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