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