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1/*
2 * linux/arch/arm/kernel/smp.c
3 *
4 * Copyright (C) 2002 ARM Limited, All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/module.h>
11#include <linux/delay.h>
12#include <linux/init.h>
13#include <linux/spinlock.h>
14#include <linux/sched.h>
15#include <linux/interrupt.h>
16#include <linux/cache.h>
17#include <linux/profile.h>
18#include <linux/errno.h>
19#include <linux/mm.h>
20#include <linux/err.h>
21#include <linux/cpu.h>
22#include <linux/seq_file.h>
23#include <linux/irq.h>
24#include <linux/nmi.h>
25#include <linux/percpu.h>
26#include <linux/clockchips.h>
27#include <linux/completion.h>
28#include <linux/cpufreq.h>
29#include <linux/irq_work.h>
30
31#include <linux/atomic.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/processor.h>
43#include <asm/sections.h>
44#include <asm/tlbflush.h>
45#include <asm/ptrace.h>
46#include <asm/smp_plat.h>
47#include <asm/virt.h>
48#include <asm/mach/arch.h>
49#include <asm/mpu.h>
50
51#define CREATE_TRACE_POINTS
52#include <trace/events/ipi.h>
53
54/*
55 * as from 2.5, kernels no longer have an init_tasks structure
56 * so we need some other way of telling a new secondary core
57 * where to place its SVC stack
58 */
59struct secondary_data secondary_data;
60
61/*
62 * control for which core is the next to come out of the secondary
63 * boot "holding pen"
64 */
65volatile int pen_release = -1;
66
67enum ipi_msg_type {
68 IPI_WAKEUP,
69 IPI_TIMER,
70 IPI_RESCHEDULE,
71 IPI_CALL_FUNC,
72 IPI_CPU_STOP,
73 IPI_IRQ_WORK,
74 IPI_COMPLETION,
75 IPI_CPU_BACKTRACE,
76 /*
77 * SGI8-15 can be reserved by secure firmware, and thus may
78 * not be usable by the kernel. Please keep the above limited
79 * to at most 8 entries.
80 */
81};
82
83static DECLARE_COMPLETION(cpu_running);
84
85static struct smp_operations smp_ops;
86
87void __init smp_set_ops(const struct smp_operations *ops)
88{
89 if (ops)
90 smp_ops = *ops;
91};
92
93static unsigned long get_arch_pgd(pgd_t *pgd)
94{
95#ifdef CONFIG_ARM_LPAE
96 return __phys_to_pfn(virt_to_phys(pgd));
97#else
98 return virt_to_phys(pgd);
99#endif
100}
101
102int __cpu_up(unsigned int cpu, struct task_struct *idle)
103{
104 int ret;
105
106 if (!smp_ops.smp_boot_secondary)
107 return -ENOSYS;
108
109 /*
110 * We need to tell the secondary core where to find
111 * its stack and the page tables.
112 */
113 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
114#ifdef CONFIG_ARM_MPU
115 secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr;
116#endif
117
118#ifdef CONFIG_MMU
119 secondary_data.pgdir = virt_to_phys(idmap_pgd);
120 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
121#endif
122 sync_cache_w(&secondary_data);
123
124 /*
125 * Now bring the CPU into our world.
126 */
127 ret = smp_ops.smp_boot_secondary(cpu, idle);
128 if (ret == 0) {
129 /*
130 * CPU was successfully started, wait for it
131 * to come online or time out.
132 */
133 wait_for_completion_timeout(&cpu_running,
134 msecs_to_jiffies(1000));
135
136 if (!cpu_online(cpu)) {
137 pr_crit("CPU%u: failed to come online\n", cpu);
138 ret = -EIO;
139 }
140 } else {
141 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
142 }
143
144
145 memset(&secondary_data, 0, sizeof(secondary_data));
146 return ret;
147}
148
149/* platform specific SMP operations */
150void __init smp_init_cpus(void)
151{
152 if (smp_ops.smp_init_cpus)
153 smp_ops.smp_init_cpus();
154}
155
156int platform_can_secondary_boot(void)
157{
158 return !!smp_ops.smp_boot_secondary;
159}
160
161int platform_can_cpu_hotplug(void)
162{
163#ifdef CONFIG_HOTPLUG_CPU
164 if (smp_ops.cpu_kill)
165 return 1;
166#endif
167
168 return 0;
169}
170
171#ifdef CONFIG_HOTPLUG_CPU
172static int platform_cpu_kill(unsigned int cpu)
173{
174 if (smp_ops.cpu_kill)
175 return smp_ops.cpu_kill(cpu);
176 return 1;
177}
178
179static int platform_cpu_disable(unsigned int cpu)
180{
181 if (smp_ops.cpu_disable)
182 return smp_ops.cpu_disable(cpu);
183
184 return 0;
185}
186
187int platform_can_hotplug_cpu(unsigned int cpu)
188{
189 /* cpu_die must be specified to support hotplug */
190 if (!smp_ops.cpu_die)
191 return 0;
192
193 if (smp_ops.cpu_can_disable)
194 return smp_ops.cpu_can_disable(cpu);
195
196 /*
197 * By default, allow disabling all CPUs except the first one,
198 * since this is special on a lot of platforms, e.g. because
199 * of clock tick interrupts.
200 */
201 return cpu != 0;
202}
203
204/*
205 * __cpu_disable runs on the processor to be shutdown.
206 */
207int __cpu_disable(void)
208{
209 unsigned int cpu = smp_processor_id();
210 int ret;
211
212 ret = platform_cpu_disable(cpu);
213 if (ret)
214 return ret;
215
216 /*
217 * Take this CPU offline. Once we clear this, we can't return,
218 * and we must not schedule until we're ready to give up the cpu.
219 */
220 set_cpu_online(cpu, false);
221
222 /*
223 * OK - migrate IRQs away from this CPU
224 */
225 migrate_irqs();
226
227 /*
228 * Flush user cache and TLB mappings, and then remove this CPU
229 * from the vm mask set of all processes.
230 *
231 * Caches are flushed to the Level of Unification Inner Shareable
232 * to write-back dirty lines to unified caches shared by all CPUs.
233 */
234 flush_cache_louis();
235 local_flush_tlb_all();
236
237 clear_tasks_mm_cpumask(cpu);
238
239 return 0;
240}
241
242static DECLARE_COMPLETION(cpu_died);
243
244/*
245 * called on the thread which is asking for a CPU to be shutdown -
246 * waits until shutdown has completed, or it is timed out.
247 */
248void __cpu_die(unsigned int cpu)
249{
250 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
251 pr_err("CPU%u: cpu didn't die\n", cpu);
252 return;
253 }
254 pr_notice("CPU%u: shutdown\n", cpu);
255
256 /*
257 * platform_cpu_kill() is generally expected to do the powering off
258 * and/or cutting of clocks to the dying CPU. Optionally, this may
259 * be done by the CPU which is dying in preference to supporting
260 * this call, but that means there is _no_ synchronisation between
261 * the requesting CPU and the dying CPU actually losing power.
262 */
263 if (!platform_cpu_kill(cpu))
264 pr_err("CPU%u: unable to kill\n", cpu);
265}
266
267/*
268 * Called from the idle thread for the CPU which has been shutdown.
269 *
270 * Note that we disable IRQs here, but do not re-enable them
271 * before returning to the caller. This is also the behaviour
272 * of the other hotplug-cpu capable cores, so presumably coming
273 * out of idle fixes this.
274 */
275void arch_cpu_idle_dead(void)
276{
277 unsigned int cpu = smp_processor_id();
278
279 idle_task_exit();
280
281 local_irq_disable();
282
283 /*
284 * Flush the data out of the L1 cache for this CPU. This must be
285 * before the completion to ensure that data is safely written out
286 * before platform_cpu_kill() gets called - which may disable
287 * *this* CPU and power down its cache.
288 */
289 flush_cache_louis();
290
291 /*
292 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
293 * this returns, power and/or clocks can be removed at any point
294 * from this CPU and its cache by platform_cpu_kill().
295 */
296 complete(&cpu_died);
297
298 /*
299 * Ensure that the cache lines associated with that completion are
300 * written out. This covers the case where _this_ CPU is doing the
301 * powering down, to ensure that the completion is visible to the
302 * CPU waiting for this one.
303 */
304 flush_cache_louis();
305
306 /*
307 * The actual CPU shutdown procedure is at least platform (if not
308 * CPU) specific. This may remove power, or it may simply spin.
309 *
310 * Platforms are generally expected *NOT* to return from this call,
311 * although there are some which do because they have no way to
312 * power down the CPU. These platforms are the _only_ reason we
313 * have a return path which uses the fragment of assembly below.
314 *
315 * The return path should not be used for platforms which can
316 * power off the CPU.
317 */
318 if (smp_ops.cpu_die)
319 smp_ops.cpu_die(cpu);
320
321 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
322 cpu);
323
324 /*
325 * Do not return to the idle loop - jump back to the secondary
326 * cpu initialisation. There's some initialisation which needs
327 * to be repeated to undo the effects of taking the CPU offline.
328 */
329 __asm__("mov sp, %0\n"
330 " mov fp, #0\n"
331 " b secondary_start_kernel"
332 :
333 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
334}
335#endif /* CONFIG_HOTPLUG_CPU */
336
337/*
338 * Called by both boot and secondaries to move global data into
339 * per-processor storage.
340 */
341static void smp_store_cpu_info(unsigned int cpuid)
342{
343 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
344
345 cpu_info->loops_per_jiffy = loops_per_jiffy;
346 cpu_info->cpuid = read_cpuid_id();
347
348 store_cpu_topology(cpuid);
349}
350
351/*
352 * This is the secondary CPU boot entry. We're using this CPUs
353 * idle thread stack, but a set of temporary page tables.
354 */
355asmlinkage void secondary_start_kernel(void)
356{
357 struct mm_struct *mm = &init_mm;
358 unsigned int cpu;
359
360 /*
361 * The identity mapping is uncached (strongly ordered), so
362 * switch away from it before attempting any exclusive accesses.
363 */
364 cpu_switch_mm(mm->pgd, mm);
365 local_flush_bp_all();
366 enter_lazy_tlb(mm, current);
367 local_flush_tlb_all();
368
369 /*
370 * All kernel threads share the same mm context; grab a
371 * reference and switch to it.
372 */
373 cpu = smp_processor_id();
374 atomic_inc(&mm->mm_count);
375 current->active_mm = mm;
376 cpumask_set_cpu(cpu, mm_cpumask(mm));
377
378 cpu_init();
379
380 pr_debug("CPU%u: Booted secondary processor\n", cpu);
381
382 preempt_disable();
383 trace_hardirqs_off();
384
385 /*
386 * Give the platform a chance to do its own initialisation.
387 */
388 if (smp_ops.smp_secondary_init)
389 smp_ops.smp_secondary_init(cpu);
390
391 notify_cpu_starting(cpu);
392
393 calibrate_delay();
394
395 smp_store_cpu_info(cpu);
396
397 /*
398 * OK, now it's safe to let the boot CPU continue. Wait for
399 * the CPU migration code to notice that the CPU is online
400 * before we continue - which happens after __cpu_up returns.
401 */
402 set_cpu_online(cpu, true);
403 complete(&cpu_running);
404
405 local_irq_enable();
406 local_fiq_enable();
407 local_abt_enable();
408
409 /*
410 * OK, it's off to the idle thread for us
411 */
412 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
413}
414
415void __init smp_cpus_done(unsigned int max_cpus)
416{
417 int cpu;
418 unsigned long bogosum = 0;
419
420 for_each_online_cpu(cpu)
421 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
422
423 printk(KERN_INFO "SMP: Total of %d processors activated "
424 "(%lu.%02lu BogoMIPS).\n",
425 num_online_cpus(),
426 bogosum / (500000/HZ),
427 (bogosum / (5000/HZ)) % 100);
428
429 hyp_mode_check();
430}
431
432void __init smp_prepare_boot_cpu(void)
433{
434 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
435}
436
437void __init smp_prepare_cpus(unsigned int max_cpus)
438{
439 unsigned int ncores = num_possible_cpus();
440
441 init_cpu_topology();
442
443 smp_store_cpu_info(smp_processor_id());
444
445 /*
446 * are we trying to boot more cores than exist?
447 */
448 if (max_cpus > ncores)
449 max_cpus = ncores;
450 if (ncores > 1 && max_cpus) {
451 /*
452 * Initialise the present map, which describes the set of CPUs
453 * actually populated at the present time. A platform should
454 * re-initialize the map in the platforms smp_prepare_cpus()
455 * if present != possible (e.g. physical hotplug).
456 */
457 init_cpu_present(cpu_possible_mask);
458
459 /*
460 * Initialise the SCU if there are more than one CPU
461 * and let them know where to start.
462 */
463 if (smp_ops.smp_prepare_cpus)
464 smp_ops.smp_prepare_cpus(max_cpus);
465 }
466}
467
468static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
469
470void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
471{
472 if (!__smp_cross_call)
473 __smp_cross_call = fn;
474}
475
476static const char *ipi_types[NR_IPI] __tracepoint_string = {
477#define S(x,s) [x] = s
478 S(IPI_WAKEUP, "CPU wakeup interrupts"),
479 S(IPI_TIMER, "Timer broadcast interrupts"),
480 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
481 S(IPI_CALL_FUNC, "Function call interrupts"),
482 S(IPI_CPU_STOP, "CPU stop interrupts"),
483 S(IPI_IRQ_WORK, "IRQ work interrupts"),
484 S(IPI_COMPLETION, "completion interrupts"),
485};
486
487static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
488{
489 trace_ipi_raise(target, ipi_types[ipinr]);
490 __smp_cross_call(target, ipinr);
491}
492
493void show_ipi_list(struct seq_file *p, int prec)
494{
495 unsigned int cpu, i;
496
497 for (i = 0; i < NR_IPI; i++) {
498 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
499
500 for_each_online_cpu(cpu)
501 seq_printf(p, "%10u ",
502 __get_irq_stat(cpu, ipi_irqs[i]));
503
504 seq_printf(p, " %s\n", ipi_types[i]);
505 }
506}
507
508u64 smp_irq_stat_cpu(unsigned int cpu)
509{
510 u64 sum = 0;
511 int i;
512
513 for (i = 0; i < NR_IPI; i++)
514 sum += __get_irq_stat(cpu, ipi_irqs[i]);
515
516 return sum;
517}
518
519void arch_send_call_function_ipi_mask(const struct cpumask *mask)
520{
521 smp_cross_call(mask, IPI_CALL_FUNC);
522}
523
524void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
525{
526 smp_cross_call(mask, IPI_WAKEUP);
527}
528
529void arch_send_call_function_single_ipi(int cpu)
530{
531 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
532}
533
534#ifdef CONFIG_IRQ_WORK
535void arch_irq_work_raise(void)
536{
537 if (arch_irq_work_has_interrupt())
538 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
539}
540#endif
541
542#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
543void tick_broadcast(const struct cpumask *mask)
544{
545 smp_cross_call(mask, IPI_TIMER);
546}
547#endif
548
549static DEFINE_RAW_SPINLOCK(stop_lock);
550
551/*
552 * ipi_cpu_stop - handle IPI from smp_send_stop()
553 */
554static void ipi_cpu_stop(unsigned int cpu)
555{
556 if (system_state == SYSTEM_BOOTING ||
557 system_state == SYSTEM_RUNNING) {
558 raw_spin_lock(&stop_lock);
559 pr_crit("CPU%u: stopping\n", cpu);
560 dump_stack();
561 raw_spin_unlock(&stop_lock);
562 }
563
564 set_cpu_online(cpu, false);
565
566 local_fiq_disable();
567 local_irq_disable();
568
569 while (1)
570 cpu_relax();
571}
572
573static DEFINE_PER_CPU(struct completion *, cpu_completion);
574
575int register_ipi_completion(struct completion *completion, int cpu)
576{
577 per_cpu(cpu_completion, cpu) = completion;
578 return IPI_COMPLETION;
579}
580
581static void ipi_complete(unsigned int cpu)
582{
583 complete(per_cpu(cpu_completion, cpu));
584}
585
586/*
587 * Main handler for inter-processor interrupts
588 */
589asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
590{
591 handle_IPI(ipinr, regs);
592}
593
594void handle_IPI(int ipinr, struct pt_regs *regs)
595{
596 unsigned int cpu = smp_processor_id();
597 struct pt_regs *old_regs = set_irq_regs(regs);
598
599 if ((unsigned)ipinr < NR_IPI) {
600 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
601 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
602 }
603
604 switch (ipinr) {
605 case IPI_WAKEUP:
606 break;
607
608#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
609 case IPI_TIMER:
610 irq_enter();
611 tick_receive_broadcast();
612 irq_exit();
613 break;
614#endif
615
616 case IPI_RESCHEDULE:
617 scheduler_ipi();
618 break;
619
620 case IPI_CALL_FUNC:
621 irq_enter();
622 generic_smp_call_function_interrupt();
623 irq_exit();
624 break;
625
626 case IPI_CPU_STOP:
627 irq_enter();
628 ipi_cpu_stop(cpu);
629 irq_exit();
630 break;
631
632#ifdef CONFIG_IRQ_WORK
633 case IPI_IRQ_WORK:
634 irq_enter();
635 irq_work_run();
636 irq_exit();
637 break;
638#endif
639
640 case IPI_COMPLETION:
641 irq_enter();
642 ipi_complete(cpu);
643 irq_exit();
644 break;
645
646 case IPI_CPU_BACKTRACE:
647 irq_enter();
648 nmi_cpu_backtrace(regs);
649 irq_exit();
650 break;
651
652 default:
653 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
654 cpu, ipinr);
655 break;
656 }
657
658 if ((unsigned)ipinr < NR_IPI)
659 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
660 set_irq_regs(old_regs);
661}
662
663void smp_send_reschedule(int cpu)
664{
665 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
666}
667
668void smp_send_stop(void)
669{
670 unsigned long timeout;
671 struct cpumask mask;
672
673 cpumask_copy(&mask, cpu_online_mask);
674 cpumask_clear_cpu(smp_processor_id(), &mask);
675 if (!cpumask_empty(&mask))
676 smp_cross_call(&mask, IPI_CPU_STOP);
677
678 /* Wait up to one second for other CPUs to stop */
679 timeout = USEC_PER_SEC;
680 while (num_online_cpus() > 1 && timeout--)
681 udelay(1);
682
683 if (num_online_cpus() > 1)
684 pr_warn("SMP: failed to stop secondary CPUs\n");
685}
686
687/*
688 * not supported here
689 */
690int setup_profiling_timer(unsigned int multiplier)
691{
692 return -EINVAL;
693}
694
695#ifdef CONFIG_CPU_FREQ
696
697static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
698static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
699static unsigned long global_l_p_j_ref;
700static unsigned long global_l_p_j_ref_freq;
701
702static int cpufreq_callback(struct notifier_block *nb,
703 unsigned long val, void *data)
704{
705 struct cpufreq_freqs *freq = data;
706 int cpu = freq->cpu;
707
708 if (freq->flags & CPUFREQ_CONST_LOOPS)
709 return NOTIFY_OK;
710
711 if (!per_cpu(l_p_j_ref, cpu)) {
712 per_cpu(l_p_j_ref, cpu) =
713 per_cpu(cpu_data, cpu).loops_per_jiffy;
714 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
715 if (!global_l_p_j_ref) {
716 global_l_p_j_ref = loops_per_jiffy;
717 global_l_p_j_ref_freq = freq->old;
718 }
719 }
720
721 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
722 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
723 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
724 global_l_p_j_ref_freq,
725 freq->new);
726 per_cpu(cpu_data, cpu).loops_per_jiffy =
727 cpufreq_scale(per_cpu(l_p_j_ref, cpu),
728 per_cpu(l_p_j_ref_freq, cpu),
729 freq->new);
730 }
731 return NOTIFY_OK;
732}
733
734static struct notifier_block cpufreq_notifier = {
735 .notifier_call = cpufreq_callback,
736};
737
738static int __init register_cpufreq_notifier(void)
739{
740 return cpufreq_register_notifier(&cpufreq_notifier,
741 CPUFREQ_TRANSITION_NOTIFIER);
742}
743core_initcall(register_cpufreq_notifier);
744
745#endif
746
747static void raise_nmi(cpumask_t *mask)
748{
749 /*
750 * Generate the backtrace directly if we are running in a calling
751 * context that is not preemptible by the backtrace IPI. Note
752 * that nmi_cpu_backtrace() automatically removes the current cpu
753 * from mask.
754 */
755 if (cpumask_test_cpu(smp_processor_id(), mask) && irqs_disabled())
756 nmi_cpu_backtrace(NULL);
757
758 smp_cross_call(mask, IPI_CPU_BACKTRACE);
759}
760
761void arch_trigger_all_cpu_backtrace(bool include_self)
762{
763 nmi_trigger_all_cpu_backtrace(include_self, raise_nmi);
764}
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#include <linux/kernel_stat.h>
30
31#include <linux/atomic.h>
32#include <asm/bugs.h>
33#include <asm/smp.h>
34#include <asm/cacheflush.h>
35#include <asm/cpu.h>
36#include <asm/cputype.h>
37#include <asm/exception.h>
38#include <asm/idmap.h>
39#include <asm/topology.h>
40#include <asm/mmu_context.h>
41#include <asm/procinfo.h>
42#include <asm/processor.h>
43#include <asm/sections.h>
44#include <asm/tlbflush.h>
45#include <asm/ptrace.h>
46#include <asm/smp_plat.h>
47#include <asm/virt.h>
48#include <asm/mach/arch.h>
49#include <asm/mpu.h>
50
51#define CREATE_TRACE_POINTS
52#include <trace/events/ipi.h>
53
54/*
55 * as from 2.5, kernels no longer have an init_tasks structure
56 * so we need some other way of telling a new secondary core
57 * where to place its SVC stack
58 */
59struct secondary_data secondary_data;
60
61enum ipi_msg_type {
62 IPI_WAKEUP,
63 IPI_TIMER,
64 IPI_RESCHEDULE,
65 IPI_CALL_FUNC,
66 IPI_CPU_STOP,
67 IPI_IRQ_WORK,
68 IPI_COMPLETION,
69 NR_IPI,
70 /*
71 * CPU_BACKTRACE is special and not included in NR_IPI
72 * or tracable with trace_ipi_*
73 */
74 IPI_CPU_BACKTRACE = NR_IPI,
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 MAX_IPI
81};
82
83static int ipi_irq_base __read_mostly;
84static int nr_ipi __read_mostly = NR_IPI;
85static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly;
86
87static void ipi_setup(int cpu);
88
89static DECLARE_COMPLETION(cpu_running);
90
91static struct smp_operations smp_ops __ro_after_init;
92
93void __init smp_set_ops(const struct smp_operations *ops)
94{
95 if (ops)
96 smp_ops = *ops;
97};
98
99static unsigned long get_arch_pgd(pgd_t *pgd)
100{
101#ifdef CONFIG_ARM_LPAE
102 return __phys_to_pfn(virt_to_phys(pgd));
103#else
104 return virt_to_phys(pgd);
105#endif
106}
107
108#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
109static int secondary_biglittle_prepare(unsigned int cpu)
110{
111 if (!cpu_vtable[cpu])
112 cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL);
113
114 return cpu_vtable[cpu] ? 0 : -ENOMEM;
115}
116
117static void secondary_biglittle_init(void)
118{
119 init_proc_vtable(lookup_processor(read_cpuid_id())->proc);
120}
121#else
122static int secondary_biglittle_prepare(unsigned int cpu)
123{
124 return 0;
125}
126
127static void secondary_biglittle_init(void)
128{
129}
130#endif
131
132int __cpu_up(unsigned int cpu, struct task_struct *idle)
133{
134 int ret;
135
136 if (!smp_ops.smp_boot_secondary)
137 return -ENOSYS;
138
139 ret = secondary_biglittle_prepare(cpu);
140 if (ret)
141 return ret;
142
143 /*
144 * We need to tell the secondary core where to find
145 * its stack and the page tables.
146 */
147 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
148#ifdef CONFIG_ARM_MPU
149 secondary_data.mpu_rgn_info = &mpu_rgn_info;
150#endif
151
152#ifdef CONFIG_MMU
153 secondary_data.pgdir = virt_to_phys(idmap_pgd);
154 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
155#endif
156 secondary_data.task = idle;
157 sync_cache_w(&secondary_data);
158
159 /*
160 * Now bring the CPU into our world.
161 */
162 ret = smp_ops.smp_boot_secondary(cpu, idle);
163 if (ret == 0) {
164 /*
165 * CPU was successfully started, wait for it
166 * to come online or time out.
167 */
168 wait_for_completion_timeout(&cpu_running,
169 msecs_to_jiffies(1000));
170
171 if (!cpu_online(cpu)) {
172 pr_crit("CPU%u: failed to come online\n", cpu);
173 ret = -EIO;
174 }
175 } else {
176 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
177 }
178
179
180 memset(&secondary_data, 0, sizeof(secondary_data));
181 return ret;
182}
183
184/* platform specific SMP operations */
185void __init smp_init_cpus(void)
186{
187 if (smp_ops.smp_init_cpus)
188 smp_ops.smp_init_cpus();
189}
190
191int platform_can_secondary_boot(void)
192{
193 return !!smp_ops.smp_boot_secondary;
194}
195
196int platform_can_cpu_hotplug(void)
197{
198#ifdef CONFIG_HOTPLUG_CPU
199 if (smp_ops.cpu_kill)
200 return 1;
201#endif
202
203 return 0;
204}
205
206#ifdef CONFIG_HOTPLUG_CPU
207static int platform_cpu_kill(unsigned int cpu)
208{
209 if (smp_ops.cpu_kill)
210 return smp_ops.cpu_kill(cpu);
211 return 1;
212}
213
214static int platform_cpu_disable(unsigned int cpu)
215{
216 if (smp_ops.cpu_disable)
217 return smp_ops.cpu_disable(cpu);
218
219 return 0;
220}
221
222int platform_can_hotplug_cpu(unsigned int cpu)
223{
224 /* cpu_die must be specified to support hotplug */
225 if (!smp_ops.cpu_die)
226 return 0;
227
228 if (smp_ops.cpu_can_disable)
229 return smp_ops.cpu_can_disable(cpu);
230
231 /*
232 * By default, allow disabling all CPUs except the first one,
233 * since this is special on a lot of platforms, e.g. because
234 * of clock tick interrupts.
235 */
236 return cpu != 0;
237}
238
239static void ipi_teardown(int cpu)
240{
241 int i;
242
243 if (WARN_ON_ONCE(!ipi_irq_base))
244 return;
245
246 for (i = 0; i < nr_ipi; i++)
247 disable_percpu_irq(ipi_irq_base + i);
248}
249
250/*
251 * __cpu_disable runs on the processor to be shutdown.
252 */
253int __cpu_disable(void)
254{
255 unsigned int cpu = smp_processor_id();
256 int ret;
257
258 ret = platform_cpu_disable(cpu);
259 if (ret)
260 return ret;
261
262#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
263 remove_cpu_topology(cpu);
264#endif
265
266 /*
267 * Take this CPU offline. Once we clear this, we can't return,
268 * and we must not schedule until we're ready to give up the cpu.
269 */
270 set_cpu_online(cpu, false);
271 ipi_teardown(cpu);
272
273 /*
274 * OK - migrate IRQs away from this CPU
275 */
276 irq_migrate_all_off_this_cpu();
277
278 /*
279 * Flush user cache and TLB mappings, and then remove this CPU
280 * from the vm mask set of all processes.
281 *
282 * Caches are flushed to the Level of Unification Inner Shareable
283 * to write-back dirty lines to unified caches shared by all CPUs.
284 */
285 flush_cache_louis();
286 local_flush_tlb_all();
287
288 return 0;
289}
290
291/*
292 * called on the thread which is asking for a CPU to be shutdown -
293 * waits until shutdown has completed, or it is timed out.
294 */
295void __cpu_die(unsigned int cpu)
296{
297 if (!cpu_wait_death(cpu, 5)) {
298 pr_err("CPU%u: cpu didn't die\n", cpu);
299 return;
300 }
301 pr_debug("CPU%u: shutdown\n", cpu);
302
303 clear_tasks_mm_cpumask(cpu);
304 /*
305 * platform_cpu_kill() is generally expected to do the powering off
306 * and/or cutting of clocks to the dying CPU. Optionally, this may
307 * be done by the CPU which is dying in preference to supporting
308 * this call, but that means there is _no_ synchronisation between
309 * the requesting CPU and the dying CPU actually losing power.
310 */
311 if (!platform_cpu_kill(cpu))
312 pr_err("CPU%u: unable to kill\n", cpu);
313}
314
315/*
316 * Called from the idle thread for the CPU which has been shutdown.
317 *
318 * Note that we disable IRQs here, but do not re-enable them
319 * before returning to the caller. This is also the behaviour
320 * of the other hotplug-cpu capable cores, so presumably coming
321 * out of idle fixes this.
322 */
323void arch_cpu_idle_dead(void)
324{
325 unsigned int cpu = smp_processor_id();
326
327 idle_task_exit();
328
329 local_irq_disable();
330
331 /*
332 * Flush the data out of the L1 cache for this CPU. This must be
333 * before the completion to ensure that data is safely written out
334 * before platform_cpu_kill() gets called - which may disable
335 * *this* CPU and power down its cache.
336 */
337 flush_cache_louis();
338
339 /*
340 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
341 * this returns, power and/or clocks can be removed at any point
342 * from this CPU and its cache by platform_cpu_kill().
343 */
344 (void)cpu_report_death();
345
346 /*
347 * Ensure that the cache lines associated with that completion are
348 * written out. This covers the case where _this_ CPU is doing the
349 * powering down, to ensure that the completion is visible to the
350 * CPU waiting for this one.
351 */
352 flush_cache_louis();
353
354 /*
355 * The actual CPU shutdown procedure is at least platform (if not
356 * CPU) specific. This may remove power, or it may simply spin.
357 *
358 * Platforms are generally expected *NOT* to return from this call,
359 * although there are some which do because they have no way to
360 * power down the CPU. These platforms are the _only_ reason we
361 * have a return path which uses the fragment of assembly below.
362 *
363 * The return path should not be used for platforms which can
364 * power off the CPU.
365 */
366 if (smp_ops.cpu_die)
367 smp_ops.cpu_die(cpu);
368
369 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
370 cpu);
371
372 /*
373 * Do not return to the idle loop - jump back to the secondary
374 * cpu initialisation. There's some initialisation which needs
375 * to be repeated to undo the effects of taking the CPU offline.
376 */
377 __asm__("mov sp, %0\n"
378 " mov fp, #0\n"
379 " mov r0, %1\n"
380 " b secondary_start_kernel"
381 :
382 : "r" (task_stack_page(current) + THREAD_SIZE - 8),
383 "r" (current)
384 : "r0");
385}
386#endif /* CONFIG_HOTPLUG_CPU */
387
388/*
389 * Called by both boot and secondaries to move global data into
390 * per-processor storage.
391 */
392static void smp_store_cpu_info(unsigned int cpuid)
393{
394 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
395
396 cpu_info->loops_per_jiffy = loops_per_jiffy;
397 cpu_info->cpuid = read_cpuid_id();
398
399 store_cpu_topology(cpuid);
400 check_cpu_icache_size(cpuid);
401}
402
403static void set_current(struct task_struct *cur)
404{
405 /* Set TPIDRURO */
406 asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory");
407}
408
409/*
410 * This is the secondary CPU boot entry. We're using this CPUs
411 * idle thread stack, but a set of temporary page tables.
412 */
413asmlinkage void secondary_start_kernel(struct task_struct *task)
414{
415 struct mm_struct *mm = &init_mm;
416 unsigned int cpu;
417
418 set_current(task);
419
420 secondary_biglittle_init();
421
422 /*
423 * The identity mapping is uncached (strongly ordered), so
424 * switch away from it before attempting any exclusive accesses.
425 */
426 cpu_switch_mm(mm->pgd, mm);
427 local_flush_bp_all();
428 enter_lazy_tlb(mm, current);
429 local_flush_tlb_all();
430
431 /*
432 * All kernel threads share the same mm context; grab a
433 * reference and switch to it.
434 */
435 cpu = smp_processor_id();
436 mmgrab(mm);
437 current->active_mm = mm;
438 cpumask_set_cpu(cpu, mm_cpumask(mm));
439
440 cpu_init();
441
442#ifndef CONFIG_MMU
443 setup_vectors_base();
444#endif
445 pr_debug("CPU%u: Booted secondary processor\n", cpu);
446
447 trace_hardirqs_off();
448
449 /*
450 * Give the platform a chance to do its own initialisation.
451 */
452 if (smp_ops.smp_secondary_init)
453 smp_ops.smp_secondary_init(cpu);
454
455 notify_cpu_starting(cpu);
456
457 ipi_setup(cpu);
458
459 calibrate_delay();
460
461 smp_store_cpu_info(cpu);
462
463 /*
464 * OK, now it's safe to let the boot CPU continue. Wait for
465 * the CPU migration code to notice that the CPU is online
466 * before we continue - which happens after __cpu_up returns.
467 */
468 set_cpu_online(cpu, true);
469
470 check_other_bugs();
471
472 complete(&cpu_running);
473
474 local_irq_enable();
475 local_fiq_enable();
476 local_abt_enable();
477
478 /*
479 * OK, it's off to the idle thread for us
480 */
481 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
482}
483
484void __init smp_cpus_done(unsigned int max_cpus)
485{
486 int cpu;
487 unsigned long bogosum = 0;
488
489 for_each_online_cpu(cpu)
490 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
491
492 printk(KERN_INFO "SMP: Total of %d processors activated "
493 "(%lu.%02lu BogoMIPS).\n",
494 num_online_cpus(),
495 bogosum / (500000/HZ),
496 (bogosum / (5000/HZ)) % 100);
497
498 hyp_mode_check();
499}
500
501void __init smp_prepare_boot_cpu(void)
502{
503 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
504}
505
506void __init smp_prepare_cpus(unsigned int max_cpus)
507{
508 unsigned int ncores = num_possible_cpus();
509
510 init_cpu_topology();
511
512 smp_store_cpu_info(smp_processor_id());
513
514 /*
515 * are we trying to boot more cores than exist?
516 */
517 if (max_cpus > ncores)
518 max_cpus = ncores;
519 if (ncores > 1 && max_cpus) {
520 /*
521 * Initialise the present map, which describes the set of CPUs
522 * actually populated at the present time. A platform should
523 * re-initialize the map in the platforms smp_prepare_cpus()
524 * if present != possible (e.g. physical hotplug).
525 */
526 init_cpu_present(cpu_possible_mask);
527
528 /*
529 * Initialise the SCU if there are more than one CPU
530 * and let them know where to start.
531 */
532 if (smp_ops.smp_prepare_cpus)
533 smp_ops.smp_prepare_cpus(max_cpus);
534 }
535}
536
537static const char *ipi_types[NR_IPI] __tracepoint_string = {
538 [IPI_WAKEUP] = "CPU wakeup interrupts",
539 [IPI_TIMER] = "Timer broadcast interrupts",
540 [IPI_RESCHEDULE] = "Rescheduling interrupts",
541 [IPI_CALL_FUNC] = "Function call interrupts",
542 [IPI_CPU_STOP] = "CPU stop interrupts",
543 [IPI_IRQ_WORK] = "IRQ work interrupts",
544 [IPI_COMPLETION] = "completion interrupts",
545};
546
547static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
548
549void show_ipi_list(struct seq_file *p, int prec)
550{
551 unsigned int cpu, i;
552
553 for (i = 0; i < NR_IPI; i++) {
554 if (!ipi_desc[i])
555 continue;
556
557 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
558
559 for_each_online_cpu(cpu)
560 seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu));
561
562 seq_printf(p, " %s\n", ipi_types[i]);
563 }
564}
565
566void arch_send_call_function_ipi_mask(const struct cpumask *mask)
567{
568 smp_cross_call(mask, IPI_CALL_FUNC);
569}
570
571void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
572{
573 smp_cross_call(mask, IPI_WAKEUP);
574}
575
576void arch_send_call_function_single_ipi(int cpu)
577{
578 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
579}
580
581#ifdef CONFIG_IRQ_WORK
582void arch_irq_work_raise(void)
583{
584 if (arch_irq_work_has_interrupt())
585 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
586}
587#endif
588
589#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
590void tick_broadcast(const struct cpumask *mask)
591{
592 smp_cross_call(mask, IPI_TIMER);
593}
594#endif
595
596static DEFINE_RAW_SPINLOCK(stop_lock);
597
598/*
599 * ipi_cpu_stop - handle IPI from smp_send_stop()
600 */
601static void ipi_cpu_stop(unsigned int cpu)
602{
603 local_fiq_disable();
604
605 if (system_state <= SYSTEM_RUNNING) {
606 raw_spin_lock(&stop_lock);
607 pr_crit("CPU%u: stopping\n", cpu);
608 dump_stack();
609 raw_spin_unlock(&stop_lock);
610 }
611
612 set_cpu_online(cpu, false);
613
614 while (1) {
615 cpu_relax();
616 wfe();
617 }
618}
619
620static DEFINE_PER_CPU(struct completion *, cpu_completion);
621
622int register_ipi_completion(struct completion *completion, int cpu)
623{
624 per_cpu(cpu_completion, cpu) = completion;
625 return IPI_COMPLETION;
626}
627
628static void ipi_complete(unsigned int cpu)
629{
630 complete(per_cpu(cpu_completion, cpu));
631}
632
633/*
634 * Main handler for inter-processor interrupts
635 */
636static void do_handle_IPI(int ipinr)
637{
638 unsigned int cpu = smp_processor_id();
639
640 if ((unsigned)ipinr < NR_IPI)
641 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
642
643 switch (ipinr) {
644 case IPI_WAKEUP:
645 break;
646
647#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
648 case IPI_TIMER:
649 tick_receive_broadcast();
650 break;
651#endif
652
653 case IPI_RESCHEDULE:
654 scheduler_ipi();
655 break;
656
657 case IPI_CALL_FUNC:
658 generic_smp_call_function_interrupt();
659 break;
660
661 case IPI_CPU_STOP:
662 ipi_cpu_stop(cpu);
663 break;
664
665#ifdef CONFIG_IRQ_WORK
666 case IPI_IRQ_WORK:
667 irq_work_run();
668 break;
669#endif
670
671 case IPI_COMPLETION:
672 ipi_complete(cpu);
673 break;
674
675 case IPI_CPU_BACKTRACE:
676 printk_deferred_enter();
677 nmi_cpu_backtrace(get_irq_regs());
678 printk_deferred_exit();
679 break;
680
681 default:
682 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
683 cpu, ipinr);
684 break;
685 }
686
687 if ((unsigned)ipinr < NR_IPI)
688 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
689}
690
691/* Legacy version, should go away once all irqchips have been converted */
692void handle_IPI(int ipinr, struct pt_regs *regs)
693{
694 struct pt_regs *old_regs = set_irq_regs(regs);
695
696 irq_enter();
697 do_handle_IPI(ipinr);
698 irq_exit();
699
700 set_irq_regs(old_regs);
701}
702
703static irqreturn_t ipi_handler(int irq, void *data)
704{
705 do_handle_IPI(irq - ipi_irq_base);
706 return IRQ_HANDLED;
707}
708
709static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
710{
711 trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
712 __ipi_send_mask(ipi_desc[ipinr], target);
713}
714
715static void ipi_setup(int cpu)
716{
717 int i;
718
719 if (WARN_ON_ONCE(!ipi_irq_base))
720 return;
721
722 for (i = 0; i < nr_ipi; i++)
723 enable_percpu_irq(ipi_irq_base + i, 0);
724}
725
726void __init set_smp_ipi_range(int ipi_base, int n)
727{
728 int i;
729
730 WARN_ON(n < MAX_IPI);
731 nr_ipi = min(n, MAX_IPI);
732
733 for (i = 0; i < nr_ipi; i++) {
734 int err;
735
736 err = request_percpu_irq(ipi_base + i, ipi_handler,
737 "IPI", &irq_stat);
738 WARN_ON(err);
739
740 ipi_desc[i] = irq_to_desc(ipi_base + i);
741 irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
742 }
743
744 ipi_irq_base = ipi_base;
745
746 /* Setup the boot CPU immediately */
747 ipi_setup(smp_processor_id());
748}
749
750void smp_send_reschedule(int cpu)
751{
752 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
753}
754
755void smp_send_stop(void)
756{
757 unsigned long timeout;
758 struct cpumask mask;
759
760 cpumask_copy(&mask, cpu_online_mask);
761 cpumask_clear_cpu(smp_processor_id(), &mask);
762 if (!cpumask_empty(&mask))
763 smp_cross_call(&mask, IPI_CPU_STOP);
764
765 /* Wait up to one second for other CPUs to stop */
766 timeout = USEC_PER_SEC;
767 while (num_online_cpus() > 1 && timeout--)
768 udelay(1);
769
770 if (num_online_cpus() > 1)
771 pr_warn("SMP: failed to stop secondary CPUs\n");
772}
773
774/* In case panic() and panic() called at the same time on CPU1 and CPU2,
775 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
776 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
777 * kdump fails. So split out the panic_smp_self_stop() and add
778 * set_cpu_online(smp_processor_id(), false).
779 */
780void panic_smp_self_stop(void)
781{
782 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
783 smp_processor_id());
784 set_cpu_online(smp_processor_id(), false);
785 while (1)
786 cpu_relax();
787}
788
789#ifdef CONFIG_CPU_FREQ
790
791static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
792static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
793static unsigned long global_l_p_j_ref;
794static unsigned long global_l_p_j_ref_freq;
795
796static int cpufreq_callback(struct notifier_block *nb,
797 unsigned long val, void *data)
798{
799 struct cpufreq_freqs *freq = data;
800 struct cpumask *cpus = freq->policy->cpus;
801 int cpu, first = cpumask_first(cpus);
802 unsigned int lpj;
803
804 if (freq->flags & CPUFREQ_CONST_LOOPS)
805 return NOTIFY_OK;
806
807 if (!per_cpu(l_p_j_ref, first)) {
808 for_each_cpu(cpu, cpus) {
809 per_cpu(l_p_j_ref, cpu) =
810 per_cpu(cpu_data, cpu).loops_per_jiffy;
811 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
812 }
813
814 if (!global_l_p_j_ref) {
815 global_l_p_j_ref = loops_per_jiffy;
816 global_l_p_j_ref_freq = freq->old;
817 }
818 }
819
820 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
821 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
822 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
823 global_l_p_j_ref_freq,
824 freq->new);
825
826 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first),
827 per_cpu(l_p_j_ref_freq, first), freq->new);
828 for_each_cpu(cpu, cpus)
829 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj;
830 }
831 return NOTIFY_OK;
832}
833
834static struct notifier_block cpufreq_notifier = {
835 .notifier_call = cpufreq_callback,
836};
837
838static int __init register_cpufreq_notifier(void)
839{
840 return cpufreq_register_notifier(&cpufreq_notifier,
841 CPUFREQ_TRANSITION_NOTIFIER);
842}
843core_initcall(register_cpufreq_notifier);
844
845#endif
846
847static void raise_nmi(cpumask_t *mask)
848{
849 __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask);
850}
851
852void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
853{
854 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
855}