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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/smp.c
4 *
5 * Copyright (C) 2002 ARM Limited, All Rights Reserved.
6 */
7#include <linux/module.h>
8#include <linux/delay.h>
9#include <linux/init.h>
10#include <linux/spinlock.h>
11#include <linux/sched/mm.h>
12#include <linux/sched/hotplug.h>
13#include <linux/sched/task_stack.h>
14#include <linux/interrupt.h>
15#include <linux/cache.h>
16#include <linux/profile.h>
17#include <linux/errno.h>
18#include <linux/mm.h>
19#include <linux/err.h>
20#include <linux/cpu.h>
21#include <linux/seq_file.h>
22#include <linux/irq.h>
23#include <linux/nmi.h>
24#include <linux/percpu.h>
25#include <linux/clockchips.h>
26#include <linux/completion.h>
27#include <linux/cpufreq.h>
28#include <linux/irq_work.h>
29
30#include <linux/atomic.h>
31#include <asm/bugs.h>
32#include <asm/smp.h>
33#include <asm/cacheflush.h>
34#include <asm/cpu.h>
35#include <asm/cputype.h>
36#include <asm/exception.h>
37#include <asm/idmap.h>
38#include <asm/topology.h>
39#include <asm/mmu_context.h>
40#include <asm/procinfo.h>
41#include <asm/processor.h>
42#include <asm/sections.h>
43#include <asm/tlbflush.h>
44#include <asm/ptrace.h>
45#include <asm/smp_plat.h>
46#include <asm/virt.h>
47#include <asm/mach/arch.h>
48#include <asm/mpu.h>
49
50#define CREATE_TRACE_POINTS
51#include <trace/events/ipi.h>
52
53/*
54 * as from 2.5, kernels no longer have an init_tasks structure
55 * so we need some other way of telling a new secondary core
56 * where to place its SVC stack
57 */
58struct secondary_data secondary_data;
59
60enum ipi_msg_type {
61 IPI_WAKEUP,
62 IPI_TIMER,
63 IPI_RESCHEDULE,
64 IPI_CALL_FUNC,
65 IPI_CPU_STOP,
66 IPI_IRQ_WORK,
67 IPI_COMPLETION,
68 /*
69 * CPU_BACKTRACE is special and not included in NR_IPI
70 * or tracable with trace_ipi_*
71 */
72 IPI_CPU_BACKTRACE,
73 /*
74 * SGI8-15 can be reserved by secure firmware, and thus may
75 * not be usable by the kernel. Please keep the above limited
76 * to at most 8 entries.
77 */
78};
79
80static DECLARE_COMPLETION(cpu_running);
81
82static struct smp_operations smp_ops __ro_after_init;
83
84void __init smp_set_ops(const struct smp_operations *ops)
85{
86 if (ops)
87 smp_ops = *ops;
88};
89
90static unsigned long get_arch_pgd(pgd_t *pgd)
91{
92#ifdef CONFIG_ARM_LPAE
93 return __phys_to_pfn(virt_to_phys(pgd));
94#else
95 return virt_to_phys(pgd);
96#endif
97}
98
99#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
100static int secondary_biglittle_prepare(unsigned int cpu)
101{
102 if (!cpu_vtable[cpu])
103 cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL);
104
105 return cpu_vtable[cpu] ? 0 : -ENOMEM;
106}
107
108static void secondary_biglittle_init(void)
109{
110 init_proc_vtable(lookup_processor(read_cpuid_id())->proc);
111}
112#else
113static int secondary_biglittle_prepare(unsigned int cpu)
114{
115 return 0;
116}
117
118static void secondary_biglittle_init(void)
119{
120}
121#endif
122
123int __cpu_up(unsigned int cpu, struct task_struct *idle)
124{
125 int ret;
126
127 if (!smp_ops.smp_boot_secondary)
128 return -ENOSYS;
129
130 ret = secondary_biglittle_prepare(cpu);
131 if (ret)
132 return ret;
133
134 /*
135 * We need to tell the secondary core where to find
136 * its stack and the page tables.
137 */
138 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
139#ifdef CONFIG_ARM_MPU
140 secondary_data.mpu_rgn_info = &mpu_rgn_info;
141#endif
142
143#ifdef CONFIG_MMU
144 secondary_data.pgdir = virt_to_phys(idmap_pgd);
145 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
146#endif
147 sync_cache_w(&secondary_data);
148
149 /*
150 * Now bring the CPU into our world.
151 */
152 ret = smp_ops.smp_boot_secondary(cpu, idle);
153 if (ret == 0) {
154 /*
155 * CPU was successfully started, wait for it
156 * to come online or time out.
157 */
158 wait_for_completion_timeout(&cpu_running,
159 msecs_to_jiffies(1000));
160
161 if (!cpu_online(cpu)) {
162 pr_crit("CPU%u: failed to come online\n", cpu);
163 ret = -EIO;
164 }
165 } else {
166 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
167 }
168
169
170 memset(&secondary_data, 0, sizeof(secondary_data));
171 return ret;
172}
173
174/* platform specific SMP operations */
175void __init smp_init_cpus(void)
176{
177 if (smp_ops.smp_init_cpus)
178 smp_ops.smp_init_cpus();
179}
180
181int platform_can_secondary_boot(void)
182{
183 return !!smp_ops.smp_boot_secondary;
184}
185
186int platform_can_cpu_hotplug(void)
187{
188#ifdef CONFIG_HOTPLUG_CPU
189 if (smp_ops.cpu_kill)
190 return 1;
191#endif
192
193 return 0;
194}
195
196#ifdef CONFIG_HOTPLUG_CPU
197static int platform_cpu_kill(unsigned int cpu)
198{
199 if (smp_ops.cpu_kill)
200 return smp_ops.cpu_kill(cpu);
201 return 1;
202}
203
204static int platform_cpu_disable(unsigned int cpu)
205{
206 if (smp_ops.cpu_disable)
207 return smp_ops.cpu_disable(cpu);
208
209 return 0;
210}
211
212int platform_can_hotplug_cpu(unsigned int cpu)
213{
214 /* cpu_die must be specified to support hotplug */
215 if (!smp_ops.cpu_die)
216 return 0;
217
218 if (smp_ops.cpu_can_disable)
219 return smp_ops.cpu_can_disable(cpu);
220
221 /*
222 * By default, allow disabling all CPUs except the first one,
223 * since this is special on a lot of platforms, e.g. because
224 * of clock tick interrupts.
225 */
226 return cpu != 0;
227}
228
229/*
230 * __cpu_disable runs on the processor to be shutdown.
231 */
232int __cpu_disable(void)
233{
234 unsigned int cpu = smp_processor_id();
235 int ret;
236
237 ret = platform_cpu_disable(cpu);
238 if (ret)
239 return ret;
240
241#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
242 remove_cpu_topology(cpu);
243#endif
244
245 /*
246 * Take this CPU offline. Once we clear this, we can't return,
247 * and we must not schedule until we're ready to give up the cpu.
248 */
249 set_cpu_online(cpu, false);
250
251 /*
252 * OK - migrate IRQs away from this CPU
253 */
254 irq_migrate_all_off_this_cpu();
255
256 /*
257 * Flush user cache and TLB mappings, and then remove this CPU
258 * from the vm mask set of all processes.
259 *
260 * Caches are flushed to the Level of Unification Inner Shareable
261 * to write-back dirty lines to unified caches shared by all CPUs.
262 */
263 flush_cache_louis();
264 local_flush_tlb_all();
265
266 return 0;
267}
268
269/*
270 * called on the thread which is asking for a CPU to be shutdown -
271 * waits until shutdown has completed, or it is timed out.
272 */
273void __cpu_die(unsigned int cpu)
274{
275 if (!cpu_wait_death(cpu, 5)) {
276 pr_err("CPU%u: cpu didn't die\n", cpu);
277 return;
278 }
279 pr_debug("CPU%u: shutdown\n", cpu);
280
281 clear_tasks_mm_cpumask(cpu);
282 /*
283 * platform_cpu_kill() is generally expected to do the powering off
284 * and/or cutting of clocks to the dying CPU. Optionally, this may
285 * be done by the CPU which is dying in preference to supporting
286 * this call, but that means there is _no_ synchronisation between
287 * the requesting CPU and the dying CPU actually losing power.
288 */
289 if (!platform_cpu_kill(cpu))
290 pr_err("CPU%u: unable to kill\n", cpu);
291}
292
293/*
294 * Called from the idle thread for the CPU which has been shutdown.
295 *
296 * Note that we disable IRQs here, but do not re-enable them
297 * before returning to the caller. This is also the behaviour
298 * of the other hotplug-cpu capable cores, so presumably coming
299 * out of idle fixes this.
300 */
301void arch_cpu_idle_dead(void)
302{
303 unsigned int cpu = smp_processor_id();
304
305 idle_task_exit();
306
307 local_irq_disable();
308
309 /*
310 * Flush the data out of the L1 cache for this CPU. This must be
311 * before the completion to ensure that data is safely written out
312 * before platform_cpu_kill() gets called - which may disable
313 * *this* CPU and power down its cache.
314 */
315 flush_cache_louis();
316
317 /*
318 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
319 * this returns, power and/or clocks can be removed at any point
320 * from this CPU and its cache by platform_cpu_kill().
321 */
322 (void)cpu_report_death();
323
324 /*
325 * Ensure that the cache lines associated with that completion are
326 * written out. This covers the case where _this_ CPU is doing the
327 * powering down, to ensure that the completion is visible to the
328 * CPU waiting for this one.
329 */
330 flush_cache_louis();
331
332 /*
333 * The actual CPU shutdown procedure is at least platform (if not
334 * CPU) specific. This may remove power, or it may simply spin.
335 *
336 * Platforms are generally expected *NOT* to return from this call,
337 * although there are some which do because they have no way to
338 * power down the CPU. These platforms are the _only_ reason we
339 * have a return path which uses the fragment of assembly below.
340 *
341 * The return path should not be used for platforms which can
342 * power off the CPU.
343 */
344 if (smp_ops.cpu_die)
345 smp_ops.cpu_die(cpu);
346
347 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
348 cpu);
349
350 /*
351 * Do not return to the idle loop - jump back to the secondary
352 * cpu initialisation. There's some initialisation which needs
353 * to be repeated to undo the effects of taking the CPU offline.
354 */
355 __asm__("mov sp, %0\n"
356 " mov fp, #0\n"
357 " b secondary_start_kernel"
358 :
359 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
360}
361#endif /* CONFIG_HOTPLUG_CPU */
362
363/*
364 * Called by both boot and secondaries to move global data into
365 * per-processor storage.
366 */
367static void smp_store_cpu_info(unsigned int cpuid)
368{
369 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
370
371 cpu_info->loops_per_jiffy = loops_per_jiffy;
372 cpu_info->cpuid = read_cpuid_id();
373
374 store_cpu_topology(cpuid);
375 check_cpu_icache_size(cpuid);
376}
377
378/*
379 * This is the secondary CPU boot entry. We're using this CPUs
380 * idle thread stack, but a set of temporary page tables.
381 */
382asmlinkage void secondary_start_kernel(void)
383{
384 struct mm_struct *mm = &init_mm;
385 unsigned int cpu;
386
387 secondary_biglittle_init();
388
389 /*
390 * The identity mapping is uncached (strongly ordered), so
391 * switch away from it before attempting any exclusive accesses.
392 */
393 cpu_switch_mm(mm->pgd, mm);
394 local_flush_bp_all();
395 enter_lazy_tlb(mm, current);
396 local_flush_tlb_all();
397
398 /*
399 * All kernel threads share the same mm context; grab a
400 * reference and switch to it.
401 */
402 cpu = smp_processor_id();
403 mmgrab(mm);
404 current->active_mm = mm;
405 cpumask_set_cpu(cpu, mm_cpumask(mm));
406
407 cpu_init();
408
409#ifndef CONFIG_MMU
410 setup_vectors_base();
411#endif
412 pr_debug("CPU%u: Booted secondary processor\n", cpu);
413
414 preempt_disable();
415 trace_hardirqs_off();
416
417 /*
418 * Give the platform a chance to do its own initialisation.
419 */
420 if (smp_ops.smp_secondary_init)
421 smp_ops.smp_secondary_init(cpu);
422
423 notify_cpu_starting(cpu);
424
425 calibrate_delay();
426
427 smp_store_cpu_info(cpu);
428
429 /*
430 * OK, now it's safe to let the boot CPU continue. Wait for
431 * the CPU migration code to notice that the CPU is online
432 * before we continue - which happens after __cpu_up returns.
433 */
434 set_cpu_online(cpu, true);
435
436 check_other_bugs();
437
438 complete(&cpu_running);
439
440 local_irq_enable();
441 local_fiq_enable();
442 local_abt_enable();
443
444 /*
445 * OK, it's off to the idle thread for us
446 */
447 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
448}
449
450void __init smp_cpus_done(unsigned int max_cpus)
451{
452 int cpu;
453 unsigned long bogosum = 0;
454
455 for_each_online_cpu(cpu)
456 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
457
458 printk(KERN_INFO "SMP: Total of %d processors activated "
459 "(%lu.%02lu BogoMIPS).\n",
460 num_online_cpus(),
461 bogosum / (500000/HZ),
462 (bogosum / (5000/HZ)) % 100);
463
464 hyp_mode_check();
465}
466
467void __init smp_prepare_boot_cpu(void)
468{
469 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
470}
471
472void __init smp_prepare_cpus(unsigned int max_cpus)
473{
474 unsigned int ncores = num_possible_cpus();
475
476 init_cpu_topology();
477
478 smp_store_cpu_info(smp_processor_id());
479
480 /*
481 * are we trying to boot more cores than exist?
482 */
483 if (max_cpus > ncores)
484 max_cpus = ncores;
485 if (ncores > 1 && max_cpus) {
486 /*
487 * Initialise the present map, which describes the set of CPUs
488 * actually populated at the present time. A platform should
489 * re-initialize the map in the platforms smp_prepare_cpus()
490 * if present != possible (e.g. physical hotplug).
491 */
492 init_cpu_present(cpu_possible_mask);
493
494 /*
495 * Initialise the SCU if there are more than one CPU
496 * and let them know where to start.
497 */
498 if (smp_ops.smp_prepare_cpus)
499 smp_ops.smp_prepare_cpus(max_cpus);
500 }
501}
502
503static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
504
505void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
506{
507 if (!__smp_cross_call)
508 __smp_cross_call = fn;
509}
510
511static const char *ipi_types[NR_IPI] __tracepoint_string = {
512#define S(x,s) [x] = s
513 S(IPI_WAKEUP, "CPU wakeup interrupts"),
514 S(IPI_TIMER, "Timer broadcast interrupts"),
515 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
516 S(IPI_CALL_FUNC, "Function call interrupts"),
517 S(IPI_CPU_STOP, "CPU stop interrupts"),
518 S(IPI_IRQ_WORK, "IRQ work interrupts"),
519 S(IPI_COMPLETION, "completion interrupts"),
520};
521
522static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
523{
524 trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
525 __smp_cross_call(target, ipinr);
526}
527
528void show_ipi_list(struct seq_file *p, int prec)
529{
530 unsigned int cpu, i;
531
532 for (i = 0; i < NR_IPI; i++) {
533 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
534
535 for_each_online_cpu(cpu)
536 seq_printf(p, "%10u ",
537 __get_irq_stat(cpu, ipi_irqs[i]));
538
539 seq_printf(p, " %s\n", ipi_types[i]);
540 }
541}
542
543u64 smp_irq_stat_cpu(unsigned int cpu)
544{
545 u64 sum = 0;
546 int i;
547
548 for (i = 0; i < NR_IPI; i++)
549 sum += __get_irq_stat(cpu, ipi_irqs[i]);
550
551 return sum;
552}
553
554void arch_send_call_function_ipi_mask(const struct cpumask *mask)
555{
556 smp_cross_call(mask, IPI_CALL_FUNC);
557}
558
559void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
560{
561 smp_cross_call(mask, IPI_WAKEUP);
562}
563
564void arch_send_call_function_single_ipi(int cpu)
565{
566 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
567}
568
569#ifdef CONFIG_IRQ_WORK
570void arch_irq_work_raise(void)
571{
572 if (arch_irq_work_has_interrupt())
573 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
574}
575#endif
576
577#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
578void tick_broadcast(const struct cpumask *mask)
579{
580 smp_cross_call(mask, IPI_TIMER);
581}
582#endif
583
584static DEFINE_RAW_SPINLOCK(stop_lock);
585
586/*
587 * ipi_cpu_stop - handle IPI from smp_send_stop()
588 */
589static void ipi_cpu_stop(unsigned int cpu)
590{
591 if (system_state <= SYSTEM_RUNNING) {
592 raw_spin_lock(&stop_lock);
593 pr_crit("CPU%u: stopping\n", cpu);
594 dump_stack();
595 raw_spin_unlock(&stop_lock);
596 }
597
598 set_cpu_online(cpu, false);
599
600 local_fiq_disable();
601 local_irq_disable();
602
603 while (1) {
604 cpu_relax();
605 wfe();
606 }
607}
608
609static DEFINE_PER_CPU(struct completion *, cpu_completion);
610
611int register_ipi_completion(struct completion *completion, int cpu)
612{
613 per_cpu(cpu_completion, cpu) = completion;
614 return IPI_COMPLETION;
615}
616
617static void ipi_complete(unsigned int cpu)
618{
619 complete(per_cpu(cpu_completion, cpu));
620}
621
622/*
623 * Main handler for inter-processor interrupts
624 */
625asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
626{
627 handle_IPI(ipinr, regs);
628}
629
630void handle_IPI(int ipinr, struct pt_regs *regs)
631{
632 unsigned int cpu = smp_processor_id();
633 struct pt_regs *old_regs = set_irq_regs(regs);
634
635 if ((unsigned)ipinr < NR_IPI) {
636 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
637 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
638 }
639
640 switch (ipinr) {
641 case IPI_WAKEUP:
642 break;
643
644#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
645 case IPI_TIMER:
646 irq_enter();
647 tick_receive_broadcast();
648 irq_exit();
649 break;
650#endif
651
652 case IPI_RESCHEDULE:
653 scheduler_ipi();
654 break;
655
656 case IPI_CALL_FUNC:
657 irq_enter();
658 generic_smp_call_function_interrupt();
659 irq_exit();
660 break;
661
662 case IPI_CPU_STOP:
663 irq_enter();
664 ipi_cpu_stop(cpu);
665 irq_exit();
666 break;
667
668#ifdef CONFIG_IRQ_WORK
669 case IPI_IRQ_WORK:
670 irq_enter();
671 irq_work_run();
672 irq_exit();
673 break;
674#endif
675
676 case IPI_COMPLETION:
677 irq_enter();
678 ipi_complete(cpu);
679 irq_exit();
680 break;
681
682 case IPI_CPU_BACKTRACE:
683 printk_nmi_enter();
684 irq_enter();
685 nmi_cpu_backtrace(regs);
686 irq_exit();
687 printk_nmi_exit();
688 break;
689
690 default:
691 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
692 cpu, ipinr);
693 break;
694 }
695
696 if ((unsigned)ipinr < NR_IPI)
697 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
698 set_irq_regs(old_regs);
699}
700
701void smp_send_reschedule(int cpu)
702{
703 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
704}
705
706void smp_send_stop(void)
707{
708 unsigned long timeout;
709 struct cpumask mask;
710
711 cpumask_copy(&mask, cpu_online_mask);
712 cpumask_clear_cpu(smp_processor_id(), &mask);
713 if (!cpumask_empty(&mask))
714 smp_cross_call(&mask, IPI_CPU_STOP);
715
716 /* Wait up to one second for other CPUs to stop */
717 timeout = USEC_PER_SEC;
718 while (num_online_cpus() > 1 && timeout--)
719 udelay(1);
720
721 if (num_online_cpus() > 1)
722 pr_warn("SMP: failed to stop secondary CPUs\n");
723}
724
725/* In case panic() and panic() called at the same time on CPU1 and CPU2,
726 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
727 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
728 * kdump fails. So split out the panic_smp_self_stop() and add
729 * set_cpu_online(smp_processor_id(), false).
730 */
731void panic_smp_self_stop(void)
732{
733 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
734 smp_processor_id());
735 set_cpu_online(smp_processor_id(), false);
736 while (1)
737 cpu_relax();
738}
739
740/*
741 * not supported here
742 */
743int setup_profiling_timer(unsigned int multiplier)
744{
745 return -EINVAL;
746}
747
748#ifdef CONFIG_CPU_FREQ
749
750static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
751static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
752static unsigned long global_l_p_j_ref;
753static unsigned long global_l_p_j_ref_freq;
754
755static int cpufreq_callback(struct notifier_block *nb,
756 unsigned long val, void *data)
757{
758 struct cpufreq_freqs *freq = data;
759 struct cpumask *cpus = freq->policy->cpus;
760 int cpu, first = cpumask_first(cpus);
761 unsigned int lpj;
762
763 if (freq->flags & CPUFREQ_CONST_LOOPS)
764 return NOTIFY_OK;
765
766 if (!per_cpu(l_p_j_ref, first)) {
767 for_each_cpu(cpu, cpus) {
768 per_cpu(l_p_j_ref, cpu) =
769 per_cpu(cpu_data, cpu).loops_per_jiffy;
770 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
771 }
772
773 if (!global_l_p_j_ref) {
774 global_l_p_j_ref = loops_per_jiffy;
775 global_l_p_j_ref_freq = freq->old;
776 }
777 }
778
779 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
780 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
781 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
782 global_l_p_j_ref_freq,
783 freq->new);
784
785 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first),
786 per_cpu(l_p_j_ref_freq, first), freq->new);
787 for_each_cpu(cpu, cpus)
788 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj;
789 }
790 return NOTIFY_OK;
791}
792
793static struct notifier_block cpufreq_notifier = {
794 .notifier_call = cpufreq_callback,
795};
796
797static int __init register_cpufreq_notifier(void)
798{
799 return cpufreq_register_notifier(&cpufreq_notifier,
800 CPUFREQ_TRANSITION_NOTIFIER);
801}
802core_initcall(register_cpufreq_notifier);
803
804#endif
805
806static void raise_nmi(cpumask_t *mask)
807{
808 __smp_cross_call(mask, IPI_CPU_BACKTRACE);
809}
810
811void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
812{
813 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
814}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/smp.c
4 *
5 * Copyright (C) 2002 ARM Limited, All Rights Reserved.
6 */
7#include <linux/module.h>
8#include <linux/delay.h>
9#include <linux/init.h>
10#include <linux/spinlock.h>
11#include <linux/sched/mm.h>
12#include <linux/sched/hotplug.h>
13#include <linux/sched/task_stack.h>
14#include <linux/interrupt.h>
15#include <linux/cache.h>
16#include <linux/profile.h>
17#include <linux/errno.h>
18#include <linux/mm.h>
19#include <linux/err.h>
20#include <linux/cpu.h>
21#include <linux/seq_file.h>
22#include <linux/irq.h>
23#include <linux/nmi.h>
24#include <linux/percpu.h>
25#include <linux/clockchips.h>
26#include <linux/completion.h>
27#include <linux/cpufreq.h>
28#include <linux/irq_work.h>
29
30#include <linux/atomic.h>
31#include <asm/bugs.h>
32#include <asm/smp.h>
33#include <asm/cacheflush.h>
34#include <asm/cpu.h>
35#include <asm/cputype.h>
36#include <asm/exception.h>
37#include <asm/idmap.h>
38#include <asm/topology.h>
39#include <asm/mmu_context.h>
40#include <asm/pgtable.h>
41#include <asm/pgalloc.h>
42#include <asm/procinfo.h>
43#include <asm/processor.h>
44#include <asm/sections.h>
45#include <asm/tlbflush.h>
46#include <asm/ptrace.h>
47#include <asm/smp_plat.h>
48#include <asm/virt.h>
49#include <asm/mach/arch.h>
50#include <asm/mpu.h>
51
52#define CREATE_TRACE_POINTS
53#include <trace/events/ipi.h>
54
55/*
56 * as from 2.5, kernels no longer have an init_tasks structure
57 * so we need some other way of telling a new secondary core
58 * where to place its SVC stack
59 */
60struct secondary_data secondary_data;
61
62enum ipi_msg_type {
63 IPI_WAKEUP,
64 IPI_TIMER,
65 IPI_RESCHEDULE,
66 IPI_CALL_FUNC,
67 IPI_CPU_STOP,
68 IPI_IRQ_WORK,
69 IPI_COMPLETION,
70 /*
71 * CPU_BACKTRACE is special and not included in NR_IPI
72 * or tracable with trace_ipi_*
73 */
74 IPI_CPU_BACKTRACE,
75 /*
76 * SGI8-15 can be reserved by secure firmware, and thus may
77 * not be usable by the kernel. Please keep the above limited
78 * to at most 8 entries.
79 */
80};
81
82static DECLARE_COMPLETION(cpu_running);
83
84static struct smp_operations smp_ops __ro_after_init;
85
86void __init smp_set_ops(const struct smp_operations *ops)
87{
88 if (ops)
89 smp_ops = *ops;
90};
91
92static unsigned long get_arch_pgd(pgd_t *pgd)
93{
94#ifdef CONFIG_ARM_LPAE
95 return __phys_to_pfn(virt_to_phys(pgd));
96#else
97 return virt_to_phys(pgd);
98#endif
99}
100
101#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
102static int secondary_biglittle_prepare(unsigned int cpu)
103{
104 if (!cpu_vtable[cpu])
105 cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL);
106
107 return cpu_vtable[cpu] ? 0 : -ENOMEM;
108}
109
110static void secondary_biglittle_init(void)
111{
112 init_proc_vtable(lookup_processor(read_cpuid_id())->proc);
113}
114#else
115static int secondary_biglittle_prepare(unsigned int cpu)
116{
117 return 0;
118}
119
120static void secondary_biglittle_init(void)
121{
122}
123#endif
124
125int __cpu_up(unsigned int cpu, struct task_struct *idle)
126{
127 int ret;
128
129 if (!smp_ops.smp_boot_secondary)
130 return -ENOSYS;
131
132 ret = secondary_biglittle_prepare(cpu);
133 if (ret)
134 return ret;
135
136 /*
137 * We need to tell the secondary core where to find
138 * its stack and the page tables.
139 */
140 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
141#ifdef CONFIG_ARM_MPU
142 secondary_data.mpu_rgn_info = &mpu_rgn_info;
143#endif
144
145#ifdef CONFIG_MMU
146 secondary_data.pgdir = virt_to_phys(idmap_pgd);
147 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
148#endif
149 sync_cache_w(&secondary_data);
150
151 /*
152 * Now bring the CPU into our world.
153 */
154 ret = smp_ops.smp_boot_secondary(cpu, idle);
155 if (ret == 0) {
156 /*
157 * CPU was successfully started, wait for it
158 * to come online or time out.
159 */
160 wait_for_completion_timeout(&cpu_running,
161 msecs_to_jiffies(1000));
162
163 if (!cpu_online(cpu)) {
164 pr_crit("CPU%u: failed to come online\n", cpu);
165 ret = -EIO;
166 }
167 } else {
168 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
169 }
170
171
172 memset(&secondary_data, 0, sizeof(secondary_data));
173 return ret;
174}
175
176/* platform specific SMP operations */
177void __init smp_init_cpus(void)
178{
179 if (smp_ops.smp_init_cpus)
180 smp_ops.smp_init_cpus();
181}
182
183int platform_can_secondary_boot(void)
184{
185 return !!smp_ops.smp_boot_secondary;
186}
187
188int platform_can_cpu_hotplug(void)
189{
190#ifdef CONFIG_HOTPLUG_CPU
191 if (smp_ops.cpu_kill)
192 return 1;
193#endif
194
195 return 0;
196}
197
198#ifdef CONFIG_HOTPLUG_CPU
199static int platform_cpu_kill(unsigned int cpu)
200{
201 if (smp_ops.cpu_kill)
202 return smp_ops.cpu_kill(cpu);
203 return 1;
204}
205
206static int platform_cpu_disable(unsigned int cpu)
207{
208 if (smp_ops.cpu_disable)
209 return smp_ops.cpu_disable(cpu);
210
211 return 0;
212}
213
214int platform_can_hotplug_cpu(unsigned int cpu)
215{
216 /* cpu_die must be specified to support hotplug */
217 if (!smp_ops.cpu_die)
218 return 0;
219
220 if (smp_ops.cpu_can_disable)
221 return smp_ops.cpu_can_disable(cpu);
222
223 /*
224 * By default, allow disabling all CPUs except the first one,
225 * since this is special on a lot of platforms, e.g. because
226 * of clock tick interrupts.
227 */
228 return cpu != 0;
229}
230
231/*
232 * __cpu_disable runs on the processor to be shutdown.
233 */
234int __cpu_disable(void)
235{
236 unsigned int cpu = smp_processor_id();
237 int ret;
238
239 ret = platform_cpu_disable(cpu);
240 if (ret)
241 return ret;
242
243 /*
244 * Take this CPU offline. Once we clear this, we can't return,
245 * and we must not schedule until we're ready to give up the cpu.
246 */
247 set_cpu_online(cpu, false);
248
249 /*
250 * OK - migrate IRQs away from this CPU
251 */
252 irq_migrate_all_off_this_cpu();
253
254 /*
255 * Flush user cache and TLB mappings, and then remove this CPU
256 * from the vm mask set of all processes.
257 *
258 * Caches are flushed to the Level of Unification Inner Shareable
259 * to write-back dirty lines to unified caches shared by all CPUs.
260 */
261 flush_cache_louis();
262 local_flush_tlb_all();
263
264 return 0;
265}
266
267/*
268 * called on the thread which is asking for a CPU to be shutdown -
269 * waits until shutdown has completed, or it is timed out.
270 */
271void __cpu_die(unsigned int cpu)
272{
273 if (!cpu_wait_death(cpu, 5)) {
274 pr_err("CPU%u: cpu didn't die\n", cpu);
275 return;
276 }
277 pr_debug("CPU%u: shutdown\n", cpu);
278
279 clear_tasks_mm_cpumask(cpu);
280 /*
281 * platform_cpu_kill() is generally expected to do the powering off
282 * and/or cutting of clocks to the dying CPU. Optionally, this may
283 * be done by the CPU which is dying in preference to supporting
284 * this call, but that means there is _no_ synchronisation between
285 * the requesting CPU and the dying CPU actually losing power.
286 */
287 if (!platform_cpu_kill(cpu))
288 pr_err("CPU%u: unable to kill\n", cpu);
289}
290
291/*
292 * Called from the idle thread for the CPU which has been shutdown.
293 *
294 * Note that we disable IRQs here, but do not re-enable them
295 * before returning to the caller. This is also the behaviour
296 * of the other hotplug-cpu capable cores, so presumably coming
297 * out of idle fixes this.
298 */
299void arch_cpu_idle_dead(void)
300{
301 unsigned int cpu = smp_processor_id();
302
303 idle_task_exit();
304
305 local_irq_disable();
306
307 /*
308 * Flush the data out of the L1 cache for this CPU. This must be
309 * before the completion to ensure that data is safely written out
310 * before platform_cpu_kill() gets called - which may disable
311 * *this* CPU and power down its cache.
312 */
313 flush_cache_louis();
314
315 /*
316 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
317 * this returns, power and/or clocks can be removed at any point
318 * from this CPU and its cache by platform_cpu_kill().
319 */
320 (void)cpu_report_death();
321
322 /*
323 * Ensure that the cache lines associated with that completion are
324 * written out. This covers the case where _this_ CPU is doing the
325 * powering down, to ensure that the completion is visible to the
326 * CPU waiting for this one.
327 */
328 flush_cache_louis();
329
330 /*
331 * The actual CPU shutdown procedure is at least platform (if not
332 * CPU) specific. This may remove power, or it may simply spin.
333 *
334 * Platforms are generally expected *NOT* to return from this call,
335 * although there are some which do because they have no way to
336 * power down the CPU. These platforms are the _only_ reason we
337 * have a return path which uses the fragment of assembly below.
338 *
339 * The return path should not be used for platforms which can
340 * power off the CPU.
341 */
342 if (smp_ops.cpu_die)
343 smp_ops.cpu_die(cpu);
344
345 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
346 cpu);
347
348 /*
349 * Do not return to the idle loop - jump back to the secondary
350 * cpu initialisation. There's some initialisation which needs
351 * to be repeated to undo the effects of taking the CPU offline.
352 */
353 __asm__("mov sp, %0\n"
354 " mov fp, #0\n"
355 " b secondary_start_kernel"
356 :
357 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
358}
359#endif /* CONFIG_HOTPLUG_CPU */
360
361/*
362 * Called by both boot and secondaries to move global data into
363 * per-processor storage.
364 */
365static void smp_store_cpu_info(unsigned int cpuid)
366{
367 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
368
369 cpu_info->loops_per_jiffy = loops_per_jiffy;
370 cpu_info->cpuid = read_cpuid_id();
371
372 store_cpu_topology(cpuid);
373 check_cpu_icache_size(cpuid);
374}
375
376/*
377 * This is the secondary CPU boot entry. We're using this CPUs
378 * idle thread stack, but a set of temporary page tables.
379 */
380asmlinkage void secondary_start_kernel(void)
381{
382 struct mm_struct *mm = &init_mm;
383 unsigned int cpu;
384
385 secondary_biglittle_init();
386
387 /*
388 * The identity mapping is uncached (strongly ordered), so
389 * switch away from it before attempting any exclusive accesses.
390 */
391 cpu_switch_mm(mm->pgd, mm);
392 local_flush_bp_all();
393 enter_lazy_tlb(mm, current);
394 local_flush_tlb_all();
395
396 /*
397 * All kernel threads share the same mm context; grab a
398 * reference and switch to it.
399 */
400 cpu = smp_processor_id();
401 mmgrab(mm);
402 current->active_mm = mm;
403 cpumask_set_cpu(cpu, mm_cpumask(mm));
404
405 cpu_init();
406
407#ifndef CONFIG_MMU
408 setup_vectors_base();
409#endif
410 pr_debug("CPU%u: Booted secondary processor\n", cpu);
411
412 preempt_disable();
413 trace_hardirqs_off();
414
415 /*
416 * Give the platform a chance to do its own initialisation.
417 */
418 if (smp_ops.smp_secondary_init)
419 smp_ops.smp_secondary_init(cpu);
420
421 notify_cpu_starting(cpu);
422
423 calibrate_delay();
424
425 smp_store_cpu_info(cpu);
426
427 /*
428 * OK, now it's safe to let the boot CPU continue. Wait for
429 * the CPU migration code to notice that the CPU is online
430 * before we continue - which happens after __cpu_up returns.
431 */
432 set_cpu_online(cpu, true);
433
434 check_other_bugs();
435
436 complete(&cpu_running);
437
438 local_irq_enable();
439 local_fiq_enable();
440 local_abt_enable();
441
442 /*
443 * OK, it's off to the idle thread for us
444 */
445 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
446}
447
448void __init smp_cpus_done(unsigned int max_cpus)
449{
450 int cpu;
451 unsigned long bogosum = 0;
452
453 for_each_online_cpu(cpu)
454 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
455
456 printk(KERN_INFO "SMP: Total of %d processors activated "
457 "(%lu.%02lu BogoMIPS).\n",
458 num_online_cpus(),
459 bogosum / (500000/HZ),
460 (bogosum / (5000/HZ)) % 100);
461
462 hyp_mode_check();
463}
464
465void __init smp_prepare_boot_cpu(void)
466{
467 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
468}
469
470void __init smp_prepare_cpus(unsigned int max_cpus)
471{
472 unsigned int ncores = num_possible_cpus();
473
474 init_cpu_topology();
475
476 smp_store_cpu_info(smp_processor_id());
477
478 /*
479 * are we trying to boot more cores than exist?
480 */
481 if (max_cpus > ncores)
482 max_cpus = ncores;
483 if (ncores > 1 && max_cpus) {
484 /*
485 * Initialise the present map, which describes the set of CPUs
486 * actually populated at the present time. A platform should
487 * re-initialize the map in the platforms smp_prepare_cpus()
488 * if present != possible (e.g. physical hotplug).
489 */
490 init_cpu_present(cpu_possible_mask);
491
492 /*
493 * Initialise the SCU if there are more than one CPU
494 * and let them know where to start.
495 */
496 if (smp_ops.smp_prepare_cpus)
497 smp_ops.smp_prepare_cpus(max_cpus);
498 }
499}
500
501static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
502
503void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
504{
505 if (!__smp_cross_call)
506 __smp_cross_call = fn;
507}
508
509static const char *ipi_types[NR_IPI] __tracepoint_string = {
510#define S(x,s) [x] = s
511 S(IPI_WAKEUP, "CPU wakeup interrupts"),
512 S(IPI_TIMER, "Timer broadcast interrupts"),
513 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
514 S(IPI_CALL_FUNC, "Function call interrupts"),
515 S(IPI_CPU_STOP, "CPU stop interrupts"),
516 S(IPI_IRQ_WORK, "IRQ work interrupts"),
517 S(IPI_COMPLETION, "completion interrupts"),
518};
519
520static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
521{
522 trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
523 __smp_cross_call(target, ipinr);
524}
525
526void show_ipi_list(struct seq_file *p, int prec)
527{
528 unsigned int cpu, i;
529
530 for (i = 0; i < NR_IPI; i++) {
531 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
532
533 for_each_online_cpu(cpu)
534 seq_printf(p, "%10u ",
535 __get_irq_stat(cpu, ipi_irqs[i]));
536
537 seq_printf(p, " %s\n", ipi_types[i]);
538 }
539}
540
541u64 smp_irq_stat_cpu(unsigned int cpu)
542{
543 u64 sum = 0;
544 int i;
545
546 for (i = 0; i < NR_IPI; i++)
547 sum += __get_irq_stat(cpu, ipi_irqs[i]);
548
549 return sum;
550}
551
552void arch_send_call_function_ipi_mask(const struct cpumask *mask)
553{
554 smp_cross_call(mask, IPI_CALL_FUNC);
555}
556
557void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
558{
559 smp_cross_call(mask, IPI_WAKEUP);
560}
561
562void arch_send_call_function_single_ipi(int cpu)
563{
564 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
565}
566
567#ifdef CONFIG_IRQ_WORK
568void arch_irq_work_raise(void)
569{
570 if (arch_irq_work_has_interrupt())
571 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
572}
573#endif
574
575#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
576void tick_broadcast(const struct cpumask *mask)
577{
578 smp_cross_call(mask, IPI_TIMER);
579}
580#endif
581
582static DEFINE_RAW_SPINLOCK(stop_lock);
583
584/*
585 * ipi_cpu_stop - handle IPI from smp_send_stop()
586 */
587static void ipi_cpu_stop(unsigned int cpu)
588{
589 if (system_state <= SYSTEM_RUNNING) {
590 raw_spin_lock(&stop_lock);
591 pr_crit("CPU%u: stopping\n", cpu);
592 dump_stack();
593 raw_spin_unlock(&stop_lock);
594 }
595
596 set_cpu_online(cpu, false);
597
598 local_fiq_disable();
599 local_irq_disable();
600
601 while (1) {
602 cpu_relax();
603 wfe();
604 }
605}
606
607static DEFINE_PER_CPU(struct completion *, cpu_completion);
608
609int register_ipi_completion(struct completion *completion, int cpu)
610{
611 per_cpu(cpu_completion, cpu) = completion;
612 return IPI_COMPLETION;
613}
614
615static void ipi_complete(unsigned int cpu)
616{
617 complete(per_cpu(cpu_completion, cpu));
618}
619
620/*
621 * Main handler for inter-processor interrupts
622 */
623asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
624{
625 handle_IPI(ipinr, regs);
626}
627
628void handle_IPI(int ipinr, struct pt_regs *regs)
629{
630 unsigned int cpu = smp_processor_id();
631 struct pt_regs *old_regs = set_irq_regs(regs);
632
633 if ((unsigned)ipinr < NR_IPI) {
634 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
635 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
636 }
637
638 switch (ipinr) {
639 case IPI_WAKEUP:
640 break;
641
642#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
643 case IPI_TIMER:
644 irq_enter();
645 tick_receive_broadcast();
646 irq_exit();
647 break;
648#endif
649
650 case IPI_RESCHEDULE:
651 scheduler_ipi();
652 break;
653
654 case IPI_CALL_FUNC:
655 irq_enter();
656 generic_smp_call_function_interrupt();
657 irq_exit();
658 break;
659
660 case IPI_CPU_STOP:
661 irq_enter();
662 ipi_cpu_stop(cpu);
663 irq_exit();
664 break;
665
666#ifdef CONFIG_IRQ_WORK
667 case IPI_IRQ_WORK:
668 irq_enter();
669 irq_work_run();
670 irq_exit();
671 break;
672#endif
673
674 case IPI_COMPLETION:
675 irq_enter();
676 ipi_complete(cpu);
677 irq_exit();
678 break;
679
680 case IPI_CPU_BACKTRACE:
681 printk_nmi_enter();
682 irq_enter();
683 nmi_cpu_backtrace(regs);
684 irq_exit();
685 printk_nmi_exit();
686 break;
687
688 default:
689 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
690 cpu, ipinr);
691 break;
692 }
693
694 if ((unsigned)ipinr < NR_IPI)
695 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
696 set_irq_regs(old_regs);
697}
698
699void smp_send_reschedule(int cpu)
700{
701 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
702}
703
704void smp_send_stop(void)
705{
706 unsigned long timeout;
707 struct cpumask mask;
708
709 cpumask_copy(&mask, cpu_online_mask);
710 cpumask_clear_cpu(smp_processor_id(), &mask);
711 if (!cpumask_empty(&mask))
712 smp_cross_call(&mask, IPI_CPU_STOP);
713
714 /* Wait up to one second for other CPUs to stop */
715 timeout = USEC_PER_SEC;
716 while (num_online_cpus() > 1 && timeout--)
717 udelay(1);
718
719 if (num_online_cpus() > 1)
720 pr_warn("SMP: failed to stop secondary CPUs\n");
721}
722
723/* In case panic() and panic() called at the same time on CPU1 and CPU2,
724 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
725 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
726 * kdump fails. So split out the panic_smp_self_stop() and add
727 * set_cpu_online(smp_processor_id(), false).
728 */
729void panic_smp_self_stop(void)
730{
731 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
732 smp_processor_id());
733 set_cpu_online(smp_processor_id(), false);
734 while (1)
735 cpu_relax();
736}
737
738/*
739 * not supported here
740 */
741int setup_profiling_timer(unsigned int multiplier)
742{
743 return -EINVAL;
744}
745
746#ifdef CONFIG_CPU_FREQ
747
748static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
749static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
750static unsigned long global_l_p_j_ref;
751static unsigned long global_l_p_j_ref_freq;
752
753static int cpufreq_callback(struct notifier_block *nb,
754 unsigned long val, void *data)
755{
756 struct cpufreq_freqs *freq = data;
757 struct cpumask *cpus = freq->policy->cpus;
758 int cpu, first = cpumask_first(cpus);
759 unsigned int lpj;
760
761 if (freq->flags & CPUFREQ_CONST_LOOPS)
762 return NOTIFY_OK;
763
764 if (!per_cpu(l_p_j_ref, first)) {
765 for_each_cpu(cpu, cpus) {
766 per_cpu(l_p_j_ref, cpu) =
767 per_cpu(cpu_data, cpu).loops_per_jiffy;
768 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
769 }
770
771 if (!global_l_p_j_ref) {
772 global_l_p_j_ref = loops_per_jiffy;
773 global_l_p_j_ref_freq = freq->old;
774 }
775 }
776
777 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
778 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
779 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
780 global_l_p_j_ref_freq,
781 freq->new);
782
783 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first),
784 per_cpu(l_p_j_ref_freq, first), freq->new);
785 for_each_cpu(cpu, cpus)
786 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj;
787 }
788 return NOTIFY_OK;
789}
790
791static struct notifier_block cpufreq_notifier = {
792 .notifier_call = cpufreq_callback,
793};
794
795static int __init register_cpufreq_notifier(void)
796{
797 return cpufreq_register_notifier(&cpufreq_notifier,
798 CPUFREQ_TRANSITION_NOTIFIER);
799}
800core_initcall(register_cpufreq_notifier);
801
802#endif
803
804static void raise_nmi(cpumask_t *mask)
805{
806 __smp_cross_call(mask, IPI_CPU_BACKTRACE);
807}
808
809void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
810{
811 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
812}