Merge branches 'for-3.18/upstream-fixes' and 'for-3.19/upstream' into for-linus
[cascardo/linux.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 #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 #define CREATE_TRACE_POINTS
51 #include <trace/events/ipi.h>
52
53 /*
54  * as from 2.5, kernels no longer have an init_tasks structure
55  * so we need some other way of telling a new secondary core
56  * where to place its SVC stack
57  */
58 struct secondary_data secondary_data;
59
60 /*
61  * control for which core is the next to come out of the secondary
62  * boot "holding pen"
63  */
64 volatile int pen_release = -1;
65
66 enum ipi_msg_type {
67         IPI_WAKEUP,
68         IPI_TIMER,
69         IPI_RESCHEDULE,
70         IPI_CALL_FUNC,
71         IPI_CALL_FUNC_SINGLE,
72         IPI_CPU_STOP,
73         IPI_IRQ_WORK,
74         IPI_COMPLETION,
75 };
76
77 static DECLARE_COMPLETION(cpu_running);
78
79 static struct smp_operations smp_ops;
80
81 void __init smp_set_ops(struct smp_operations *ops)
82 {
83         if (ops)
84                 smp_ops = *ops;
85 };
86
87 static unsigned long get_arch_pgd(pgd_t *pgd)
88 {
89         phys_addr_t pgdir = virt_to_idmap(pgd);
90         BUG_ON(pgdir & ARCH_PGD_MASK);
91         return pgdir >> ARCH_PGD_SHIFT;
92 }
93
94 int __cpu_up(unsigned int cpu, struct task_struct *idle)
95 {
96         int ret;
97
98         if (!smp_ops.smp_boot_secondary)
99                 return -ENOSYS;
100
101         /*
102          * We need to tell the secondary core where to find
103          * its stack and the page tables.
104          */
105         secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
106 #ifdef CONFIG_ARM_MPU
107         secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr;
108 #endif
109
110 #ifdef CONFIG_MMU
111         secondary_data.pgdir = get_arch_pgd(idmap_pgd);
112         secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
113 #endif
114         sync_cache_w(&secondary_data);
115
116         /*
117          * Now bring the CPU into our world.
118          */
119         ret = smp_ops.smp_boot_secondary(cpu, idle);
120         if (ret == 0) {
121                 /*
122                  * CPU was successfully started, wait for it
123                  * to come online or time out.
124                  */
125                 wait_for_completion_timeout(&cpu_running,
126                                                  msecs_to_jiffies(1000));
127
128                 if (!cpu_online(cpu)) {
129                         pr_crit("CPU%u: failed to come online\n", cpu);
130                         ret = -EIO;
131                 }
132         } else {
133                 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
134         }
135
136
137         memset(&secondary_data, 0, sizeof(secondary_data));
138         return ret;
139 }
140
141 /* platform specific SMP operations */
142 void __init smp_init_cpus(void)
143 {
144         if (smp_ops.smp_init_cpus)
145                 smp_ops.smp_init_cpus();
146 }
147
148 int platform_can_cpu_hotplug(void)
149 {
150 #ifdef CONFIG_HOTPLUG_CPU
151         if (smp_ops.cpu_kill)
152                 return 1;
153 #endif
154
155         return 0;
156 }
157
158 #ifdef CONFIG_HOTPLUG_CPU
159 static int platform_cpu_kill(unsigned int cpu)
160 {
161         if (smp_ops.cpu_kill)
162                 return smp_ops.cpu_kill(cpu);
163         return 1;
164 }
165
166 static int platform_cpu_disable(unsigned int cpu)
167 {
168         if (smp_ops.cpu_disable)
169                 return smp_ops.cpu_disable(cpu);
170
171         /*
172          * By default, allow disabling all CPUs except the first one,
173          * since this is special on a lot of platforms, e.g. because
174          * of clock tick interrupts.
175          */
176         return cpu == 0 ? -EPERM : 0;
177 }
178 /*
179  * __cpu_disable runs on the processor to be shutdown.
180  */
181 int __cpu_disable(void)
182 {
183         unsigned int cpu = smp_processor_id();
184         int ret;
185
186         ret = platform_cpu_disable(cpu);
187         if (ret)
188                 return ret;
189
190         /*
191          * Take this CPU offline.  Once we clear this, we can't return,
192          * and we must not schedule until we're ready to give up the cpu.
193          */
194         set_cpu_online(cpu, false);
195
196         /*
197          * OK - migrate IRQs away from this CPU
198          */
199         migrate_irqs();
200
201         /*
202          * Flush user cache and TLB mappings, and then remove this CPU
203          * from the vm mask set of all processes.
204          *
205          * Caches are flushed to the Level of Unification Inner Shareable
206          * to write-back dirty lines to unified caches shared by all CPUs.
207          */
208         flush_cache_louis();
209         local_flush_tlb_all();
210
211         clear_tasks_mm_cpumask(cpu);
212
213         return 0;
214 }
215
216 static DECLARE_COMPLETION(cpu_died);
217
218 /*
219  * called on the thread which is asking for a CPU to be shutdown -
220  * waits until shutdown has completed, or it is timed out.
221  */
222 void __cpu_die(unsigned int cpu)
223 {
224         if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
225                 pr_err("CPU%u: cpu didn't die\n", cpu);
226                 return;
227         }
228         printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
229
230         /*
231          * platform_cpu_kill() is generally expected to do the powering off
232          * and/or cutting of clocks to the dying CPU.  Optionally, this may
233          * be done by the CPU which is dying in preference to supporting
234          * this call, but that means there is _no_ synchronisation between
235          * the requesting CPU and the dying CPU actually losing power.
236          */
237         if (!platform_cpu_kill(cpu))
238                 printk("CPU%u: unable to kill\n", cpu);
239 }
240
241 /*
242  * Called from the idle thread for the CPU which has been shutdown.
243  *
244  * Note that we disable IRQs here, but do not re-enable them
245  * before returning to the caller. This is also the behaviour
246  * of the other hotplug-cpu capable cores, so presumably coming
247  * out of idle fixes this.
248  */
249 void __ref cpu_die(void)
250 {
251         unsigned int cpu = smp_processor_id();
252
253         idle_task_exit();
254
255         local_irq_disable();
256
257         /*
258          * Flush the data out of the L1 cache for this CPU.  This must be
259          * before the completion to ensure that data is safely written out
260          * before platform_cpu_kill() gets called - which may disable
261          * *this* CPU and power down its cache.
262          */
263         flush_cache_louis();
264
265         /*
266          * Tell __cpu_die() that this CPU is now safe to dispose of.  Once
267          * this returns, power and/or clocks can be removed at any point
268          * from this CPU and its cache by platform_cpu_kill().
269          */
270         complete(&cpu_died);
271
272         /*
273          * Ensure that the cache lines associated with that completion are
274          * written out.  This covers the case where _this_ CPU is doing the
275          * powering down, to ensure that the completion is visible to the
276          * CPU waiting for this one.
277          */
278         flush_cache_louis();
279
280         /*
281          * The actual CPU shutdown procedure is at least platform (if not
282          * CPU) specific.  This may remove power, or it may simply spin.
283          *
284          * Platforms are generally expected *NOT* to return from this call,
285          * although there are some which do because they have no way to
286          * power down the CPU.  These platforms are the _only_ reason we
287          * have a return path which uses the fragment of assembly below.
288          *
289          * The return path should not be used for platforms which can
290          * power off the CPU.
291          */
292         if (smp_ops.cpu_die)
293                 smp_ops.cpu_die(cpu);
294
295         pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
296                 cpu);
297
298         /*
299          * Do not return to the idle loop - jump back to the secondary
300          * cpu initialisation.  There's some initialisation which needs
301          * to be repeated to undo the effects of taking the CPU offline.
302          */
303         __asm__("mov    sp, %0\n"
304         "       mov     fp, #0\n"
305         "       b       secondary_start_kernel"
306                 :
307                 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
308 }
309 #endif /* CONFIG_HOTPLUG_CPU */
310
311 /*
312  * Called by both boot and secondaries to move global data into
313  * per-processor storage.
314  */
315 static void smp_store_cpu_info(unsigned int cpuid)
316 {
317         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
318
319         cpu_info->loops_per_jiffy = loops_per_jiffy;
320         cpu_info->cpuid = read_cpuid_id();
321
322         store_cpu_topology(cpuid);
323 }
324
325 /*
326  * This is the secondary CPU boot entry.  We're using this CPUs
327  * idle thread stack, but a set of temporary page tables.
328  */
329 asmlinkage void secondary_start_kernel(void)
330 {
331         struct mm_struct *mm = &init_mm;
332         unsigned int cpu;
333
334         /*
335          * The identity mapping is uncached (strongly ordered), so
336          * switch away from it before attempting any exclusive accesses.
337          */
338         cpu_switch_mm(mm->pgd, mm);
339         local_flush_bp_all();
340         enter_lazy_tlb(mm, current);
341         local_flush_tlb_all();
342
343         /*
344          * All kernel threads share the same mm context; grab a
345          * reference and switch to it.
346          */
347         cpu = smp_processor_id();
348         atomic_inc(&mm->mm_count);
349         current->active_mm = mm;
350         cpumask_set_cpu(cpu, mm_cpumask(mm));
351
352         cpu_init();
353
354         printk("CPU%u: Booted secondary processor\n", cpu);
355
356         preempt_disable();
357         trace_hardirqs_off();
358
359         /*
360          * Give the platform a chance to do its own initialisation.
361          */
362         if (smp_ops.smp_secondary_init)
363                 smp_ops.smp_secondary_init(cpu);
364
365         notify_cpu_starting(cpu);
366
367         calibrate_delay();
368
369         smp_store_cpu_info(cpu);
370
371         /*
372          * OK, now it's safe to let the boot CPU continue.  Wait for
373          * the CPU migration code to notice that the CPU is online
374          * before we continue - which happens after __cpu_up returns.
375          */
376         set_cpu_online(cpu, true);
377         complete(&cpu_running);
378
379         local_irq_enable();
380         local_fiq_enable();
381
382         /*
383          * OK, it's off to the idle thread for us
384          */
385         cpu_startup_entry(CPUHP_ONLINE);
386 }
387
388 void __init smp_cpus_done(unsigned int max_cpus)
389 {
390         printk(KERN_INFO "SMP: Total of %d processors activated.\n",
391                num_online_cpus());
392
393         hyp_mode_check();
394 }
395
396 void __init smp_prepare_boot_cpu(void)
397 {
398         set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
399 }
400
401 void __init smp_prepare_cpus(unsigned int max_cpus)
402 {
403         unsigned int ncores = num_possible_cpus();
404
405         init_cpu_topology();
406
407         smp_store_cpu_info(smp_processor_id());
408
409         /*
410          * are we trying to boot more cores than exist?
411          */
412         if (max_cpus > ncores)
413                 max_cpus = ncores;
414         if (ncores > 1 && max_cpus) {
415                 /*
416                  * Initialise the present map, which describes the set of CPUs
417                  * actually populated at the present time. A platform should
418                  * re-initialize the map in the platforms smp_prepare_cpus()
419                  * if present != possible (e.g. physical hotplug).
420                  */
421                 init_cpu_present(cpu_possible_mask);
422
423                 /*
424                  * Initialise the SCU if there are more than one CPU
425                  * and let them know where to start.
426                  */
427                 if (smp_ops.smp_prepare_cpus)
428                         smp_ops.smp_prepare_cpus(max_cpus);
429         }
430 }
431
432 static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
433
434 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
435 {
436         if (!__smp_cross_call)
437                 __smp_cross_call = fn;
438 }
439
440 static const char *ipi_types[NR_IPI] __tracepoint_string = {
441 #define S(x,s)  [x] = s
442         S(IPI_WAKEUP, "CPU wakeup interrupts"),
443         S(IPI_TIMER, "Timer broadcast interrupts"),
444         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
445         S(IPI_CALL_FUNC, "Function call interrupts"),
446         S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
447         S(IPI_CPU_STOP, "CPU stop interrupts"),
448         S(IPI_IRQ_WORK, "IRQ work interrupts"),
449         S(IPI_COMPLETION, "completion interrupts"),
450 };
451
452 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
453 {
454         trace_ipi_raise(target, ipi_types[ipinr]);
455         __smp_cross_call(target, ipinr);
456 }
457
458 void show_ipi_list(struct seq_file *p, int prec)
459 {
460         unsigned int cpu, i;
461
462         for (i = 0; i < NR_IPI; i++) {
463                 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
464
465                 for_each_online_cpu(cpu)
466                         seq_printf(p, "%10u ",
467                                    __get_irq_stat(cpu, ipi_irqs[i]));
468
469                 seq_printf(p, " %s\n", ipi_types[i]);
470         }
471 }
472
473 u64 smp_irq_stat_cpu(unsigned int cpu)
474 {
475         u64 sum = 0;
476         int i;
477
478         for (i = 0; i < NR_IPI; i++)
479                 sum += __get_irq_stat(cpu, ipi_irqs[i]);
480
481         return sum;
482 }
483
484 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
485 {
486         smp_cross_call(mask, IPI_CALL_FUNC);
487 }
488
489 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
490 {
491         smp_cross_call(mask, IPI_WAKEUP);
492 }
493
494 void arch_send_call_function_single_ipi(int cpu)
495 {
496         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
497 }
498
499 #ifdef CONFIG_IRQ_WORK
500 void arch_irq_work_raise(void)
501 {
502         if (arch_irq_work_has_interrupt())
503                 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
504 }
505 #endif
506
507 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
508 void tick_broadcast(const struct cpumask *mask)
509 {
510         smp_cross_call(mask, IPI_TIMER);
511 }
512 #endif
513
514 static DEFINE_RAW_SPINLOCK(stop_lock);
515
516 /*
517  * ipi_cpu_stop - handle IPI from smp_send_stop()
518  */
519 static void ipi_cpu_stop(unsigned int cpu)
520 {
521         if (system_state == SYSTEM_BOOTING ||
522             system_state == SYSTEM_RUNNING) {
523                 raw_spin_lock(&stop_lock);
524                 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
525                 dump_stack();
526                 raw_spin_unlock(&stop_lock);
527         }
528
529         set_cpu_online(cpu, false);
530
531         local_fiq_disable();
532         local_irq_disable();
533
534         while (1)
535                 cpu_relax();
536 }
537
538 static DEFINE_PER_CPU(struct completion *, cpu_completion);
539
540 int register_ipi_completion(struct completion *completion, int cpu)
541 {
542         per_cpu(cpu_completion, cpu) = completion;
543         return IPI_COMPLETION;
544 }
545
546 static void ipi_complete(unsigned int cpu)
547 {
548         complete(per_cpu(cpu_completion, cpu));
549 }
550
551 /*
552  * Main handler for inter-processor interrupts
553  */
554 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
555 {
556         handle_IPI(ipinr, regs);
557 }
558
559 void handle_IPI(int ipinr, struct pt_regs *regs)
560 {
561         unsigned int cpu = smp_processor_id();
562         struct pt_regs *old_regs = set_irq_regs(regs);
563
564         if ((unsigned)ipinr < NR_IPI) {
565                 trace_ipi_entry(ipi_types[ipinr]);
566                 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
567         }
568
569         switch (ipinr) {
570         case IPI_WAKEUP:
571                 break;
572
573 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
574         case IPI_TIMER:
575                 irq_enter();
576                 tick_receive_broadcast();
577                 irq_exit();
578                 break;
579 #endif
580
581         case IPI_RESCHEDULE:
582                 scheduler_ipi();
583                 break;
584
585         case IPI_CALL_FUNC:
586                 irq_enter();
587                 generic_smp_call_function_interrupt();
588                 irq_exit();
589                 break;
590
591         case IPI_CALL_FUNC_SINGLE:
592                 irq_enter();
593                 generic_smp_call_function_single_interrupt();
594                 irq_exit();
595                 break;
596
597         case IPI_CPU_STOP:
598                 irq_enter();
599                 ipi_cpu_stop(cpu);
600                 irq_exit();
601                 break;
602
603 #ifdef CONFIG_IRQ_WORK
604         case IPI_IRQ_WORK:
605                 irq_enter();
606                 irq_work_run();
607                 irq_exit();
608                 break;
609 #endif
610
611         case IPI_COMPLETION:
612                 irq_enter();
613                 ipi_complete(cpu);
614                 irq_exit();
615                 break;
616
617         default:
618                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
619                        cpu, ipinr);
620                 break;
621         }
622
623         if ((unsigned)ipinr < NR_IPI)
624                 trace_ipi_exit(ipi_types[ipinr]);
625         set_irq_regs(old_regs);
626 }
627
628 void smp_send_reschedule(int cpu)
629 {
630         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
631 }
632
633 void smp_send_stop(void)
634 {
635         unsigned long timeout;
636         struct cpumask mask;
637
638         cpumask_copy(&mask, cpu_online_mask);
639         cpumask_clear_cpu(smp_processor_id(), &mask);
640         if (!cpumask_empty(&mask))
641                 smp_cross_call(&mask, IPI_CPU_STOP);
642
643         /* Wait up to one second for other CPUs to stop */
644         timeout = USEC_PER_SEC;
645         while (num_online_cpus() > 1 && timeout--)
646                 udelay(1);
647
648         if (num_online_cpus() > 1)
649                 pr_warn("SMP: failed to stop secondary CPUs\n");
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                 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
689                                                 global_l_p_j_ref_freq,
690                                                 freq->new);
691                 per_cpu(cpu_data, cpu).loops_per_jiffy =
692                         cpufreq_scale(per_cpu(l_p_j_ref, cpu),
693                                         per_cpu(l_p_j_ref_freq, cpu),
694                                         freq->new);
695         }
696         return NOTIFY_OK;
697 }
698
699 static struct notifier_block cpufreq_notifier = {
700         .notifier_call  = cpufreq_callback,
701 };
702
703 static int __init register_cpufreq_notifier(void)
704 {
705         return cpufreq_register_notifier(&cpufreq_notifier,
706                                                 CPUFREQ_TRANSITION_NOTIFIER);
707 }
708 core_initcall(register_cpufreq_notifier);
709
710 #endif