Commit | Line | Data |
---|---|---|
3d442233 JA |
1 | /* |
2 | * Generic helpers for smp ipi calls | |
3 | * | |
4 | * (C) Jens Axboe <jens.axboe@oracle.com> 2008 | |
3d442233 | 5 | */ |
3d442233 | 6 | #include <linux/rcupdate.h> |
59190f42 | 7 | #include <linux/rculist.h> |
641cd4cf | 8 | #include <linux/kernel.h> |
9984de1a | 9 | #include <linux/export.h> |
0b13fda1 IM |
10 | #include <linux/percpu.h> |
11 | #include <linux/init.h> | |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
3d442233 | 13 | #include <linux/smp.h> |
8969a5ed | 14 | #include <linux/cpu.h> |
3d442233 | 15 | |
3bb5d2ee SS |
16 | #include "smpboot.h" |
17 | ||
351f8f8e | 18 | #ifdef CONFIG_USE_GENERIC_SMP_HELPERS |
3d442233 | 19 | enum { |
6e275637 | 20 | CSD_FLAG_LOCK = 0x01, |
3d442233 JA |
21 | }; |
22 | ||
23 | struct call_function_data { | |
9a46ad6d | 24 | struct call_single_data __percpu *csd; |
0b13fda1 | 25 | cpumask_var_t cpumask; |
f44310b9 | 26 | cpumask_var_t cpumask_ipi; |
3d442233 JA |
27 | }; |
28 | ||
e03bcb68 MM |
29 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data); |
30 | ||
3d442233 | 31 | struct call_single_queue { |
0b13fda1 | 32 | struct list_head list; |
9f5a5621 | 33 | raw_spinlock_t lock; |
3d442233 JA |
34 | }; |
35 | ||
e03bcb68 | 36 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_queue, call_single_queue); |
8969a5ed PZ |
37 | |
38 | static int | |
39 | hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
40 | { | |
41 | long cpu = (long)hcpu; | |
42 | 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: | |
eaa95840 | 47 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, |
8969a5ed | 48 | cpu_to_node(cpu))) |
80b5184c | 49 | return notifier_from_errno(-ENOMEM); |
f44310b9 WY |
50 | if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL, |
51 | cpu_to_node(cpu))) | |
52 | return notifier_from_errno(-ENOMEM); | |
9a46ad6d SL |
53 | cfd->csd = alloc_percpu(struct call_single_data); |
54 | if (!cfd->csd) { | |
55 | free_cpumask_var(cfd->cpumask); | |
56 | return notifier_from_errno(-ENOMEM); | |
57 | } | |
8969a5ed PZ |
58 | break; |
59 | ||
69dd647f | 60 | #ifdef CONFIG_HOTPLUG_CPU |
8969a5ed PZ |
61 | case CPU_UP_CANCELED: |
62 | case CPU_UP_CANCELED_FROZEN: | |
63 | ||
64 | case CPU_DEAD: | |
65 | case CPU_DEAD_FROZEN: | |
66 | free_cpumask_var(cfd->cpumask); | |
f44310b9 | 67 | free_cpumask_var(cfd->cpumask_ipi); |
9a46ad6d | 68 | free_percpu(cfd->csd); |
8969a5ed PZ |
69 | break; |
70 | #endif | |
71 | }; | |
72 | ||
73 | return NOTIFY_OK; | |
74 | } | |
75 | ||
76 | static struct notifier_block __cpuinitdata hotplug_cfd_notifier = { | |
0b13fda1 | 77 | .notifier_call = hotplug_cfd, |
8969a5ed PZ |
78 | }; |
79 | ||
d8ad7d11 | 80 | void __init call_function_init(void) |
3d442233 | 81 | { |
8969a5ed | 82 | void *cpu = (void *)(long)smp_processor_id(); |
3d442233 JA |
83 | int i; |
84 | ||
85 | for_each_possible_cpu(i) { | |
86 | struct call_single_queue *q = &per_cpu(call_single_queue, i); | |
87 | ||
9f5a5621 | 88 | raw_spin_lock_init(&q->lock); |
3d442233 JA |
89 | INIT_LIST_HEAD(&q->list); |
90 | } | |
8969a5ed PZ |
91 | |
92 | hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu); | |
93 | register_cpu_notifier(&hotplug_cfd_notifier); | |
3d442233 JA |
94 | } |
95 | ||
8969a5ed PZ |
96 | /* |
97 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources | |
98 | * | |
0b13fda1 IM |
99 | * For non-synchronous ipi calls the csd can still be in use by the |
100 | * previous function call. For multi-cpu calls its even more interesting | |
101 | * as we'll have to ensure no other cpu is observing our csd. | |
8969a5ed | 102 | */ |
e1d12f32 | 103 | static void csd_lock_wait(struct call_single_data *csd) |
8969a5ed | 104 | { |
e1d12f32 | 105 | while (csd->flags & CSD_FLAG_LOCK) |
8969a5ed | 106 | cpu_relax(); |
6e275637 PZ |
107 | } |
108 | ||
e1d12f32 | 109 | static void csd_lock(struct call_single_data *csd) |
6e275637 | 110 | { |
e1d12f32 AM |
111 | csd_lock_wait(csd); |
112 | csd->flags |= CSD_FLAG_LOCK; | |
8969a5ed PZ |
113 | |
114 | /* | |
0b13fda1 IM |
115 | * prevent CPU from reordering the above assignment |
116 | * to ->flags with any subsequent assignments to other | |
117 | * fields of the specified call_single_data structure: | |
8969a5ed | 118 | */ |
8969a5ed PZ |
119 | smp_mb(); |
120 | } | |
121 | ||
e1d12f32 | 122 | static void csd_unlock(struct call_single_data *csd) |
8969a5ed | 123 | { |
e1d12f32 | 124 | WARN_ON(!(csd->flags & CSD_FLAG_LOCK)); |
0b13fda1 | 125 | |
8969a5ed | 126 | /* |
0b13fda1 | 127 | * ensure we're all done before releasing data: |
8969a5ed PZ |
128 | */ |
129 | smp_mb(); | |
0b13fda1 | 130 | |
e1d12f32 | 131 | csd->flags &= ~CSD_FLAG_LOCK; |
3d442233 JA |
132 | } |
133 | ||
134 | /* | |
0b13fda1 IM |
135 | * Insert a previously allocated call_single_data element |
136 | * for execution on the given CPU. data must already have | |
137 | * ->func, ->info, and ->flags set. | |
3d442233 | 138 | */ |
6e275637 | 139 | static |
e1d12f32 | 140 | void generic_exec_single(int cpu, struct call_single_data *csd, int wait) |
3d442233 JA |
141 | { |
142 | struct call_single_queue *dst = &per_cpu(call_single_queue, cpu); | |
3d442233 | 143 | unsigned long flags; |
6e275637 | 144 | int ipi; |
3d442233 | 145 | |
9f5a5621 | 146 | raw_spin_lock_irqsave(&dst->lock, flags); |
3d442233 | 147 | ipi = list_empty(&dst->list); |
e1d12f32 | 148 | list_add_tail(&csd->list, &dst->list); |
9f5a5621 | 149 | raw_spin_unlock_irqrestore(&dst->lock, flags); |
3d442233 | 150 | |
561920a0 | 151 | /* |
15d0d3b3 NP |
152 | * The list addition should be visible before sending the IPI |
153 | * handler locks the list to pull the entry off it because of | |
154 | * normal cache coherency rules implied by spinlocks. | |
155 | * | |
156 | * If IPIs can go out of order to the cache coherency protocol | |
157 | * in an architecture, sufficient synchronisation should be added | |
158 | * to arch code to make it appear to obey cache coherency WRT | |
0b13fda1 IM |
159 | * locking and barrier primitives. Generic code isn't really |
160 | * equipped to do the right thing... | |
561920a0 | 161 | */ |
3d442233 JA |
162 | if (ipi) |
163 | arch_send_call_function_single_ipi(cpu); | |
164 | ||
165 | if (wait) | |
e1d12f32 | 166 | csd_lock_wait(csd); |
3d442233 JA |
167 | } |
168 | ||
3d442233 | 169 | /* |
0b13fda1 IM |
170 | * Invoked by arch to handle an IPI for call function single. Must be |
171 | * called from the arch with interrupts disabled. | |
3d442233 JA |
172 | */ |
173 | void generic_smp_call_function_single_interrupt(void) | |
174 | { | |
175 | struct call_single_queue *q = &__get_cpu_var(call_single_queue); | |
0b13fda1 | 176 | LIST_HEAD(list); |
3d442233 | 177 | |
269c861b SS |
178 | /* |
179 | * Shouldn't receive this interrupt on a cpu that is not yet online. | |
180 | */ | |
181 | WARN_ON_ONCE(!cpu_online(smp_processor_id())); | |
182 | ||
9f5a5621 | 183 | raw_spin_lock(&q->lock); |
15d0d3b3 | 184 | list_replace_init(&q->list, &list); |
9f5a5621 | 185 | raw_spin_unlock(&q->lock); |
3d442233 | 186 | |
15d0d3b3 | 187 | while (!list_empty(&list)) { |
e1d12f32 AM |
188 | struct call_single_data *csd; |
189 | unsigned int csd_flags; | |
3d442233 | 190 | |
e1d12f32 AM |
191 | csd = list_entry(list.next, struct call_single_data, list); |
192 | list_del(&csd->list); | |
3d442233 | 193 | |
3d442233 | 194 | /* |
e1d12f32 | 195 | * 'csd' can be invalid after this call if flags == 0 |
0b13fda1 IM |
196 | * (when called through generic_exec_single()), |
197 | * so save them away before making the call: | |
3d442233 | 198 | */ |
e1d12f32 | 199 | csd_flags = csd->flags; |
15d0d3b3 | 200 | |
e1d12f32 | 201 | csd->func(csd->info); |
15d0d3b3 | 202 | |
8969a5ed | 203 | /* |
0b13fda1 | 204 | * Unlocked CSDs are valid through generic_exec_single(): |
8969a5ed | 205 | */ |
e1d12f32 AM |
206 | if (csd_flags & CSD_FLAG_LOCK) |
207 | csd_unlock(csd); | |
3d442233 JA |
208 | } |
209 | } | |
210 | ||
e03bcb68 | 211 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); |
d7240b98 | 212 | |
3d442233 JA |
213 | /* |
214 | * smp_call_function_single - Run a function on a specific CPU | |
215 | * @func: The function to run. This must be fast and non-blocking. | |
216 | * @info: An arbitrary pointer to pass to the function. | |
3d442233 JA |
217 | * @wait: If true, wait until function has completed on other CPUs. |
218 | * | |
72f279b2 | 219 | * Returns 0 on success, else a negative status code. |
3d442233 | 220 | */ |
3a5f65df | 221 | int smp_call_function_single(int cpu, smp_call_func_t func, void *info, |
8691e5a8 | 222 | int wait) |
3d442233 | 223 | { |
8969a5ed PZ |
224 | struct call_single_data d = { |
225 | .flags = 0, | |
226 | }; | |
3d442233 | 227 | unsigned long flags; |
0b13fda1 | 228 | int this_cpu; |
f73be6de | 229 | int err = 0; |
3d442233 | 230 | |
0b13fda1 IM |
231 | /* |
232 | * prevent preemption and reschedule on another processor, | |
233 | * as well as CPU removal | |
234 | */ | |
235 | this_cpu = get_cpu(); | |
236 | ||
269c861b SS |
237 | /* |
238 | * Can deadlock when called with interrupts disabled. | |
239 | * We allow cpu's that are not yet online though, as no one else can | |
240 | * send smp call function interrupt to this cpu and as such deadlocks | |
241 | * can't happen. | |
242 | */ | |
243 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
244 | && !oops_in_progress); | |
3d442233 | 245 | |
0b13fda1 | 246 | if (cpu == this_cpu) { |
3d442233 JA |
247 | local_irq_save(flags); |
248 | func(info); | |
249 | local_irq_restore(flags); | |
0b13fda1 IM |
250 | } else { |
251 | if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { | |
e1d12f32 | 252 | struct call_single_data *csd = &d; |
3d442233 | 253 | |
0b13fda1 | 254 | if (!wait) |
e1d12f32 | 255 | csd = &__get_cpu_var(csd_data); |
6e275637 | 256 | |
e1d12f32 | 257 | csd_lock(csd); |
3d442233 | 258 | |
e1d12f32 AM |
259 | csd->func = func; |
260 | csd->info = info; | |
261 | generic_exec_single(cpu, csd, wait); | |
0b13fda1 IM |
262 | } else { |
263 | err = -ENXIO; /* CPU not online */ | |
264 | } | |
3d442233 JA |
265 | } |
266 | ||
267 | put_cpu(); | |
0b13fda1 | 268 | |
f73be6de | 269 | return err; |
3d442233 JA |
270 | } |
271 | EXPORT_SYMBOL(smp_call_function_single); | |
272 | ||
6fa3eb70 S |
273 | /* This function can be used by MTK Monitor only */ |
274 | /* Dont use this function directly */ | |
275 | int mtk_smp_call_function_single(int cpu, smp_call_func_t func, void *info, | |
276 | int wait) | |
277 | { | |
278 | struct call_single_data d = { | |
279 | .flags = 0, | |
280 | }; | |
281 | unsigned long flags; | |
282 | int this_cpu; | |
283 | int err = 0; | |
284 | ||
285 | /* | |
286 | * prevent preemption and reschedule on another processor, | |
287 | * as well as CPU removal | |
288 | */ | |
289 | this_cpu = get_cpu(); | |
290 | ||
291 | if (cpu == this_cpu) { | |
292 | local_irq_save(flags); | |
293 | func(info); | |
294 | local_irq_restore(flags); | |
295 | } else { | |
296 | if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { | |
297 | struct call_single_data *data = &d; | |
298 | ||
299 | if (!wait) | |
300 | data = &__get_cpu_var(csd_data); | |
301 | ||
302 | csd_lock(data); | |
303 | ||
304 | cpumask_set_cpu(cpu, data->cpumask); | |
305 | data->func = func; | |
306 | data->info = info; | |
307 | generic_exec_single(cpu, data, wait); | |
308 | } else { | |
309 | err = -ENXIO; /* CPU not online */ | |
310 | } | |
311 | } | |
312 | ||
313 | put_cpu(); | |
314 | ||
315 | return err; | |
316 | } | |
317 | ||
2ea6dec4 RR |
318 | /* |
319 | * smp_call_function_any - Run a function on any of the given cpus | |
320 | * @mask: The mask of cpus it can run on. | |
321 | * @func: The function to run. This must be fast and non-blocking. | |
322 | * @info: An arbitrary pointer to pass to the function. | |
323 | * @wait: If true, wait until function has completed. | |
324 | * | |
325 | * Returns 0 on success, else a negative status code (if no cpus were online). | |
326 | * Note that @wait will be implicitly turned on in case of allocation failures, | |
327 | * since we fall back to on-stack allocation. | |
328 | * | |
329 | * Selection preference: | |
330 | * 1) current cpu if in @mask | |
331 | * 2) any cpu of current node if in @mask | |
332 | * 3) any other online cpu in @mask | |
333 | */ | |
334 | int smp_call_function_any(const struct cpumask *mask, | |
3a5f65df | 335 | smp_call_func_t func, void *info, int wait) |
2ea6dec4 RR |
336 | { |
337 | unsigned int cpu; | |
338 | const struct cpumask *nodemask; | |
339 | int ret; | |
340 | ||
341 | /* Try for same CPU (cheapest) */ | |
342 | cpu = get_cpu(); | |
343 | if (cpumask_test_cpu(cpu, mask)) | |
344 | goto call; | |
345 | ||
346 | /* Try for same node. */ | |
af2422c4 | 347 | nodemask = cpumask_of_node(cpu_to_node(cpu)); |
2ea6dec4 RR |
348 | for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; |
349 | cpu = cpumask_next_and(cpu, nodemask, mask)) { | |
350 | if (cpu_online(cpu)) | |
351 | goto call; | |
352 | } | |
353 | ||
354 | /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ | |
355 | cpu = cpumask_any_and(mask, cpu_online_mask); | |
356 | call: | |
357 | ret = smp_call_function_single(cpu, func, info, wait); | |
358 | put_cpu(); | |
359 | return ret; | |
360 | } | |
361 | EXPORT_SYMBOL_GPL(smp_call_function_any); | |
362 | ||
3d442233 | 363 | /** |
27c379f7 | 364 | * __smp_call_function_single(): Run a function on a specific CPU |
3d442233 JA |
365 | * @cpu: The CPU to run on. |
366 | * @data: Pre-allocated and setup data structure | |
27c379f7 | 367 | * @wait: If true, wait until function has completed on specified CPU. |
3d442233 | 368 | * |
0b13fda1 IM |
369 | * Like smp_call_function_single(), but allow caller to pass in a |
370 | * pre-allocated data structure. Useful for embedding @data inside | |
371 | * other structures, for instance. | |
3d442233 | 372 | */ |
e1d12f32 | 373 | void __smp_call_function_single(int cpu, struct call_single_data *csd, |
6e275637 | 374 | int wait) |
3d442233 | 375 | { |
27c379f7 HC |
376 | unsigned int this_cpu; |
377 | unsigned long flags; | |
6e275637 | 378 | |
27c379f7 | 379 | this_cpu = get_cpu(); |
269c861b SS |
380 | /* |
381 | * Can deadlock when called with interrupts disabled. | |
382 | * We allow cpu's that are not yet online though, as no one else can | |
383 | * send smp call function interrupt to this cpu and as such deadlocks | |
384 | * can't happen. | |
385 | */ | |
386 | WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled() | |
387 | && !oops_in_progress); | |
3d442233 | 388 | |
27c379f7 HC |
389 | if (cpu == this_cpu) { |
390 | local_irq_save(flags); | |
e1d12f32 | 391 | csd->func(csd->info); |
27c379f7 HC |
392 | local_irq_restore(flags); |
393 | } else { | |
e1d12f32 AM |
394 | csd_lock(csd); |
395 | generic_exec_single(cpu, csd, wait); | |
27c379f7 HC |
396 | } |
397 | put_cpu(); | |
3d442233 JA |
398 | } |
399 | ||
400 | /** | |
54b11e6d RR |
401 | * smp_call_function_many(): Run a function on a set of other CPUs. |
402 | * @mask: The set of cpus to run on (only runs on online subset). | |
3d442233 JA |
403 | * @func: The function to run. This must be fast and non-blocking. |
404 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
405 | * @wait: If true, wait (atomically) until function has completed |
406 | * on other CPUs. | |
3d442233 | 407 | * |
72f279b2 | 408 | * If @wait is true, then returns once @func has returned. |
3d442233 JA |
409 | * |
410 | * You must not call this function with disabled interrupts or from a | |
411 | * hardware interrupt handler or from a bottom half handler. Preemption | |
412 | * must be disabled when calling this function. | |
413 | */ | |
54b11e6d | 414 | void smp_call_function_many(const struct cpumask *mask, |
3a5f65df | 415 | smp_call_func_t func, void *info, bool wait) |
3d442233 | 416 | { |
e1d12f32 | 417 | struct call_function_data *cfd; |
9a46ad6d | 418 | int cpu, next_cpu, this_cpu = smp_processor_id(); |
3d442233 | 419 | |
269c861b SS |
420 | /* |
421 | * Can deadlock when called with interrupts disabled. | |
422 | * We allow cpu's that are not yet online though, as no one else can | |
423 | * send smp call function interrupt to this cpu and as such deadlocks | |
424 | * can't happen. | |
425 | */ | |
426 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
bd924e8c | 427 | && !oops_in_progress && !early_boot_irqs_disabled); |
3d442233 | 428 | |
723aae25 | 429 | /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */ |
54b11e6d | 430 | cpu = cpumask_first_and(mask, cpu_online_mask); |
0b13fda1 | 431 | if (cpu == this_cpu) |
54b11e6d | 432 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
0b13fda1 | 433 | |
54b11e6d RR |
434 | /* No online cpus? We're done. */ |
435 | if (cpu >= nr_cpu_ids) | |
436 | return; | |
437 | ||
438 | /* Do we have another CPU which isn't us? */ | |
439 | next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask); | |
0b13fda1 | 440 | if (next_cpu == this_cpu) |
54b11e6d RR |
441 | next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask); |
442 | ||
443 | /* Fastpath: do that cpu by itself. */ | |
444 | if (next_cpu >= nr_cpu_ids) { | |
445 | smp_call_function_single(cpu, func, info, wait); | |
446 | return; | |
3d442233 JA |
447 | } |
448 | ||
e1d12f32 | 449 | cfd = &__get_cpu_var(cfd_data); |
45a57919 | 450 | |
e1d12f32 AM |
451 | cpumask_and(cfd->cpumask, mask, cpu_online_mask); |
452 | cpumask_clear_cpu(this_cpu, cfd->cpumask); | |
723aae25 MM |
453 | |
454 | /* Some callers race with other cpus changing the passed mask */ | |
e1d12f32 | 455 | if (unlikely(!cpumask_weight(cfd->cpumask))) |
723aae25 | 456 | return; |
3d442233 | 457 | |
f44310b9 | 458 | /* |
e1d12f32 AM |
459 | * After we put an entry into the list, cfd->cpumask may be cleared |
460 | * again when another CPU sends another IPI for a SMP function call, so | |
461 | * cfd->cpumask will be zero. | |
f44310b9 | 462 | */ |
e1d12f32 | 463 | cpumask_copy(cfd->cpumask_ipi, cfd->cpumask); |
3d442233 | 464 | |
e1d12f32 AM |
465 | for_each_cpu(cpu, cfd->cpumask) { |
466 | struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu); | |
9a46ad6d SL |
467 | struct call_single_queue *dst = |
468 | &per_cpu(call_single_queue, cpu); | |
469 | unsigned long flags; | |
470 | ||
471 | csd_lock(csd); | |
472 | csd->func = func; | |
473 | csd->info = info; | |
474 | ||
475 | raw_spin_lock_irqsave(&dst->lock, flags); | |
476 | list_add_tail(&csd->list, &dst->list); | |
477 | raw_spin_unlock_irqrestore(&dst->lock, flags); | |
478 | } | |
561920a0 | 479 | |
3d442233 | 480 | /* Send a message to all CPUs in the map */ |
e1d12f32 | 481 | arch_send_call_function_ipi_mask(cfd->cpumask_ipi); |
3d442233 | 482 | |
9a46ad6d | 483 | if (wait) { |
e1d12f32 AM |
484 | for_each_cpu(cpu, cfd->cpumask) { |
485 | struct call_single_data *csd; | |
486 | ||
487 | csd = per_cpu_ptr(cfd->csd, cpu); | |
9a46ad6d SL |
488 | csd_lock_wait(csd); |
489 | } | |
490 | } | |
3d442233 | 491 | } |
54b11e6d | 492 | EXPORT_SYMBOL(smp_call_function_many); |
3d442233 JA |
493 | |
494 | /** | |
495 | * smp_call_function(): Run a function on all other CPUs. | |
496 | * @func: The function to run. This must be fast and non-blocking. | |
497 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
498 | * @wait: If true, wait (atomically) until function has completed |
499 | * on other CPUs. | |
3d442233 | 500 | * |
54b11e6d | 501 | * Returns 0. |
3d442233 JA |
502 | * |
503 | * If @wait is true, then returns once @func has returned; otherwise | |
72f279b2 | 504 | * it returns just before the target cpu calls @func. |
3d442233 JA |
505 | * |
506 | * You must not call this function with disabled interrupts or from a | |
507 | * hardware interrupt handler or from a bottom half handler. | |
508 | */ | |
3a5f65df | 509 | int smp_call_function(smp_call_func_t func, void *info, int wait) |
3d442233 | 510 | { |
3d442233 | 511 | preempt_disable(); |
54b11e6d | 512 | smp_call_function_many(cpu_online_mask, func, info, wait); |
3d442233 | 513 | preempt_enable(); |
0b13fda1 | 514 | |
54b11e6d | 515 | return 0; |
3d442233 JA |
516 | } |
517 | EXPORT_SYMBOL(smp_call_function); | |
351f8f8e AW |
518 | #endif /* USE_GENERIC_SMP_HELPERS */ |
519 | ||
34db18a0 AW |
520 | /* Setup configured maximum number of CPUs to activate */ |
521 | unsigned int setup_max_cpus = NR_CPUS; | |
522 | EXPORT_SYMBOL(setup_max_cpus); | |
523 | ||
524 | ||
525 | /* | |
526 | * Setup routine for controlling SMP activation | |
527 | * | |
528 | * Command-line option of "nosmp" or "maxcpus=0" will disable SMP | |
529 | * activation entirely (the MPS table probe still happens, though). | |
530 | * | |
531 | * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer | |
532 | * greater than 0, limits the maximum number of CPUs activated in | |
533 | * SMP mode to <NUM>. | |
534 | */ | |
535 | ||
536 | void __weak arch_disable_smp_support(void) { } | |
537 | ||
538 | static int __init nosmp(char *str) | |
539 | { | |
540 | setup_max_cpus = 0; | |
541 | arch_disable_smp_support(); | |
542 | ||
543 | return 0; | |
544 | } | |
545 | ||
546 | early_param("nosmp", nosmp); | |
547 | ||
548 | /* this is hard limit */ | |
549 | static int __init nrcpus(char *str) | |
550 | { | |
551 | int nr_cpus; | |
552 | ||
553 | get_option(&str, &nr_cpus); | |
554 | if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) | |
555 | nr_cpu_ids = nr_cpus; | |
556 | ||
557 | return 0; | |
558 | } | |
559 | ||
560 | early_param("nr_cpus", nrcpus); | |
561 | ||
562 | static int __init maxcpus(char *str) | |
563 | { | |
564 | get_option(&str, &setup_max_cpus); | |
565 | if (setup_max_cpus == 0) | |
566 | arch_disable_smp_support(); | |
567 | ||
568 | return 0; | |
569 | } | |
570 | ||
571 | early_param("maxcpus", maxcpus); | |
572 | ||
573 | /* Setup number of possible processor ids */ | |
574 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
575 | EXPORT_SYMBOL(nr_cpu_ids); | |
576 | ||
577 | /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ | |
578 | void __init setup_nr_cpu_ids(void) | |
579 | { | |
580 | nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; | |
581 | } | |
582 | ||
583 | /* Called by boot processor to activate the rest. */ | |
584 | void __init smp_init(void) | |
585 | { | |
586 | unsigned int cpu; | |
587 | ||
3bb5d2ee SS |
588 | idle_threads_init(); |
589 | ||
34db18a0 AW |
590 | /* FIXME: This should be done in userspace --RR */ |
591 | for_each_present_cpu(cpu) { | |
592 | if (num_online_cpus() >= setup_max_cpus) | |
593 | break; | |
594 | if (!cpu_online(cpu)) | |
595 | cpu_up(cpu); | |
596 | } | |
597 | ||
598 | /* Any cleanup work */ | |
599 | printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); | |
600 | smp_cpus_done(setup_max_cpus); | |
601 | } | |
602 | ||
351f8f8e | 603 | /* |
bd924e8c TH |
604 | * Call a function on all processors. May be used during early boot while |
605 | * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead | |
606 | * of local_irq_disable/enable(). | |
351f8f8e AW |
607 | */ |
608 | int on_each_cpu(void (*func) (void *info), void *info, int wait) | |
609 | { | |
bd924e8c | 610 | unsigned long flags; |
351f8f8e AW |
611 | int ret = 0; |
612 | ||
613 | preempt_disable(); | |
614 | ret = smp_call_function(func, info, wait); | |
bd924e8c | 615 | local_irq_save(flags); |
351f8f8e | 616 | func(info); |
bd924e8c | 617 | local_irq_restore(flags); |
351f8f8e AW |
618 | preempt_enable(); |
619 | return ret; | |
620 | } | |
621 | EXPORT_SYMBOL(on_each_cpu); | |
3fc498f1 GBY |
622 | |
623 | /** | |
624 | * on_each_cpu_mask(): Run a function on processors specified by | |
625 | * cpumask, which may include the local processor. | |
626 | * @mask: The set of cpus to run on (only runs on online subset). | |
627 | * @func: The function to run. This must be fast and non-blocking. | |
628 | * @info: An arbitrary pointer to pass to the function. | |
629 | * @wait: If true, wait (atomically) until function has completed | |
630 | * on other CPUs. | |
631 | * | |
632 | * If @wait is true, then returns once @func has returned. | |
633 | * | |
634 | * You must not call this function with disabled interrupts or | |
635 | * from a hardware interrupt handler or from a bottom half handler. | |
636 | */ | |
637 | void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, | |
638 | void *info, bool wait) | |
639 | { | |
640 | int cpu = get_cpu(); | |
641 | ||
642 | smp_call_function_many(mask, func, info, wait); | |
643 | if (cpumask_test_cpu(cpu, mask)) { | |
644 | local_irq_disable(); | |
645 | func(info); | |
646 | local_irq_enable(); | |
647 | } | |
648 | put_cpu(); | |
649 | } | |
650 | EXPORT_SYMBOL(on_each_cpu_mask); | |
b3a7e98e GBY |
651 | |
652 | /* | |
653 | * on_each_cpu_cond(): Call a function on each processor for which | |
654 | * the supplied function cond_func returns true, optionally waiting | |
655 | * for all the required CPUs to finish. This may include the local | |
656 | * processor. | |
657 | * @cond_func: A callback function that is passed a cpu id and | |
658 | * the the info parameter. The function is called | |
659 | * with preemption disabled. The function should | |
660 | * return a blooean value indicating whether to IPI | |
661 | * the specified CPU. | |
662 | * @func: The function to run on all applicable CPUs. | |
663 | * This must be fast and non-blocking. | |
664 | * @info: An arbitrary pointer to pass to both functions. | |
665 | * @wait: If true, wait (atomically) until function has | |
666 | * completed on other CPUs. | |
667 | * @gfp_flags: GFP flags to use when allocating the cpumask | |
668 | * used internally by the function. | |
669 | * | |
670 | * The function might sleep if the GFP flags indicates a non | |
671 | * atomic allocation is allowed. | |
672 | * | |
673 | * Preemption is disabled to protect against CPUs going offline but not online. | |
674 | * CPUs going online during the call will not be seen or sent an IPI. | |
675 | * | |
676 | * You must not call this function with disabled interrupts or | |
677 | * from a hardware interrupt handler or from a bottom half handler. | |
678 | */ | |
679 | void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), | |
680 | smp_call_func_t func, void *info, bool wait, | |
681 | gfp_t gfp_flags) | |
682 | { | |
683 | cpumask_var_t cpus; | |
684 | int cpu, ret; | |
685 | ||
686 | might_sleep_if(gfp_flags & __GFP_WAIT); | |
687 | ||
688 | if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) { | |
689 | preempt_disable(); | |
690 | for_each_online_cpu(cpu) | |
691 | if (cond_func(cpu, info)) | |
692 | cpumask_set_cpu(cpu, cpus); | |
693 | on_each_cpu_mask(cpus, func, info, wait); | |
694 | preempt_enable(); | |
695 | free_cpumask_var(cpus); | |
696 | } else { | |
697 | /* | |
698 | * No free cpumask, bother. No matter, we'll | |
699 | * just have to IPI them one by one. | |
700 | */ | |
701 | preempt_disable(); | |
702 | for_each_online_cpu(cpu) | |
703 | if (cond_func(cpu, info)) { | |
704 | ret = smp_call_function_single(cpu, func, | |
705 | info, wait); | |
a8fd5194 | 706 | WARN_ON_ONCE(ret); |
b3a7e98e GBY |
707 | } |
708 | preempt_enable(); | |
709 | } | |
710 | } | |
711 | EXPORT_SYMBOL(on_each_cpu_cond); | |
f37f435f TG |
712 | |
713 | static void do_nothing(void *unused) | |
714 | { | |
715 | } | |
716 | ||
717 | /** | |
718 | * kick_all_cpus_sync - Force all cpus out of idle | |
719 | * | |
720 | * Used to synchronize the update of pm_idle function pointer. It's | |
721 | * called after the pointer is updated and returns after the dummy | |
722 | * callback function has been executed on all cpus. The execution of | |
723 | * the function can only happen on the remote cpus after they have | |
724 | * left the idle function which had been called via pm_idle function | |
725 | * pointer. So it's guaranteed that nothing uses the previous pointer | |
726 | * anymore. | |
727 | */ | |
728 | void kick_all_cpus_sync(void) | |
729 | { | |
730 | /* Make sure the change is visible before we kick the cpus */ | |
731 | smp_mb(); | |
732 | smp_call_function(do_nothing, NULL, 1); | |
733 | } | |
734 | EXPORT_SYMBOL_GPL(kick_all_cpus_sync); |