summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/smp.c
blob: 5c330c3366e42e2ec500cd8fe98fbdd7c94c3bc8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
/*
 * SMP support for ppc.
 *
 * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
 * deal of code from the sparc and intel versions.
 *
 * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
 *
 * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#undef DEBUG

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/notifier.h>

#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/system.h>
#include <asm/mpic.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#endif

int smp_hw_index[NR_CPUS];
struct thread_info *secondary_ti;

#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

cpumask_t cpu_possible_map = CPU_MASK_NONE;
cpumask_t cpu_online_map = CPU_MASK_NONE;
cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE };

EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL(cpu_possible_map);

/* SMP operations for this machine */
struct smp_ops_t *smp_ops;

static volatile unsigned int cpu_callin_map[NR_CPUS];

void smp_call_function_interrupt(void);

int smt_enabled_at_boot = 1;

#ifdef CONFIG_MPIC
int __init smp_mpic_probe(void)
{
	int nr_cpus;

	DBG("smp_mpic_probe()...\n");

	nr_cpus = cpus_weight(cpu_possible_map);

	DBG("nr_cpus: %d\n", nr_cpus);

	if (nr_cpus > 1)
		mpic_request_ipis();

	return nr_cpus;
}

void __devinit smp_mpic_setup_cpu(int cpu)
{
	mpic_setup_this_cpu();
}
#endif /* CONFIG_MPIC */

#ifdef CONFIG_PPC64
void __devinit smp_generic_kick_cpu(int nr)
{
	BUG_ON(nr < 0 || nr >= NR_CPUS);

	/*
	 * The processor is currently spinning, waiting for the
	 * cpu_start field to become non-zero After we set cpu_start,
	 * the processor will continue on to secondary_start
	 */
	paca[nr].cpu_start = 1;
	smp_mb();
}
#endif

void smp_message_recv(int msg, struct pt_regs *regs)
{
	switch(msg) {
	case PPC_MSG_CALL_FUNCTION:
		smp_call_function_interrupt();
		break;
	case PPC_MSG_RESCHEDULE:
		/* XXX Do we have to do this? */
		set_need_resched();
		break;
#ifdef CONFIG_DEBUGGER
	case PPC_MSG_DEBUGGER_BREAK:
		debugger_ipi(regs);
		break;
#endif
	default:
		printk("SMP %d: smp_message_recv(): unknown msg %d\n",
		       smp_processor_id(), msg);
		break;
	}
}

void smp_send_reschedule(int cpu)
{
	smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
}

#ifdef CONFIG_DEBUGGER
void smp_send_debugger_break(int cpu)
{
	smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
}
#endif

static void stop_this_cpu(void *dummy)
{
	local_irq_disable();
	while (1)
		;
}

void smp_send_stop(void)
{
	smp_call_function(stop_this_cpu, NULL, 1, 0);
}

/*
 * Structure and data for smp_call_function(). This is designed to minimise
 * static memory requirements. It also looks cleaner.
 * Stolen from the i386 version.
 */
static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);

static struct call_data_struct {
	void (*func) (void *info);
	void *info;
	atomic_t started;
	atomic_t finished;
	int wait;
} *call_data;

/* delay of at least 8 seconds */
#define SMP_CALL_TIMEOUT	8

/*
 * This function sends a 'generic call function' IPI to all other CPUs
 * in the system.
 *
 * [SUMMARY] Run a function on all other CPUs.
 * <func> The function to run. This must be fast and non-blocking.
 * <info> An arbitrary pointer to pass to the function.
 * <nonatomic> currently unused.
 * <wait> If true, wait (atomically) until function has completed on other CPUs.
 * [RETURNS] 0 on success, else a negative status code. Does not return until
 * remote CPUs are nearly ready to execute <<func>> or are or have executed.
 *
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.
 */
int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
		       int wait)
{ 
	struct call_data_struct data;
	int ret = -1, cpus;
	u64 timeout;

	/* Can deadlock when called with interrupts disabled */
	WARN_ON(irqs_disabled());

	data.func = func;
	data.info = info;
	atomic_set(&data.started, 0);
	data.wait = wait;
	if (wait)
		atomic_set(&data.finished, 0);

	spin_lock(&call_lock);
	/* Must grab online cpu count with preempt disabled, otherwise
	 * it can change. */
	cpus = num_online_cpus() - 1;
	if (!cpus) {
		ret = 0;
		goto out;
	}

	call_data = &data;
	smp_wmb();
	/* Send a message to all other CPUs and wait for them to respond */
	smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION);

	timeout = get_tb() + (u64) SMP_CALL_TIMEOUT * tb_ticks_per_sec;

	/* Wait for response */
	while (atomic_read(&data.started) != cpus) {
		HMT_low();
		if (get_tb() >= timeout) {
			printk("smp_call_function on cpu %d: other cpus not "
			       "responding (%d)\n", smp_processor_id(),
			       atomic_read(&data.started));
			debugger(NULL);
			goto out;
		}
	}

	if (wait) {
		while (atomic_read(&data.finished) != cpus) {
			HMT_low();
			if (get_tb() >= timeout) {
				printk("smp_call_function on cpu %d: other "
				       "cpus not finishing (%d/%d)\n",
				       smp_processor_id(),
				       atomic_read(&data.finished),
				       atomic_read(&data.started));
				debugger(NULL);
				goto out;
			}
		}
	}

	ret = 0;

 out:
	call_data = NULL;
	HMT_medium();
	spin_unlock(&call_lock);
	return ret;
}

EXPORT_SYMBOL(smp_call_function);

void smp_call_function_interrupt(void)
{
	void (*func) (void *info);
	void *info;
	int wait;

	/* call_data will be NULL if the sender timed out while
	 * waiting on us to receive the call.
	 */
	if (!call_data)
		return;

	func = call_data->func;
	info = call_data->info;
	wait = call_data->wait;

	if (!wait)
		smp_mb__before_atomic_inc();

	/*
	 * Notify initiating CPU that I've grabbed the data and am
	 * about to execute the function
	 */
	atomic_inc(&call_data->started);
	/*
	 * At this point the info structure may be out of scope unless wait==1
	 */
	(*func)(info);
	if (wait) {
		smp_mb__before_atomic_inc();
		atomic_inc(&call_data->finished);
	}
}

extern struct gettimeofday_struct do_gtod;

struct thread_info *current_set[NR_CPUS];

DECLARE_PER_CPU(unsigned int, pvr);

static void __devinit smp_store_cpu_info(int id)
{
	per_cpu(pvr, id) = mfspr(SPRN_PVR);
}

static void __init smp_create_idle(unsigned int cpu)
{
	struct task_struct *p;

	/* create a process for the processor */
	p = fork_idle(cpu);
	if (IS_ERR(p))
		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
#ifdef CONFIG_PPC64
	paca[cpu].__current = p;
#endif
	current_set[cpu] = p->thread_info;
	p->thread_info->cpu = cpu;
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
	unsigned int cpu;

	DBG("smp_prepare_cpus\n");

	/* 
	 * setup_cpu may need to be called on the boot cpu. We havent
	 * spun any cpus up but lets be paranoid.
	 */
	BUG_ON(boot_cpuid != smp_processor_id());

	/* Fixup boot cpu */
	smp_store_cpu_info(boot_cpuid);
	cpu_callin_map[boot_cpuid] = 1;

	max_cpus = smp_ops->probe();
 
	smp_space_timers(max_cpus);

	for_each_cpu(cpu)
		if (cpu != boot_cpuid)
			smp_create_idle(cpu);
}

void __devinit smp_prepare_boot_cpu(void)
{
	BUG_ON(smp_processor_id() != boot_cpuid);

	cpu_set(boot_cpuid, cpu_online_map);
#ifdef CONFIG_PPC64
	paca[boot_cpuid].__current = current;
#endif
	current_set[boot_cpuid] = current->thread_info;
}

#ifdef CONFIG_HOTPLUG_CPU
/* State of each CPU during hotplug phases */
DEFINE_PER_CPU(int, cpu_state) = { 0 };

int generic_cpu_disable(void)
{
	unsigned int cpu = smp_processor_id();

	if (cpu == boot_cpuid)
		return -EBUSY;

	systemcfg->processorCount--;
	cpu_clear(cpu, cpu_online_map);
	fixup_irqs(cpu_online_map);
	return 0;
}

int generic_cpu_enable(unsigned int cpu)
{
	/* Do the normal bootup if we haven't
	 * already bootstrapped. */
	if (system_state != SYSTEM_RUNNING)
		return -ENOSYS;

	/* get the target out of it's holding state */
	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
	smp_wmb();

	while (!cpu_online(cpu))
		cpu_relax();

	fixup_irqs(cpu_online_map);
	/* counter the irq disable in fixup_irqs */
	local_irq_enable();
	return 0;
}

void generic_cpu_die(unsigned int cpu)
{
	int i;

	for (i = 0; i < 100; i++) {
		smp_rmb();
		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
			return;
		msleep(100);
	}
	printk(KERN_ERR "CPU%d didn't die...\n", cpu);
}

void generic_mach_cpu_die(void)
{
	unsigned int cpu;

	local_irq_disable();
	cpu = smp_processor_id();
	printk(KERN_DEBUG "CPU%d offline\n", cpu);
	__get_cpu_var(cpu_state) = CPU_DEAD;
	smp_wmb();
	while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
		cpu_relax();

	flush_tlb_pending();
	cpu_set(cpu, cpu_online_map);
	local_irq_enable();
}
#endif

static int __devinit cpu_enable(unsigned int cpu)
{
	if (smp_ops->cpu_enable)
		return smp_ops->cpu_enable(cpu);

	return -ENOSYS;
}

int __devinit __cpu_up(unsigned int cpu)
{
	int c;

	secondary_ti = current_set[cpu];
	if (!cpu_enable(cpu))
		return 0;

	if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))
		return -EINVAL;

#ifdef CONFIG_PPC64
	paca[cpu].default_decr = tb_ticks_per_jiffy;
#endif

	/* Make sure callin-map entry is 0 (can be leftover a CPU
	 * hotplug
	 */
	cpu_callin_map[cpu] = 0;

	/* The information for processor bringup must
	 * be written out to main store before we release
	 * the processor.
	 */
	smp_mb();

	/* wake up cpus */
	DBG("smp: kicking cpu %d\n", cpu);
	smp_ops->kick_cpu(cpu);

	/*
	 * wait to see if the cpu made a callin (is actually up).
	 * use this value that I found through experimentation.
	 * -- Cort
	 */
	if (system_state < SYSTEM_RUNNING)
		for (c = 5000; c && !cpu_callin_map[cpu]; c--)
			udelay(100);
#ifdef CONFIG_HOTPLUG_CPU
	else
		/*
		 * CPUs can take much longer to come up in the
		 * hotplug case.  Wait five seconds.
		 */
		for (c = 25; c && !cpu_callin_map[cpu]; c--) {
			msleep(200);
		}
#endif

	if (!cpu_callin_map[cpu]) {
		printk("Processor %u is stuck.\n", cpu);
		return -ENOENT;
	}

	printk("Processor %u found.\n", cpu);

	if (smp_ops->give_timebase)
		smp_ops->give_timebase();

	/* Wait until cpu puts itself in the online map */
	while (!cpu_online(cpu))
		cpu_relax();

	return 0;
}


/* Activate a secondary processor. */
int __devinit start_secondary(void *unused)
{
	unsigned int cpu = smp_processor_id();

	atomic_inc(&init_mm.mm_count);
	current->active_mm = &init_mm;

	smp_store_cpu_info(cpu);
	set_dec(tb_ticks_per_jiffy);
	cpu_callin_map[cpu] = 1;

	smp_ops->setup_cpu(cpu);
	if (smp_ops->take_timebase)
		smp_ops->take_timebase();

	spin_lock(&call_lock);
	cpu_set(cpu, cpu_online_map);
	spin_unlock(&call_lock);

	local_irq_enable();

	cpu_idle();
	return 0;
}

int setup_profiling_timer(unsigned int multiplier)
{
	return 0;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
	cpumask_t old_mask;

	/* We want the setup_cpu() here to be called from CPU 0, but our
	 * init thread may have been "borrowed" by another CPU in the meantime
	 * se we pin us down to CPU 0 for a short while
	 */
	old_mask = current->cpus_allowed;
	set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
	
	smp_ops->setup_cpu(boot_cpuid);

	set_cpus_allowed(current, old_mask);
}

#ifdef CONFIG_HOTPLUG_CPU
int __cpu_disable(void)
{
	if (smp_ops->cpu_disable)
		return smp_ops->cpu_disable();

	return -ENOSYS;
}

void __cpu_die(unsigned int cpu)
{
	if (smp_ops->cpu_die)
		smp_ops->cpu_die(cpu);
}
#endif
OpenPOWER on IntegriCloud