xref: /openbmc/linux/arch/powerpc/kernel/smp.c (revision 98a79d6a50181ca1ecf7400eda01d5dc1bc0dbf0) 
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 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
64 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;
65 
66 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
67 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
68 
69 /* SMP operations for this machine */
70 struct smp_ops_t *smp_ops;
71 
72 static 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 void smp_send_reschedule(int cpu)
123 {
124 	if (likely(smp_ops))
125 		smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
126 }
127 
128 void arch_send_call_function_single_ipi(int cpu)
129 {
130 	smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
131 }
132 
133 void arch_send_call_function_ipi(cpumask_t mask)
134 {
135 	unsigned int cpu;
136 
137 	for_each_cpu_mask(cpu, mask)
138 		smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
139 }
140 
141 #ifdef CONFIG_DEBUGGER
142 void smp_send_debugger_break(int cpu)
143 {
144 	if (likely(smp_ops))
145 		smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
146 }
147 #endif
148 
149 #ifdef CONFIG_KEXEC
150 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
151 {
152 	crash_ipi_function_ptr = crash_ipi_callback;
153 	if (crash_ipi_callback && smp_ops) {
154 		mb();
155 		smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
156 	}
157 }
158 #endif
159 
160 static void stop_this_cpu(void *dummy)
161 {
162 	local_irq_disable();
163 	while (1)
164 		;
165 }
166 
167 void smp_send_stop(void)
168 {
169 	smp_call_function(stop_this_cpu, NULL, 0);
170 }
171 
172 struct thread_info *current_set[NR_CPUS];
173 
174 static void __devinit smp_store_cpu_info(int id)
175 {
176 	per_cpu(pvr, id) = mfspr(SPRN_PVR);
177 }
178 
179 static void __init smp_create_idle(unsigned int cpu)
180 {
181 	struct task_struct *p;
182 
183 	/* create a process for the processor */
184 	p = fork_idle(cpu);
185 	if (IS_ERR(p))
186 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
187 #ifdef CONFIG_PPC64
188 	paca[cpu].__current = p;
189 	paca[cpu].kstack = (unsigned long) task_thread_info(p)
190 		+ THREAD_SIZE - STACK_FRAME_OVERHEAD;
191 #endif
192 	current_set[cpu] = task_thread_info(p);
193 	task_thread_info(p)->cpu = cpu;
194 }
195 
196 void __init smp_prepare_cpus(unsigned int max_cpus)
197 {
198 	unsigned int cpu;
199 
200 	DBG("smp_prepare_cpus\n");
201 
202 	/*
203 	 * setup_cpu may need to be called on the boot cpu. We havent
204 	 * spun any cpus up but lets be paranoid.
205 	 */
206 	BUG_ON(boot_cpuid != smp_processor_id());
207 
208 	/* Fixup boot cpu */
209 	smp_store_cpu_info(boot_cpuid);
210 	cpu_callin_map[boot_cpuid] = 1;
211 
212 	if (smp_ops)
213 		max_cpus = smp_ops->probe();
214 	else
215 		max_cpus = 1;
216 
217 	smp_space_timers(max_cpus);
218 
219 	for_each_possible_cpu(cpu)
220 		if (cpu != boot_cpuid)
221 			smp_create_idle(cpu);
222 }
223 
224 void __devinit smp_prepare_boot_cpu(void)
225 {
226 	BUG_ON(smp_processor_id() != boot_cpuid);
227 
228 	cpu_set(boot_cpuid, cpu_online_map);
229 	cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
230 	cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
231 #ifdef CONFIG_PPC64
232 	paca[boot_cpuid].__current = current;
233 #endif
234 	current_set[boot_cpuid] = task_thread_info(current);
235 }
236 
237 #ifdef CONFIG_HOTPLUG_CPU
238 /* State of each CPU during hotplug phases */
239 DEFINE_PER_CPU(int, cpu_state) = { 0 };
240 
241 int generic_cpu_disable(void)
242 {
243 	unsigned int cpu = smp_processor_id();
244 
245 	if (cpu == boot_cpuid)
246 		return -EBUSY;
247 
248 	cpu_clear(cpu, cpu_online_map);
249 #ifdef CONFIG_PPC64
250 	vdso_data->processorCount--;
251 	fixup_irqs(cpu_online_map);
252 #endif
253 	return 0;
254 }
255 
256 int generic_cpu_enable(unsigned int cpu)
257 {
258 	/* Do the normal bootup if we haven't
259 	 * already bootstrapped. */
260 	if (system_state != SYSTEM_RUNNING)
261 		return -ENOSYS;
262 
263 	/* get the target out of it's holding state */
264 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
265 	smp_wmb();
266 
267 	while (!cpu_online(cpu))
268 		cpu_relax();
269 
270 #ifdef CONFIG_PPC64
271 	fixup_irqs(cpu_online_map);
272 	/* counter the irq disable in fixup_irqs */
273 	local_irq_enable();
274 #endif
275 	return 0;
276 }
277 
278 void generic_cpu_die(unsigned int cpu)
279 {
280 	int i;
281 
282 	for (i = 0; i < 100; i++) {
283 		smp_rmb();
284 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
285 			return;
286 		msleep(100);
287 	}
288 	printk(KERN_ERR "CPU%d didn't die...\n", cpu);
289 }
290 
291 void generic_mach_cpu_die(void)
292 {
293 	unsigned int cpu;
294 
295 	local_irq_disable();
296 	cpu = smp_processor_id();
297 	printk(KERN_DEBUG "CPU%d offline\n", cpu);
298 	__get_cpu_var(cpu_state) = CPU_DEAD;
299 	smp_wmb();
300 	while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
301 		cpu_relax();
302 	cpu_set(cpu, cpu_online_map);
303 	local_irq_enable();
304 }
305 #endif
306 
307 static int __devinit cpu_enable(unsigned int cpu)
308 {
309 	if (smp_ops && smp_ops->cpu_enable)
310 		return smp_ops->cpu_enable(cpu);
311 
312 	return -ENOSYS;
313 }
314 
315 int __cpuinit __cpu_up(unsigned int cpu)
316 {
317 	int c;
318 
319 	secondary_ti = current_set[cpu];
320 	if (!cpu_enable(cpu))
321 		return 0;
322 
323 	if (smp_ops == NULL ||
324 	    (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
325 		return -EINVAL;
326 
327 	/* Make sure callin-map entry is 0 (can be leftover a CPU
328 	 * hotplug
329 	 */
330 	cpu_callin_map[cpu] = 0;
331 
332 	/* The information for processor bringup must
333 	 * be written out to main store before we release
334 	 * the processor.
335 	 */
336 	smp_mb();
337 
338 	/* wake up cpus */
339 	DBG("smp: kicking cpu %d\n", cpu);
340 	smp_ops->kick_cpu(cpu);
341 
342 	/*
343 	 * wait to see if the cpu made a callin (is actually up).
344 	 * use this value that I found through experimentation.
345 	 * -- Cort
346 	 */
347 	if (system_state < SYSTEM_RUNNING)
348 		for (c = 50000; c && !cpu_callin_map[cpu]; c--)
349 			udelay(100);
350 #ifdef CONFIG_HOTPLUG_CPU
351 	else
352 		/*
353 		 * CPUs can take much longer to come up in the
354 		 * hotplug case.  Wait five seconds.
355 		 */
356 		for (c = 25; c && !cpu_callin_map[cpu]; c--) {
357 			msleep(200);
358 		}
359 #endif
360 
361 	if (!cpu_callin_map[cpu]) {
362 		printk("Processor %u is stuck.\n", cpu);
363 		return -ENOENT;
364 	}
365 
366 	printk("Processor %u found.\n", cpu);
367 
368 	if (smp_ops->give_timebase)
369 		smp_ops->give_timebase();
370 
371 	/* Wait until cpu puts itself in the online map */
372 	while (!cpu_online(cpu))
373 		cpu_relax();
374 
375 	return 0;
376 }
377 
378 /* Return the value of the reg property corresponding to the given
379  * logical cpu.
380  */
381 int cpu_to_core_id(int cpu)
382 {
383 	struct device_node *np;
384 	const int *reg;
385 	int id = -1;
386 
387 	np = of_get_cpu_node(cpu, NULL);
388 	if (!np)
389 		goto out;
390 
391 	reg = of_get_property(np, "reg", NULL);
392 	if (!reg)
393 		goto out;
394 
395 	id = *reg;
396 out:
397 	of_node_put(np);
398 	return id;
399 }
400 
401 /* Must be called when no change can occur to cpu_present_map,
402  * i.e. during cpu online or offline.
403  */
404 static struct device_node *cpu_to_l2cache(int cpu)
405 {
406 	struct device_node *np;
407 	const phandle *php;
408 	phandle ph;
409 
410 	if (!cpu_present(cpu))
411 		return NULL;
412 
413 	np = of_get_cpu_node(cpu, NULL);
414 	if (np == NULL)
415 		return NULL;
416 
417 	php = of_get_property(np, "l2-cache", NULL);
418 	if (php == NULL)
419 		return NULL;
420 	ph = *php;
421 	of_node_put(np);
422 
423 	return of_find_node_by_phandle(ph);
424 }
425 
426 /* Activate a secondary processor. */
427 int __devinit start_secondary(void *unused)
428 {
429 	unsigned int cpu = smp_processor_id();
430 	struct device_node *l2_cache;
431 	int i, base;
432 
433 	atomic_inc(&init_mm.mm_count);
434 	current->active_mm = &init_mm;
435 
436 	smp_store_cpu_info(cpu);
437 	set_dec(tb_ticks_per_jiffy);
438 	preempt_disable();
439 	cpu_callin_map[cpu] = 1;
440 
441 	smp_ops->setup_cpu(cpu);
442 	if (smp_ops->take_timebase)
443 		smp_ops->take_timebase();
444 
445 	if (system_state > SYSTEM_BOOTING)
446 		snapshot_timebase();
447 
448 	secondary_cpu_time_init();
449 
450 	ipi_call_lock();
451 	notify_cpu_starting(cpu);
452 	cpu_set(cpu, cpu_online_map);
453 	/* Update sibling maps */
454 	base = cpu_first_thread_in_core(cpu);
455 	for (i = 0; i < threads_per_core; i++) {
456 		if (cpu_is_offline(base + i))
457 			continue;
458 		cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
459 		cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
460 
461 		/* cpu_core_map should be a superset of
462 		 * cpu_sibling_map even if we don't have cache
463 		 * information, so update the former here, too.
464 		 */
465 		cpu_set(cpu, per_cpu(cpu_core_map, base +i));
466 		cpu_set(base + i, per_cpu(cpu_core_map, cpu));
467 	}
468 	l2_cache = cpu_to_l2cache(cpu);
469 	for_each_online_cpu(i) {
470 		struct device_node *np = cpu_to_l2cache(i);
471 		if (!np)
472 			continue;
473 		if (np == l2_cache) {
474 			cpu_set(cpu, per_cpu(cpu_core_map, i));
475 			cpu_set(i, per_cpu(cpu_core_map, cpu));
476 		}
477 		of_node_put(np);
478 	}
479 	of_node_put(l2_cache);
480 	ipi_call_unlock();
481 
482 	local_irq_enable();
483 
484 	cpu_idle();
485 	return 0;
486 }
487 
488 int setup_profiling_timer(unsigned int multiplier)
489 {
490 	return 0;
491 }
492 
493 void __init smp_cpus_done(unsigned int max_cpus)
494 {
495 	cpumask_t old_mask;
496 
497 	/* We want the setup_cpu() here to be called from CPU 0, but our
498 	 * init thread may have been "borrowed" by another CPU in the meantime
499 	 * se we pin us down to CPU 0 for a short while
500 	 */
501 	old_mask = current->cpus_allowed;
502 	set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
503 
504 	if (smp_ops)
505 		smp_ops->setup_cpu(boot_cpuid);
506 
507 	set_cpus_allowed(current, old_mask);
508 
509 	snapshot_timebases();
510 
511 	dump_numa_cpu_topology();
512 }
513 
514 #ifdef CONFIG_HOTPLUG_CPU
515 int __cpu_disable(void)
516 {
517 	struct device_node *l2_cache;
518 	int cpu = smp_processor_id();
519 	int base, i;
520 	int err;
521 
522 	if (!smp_ops->cpu_disable)
523 		return -ENOSYS;
524 
525 	err = smp_ops->cpu_disable();
526 	if (err)
527 		return err;
528 
529 	/* Update sibling maps */
530 	base = cpu_first_thread_in_core(cpu);
531 	for (i = 0; i < threads_per_core; i++) {
532 		cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
533 		cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
534 		cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
535 		cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
536 	}
537 
538 	l2_cache = cpu_to_l2cache(cpu);
539 	for_each_present_cpu(i) {
540 		struct device_node *np = cpu_to_l2cache(i);
541 		if (!np)
542 			continue;
543 		if (np == l2_cache) {
544 			cpu_clear(cpu, per_cpu(cpu_core_map, i));
545 			cpu_clear(i, per_cpu(cpu_core_map, cpu));
546 		}
547 		of_node_put(np);
548 	}
549 	of_node_put(l2_cache);
550 
551 
552 	return 0;
553 }
554 
555 void __cpu_die(unsigned int cpu)
556 {
557 	if (smp_ops->cpu_die)
558 		smp_ops->cpu_die(cpu);
559 }
560 #endif
561