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