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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/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
29 #include <linux/atomic.h>
30 #include <asm/smp.h>
31 #include <asm/cacheflush.h>
32 #include <asm/cpu.h>
33 #include <asm/cputype.h>
34 #include <asm/exception.h>
35 #include <asm/idmap.h>
36 #include <asm/topology.h>
37 #include <asm/mmu_context.h>
38 #include <asm/pgtable.h>
39 #include <asm/pgalloc.h>
40 #include <asm/processor.h>
41 #include <asm/sections.h>
42 #include <asm/tlbflush.h>
43 #include <asm/ptrace.h>
44 #include <asm/localtimer.h>
45 #include <asm/smp_plat.h>
46 #include <asm/mach/arch.h>
47
48 /*
49  * as from 2.5, kernels no longer have an init_tasks structure
50  * so we need some other way of telling a new secondary core
51  * where to place its SVC stack
52  */
53 struct secondary_data secondary_data;
54
55 /*
56  * control for which core is the next to come out of the secondary
57  * boot "holding pen"
58  */
59 volatile int __cpuinitdata pen_release = -1;
60
61 enum ipi_msg_type {
62         IPI_WAKEUP,
63         IPI_TIMER,
64         IPI_RESCHEDULE,
65         IPI_CALL_FUNC,
66         IPI_CALL_FUNC_SINGLE,
67         IPI_CPU_STOP,
68 };
69
70 static DECLARE_COMPLETION(cpu_running);
71
72 static struct smp_operations smp_ops;
73
74 void __init smp_set_ops(struct smp_operations *ops)
75 {
76         if (ops)
77                 smp_ops = *ops;
78 };
79
80 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
81 {
82         int ret;
83
84         /*
85          * We need to tell the secondary core where to find
86          * its stack and the page tables.
87          */
88         secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
89         secondary_data.pgdir = virt_to_phys(idmap_pgd);
90         secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
91         __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
92         outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
93
94         /*
95          * Now bring the CPU into our world.
96          */
97         ret = boot_secondary(cpu, idle);
98         if (ret == 0) {
99                 /*
100                  * CPU was successfully started, wait for it
101                  * to come online or time out.
102                  */
103                 wait_for_completion_timeout(&cpu_running,
104                                                  msecs_to_jiffies(1000));
105
106                 if (!cpu_online(cpu)) {
107                         pr_crit("CPU%u: failed to come online\n", cpu);
108                         ret = -EIO;
109                 }
110         } else {
111                 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
112         }
113
114         secondary_data.stack = NULL;
115         secondary_data.pgdir = 0;
116
117         return ret;
118 }
119
120 /* platform specific SMP operations */
121 void __init smp_init_cpus(void)
122 {
123         if (smp_ops.smp_init_cpus)
124                 smp_ops.smp_init_cpus();
125 }
126
127 static void __init platform_smp_prepare_cpus(unsigned int max_cpus)
128 {
129         if (smp_ops.smp_prepare_cpus)
130                 smp_ops.smp_prepare_cpus(max_cpus);
131 }
132
133 static void __cpuinit platform_secondary_init(unsigned int cpu)
134 {
135         if (smp_ops.smp_secondary_init)
136                 smp_ops.smp_secondary_init(cpu);
137 }
138
139 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
140 {
141         if (smp_ops.smp_boot_secondary)
142                 return smp_ops.smp_boot_secondary(cpu, idle);
143         return -ENOSYS;
144 }
145
146 #ifdef CONFIG_HOTPLUG_CPU
147 static void percpu_timer_stop(void);
148
149 static int platform_cpu_kill(unsigned int cpu)
150 {
151         if (smp_ops.cpu_kill)
152                 return smp_ops.cpu_kill(cpu);
153         return 1;
154 }
155
156 static void platform_cpu_die(unsigned int cpu)
157 {
158         if (smp_ops.cpu_die)
159                 smp_ops.cpu_die(cpu);
160 }
161
162 static int platform_cpu_disable(unsigned int cpu)
163 {
164         if (smp_ops.cpu_disable)
165                 return smp_ops.cpu_disable(cpu);
166
167         /*
168          * By default, allow disabling all CPUs except the first one,
169          * since this is special on a lot of platforms, e.g. because
170          * of clock tick interrupts.
171          */
172         return cpu == 0 ? -EPERM : 0;
173 }
174 /*
175  * __cpu_disable runs on the processor to be shutdown.
176  */
177 int __cpuinit __cpu_disable(void)
178 {
179         unsigned int cpu = smp_processor_id();
180         int ret;
181
182         ret = platform_cpu_disable(cpu);
183         if (ret)
184                 return ret;
185
186         /*
187          * Take this CPU offline.  Once we clear this, we can't return,
188          * and we must not schedule until we're ready to give up the cpu.
189          */
190         set_cpu_online(cpu, false);
191
192         /*
193          * OK - migrate IRQs away from this CPU
194          */
195         migrate_irqs();
196
197         /*
198          * Stop the local timer for this CPU.
199          */
200         percpu_timer_stop();
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         flush_cache_all();
207         local_flush_tlb_all();
208
209         clear_tasks_mm_cpumask(cpu);
210
211         return 0;
212 }
213
214 static DECLARE_COMPLETION(cpu_died);
215
216 /*
217  * called on the thread which is asking for a CPU to be shutdown -
218  * waits until shutdown has completed, or it is timed out.
219  */
220 void __cpuinit __cpu_die(unsigned int cpu)
221 {
222         if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
223                 pr_err("CPU%u: cpu didn't die\n", cpu);
224                 return;
225         }
226         printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
227
228         if (!platform_cpu_kill(cpu))
229                 printk("CPU%u: unable to kill\n", cpu);
230 }
231
232 /*
233  * Called from the idle thread for the CPU which has been shutdown.
234  *
235  * Note that we disable IRQs here, but do not re-enable them
236  * before returning to the caller. This is also the behaviour
237  * of the other hotplug-cpu capable cores, so presumably coming
238  * out of idle fixes this.
239  */
240 void __ref cpu_die(void)
241 {
242         unsigned int cpu = smp_processor_id();
243
244         idle_task_exit();
245
246         local_irq_disable();
247         mb();
248
249         /* Tell __cpu_die() that this CPU is now safe to dispose of */
250         RCU_NONIDLE(complete(&cpu_died));
251
252         /*
253          * actual CPU shutdown procedure is at least platform (if not
254          * CPU) specific.
255          */
256         platform_cpu_die(cpu);
257
258         /*
259          * Do not return to the idle loop - jump back to the secondary
260          * cpu initialisation.  There's some initialisation which needs
261          * to be repeated to undo the effects of taking the CPU offline.
262          */
263         __asm__("mov    sp, %0\n"
264         "       mov     fp, #0\n"
265         "       b       secondary_start_kernel"
266                 :
267                 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
268 }
269 #endif /* CONFIG_HOTPLUG_CPU */
270
271 /*
272  * Called by both boot and secondaries to move global data into
273  * per-processor storage.
274  */
275 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
276 {
277         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
278
279         cpu_info->loops_per_jiffy = loops_per_jiffy;
280
281         store_cpu_topology(cpuid);
282 }
283
284 static void percpu_timer_setup(void);
285
286 /*
287  * This is the secondary CPU boot entry.  We're using this CPUs
288  * idle thread stack, but a set of temporary page tables.
289  */
290 asmlinkage void __cpuinit secondary_start_kernel(void)
291 {
292         struct mm_struct *mm = &init_mm;
293         unsigned int cpu = smp_processor_id();
294
295         /*
296          * All kernel threads share the same mm context; grab a
297          * reference and switch to it.
298          */
299         atomic_inc(&mm->mm_count);
300         current->active_mm = mm;
301         cpumask_set_cpu(cpu, mm_cpumask(mm));
302         cpu_switch_mm(mm->pgd, mm);
303         enter_lazy_tlb(mm, current);
304         local_flush_tlb_all();
305
306         printk("CPU%u: Booted secondary processor\n", cpu);
307
308         cpu_init();
309         preempt_disable();
310         trace_hardirqs_off();
311
312         /*
313          * Give the platform a chance to do its own initialisation.
314          */
315         platform_secondary_init(cpu);
316
317         notify_cpu_starting(cpu);
318
319         calibrate_delay();
320
321         smp_store_cpu_info(cpu);
322
323         /*
324          * OK, now it's safe to let the boot CPU continue.  Wait for
325          * the CPU migration code to notice that the CPU is online
326          * before we continue - which happens after __cpu_up returns.
327          */
328         set_cpu_online(cpu, true);
329         complete(&cpu_running);
330
331         /*
332          * Setup the percpu timer for this CPU.
333          */
334         percpu_timer_setup();
335
336         local_irq_enable();
337         local_fiq_enable();
338
339         /*
340          * OK, it's off to the idle thread for us
341          */
342         cpu_idle();
343 }
344
345 void __init smp_cpus_done(unsigned int max_cpus)
346 {
347         int cpu;
348         unsigned long bogosum = 0;
349
350         for_each_online_cpu(cpu)
351                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
352
353         printk(KERN_INFO "SMP: Total of %d processors activated "
354                "(%lu.%02lu BogoMIPS).\n",
355                num_online_cpus(),
356                bogosum / (500000/HZ),
357                (bogosum / (5000/HZ)) % 100);
358 }
359
360 void __init smp_prepare_boot_cpu(void)
361 {
362 }
363
364 void __init smp_prepare_cpus(unsigned int max_cpus)
365 {
366         unsigned int ncores = num_possible_cpus();
367
368         init_cpu_topology();
369
370         smp_store_cpu_info(smp_processor_id());
371
372         /*
373          * are we trying to boot more cores than exist?
374          */
375         if (max_cpus > ncores)
376                 max_cpus = ncores;
377         if (ncores > 1 && max_cpus) {
378                 /*
379                  * Enable the local timer or broadcast device for the
380                  * boot CPU, but only if we have more than one CPU.
381                  */
382                 percpu_timer_setup();
383
384                 /*
385                  * Initialise the present map, which describes the set of CPUs
386                  * actually populated at the present time. A platform should
387                  * re-initialize the map in platform_smp_prepare_cpus() if
388                  * present != possible (e.g. physical hotplug).
389                  */
390                 init_cpu_present(cpu_possible_mask);
391
392                 /*
393                  * Initialise the SCU if there are more than one CPU
394                  * and let them know where to start.
395                  */
396                 platform_smp_prepare_cpus(max_cpus);
397         }
398 }
399
400 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
401
402 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
403 {
404         smp_cross_call = fn;
405 }
406
407 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
408 {
409         smp_cross_call(mask, IPI_CALL_FUNC);
410 }
411
412 void arch_send_call_function_single_ipi(int cpu)
413 {
414         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
415 }
416
417 static const char *ipi_types[NR_IPI] = {
418 #define S(x,s)  [x] = s
419         S(IPI_WAKEUP, "CPU wakeup interrupts"),
420         S(IPI_TIMER, "Timer broadcast interrupts"),
421         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
422         S(IPI_CALL_FUNC, "Function call interrupts"),
423         S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
424         S(IPI_CPU_STOP, "CPU stop interrupts"),
425 };
426
427 void show_ipi_list(struct seq_file *p, int prec)
428 {
429         unsigned int cpu, i;
430
431         for (i = 0; i < NR_IPI; i++) {
432                 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
433
434                 for_each_present_cpu(cpu)
435                         seq_printf(p, "%10u ",
436                                    __get_irq_stat(cpu, ipi_irqs[i]));
437
438                 seq_printf(p, " %s\n", ipi_types[i]);
439         }
440 }
441
442 u64 smp_irq_stat_cpu(unsigned int cpu)
443 {
444         u64 sum = 0;
445         int i;
446
447         for (i = 0; i < NR_IPI; i++)
448                 sum += __get_irq_stat(cpu, ipi_irqs[i]);
449
450         return sum;
451 }
452
453 /*
454  * Timer (local or broadcast) support
455  */
456 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
457
458 static void ipi_timer(void)
459 {
460         struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
461         evt->event_handler(evt);
462 }
463
464 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
465 static void smp_timer_broadcast(const struct cpumask *mask)
466 {
467         smp_cross_call(mask, IPI_TIMER);
468 }
469 #else
470 #define smp_timer_broadcast     NULL
471 #endif
472
473 static void broadcast_timer_set_mode(enum clock_event_mode mode,
474         struct clock_event_device *evt)
475 {
476 }
477
478 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
479 {
480         evt->name       = "dummy_timer";
481         evt->features   = CLOCK_EVT_FEAT_ONESHOT |
482                           CLOCK_EVT_FEAT_PERIODIC |
483                           CLOCK_EVT_FEAT_DUMMY;
484         evt->rating     = 400;
485         evt->mult       = 1;
486         evt->set_mode   = broadcast_timer_set_mode;
487
488         clockevents_register_device(evt);
489 }
490
491 static struct local_timer_ops *lt_ops;
492
493 #ifdef CONFIG_LOCAL_TIMERS
494 int local_timer_register(struct local_timer_ops *ops)
495 {
496         if (!is_smp() || !setup_max_cpus)
497                 return -ENXIO;
498
499         if (lt_ops)
500                 return -EBUSY;
501
502         lt_ops = ops;
503         return 0;
504 }
505 #endif
506
507 static void __cpuinit percpu_timer_setup(void)
508 {
509         unsigned int cpu = smp_processor_id();
510         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
511
512         evt->cpumask = cpumask_of(cpu);
513         evt->broadcast = smp_timer_broadcast;
514
515         if (!lt_ops || lt_ops->setup(evt))
516                 broadcast_timer_setup(evt);
517 }
518
519 #ifdef CONFIG_HOTPLUG_CPU
520 /*
521  * The generic clock events code purposely does not stop the local timer
522  * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
523  * manually here.
524  */
525 static void percpu_timer_stop(void)
526 {
527         unsigned int cpu = smp_processor_id();
528         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
529
530         if (lt_ops)
531                 lt_ops->stop(evt);
532 }
533 #endif
534
535 static DEFINE_RAW_SPINLOCK(stop_lock);
536
537 /*
538  * ipi_cpu_stop - handle IPI from smp_send_stop()
539  */
540 static void ipi_cpu_stop(unsigned int cpu)
541 {
542         if (system_state == SYSTEM_BOOTING ||
543             system_state == SYSTEM_RUNNING) {
544                 raw_spin_lock(&stop_lock);
545                 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
546                 dump_stack();
547                 raw_spin_unlock(&stop_lock);
548         }
549
550         set_cpu_online(cpu, false);
551
552         local_fiq_disable();
553         local_irq_disable();
554
555         while (1)
556                 cpu_relax();
557 }
558
559 /*
560  * Main handler for inter-processor interrupts
561  */
562 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
563 {
564         handle_IPI(ipinr, regs);
565 }
566
567 void handle_IPI(int ipinr, struct pt_regs *regs)
568 {
569         unsigned int cpu = smp_processor_id();
570         struct pt_regs *old_regs = set_irq_regs(regs);
571
572         if (ipinr < NR_IPI)
573                 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
574
575         switch (ipinr) {
576         case IPI_WAKEUP:
577                 break;
578
579         case IPI_TIMER:
580                 irq_enter();
581                 ipi_timer();
582                 irq_exit();
583                 break;
584
585         case IPI_RESCHEDULE:
586                 scheduler_ipi();
587                 break;
588
589         case IPI_CALL_FUNC:
590                 irq_enter();
591                 generic_smp_call_function_interrupt();
592                 irq_exit();
593                 break;
594
595         case IPI_CALL_FUNC_SINGLE:
596                 irq_enter();
597                 generic_smp_call_function_single_interrupt();
598                 irq_exit();
599                 break;
600
601         case IPI_CPU_STOP:
602                 irq_enter();
603                 ipi_cpu_stop(cpu);
604                 irq_exit();
605                 break;
606
607         default:
608                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
609                        cpu, ipinr);
610                 break;
611         }
612         set_irq_regs(old_regs);
613 }
614
615 void smp_send_reschedule(int cpu)
616 {
617         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
618 }
619
620 #ifdef CONFIG_HOTPLUG_CPU
621 static void smp_kill_cpus(cpumask_t *mask)
622 {
623         unsigned int cpu;
624         for_each_cpu(cpu, mask)
625                 platform_cpu_kill(cpu);
626 }
627 #else
628 static void smp_kill_cpus(cpumask_t *mask) { }
629 #endif
630
631 void smp_send_stop(void)
632 {
633         unsigned long timeout;
634         struct cpumask mask;
635
636         cpumask_copy(&mask, cpu_online_mask);
637         cpumask_clear_cpu(smp_processor_id(), &mask);
638         if (!cpumask_empty(&mask))
639                 smp_cross_call(&mask, IPI_CPU_STOP);
640
641         /* Wait up to one second for other CPUs to stop */
642         timeout = USEC_PER_SEC;
643         while (num_online_cpus() > 1 && timeout--)
644                 udelay(1);
645
646         if (num_online_cpus() > 1)
647                 pr_warning("SMP: failed to stop secondary CPUs\n");
648
649         smp_kill_cpus(&mask);
650 }
651
652 /*
653  * not supported here
654  */
655 int setup_profiling_timer(unsigned int multiplier)
656 {
657         return -EINVAL;
658 }
659
660 #ifdef CONFIG_CPU_FREQ
661
662 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
663 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
664 static unsigned long global_l_p_j_ref;
665 static unsigned long global_l_p_j_ref_freq;
666
667 static int cpufreq_callback(struct notifier_block *nb,
668                                         unsigned long val, void *data)
669 {
670         struct cpufreq_freqs *freq = data;
671         int cpu = freq->cpu;
672
673         if (freq->flags & CPUFREQ_CONST_LOOPS)
674                 return NOTIFY_OK;
675
676         if (!per_cpu(l_p_j_ref, cpu)) {
677                 per_cpu(l_p_j_ref, cpu) =
678                         per_cpu(cpu_data, cpu).loops_per_jiffy;
679                 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
680                 if (!global_l_p_j_ref) {
681                         global_l_p_j_ref = loops_per_jiffy;
682                         global_l_p_j_ref_freq = freq->old;
683                 }
684         }
685
686         if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
687             (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
688             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
689                 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
690                                                 global_l_p_j_ref_freq,
691                                                 freq->new);
692                 per_cpu(cpu_data, cpu).loops_per_jiffy =
693                         cpufreq_scale(per_cpu(l_p_j_ref, cpu),
694                                         per_cpu(l_p_j_ref_freq, cpu),
695                                         freq->new);
696         }
697         return NOTIFY_OK;
698 }
699
700 static struct notifier_block cpufreq_notifier = {
701         .notifier_call  = cpufreq_callback,
702 };
703
704 static int __init register_cpufreq_notifier(void)
705 {
706         return cpufreq_register_notifier(&cpufreq_notifier,
707                                                 CPUFREQ_TRANSITION_NOTIFIER);
708 }
709 core_initcall(register_cpufreq_notifier);
710
711 #endif