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 */
59 struct secondary_data secondary_data;
60
61 enum 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
83 static int ipi_irq_base __read_mostly;
84 static int nr_ipi __read_mostly = NR_IPI;
85 static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly;
86
87 static void ipi_setup(int cpu);
88
89 static DECLARE_COMPLETION(cpu_running);
90
91 static struct smp_operations smp_ops __ro_after_init;
92
smp_set_ops(const struct smp_operations * ops)93 void __init smp_set_ops(const struct smp_operations *ops)
94 {
95 if (ops)
96 smp_ops = *ops;
97 };
98
get_arch_pgd(pgd_t * pgd)99 static 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)
secondary_biglittle_prepare(unsigned int cpu)109 static 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
secondary_biglittle_init(void)117 static void secondary_biglittle_init(void)
118 {
119 init_proc_vtable(lookup_processor(read_cpuid_id())->proc);
120 }
121 #else
secondary_biglittle_prepare(unsigned int cpu)122 static int secondary_biglittle_prepare(unsigned int cpu)
123 {
124 return 0;
125 }
126
secondary_biglittle_init(void)127 static void secondary_biglittle_init(void)
128 {
129 }
130 #endif
131
__cpu_up(unsigned int cpu,struct task_struct * idle)132 int __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 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 */
smp_init_cpus(void)184 void __init smp_init_cpus(void)
185 {
186 if (smp_ops.smp_init_cpus)
187 smp_ops.smp_init_cpus();
188 }
189
platform_can_secondary_boot(void)190 int platform_can_secondary_boot(void)
191 {
192 return !!smp_ops.smp_boot_secondary;
193 }
194
platform_can_cpu_hotplug(void)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
platform_cpu_kill(unsigned int 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
platform_cpu_disable(unsigned int cpu)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
platform_can_hotplug_cpu(unsigned int cpu)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
ipi_teardown(int cpu)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 */
__cpu_disable(void)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 -
292 * waits until shutdown has completed, or it is timed out.
293 */
__cpu_die(unsigned int cpu)294 void __cpu_die(unsigned int cpu)
295 {
296 if (!cpu_wait_death(cpu, 5)) {
297 pr_err("CPU%u: cpu didn't die\n", cpu);
298 return;
299 }
300 pr_debug("CPU%u: shutdown\n", cpu);
301
302 clear_tasks_mm_cpumask(cpu);
303 /*
304 * platform_cpu_kill() is generally expected to do the powering off
305 * and/or cutting of clocks to the dying CPU. Optionally, this may
306 * be done by the CPU which is dying in preference to supporting
307 * this call, but that means there is _no_ synchronisation between
308 * the requesting CPU and the dying CPU actually losing power.
309 */
310 if (!platform_cpu_kill(cpu))
311 pr_err("CPU%u: unable to kill\n", cpu);
312 }
313
314 /*
315 * Called from the idle thread for the CPU which has been shutdown.
316 *
317 * Note that we disable IRQs here, but do not re-enable them
318 * before returning to the caller. This is also the behaviour
319 * of the other hotplug-cpu capable cores, so presumably coming
320 * out of idle fixes this.
321 */
arch_cpu_idle_dead(void)322 void arch_cpu_idle_dead(void)
323 {
324 unsigned int cpu = smp_processor_id();
325
326 idle_task_exit();
327
328 local_irq_disable();
329
330 /*
331 * Flush the data out of the L1 cache for this CPU. This must be
332 * before the completion to ensure that data is safely written out
333 * before platform_cpu_kill() gets called - which may disable
334 * *this* CPU and power down its cache.
335 */
336 flush_cache_louis();
337
338 /*
339 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
340 * this returns, power and/or clocks can be removed at any point
341 * from this CPU and its cache by platform_cpu_kill().
342 */
343 (void)cpu_report_death();
344
345 /*
346 * Ensure that the cache lines associated with that completion are
347 * written out. This covers the case where _this_ CPU is doing the
348 * powering down, to ensure that the completion is visible to the
349 * CPU waiting for this one.
350 */
351 flush_cache_louis();
352
353 /*
354 * The actual CPU shutdown procedure is at least platform (if not
355 * CPU) specific. This may remove power, or it may simply spin.
356 *
357 * Platforms are generally expected *NOT* to return from this call,
358 * although there are some which do because they have no way to
359 * power down the CPU. These platforms are the _only_ reason we
360 * have a return path which uses the fragment of assembly below.
361 *
362 * The return path should not be used for platforms which can
363 * power off the CPU.
364 */
365 if (smp_ops.cpu_die)
366 smp_ops.cpu_die(cpu);
367
368 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
369 cpu);
370
371 /*
372 * Do not return to the idle loop - jump back to the secondary
373 * cpu initialisation. There's some initialisation which needs
374 * to be repeated to undo the effects of taking the CPU offline.
375 */
376 __asm__("mov sp, %0\n"
377 " mov fp, #0\n"
378 " b secondary_start_kernel"
379 :
380 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
381 }
382 #endif /* CONFIG_HOTPLUG_CPU */
383
384 /*
385 * Called by both boot and secondaries to move global data into
386 * per-processor storage.
387 */
smp_store_cpu_info(unsigned int cpuid)388 static void smp_store_cpu_info(unsigned int cpuid)
389 {
390 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
391
392 cpu_info->loops_per_jiffy = loops_per_jiffy;
393 cpu_info->cpuid = read_cpuid_id();
394
395 store_cpu_topology(cpuid);
396 check_cpu_icache_size(cpuid);
397 }
398
399 /*
400 * This is the secondary CPU boot entry. We're using this CPUs
401 * idle thread stack, but a set of temporary page tables.
402 */
secondary_start_kernel(void)403 asmlinkage void secondary_start_kernel(void)
404 {
405 struct mm_struct *mm = &init_mm;
406 unsigned int cpu;
407
408 secondary_biglittle_init();
409
410 /*
411 * The identity mapping is uncached (strongly ordered), so
412 * switch away from it before attempting any exclusive accesses.
413 */
414 cpu_switch_mm(mm->pgd, mm);
415 local_flush_bp_all();
416 enter_lazy_tlb(mm, current);
417 local_flush_tlb_all();
418
419 /*
420 * All kernel threads share the same mm context; grab a
421 * reference and switch to it.
422 */
423 cpu = smp_processor_id();
424 mmgrab(mm);
425 current->active_mm = mm;
426 cpumask_set_cpu(cpu, mm_cpumask(mm));
427
428 cpu_init();
429
430 #ifndef CONFIG_MMU
431 setup_vectors_base();
432 #endif
433 pr_debug("CPU%u: Booted secondary processor\n", cpu);
434
435 preempt_disable();
436 trace_hardirqs_off();
437
438 /*
439 * Give the platform a chance to do its own initialisation.
440 */
441 if (smp_ops.smp_secondary_init)
442 smp_ops.smp_secondary_init(cpu);
443
444 notify_cpu_starting(cpu);
445
446 ipi_setup(cpu);
447
448 calibrate_delay();
449
450 smp_store_cpu_info(cpu);
451
452 /*
453 * OK, now it's safe to let the boot CPU continue. Wait for
454 * the CPU migration code to notice that the CPU is online
455 * before we continue - which happens after __cpu_up returns.
456 */
457 set_cpu_online(cpu, true);
458
459 check_other_bugs();
460
461 complete(&cpu_running);
462
463 local_irq_enable();
464 local_fiq_enable();
465 local_abt_enable();
466
467 /*
468 * OK, it's off to the idle thread for us
469 */
470 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
471 }
472
smp_cpus_done(unsigned int max_cpus)473 void __init smp_cpus_done(unsigned int max_cpus)
474 {
475 int cpu;
476 unsigned long bogosum = 0;
477
478 for_each_online_cpu(cpu)
479 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
480
481 printk(KERN_INFO "SMP: Total of %d processors activated "
482 "(%lu.%02lu BogoMIPS).\n",
483 num_online_cpus(),
484 bogosum / (500000/HZ),
485 (bogosum / (5000/HZ)) % 100);
486
487 hyp_mode_check();
488 }
489
smp_prepare_boot_cpu(void)490 void __init smp_prepare_boot_cpu(void)
491 {
492 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
493 }
494
smp_prepare_cpus(unsigned int max_cpus)495 void __init smp_prepare_cpus(unsigned int max_cpus)
496 {
497 unsigned int ncores = num_possible_cpus();
498
499 init_cpu_topology();
500
501 smp_store_cpu_info(smp_processor_id());
502
503 /*
504 * are we trying to boot more cores than exist?
505 */
506 if (max_cpus > ncores)
507 max_cpus = ncores;
508 if (ncores > 1 && max_cpus) {
509 /*
510 * Initialise the present map, which describes the set of CPUs
511 * actually populated at the present time. A platform should
512 * re-initialize the map in the platforms smp_prepare_cpus()
513 * if present != possible (e.g. physical hotplug).
514 */
515 init_cpu_present(cpu_possible_mask);
516
517 /*
518 * Initialise the SCU if there are more than one CPU
519 * and let them know where to start.
520 */
521 if (smp_ops.smp_prepare_cpus)
522 smp_ops.smp_prepare_cpus(max_cpus);
523 }
524 }
525
526 static const char *ipi_types[NR_IPI] __tracepoint_string = {
527 #define S(x,s) [x] = s
528 S(IPI_WAKEUP, "CPU wakeup interrupts"),
529 S(IPI_TIMER, "Timer broadcast interrupts"),
530 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
531 S(IPI_CALL_FUNC, "Function call interrupts"),
532 S(IPI_CPU_STOP, "CPU stop interrupts"),
533 S(IPI_IRQ_WORK, "IRQ work interrupts"),
534 S(IPI_COMPLETION, "completion interrupts"),
535 };
536
537 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
538
show_ipi_list(struct seq_file * p,int prec)539 void show_ipi_list(struct seq_file *p, int prec)
540 {
541 unsigned int cpu, i;
542
543 for (i = 0; i < NR_IPI; i++) {
544 unsigned int irq;
545
546 if (!ipi_desc[i])
547 continue;
548
549 irq = irq_desc_get_irq(ipi_desc[i]);
550 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
551
552 for_each_online_cpu(cpu)
553 seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
554
555 seq_printf(p, " %s\n", ipi_types[i]);
556 }
557 }
558
arch_send_call_function_ipi_mask(const struct cpumask * mask)559 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
560 {
561 smp_cross_call(mask, IPI_CALL_FUNC);
562 }
563
arch_send_wakeup_ipi_mask(const struct cpumask * mask)564 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
565 {
566 smp_cross_call(mask, IPI_WAKEUP);
567 }
568
arch_send_call_function_single_ipi(int cpu)569 void arch_send_call_function_single_ipi(int cpu)
570 {
571 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
572 }
573
574 #ifdef CONFIG_IRQ_WORK
arch_irq_work_raise(void)575 void arch_irq_work_raise(void)
576 {
577 if (arch_irq_work_has_interrupt())
578 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
579 }
580 #endif
581
582 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
tick_broadcast(const struct cpumask * mask)583 void tick_broadcast(const struct cpumask *mask)
584 {
585 smp_cross_call(mask, IPI_TIMER);
586 }
587 #endif
588
589 static DEFINE_RAW_SPINLOCK(stop_lock);
590
591 /*
592 * ipi_cpu_stop - handle IPI from smp_send_stop()
593 */
ipi_cpu_stop(unsigned int cpu)594 static void ipi_cpu_stop(unsigned int cpu)
595 {
596 if (system_state <= SYSTEM_RUNNING) {
597 raw_spin_lock(&stop_lock);
598 pr_crit("CPU%u: stopping\n", cpu);
599 dump_stack();
600 raw_spin_unlock(&stop_lock);
601 }
602
603 set_cpu_online(cpu, false);
604
605 local_fiq_disable();
606 local_irq_disable();
607
608 while (1) {
609 cpu_relax();
610 wfe();
611 }
612 }
613
614 static DEFINE_PER_CPU(struct completion *, cpu_completion);
615
register_ipi_completion(struct completion * completion,int cpu)616 int register_ipi_completion(struct completion *completion, int cpu)
617 {
618 per_cpu(cpu_completion, cpu) = completion;
619 return IPI_COMPLETION;
620 }
621
ipi_complete(unsigned int cpu)622 static void ipi_complete(unsigned int cpu)
623 {
624 complete(per_cpu(cpu_completion, cpu));
625 }
626
627 /*
628 * Main handler for inter-processor interrupts
629 */
do_IPI(int ipinr,struct pt_regs * regs)630 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
631 {
632 handle_IPI(ipinr, regs);
633 }
634
do_handle_IPI(int ipinr)635 static void do_handle_IPI(int ipinr)
636 {
637 unsigned int cpu = smp_processor_id();
638
639 if ((unsigned)ipinr < NR_IPI)
640 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
641
642 switch (ipinr) {
643 case IPI_WAKEUP:
644 break;
645
646 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
647 case IPI_TIMER:
648 tick_receive_broadcast();
649 break;
650 #endif
651
652 case IPI_RESCHEDULE:
653 scheduler_ipi();
654 break;
655
656 case IPI_CALL_FUNC:
657 generic_smp_call_function_interrupt();
658 break;
659
660 case IPI_CPU_STOP:
661 ipi_cpu_stop(cpu);
662 break;
663
664 #ifdef CONFIG_IRQ_WORK
665 case IPI_IRQ_WORK:
666 irq_work_run();
667 break;
668 #endif
669
670 case IPI_COMPLETION:
671 ipi_complete(cpu);
672 break;
673
674 case IPI_CPU_BACKTRACE:
675 printk_nmi_enter();
676 nmi_cpu_backtrace(get_irq_regs());
677 printk_nmi_exit();
678 break;
679
680 default:
681 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
682 cpu, ipinr);
683 break;
684 }
685
686 if ((unsigned)ipinr < NR_IPI)
687 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
688 }
689
690 /* Legacy version, should go away once all irqchips have been converted */
handle_IPI(int ipinr,struct pt_regs * regs)691 void handle_IPI(int ipinr, struct pt_regs *regs)
692 {
693 struct pt_regs *old_regs = set_irq_regs(regs);
694
695 irq_enter();
696 do_handle_IPI(ipinr);
697 irq_exit();
698
699 set_irq_regs(old_regs);
700 }
701
ipi_handler(int irq,void * data)702 static irqreturn_t ipi_handler(int irq, void *data)
703 {
704 do_handle_IPI(irq - ipi_irq_base);
705 return IRQ_HANDLED;
706 }
707
smp_cross_call(const struct cpumask * target,unsigned int ipinr)708 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
709 {
710 trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
711 __ipi_send_mask(ipi_desc[ipinr], target);
712 }
713
ipi_setup(int cpu)714 static void ipi_setup(int cpu)
715 {
716 int i;
717
718 if (WARN_ON_ONCE(!ipi_irq_base))
719 return;
720
721 for (i = 0; i < nr_ipi; i++)
722 enable_percpu_irq(ipi_irq_base + i, 0);
723 }
724
set_smp_ipi_range(int ipi_base,int n)725 void __init set_smp_ipi_range(int ipi_base, int n)
726 {
727 int i;
728
729 WARN_ON(n < MAX_IPI);
730 nr_ipi = min(n, MAX_IPI);
731
732 for (i = 0; i < nr_ipi; i++) {
733 int err;
734
735 err = request_percpu_irq(ipi_base + i, ipi_handler,
736 "IPI", &irq_stat);
737 WARN_ON(err);
738
739 ipi_desc[i] = irq_to_desc(ipi_base + i);
740 irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
741 }
742
743 ipi_irq_base = ipi_base;
744
745 /* Setup the boot CPU immediately */
746 ipi_setup(smp_processor_id());
747 }
748
smp_send_reschedule(int cpu)749 void smp_send_reschedule(int cpu)
750 {
751 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
752 }
753
smp_send_stop(void)754 void smp_send_stop(void)
755 {
756 unsigned long timeout;
757 struct cpumask mask;
758
759 cpumask_copy(&mask, cpu_online_mask);
760 cpumask_clear_cpu(smp_processor_id(), &mask);
761 if (!cpumask_empty(&mask))
762 smp_cross_call(&mask, IPI_CPU_STOP);
763
764 /* Wait up to one second for other CPUs to stop */
765 timeout = USEC_PER_SEC;
766 while (num_online_cpus() > 1 && timeout--)
767 udelay(1);
768
769 if (num_online_cpus() > 1)
770 pr_warn("SMP: failed to stop secondary CPUs\n");
771 }
772
773 /* In case panic() and panic() called at the same time on CPU1 and CPU2,
774 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
775 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
776 * kdump fails. So split out the panic_smp_self_stop() and add
777 * set_cpu_online(smp_processor_id(), false).
778 */
panic_smp_self_stop(void)779 void panic_smp_self_stop(void)
780 {
781 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
782 smp_processor_id());
783 set_cpu_online(smp_processor_id(), false);
784 while (1)
785 cpu_relax();
786 }
787
788 /*
789 * not supported here
790 */
setup_profiling_timer(unsigned int multiplier)791 int setup_profiling_timer(unsigned int multiplier)
792 {
793 return -EINVAL;
794 }
795
796 #ifdef CONFIG_CPU_FREQ
797
798 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
799 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
800 static unsigned long global_l_p_j_ref;
801 static unsigned long global_l_p_j_ref_freq;
802
cpufreq_callback(struct notifier_block * nb,unsigned long val,void * data)803 static int cpufreq_callback(struct notifier_block *nb,
804 unsigned long val, void *data)
805 {
806 struct cpufreq_freqs *freq = data;
807 struct cpumask *cpus = freq->policy->cpus;
808 int cpu, first = cpumask_first(cpus);
809 unsigned int lpj;
810
811 if (freq->flags & CPUFREQ_CONST_LOOPS)
812 return NOTIFY_OK;
813
814 if (!per_cpu(l_p_j_ref, first)) {
815 for_each_cpu(cpu, cpus) {
816 per_cpu(l_p_j_ref, cpu) =
817 per_cpu(cpu_data, cpu).loops_per_jiffy;
818 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
819 }
820
821 if (!global_l_p_j_ref) {
822 global_l_p_j_ref = loops_per_jiffy;
823 global_l_p_j_ref_freq = freq->old;
824 }
825 }
826
827 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
828 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
829 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
830 global_l_p_j_ref_freq,
831 freq->new);
832
833 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first),
834 per_cpu(l_p_j_ref_freq, first), freq->new);
835 for_each_cpu(cpu, cpus)
836 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj;
837 }
838 return NOTIFY_OK;
839 }
840
841 static struct notifier_block cpufreq_notifier = {
842 .notifier_call = cpufreq_callback,
843 };
844
register_cpufreq_notifier(void)845 static int __init register_cpufreq_notifier(void)
846 {
847 return cpufreq_register_notifier(&cpufreq_notifier,
848 CPUFREQ_TRANSITION_NOTIFIER);
849 }
850 core_initcall(register_cpufreq_notifier);
851
852 #endif
853
raise_nmi(cpumask_t * mask)854 static void raise_nmi(cpumask_t *mask)
855 {
856 __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask);
857 }
858
arch_trigger_cpumask_backtrace(const cpumask_t * mask,bool exclude_self)859 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
860 {
861 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
862 }
863