Branch data Line data Source code
1 : : /*
2 : : * Generic helpers for smp ipi calls
3 : : *
4 : : * (C) Jens Axboe <jens.axboe@oracle.com> 2008
5 : : */
6 : : #include <linux/rcupdate.h>
7 : : #include <linux/rculist.h>
8 : : #include <linux/kernel.h>
9 : : #include <linux/export.h>
10 : : #include <linux/percpu.h>
11 : : #include <linux/init.h>
12 : : #include <linux/gfp.h>
13 : : #include <linux/smp.h>
14 : : #include <linux/cpu.h>
15 : :
16 : : #include "smpboot.h"
17 : :
18 : : enum {
19 : : CSD_FLAG_LOCK = 0x01,
20 : : CSD_FLAG_WAIT = 0x02,
21 : : };
22 : :
23 : : struct call_function_data {
24 : : struct call_single_data __percpu *csd;
25 : : cpumask_var_t cpumask;
26 : : cpumask_var_t cpumask_ipi;
27 : : };
28 : :
29 : : static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data);
30 : :
31 : : struct call_single_queue {
32 : : struct list_head list;
33 : : raw_spinlock_t lock;
34 : : };
35 : :
36 : : static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_queue, call_single_queue);
37 : :
38 : : static int
39 : 0 : hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
40 : : {
41 : 0 : long cpu = (long)hcpu;
42 [ # # ][ # # ]: 0 : struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
[ # # ]
43 : :
44 : : switch (action) {
45 : : case CPU_UP_PREPARE:
46 : : case CPU_UP_PREPARE_FROZEN:
47 : : if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
48 : : cpu_to_node(cpu)))
49 : : return notifier_from_errno(-ENOMEM);
50 : : if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL,
51 : : cpu_to_node(cpu))) {
52 : : free_cpumask_var(cfd->cpumask);
53 : : return notifier_from_errno(-ENOMEM);
54 : : }
55 : 0 : cfd->csd = alloc_percpu(struct call_single_data);
56 [ # # ]: 0 : if (!cfd->csd) {
57 : : free_cpumask_var(cfd->cpumask_ipi);
58 : : free_cpumask_var(cfd->cpumask);
59 : : return notifier_from_errno(-ENOMEM);
60 : : }
61 : : break;
62 : :
63 : : #ifdef CONFIG_HOTPLUG_CPU
64 : : case CPU_UP_CANCELED:
65 : : case CPU_UP_CANCELED_FROZEN:
66 : :
67 : : case CPU_DEAD:
68 : : case CPU_DEAD_FROZEN:
69 : : free_cpumask_var(cfd->cpumask);
70 : : free_cpumask_var(cfd->cpumask_ipi);
71 : 0 : free_percpu(cfd->csd);
72 : 0 : break;
73 : : #endif
74 : : };
75 : :
76 : : return NOTIFY_OK;
77 : : }
78 : :
79 : : static struct notifier_block hotplug_cfd_notifier = {
80 : : .notifier_call = hotplug_cfd,
81 : : };
82 : :
83 : 0 : void __init call_function_init(void)
84 : : {
85 : 0 : void *cpu = (void *)(long)smp_processor_id();
86 : : int i;
87 : :
88 [ # # ]: 0 : for_each_possible_cpu(i) {
89 : 0 : struct call_single_queue *q = &per_cpu(call_single_queue, i);
90 : :
91 : 0 : raw_spin_lock_init(&q->lock);
92 : 0 : INIT_LIST_HEAD(&q->list);
93 : : }
94 : :
95 : 0 : hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu);
96 : 0 : register_cpu_notifier(&hotplug_cfd_notifier);
97 : 0 : }
98 : :
99 : : /*
100 : : * csd_lock/csd_unlock used to serialize access to per-cpu csd resources
101 : : *
102 : : * For non-synchronous ipi calls the csd can still be in use by the
103 : : * previous function call. For multi-cpu calls its even more interesting
104 : : * as we'll have to ensure no other cpu is observing our csd.
105 : : */
106 : : static void csd_lock_wait(struct call_single_data *csd)
107 : : {
108 [ # # ][ # # ]: 2057752 : while (csd->flags & CSD_FLAG_LOCK)
[ # # ][ - + ]
[ + + ]
109 : 2057508 : cpu_relax();
110 : : }
111 : :
112 : : static void csd_lock(struct call_single_data *csd)
113 : : {
114 : : csd_lock_wait(csd);
115 : 122 : csd->flags |= CSD_FLAG_LOCK;
116 : :
117 : : /*
118 : : * prevent CPU from reordering the above assignment
119 : : * to ->flags with any subsequent assignments to other
120 : : * fields of the specified call_single_data structure:
121 : : */
122 : 122 : smp_mb();
123 : : }
124 : :
125 : 0 : static void csd_unlock(struct call_single_data *csd)
126 : : {
127 [ - + ]: 122 : WARN_ON((csd->flags & CSD_FLAG_WAIT) && !(csd->flags & CSD_FLAG_LOCK));
128 : :
129 : : /*
130 : : * ensure we're all done before releasing data:
131 : : */
132 : 122 : smp_mb();
133 : :
134 : 122 : csd->flags &= ~CSD_FLAG_LOCK;
135 : 122 : }
136 : :
137 : : /*
138 : : * Insert a previously allocated call_single_data element
139 : : * for execution on the given CPU. data must already have
140 : : * ->func, ->info, and ->flags set.
141 : : */
142 : 0 : static void generic_exec_single(int cpu, struct call_single_data *csd, int wait)
143 : : {
144 : 122 : struct call_single_queue *dst = &per_cpu(call_single_queue, cpu);
145 : : unsigned long flags;
146 : : int ipi;
147 : :
148 [ + - ]: 122 : if (wait)
149 : 122 : csd->flags |= CSD_FLAG_WAIT;
150 : :
151 : 122 : raw_spin_lock_irqsave(&dst->lock, flags);
152 : 122 : ipi = list_empty(&dst->list);
153 : 122 : list_add_tail(&csd->list, &dst->list);
154 : 122 : raw_spin_unlock_irqrestore(&dst->lock, flags);
155 : :
156 : : /*
157 : : * The list addition should be visible before sending the IPI
158 : : * handler locks the list to pull the entry off it because of
159 : : * normal cache coherency rules implied by spinlocks.
160 : : *
161 : : * If IPIs can go out of order to the cache coherency protocol
162 : : * in an architecture, sufficient synchronisation should be added
163 : : * to arch code to make it appear to obey cache coherency WRT
164 : : * locking and barrier primitives. Generic code isn't really
165 : : * equipped to do the right thing...
166 : : */
167 [ + - ]: 122 : if (ipi)
168 : 122 : arch_send_call_function_single_ipi(cpu);
169 : :
170 [ + - ]: 244 : if (wait)
171 : : csd_lock_wait(csd);
172 : 122 : }
173 : :
174 : : /*
175 : : * Invoked by arch to handle an IPI for call function single. Must be
176 : : * called from the arch with interrupts disabled.
177 : : */
178 : 0 : void generic_smp_call_function_single_interrupt(void)
179 : : {
180 : 244 : struct call_single_queue *q = &__get_cpu_var(call_single_queue);
181 : 122 : LIST_HEAD(list);
182 : :
183 : : /*
184 : : * Shouldn't receive this interrupt on a cpu that is not yet online.
185 : : */
186 [ - + ][ # # ]: 122 : WARN_ON_ONCE(!cpu_online(smp_processor_id()));
[ # # ]
187 : :
188 : 122 : raw_spin_lock(&q->lock);
189 : 122 : list_replace_init(&q->list, &list);
190 : : raw_spin_unlock(&q->lock);
191 : :
192 [ + + ]: 244 : while (!list_empty(&list)) {
193 : : struct call_single_data *csd;
194 : :
195 : : csd = list_entry(list.next, struct call_single_data, list);
196 : : list_del(&csd->list);
197 : :
198 : 122 : csd->func(csd->info);
199 : :
200 : 122 : csd_unlock(csd);
201 : : }
202 : 122 : }
203 : :
204 : : static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
205 : :
206 : : /*
207 : : * smp_call_function_single - Run a function on a specific CPU
208 : : * @func: The function to run. This must be fast and non-blocking.
209 : : * @info: An arbitrary pointer to pass to the function.
210 : : * @wait: If true, wait until function has completed on other CPUs.
211 : : *
212 : : * Returns 0 on success, else a negative status code.
213 : : */
214 : 0 : int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
215 : : int wait)
216 : : {
217 : 122 : struct call_single_data d = {
218 : : .flags = 0,
219 : : };
220 : : unsigned long flags;
221 : : int this_cpu;
222 : : int err = 0;
223 : :
224 : : /*
225 : : * prevent preemption and reschedule on another processor,
226 : : * as well as CPU removal
227 : : */
228 : 122 : this_cpu = get_cpu();
229 : :
230 : : /*
231 : : * Can deadlock when called with interrupts disabled.
232 : : * We allow cpu's that are not yet online though, as no one else can
233 : : * send smp call function interrupt to this cpu and as such deadlocks
234 : : * can't happen.
235 : : */
236 [ + - - + ]: 244 : WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
[ # # ][ - + ]
[ # # ][ # # ]
237 : : && !oops_in_progress);
238 : :
239 [ - + ]: 122 : if (cpu == this_cpu) {
240 : : local_irq_save(flags);
241 : 0 : func(info);
242 [ # # ]: 0 : local_irq_restore(flags);
243 : : } else {
244 [ + - ][ + - ]: 244 : if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
245 : : struct call_single_data *csd = &d;
246 : :
247 [ - + ]: 122 : if (!wait)
248 : 122 : csd = &__get_cpu_var(csd_data);
249 : :
250 : : csd_lock(csd);
251 : :
252 : 122 : csd->func = func;
253 : 122 : csd->info = info;
254 : 122 : generic_exec_single(cpu, csd, wait);
255 : : } else {
256 : : err = -ENXIO; /* CPU not online */
257 : : }
258 : : }
259 : :
260 : 122 : put_cpu();
261 : :
262 : 122 : return err;
263 : : }
264 : : EXPORT_SYMBOL(smp_call_function_single);
265 : :
266 : : /*
267 : : * smp_call_function_any - Run a function on any of the given cpus
268 : : * @mask: The mask of cpus it can run on.
269 : : * @func: The function to run. This must be fast and non-blocking.
270 : : * @info: An arbitrary pointer to pass to the function.
271 : : * @wait: If true, wait until function has completed.
272 : : *
273 : : * Returns 0 on success, else a negative status code (if no cpus were online).
274 : : *
275 : : * Selection preference:
276 : : * 1) current cpu if in @mask
277 : : * 2) any cpu of current node if in @mask
278 : : * 3) any other online cpu in @mask
279 : : */
280 : 0 : int smp_call_function_any(const struct cpumask *mask,
281 : : smp_call_func_t func, void *info, int wait)
282 : : {
283 : : unsigned int cpu;
284 : : const struct cpumask *nodemask;
285 : : int ret;
286 : :
287 : : /* Try for same CPU (cheapest) */
288 : 0 : cpu = get_cpu();
289 [ # # ]: 0 : if (cpumask_test_cpu(cpu, mask))
290 : : goto call;
291 : :
292 : : /* Try for same node. */
293 : 0 : nodemask = cpumask_of_node(cpu_to_node(cpu));
294 [ # # ]: 0 : for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
295 : 0 : cpu = cpumask_next_and(cpu, nodemask, mask)) {
296 [ # # ]: 0 : if (cpu_online(cpu))
297 : : goto call;
298 : : }
299 : :
300 : : /* Any online will do: smp_call_function_single handles nr_cpu_ids. */
301 : 0 : cpu = cpumask_any_and(mask, cpu_online_mask);
302 : : call:
303 : 0 : ret = smp_call_function_single(cpu, func, info, wait);
304 : 0 : put_cpu();
305 : 0 : return ret;
306 : : }
307 : : EXPORT_SYMBOL_GPL(smp_call_function_any);
308 : :
309 : : /**
310 : : * __smp_call_function_single(): Run a function on a specific CPU
311 : : * @cpu: The CPU to run on.
312 : : * @data: Pre-allocated and setup data structure
313 : : * @wait: If true, wait until function has completed on specified CPU.
314 : : *
315 : : * Like smp_call_function_single(), but allow caller to pass in a
316 : : * pre-allocated data structure. Useful for embedding @data inside
317 : : * other structures, for instance.
318 : : */
319 : 0 : void __smp_call_function_single(int cpu, struct call_single_data *csd,
320 : : int wait)
321 : : {
322 : : unsigned int this_cpu;
323 : : unsigned long flags;
324 : :
325 : 0 : this_cpu = get_cpu();
326 : : /*
327 : : * Can deadlock when called with interrupts disabled.
328 : : * We allow cpu's that are not yet online though, as no one else can
329 : : * send smp call function interrupt to this cpu and as such deadlocks
330 : : * can't happen.
331 : : */
332 [ # # ]: 0 : WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled()
[ # # # # ]
[ # # ][ # # ]
[ # # ][ # # ]
333 : : && !oops_in_progress);
334 : :
335 [ # # ]: 0 : if (cpu == this_cpu) {
336 : : local_irq_save(flags);
337 : 0 : csd->func(csd->info);
338 [ # # ]: 0 : local_irq_restore(flags);
339 : : } else {
340 : : csd_lock(csd);
341 : 0 : generic_exec_single(cpu, csd, wait);
342 : : }
343 : 0 : put_cpu();
344 : 0 : }
345 : : EXPORT_SYMBOL_GPL(__smp_call_function_single);
346 : :
347 : : /**
348 : : * smp_call_function_many(): Run a function on a set of other CPUs.
349 : : * @mask: The set of cpus to run on (only runs on online subset).
350 : : * @func: The function to run. This must be fast and non-blocking.
351 : : * @info: An arbitrary pointer to pass to the function.
352 : : * @wait: If true, wait (atomically) until function has completed
353 : : * on other CPUs.
354 : : *
355 : : * If @wait is true, then returns once @func has returned.
356 : : *
357 : : * You must not call this function with disabled interrupts or from a
358 : : * hardware interrupt handler or from a bottom half handler. Preemption
359 : : * must be disabled when calling this function.
360 : : */
361 : 0 : void smp_call_function_many(const struct cpumask *mask,
362 : : smp_call_func_t func, void *info, bool wait)
363 : : {
364 : : struct call_function_data *cfd;
365 : 36724 : int cpu, next_cpu, this_cpu = smp_processor_id();
366 : :
367 : : /*
368 : : * Can deadlock when called with interrupts disabled.
369 : : * We allow cpu's that are not yet online though, as no one else can
370 : : * send smp call function interrupt to this cpu and as such deadlocks
371 : : * can't happen.
372 : : */
373 [ + - - + ]: 73448 : WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
[ # # ][ # # ]
[ - + ][ # # ]
[ # # ]
374 : : && !oops_in_progress && !early_boot_irqs_disabled);
375 : :
376 : : /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */
377 : 36724 : cpu = cpumask_first_and(mask, cpu_online_mask);
378 [ + + ]: 36724 : if (cpu == this_cpu)
379 : 279 : cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
380 : :
381 : : /* No online cpus? We're done. */
382 [ + + ]: 36724 : if (cpu >= nr_cpu_ids)
383 : : return;
384 : :
385 : : /* Do we have another CPU which isn't us? */
386 : 122 : next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
387 [ + + ]: 122 : if (next_cpu == this_cpu)
388 : 99 : next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);
389 : :
390 : : /* Fastpath: do that cpu by itself. */
391 [ + - ]: 122 : if (next_cpu >= nr_cpu_ids) {
392 : 122 : smp_call_function_single(cpu, func, info, wait);
393 : 122 : return;
394 : : }
395 : :
396 : 0 : cfd = &__get_cpu_var(cfd_data);
397 : :
398 : : cpumask_and(cfd->cpumask, mask, cpu_online_mask);
399 : : cpumask_clear_cpu(this_cpu, cfd->cpumask);
400 : :
401 : : /* Some callers race with other cpus changing the passed mask */
402 [ # # ]: 0 : if (unlikely(!cpumask_weight(cfd->cpumask)))
403 : : return;
404 : :
405 : : /*
406 : : * After we put an entry into the list, cfd->cpumask may be cleared
407 : : * again when another CPU sends another IPI for a SMP function call, so
408 : : * cfd->cpumask will be zero.
409 : : */
410 : : cpumask_copy(cfd->cpumask_ipi, cfd->cpumask);
411 : :
412 [ # # ]: 0 : for_each_cpu(cpu, cfd->cpumask) {
413 : 0 : struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu);
414 : : struct call_single_queue *dst =
415 : 0 : &per_cpu(call_single_queue, cpu);
416 : : unsigned long flags;
417 : :
418 : : csd_lock(csd);
419 : 0 : csd->func = func;
420 : 0 : csd->info = info;
421 : :
422 : 0 : raw_spin_lock_irqsave(&dst->lock, flags);
423 : 0 : list_add_tail(&csd->list, &dst->list);
424 : 0 : raw_spin_unlock_irqrestore(&dst->lock, flags);
425 : : }
426 : :
427 : : /* Send a message to all CPUs in the map */
428 : 0 : arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
429 : :
430 [ # # ]: 0 : if (wait) {
431 [ # # ]: 0 : for_each_cpu(cpu, cfd->cpumask) {
432 : : struct call_single_data *csd;
433 : :
434 : 0 : csd = per_cpu_ptr(cfd->csd, cpu);
435 : : csd_lock_wait(csd);
436 : : }
437 : : }
438 : : }
439 : : EXPORT_SYMBOL(smp_call_function_many);
440 : :
441 : : /**
442 : : * smp_call_function(): Run a function on all other CPUs.
443 : : * @func: The function to run. This must be fast and non-blocking.
444 : : * @info: An arbitrary pointer to pass to the function.
445 : : * @wait: If true, wait (atomically) until function has completed
446 : : * on other CPUs.
447 : : *
448 : : * Returns 0.
449 : : *
450 : : * If @wait is true, then returns once @func has returned; otherwise
451 : : * it returns just before the target cpu calls @func.
452 : : *
453 : : * You must not call this function with disabled interrupts or from a
454 : : * hardware interrupt handler or from a bottom half handler.
455 : : */
456 : 0 : int smp_call_function(smp_call_func_t func, void *info, int wait)
457 : : {
458 : 11 : preempt_disable();
459 : 11 : smp_call_function_many(cpu_online_mask, func, info, wait);
460 : 11 : preempt_enable();
461 : :
462 : 0 : return 0;
463 : : }
464 : : EXPORT_SYMBOL(smp_call_function);
465 : :
466 : : /* Setup configured maximum number of CPUs to activate */
467 : : unsigned int setup_max_cpus = NR_CPUS;
468 : : EXPORT_SYMBOL(setup_max_cpus);
469 : :
470 : :
471 : : /*
472 : : * Setup routine for controlling SMP activation
473 : : *
474 : : * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
475 : : * activation entirely (the MPS table probe still happens, though).
476 : : *
477 : : * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
478 : : * greater than 0, limits the maximum number of CPUs activated in
479 : : * SMP mode to <NUM>.
480 : : */
481 : :
482 : 0 : void __weak arch_disable_smp_support(void) { }
483 : :
484 : 0 : static int __init nosmp(char *str)
485 : : {
486 : 0 : setup_max_cpus = 0;
487 : 0 : arch_disable_smp_support();
488 : :
489 : 0 : return 0;
490 : : }
491 : :
492 : : early_param("nosmp", nosmp);
493 : :
494 : : /* this is hard limit */
495 : 0 : static int __init nrcpus(char *str)
496 : : {
497 : : int nr_cpus;
498 : :
499 : 0 : get_option(&str, &nr_cpus);
500 [ # # ][ # # ]: 0 : if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
501 : 0 : nr_cpu_ids = nr_cpus;
502 : :
503 : 0 : return 0;
504 : : }
505 : :
506 : : early_param("nr_cpus", nrcpus);
507 : :
508 : 0 : static int __init maxcpus(char *str)
509 : : {
510 : 0 : get_option(&str, &setup_max_cpus);
511 [ # # ]: 0 : if (setup_max_cpus == 0)
512 : 0 : arch_disable_smp_support();
513 : :
514 : 0 : return 0;
515 : : }
516 : :
517 : : early_param("maxcpus", maxcpus);
518 : :
519 : : /* Setup number of possible processor ids */
520 : : int nr_cpu_ids __read_mostly = NR_CPUS;
521 : : EXPORT_SYMBOL(nr_cpu_ids);
522 : :
523 : : /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
524 : 0 : void __init setup_nr_cpu_ids(void)
525 : : {
526 : 0 : nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
527 : 0 : }
528 : :
529 : 0 : void __weak smp_announce(void)
530 : : {
531 : 0 : printk(KERN_INFO "Brought up %d CPUs\n", num_online_cpus());
532 : 0 : }
533 : :
534 : : /* Called by boot processor to activate the rest. */
535 : 0 : void __init smp_init(void)
536 : : {
537 : : unsigned int cpu;
538 : :
539 : 0 : idle_threads_init();
540 : :
541 : : /* FIXME: This should be done in userspace --RR */
542 [ # # ]: 0 : for_each_present_cpu(cpu) {
543 [ # # ]: 0 : if (num_online_cpus() >= setup_max_cpus)
544 : : break;
545 [ # # ]: 0 : if (!cpu_online(cpu))
546 : 0 : cpu_up(cpu);
547 : : }
548 : :
549 : : /* Any cleanup work */
550 : 0 : smp_announce();
551 : 0 : smp_cpus_done(setup_max_cpus);
552 : 0 : }
553 : :
554 : : /*
555 : : * Call a function on all processors. May be used during early boot while
556 : : * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead
557 : : * of local_irq_disable/enable().
558 : : */
559 : 0 : int on_each_cpu(void (*func) (void *info), void *info, int wait)
560 : : {
561 : : unsigned long flags;
562 : : int ret = 0;
563 : :
564 : 11 : preempt_disable();
565 : : ret = smp_call_function(func, info, wait);
566 : : local_irq_save(flags);
567 : 11 : func(info);
568 [ - + ]: 11 : local_irq_restore(flags);
569 : 11 : preempt_enable();
570 : 11 : return ret;
571 : : }
572 : : EXPORT_SYMBOL(on_each_cpu);
573 : :
574 : : /**
575 : : * on_each_cpu_mask(): Run a function on processors specified by
576 : : * cpumask, which may include the local processor.
577 : : * @mask: The set of cpus to run on (only runs on online subset).
578 : : * @func: The function to run. This must be fast and non-blocking.
579 : : * @info: An arbitrary pointer to pass to the function.
580 : : * @wait: If true, wait (atomically) until function has completed
581 : : * on other CPUs.
582 : : *
583 : : * If @wait is true, then returns once @func has returned.
584 : : *
585 : : * You must not call this function with disabled interrupts or from a
586 : : * hardware interrupt handler or from a bottom half handler. The
587 : : * exception is that it may be used during early boot while
588 : : * early_boot_irqs_disabled is set.
589 : : */
590 : 0 : void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
591 : : void *info, bool wait)
592 : : {
593 : 36713 : int cpu = get_cpu();
594 : :
595 : 36713 : smp_call_function_many(mask, func, info, wait);
596 [ + + ]: 36713 : if (cpumask_test_cpu(cpu, mask)) {
597 : : unsigned long flags;
598 : : local_irq_save(flags);
599 : 367 : func(info);
600 [ - + ]: 367 : local_irq_restore(flags);
601 : : }
602 : 36713 : put_cpu();
603 : 36713 : }
604 : : EXPORT_SYMBOL(on_each_cpu_mask);
605 : :
606 : : /*
607 : : * on_each_cpu_cond(): Call a function on each processor for which
608 : : * the supplied function cond_func returns true, optionally waiting
609 : : * for all the required CPUs to finish. This may include the local
610 : : * processor.
611 : : * @cond_func: A callback function that is passed a cpu id and
612 : : * the the info parameter. The function is called
613 : : * with preemption disabled. The function should
614 : : * return a blooean value indicating whether to IPI
615 : : * the specified CPU.
616 : : * @func: The function to run on all applicable CPUs.
617 : : * This must be fast and non-blocking.
618 : : * @info: An arbitrary pointer to pass to both functions.
619 : : * @wait: If true, wait (atomically) until function has
620 : : * completed on other CPUs.
621 : : * @gfp_flags: GFP flags to use when allocating the cpumask
622 : : * used internally by the function.
623 : : *
624 : : * The function might sleep if the GFP flags indicates a non
625 : : * atomic allocation is allowed.
626 : : *
627 : : * Preemption is disabled to protect against CPUs going offline but not online.
628 : : * CPUs going online during the call will not be seen or sent an IPI.
629 : : *
630 : : * You must not call this function with disabled interrupts or
631 : : * from a hardware interrupt handler or from a bottom half handler.
632 : : */
633 : 0 : void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
634 : : smp_call_func_t func, void *info, bool wait,
635 : : gfp_t gfp_flags)
636 : : {
637 : : cpumask_var_t cpus;
638 : : int cpu, ret;
639 : :
640 : : might_sleep_if(gfp_flags & __GFP_WAIT);
641 : :
642 : : if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {
643 : 0 : preempt_disable();
644 [ # # ]: 0 : for_each_online_cpu(cpu)
645 [ # # ]: 0 : if (cond_func(cpu, info))
646 : : cpumask_set_cpu(cpu, cpus);
647 : 0 : on_each_cpu_mask(cpus, func, info, wait);
648 : 0 : preempt_enable();
649 : : free_cpumask_var(cpus);
650 : : } else {
651 : : /*
652 : : * No free cpumask, bother. No matter, we'll
653 : : * just have to IPI them one by one.
654 : : */
655 : : preempt_disable();
656 : : for_each_online_cpu(cpu)
657 : : if (cond_func(cpu, info)) {
658 : : ret = smp_call_function_single(cpu, func,
659 : : info, wait);
660 : : WARN_ON_ONCE(!ret);
661 : : }
662 : : preempt_enable();
663 : : }
664 : 0 : }
665 : : EXPORT_SYMBOL(on_each_cpu_cond);
666 : :
667 : 0 : static void do_nothing(void *unused)
668 : : {
669 : 0 : }
670 : :
671 : : /**
672 : : * kick_all_cpus_sync - Force all cpus out of idle
673 : : *
674 : : * Used to synchronize the update of pm_idle function pointer. It's
675 : : * called after the pointer is updated and returns after the dummy
676 : : * callback function has been executed on all cpus. The execution of
677 : : * the function can only happen on the remote cpus after they have
678 : : * left the idle function which had been called via pm_idle function
679 : : * pointer. So it's guaranteed that nothing uses the previous pointer
680 : : * anymore.
681 : : */
682 : 0 : void kick_all_cpus_sync(void)
683 : : {
684 : : /* Make sure the change is visible before we kick the cpus */
685 : 0 : smp_mb();
686 : : smp_call_function(do_nothing, NULL, 1);
687 : 0 : }
688 : : EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
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