENTER_DEFAULT_MAX;
98
99static int decrementer_set_next_event(unsigned long evt,
100 struct clock_event_device *dev);
101static int decrementer_shutdown(struct clock_event_device *evt);
102
103struct clock_event_device decrementer_clockevent = {
104 .name = "decrementer",
105 .rating = 200,
106 .irq = 0,
107 .set_next_event = decrementer_set_next_event,
108 .set_state_oneshot_stopped = decrementer_shutdown,
109 .set_state_shutdown = decrementer_shutdown,
110 .tick_resume = decrementer_shutdown,
111 .features = CLOCK_EVT_FEAT_ONESHOT |
112 CLOCK_EVT_FEAT_C3STOP,
113};
114EXPORT_SYMBOL(decrementer_clockevent);
115
116DEFINE_PER_CPU(u64, decrementers_next_tb);
117static DEFINE_PER_CPU(struct clock_event_device, decrementers);
118
119#define XSEC_PER_SEC (1024*1024)
120
121#ifdef CONFIG_PPC64
122#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
123#else
124/* compute ((xsec << 12) * max) >> 32 */
125#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
126#endif
127
128unsigned long tb_ticks_per_jiffy;
129unsigned long tb_ticks_per_usec = 100; /* sane default */
130EXPORT_SYMBOL(tb_ticks_per_usec);
131unsigned long tb_ticks_per_sec;
132EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
133
134DEFINE_SPINLOCK(rtc_lock);
135EXPORT_SYMBOL_GPL(rtc_lock);
136
137static u64 tb_to_ns_scale __read_mostly;
138static unsigned tb_to_ns_shift __read_mostly;
139static u64 boot_tb __read_mostly;
140
141extern struct timezone sys_tz;
142static long timezone_offset;
143
144unsigned long ppc_proc_freq;
145EXPORT_SYMBOL_GPL(ppc_proc_freq);
146unsigned long ppc_tb_freq;
147EXPORT_SYMBOL_GPL(ppc_tb_freq);
148
149bool tb_invalid;
150
151#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
152/*
153 * Factor for converting from cputime_t (timebase ticks) to
154 * microseconds. This is stored as 0.64 fixed-point binary fraction.
155 */
156u64 __cputime_usec_factor;
157EXPORT_SYMBOL(__cputime_usec_factor);
158
159#ifdef CONFIG_PPC_SPLPAR
160void (*dtl_consumer)(struct dtl_entry *, u64);
161#endif
162
163static void calc_cputime_factors(void)
164{
165 struct div_result res;
166
167 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
168 __cputime_usec_factor = res.result_low;
169}
170
171/*
172 * Read the SPURR on systems that have it, otherwise the PURR,
173 * or if that doesn't exist return the timebase value passed in.
174 */
175static inline unsigned long read_spurr(unsigned long tb)
176{
177 if (cpu_has_feature(CPU_FTR_SPURR))
178 return mfspr(SPRN_SPURR);
179 if (cpu_has_feature(CPU_FTR_PURR))
180 return mfspr(SPRN_PURR);
181 return tb;
182}
183
184#ifdef CONFIG_PPC_SPLPAR
185
186/*
187 * Scan the dispatch trace log and count up the stolen time.
188 * Should be called with interrupts disabled.
189 */
190static u64 scan_dispatch_log(u64 stop_tb)
191{
192 u64 i = local_paca->dtl_ridx;
193 struct dtl_entry *dtl = local_paca->dtl_curr;
194 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
195 struct lppaca *vpa = local_paca->lppaca_ptr;
196 u64 tb_delta;
197 u64 stolen = 0;
198 u64 dtb;
199
200 if (!dtl)
201 return 0;
202
203 if (i == be64_to_cpu(vpa->dtl_idx))
204 return 0;
205 while (i < be64_to_cpu(vpa->dtl_idx)) {
206 dtb = be64_to_cpu(dtl->timebase);
207 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) +
208 be32_to_cpu(dtl->ready_to_enqueue_time);
209 barrier();
210 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) {
211 /* buffer has overflowed */
212 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG;
213 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
214 continue;
215 }
216 if (dtb > stop_tb)
217 break;
218 if (dtl_consumer)
219 dtl_consumer(dtl, i);
220 stolen += tb_delta;
221 ++i;
222 ++dtl;
223 if (dtl == dtl_end)
224 dtl = local_paca->dispatch_log;
225 }
226 local_paca->dtl_ridx = i;
227 local_paca->dtl_curr = dtl;
228 return stolen;
229}
230
231/*
232 * Accumulate stolen time by scanning the dispatch trace log.
233 * Called on entry from user mode.
234 */
235void accumulate_stolen_time(void)
236{
237 u64 sst, ust;
238 unsigned long save_irq_soft_mask = irq_soft_mask_return();
239 struct cpu_accounting_data *acct = &local_paca->accounting;
240
241 /* We are called early in the exception entry, before
242 * soft/hard_enabled are sync'ed to the expected state
243 * for the exception. We are hard disabled but the PACA
244 * needs to reflect that so various debug stuff doesn't
245 * complain
246 */
247 irq_soft_mask_set(IRQS_DISABLED);
248
249 sst = scan_dispatch_log(acct->starttime_user);
250 ust = scan_dispatch_log(acct->starttime);
251 acct->stime -= sst;
252 acct->utime -= ust;
253 acct->steal_time += ust + sst;
254
255 irq_soft_mask_set(save_irq_soft_mask);
256}
257
258static inline u64 calculate_stolen_time(u64 stop_tb)
259{
260 if (!firmware_has_feature(FW_FEATURE_SPLPAR))
261 return 0;
262
263 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx))
264 return scan_dispatch_log(stop_tb);
265
266 return 0;
267}
268
269#else /* CONFIG_PPC_SPLPAR */
270static inline u64 calculate_stolen_time(u64 stop_tb)
271{
272 return 0;
273}
274
275#endif /* CONFIG_PPC_SPLPAR */
276
277/*
278 * Account time for a transition between system, hard irq
279 * or soft irq state.
280 */
281static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct,
282 unsigned long now, unsigned long stime)
283{
284 unsigned long stime_scaled = 0;
285#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
286 unsigned long nowscaled, deltascaled;
287 unsigned long utime, utime_scaled;
288
289 nowscaled = read_spurr(now);
290 deltascaled = nowscaled - acct->startspurr;
291 acct->startspurr = nowscaled;
292 utime = acct->utime - acct->utime_sspurr;
293 acct->utime_sspurr = acct->utime;
294
295 /*
296 * Because we don't read the SPURR on every kernel entry/exit,
297 * deltascaled includes both user and system SPURR ticks.
298 * Apportion these ticks to system SPURR ticks and user
299 * SPURR ticks in the same ratio as the system time (delta)
300 * and user time (udelta) values obtained from the timebase
301 * over the same interval. The system ticks get accounted here;
302 * the user ticks get saved up in paca->user_time_scaled to be
303 * used by account_process_tick.
304 */
305 stime_scaled = stime;
306 utime_scaled = utime;
307 if (deltascaled != stime + utime) {
308 if (utime) {
309 stime_scaled = deltascaled * stime / (stime + utime);
310 utime_scaled = deltascaled - stime_scaled;
311 } else {
312 stime_scaled = deltascaled;
313 }
314 }
315 acct->utime_scaled += utime_scaled;
316#endif
317
318 return stime_scaled;
319}
320
321static unsigned long vtime_delta(struct task_struct *tsk,
322 unsigned long *stime_scaled,
323 unsigned long *steal_time)
324{
325 unsigned long now, stime;
326 struct cpu_accounting_data *acct = get_accounting(tsk);
327
328 WARN_ON_ONCE(!irqs_disabled());
329
330 now = mftb();
331 stime = now - acct->starttime;
332 acct->starttime = now;
333
334 *stime_scaled = vtime_delta_scaled(acct, now, stime);
335
336 *steal_time = calculate_stolen_time(now);
337
338 return stime;
339}
340
341void vtime_account_system(struct task_struct *tsk)
342{
343 unsigned long stime, stime_scaled, steal_time;
344 struct cpu_accounting_data *acct = get_accounting(tsk);
345
346 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
347
348 stime -= min(stime, steal_time);
349 acct->steal_time += steal_time;
350
351 if ((tsk->flags & PF_VCPU) && !irq_count()) {
352 acct->gtime += stime;
353#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
354 acct->utime_scaled += stime_scaled;
355#endif
356 } else {
357 if (hardirq_count())
358 acct->hardirq_time += stime;
359 else if (in_serving_softirq())
360 acct->softirq_time += stime;
361 else
362 acct->stime += stime;
363
364#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
365 acct->stime_scaled += stime_scaled;
366#endif
367 }
368}
369EXPORT_SYMBOL_GPL(vtime_account_system);
370
371void vtime_account_idle(struct task_struct *tsk)
372{
373 unsigned long stime, stime_scaled, steal_time;
374 struct cpu_accounting_data *acct = get_accounting(tsk);
375
376 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
377 acct->idle_time += stime + steal_time;
378}
379
380static void vtime_flush_scaled(struct task_struct *tsk,
381 struct cpu_accounting_data *acct)
382{
383#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
384 if (acct->utime_scaled)
385 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
386 if (acct->stime_scaled)
387 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
388
389 acct->utime_scaled = 0;
390 acct->utime_sspurr = 0;
391 acct->stime_scaled = 0;
392#endif
393}
394
395/*
396 * Account the whole cputime accumulated in the paca
397 * Must be called with interrupts disabled.
398 * Assumes that vtime_account_system/idle() has been called
399 * recently (i.e. since the last entry from usermode) so that
400 * get_paca()->user_time_scaled is up to date.
401 */
402void vtime_flush(struct task_struct *tsk)
403{
404 struct cpu_accounting_data *acct = get_accounting(tsk);
405
406 if (acct->utime)
407 account_user_time(tsk, cputime_to_nsecs(acct->utime));
408
409 if (acct->gtime)
410 account_guest_time(tsk, cputime_to_nsecs(acct->gtime));
411
412 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) {
413 account_steal_time(cputime_to_nsecs(acct->steal_time));
414 acct->steal_time = 0;
415 }
416
417 if (acct->idle_time)
418 account_idle_time(cputime_to_nsecs(acct->idle_time));
419
420 if (acct->stime)
421 account_system_index_time(tsk, cputime_to_nsecs(acct->stime),
422 CPUTIME_SYSTEM);
423
424 if (acct->hardirq_time)
425 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time),
426 CPUTIME_IRQ);
427 if (acct->softirq_time)
428 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time),
429 CPUTIME_SOFTIRQ);
430
431 vtime_flush_scaled(tsk, acct);
432
433 acct->utime = 0;
434 acct->gtime = 0;
435 acct->idle_time = 0;
436 acct->stime = 0;
437 acct->hardirq_time = 0;
438 acct->softirq_time = 0;
439}
440
441#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
442#define calc_cputime_factors()
443#endif
444
445void __delay(unsigned long loops)
446{
447 unsigned long start;
448 int diff;
449
450 spin_begin();
451 if (__USE_RTC()) {
452 start = get_rtcl();
453 do {
454 /* the RTCL register wraps at 1000000000 */
455 diff = get_rtcl() - start;
456 if (diff < 0)
457 diff += 1000000000;
458 spin_cpu_relax();
459 } while (diff < loops);
460 } else if (tb_invalid) {
461 /*
462 * TB is in error state and isn't ticking anymore.
463 * HMI handler was unable to recover from TB error.
464 * Return immediately, so that kernel won't get stuck here.
465 */
466 spin_cpu_relax();
467 } else {
468 start = get_tbl();
469 while (get_tbl() - start < loops)
470 spin_cpu_relax();
471 }
472 spin_end();
473}
474EXPORT_SYMBOL(__delay);
475
476void udelay(unsigned long usecs)
477{
478 __delay(tb_ticks_per_usec * usecs);
479}
480EXPORT_SYMBOL(udelay);
481
482#ifdef CONFIG_SMP
483unsigned long profile_pc(struct pt_regs *regs)
484{
485 unsigned long pc = instruction_pointer(regs);
486
487 if (in_lock_functions(pc))
488 return regs->link;
489
490 return pc;
491}
492EXPORT_SYMBOL(profile_pc);
493#endif
494
495#ifdef CONFIG_IRQ_WORK
496
497/*
498 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
499 */
500#ifdef CONFIG_PPC64
501static inline unsigned long test_irq_work_pending(void)
502{
503 unsigned long x;
504
505 asm volatile("lbz %0,%1(13)"
506 : "=r" (x)
507 : "i" (offsetof(struct paca_struct, irq_work_pending)));
508 return x;
509}
510
511static inline void set_irq_work_pending_flag(void)
512{
513 asm volatile("stb %0,%1(13)" : :
514 "r" (1),
515 "i" (offsetof(struct paca_struct, irq_work_pending)));
516}
517
518static inline void clear_irq_work_pending(void)
519{
520 asm volatile("stb %0,%1(13)" : :
521 "r" (0),
522 "i" (offsetof(struct paca_struct, irq_work_pending)));
523}
524
525void arch_irq_work_raise(void)
526{
527 preempt_disable();
528 set_irq_work_pending_flag();
529 /*
530 * Non-nmi code running with interrupts disabled will replay
531 * irq_happened before it re-enables interrupts, so setthe
532 * decrementer there instead of causing a hardware exception
533 * which would immediately hit the masked interrupt handler
534 * and have the net effect of setting the decrementer in
535 * irq_happened.
536 *
537 * NMI interrupts can not check this when they return, so the
538 * decrementer hardware exception is raised, which will fire
539 * when interrupts are next enabled.
540 *
541 * BookE does not support this yet, it must audit all NMI
542 * interrupt handlers to ensure they call nmi_enter() so this
543 * check would be correct.
544 */
545 if (IS_ENABLED(CONFIG_BOOKE) || !irqs_disabled() || in_nmi()) {
546 set_dec(1);
547 } else {
548 hard_irq_disable();
549 local_paca->irq_happened |= PACA_IRQ_DEC;
550 }
551 preempt_enable();
552}
553
554#else /* 32-bit */
555
556DEFINE_PER_CPU(u8, irq_work_pending);
557
558#define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1)
559#define test_irq_work_pending() __this_cpu_read(irq_work_pending)
560#define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
561
562void arch_irq_work_raise(void)
563{
564 preempt_disable();
565 set_irq_work_pending_flag();
566 set_dec(1);
567 preempt_enable();
568}
569
570#endif /* 32 vs 64 bit */
571
572#else /* CONFIG_IRQ_WORK */
573
574#define test_irq_work_pending() 0
575#define clear_irq_work_pending()
576
577#endif /* CONFIG_IRQ_WORK */
578
579/*
580 * timer_interrupt - gets called when the decrementer overflows,
581 * with interrupts disabled.
582 */
583void timer_interrupt(struct pt_regs *regs)
584{
585 struct clock_event_device *evt = this_cpu_ptr(&decrementers);
586 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
587 struct pt_regs *old_regs;
588 u64 now;
589
590 /* Some implementations of hotplug will get timer interrupts while
591 * offline, just ignore these and we also need to set
592 * decrementers_next_tb as MAX to make sure __check_irq_replay
593 * don't replay timer interrupt when return, otherwise we'll trap
594 * here infinitely :(
595 */
596 if (unlikely(!cpu_online(smp_processor_id()))) {
597 *next_tb = ~(u64)0;
598 set_dec(decrementer_max);
599 return;
600 }
601
602 /* Ensure a positive value is written to the decrementer, or else
603 * some CPUs will continue to take decrementer exceptions. When the
604 * PPC_WATCHDOG (decrementer based) is configured, keep this at most
605 * 31 bits, which is about 4 seconds on most systems, which gives
606 * the watchdog a chance of catching timer interrupt hard lockups.
607 */
608 if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
609 set_dec(0x7fffffff);
610 else
611 set_dec(decrementer_max);
612
613 /* Conditionally hard-enable interrupts now that the DEC has been
614 * bumped to its maximum value
615 */
616 may_hard_irq_enable();
617
618
619#if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC)
620 if (atomic_read(&ppc_n_lost_interrupts) != 0)
621 do_IRQ(regs);
622#endif
623
624 old_regs = set_irq_regs(regs);
625 irq_enter();
626 trace_timer_interrupt_entry(regs);
627
628 if (test_irq_work_pending()) {
629 clear_irq_work_pending();
630 irq_work_run();
631 }
632
633 now = get_tb_or_rtc();
634 if (now >= *next_tb) {
635 *next_tb = ~(u64)0;
636 if (evt->event_handler)
637 evt->event_handler(evt);
638 __this_cpu_inc(irq_stat.timer_irqs_event);
639 } else {
640 now = *next_tb - now;
641 if (now <= decrementer_max)
642 set_dec(now);
643 /* We may have raced with new irq work */
644 if (test_irq_work_pending())
645 set_dec(1);
646 __this_cpu_inc(irq_stat.timer_irqs_others);
647 }
648
649 trace_timer_interrupt_exit(regs);
650 irq_exit();
651 set_irq_regs(old_regs);
652}
653EXPORT_SYMBOL(timer_interrupt);
654
655#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
656void timer_broadcast_interrupt(void)
657{
658 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
659
660 *next_tb = ~(u64)0;
661 tick_receive_broadcast();
662 __this_cpu_inc(irq_stat.broadcast_irqs_event);
663}
664#endif
665
666/*
667 * Hypervisor decrementer interrupts shouldn't occur but are sometimes
668 * left pending on exit from a KVM guest. We don't need to do anything
669 * to clear them, as they are edge-triggered.
670 */
671void hdec_interrupt(struct pt_regs *regs)
672{
673}
674
675#ifdef CONFIG_SUSPEND
676static void generic_suspend_disable_irqs(void)
677{
678 /* Disable the decrementer, so that it doesn't interfere
679 * with suspending.
680 */
681
682 set_dec(decrementer_max);
683 local_irq_disable();
684 set_dec(decrementer_max);
685}
686
687static void generic_suspend_enable_irqs(void)
688{
689 local_irq_enable();
690}
691
692/* Overrides the weak version in kernel/power/main.c */
693void arch_suspend_disable_irqs(void)
694{
695 if (ppc_md.suspend_disable_irqs)
696 ppc_md.suspend_disable_irqs();
697 generic_suspend_disable_irqs();
698}
699
700/* Overrides the weak version in kernel/power/main.c */
701void arch_suspend_enable_irqs(void)
702{
703 generic_suspend_enable_irqs();
704 if (ppc_md.suspend_enable_irqs)
705 ppc_md.suspend_enable_irqs();
706}
707#endif
708
709unsigned long long tb_to_ns(unsigned long long ticks)
710{
711 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift;
712}
713EXPORT_SYMBOL_GPL(tb_to_ns);
714
715/*
716 * Scheduler clock - returns current time in nanosec units.
717 *
718 * Note: mulhdu(a, b) (multiply high double unsigned) returns
719 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
720 * are 64-bit unsigned numbers.
721 */
722notrace unsigned long long sched_clock(void)
723{
724 if (__USE_RTC())
725 return get_rtc();
726 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
727}
728
729
730#ifdef CONFIG_PPC_PSERIES
731
732/*
733 * Running clock - attempts to give a view of time passing for a virtualised
734 * kernels.
735 * Uses the VTB register if available otherwise a next best guess.
736 */
737unsigned long long running_clock(void)
738{
739 /*
740 * Don't read the VTB as a host since KVM does not switch in host
741 * timebase into the VTB when it takes a guest off the CPU, reading the
742 * VTB would result in reading 'last switched out' guest VTB.
743 *
744 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
745 * would be unsafe to rely only on the #ifdef above.
746 */
747 if (firmware_has_feature(FW_FEATURE_LPAR) &&
748 cpu_has_feature(CPU_FTR_ARCH_207S))
749 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
750
751 /*
752 * This is a next best approximation without a VTB.
753 * On a host which is running bare metal there should never be any stolen
754 * time and on a host which doesn't do any virtualisation TB *should* equal
755 * VTB so it makes no difference anyway.
756 */
757 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL];
758}
759#endif
760
761static int __init get_freq(char *name, int cells, unsigned long *val)
762{
763 struct device_node *cpu;
764 const __be32 *fp;
765 int found = 0;
766
767 /* The cpu node should have timebase and clock frequency properties */
768 cpu = of_find_node_by_type(NULL, "cpu");
769
770 if (cpu) {
771 fp = of_get_property(cpu, name, NULL);
772 if (fp) {
773 found = 1;
774 *val = of_read_ulong(fp, cells);
775 }
776
777 of_node_put(cpu);
778 }
779
780 return found;
781}
782
783static void start_cpu_decrementer(void)
784{
785#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
786 unsigned int tcr;
787
788 /* Clear any pending timer interrupts */
789 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
790
791 tcr = mfspr(SPRN_TCR);
792 /*
793 * The watchdog may have already been enabled by u-boot. So leave
794 * TRC[WP] (Watchdog Period) alone.
795 */
796 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */
797 tcr |= TCR_DIE; /* Enable decrementer */
798 mtspr(SPRN_TCR, tcr);
799#endif
800}
801
802void __init generic_calibrate_decr(void)
803{
804 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
805
806 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
807 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
808
809 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
810 "(not found)\n");
811 }
812
813 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
814
815 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
816 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
817
818 printk(KERN_ERR "WARNING: Estimating processor frequency "
819 "(not found)\n");
820 }
821}
822
823int update_persistent_clock64(struct timespec64 now)
824{
825 struct rtc_time tm;
826
827 if (!ppc_md.set_rtc_time)
828 return -ENODEV;
829
830 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm);
831
832 return ppc_md.set_rtc_time(&tm);
833}
834
835static void __read_persistent_clock(struct timespec64 *ts)
836{
837 struct rtc_time tm;
838 static int first = 1;
839
840 ts->tv_nsec = 0;
841 /* XXX this is a litle fragile but will work okay in the short term */
842 if (first) {
843 first = 0;
844 if (ppc_md.time_init)
845 timezone_offset = ppc_md.time_init();
846
847 /* get_boot_time() isn't guaranteed to be safe to call late */
848 if (ppc_md.get_boot_time) {
849 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
850 return;
851 }
852 }
853 if (!ppc_md.get_rtc_time) {
854 ts->tv_sec = 0;
855 return;
856 }
857 ppc_md.get_rtc_time(&tm);
858
859 ts->tv_sec = rtc_tm_to_time64(&tm);
860}
861
862void read_persistent_clock64(struct timespec64 *ts)
863{
864 __read_persistent_clock(ts);
865
866 /* Sanitize it in case real time clock is set below EPOCH */
867 if (ts->tv_sec < 0) {
868 ts->tv_sec = 0;
869 ts->tv_nsec = 0;
870 }
871
872}
873
874/* clocksource code */
875static notrace u64 rtc_read(struct clocksource *cs)
876{
877 return (u64)get_rtc();
878}
879
880static notrace u64 timebase_read(struct clocksource *cs)
881{
882 return (u64)get_tb();
883}
884
885
886void update_vsyscall(struct timekeeper *tk)
887{
888 struct timespec xt;
889 struct clocksource *clock = tk->tkr_mono.clock;
890 u32 mult = tk->tkr_mono.mult;
891 u32 shift = tk->tkr_mono.shift;
892 u64 cycle_last = tk->tkr_mono.cycle_last;
893 u64 new_tb_to_xs, new_stamp_xsec;
894 u64 frac_sec;
895
896 if (clock != &clocksource_timebase)
897 return;
898
899 xt.tv_sec = tk->xtime_sec;
900 xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
901
902 /* Make userspace gettimeofday spin until we're done. */
903 ++vdso_data->tb_update_count;
904 smp_mb();
905
906 /*
907 * This computes ((2^20 / 1e9) * mult) >> shift as a
908 * 0.64 fixed-point fraction.
909 * The computation in the else clause below won't overflow
910 * (as long as the timebase frequency is >= 1.049 MHz)
911 * but loses precision because we lose the low bits of the constant
912 * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9.
913 * For a shift of 24 the error is about 0.5e-9, or about 0.5ns
914 * over a second. (Shift values are usually 22, 23 or 24.)
915 * For high frequency clocks such as the 512MHz timebase clock
916 * on POWER[6789], the mult value is small (e.g. 32768000)
917 * and so we can shift the constant by 16 initially
918 * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the
919 * remaining shifts after the multiplication, which gives a
920 * more accurate result (e.g. with mult = 32768000, shift = 24,
921 * the error is only about 1.2e-12, or 0.7ns over 10 minutes).
922 */
923 if (mult <= 62500000 && clock->shift >= 16)
924 new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16);
925 else
926 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
927
928 /*
929 * Compute the fractional second in units of 2^-32 seconds.
930 * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift
931 * in nanoseconds, so multiplying that by 2^32 / 1e9 gives
932 * it in units of 2^-32 seconds.
933 * We assume shift <= 32 because clocks_calc_mult_shift()
934 * generates shift values in the range 0 - 32.
935 */
936 frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift);
937 do_div(frac_sec, NSEC_PER_SEC);
938
939 /*
940 * Work out new stamp_xsec value for any legacy users of systemcfg.
941 * stamp_xsec is in units of 2^-20 seconds.
942 */
943 new_stamp_xsec = frac_sec >> 12;
944 new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC;
945
946 /*
947 * tb_update_count is used to allow the userspace gettimeofday code
948 * to assure itself that it sees a consistent view of the tb_to_xs and
949 * stamp_xsec variables. It reads the tb_update_count, then reads
950 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
951 * the two values of tb_update_count match and are even then the
952 * tb_to_xs and stamp_xsec values are consistent. If not, then it
953 * loops back and reads them again until this criteria is met.
954 */
955 vdso_data->tb_orig_stamp = cycle_last;
956 vdso_data->stamp_xsec = new_stamp_xsec;
957 vdso_data->tb_to_xs = new_tb_to_xs;
958 vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
959 vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
960 vdso_data->stamp_xtime = xt;
961 vdso_data->stamp_sec_fraction = frac_sec;
962 smp_wmb();
963 ++(vdso_data->tb_update_count);
964}
965
966void update_vsyscall_tz(void)
967{
968 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
969 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
970}
971
972static void __init clocksource_init(void)
973{
974 struct clocksource *clock;
975
976 if (__USE_RTC())
977 clock = &clocksource_rtc;
978 else
979 clock = &clocksource_timebase;
980
981 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
982 printk(KERN_ERR "clocksource: %s is already registered\n",
983 clock->name);
984 return;
985 }
986
987 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
988 clock->name, clock->mult, clock->shift);
989}
990
991static int decrementer_set_next_event(unsigned long evt,
992 struct clock_event_device *dev)
993{
994 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt);
995 set_dec(evt);
996
997 /* We may have raced with new irq work */
998 if (test_irq_work_pending())
999 set_dec(1);
1000
1001 return 0;
1002}
1003
1004static int decrementer_shutdown(struct clock_event_device *dev)
1005{
1006 decrementer_set_next_event(decrementer_max, dev);
1007 return 0;
1008}
1009
1010static void register_decrementer_clockevent(int cpu)
1011{
1012 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
1013
1014 *dec = decrementer_clockevent;
1015 dec->cpumask = cpumask_of(cpu);
1016
1017 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max);
1018
1019 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
1020 dec->name, dec->mult, dec->shift, cpu);
1021
1022 /* Set values for KVM, see kvm_emulate_dec() */
1023 decrementer_clockevent.mult = dec->mult;
1024 decrementer_clockevent.shift = dec->shift;
1025}
1026
1027static void enable_large_decrementer(void)
1028{
1029 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1030 return;
1031
1032 if (decrementer_max <= DECREMENTER_DEFAULT_MAX)
1033 return;
1034
1035 /*
1036 * If we're running as the hypervisor we need to enable the LD manually
1037 * otherwise firmware should have done it for us.
1038 */
1039 if (cpu_has_feature(CPU_FTR_HVMODE))
1040 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD);
1041}
1042
1043static void __init set_decrementer_max(void)
1044{
1045 struct device_node *cpu;
1046 u32 bits = 32;
1047
1048 /* Prior to ISAv3 the decrementer is always 32 bit */
1049 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1050 return;
1051
1052 cpu = of_find_node_by_type(NULL, "cpu");
1053
1054 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) {
1055 if (bits > 64 || bits < 32) {
1056 pr_warn("time_init: firmware supplied invalid ibm,dec-bits");
1057 bits = 32;
1058 }
1059
1060 /* calculate the signed maximum given this many bits */
1061 decrementer_max = (1ul << (bits - 1)) - 1;
1062 }
1063
1064 of_node_put(cpu);
1065
1066 pr_info("time_init: %u bit decrementer (max: %llx)\n",
1067 bits, decrementer_max);
1068}
1069
1070static void __init init_decrementer_clockevent(void)
1071{
1072 register_decrementer_clockevent(smp_processor_id());
1073}
1074
1075void secondary_cpu_time_init(void)
1076{
1077 /* Enable and test the large decrementer for this cpu */
1078 enable_large_decrementer();
1079
1080 /* Start the decrementer on CPUs that have manual control
1081 * such as BookE
1082 */
1083 start_cpu_decrementer();
1084
1085 /* FIME: Should make unrelatred change to move snapshot_timebase
1086 * call here ! */
1087 register_decrementer_clockevent(smp_processor_id());
1088}
1089
1090/* This function is only called on the boot processor */
1091void __init time_init(void)
1092{
1093 struct div_result res;
1094 u64 scale;
1095 unsigned shift;
1096
1097 if (__USE_RTC()) {
1098 /* 601 processor: dec counts down by 128 every 128ns */
1099 ppc_tb_freq = 1000000000;
1100 } else {
1101 /* Normal PowerPC with timebase register */
1102 ppc_md.calibrate_decr();
1103 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
1104 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
1105 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
1106 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
1107 }
1108
1109 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
1110 tb_ticks_per_sec = ppc_tb_freq;
1111 tb_ticks_per_usec = ppc_tb_freq / 1000000;
1112 calc_cputime_factors();
1113
1114 /*
1115 * Compute scale factor for sched_clock.
1116 * The calibrate_decr() function has set tb_ticks_per_sec,
1117 * which is the timebase frequency.
1118 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
1119 * the 128-bit result as a 64.64 fixed-point number.
1120 * We then shift that number right until it is less than 1.0,
1121 * giving us the scale factor and shift count to use in
1122 * sched_clock().
1123 */
1124 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
1125 scale = res.result_low;
1126 for (shift = 0; res.result_high != 0; ++shift) {
1127 scale = (scale >> 1) | (res.result_high << 63);
1128 res.result_high >>= 1;
1129 }
1130 tb_to_ns_scale = scale;
1131 tb_to_ns_shift = shift;
1132 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
1133 boot_tb = get_tb_or_rtc();
1134
1135 /* If platform provided a timezone (pmac), we correct the time */
1136 if (timezone_offset) {
1137 sys_tz.tz_minuteswest = -timezone_offset / 60;
1138 sys_tz.tz_dsttime = 0;
1139 }
1140
1141 vdso_data->tb_update_count = 0;
1142 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
1143
1144 /* initialise and enable the large decrementer (if we have one) */
1145 set_decrementer_max();
1146 enable_large_decrementer();
1147
1148 /* Start the decrementer on CPUs that have manual control
1149 * such as BookE
1150 */
1151 start_cpu_decrementer();
1152
1153 /* Register the clocksource */
1154 clocksource_init();
1155
1156 init_decrementer_clockevent();
1157 tick_setup_hrtimer_broadcast();
1158
1159#ifdef CONFIG_COMMON_CLK
1160 of_clk_init(NULL);
1161#endif
1162}
1163
1164/*
1165 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1166 * result.
1167 */
1168void div128_by_32(u64 dividend_high, u64 dividend_low,
1169 unsigned divisor, struct div_result *dr)
1170{
1171 unsigned long a, b, c, d;
1172 unsigned long w, x, y, z;
1173 u64 ra, rb, rc;
1174
1175 a = dividend_high >> 32;
1176 b = dividend_high & 0xffffffff;
1177 c = dividend_low >> 32;
1178 d = dividend_low & 0xffffffff;
1179
1180 w = a / divisor;
1181 ra = ((u64)(a - (w * divisor)) << 32) + b;
1182
1183 rb = ((u64) do_div(ra, divisor) << 32) + c;
1184 x = ra;
1185
1186 rc = ((u64) do_div(rb, divisor) << 32) + d;
1187 y = rb;
1188
1189 do_div(rc, divisor);
1190 z = rc;
1191
1192 dr->result_high = ((u64)w << 32) + x;
1193 dr->result_low = ((u64)y << 32) + z;
1194
1195}
1196
1197/* We don't need to calibrate delay, we use the CPU timebase for that */
1198void calibrate_delay(void)
1199{
1200 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1201 * as the number of __delay(1) in a jiffy, so make it so
1202 */
1203 loops_per_jiffy = tb_ticks_per_jiffy;
1204}
1205
1206#if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
1207static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
1208{
1209 ppc_md.get_rtc_time(tm);
1210 return 0;
1211}
1212
1213static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
1214{
1215 if (!ppc_md.set_rtc_time)
1216 return -EOPNOTSUPP;
1217
1218 if (ppc_md.set_rtc_time(tm) < 0)
1219 return -EOPNOTSUPP;
1220
1221 return 0;
1222}
1223
1224static const struct rtc_class_ops rtc_generic_ops = {
1225 .read_time = rtc_generic_get_time,
1226 .set_time = rtc_generic_set_time,
1227};
1228
1229static int __init rtc_init(void)
1230{
1231 struct platform_device *pdev;
1232
1233 if (!ppc_md.get_rtc_time)
1234 return -ENODEV;
1235
1236 pdev = platform_device_register_data(NULL, "rtc-generic", -1,
1237 &rtc_generic_ops,
1238 sizeof(rtc_generic_ops));
1239
1240 return PTR_ERR_OR_ZERO(pdev);
1241}
1242
1243device_initcall(rtc_init);
1244#endif