xref: /openbmc/linux/arch/powerpc/kernel/smp.c (revision f15cbe6f1a4b4d9df59142fc8e4abb973302cf44) 
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 		/* XXX Do we have to do this? */
105 		set_need_resched();
106 		break;
107 	case PPC_MSG_CALL_FUNC_SINGLE:
108 		generic_smp_call_function_single_interrupt();
109 		break;
110 	case PPC_MSG_DEBUGGER_BREAK:
111 		if (crash_ipi_function_ptr) {
112 			crash_ipi_function_ptr(get_irq_regs());
113 			break;
114 		}
115 #ifdef CONFIG_DEBUGGER
116 		debugger_ipi(get_irq_regs());
117 		break;
118 #endif /* CONFIG_DEBUGGER */
119 		/* FALLTHROUGH */
120 	default:
121 		printk("SMP %d: smp_message_recv(): unknown msg %d\n",
122 		       smp_processor_id(), msg);
123 		break;
124 	}
125 }
126 
127 void smp_send_reschedule(int cpu)
128 {
129 	if (likely(smp_ops))
130 		smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
131 }
132 
133 void arch_send_call_function_single_ipi(int cpu)
134 {
135 	smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
136 }
137 
138 void arch_send_call_function_ipi(cpumask_t mask)
139 {
140 	unsigned int cpu;
141 
142 	for_each_cpu_mask(cpu, mask)
143 		smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
144 }
145 
146 #ifdef CONFIG_DEBUGGER
147 void smp_send_debugger_break(int cpu)
148 {
149 	if (likely(smp_ops))
150 		smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
151 }
152 #endif
153 
154 #ifdef CONFIG_KEXEC
155 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
156 {
157 	crash_ipi_function_ptr = crash_ipi_callback;
158 	if (crash_ipi_callback && smp_ops) {
159 		mb();
160 		smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
161 	}
162 }
163 #endif
164 
165 static void stop_this_cpu(void *dummy)
166 {
167 	local_irq_disable();
168 	while (1)
169 		;
170 }
171 
172 void smp_send_stop(void)
173 {
174 	smp_call_function(stop_this_cpu, NULL, 0);
175 }
176 
177 struct thread_info *current_set[NR_CPUS];
178 
179 static void __devinit smp_store_cpu_info(int id)
180 {
181 	per_cpu(pvr, id) = mfspr(SPRN_PVR);
182 }
183 
184 static void __init smp_create_idle(unsigned int cpu)
185 {
186 	struct task_struct *p;
187 
188 	/* create a process for the processor */
189 	p = fork_idle(cpu);
190 	if (IS_ERR(p))
191 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
192 #ifdef CONFIG_PPC64
193 	paca[cpu].__current = p;
194 	paca[cpu].kstack = (unsigned long) task_thread_info(p)
195 		+ THREAD_SIZE - STACK_FRAME_OVERHEAD;
196 #endif
197 	current_set[cpu] = task_thread_info(p);
198 	task_thread_info(p)->cpu = cpu;
199 }
200 
201 void __init smp_prepare_cpus(unsigned int max_cpus)
202 {
203 	unsigned int cpu;
204 
205 	DBG("smp_prepare_cpus\n");
206 
207 	/*
208 	 * setup_cpu may need to be called on the boot cpu. We havent
209 	 * spun any cpus up but lets be paranoid.
210 	 */
211 	BUG_ON(boot_cpuid != smp_processor_id());
212 
213 	/* Fixup boot cpu */
214 	smp_store_cpu_info(boot_cpuid);
215 	cpu_callin_map[boot_cpuid] = 1;
216 
217 	if (smp_ops)
218 		max_cpus = smp_ops->probe();
219 	else
220 		max_cpus = 1;
221 
222 	smp_space_timers(max_cpus);
223 
224 	for_each_possible_cpu(cpu)
225 		if (cpu != boot_cpuid)
226 			smp_create_idle(cpu);
227 }
228 
229 void __devinit smp_prepare_boot_cpu(void)
230 {
231 	BUG_ON(smp_processor_id() != boot_cpuid);
232 
233 	cpu_set(boot_cpuid, cpu_online_map);
234 	cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
235 	cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
236 #ifdef CONFIG_PPC64
237 	paca[boot_cpuid].__current = current;
238 #endif
239 	current_set[boot_cpuid] = task_thread_info(current);
240 }
241 
242 #ifdef CONFIG_HOTPLUG_CPU
243 /* State of each CPU during hotplug phases */
244 DEFINE_PER_CPU(int, cpu_state) = { 0 };
245 
246 int generic_cpu_disable(void)
247 {
248 	unsigned int cpu = smp_processor_id();
249 
250 	if (cpu == boot_cpuid)
251 		return -EBUSY;
252 
253 	cpu_clear(cpu, cpu_online_map);
254 #ifdef CONFIG_PPC64
255 	vdso_data->processorCount--;
256 	fixup_irqs(cpu_online_map);
257 #endif
258 	return 0;
259 }
260 
261 int generic_cpu_enable(unsigned int cpu)
262 {
263 	/* Do the normal bootup if we haven't
264 	 * already bootstrapped. */
265 	if (system_state != SYSTEM_RUNNING)
266 		return -ENOSYS;
267 
268 	/* get the target out of it's holding state */
269 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
270 	smp_wmb();
271 
272 	while (!cpu_online(cpu))
273 		cpu_relax();
274 
275 #ifdef CONFIG_PPC64
276 	fixup_irqs(cpu_online_map);
277 	/* counter the irq disable in fixup_irqs */
278 	local_irq_enable();
279 #endif
280 	return 0;
281 }
282 
283 void generic_cpu_die(unsigned int cpu)
284 {
285 	int i;
286 
287 	for (i = 0; i < 100; i++) {
288 		smp_rmb();
289 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
290 			return;
291 		msleep(100);
292 	}
293 	printk(KERN_ERR "CPU%d didn't die...\n", cpu);
294 }
295 
296 void generic_mach_cpu_die(void)
297 {
298 	unsigned int cpu;
299 
300 	local_irq_disable();
301 	cpu = smp_processor_id();
302 	printk(KERN_DEBUG "CPU%d offline\n", cpu);
303 	__get_cpu_var(cpu_state) = CPU_DEAD;
304 	smp_wmb();
305 	while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
306 		cpu_relax();
307 	cpu_set(cpu, cpu_online_map);
308 	local_irq_enable();
309 }
310 #endif
311 
312 static int __devinit cpu_enable(unsigned int cpu)
313 {
314 	if (smp_ops && smp_ops->cpu_enable)
315 		return smp_ops->cpu_enable(cpu);
316 
317 	return -ENOSYS;
318 }
319 
320 int __cpuinit __cpu_up(unsigned int cpu)
321 {
322 	int c;
323 
324 	secondary_ti = current_set[cpu];
325 	if (!cpu_enable(cpu))
326 		return 0;
327 
328 	if (smp_ops == NULL ||
329 	    (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
330 		return -EINVAL;
331 
332 	/* Make sure callin-map entry is 0 (can be leftover a CPU
333 	 * hotplug
334 	 */
335 	cpu_callin_map[cpu] = 0;
336 
337 	/* The information for processor bringup must
338 	 * be written out to main store before we release
339 	 * the processor.
340 	 */
341 	smp_mb();
342 
343 	/* wake up cpus */
344 	DBG("smp: kicking cpu %d\n", cpu);
345 	smp_ops->kick_cpu(cpu);
346 
347 	/*
348 	 * wait to see if the cpu made a callin (is actually up).
349 	 * use this value that I found through experimentation.
350 	 * -- Cort
351 	 */
352 	if (system_state < SYSTEM_RUNNING)
353 		for (c = 50000; c && !cpu_callin_map[cpu]; c--)
354 			udelay(100);
355 #ifdef CONFIG_HOTPLUG_CPU
356 	else
357 		/*
358 		 * CPUs can take much longer to come up in the
359 		 * hotplug case.  Wait five seconds.
360 		 */
361 		for (c = 25; c && !cpu_callin_map[cpu]; c--) {
362 			msleep(200);
363 		}
364 #endif
365 
366 	if (!cpu_callin_map[cpu]) {
367 		printk("Processor %u is stuck.\n", cpu);
368 		return -ENOENT;
369 	}
370 
371 	printk("Processor %u found.\n", cpu);
372 
373 	if (smp_ops->give_timebase)
374 		smp_ops->give_timebase();
375 
376 	/* Wait until cpu puts itself in the online map */
377 	while (!cpu_online(cpu))
378 		cpu_relax();
379 
380 	return 0;
381 }
382 
383 /* Return the value of the reg property corresponding to the given
384  * logical cpu.
385  */
386 int cpu_to_core_id(int cpu)
387 {
388 	struct device_node *np;
389 	const int *reg;
390 	int id = -1;
391 
392 	np = of_get_cpu_node(cpu, NULL);
393 	if (!np)
394 		goto out;
395 
396 	reg = of_get_property(np, "reg", NULL);
397 	if (!reg)
398 		goto out;
399 
400 	id = *reg;
401 out:
402 	of_node_put(np);
403 	return id;
404 }
405 
406 /* Must be called when no change can occur to cpu_present_map,
407  * i.e. during cpu online or offline.
408  */
409 static struct device_node *cpu_to_l2cache(int cpu)
410 {
411 	struct device_node *np;
412 	const phandle *php;
413 	phandle ph;
414 
415 	if (!cpu_present(cpu))
416 		return NULL;
417 
418 	np = of_get_cpu_node(cpu, NULL);
419 	if (np == NULL)
420 		return NULL;
421 
422 	php = of_get_property(np, "l2-cache", NULL);
423 	if (php == NULL)
424 		return NULL;
425 	ph = *php;
426 	of_node_put(np);
427 
428 	return of_find_node_by_phandle(ph);
429 }
430 
431 /* Activate a secondary processor. */
432 int __devinit start_secondary(void *unused)
433 {
434 	unsigned int cpu = smp_processor_id();
435 	struct device_node *l2_cache;
436 	int i, base;
437 
438 	atomic_inc(&init_mm.mm_count);
439 	current->active_mm = &init_mm;
440 
441 	smp_store_cpu_info(cpu);
442 	set_dec(tb_ticks_per_jiffy);
443 	preempt_disable();
444 	cpu_callin_map[cpu] = 1;
445 
446 	smp_ops->setup_cpu(cpu);
447 	if (smp_ops->take_timebase)
448 		smp_ops->take_timebase();
449 
450 	if (system_state > SYSTEM_BOOTING)
451 		snapshot_timebase();
452 
453 	secondary_cpu_time_init();
454 
455 	ipi_call_lock();
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