xref: /linux/arch/powerpc/kernel/smp.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
1 /*
2  * SMP support for ppc.
3  *
4  * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
5  * deal of code from the sparc and intel versions.
6  *
7  * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
8  *
9  * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
10  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
11  *
12  *      This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  */
17 
18 #undef DEBUG
19 
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/sched.h>
23 #include <linux/smp.h>
24 #include <linux/interrupt.h>
25 #include <linux/delay.h>
26 #include <linux/init.h>
27 #include <linux/spinlock.h>
28 #include <linux/cache.h>
29 #include <linux/err.h>
30 #include <linux/sysdev.h>
31 #include <linux/cpu.h>
32 #include <linux/notifier.h>
33 #include <linux/topology.h>
34 
35 #include <asm/ptrace.h>
36 #include <asm/atomic.h>
37 #include <asm/irq.h>
38 #include <asm/page.h>
39 #include <asm/pgtable.h>
40 #include <asm/prom.h>
41 #include <asm/smp.h>
42 #include <asm/time.h>
43 #include <asm/machdep.h>
44 #include <asm/cputhreads.h>
45 #include <asm/cputable.h>
46 #include <asm/system.h>
47 #include <asm/mpic.h>
48 #include <asm/vdso_datapage.h>
49 #ifdef CONFIG_PPC64
50 #include <asm/paca.h>
51 #endif
52 
53 #ifdef DEBUG
54 #include <asm/udbg.h>
55 #define DBG(fmt...) udbg_printf(fmt)
56 #else
57 #define DBG(fmt...)
58 #endif
59 
60 struct thread_info *secondary_ti;
61 
62 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
63 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
64 
65 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
66 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
67 
68 /* SMP operations for this machine */
69 struct smp_ops_t *smp_ops;
70 
71 /* Can't be static due to PowerMac hackery */
72 volatile unsigned int cpu_callin_map[NR_CPUS];
73 
74 int smt_enabled_at_boot = 1;
75 
76 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
77 
78 #ifdef CONFIG_PPC64
79 void __devinit smp_generic_kick_cpu(int nr)
80 {
81 	BUG_ON(nr < 0 || nr >= NR_CPUS);
82 
83 	/*
84 	 * The processor is currently spinning, waiting for the
85 	 * cpu_start field to become non-zero After we set cpu_start,
86 	 * the processor will continue on to secondary_start
87 	 */
88 	paca[nr].cpu_start = 1;
89 	smp_mb();
90 }
91 #endif
92 
93 void smp_message_recv(int msg)
94 {
95 	switch(msg) {
96 	case PPC_MSG_CALL_FUNCTION:
97 		generic_smp_call_function_interrupt();
98 		break;
99 	case PPC_MSG_RESCHEDULE:
100 		/* we notice need_resched on exit */
101 		break;
102 	case PPC_MSG_CALL_FUNC_SINGLE:
103 		generic_smp_call_function_single_interrupt();
104 		break;
105 	case PPC_MSG_DEBUGGER_BREAK:
106 		if (crash_ipi_function_ptr) {
107 			crash_ipi_function_ptr(get_irq_regs());
108 			break;
109 		}
110 #ifdef CONFIG_DEBUGGER
111 		debugger_ipi(get_irq_regs());
112 		break;
113 #endif /* CONFIG_DEBUGGER */
114 		/* FALLTHROUGH */
115 	default:
116 		printk("SMP %d: smp_message_recv(): unknown msg %d\n",
117 		       smp_processor_id(), msg);
118 		break;
119 	}
120 }
121 
122 static irqreturn_t call_function_action(int irq, void *data)
123 {
124 	generic_smp_call_function_interrupt();
125 	return IRQ_HANDLED;
126 }
127 
128 static irqreturn_t reschedule_action(int irq, void *data)
129 {
130 	/* we just need the return path side effect of checking need_resched */
131 	return IRQ_HANDLED;
132 }
133 
134 static irqreturn_t call_function_single_action(int irq, void *data)
135 {
136 	generic_smp_call_function_single_interrupt();
137 	return IRQ_HANDLED;
138 }
139 
140 static irqreturn_t debug_ipi_action(int irq, void *data)
141 {
142 	smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
143 	return IRQ_HANDLED;
144 }
145 
146 static irq_handler_t smp_ipi_action[] = {
147 	[PPC_MSG_CALL_FUNCTION] =  call_function_action,
148 	[PPC_MSG_RESCHEDULE] = reschedule_action,
149 	[PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action,
150 	[PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
151 };
152 
153 const char *smp_ipi_name[] = {
154 	[PPC_MSG_CALL_FUNCTION] =  "ipi call function",
155 	[PPC_MSG_RESCHEDULE] = "ipi reschedule",
156 	[PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single",
157 	[PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
158 };
159 
160 /* optional function to request ipi, for controllers with >= 4 ipis */
161 int smp_request_message_ipi(int virq, int msg)
162 {
163 	int err;
164 
165 	if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
166 		return -EINVAL;
167 	}
168 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC)
169 	if (msg == PPC_MSG_DEBUGGER_BREAK) {
170 		return 1;
171 	}
172 #endif
173 	err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU,
174 			  smp_ipi_name[msg], 0);
175 	WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
176 		virq, smp_ipi_name[msg], err);
177 
178 	return err;
179 }
180 
181 void smp_send_reschedule(int cpu)
182 {
183 	if (likely(smp_ops))
184 		smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
185 }
186 
187 void arch_send_call_function_single_ipi(int cpu)
188 {
189 	smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
190 }
191 
192 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
193 {
194 	unsigned int cpu;
195 
196 	for_each_cpu(cpu, mask)
197 		smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
198 }
199 
200 #ifdef CONFIG_DEBUGGER
201 void smp_send_debugger_break(int cpu)
202 {
203 	if (likely(smp_ops))
204 		smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
205 }
206 #endif
207 
208 #ifdef CONFIG_KEXEC
209 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
210 {
211 	crash_ipi_function_ptr = crash_ipi_callback;
212 	if (crash_ipi_callback && smp_ops) {
213 		mb();
214 		smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
215 	}
216 }
217 #endif
218 
219 static void stop_this_cpu(void *dummy)
220 {
221 	/* Remove this CPU */
222 	set_cpu_online(smp_processor_id(), false);
223 
224 	local_irq_disable();
225 	while (1)
226 		;
227 }
228 
229 void smp_send_stop(void)
230 {
231 	smp_call_function(stop_this_cpu, NULL, 0);
232 }
233 
234 struct thread_info *current_set[NR_CPUS];
235 
236 static void __devinit smp_store_cpu_info(int id)
237 {
238 	per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
239 }
240 
241 static void __init smp_create_idle(unsigned int cpu)
242 {
243 	struct task_struct *p;
244 
245 	/* create a process for the processor */
246 	p = fork_idle(cpu);
247 	if (IS_ERR(p))
248 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
249 #ifdef CONFIG_PPC64
250 	paca[cpu].__current = p;
251 	paca[cpu].kstack = (unsigned long) task_thread_info(p)
252 		+ THREAD_SIZE - STACK_FRAME_OVERHEAD;
253 #endif
254 	current_set[cpu] = task_thread_info(p);
255 	task_thread_info(p)->cpu = cpu;
256 }
257 
258 void __init smp_prepare_cpus(unsigned int max_cpus)
259 {
260 	unsigned int cpu;
261 
262 	DBG("smp_prepare_cpus\n");
263 
264 	/*
265 	 * setup_cpu may need to be called on the boot cpu. We havent
266 	 * spun any cpus up but lets be paranoid.
267 	 */
268 	BUG_ON(boot_cpuid != smp_processor_id());
269 
270 	/* Fixup boot cpu */
271 	smp_store_cpu_info(boot_cpuid);
272 	cpu_callin_map[boot_cpuid] = 1;
273 
274 	for_each_possible_cpu(cpu) {
275 		zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
276 					GFP_KERNEL, cpu_to_node(cpu));
277 		zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
278 					GFP_KERNEL, cpu_to_node(cpu));
279 	}
280 
281 	cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
282 	cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
283 
284 	if (smp_ops)
285 		if (smp_ops->probe)
286 			max_cpus = smp_ops->probe();
287 		else
288 			max_cpus = NR_CPUS;
289 	else
290 		max_cpus = 1;
291 
292 	for_each_possible_cpu(cpu)
293 		if (cpu != boot_cpuid)
294 			smp_create_idle(cpu);
295 }
296 
297 void __devinit smp_prepare_boot_cpu(void)
298 {
299 	BUG_ON(smp_processor_id() != boot_cpuid);
300 #ifdef CONFIG_PPC64
301 	paca[boot_cpuid].__current = current;
302 #endif
303 	current_set[boot_cpuid] = task_thread_info(current);
304 }
305 
306 #ifdef CONFIG_HOTPLUG_CPU
307 /* State of each CPU during hotplug phases */
308 DEFINE_PER_CPU(int, cpu_state) = { 0 };
309 
310 int generic_cpu_disable(void)
311 {
312 	unsigned int cpu = smp_processor_id();
313 
314 	if (cpu == boot_cpuid)
315 		return -EBUSY;
316 
317 	set_cpu_online(cpu, false);
318 #ifdef CONFIG_PPC64
319 	vdso_data->processorCount--;
320 	fixup_irqs(cpu_online_mask);
321 #endif
322 	return 0;
323 }
324 
325 int generic_cpu_enable(unsigned int cpu)
326 {
327 	/* Do the normal bootup if we haven't
328 	 * already bootstrapped. */
329 	if (system_state != SYSTEM_RUNNING)
330 		return -ENOSYS;
331 
332 	/* get the target out of it's holding state */
333 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
334 	smp_wmb();
335 
336 	while (!cpu_online(cpu))
337 		cpu_relax();
338 
339 #ifdef CONFIG_PPC64
340 	fixup_irqs(cpu_online_mask);
341 	/* counter the irq disable in fixup_irqs */
342 	local_irq_enable();
343 #endif
344 	return 0;
345 }
346 
347 void generic_cpu_die(unsigned int cpu)
348 {
349 	int i;
350 
351 	for (i = 0; i < 100; i++) {
352 		smp_rmb();
353 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
354 			return;
355 		msleep(100);
356 	}
357 	printk(KERN_ERR "CPU%d didn't die...\n", cpu);
358 }
359 
360 void generic_mach_cpu_die(void)
361 {
362 	unsigned int cpu;
363 
364 	local_irq_disable();
365 	cpu = smp_processor_id();
366 	printk(KERN_DEBUG "CPU%d offline\n", cpu);
367 	__get_cpu_var(cpu_state) = CPU_DEAD;
368 	smp_wmb();
369 	while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
370 		cpu_relax();
371 	set_cpu_online(cpu, true);
372 	local_irq_enable();
373 }
374 #endif
375 
376 static int __devinit cpu_enable(unsigned int cpu)
377 {
378 	if (smp_ops && smp_ops->cpu_enable)
379 		return smp_ops->cpu_enable(cpu);
380 
381 	return -ENOSYS;
382 }
383 
384 int __cpuinit __cpu_up(unsigned int cpu)
385 {
386 	int c;
387 
388 	secondary_ti = current_set[cpu];
389 	if (!cpu_enable(cpu))
390 		return 0;
391 
392 	if (smp_ops == NULL ||
393 	    (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
394 		return -EINVAL;
395 
396 	/* Make sure callin-map entry is 0 (can be leftover a CPU
397 	 * hotplug
398 	 */
399 	cpu_callin_map[cpu] = 0;
400 
401 	/* The information for processor bringup must
402 	 * be written out to main store before we release
403 	 * the processor.
404 	 */
405 	smp_mb();
406 
407 	/* wake up cpus */
408 	DBG("smp: kicking cpu %d\n", cpu);
409 	smp_ops->kick_cpu(cpu);
410 
411 	/*
412 	 * wait to see if the cpu made a callin (is actually up).
413 	 * use this value that I found through experimentation.
414 	 * -- Cort
415 	 */
416 	if (system_state < SYSTEM_RUNNING)
417 		for (c = 50000; c && !cpu_callin_map[cpu]; c--)
418 			udelay(100);
419 #ifdef CONFIG_HOTPLUG_CPU
420 	else
421 		/*
422 		 * CPUs can take much longer to come up in the
423 		 * hotplug case.  Wait five seconds.
424 		 */
425 		for (c = 5000; c && !cpu_callin_map[cpu]; c--)
426 			msleep(1);
427 #endif
428 
429 	if (!cpu_callin_map[cpu]) {
430 		printk("Processor %u is stuck.\n", cpu);
431 		return -ENOENT;
432 	}
433 
434 	printk("Processor %u found.\n", cpu);
435 
436 	if (smp_ops->give_timebase)
437 		smp_ops->give_timebase();
438 
439 	/* Wait until cpu puts itself in the online map */
440 	while (!cpu_online(cpu))
441 		cpu_relax();
442 
443 	return 0;
444 }
445 
446 /* Return the value of the reg property corresponding to the given
447  * logical cpu.
448  */
449 int cpu_to_core_id(int cpu)
450 {
451 	struct device_node *np;
452 	const int *reg;
453 	int id = -1;
454 
455 	np = of_get_cpu_node(cpu, NULL);
456 	if (!np)
457 		goto out;
458 
459 	reg = of_get_property(np, "reg", NULL);
460 	if (!reg)
461 		goto out;
462 
463 	id = *reg;
464 out:
465 	of_node_put(np);
466 	return id;
467 }
468 
469 /* Must be called when no change can occur to cpu_present_mask,
470  * i.e. during cpu online or offline.
471  */
472 static struct device_node *cpu_to_l2cache(int cpu)
473 {
474 	struct device_node *np;
475 	struct device_node *cache;
476 
477 	if (!cpu_present(cpu))
478 		return NULL;
479 
480 	np = of_get_cpu_node(cpu, NULL);
481 	if (np == NULL)
482 		return NULL;
483 
484 	cache = of_find_next_cache_node(np);
485 
486 	of_node_put(np);
487 
488 	return cache;
489 }
490 
491 /* Activate a secondary processor. */
492 int __devinit start_secondary(void *unused)
493 {
494 	unsigned int cpu = smp_processor_id();
495 	struct device_node *l2_cache;
496 	int i, base;
497 
498 	atomic_inc(&init_mm.mm_count);
499 	current->active_mm = &init_mm;
500 
501 	smp_store_cpu_info(cpu);
502 	set_dec(tb_ticks_per_jiffy);
503 	preempt_disable();
504 	cpu_callin_map[cpu] = 1;
505 
506 	if (smp_ops->setup_cpu)
507 		smp_ops->setup_cpu(cpu);
508 	if (smp_ops->take_timebase)
509 		smp_ops->take_timebase();
510 
511 	if (system_state > SYSTEM_BOOTING)
512 		snapshot_timebase();
513 
514 	secondary_cpu_time_init();
515 
516 	ipi_call_lock();
517 	notify_cpu_starting(cpu);
518 	set_cpu_online(cpu, true);
519 	/* Update sibling maps */
520 	base = cpu_first_thread_in_core(cpu);
521 	for (i = 0; i < threads_per_core; i++) {
522 		if (cpu_is_offline(base + i))
523 			continue;
524 		cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
525 		cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
526 
527 		/* cpu_core_map should be a superset of
528 		 * cpu_sibling_map even if we don't have cache
529 		 * information, so update the former here, too.
530 		 */
531 		cpumask_set_cpu(cpu, cpu_core_mask(base + i));
532 		cpumask_set_cpu(base + i, cpu_core_mask(cpu));
533 	}
534 	l2_cache = cpu_to_l2cache(cpu);
535 	for_each_online_cpu(i) {
536 		struct device_node *np = cpu_to_l2cache(i);
537 		if (!np)
538 			continue;
539 		if (np == l2_cache) {
540 			cpumask_set_cpu(cpu, cpu_core_mask(i));
541 			cpumask_set_cpu(i, cpu_core_mask(cpu));
542 		}
543 		of_node_put(np);
544 	}
545 	of_node_put(l2_cache);
546 	ipi_call_unlock();
547 
548 	local_irq_enable();
549 
550 	cpu_idle();
551 	return 0;
552 }
553 
554 int setup_profiling_timer(unsigned int multiplier)
555 {
556 	return 0;
557 }
558 
559 void __init smp_cpus_done(unsigned int max_cpus)
560 {
561 	cpumask_var_t old_mask;
562 
563 	/* We want the setup_cpu() here to be called from CPU 0, but our
564 	 * init thread may have been "borrowed" by another CPU in the meantime
565 	 * se we pin us down to CPU 0 for a short while
566 	 */
567 	alloc_cpumask_var(&old_mask, GFP_NOWAIT);
568 	cpumask_copy(old_mask, &current->cpus_allowed);
569 	set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
570 
571 	if (smp_ops && smp_ops->setup_cpu)
572 		smp_ops->setup_cpu(boot_cpuid);
573 
574 	set_cpus_allowed_ptr(current, old_mask);
575 
576 	free_cpumask_var(old_mask);
577 
578 	snapshot_timebases();
579 
580 	dump_numa_cpu_topology();
581 }
582 
583 #ifdef CONFIG_HOTPLUG_CPU
584 int __cpu_disable(void)
585 {
586 	struct device_node *l2_cache;
587 	int cpu = smp_processor_id();
588 	int base, i;
589 	int err;
590 
591 	if (!smp_ops->cpu_disable)
592 		return -ENOSYS;
593 
594 	err = smp_ops->cpu_disable();
595 	if (err)
596 		return err;
597 
598 	/* Update sibling maps */
599 	base = cpu_first_thread_in_core(cpu);
600 	for (i = 0; i < threads_per_core; i++) {
601 		cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
602 		cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
603 		cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
604 		cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
605 	}
606 
607 	l2_cache = cpu_to_l2cache(cpu);
608 	for_each_present_cpu(i) {
609 		struct device_node *np = cpu_to_l2cache(i);
610 		if (!np)
611 			continue;
612 		if (np == l2_cache) {
613 			cpumask_clear_cpu(cpu, cpu_core_mask(i));
614 			cpumask_clear_cpu(i, cpu_core_mask(cpu));
615 		}
616 		of_node_put(np);
617 	}
618 	of_node_put(l2_cache);
619 
620 
621 	return 0;
622 }
623 
624 void __cpu_die(unsigned int cpu)
625 {
626 	if (smp_ops->cpu_die)
627 		smp_ops->cpu_die(cpu);
628 }
629 
630 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
631 
632 void cpu_hotplug_driver_lock()
633 {
634 	mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
635 }
636 
637 void cpu_hotplug_driver_unlock()
638 {
639 	mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
640 }
641 
642 void cpu_die(void)
643 {
644 	if (ppc_md.cpu_die)
645 		ppc_md.cpu_die();
646 }
647 #endif
648