smp.c 16.9 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
/*
 *  linux/arch/arm/kernel/smp.c
 *
 *  Copyright (C) 2002 ARM Limited, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
Russell King's avatar
Russell King committed
10
#include <linux/module.h>
Linus Torvalds's avatar
Linus Torvalds committed
11
12
13
14
15
16
17
18
19
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/cache.h>
#include <linux/profile.h>
#include <linux/errno.h>
#include <linux/mm.h>
Alexey Dobriyan's avatar
Alexey Dobriyan committed
20
#include <linux/err.h>
Linus Torvalds's avatar
Linus Torvalds committed
21
22
#include <linux/cpu.h>
#include <linux/seq_file.h>
Russell King's avatar
Russell King committed
23
#include <linux/irq.h>
24
#include <linux/nmi.h>
25
26
#include <linux/percpu.h>
#include <linux/clockchips.h>
27
#include <linux/completion.h>
28
#include <linux/cpufreq.h>
29
#include <linux/irq_work.h>
Linus Torvalds's avatar
Linus Torvalds committed
30

Arun Sharma's avatar
Arun Sharma committed
31
#include <linux/atomic.h>
32
#include <asm/smp.h>
Linus Torvalds's avatar
Linus Torvalds committed
33
34
#include <asm/cacheflush.h>
#include <asm/cpu.h>
35
#include <asm/cputype.h>
36
#include <asm/exception.h>
37
#include <asm/idmap.h>
38
#include <asm/topology.h>
39
40
41
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
Linus Torvalds's avatar
Linus Torvalds committed
42
#include <asm/processor.h>
43
#include <asm/sections.h>
Linus Torvalds's avatar
Linus Torvalds committed
44
45
#include <asm/tlbflush.h>
#include <asm/ptrace.h>
46
#include <asm/smp_plat.h>
47
#include <asm/virt.h>
48
#include <asm/mach/arch.h>
49
#include <asm/mpu.h>
Linus Torvalds's avatar
Linus Torvalds committed
50

Nicolas Pitre's avatar
Nicolas Pitre committed
51
52
53
#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>

54
55
56
57
58
59
60
/*
 * as from 2.5, kernels no longer have an init_tasks structure
 * so we need some other way of telling a new secondary core
 * where to place its SVC stack
 */
struct secondary_data secondary_data;

61
62
63
64
/*
 * control for which core is the next to come out of the secondary
 * boot "holding pen"
 */
65
volatile int pen_release = -1;
66

Linus Torvalds's avatar
Linus Torvalds committed
67
enum ipi_msg_type {
68
69
	IPI_WAKEUP,
	IPI_TIMER,
Linus Torvalds's avatar
Linus Torvalds committed
70
71
72
	IPI_RESCHEDULE,
	IPI_CALL_FUNC,
	IPI_CPU_STOP,
73
	IPI_IRQ_WORK,
74
	IPI_COMPLETION,
75
76
77
78
79
80
	IPI_CPU_BACKTRACE,
	/*
	 * SGI8-15 can be reserved by secure firmware, and thus may
	 * not be usable by the kernel. Please keep the above limited
	 * to at most 8 entries.
	 */
Linus Torvalds's avatar
Linus Torvalds committed
81
82
};

83
84
static DECLARE_COMPLETION(cpu_running);

85
static struct smp_operations smp_ops __ro_after_init;
86

87
void __init smp_set_ops(const struct smp_operations *ops)
88
89
90
91
92
{
	if (ops)
		smp_ops = *ops;
};

93
94
static unsigned long get_arch_pgd(pgd_t *pgd)
{
95
96
97
98
99
#ifdef CONFIG_ARM_LPAE
	return __phys_to_pfn(virt_to_phys(pgd));
#else
	return virt_to_phys(pgd);
#endif
100
101
}

102
int __cpu_up(unsigned int cpu, struct task_struct *idle)
Linus Torvalds's avatar
Linus Torvalds committed
103
104
105
{
	int ret;

106
107
108
	if (!smp_ops.smp_boot_secondary)
		return -ENOSYS;

109
110
111
112
	/*
	 * We need to tell the secondary core where to find
	 * its stack and the page tables.
	 */
Al Viro's avatar
Al Viro committed
113
	secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
114
115
116
117
#ifdef CONFIG_ARM_MPU
	secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr;
#endif

118
#ifdef CONFIG_MMU
119
	secondary_data.pgdir = virt_to_phys(idmap_pgd);
120
	secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
121
#endif
122
	sync_cache_w(&secondary_data);
123

Linus Torvalds's avatar
Linus Torvalds committed
124
125
126
	/*
	 * Now bring the CPU into our world.
	 */
127
	ret = smp_ops.smp_boot_secondary(cpu, idle);
128
129
130
131
132
	if (ret == 0) {
		/*
		 * CPU was successfully started, wait for it
		 * to come online or time out.
		 */
133
134
		wait_for_completion_timeout(&cpu_running,
						 msecs_to_jiffies(1000));
135

136
137
		if (!cpu_online(cpu)) {
			pr_crit("CPU%u: failed to come online\n", cpu);
138
			ret = -EIO;
139
140
141
		}
	} else {
		pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
142
143
144
	}


145
	memset(&secondary_data, 0, sizeof(secondary_data));
Linus Torvalds's avatar
Linus Torvalds committed
146
147
148
	return ret;
}

149
/* platform specific SMP operations */
150
void __init smp_init_cpus(void)
151
152
153
154
155
{
	if (smp_ops.smp_init_cpus)
		smp_ops.smp_init_cpus();
}

156
157
158
159
160
int platform_can_secondary_boot(void)
{
	return !!smp_ops.smp_boot_secondary;
}

161
162
163
164
165
166
167
168
169
170
int platform_can_cpu_hotplug(void)
{
#ifdef CONFIG_HOTPLUG_CPU
	if (smp_ops.cpu_kill)
		return 1;
#endif

	return 0;
}

171
#ifdef CONFIG_HOTPLUG_CPU
172
static int platform_cpu_kill(unsigned int cpu)
173
174
175
176
177
178
{
	if (smp_ops.cpu_kill)
		return smp_ops.cpu_kill(cpu);
	return 1;
}

179
static int platform_cpu_disable(unsigned int cpu)
180
181
182
183
{
	if (smp_ops.cpu_disable)
		return smp_ops.cpu_disable(cpu);

184
185
186
187
188
189
190
191
192
193
194
195
	return 0;
}

int platform_can_hotplug_cpu(unsigned int cpu)
{
	/* cpu_die must be specified to support hotplug */
	if (!smp_ops.cpu_die)
		return 0;

	if (smp_ops.cpu_can_disable)
		return smp_ops.cpu_can_disable(cpu);

196
197
198
199
200
	/*
	 * By default, allow disabling all CPUs except the first one,
	 * since this is special on a lot of platforms, e.g. because
	 * of clock tick interrupts.
	 */
201
	return cpu != 0;
202
}
203

204
205
206
/*
 * __cpu_disable runs on the processor to be shutdown.
 */
207
int __cpu_disable(void)
208
209
210
211
{
	unsigned int cpu = smp_processor_id();
	int ret;

212
	ret = platform_cpu_disable(cpu);
213
214
215
216
217
218
219
	if (ret)
		return ret;

	/*
	 * Take this CPU offline.  Once we clear this, we can't return,
	 * and we must not schedule until we're ready to give up the cpu.
	 */
220
	set_cpu_online(cpu, false);
221
222
223
224
225
226
227
228
229

	/*
	 * OK - migrate IRQs away from this CPU
	 */
	migrate_irqs();

	/*
	 * Flush user cache and TLB mappings, and then remove this CPU
	 * from the vm mask set of all processes.
230
231
232
	 *
	 * Caches are flushed to the Level of Unification Inner Shareable
	 * to write-back dirty lines to unified caches shared by all CPUs.
233
	 */
234
	flush_cache_louis();
235
236
	local_flush_tlb_all();

237
	clear_tasks_mm_cpumask(cpu);
238
239
240
241

	return 0;
}

242
243
static DECLARE_COMPLETION(cpu_died);

244
245
246
247
/*
 * called on the thread which is asking for a CPU to be shutdown -
 * waits until shutdown has completed, or it is timed out.
 */
248
void __cpu_die(unsigned int cpu)
249
{
250
251
252
253
	if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
		pr_err("CPU%u: cpu didn't die\n", cpu);
		return;
	}
254
	pr_debug("CPU%u: shutdown\n", cpu);
255

256
257
258
259
260
261
262
	/*
	 * platform_cpu_kill() is generally expected to do the powering off
	 * and/or cutting of clocks to the dying CPU.  Optionally, this may
	 * be done by the CPU which is dying in preference to supporting
	 * this call, but that means there is _no_ synchronisation between
	 * the requesting CPU and the dying CPU actually losing power.
	 */
263
	if (!platform_cpu_kill(cpu))
264
		pr_err("CPU%u: unable to kill\n", cpu);
265
266
267
268
269
270
271
272
273
274
}

/*
 * Called from the idle thread for the CPU which has been shutdown.
 *
 * Note that we disable IRQs here, but do not re-enable them
 * before returning to the caller. This is also the behaviour
 * of the other hotplug-cpu capable cores, so presumably coming
 * out of idle fixes this.
 */
275
void arch_cpu_idle_dead(void)
276
277
278
279
280
{
	unsigned int cpu = smp_processor_id();

	idle_task_exit();

281
282
	local_irq_disable();

283
284
285
286
287
288
289
290
291
292
293
294
295
	/*
	 * Flush the data out of the L1 cache for this CPU.  This must be
	 * before the completion to ensure that data is safely written out
	 * before platform_cpu_kill() gets called - which may disable
	 * *this* CPU and power down its cache.
	 */
	flush_cache_louis();

	/*
	 * Tell __cpu_die() that this CPU is now safe to dispose of.  Once
	 * this returns, power and/or clocks can be removed at any point
	 * from this CPU and its cache by platform_cpu_kill().
	 */
296
	complete(&cpu_died);
297

298
	/*
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
	 * Ensure that the cache lines associated with that completion are
	 * written out.  This covers the case where _this_ CPU is doing the
	 * powering down, to ensure that the completion is visible to the
	 * CPU waiting for this one.
	 */
	flush_cache_louis();

	/*
	 * The actual CPU shutdown procedure is at least platform (if not
	 * CPU) specific.  This may remove power, or it may simply spin.
	 *
	 * Platforms are generally expected *NOT* to return from this call,
	 * although there are some which do because they have no way to
	 * power down the CPU.  These platforms are the _only_ reason we
	 * have a return path which uses the fragment of assembly below.
	 *
	 * The return path should not be used for platforms which can
	 * power off the CPU.
317
	 */
318
319
	if (smp_ops.cpu_die)
		smp_ops.cpu_die(cpu);
320

321
322
323
	pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
		cpu);

324
325
326
327
328
329
	/*
	 * Do not return to the idle loop - jump back to the secondary
	 * cpu initialisation.  There's some initialisation which needs
	 * to be repeated to undo the effects of taking the CPU offline.
	 */
	__asm__("mov	sp, %0\n"
330
	"	mov	fp, #0\n"
331
332
	"	b	secondary_start_kernel"
		:
Al Viro's avatar
Al Viro committed
333
		: "r" (task_stack_page(current) + THREAD_SIZE - 8));
334
335
336
}
#endif /* CONFIG_HOTPLUG_CPU */

337
338
339
340
/*
 * Called by both boot and secondaries to move global data into
 * per-processor storage.
 */
341
static void smp_store_cpu_info(unsigned int cpuid)
342
343
344
345
{
	struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);

	cpu_info->loops_per_jiffy = loops_per_jiffy;
346
	cpu_info->cpuid = read_cpuid_id();
347
348

	store_cpu_topology(cpuid);
349
350
}

351
352
353
354
/*
 * This is the secondary CPU boot entry.  We're using this CPUs
 * idle thread stack, but a set of temporary page tables.
 */
355
asmlinkage void secondary_start_kernel(void)
356
357
{
	struct mm_struct *mm = &init_mm;
358
359
360
361
362
363
364
	unsigned int cpu;

	/*
	 * The identity mapping is uncached (strongly ordered), so
	 * switch away from it before attempting any exclusive accesses.
	 */
	cpu_switch_mm(mm->pgd, mm);
365
	local_flush_bp_all();
366
367
	enter_lazy_tlb(mm, current);
	local_flush_tlb_all();
368
369
370
371
372

	/*
	 * All kernel threads share the same mm context; grab a
	 * reference and switch to it.
	 */
373
	cpu = smp_processor_id();
Vegard Nossum's avatar
Vegard Nossum committed
374
	mmgrab(mm);
375
	current->active_mm = mm;
376
	cpumask_set_cpu(cpu, mm_cpumask(mm));
377

378
379
	cpu_init();

380
	pr_debug("CPU%u: Booted secondary processor\n", cpu);
381

382
	preempt_disable();
383
	trace_hardirqs_off();
384
385
386
387

	/*
	 * Give the platform a chance to do its own initialisation.
	 */
388
389
	if (smp_ops.smp_secondary_init)
		smp_ops.smp_secondary_init(cpu);
390

391
	notify_cpu_starting(cpu);
392

393
394
395
396
397
	calibrate_delay();

	smp_store_cpu_info(cpu);

	/*
398
399
	 * OK, now it's safe to let the boot CPU continue.  Wait for
	 * the CPU migration code to notice that the CPU is online
400
	 * before we continue - which happens after __cpu_up returns.
401
	 */
402
	set_cpu_online(cpu, true);
403
	complete(&cpu_running);
404
405
406

	local_irq_enable();
	local_fiq_enable();
407
	local_abt_enable();
408

409
410
411
	/*
	 * OK, it's off to the idle thread for us
	 */
412
	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
413
414
}

Linus Torvalds's avatar
Linus Torvalds committed
415
416
void __init smp_cpus_done(unsigned int max_cpus)
{
417
418
419
420
421
422
423
424
425
426
427
428
	int cpu;
	unsigned long bogosum = 0;

	for_each_online_cpu(cpu)
		bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;

	printk(KERN_INFO "SMP: Total of %d processors activated "
	       "(%lu.%02lu BogoMIPS).\n",
	       num_online_cpus(),
	       bogosum / (500000/HZ),
	       (bogosum / (5000/HZ)) % 100);

429
	hyp_mode_check();
Linus Torvalds's avatar
Linus Torvalds committed
430
431
432
433
}

void __init smp_prepare_boot_cpu(void)
{
434
	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
Linus Torvalds's avatar
Linus Torvalds committed
435
436
}

437
void __init smp_prepare_cpus(unsigned int max_cpus)
Linus Torvalds's avatar
Linus Torvalds committed
438
{
439
	unsigned int ncores = num_possible_cpus();
Linus Torvalds's avatar
Linus Torvalds committed
440

441
442
	init_cpu_topology();

443
	smp_store_cpu_info(smp_processor_id());
Linus Torvalds's avatar
Linus Torvalds committed
444
445

	/*
446
	 * are we trying to boot more cores than exist?
Linus Torvalds's avatar
Linus Torvalds committed
447
	 */
448
449
	if (max_cpus > ncores)
		max_cpus = ncores;
450
451
452
453
	if (ncores > 1 && max_cpus) {
		/*
		 * Initialise the present map, which describes the set of CPUs
		 * actually populated at the present time. A platform should
454
455
		 * re-initialize the map in the platforms smp_prepare_cpus()
		 * if present != possible (e.g. physical hotplug).
456
		 */
457
		init_cpu_present(cpu_possible_mask);
458

459
460
461
462
		/*
		 * Initialise the SCU if there are more than one CPU
		 * and let them know where to start.
		 */
463
464
		if (smp_ops.smp_prepare_cpus)
			smp_ops.smp_prepare_cpus(max_cpus);
465
	}
Linus Torvalds's avatar
Linus Torvalds committed
466
467
}

Nicolas Pitre's avatar
Nicolas Pitre committed
468
static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
469
470
471

void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
{
Nicolas Pitre's avatar
Nicolas Pitre committed
472
473
	if (!__smp_cross_call)
		__smp_cross_call = fn;
474
475
}

Nicolas Pitre's avatar
Nicolas Pitre committed
476
static const char *ipi_types[NR_IPI] __tracepoint_string = {
477
478
#define S(x,s)	[x] = s
	S(IPI_WAKEUP, "CPU wakeup interrupts"),
479
480
481
482
	S(IPI_TIMER, "Timer broadcast interrupts"),
	S(IPI_RESCHEDULE, "Rescheduling interrupts"),
	S(IPI_CALL_FUNC, "Function call interrupts"),
	S(IPI_CPU_STOP, "CPU stop interrupts"),
483
	S(IPI_IRQ_WORK, "IRQ work interrupts"),
484
	S(IPI_COMPLETION, "completion interrupts"),
485
486
};

Nicolas Pitre's avatar
Nicolas Pitre committed
487
488
static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
{
489
	trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
Nicolas Pitre's avatar
Nicolas Pitre committed
490
491
492
	__smp_cross_call(target, ipinr);
}

493
void show_ipi_list(struct seq_file *p, int prec)
Linus Torvalds's avatar
Linus Torvalds committed
494
{
495
	unsigned int cpu, i;
Linus Torvalds's avatar
Linus Torvalds committed
496

497
498
	for (i = 0; i < NR_IPI; i++) {
		seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
Linus Torvalds's avatar
Linus Torvalds committed
499

500
		for_each_online_cpu(cpu)
501
502
			seq_printf(p, "%10u ",
				   __get_irq_stat(cpu, ipi_irqs[i]));
Linus Torvalds's avatar
Linus Torvalds committed
503

504
505
		seq_printf(p, " %s\n", ipi_types[i]);
	}
Linus Torvalds's avatar
Linus Torvalds committed
506
507
}

508
u64 smp_irq_stat_cpu(unsigned int cpu)
509
{
510
511
	u64 sum = 0;
	int i;
512

513
514
	for (i = 0; i < NR_IPI; i++)
		sum += __get_irq_stat(cpu, ipi_irqs[i]);
515

516
	return sum;
517
518
}

Nicolas Pitre's avatar
Nicolas Pitre committed
519
520
521
522
523
524
525
526
527
528
529
530
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
	smp_cross_call(mask, IPI_CALL_FUNC);
}

void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
{
	smp_cross_call(mask, IPI_WAKEUP);
}

void arch_send_call_function_single_ipi(int cpu)
{
531
	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
Nicolas Pitre's avatar
Nicolas Pitre committed
532
533
534
535
536
}

#ifdef CONFIG_IRQ_WORK
void arch_irq_work_raise(void)
{
537
	if (arch_irq_work_has_interrupt())
Nicolas Pitre's avatar
Nicolas Pitre committed
538
539
540
541
		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
}
#endif

542
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
543
void tick_broadcast(const struct cpumask *mask)
544
{
545
	smp_cross_call(mask, IPI_TIMER);
546
}
547
#endif
548

549
static DEFINE_RAW_SPINLOCK(stop_lock);
Linus Torvalds's avatar
Linus Torvalds committed
550
551
552
553
554
555

/*
 * ipi_cpu_stop - handle IPI from smp_send_stop()
 */
static void ipi_cpu_stop(unsigned int cpu)
{
556
557
	if (system_state == SYSTEM_BOOTING ||
	    system_state == SYSTEM_RUNNING) {
558
		raw_spin_lock(&stop_lock);
559
		pr_crit("CPU%u: stopping\n", cpu);
560
		dump_stack();
561
		raw_spin_unlock(&stop_lock);
562
	}
Linus Torvalds's avatar
Linus Torvalds committed
563

564
	set_cpu_online(cpu, false);
Linus Torvalds's avatar
Linus Torvalds committed
565
566
567
568
569
570
571
572

	local_fiq_disable();
	local_irq_disable();

	while (1)
		cpu_relax();
}

573
574
575
576
577
578
579
580
581
582
583
584
585
static DEFINE_PER_CPU(struct completion *, cpu_completion);

int register_ipi_completion(struct completion *completion, int cpu)
{
	per_cpu(cpu_completion, cpu) = completion;
	return IPI_COMPLETION;
}

static void ipi_complete(unsigned int cpu)
{
	complete(per_cpu(cpu_completion, cpu));
}

Linus Torvalds's avatar
Linus Torvalds committed
586
587
588
/*
 * Main handler for inter-processor interrupts
 */
Russell King's avatar
Russell King committed
589
asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
590
591
592
593
594
{
	handle_IPI(ipinr, regs);
}

void handle_IPI(int ipinr, struct pt_regs *regs)
Linus Torvalds's avatar
Linus Torvalds committed
595
596
{
	unsigned int cpu = smp_processor_id();
Russell King's avatar
Russell King committed
597
	struct pt_regs *old_regs = set_irq_regs(regs);
Linus Torvalds's avatar
Linus Torvalds committed
598

Nicolas Pitre's avatar
Nicolas Pitre committed
599
	if ((unsigned)ipinr < NR_IPI) {
600
		trace_ipi_entry_rcuidle(ipi_types[ipinr]);
601
		__inc_irq_stat(cpu, ipi_irqs[ipinr]);
Nicolas Pitre's avatar
Nicolas Pitre committed
602
	}
Linus Torvalds's avatar
Linus Torvalds committed
603

604
	switch (ipinr) {
605
606
607
	case IPI_WAKEUP:
		break;

608
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
609
	case IPI_TIMER:
610
		irq_enter();
611
		tick_receive_broadcast();
612
		irq_exit();
613
		break;
614
#endif
Linus Torvalds's avatar
Linus Torvalds committed
615

616
	case IPI_RESCHEDULE:
617
		scheduler_ipi();
618
		break;
Linus Torvalds's avatar
Linus Torvalds committed
619

620
	case IPI_CALL_FUNC:
621
		irq_enter();
622
		generic_smp_call_function_interrupt();
623
		irq_exit();
624
		break;
Linus Torvalds's avatar
Linus Torvalds committed
625

626
	case IPI_CPU_STOP:
627
		irq_enter();
628
		ipi_cpu_stop(cpu);
629
		irq_exit();
630
		break;
Linus Torvalds's avatar
Linus Torvalds committed
631

632
633
634
635
636
637
638
639
#ifdef CONFIG_IRQ_WORK
	case IPI_IRQ_WORK:
		irq_enter();
		irq_work_run();
		irq_exit();
		break;
#endif

640
641
642
643
644
645
	case IPI_COMPLETION:
		irq_enter();
		ipi_complete(cpu);
		irq_exit();
		break;

646
	case IPI_CPU_BACKTRACE:
647
		printk_nmi_enter();
648
649
650
		irq_enter();
		nmi_cpu_backtrace(regs);
		irq_exit();
651
		printk_nmi_exit();
652
653
		break;

654
	default:
655
656
		pr_crit("CPU%u: Unknown IPI message 0x%x\n",
		        cpu, ipinr);
657
		break;
Linus Torvalds's avatar
Linus Torvalds committed
658
	}
Nicolas Pitre's avatar
Nicolas Pitre committed
659
660

	if ((unsigned)ipinr < NR_IPI)
661
		trace_ipi_exit_rcuidle(ipi_types[ipinr]);
Russell King's avatar
Russell King committed
662
	set_irq_regs(old_regs);
Linus Torvalds's avatar
Linus Torvalds committed
663
664
665
666
}

void smp_send_reschedule(int cpu)
{
667
	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
Linus Torvalds's avatar
Linus Torvalds committed
668
669
670
671
}

void smp_send_stop(void)
{
672
	unsigned long timeout;
673
	struct cpumask mask;
Linus Torvalds's avatar
Linus Torvalds committed
674

675
676
	cpumask_copy(&mask, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), &mask);
677
678
	if (!cpumask_empty(&mask))
		smp_cross_call(&mask, IPI_CPU_STOP);
679

680
681
682
683
	/* Wait up to one second for other CPUs to stop */
	timeout = USEC_PER_SEC;
	while (num_online_cpus() > 1 && timeout--)
		udelay(1);
684

685
	if (num_online_cpus() > 1)
686
		pr_warn("SMP: failed to stop secondary CPUs\n");
687
688
689
}

/*
Linus Torvalds's avatar
Linus Torvalds committed
690
 * not supported here
691
 */
692
int setup_profiling_timer(unsigned int multiplier)
693
{
Linus Torvalds's avatar
Linus Torvalds committed
694
	return -EINVAL;
695
}
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723

#ifdef CONFIG_CPU_FREQ

static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
static unsigned long global_l_p_j_ref;
static unsigned long global_l_p_j_ref_freq;

static int cpufreq_callback(struct notifier_block *nb,
					unsigned long val, void *data)
{
	struct cpufreq_freqs *freq = data;
	int cpu = freq->cpu;

	if (freq->flags & CPUFREQ_CONST_LOOPS)
		return NOTIFY_OK;

	if (!per_cpu(l_p_j_ref, cpu)) {
		per_cpu(l_p_j_ref, cpu) =
			per_cpu(cpu_data, cpu).loops_per_jiffy;
		per_cpu(l_p_j_ref_freq, cpu) = freq->old;
		if (!global_l_p_j_ref) {
			global_l_p_j_ref = loops_per_jiffy;
			global_l_p_j_ref_freq = freq->old;
		}
	}

	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
724
	    (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
		loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
						global_l_p_j_ref_freq,
						freq->new);
		per_cpu(cpu_data, cpu).loops_per_jiffy =
			cpufreq_scale(per_cpu(l_p_j_ref, cpu),
					per_cpu(l_p_j_ref_freq, cpu),
					freq->new);
	}
	return NOTIFY_OK;
}

static struct notifier_block cpufreq_notifier = {
	.notifier_call  = cpufreq_callback,
};

static int __init register_cpufreq_notifier(void)
{
	return cpufreq_register_notifier(&cpufreq_notifier,
						CPUFREQ_TRANSITION_NOTIFIER);
}
core_initcall(register_cpufreq_notifier);

#endif
748
749
750
751
752
753

static void raise_nmi(cpumask_t *mask)
{
	smp_cross_call(mask, IPI_CPU_BACKTRACE);
}

754
void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
755
{
756
	nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
757
}