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