Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[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         local_flush_bp_all();
289         enter_lazy_tlb(mm, current);
290         local_flush_tlb_all();
291
292         /*
293          * All kernel threads share the same mm context; grab a
294          * reference and switch to it.
295          */
296         cpu = smp_processor_id();
297         atomic_inc(&mm->mm_count);
298         current->active_mm = mm;
299         cpumask_set_cpu(cpu, mm_cpumask(mm));
300
301         cpu_init();
302
303         printk("CPU%u: Booted secondary processor\n", cpu);
304
305         preempt_disable();
306         trace_hardirqs_off();
307
308         /*
309          * Give the platform a chance to do its own initialisation.
310          */
311         if (smp_ops.smp_secondary_init)
312                 smp_ops.smp_secondary_init(cpu);
313
314         notify_cpu_starting(cpu);
315
316         calibrate_delay();
317
318         smp_store_cpu_info(cpu);
319
320         /*
321          * OK, now it's safe to let the boot CPU continue.  Wait for
322          * the CPU migration code to notice that the CPU is online
323          * before we continue - which happens after __cpu_up returns.
324          */
325         set_cpu_online(cpu, true);
326         complete(&cpu_running);
327
328         /*
329          * Setup the percpu timer for this CPU.
330          */
331         percpu_timer_setup();
332
333         local_irq_enable();
334         local_fiq_enable();
335
336         /*
337          * OK, it's off to the idle thread for us
338          */
339         cpu_startup_entry(CPUHP_ONLINE);
340 }
341
342 void __init smp_cpus_done(unsigned int max_cpus)
343 {
344         int cpu;
345         unsigned long bogosum = 0;
346
347         for_each_online_cpu(cpu)
348                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
349
350         printk(KERN_INFO "SMP: Total of %d processors activated "
351                "(%lu.%02lu BogoMIPS).\n",
352                num_online_cpus(),
353                bogosum / (500000/HZ),
354                (bogosum / (5000/HZ)) % 100);
355
356         hyp_mode_check();
357 }
358
359 void __init smp_prepare_boot_cpu(void)
360 {
361         set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
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 the platforms smp_prepare_cpus()
388                  * if 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                 if (smp_ops.smp_prepare_cpus)
397                         smp_ops.smp_prepare_cpus(max_cpus);
398         }
399 }
400
401 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
402
403 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
404 {
405         if (!smp_cross_call)
406                 smp_cross_call = fn;
407 }
408
409 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
410 {
411         smp_cross_call(mask, IPI_CALL_FUNC);
412 }
413
414 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
415 {
416         smp_cross_call(mask, IPI_WAKEUP);
417 }
418
419 void arch_send_call_function_single_ipi(int cpu)
420 {
421         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
422 }
423
424 static const char *ipi_types[NR_IPI] = {
425 #define S(x,s)  [x] = s
426         S(IPI_WAKEUP, "CPU wakeup interrupts"),
427         S(IPI_TIMER, "Timer broadcast interrupts"),
428         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
429         S(IPI_CALL_FUNC, "Function call interrupts"),
430         S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
431         S(IPI_CPU_STOP, "CPU stop interrupts"),
432 };
433
434 void show_ipi_list(struct seq_file *p, int prec)
435 {
436         unsigned int cpu, i;
437
438         for (i = 0; i < NR_IPI; i++) {
439                 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
440
441                 for_each_online_cpu(cpu)
442                         seq_printf(p, "%10u ",
443                                    __get_irq_stat(cpu, ipi_irqs[i]));
444
445                 seq_printf(p, " %s\n", ipi_types[i]);
446         }
447 }
448
449 u64 smp_irq_stat_cpu(unsigned int cpu)
450 {
451         u64 sum = 0;
452         int i;
453
454         for (i = 0; i < NR_IPI; i++)
455                 sum += __get_irq_stat(cpu, ipi_irqs[i]);
456
457         return sum;
458 }
459
460 /*
461  * Timer (local or broadcast) support
462  */
463 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
464
465 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
466 void tick_broadcast(const struct cpumask *mask)
467 {
468         smp_cross_call(mask, IPI_TIMER);
469 }
470 #endif
471
472 static void broadcast_timer_set_mode(enum clock_event_mode mode,
473         struct clock_event_device *evt)
474 {
475 }
476
477 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
478 {
479         evt->name       = "dummy_timer";
480         evt->features   = CLOCK_EVT_FEAT_ONESHOT |
481                           CLOCK_EVT_FEAT_PERIODIC |
482                           CLOCK_EVT_FEAT_DUMMY;
483         evt->rating     = 100;
484         evt->mult       = 1;
485         evt->set_mode   = broadcast_timer_set_mode;
486
487         clockevents_register_device(evt);
488 }
489
490 static struct local_timer_ops *lt_ops;
491
492 #ifdef CONFIG_LOCAL_TIMERS
493 int local_timer_register(struct local_timer_ops *ops)
494 {
495         if (!is_smp() || !setup_max_cpus)
496                 return -ENXIO;
497
498         if (lt_ops)
499                 return -EBUSY;
500
501         lt_ops = ops;
502         return 0;
503 }
504 #endif
505
506 static void __cpuinit percpu_timer_setup(void)
507 {
508         unsigned int cpu = smp_processor_id();
509         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
510
511         evt->cpumask = cpumask_of(cpu);
512
513         if (!lt_ops || lt_ops->setup(evt))
514                 broadcast_timer_setup(evt);
515 }
516
517 #ifdef CONFIG_HOTPLUG_CPU
518 /*
519  * The generic clock events code purposely does not stop the local timer
520  * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
521  * manually here.
522  */
523 static void percpu_timer_stop(void)
524 {
525         unsigned int cpu = smp_processor_id();
526         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
527
528         if (lt_ops)
529                 lt_ops->stop(evt);
530 }
531 #endif
532
533 static DEFINE_RAW_SPINLOCK(stop_lock);
534
535 /*
536  * ipi_cpu_stop - handle IPI from smp_send_stop()
537  */
538 static void ipi_cpu_stop(unsigned int cpu)
539 {
540         if (system_state == SYSTEM_BOOTING ||
541             system_state == SYSTEM_RUNNING) {
542                 raw_spin_lock(&stop_lock);
543                 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
544                 dump_stack();
545                 raw_spin_unlock(&stop_lock);
546         }
547
548         set_cpu_online(cpu, false);
549
550         local_fiq_disable();
551         local_irq_disable();
552
553         while (1)
554                 cpu_relax();
555 }
556
557 /*
558  * Main handler for inter-processor interrupts
559  */
560 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
561 {
562         handle_IPI(ipinr, regs);
563 }
564
565 void handle_IPI(int ipinr, struct pt_regs *regs)
566 {
567         unsigned int cpu = smp_processor_id();
568         struct pt_regs *old_regs = set_irq_regs(regs);
569
570         if (ipinr < NR_IPI)
571                 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
572
573         switch (ipinr) {
574         case IPI_WAKEUP:
575                 break;
576
577 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
578         case IPI_TIMER:
579                 irq_enter();
580                 tick_receive_broadcast();
581                 irq_exit();
582                 break;
583 #endif
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