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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/smp.h>
23#include <linux/seq_file.h>
24#include <linux/irq.h>
25#include <linux/percpu.h>
26#include <linux/clockchips.h>
27#include <linux/completion.h>
28
29#include <linux/atomic.h>
30#include <asm/cacheflush.h>
31#include <asm/cpu.h>
32#include <asm/cputype.h>
33#include <asm/exception.h>
34#include <asm/idmap.h>
35#include <asm/topology.h>
36#include <asm/mmu_context.h>
37#include <asm/pgtable.h>
38#include <asm/pgalloc.h>
39#include <asm/processor.h>
40#include <asm/sections.h>
41#include <asm/tlbflush.h>
42#include <asm/ptrace.h>
43#include <asm/localtimer.h>
44#include <asm/smp_plat.h>
45
46/*
47 * as from 2.5, kernels no longer have an init_tasks structure
48 * so we need some other way of telling a new secondary core
49 * where to place its SVC stack
50 */
51struct secondary_data secondary_data;
52
53enum ipi_msg_type {
54 IPI_TIMER = 2,
55 IPI_RESCHEDULE,
56 IPI_CALL_FUNC,
57 IPI_CALL_FUNC_SINGLE,
58 IPI_CPU_STOP,
59};
60
61static DECLARE_COMPLETION(cpu_running);
62
63int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
64{
65 int ret;
66
67 /*
68 * We need to tell the secondary core where to find
69 * its stack and the page tables.
70 */
71 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
72 secondary_data.pgdir = virt_to_phys(idmap_pgd);
73 secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
74 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
75 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
76
77 /*
78 * Now bring the CPU into our world.
79 */
80 ret = boot_secondary(cpu, idle);
81 if (ret == 0) {
82 /*
83 * CPU was successfully started, wait for it
84 * to come online or time out.
85 */
86 wait_for_completion_timeout(&cpu_running,
87 msecs_to_jiffies(1000));
88
89 if (!cpu_online(cpu)) {
90 pr_crit("CPU%u: failed to come online\n", cpu);
91 ret = -EIO;
92 }
93 } else {
94 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
95 }
96
97 secondary_data.stack = NULL;
98 secondary_data.pgdir = 0;
99
100 return ret;
101}
102
103#ifdef CONFIG_HOTPLUG_CPU
104static void percpu_timer_stop(void);
105
106/*
107 * __cpu_disable runs on the processor to be shutdown.
108 */
109int __cpu_disable(void)
110{
111 unsigned int cpu = smp_processor_id();
112 int ret;
113
114 ret = platform_cpu_disable(cpu);
115 if (ret)
116 return ret;
117
118 /*
119 * Take this CPU offline. Once we clear this, we can't return,
120 * and we must not schedule until we're ready to give up the cpu.
121 */
122 set_cpu_online(cpu, false);
123
124 /*
125 * OK - migrate IRQs away from this CPU
126 */
127 migrate_irqs();
128
129 /*
130 * Stop the local timer for this CPU.
131 */
132 percpu_timer_stop();
133
134 /*
135 * Flush user cache and TLB mappings, and then remove this CPU
136 * from the vm mask set of all processes.
137 */
138 flush_cache_all();
139 local_flush_tlb_all();
140
141 clear_tasks_mm_cpumask(cpu);
142
143 return 0;
144}
145
146static DECLARE_COMPLETION(cpu_died);
147
148/*
149 * called on the thread which is asking for a CPU to be shutdown -
150 * waits until shutdown has completed, or it is timed out.
151 */
152void __cpu_die(unsigned int cpu)
153{
154 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
155 pr_err("CPU%u: cpu didn't die\n", cpu);
156 return;
157 }
158 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
159
160 if (!platform_cpu_kill(cpu))
161 printk("CPU%u: unable to kill\n", cpu);
162}
163
164/*
165 * Called from the idle thread for the CPU which has been shutdown.
166 *
167 * Note that we disable IRQs here, but do not re-enable them
168 * before returning to the caller. This is also the behaviour
169 * of the other hotplug-cpu capable cores, so presumably coming
170 * out of idle fixes this.
171 */
172void __ref cpu_die(void)
173{
174 unsigned int cpu = smp_processor_id();
175
176 idle_task_exit();
177
178 local_irq_disable();
179 mb();
180
181 /* Tell __cpu_die() that this CPU is now safe to dispose of */
182 complete(&cpu_died);
183
184 /*
185 * actual CPU shutdown procedure is at least platform (if not
186 * CPU) specific.
187 */
188 platform_cpu_die(cpu);
189
190 /*
191 * Do not return to the idle loop - jump back to the secondary
192 * cpu initialisation. There's some initialisation which needs
193 * to be repeated to undo the effects of taking the CPU offline.
194 */
195 __asm__("mov sp, %0\n"
196 " mov fp, #0\n"
197 " b secondary_start_kernel"
198 :
199 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
200}
201#endif /* CONFIG_HOTPLUG_CPU */
202
203/*
204 * Called by both boot and secondaries to move global data into
205 * per-processor storage.
206 */
207static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
208{
209 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
210
211 cpu_info->loops_per_jiffy = loops_per_jiffy;
212
213 store_cpu_topology(cpuid);
214}
215
216static void percpu_timer_setup(void);
217
218/*
219 * This is the secondary CPU boot entry. We're using this CPUs
220 * idle thread stack, but a set of temporary page tables.
221 */
222asmlinkage void __cpuinit secondary_start_kernel(void)
223{
224 struct mm_struct *mm = &init_mm;
225 unsigned int cpu = smp_processor_id();
226
227 /*
228 * All kernel threads share the same mm context; grab a
229 * reference and switch to it.
230 */
231 atomic_inc(&mm->mm_count);
232 current->active_mm = mm;
233 cpumask_set_cpu(cpu, mm_cpumask(mm));
234 cpu_switch_mm(mm->pgd, mm);
235 enter_lazy_tlb(mm, current);
236 local_flush_tlb_all();
237
238 printk("CPU%u: Booted secondary processor\n", cpu);
239
240 cpu_init();
241 preempt_disable();
242 trace_hardirqs_off();
243
244 /*
245 * Give the platform a chance to do its own initialisation.
246 */
247 platform_secondary_init(cpu);
248
249 notify_cpu_starting(cpu);
250
251 calibrate_delay();
252
253 smp_store_cpu_info(cpu);
254
255 /*
256 * OK, now it's safe to let the boot CPU continue. Wait for
257 * the CPU migration code to notice that the CPU is online
258 * before we continue - which happens after __cpu_up returns.
259 */
260 set_cpu_online(cpu, true);
261 complete(&cpu_running);
262
263 /*
264 * Setup the percpu timer for this CPU.
265 */
266 percpu_timer_setup();
267
268 local_irq_enable();
269 local_fiq_enable();
270
271 /*
272 * OK, it's off to the idle thread for us
273 */
274 cpu_idle();
275}
276
277void __init smp_cpus_done(unsigned int max_cpus)
278{
279 int cpu;
280 unsigned long bogosum = 0;
281
282 for_each_online_cpu(cpu)
283 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
284
285 printk(KERN_INFO "SMP: Total of %d processors activated "
286 "(%lu.%02lu BogoMIPS).\n",
287 num_online_cpus(),
288 bogosum / (500000/HZ),
289 (bogosum / (5000/HZ)) % 100);
290}
291
292void __init smp_prepare_boot_cpu(void)
293{
294}
295
296void __init smp_prepare_cpus(unsigned int max_cpus)
297{
298 unsigned int ncores = num_possible_cpus();
299
300 init_cpu_topology();
301
302 smp_store_cpu_info(smp_processor_id());
303
304 /*
305 * are we trying to boot more cores than exist?
306 */
307 if (max_cpus > ncores)
308 max_cpus = ncores;
309 if (ncores > 1 && max_cpus) {
310 /*
311 * Enable the local timer or broadcast device for the
312 * boot CPU, but only if we have more than one CPU.
313 */
314 percpu_timer_setup();
315
316 /*
317 * Initialise the present map, which describes the set of CPUs
318 * actually populated at the present time. A platform should
319 * re-initialize the map in platform_smp_prepare_cpus() if
320 * present != possible (e.g. physical hotplug).
321 */
322 init_cpu_present(cpu_possible_mask);
323
324 /*
325 * Initialise the SCU if there are more than one CPU
326 * and let them know where to start.
327 */
328 platform_smp_prepare_cpus(max_cpus);
329 }
330}
331
332static void (*smp_cross_call)(const struct cpumask *, unsigned int);
333
334void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
335{
336 smp_cross_call = fn;
337}
338
339void arch_send_call_function_ipi_mask(const struct cpumask *mask)
340{
341 smp_cross_call(mask, IPI_CALL_FUNC);
342}
343
344void arch_send_call_function_single_ipi(int cpu)
345{
346 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
347}
348
349static const char *ipi_types[NR_IPI] = {
350#define S(x,s) [x - IPI_TIMER] = s
351 S(IPI_TIMER, "Timer broadcast interrupts"),
352 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
353 S(IPI_CALL_FUNC, "Function call interrupts"),
354 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
355 S(IPI_CPU_STOP, "CPU stop interrupts"),
356};
357
358void show_ipi_list(struct seq_file *p, int prec)
359{
360 unsigned int cpu, i;
361
362 for (i = 0; i < NR_IPI; i++) {
363 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
364
365 for_each_present_cpu(cpu)
366 seq_printf(p, "%10u ",
367 __get_irq_stat(cpu, ipi_irqs[i]));
368
369 seq_printf(p, " %s\n", ipi_types[i]);
370 }
371}
372
373u64 smp_irq_stat_cpu(unsigned int cpu)
374{
375 u64 sum = 0;
376 int i;
377
378 for (i = 0; i < NR_IPI; i++)
379 sum += __get_irq_stat(cpu, ipi_irqs[i]);
380
381 return sum;
382}
383
384/*
385 * Timer (local or broadcast) support
386 */
387static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
388
389static void ipi_timer(void)
390{
391 struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
392 evt->event_handler(evt);
393}
394
395#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
396static void smp_timer_broadcast(const struct cpumask *mask)
397{
398 smp_cross_call(mask, IPI_TIMER);
399}
400#else
401#define smp_timer_broadcast NULL
402#endif
403
404static void broadcast_timer_set_mode(enum clock_event_mode mode,
405 struct clock_event_device *evt)
406{
407}
408
409static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
410{
411 evt->name = "dummy_timer";
412 evt->features = CLOCK_EVT_FEAT_ONESHOT |
413 CLOCK_EVT_FEAT_PERIODIC |
414 CLOCK_EVT_FEAT_DUMMY;
415 evt->rating = 400;
416 evt->mult = 1;
417 evt->set_mode = broadcast_timer_set_mode;
418
419 clockevents_register_device(evt);
420}
421
422static struct local_timer_ops *lt_ops;
423
424#ifdef CONFIG_LOCAL_TIMERS
425int local_timer_register(struct local_timer_ops *ops)
426{
427 if (!is_smp() || !setup_max_cpus)
428 return -ENXIO;
429
430 if (lt_ops)
431 return -EBUSY;
432
433 lt_ops = ops;
434 return 0;
435}
436#endif
437
438static void __cpuinit percpu_timer_setup(void)
439{
440 unsigned int cpu = smp_processor_id();
441 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
442
443 evt->cpumask = cpumask_of(cpu);
444 evt->broadcast = smp_timer_broadcast;
445
446 if (!lt_ops || lt_ops->setup(evt))
447 broadcast_timer_setup(evt);
448}
449
450#ifdef CONFIG_HOTPLUG_CPU
451/*
452 * The generic clock events code purposely does not stop the local timer
453 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
454 * manually here.
455 */
456static void percpu_timer_stop(void)
457{
458 unsigned int cpu = smp_processor_id();
459 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
460
461 if (lt_ops)
462 lt_ops->stop(evt);
463}
464#endif
465
466static DEFINE_RAW_SPINLOCK(stop_lock);
467
468/*
469 * ipi_cpu_stop - handle IPI from smp_send_stop()
470 */
471static void ipi_cpu_stop(unsigned int cpu)
472{
473 if (system_state == SYSTEM_BOOTING ||
474 system_state == SYSTEM_RUNNING) {
475 raw_spin_lock(&stop_lock);
476 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
477 dump_stack();
478 raw_spin_unlock(&stop_lock);
479 }
480
481 set_cpu_online(cpu, false);
482
483 local_fiq_disable();
484 local_irq_disable();
485
486 while (1)
487 cpu_relax();
488}
489
490/*
491 * Main handler for inter-processor interrupts
492 */
493asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
494{
495 handle_IPI(ipinr, regs);
496}
497
498void handle_IPI(int ipinr, struct pt_regs *regs)
499{
500 unsigned int cpu = smp_processor_id();
501 struct pt_regs *old_regs = set_irq_regs(regs);
502
503 if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI)
504 __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]);
505
506 switch (ipinr) {
507 case IPI_TIMER:
508 irq_enter();
509 ipi_timer();
510 irq_exit();
511 break;
512
513 case IPI_RESCHEDULE:
514 scheduler_ipi();
515 break;
516
517 case IPI_CALL_FUNC:
518 irq_enter();
519 generic_smp_call_function_interrupt();
520 irq_exit();
521 break;
522
523 case IPI_CALL_FUNC_SINGLE:
524 irq_enter();
525 generic_smp_call_function_single_interrupt();
526 irq_exit();
527 break;
528
529 case IPI_CPU_STOP:
530 irq_enter();
531 ipi_cpu_stop(cpu);
532 irq_exit();
533 break;
534
535 default:
536 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
537 cpu, ipinr);
538 break;
539 }
540 set_irq_regs(old_regs);
541}
542
543void smp_send_reschedule(int cpu)
544{
545 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
546}
547
548#ifdef CONFIG_HOTPLUG_CPU
549static void smp_kill_cpus(cpumask_t *mask)
550{
551 unsigned int cpu;
552 for_each_cpu(cpu, mask)
553 platform_cpu_kill(cpu);
554}
555#else
556static void smp_kill_cpus(cpumask_t *mask) { }
557#endif
558
559void smp_send_stop(void)
560{
561 unsigned long timeout;
562 struct cpumask mask;
563
564 cpumask_copy(&mask, cpu_online_mask);
565 cpumask_clear_cpu(smp_processor_id(), &mask);
566 if (!cpumask_empty(&mask))
567 smp_cross_call(&mask, IPI_CPU_STOP);
568
569 /* Wait up to one second for other CPUs to stop */
570 timeout = USEC_PER_SEC;
571 while (num_online_cpus() > 1 && timeout--)
572 udelay(1);
573
574 if (num_online_cpus() > 1)
575 pr_warning("SMP: failed to stop secondary CPUs\n");
576
577 smp_kill_cpus(&mask);
578}
579
580/*
581 * not supported here
582 */
583int setup_profiling_timer(unsigned int multiplier)
584{
585 return -EINVAL;
586}
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 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 */
184void __init smp_init_cpus(void)
185{
186 if (smp_ops.smp_init_cpus)
187 smp_ops.smp_init_cpus();
188}
189
190int platform_can_secondary_boot(void)
191{
192 return !!smp_ops.smp_boot_secondary;
193}
194
195int 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
206static 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
213static 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
221int 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
238static 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 */
252int __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 */
294void __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 */
322void 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 */
388static 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 */
403asmlinkage 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 trace_hardirqs_off();
436
437 /*
438 * Give the platform a chance to do its own initialisation.
439 */
440 if (smp_ops.smp_secondary_init)
441 smp_ops.smp_secondary_init(cpu);
442
443 notify_cpu_starting(cpu);
444
445 ipi_setup(cpu);
446
447 calibrate_delay();
448
449 smp_store_cpu_info(cpu);
450
451 /*
452 * OK, now it's safe to let the boot CPU continue. Wait for
453 * the CPU migration code to notice that the CPU is online
454 * before we continue - which happens after __cpu_up returns.
455 */
456 set_cpu_online(cpu, true);
457
458 check_other_bugs();
459
460 complete(&cpu_running);
461
462 local_irq_enable();
463 local_fiq_enable();
464 local_abt_enable();
465
466 /*
467 * OK, it's off to the idle thread for us
468 */
469 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
470}
471
472void __init smp_cpus_done(unsigned int max_cpus)
473{
474 int cpu;
475 unsigned long bogosum = 0;
476
477 for_each_online_cpu(cpu)
478 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
479
480 printk(KERN_INFO "SMP: Total of %d processors activated "
481 "(%lu.%02lu BogoMIPS).\n",
482 num_online_cpus(),
483 bogosum / (500000/HZ),
484 (bogosum / (5000/HZ)) % 100);
485
486 hyp_mode_check();
487}
488
489void __init smp_prepare_boot_cpu(void)
490{
491 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
492}
493
494void __init smp_prepare_cpus(unsigned int max_cpus)
495{
496 unsigned int ncores = num_possible_cpus();
497
498 init_cpu_topology();
499
500 smp_store_cpu_info(smp_processor_id());
501
502 /*
503 * are we trying to boot more cores than exist?
504 */
505 if (max_cpus > ncores)
506 max_cpus = ncores;
507 if (ncores > 1 && max_cpus) {
508 /*
509 * Initialise the present map, which describes the set of CPUs
510 * actually populated at the present time. A platform should
511 * re-initialize the map in the platforms smp_prepare_cpus()
512 * if present != possible (e.g. physical hotplug).
513 */
514 init_cpu_present(cpu_possible_mask);
515
516 /*
517 * Initialise the SCU if there are more than one CPU
518 * and let them know where to start.
519 */
520 if (smp_ops.smp_prepare_cpus)
521 smp_ops.smp_prepare_cpus(max_cpus);
522 }
523}
524
525static const char *ipi_types[NR_IPI] __tracepoint_string = {
526 [IPI_WAKEUP] = "CPU wakeup interrupts",
527 [IPI_TIMER] = "Timer broadcast interrupts",
528 [IPI_RESCHEDULE] = "Rescheduling interrupts",
529 [IPI_CALL_FUNC] = "Function call interrupts",
530 [IPI_CPU_STOP] = "CPU stop interrupts",
531 [IPI_IRQ_WORK] = "IRQ work interrupts",
532 [IPI_COMPLETION] = "completion interrupts",
533};
534
535static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
536
537void show_ipi_list(struct seq_file *p, int prec)
538{
539 unsigned int cpu, i;
540
541 for (i = 0; i < NR_IPI; i++) {
542 if (!ipi_desc[i])
543 continue;
544
545 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
546
547 for_each_online_cpu(cpu)
548 seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu));
549
550 seq_printf(p, " %s\n", ipi_types[i]);
551 }
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
630static void do_handle_IPI(int ipinr)
631{
632 unsigned int cpu = smp_processor_id();
633
634 if ((unsigned)ipinr < NR_IPI)
635 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
636
637 switch (ipinr) {
638 case IPI_WAKEUP:
639 break;
640
641#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
642 case IPI_TIMER:
643 tick_receive_broadcast();
644 break;
645#endif
646
647 case IPI_RESCHEDULE:
648 scheduler_ipi();
649 break;
650
651 case IPI_CALL_FUNC:
652 generic_smp_call_function_interrupt();
653 break;
654
655 case IPI_CPU_STOP:
656 ipi_cpu_stop(cpu);
657 break;
658
659#ifdef CONFIG_IRQ_WORK
660 case IPI_IRQ_WORK:
661 irq_work_run();
662 break;
663#endif
664
665 case IPI_COMPLETION:
666 ipi_complete(cpu);
667 break;
668
669 case IPI_CPU_BACKTRACE:
670 printk_nmi_enter();
671 nmi_cpu_backtrace(get_irq_regs());
672 printk_nmi_exit();
673 break;
674
675 default:
676 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
677 cpu, ipinr);
678 break;
679 }
680
681 if ((unsigned)ipinr < NR_IPI)
682 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
683}
684
685/* Legacy version, should go away once all irqchips have been converted */
686void handle_IPI(int ipinr, struct pt_regs *regs)
687{
688 struct pt_regs *old_regs = set_irq_regs(regs);
689
690 irq_enter();
691 do_handle_IPI(ipinr);
692 irq_exit();
693
694 set_irq_regs(old_regs);
695}
696
697static irqreturn_t ipi_handler(int irq, void *data)
698{
699 do_handle_IPI(irq - ipi_irq_base);
700 return IRQ_HANDLED;
701}
702
703static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
704{
705 trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
706 __ipi_send_mask(ipi_desc[ipinr], target);
707}
708
709static void ipi_setup(int cpu)
710{
711 int i;
712
713 if (WARN_ON_ONCE(!ipi_irq_base))
714 return;
715
716 for (i = 0; i < nr_ipi; i++)
717 enable_percpu_irq(ipi_irq_base + i, 0);
718}
719
720void __init set_smp_ipi_range(int ipi_base, int n)
721{
722 int i;
723
724 WARN_ON(n < MAX_IPI);
725 nr_ipi = min(n, MAX_IPI);
726
727 for (i = 0; i < nr_ipi; i++) {
728 int err;
729
730 err = request_percpu_irq(ipi_base + i, ipi_handler,
731 "IPI", &irq_stat);
732 WARN_ON(err);
733
734 ipi_desc[i] = irq_to_desc(ipi_base + i);
735 irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
736 }
737
738 ipi_irq_base = ipi_base;
739
740 /* Setup the boot CPU immediately */
741 ipi_setup(smp_processor_id());
742}
743
744void smp_send_reschedule(int cpu)
745{
746 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
747}
748
749void smp_send_stop(void)
750{
751 unsigned long timeout;
752 struct cpumask mask;
753
754 cpumask_copy(&mask, cpu_online_mask);
755 cpumask_clear_cpu(smp_processor_id(), &mask);
756 if (!cpumask_empty(&mask))
757 smp_cross_call(&mask, IPI_CPU_STOP);
758
759 /* Wait up to one second for other CPUs to stop */
760 timeout = USEC_PER_SEC;
761 while (num_online_cpus() > 1 && timeout--)
762 udelay(1);
763
764 if (num_online_cpus() > 1)
765 pr_warn("SMP: failed to stop secondary CPUs\n");
766}
767
768/* In case panic() and panic() called at the same time on CPU1 and CPU2,
769 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
770 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
771 * kdump fails. So split out the panic_smp_self_stop() and add
772 * set_cpu_online(smp_processor_id(), false).
773 */
774void panic_smp_self_stop(void)
775{
776 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
777 smp_processor_id());
778 set_cpu_online(smp_processor_id(), false);
779 while (1)
780 cpu_relax();
781}
782
783/*
784 * not supported here
785 */
786int setup_profiling_timer(unsigned int multiplier)
787{
788 return -EINVAL;
789}
790
791#ifdef CONFIG_CPU_FREQ
792
793static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
794static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
795static unsigned long global_l_p_j_ref;
796static unsigned long global_l_p_j_ref_freq;
797
798static int cpufreq_callback(struct notifier_block *nb,
799 unsigned long val, void *data)
800{
801 struct cpufreq_freqs *freq = data;
802 struct cpumask *cpus = freq->policy->cpus;
803 int cpu, first = cpumask_first(cpus);
804 unsigned int lpj;
805
806 if (freq->flags & CPUFREQ_CONST_LOOPS)
807 return NOTIFY_OK;
808
809 if (!per_cpu(l_p_j_ref, first)) {
810 for_each_cpu(cpu, cpus) {
811 per_cpu(l_p_j_ref, cpu) =
812 per_cpu(cpu_data, cpu).loops_per_jiffy;
813 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
814 }
815
816 if (!global_l_p_j_ref) {
817 global_l_p_j_ref = loops_per_jiffy;
818 global_l_p_j_ref_freq = freq->old;
819 }
820 }
821
822 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
823 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
824 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
825 global_l_p_j_ref_freq,
826 freq->new);
827
828 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first),
829 per_cpu(l_p_j_ref_freq, first), freq->new);
830 for_each_cpu(cpu, cpus)
831 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj;
832 }
833 return NOTIFY_OK;
834}
835
836static struct notifier_block cpufreq_notifier = {
837 .notifier_call = cpufreq_callback,
838};
839
840static int __init register_cpufreq_notifier(void)
841{
842 return cpufreq_register_notifier(&cpufreq_notifier,
843 CPUFREQ_TRANSITION_NOTIFIER);
844}
845core_initcall(register_cpufreq_notifier);
846
847#endif
848
849static void raise_nmi(cpumask_t *mask)
850{
851 __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask);
852}
853
854void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
855{
856 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
857}