Merge tag 'virt' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
[linux-3.10.git] / arch / arm / kernel / smp.c
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/virt.h>
47 #include <asm/mach/arch.h>
48
49 /*
50  * as from 2.5, kernels no longer have an init_tasks structure
51  * so we need some other way of telling a new secondary core
52  * where to place its SVC stack
53  */
54 struct secondary_data secondary_data;
55
56 /*
57  * control for which core is the next to come out of the secondary
58  * boot "holding pen"
59  */
60 volatile int __cpuinitdata pen_release = -1;
61
62 enum ipi_msg_type {
63         IPI_WAKEUP,
64         IPI_TIMER,
65         IPI_RESCHEDULE,
66         IPI_CALL_FUNC,
67         IPI_CALL_FUNC_SINGLE,
68         IPI_CPU_STOP,
69 };
70
71 static DECLARE_COMPLETION(cpu_running);
72
73 static struct smp_operations smp_ops;
74
75 void __init smp_set_ops(struct smp_operations *ops)
76 {
77         if (ops)
78                 smp_ops = *ops;
79 };
80
81 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
82 {
83         int ret;
84
85         /*
86          * We need to tell the secondary core where to find
87          * its stack and the page tables.
88          */
89         secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
90         secondary_data.pgdir = virt_to_phys(idmap_pgd);
91         secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
92         __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
93         outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
94
95         /*
96          * Now bring the CPU into our world.
97          */
98         ret = boot_secondary(cpu, idle);
99         if (ret == 0) {
100                 /*
101                  * CPU was successfully started, wait for it
102                  * to come online or time out.
103                  */
104                 wait_for_completion_timeout(&cpu_running,
105                                                  msecs_to_jiffies(1000));
106
107                 if (!cpu_online(cpu)) {
108                         pr_crit("CPU%u: failed to come online\n", cpu);
109                         ret = -EIO;
110                 }
111         } else {
112                 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
113         }
114
115         secondary_data.stack = NULL;
116         secondary_data.pgdir = 0;
117
118         return ret;
119 }
120
121 /* platform specific SMP operations */
122 void __init smp_init_cpus(void)
123 {
124         if (smp_ops.smp_init_cpus)
125                 smp_ops.smp_init_cpus();
126 }
127
128 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
129 {
130         if (smp_ops.smp_boot_secondary)
131                 return smp_ops.smp_boot_secondary(cpu, idle);
132         return -ENOSYS;
133 }
134
135 #ifdef CONFIG_HOTPLUG_CPU
136 static void percpu_timer_stop(void);
137
138 static int platform_cpu_kill(unsigned int cpu)
139 {
140         if (smp_ops.cpu_kill)
141                 return smp_ops.cpu_kill(cpu);
142         return 1;
143 }
144
145 static int platform_cpu_disable(unsigned int cpu)
146 {
147         if (smp_ops.cpu_disable)
148                 return smp_ops.cpu_disable(cpu);
149
150         /*
151          * By default, allow disabling all CPUs except the first one,
152          * since this is special on a lot of platforms, e.g. because
153          * of clock tick interrupts.
154          */
155         return cpu == 0 ? -EPERM : 0;
156 }
157 /*
158  * __cpu_disable runs on the processor to be shutdown.
159  */
160 int __cpuinit __cpu_disable(void)
161 {
162         unsigned int cpu = smp_processor_id();
163         int ret;
164
165         ret = platform_cpu_disable(cpu);
166         if (ret)
167                 return ret;
168
169         /*
170          * Take this CPU offline.  Once we clear this, we can't return,
171          * and we must not schedule until we're ready to give up the cpu.
172          */
173         set_cpu_online(cpu, false);
174
175         /*
176          * OK - migrate IRQs away from this CPU
177          */
178         migrate_irqs();
179
180         /*
181          * Stop the local timer for this CPU.
182          */
183         percpu_timer_stop();
184
185         /*
186          * Flush user cache and TLB mappings, and then remove this CPU
187          * from the vm mask set of all processes.
188          *
189          * Caches are flushed to the Level of Unification Inner Shareable
190          * to write-back dirty lines to unified caches shared by all CPUs.
191          */
192         flush_cache_louis();
193         local_flush_tlb_all();
194
195         clear_tasks_mm_cpumask(cpu);
196
197         return 0;
198 }
199
200 static DECLARE_COMPLETION(cpu_died);
201
202 /*
203  * called on the thread which is asking for a CPU to be shutdown -
204  * waits until shutdown has completed, or it is timed out.
205  */
206 void __cpuinit __cpu_die(unsigned int cpu)
207 {
208         if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
209                 pr_err("CPU%u: cpu didn't die\n", cpu);
210                 return;
211         }
212         printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
213
214         if (!platform_cpu_kill(cpu))
215                 printk("CPU%u: unable to kill\n", cpu);
216 }
217
218 /*
219  * Called from the idle thread for the CPU which has been shutdown.
220  *
221  * Note that we disable IRQs here, but do not re-enable them
222  * before returning to the caller. This is also the behaviour
223  * of the other hotplug-cpu capable cores, so presumably coming
224  * out of idle fixes this.
225  */
226 void __ref cpu_die(void)
227 {
228         unsigned int cpu = smp_processor_id();
229
230         idle_task_exit();
231
232         local_irq_disable();
233         mb();
234
235         /* Tell __cpu_die() that this CPU is now safe to dispose of */
236         RCU_NONIDLE(complete(&cpu_died));
237
238         /*
239          * actual CPU shutdown procedure is at least platform (if not
240          * CPU) specific.
241          */
242         if (smp_ops.cpu_die)
243                 smp_ops.cpu_die(cpu);
244
245         /*
246          * Do not return to the idle loop - jump back to the secondary
247          * cpu initialisation.  There's some initialisation which needs
248          * to be repeated to undo the effects of taking the CPU offline.
249          */
250         __asm__("mov    sp, %0\n"
251         "       mov     fp, #0\n"
252         "       b       secondary_start_kernel"
253                 :
254                 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
255 }
256 #endif /* CONFIG_HOTPLUG_CPU */
257
258 /*
259  * Called by both boot and secondaries to move global data into
260  * per-processor storage.
261  */
262 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
263 {
264         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
265
266         cpu_info->loops_per_jiffy = loops_per_jiffy;
267         cpu_info->cpuid = read_cpuid_id();
268
269         store_cpu_topology(cpuid);
270 }
271
272 static void percpu_timer_setup(void);
273
274 /*
275  * This is the secondary CPU boot entry.  We're using this CPUs
276  * idle thread stack, but a set of temporary page tables.
277  */
278 asmlinkage void __cpuinit secondary_start_kernel(void)
279 {
280         struct mm_struct *mm = &init_mm;
281         unsigned int cpu;
282
283         /*
284          * The identity mapping is uncached (strongly ordered), so
285          * switch away from it before attempting any exclusive accesses.
286          */
287         cpu_switch_mm(mm->pgd, mm);
288         enter_lazy_tlb(mm, current);
289         local_flush_tlb_all();
290
291         /*
292          * All kernel threads share the same mm context; grab a
293          * reference and switch to it.
294          */
295         cpu = smp_processor_id();
296         atomic_inc(&mm->mm_count);
297         current->active_mm = mm;
298         cpumask_set_cpu(cpu, mm_cpumask(mm));
299
300         cpu_init();
301
302         printk("CPU%u: Booted secondary processor\n", cpu);
303
304         preempt_disable();
305         trace_hardirqs_off();
306
307         /*
308          * Give the platform a chance to do its own initialisation.
309          */
310         if (smp_ops.smp_secondary_init)
311                 smp_ops.smp_secondary_init(cpu);
312
313         notify_cpu_starting(cpu);
314
315         calibrate_delay();
316
317         smp_store_cpu_info(cpu);
318
319         /*
320          * OK, now it's safe to let the boot CPU continue.  Wait for
321          * the CPU migration code to notice that the CPU is online
322          * before we continue - which happens after __cpu_up returns.
323          */
324         set_cpu_online(cpu, true);
325         complete(&cpu_running);
326
327         /*
328          * Setup the percpu timer for this CPU.
329          */
330         percpu_timer_setup();
331
332         local_irq_enable();
333         local_fiq_enable();
334
335         /*
336          * OK, it's off to the idle thread for us
337          */
338         cpu_idle();
339 }
340
341 void __init smp_cpus_done(unsigned int max_cpus)
342 {
343         int cpu;
344         unsigned long bogosum = 0;
345
346         for_each_online_cpu(cpu)
347                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
348
349         printk(KERN_INFO "SMP: Total of %d processors activated "
350                "(%lu.%02lu BogoMIPS).\n",
351                num_online_cpus(),
352                bogosum / (500000/HZ),
353                (bogosum / (5000/HZ)) % 100);
354
355         hyp_mode_check();
356 }
357
358 void __init smp_prepare_boot_cpu(void)
359 {
360         set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
361 }
362
363 void __init smp_prepare_cpus(unsigned int max_cpus)
364 {
365         unsigned int ncores = num_possible_cpus();
366
367         init_cpu_topology();
368
369         smp_store_cpu_info(smp_processor_id());
370
371         /*
372          * are we trying to boot more cores than exist?
373          */
374         if (max_cpus > ncores)
375                 max_cpus = ncores;
376         if (ncores > 1 && max_cpus) {
377                 /*
378                  * Enable the local timer or broadcast device for the
379                  * boot CPU, but only if we have more than one CPU.
380                  */
381                 percpu_timer_setup();
382
383                 /*
384                  * Initialise the present map, which describes the set of CPUs
385                  * actually populated at the present time. A platform should
386                  * re-initialize the map in the platforms smp_prepare_cpus()
387                  * if present != possible (e.g. physical hotplug).
388                  */
389                 init_cpu_present(cpu_possible_mask);
390
391                 /*
392                  * Initialise the SCU if there are more than one CPU
393                  * and let them know where to start.
394                  */
395                 if (smp_ops.smp_prepare_cpus)
396                         smp_ops.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         if (!smp_cross_call)
405                 smp_cross_call = fn;
406 }
407
408 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
409 {
410         smp_cross_call(mask, IPI_CALL_FUNC);
411 }
412
413 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
414 {
415         smp_cross_call(mask, IPI_WAKEUP);
416 }
417
418 void arch_send_call_function_single_ipi(int cpu)
419 {
420         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
421 }
422
423 static const char *ipi_types[NR_IPI] = {
424 #define S(x,s)  [x] = s
425         S(IPI_WAKEUP, "CPU wakeup interrupts"),
426         S(IPI_TIMER, "Timer broadcast interrupts"),
427         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
428         S(IPI_CALL_FUNC, "Function call interrupts"),
429         S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
430         S(IPI_CPU_STOP, "CPU stop interrupts"),
431 };
432
433 void show_ipi_list(struct seq_file *p, int prec)
434 {
435         unsigned int cpu, i;
436
437         for (i = 0; i < NR_IPI; i++) {
438                 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
439
440                 for_each_online_cpu(cpu)
441                         seq_printf(p, "%10u ",
442                                    __get_irq_stat(cpu, ipi_irqs[i]));
443
444                 seq_printf(p, " %s\n", ipi_types[i]);
445         }
446 }
447
448 u64 smp_irq_stat_cpu(unsigned int cpu)
449 {
450         u64 sum = 0;
451         int i;
452
453         for (i = 0; i < NR_IPI; i++)
454                 sum += __get_irq_stat(cpu, ipi_irqs[i]);
455
456         return sum;
457 }
458
459 /*
460  * Timer (local or broadcast) support
461  */
462 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
463
464 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
465 void tick_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
514         if (!lt_ops || lt_ops->setup(evt))
515                 broadcast_timer_setup(evt);
516 }
517
518 #ifdef CONFIG_HOTPLUG_CPU
519 /*
520  * The generic clock events code purposely does not stop the local timer
521  * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
522  * manually here.
523  */
524 static void percpu_timer_stop(void)
525 {
526         unsigned int cpu = smp_processor_id();
527         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
528
529         if (lt_ops)
530                 lt_ops->stop(evt);
531 }
532 #endif
533
534 static DEFINE_RAW_SPINLOCK(stop_lock);
535
536 /*
537  * ipi_cpu_stop - handle IPI from smp_send_stop()
538  */
539 static void ipi_cpu_stop(unsigned int cpu)
540 {
541         if (system_state == SYSTEM_BOOTING ||
542             system_state == SYSTEM_RUNNING) {
543                 raw_spin_lock(&stop_lock);
544                 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
545                 dump_stack();
546                 raw_spin_unlock(&stop_lock);
547         }
548
549         set_cpu_online(cpu, false);
550
551         local_fiq_disable();
552         local_irq_disable();
553
554         while (1)
555                 cpu_relax();
556 }
557
558 /*
559  * Main handler for inter-processor interrupts
560  */
561 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
562 {
563         handle_IPI(ipinr, regs);
564 }
565
566 void handle_IPI(int ipinr, struct pt_regs *regs)
567 {
568         unsigned int cpu = smp_processor_id();
569         struct pt_regs *old_regs = set_irq_regs(regs);
570
571         if (ipinr < NR_IPI)
572                 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
573
574         switch (ipinr) {
575         case IPI_WAKEUP:
576                 break;
577
578 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
579         case IPI_TIMER:
580                 irq_enter();
581                 tick_receive_broadcast();
582                 irq_exit();
583                 break;
584 #endif
585
586         case IPI_RESCHEDULE:
587                 scheduler_ipi();
588                 break;
589
590         case IPI_CALL_FUNC:
591                 irq_enter();
592                 generic_smp_call_function_interrupt();
593                 irq_exit();
594                 break;
595
596         case IPI_CALL_FUNC_SINGLE:
597                 irq_enter();
598                 generic_smp_call_function_single_interrupt();
599                 irq_exit();
600                 break;
601
602         case IPI_CPU_STOP:
603                 irq_enter();
604                 ipi_cpu_stop(cpu);
605                 irq_exit();
606                 break;
607
608         default:
609                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
610                        cpu, ipinr);
611                 break;
612         }
613         set_irq_regs(old_regs);
614 }
615
616 void smp_send_reschedule(int cpu)
617 {
618         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
619 }
620
621 #ifdef CONFIG_HOTPLUG_CPU
622 static void smp_kill_cpus(cpumask_t *mask)
623 {
624         unsigned int cpu;
625         for_each_cpu(cpu, mask)
626                 platform_cpu_kill(cpu);
627 }
628 #else
629 static void smp_kill_cpus(cpumask_t *mask) { }
630 #endif
631
632 void smp_send_stop(void)
633 {
634         unsigned long timeout;
635         struct cpumask mask;
636
637         cpumask_copy(&mask, cpu_online_mask);
638         cpumask_clear_cpu(smp_processor_id(), &mask);
639         if (!cpumask_empty(&mask))
640                 smp_cross_call(&mask, IPI_CPU_STOP);
641
642         /* Wait up to one second for other CPUs to stop */
643         timeout = USEC_PER_SEC;
644         while (num_online_cpus() > 1 && timeout--)
645                 udelay(1);
646
647         if (num_online_cpus() > 1)
648                 pr_warning("SMP: failed to stop secondary CPUs\n");
649
650         smp_kill_cpus(&mask);
651 }
652
653 /*
654  * not supported here
655  */
656 int setup_profiling_timer(unsigned int multiplier)
657 {
658         return -EINVAL;
659 }
660
661 #ifdef CONFIG_CPU_FREQ
662
663 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
664 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
665 static unsigned long global_l_p_j_ref;
666 static unsigned long global_l_p_j_ref_freq;
667
668 static int cpufreq_callback(struct notifier_block *nb,
669                                         unsigned long val, void *data)
670 {
671         struct cpufreq_freqs *freq = data;
672         int cpu = freq->cpu;
673
674         if (freq->flags & CPUFREQ_CONST_LOOPS)
675                 return NOTIFY_OK;
676
677         if (!per_cpu(l_p_j_ref, cpu)) {
678                 per_cpu(l_p_j_ref, cpu) =
679                         per_cpu(cpu_data, cpu).loops_per_jiffy;
680                 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
681                 if (!global_l_p_j_ref) {
682                         global_l_p_j_ref = loops_per_jiffy;
683                         global_l_p_j_ref_freq = freq->old;
684                 }
685         }
686
687         if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
688             (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
689             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
690                 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
691                                                 global_l_p_j_ref_freq,
692                                                 freq->new);
693                 per_cpu(cpu_data, cpu).loops_per_jiffy =
694                         cpufreq_scale(per_cpu(l_p_j_ref, cpu),
695                                         per_cpu(l_p_j_ref_freq, cpu),
696                                         freq->new);
697         }
698         return NOTIFY_OK;
699 }
700
701 static struct notifier_block cpufreq_notifier = {
702         .notifier_call  = cpufreq_callback,
703 };
704
705 static int __init register_cpufreq_notifier(void)
706 {
707         return cpufreq_register_notifier(&cpufreq_notifier,
708                                                 CPUFREQ_TRANSITION_NOTIFIER);
709 }
710 core_initcall(register_cpufreq_notifier);
711
712 #endif