xref: /openbmc/linux/arch/powerpc/kernel/smp.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b) 
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 int smp_hw_index[NR_CPUS];
61 struct thread_info *secondary_ti;
62 
63 cpumask_t cpu_possible_map = CPU_MASK_NONE;
64 cpumask_t cpu_online_map = CPU_MASK_NONE;
65 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
66 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;
67 
68 EXPORT_SYMBOL(cpu_online_map);
69 EXPORT_SYMBOL(cpu_possible_map);
70 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
71 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
72 
73 /* SMP operations for this machine */
74 struct smp_ops_t *smp_ops;
75 
76 static volatile unsigned int cpu_callin_map[NR_CPUS];
77 
78 int smt_enabled_at_boot = 1;
79 
80 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
81 
82 #ifdef CONFIG_PPC64
83 void __devinit smp_generic_kick_cpu(int nr)
84 {
85 	BUG_ON(nr < 0 || nr >= NR_CPUS);
86 
87 	/*
88 	 * The processor is currently spinning, waiting for the
89 	 * cpu_start field to become non-zero After we set cpu_start,
90 	 * the processor will continue on to secondary_start
91 	 */
92 	paca[nr].cpu_start = 1;
93 	smp_mb();
94 }
95 #endif
96 
97 void smp_message_recv(int msg)
98 {
99 	switch(msg) {
100 	case PPC_MSG_CALL_FUNCTION:
101 		generic_smp_call_function_interrupt();
102 		break;
103 	case PPC_MSG_RESCHEDULE:
104 		/* we notice need_resched on exit */
105 		break;
106 	case PPC_MSG_CALL_FUNC_SINGLE:
107 		generic_smp_call_function_single_interrupt();
108 		break;
109 	case PPC_MSG_DEBUGGER_BREAK:
110 		if (crash_ipi_function_ptr) {
111 			crash_ipi_function_ptr(get_irq_regs());
112 			break;
113 		}
114 #ifdef CONFIG_DEBUGGER
115 		debugger_ipi(get_irq_regs());
116 		break;
117 #endif /* CONFIG_DEBUGGER */
118 		/* FALLTHROUGH */
119 	default:
120 		printk("SMP %d: smp_message_recv(): unknown msg %d\n",
121 		       smp_processor_id(), msg);
122 		break;
123 	}
124 }
125 
126 void smp_send_reschedule(int cpu)
127 {
128 	if (likely(smp_ops))
129 		smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
130 }
131 
132 void arch_send_call_function_single_ipi(int cpu)
133 {
134 	smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
135 }
136 
137 void arch_send_call_function_ipi(cpumask_t mask)
138 {
139 	unsigned int cpu;
140 
141 	for_each_cpu_mask(cpu, mask)
142 		smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
143 }
144 
145 #ifdef CONFIG_DEBUGGER
146 void smp_send_debugger_break(int cpu)
147 {
148 	if (likely(smp_ops))
149 		smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
150 }
151 #endif
152 
153 #ifdef CONFIG_KEXEC
154 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
155 {
156 	crash_ipi_function_ptr = crash_ipi_callback;
157 	if (crash_ipi_callback && smp_ops) {
158 		mb();
159 		smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
160 	}
161 }
162 #endif
163 
164 static void stop_this_cpu(void *dummy)
165 {
166 	local_irq_disable();
167 	while (1)
168 		;
169 }
170 
171 void smp_send_stop(void)
172 {
173 	smp_call_function(stop_this_cpu, NULL, 0);
174 }
175 
176 struct thread_info *current_set[NR_CPUS];
177 
178 static void __devinit smp_store_cpu_info(int id)
179 {
180 	per_cpu(pvr, id) = mfspr(SPRN_PVR);
181 }
182 
183 static void __init smp_create_idle(unsigned int cpu)
184 {
185 	struct task_struct *p;
186 
187 	/* create a process for the processor */
188 	p = fork_idle(cpu);
189 	if (IS_ERR(p))
190 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
191 #ifdef CONFIG_PPC64
192 	paca[cpu].__current = p;
193 	paca[cpu].kstack = (unsigned long) task_thread_info(p)
194 		+ THREAD_SIZE - STACK_FRAME_OVERHEAD;
195 #endif
196 	current_set[cpu] = task_thread_info(p);
197 	task_thread_info(p)->cpu = cpu;
198 }
199 
200 void __init smp_prepare_cpus(unsigned int max_cpus)
201 {
202 	unsigned int cpu;
203 
204 	DBG("smp_prepare_cpus\n");
205 
206 	/*
207 	 * setup_cpu may need to be called on the boot cpu. We havent
208 	 * spun any cpus up but lets be paranoid.
209 	 */
210 	BUG_ON(boot_cpuid != smp_processor_id());
211 
212 	/* Fixup boot cpu */
213 	smp_store_cpu_info(boot_cpuid);
214 	cpu_callin_map[boot_cpuid] = 1;
215 
216 	if (smp_ops)
217 		max_cpus = smp_ops->probe();
218 	else
219 		max_cpus = 1;
220 
221 	smp_space_timers(max_cpus);
222 
223 	for_each_possible_cpu(cpu)
224 		if (cpu != boot_cpuid)
225 			smp_create_idle(cpu);
226 }
227 
228 void __devinit smp_prepare_boot_cpu(void)
229 {
230 	BUG_ON(smp_processor_id() != boot_cpuid);
231 
232 	cpu_set(boot_cpuid, cpu_online_map);
233 	cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
234 	cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
235 #ifdef CONFIG_PPC64
236 	paca[boot_cpuid].__current = current;
237 #endif
238 	current_set[boot_cpuid] = task_thread_info(current);
239 }
240 
241 #ifdef CONFIG_HOTPLUG_CPU
242 /* State of each CPU during hotplug phases */
243 DEFINE_PER_CPU(int, cpu_state) = { 0 };
244 
245 int generic_cpu_disable(void)
246 {
247 	unsigned int cpu = smp_processor_id();
248 
249 	if (cpu == boot_cpuid)
250 		return -EBUSY;
251 
252 	cpu_clear(cpu, cpu_online_map);
253 #ifdef CONFIG_PPC64
254 	vdso_data->processorCount--;
255 	fixup_irqs(cpu_online_map);
256 #endif
257 	return 0;
258 }
259 
260 int generic_cpu_enable(unsigned int cpu)
261 {
262 	/* Do the normal bootup if we haven't
263 	 * already bootstrapped. */
264 	if (system_state != SYSTEM_RUNNING)
265 		return -ENOSYS;
266 
267 	/* get the target out of it's holding state */
268 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
269 	smp_wmb();
270 
271 	while (!cpu_online(cpu))
272 		cpu_relax();
273 
274 #ifdef CONFIG_PPC64
275 	fixup_irqs(cpu_online_map);
276 	/* counter the irq disable in fixup_irqs */
277 	local_irq_enable();
278 #endif
279 	return 0;
280 }
281 
282 void generic_cpu_die(unsigned int cpu)
283 {
284 	int i;
285 
286 	for (i = 0; i < 100; i++) {
287 		smp_rmb();
288 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
289 			return;
290 		msleep(100);
291 	}
292 	printk(KERN_ERR "CPU%d didn't die...\n", cpu);
293 }
294 
295 void generic_mach_cpu_die(void)
296 {
297 	unsigned int cpu;
298 
299 	local_irq_disable();
300 	cpu = smp_processor_id();
301 	printk(KERN_DEBUG "CPU%d offline\n", cpu);
302 	__get_cpu_var(cpu_state) = CPU_DEAD;
303 	smp_wmb();
304 	while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
305 		cpu_relax();
306 	cpu_set(cpu, cpu_online_map);
307 	local_irq_enable();
308 }
309 #endif
310 
311 static int __devinit cpu_enable(unsigned int cpu)
312 {
313 	if (smp_ops && smp_ops->cpu_enable)
314 		return smp_ops->cpu_enable(cpu);
315 
316 	return -ENOSYS;
317 }
318 
319 int __cpuinit __cpu_up(unsigned int cpu)
320 {
321 	int c;
322 
323 	secondary_ti = current_set[cpu];
324 	if (!cpu_enable(cpu))
325 		return 0;
326 
327 	if (smp_ops == NULL ||
328 	    (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
329 		return -EINVAL;
330 
331 	/* Make sure callin-map entry is 0 (can be leftover a CPU
332 	 * hotplug
333 	 */
334 	cpu_callin_map[cpu] = 0;
335 
336 	/* The information for processor bringup must
337 	 * be written out to main store before we release
338 	 * the processor.
339 	 */
340 	smp_mb();
341 
342 	/* wake up cpus */
343 	DBG("smp: kicking cpu %d\n", cpu);
344 	smp_ops->kick_cpu(cpu);
345 
346 	/*
347 	 * wait to see if the cpu made a callin (is actually up).
348 	 * use this value that I found through experimentation.
349 	 * -- Cort
350 	 */
351 	if (system_state < SYSTEM_RUNNING)
352 		for (c = 50000; c && !cpu_callin_map[cpu]; c--)
353 			udelay(100);
354 #ifdef CONFIG_HOTPLUG_CPU
355 	else
356 		/*
357 		 * CPUs can take much longer to come up in the
358 		 * hotplug case.  Wait five seconds.
359 		 */
360 		for (c = 25; c && !cpu_callin_map[cpu]; c--) {
361 			msleep(200);
362 		}
363 #endif
364 
365 	if (!cpu_callin_map[cpu]) {
366 		printk("Processor %u is stuck.\n", cpu);
367 		return -ENOENT;
368 	}
369 
370 	printk("Processor %u found.\n", cpu);
371 
372 	if (smp_ops->give_timebase)
373 		smp_ops->give_timebase();
374 
375 	/* Wait until cpu puts itself in the online map */
376 	while (!cpu_online(cpu))
377 		cpu_relax();
378 
379 	return 0;
380 }
381 
382 /* Return the value of the reg property corresponding to the given
383  * logical cpu.
384  */
385 int cpu_to_core_id(int cpu)
386 {
387 	struct device_node *np;
388 	const int *reg;
389 	int id = -1;
390 
391 	np = of_get_cpu_node(cpu, NULL);
392 	if (!np)
393 		goto out;
394 
395 	reg = of_get_property(np, "reg", NULL);
396 	if (!reg)
397 		goto out;
398 
399 	id = *reg;
400 out:
401 	of_node_put(np);
402 	return id;
403 }
404 
405 /* Must be called when no change can occur to cpu_present_map,
406  * i.e. during cpu online or offline.
407  */
408 static struct device_node *cpu_to_l2cache(int cpu)
409 {
410 	struct device_node *np;
411 	const phandle *php;
412 	phandle ph;
413 
414 	if (!cpu_present(cpu))
415 		return NULL;
416 
417 	np = of_get_cpu_node(cpu, NULL);
418 	if (np == NULL)
419 		return NULL;
420 
421 	php = of_get_property(np, "l2-cache", NULL);
422 	if (php == NULL)
423 		return NULL;
424 	ph = *php;
425 	of_node_put(np);
426 
427 	return of_find_node_by_phandle(ph);
428 }
429 
430 /* Activate a secondary processor. */
431 int __devinit start_secondary(void *unused)
432 {
433 	unsigned int cpu = smp_processor_id();
434 	struct device_node *l2_cache;
435 	int i, base;
436 
437 	atomic_inc(&init_mm.mm_count);
438 	current->active_mm = &init_mm;
439 
440 	smp_store_cpu_info(cpu);
441 	set_dec(tb_ticks_per_jiffy);
442 	preempt_disable();
443 	cpu_callin_map[cpu] = 1;
444 
445 	smp_ops->setup_cpu(cpu);
446 	if (smp_ops->take_timebase)
447 		smp_ops->take_timebase();
448 
449 	if (system_state > SYSTEM_BOOTING)
450 		snapshot_timebase();
451 
452 	secondary_cpu_time_init();
453 
454 	ipi_call_lock();
455 	notify_cpu_starting(cpu);
456 	cpu_set(cpu, cpu_online_map);
457 	/* Update sibling maps */
458 	base = cpu_first_thread_in_core(cpu);
459 	for (i = 0; i < threads_per_core; i++) {
460 		if (cpu_is_offline(base + i))
461 			continue;
462 		cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
463 		cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
464 
465 		/* cpu_core_map should be a superset of
466 		 * cpu_sibling_map even if we don't have cache
467 		 * information, so update the former here, too.
468 		 */
469 		cpu_set(cpu, per_cpu(cpu_core_map, base +i));
470 		cpu_set(base + i, per_cpu(cpu_core_map, cpu));
471 	}
472 	l2_cache = cpu_to_l2cache(cpu);
473 	for_each_online_cpu(i) {
474 		struct device_node *np = cpu_to_l2cache(i);
475 		if (!np)
476 			continue;
477 		if (np == l2_cache) {
478 			cpu_set(cpu, per_cpu(cpu_core_map, i));
479 			cpu_set(i, per_cpu(cpu_core_map, cpu));
480 		}
481 		of_node_put(np);
482 	}
483 	of_node_put(l2_cache);
484 	ipi_call_unlock();
485 
486 	local_irq_enable();
487 
488 	cpu_idle();
489 	return 0;
490 }
491 
492 int setup_profiling_timer(unsigned int multiplier)
493 {
494 	return 0;
495 }
496 
497 void __init smp_cpus_done(unsigned int max_cpus)
498 {
499 	cpumask_t old_mask;
500 
501 	/* We want the setup_cpu() here to be called from CPU 0, but our
502 	 * init thread may have been "borrowed" by another CPU in the meantime
503 	 * se we pin us down to CPU 0 for a short while
504 	 */
505 	old_mask = current->cpus_allowed;
506 	set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
507 
508 	if (smp_ops)
509 		smp_ops->setup_cpu(boot_cpuid);
510 
511 	set_cpus_allowed(current, old_mask);
512 
513 	snapshot_timebases();
514 
515 	dump_numa_cpu_topology();
516 }
517 
518 #ifdef CONFIG_HOTPLUG_CPU
519 int __cpu_disable(void)
520 {
521 	struct device_node *l2_cache;
522 	int cpu = smp_processor_id();
523 	int base, i;
524 	int err;
525 
526 	if (!smp_ops->cpu_disable)
527 		return -ENOSYS;
528 
529 	err = smp_ops->cpu_disable();
530 	if (err)
531 		return err;
532 
533 	/* Update sibling maps */
534 	base = cpu_first_thread_in_core(cpu);
535 	for (i = 0; i < threads_per_core; i++) {
536 		cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
537 		cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
538 		cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
539 		cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
540 	}
541 
542 	l2_cache = cpu_to_l2cache(cpu);
543 	for_each_present_cpu(i) {
544 		struct device_node *np = cpu_to_l2cache(i);
545 		if (!np)
546 			continue;
547 		if (np == l2_cache) {
548 			cpu_clear(cpu, per_cpu(cpu_core_map, i));
549 			cpu_clear(i, per_cpu(cpu_core_map, cpu));
550 		}
551 		of_node_put(np);
552 	}
553 	of_node_put(l2_cache);
554 
555 
556 	return 0;
557 }
558 
559 void __cpu_die(unsigned int cpu)
560 {
561 	if (smp_ops->cpu_die)
562 		smp_ops->cpu_die(cpu);
563 }
564 #endif
565