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Commit | Line | Data |
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3d442233 JA |
1 | /* |
2 | * Generic helpers for smp ipi calls | |
3 | * | |
4 | * (C) Jens Axboe <jens.axboe@oracle.com> 2008 | |
3d442233 | 5 | */ |
ca7dfdbb ME |
6 | |
7 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
8 | ||
47885016 | 9 | #include <linux/irq_work.h> |
3d442233 | 10 | #include <linux/rcupdate.h> |
59190f42 | 11 | #include <linux/rculist.h> |
641cd4cf | 12 | #include <linux/kernel.h> |
9984de1a | 13 | #include <linux/export.h> |
0b13fda1 IM |
14 | #include <linux/percpu.h> |
15 | #include <linux/init.h> | |
5a0e3ad6 | 16 | #include <linux/gfp.h> |
3d442233 | 17 | #include <linux/smp.h> |
8969a5ed | 18 | #include <linux/cpu.h> |
c6f4459f | 19 | #include <linux/sched.h> |
4c822698 | 20 | #include <linux/sched/idle.h> |
47ae4b05 | 21 | #include <linux/hypervisor.h> |
3d442233 | 22 | |
3bb5d2ee SS |
23 | #include "smpboot.h" |
24 | ||
3d442233 | 25 | enum { |
6e275637 | 26 | CSD_FLAG_LOCK = 0x01, |
8053871d | 27 | CSD_FLAG_SYNCHRONOUS = 0x02, |
3d442233 JA |
28 | }; |
29 | ||
30 | struct call_function_data { | |
9a46ad6d | 31 | struct call_single_data __percpu *csd; |
0b13fda1 | 32 | cpumask_var_t cpumask; |
3fc5b3b6 | 33 | cpumask_var_t cpumask_ipi; |
3d442233 JA |
34 | }; |
35 | ||
e03bcb68 MM |
36 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data); |
37 | ||
6897fc22 | 38 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); |
8969a5ed | 39 | |
8d056c48 SB |
40 | static void flush_smp_call_function_queue(bool warn_cpu_offline); |
41 | ||
31487f83 | 42 | int smpcfd_prepare_cpu(unsigned int cpu) |
8969a5ed | 43 | { |
8969a5ed PZ |
44 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); |
45 | ||
31487f83 RW |
46 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, |
47 | cpu_to_node(cpu))) | |
48 | return -ENOMEM; | |
3fc5b3b6 AL |
49 | if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL, |
50 | cpu_to_node(cpu))) { | |
51 | free_cpumask_var(cfd->cpumask); | |
52 | return -ENOMEM; | |
53 | } | |
31487f83 RW |
54 | cfd->csd = alloc_percpu(struct call_single_data); |
55 | if (!cfd->csd) { | |
8969a5ed | 56 | free_cpumask_var(cfd->cpumask); |
3fc5b3b6 | 57 | free_cpumask_var(cfd->cpumask_ipi); |
31487f83 RW |
58 | return -ENOMEM; |
59 | } | |
60 | ||
61 | return 0; | |
8969a5ed PZ |
62 | } |
63 | ||
31487f83 RW |
64 | int smpcfd_dead_cpu(unsigned int cpu) |
65 | { | |
66 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); | |
67 | ||
68 | free_cpumask_var(cfd->cpumask); | |
3fc5b3b6 | 69 | free_cpumask_var(cfd->cpumask_ipi); |
31487f83 RW |
70 | free_percpu(cfd->csd); |
71 | return 0; | |
72 | } | |
73 | ||
74 | int smpcfd_dying_cpu(unsigned int cpu) | |
75 | { | |
76 | /* | |
77 | * The IPIs for the smp-call-function callbacks queued by other | |
78 | * CPUs might arrive late, either due to hardware latencies or | |
79 | * because this CPU disabled interrupts (inside stop-machine) | |
80 | * before the IPIs were sent. So flush out any pending callbacks | |
81 | * explicitly (without waiting for the IPIs to arrive), to | |
82 | * ensure that the outgoing CPU doesn't go offline with work | |
83 | * still pending. | |
84 | */ | |
85 | flush_smp_call_function_queue(false); | |
86 | return 0; | |
87 | } | |
8969a5ed | 88 | |
d8ad7d11 | 89 | void __init call_function_init(void) |
3d442233 JA |
90 | { |
91 | int i; | |
92 | ||
6897fc22 CH |
93 | for_each_possible_cpu(i) |
94 | init_llist_head(&per_cpu(call_single_queue, i)); | |
8969a5ed | 95 | |
31487f83 | 96 | smpcfd_prepare_cpu(smp_processor_id()); |
3d442233 JA |
97 | } |
98 | ||
8969a5ed PZ |
99 | /* |
100 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources | |
101 | * | |
0b13fda1 IM |
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. | |
8969a5ed | 105 | */ |
90d10984 | 106 | static __always_inline void csd_lock_wait(struct call_single_data *csd) |
8969a5ed | 107 | { |
1f03e8d2 | 108 | smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK)); |
6e275637 PZ |
109 | } |
110 | ||
90d10984 | 111 | static __always_inline void csd_lock(struct call_single_data *csd) |
6e275637 | 112 | { |
e1d12f32 AM |
113 | csd_lock_wait(csd); |
114 | csd->flags |= CSD_FLAG_LOCK; | |
8969a5ed PZ |
115 | |
116 | /* | |
0b13fda1 IM |
117 | * prevent CPU from reordering the above assignment |
118 | * to ->flags with any subsequent assignments to other | |
119 | * fields of the specified call_single_data structure: | |
8969a5ed | 120 | */ |
8053871d | 121 | smp_wmb(); |
8969a5ed PZ |
122 | } |
123 | ||
90d10984 | 124 | static __always_inline void csd_unlock(struct call_single_data *csd) |
8969a5ed | 125 | { |
8053871d | 126 | WARN_ON(!(csd->flags & CSD_FLAG_LOCK)); |
0b13fda1 | 127 | |
8969a5ed | 128 | /* |
0b13fda1 | 129 | * ensure we're all done before releasing data: |
8969a5ed | 130 | */ |
8053871d | 131 | smp_store_release(&csd->flags, 0); |
3d442233 JA |
132 | } |
133 | ||
8b28499a FW |
134 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); |
135 | ||
3d442233 | 136 | /* |
0b13fda1 IM |
137 | * Insert a previously allocated call_single_data element |
138 | * for execution on the given CPU. data must already have | |
139 | * ->func, ->info, and ->flags set. | |
3d442233 | 140 | */ |
8b28499a | 141 | static int generic_exec_single(int cpu, struct call_single_data *csd, |
8053871d | 142 | smp_call_func_t func, void *info) |
3d442233 | 143 | { |
8b28499a | 144 | if (cpu == smp_processor_id()) { |
8053871d LT |
145 | unsigned long flags; |
146 | ||
147 | /* | |
148 | * We can unlock early even for the synchronous on-stack case, | |
149 | * since we're doing this from the same CPU.. | |
150 | */ | |
151 | csd_unlock(csd); | |
8b28499a FW |
152 | local_irq_save(flags); |
153 | func(info); | |
154 | local_irq_restore(flags); | |
155 | return 0; | |
156 | } | |
157 | ||
158 | ||
5224b961 LT |
159 | if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) { |
160 | csd_unlock(csd); | |
8b28499a | 161 | return -ENXIO; |
5224b961 | 162 | } |
8b28499a | 163 | |
8b28499a FW |
164 | csd->func = func; |
165 | csd->info = info; | |
166 | ||
561920a0 | 167 | /* |
15d0d3b3 NP |
168 | * The list addition should be visible before sending the IPI |
169 | * handler locks the list to pull the entry off it because of | |
170 | * normal cache coherency rules implied by spinlocks. | |
171 | * | |
172 | * If IPIs can go out of order to the cache coherency protocol | |
173 | * in an architecture, sufficient synchronisation should be added | |
174 | * to arch code to make it appear to obey cache coherency WRT | |
0b13fda1 IM |
175 | * locking and barrier primitives. Generic code isn't really |
176 | * equipped to do the right thing... | |
561920a0 | 177 | */ |
6897fc22 | 178 | if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu))) |
3d442233 JA |
179 | arch_send_call_function_single_ipi(cpu); |
180 | ||
8b28499a | 181 | return 0; |
3d442233 JA |
182 | } |
183 | ||
8d056c48 SB |
184 | /** |
185 | * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks | |
186 | * | |
187 | * Invoked by arch to handle an IPI for call function single. | |
188 | * Must be called with interrupts disabled. | |
3d442233 JA |
189 | */ |
190 | void generic_smp_call_function_single_interrupt(void) | |
191 | { | |
8d056c48 SB |
192 | flush_smp_call_function_queue(true); |
193 | } | |
194 | ||
195 | /** | |
196 | * flush_smp_call_function_queue - Flush pending smp-call-function callbacks | |
197 | * | |
198 | * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an | |
199 | * offline CPU. Skip this check if set to 'false'. | |
200 | * | |
201 | * Flush any pending smp-call-function callbacks queued on this CPU. This is | |
202 | * invoked by the generic IPI handler, as well as by a CPU about to go offline, | |
203 | * to ensure that all pending IPI callbacks are run before it goes completely | |
204 | * offline. | |
205 | * | |
206 | * Loop through the call_single_queue and run all the queued callbacks. | |
207 | * Must be called with interrupts disabled. | |
208 | */ | |
209 | static void flush_smp_call_function_queue(bool warn_cpu_offline) | |
210 | { | |
211 | struct llist_head *head; | |
5fd77595 JK |
212 | struct llist_node *entry; |
213 | struct call_single_data *csd, *csd_next; | |
a219ccf4 SB |
214 | static bool warned; |
215 | ||
8d056c48 SB |
216 | WARN_ON(!irqs_disabled()); |
217 | ||
bb964a92 | 218 | head = this_cpu_ptr(&call_single_queue); |
8d056c48 | 219 | entry = llist_del_all(head); |
a219ccf4 | 220 | entry = llist_reverse_order(entry); |
3d442233 | 221 | |
8d056c48 SB |
222 | /* There shouldn't be any pending callbacks on an offline CPU. */ |
223 | if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) && | |
224 | !warned && !llist_empty(head))) { | |
a219ccf4 SB |
225 | warned = true; |
226 | WARN(1, "IPI on offline CPU %d\n", smp_processor_id()); | |
227 | ||
228 | /* | |
229 | * We don't have to use the _safe() variant here | |
230 | * because we are not invoking the IPI handlers yet. | |
231 | */ | |
232 | llist_for_each_entry(csd, entry, llist) | |
233 | pr_warn("IPI callback %pS sent to offline CPU\n", | |
234 | csd->func); | |
235 | } | |
3d442233 | 236 | |
5fd77595 | 237 | llist_for_each_entry_safe(csd, csd_next, entry, llist) { |
8053871d LT |
238 | smp_call_func_t func = csd->func; |
239 | void *info = csd->info; | |
240 | ||
241 | /* Do we wait until *after* callback? */ | |
242 | if (csd->flags & CSD_FLAG_SYNCHRONOUS) { | |
243 | func(info); | |
244 | csd_unlock(csd); | |
245 | } else { | |
246 | csd_unlock(csd); | |
247 | func(info); | |
248 | } | |
3d442233 | 249 | } |
47885016 FW |
250 | |
251 | /* | |
252 | * Handle irq works queued remotely by irq_work_queue_on(). | |
253 | * Smp functions above are typically synchronous so they | |
254 | * better run first since some other CPUs may be busy waiting | |
255 | * for them. | |
256 | */ | |
257 | irq_work_run(); | |
3d442233 JA |
258 | } |
259 | ||
260 | /* | |
261 | * smp_call_function_single - Run a function on a specific CPU | |
262 | * @func: The function to run. This must be fast and non-blocking. | |
263 | * @info: An arbitrary pointer to pass to the function. | |
3d442233 JA |
264 | * @wait: If true, wait until function has completed on other CPUs. |
265 | * | |
72f279b2 | 266 | * Returns 0 on success, else a negative status code. |
3d442233 | 267 | */ |
3a5f65df | 268 | int smp_call_function_single(int cpu, smp_call_func_t func, void *info, |
8691e5a8 | 269 | int wait) |
3d442233 | 270 | { |
8053871d LT |
271 | struct call_single_data *csd; |
272 | struct call_single_data csd_stack = { .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS }; | |
0b13fda1 | 273 | int this_cpu; |
8b28499a | 274 | int err; |
3d442233 | 275 | |
0b13fda1 IM |
276 | /* |
277 | * prevent preemption and reschedule on another processor, | |
278 | * as well as CPU removal | |
279 | */ | |
280 | this_cpu = get_cpu(); | |
281 | ||
269c861b SS |
282 | /* |
283 | * Can deadlock when called with interrupts disabled. | |
284 | * We allow cpu's that are not yet online though, as no one else can | |
285 | * send smp call function interrupt to this cpu and as such deadlocks | |
286 | * can't happen. | |
287 | */ | |
288 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
289 | && !oops_in_progress); | |
3d442233 | 290 | |
8053871d LT |
291 | csd = &csd_stack; |
292 | if (!wait) { | |
293 | csd = this_cpu_ptr(&csd_data); | |
294 | csd_lock(csd); | |
295 | } | |
296 | ||
297 | err = generic_exec_single(cpu, csd, func, info); | |
298 | ||
299 | if (wait) | |
300 | csd_lock_wait(csd); | |
3d442233 JA |
301 | |
302 | put_cpu(); | |
0b13fda1 | 303 | |
f73be6de | 304 | return err; |
3d442233 JA |
305 | } |
306 | EXPORT_SYMBOL(smp_call_function_single); | |
307 | ||
d7877c03 | 308 | /** |
c46fff2a FW |
309 | * smp_call_function_single_async(): Run an asynchronous function on a |
310 | * specific CPU. | |
d7877c03 FW |
311 | * @cpu: The CPU to run on. |
312 | * @csd: Pre-allocated and setup data structure | |
d7877c03 | 313 | * |
c46fff2a FW |
314 | * Like smp_call_function_single(), but the call is asynchonous and |
315 | * can thus be done from contexts with disabled interrupts. | |
316 | * | |
317 | * The caller passes his own pre-allocated data structure | |
318 | * (ie: embedded in an object) and is responsible for synchronizing it | |
319 | * such that the IPIs performed on the @csd are strictly serialized. | |
320 | * | |
321 | * NOTE: Be careful, there is unfortunately no current debugging facility to | |
322 | * validate the correctness of this serialization. | |
d7877c03 | 323 | */ |
c46fff2a | 324 | int smp_call_function_single_async(int cpu, struct call_single_data *csd) |
d7877c03 FW |
325 | { |
326 | int err = 0; | |
d7877c03 | 327 | |
fce8ad15 | 328 | preempt_disable(); |
8053871d LT |
329 | |
330 | /* We could deadlock if we have to wait here with interrupts disabled! */ | |
331 | if (WARN_ON_ONCE(csd->flags & CSD_FLAG_LOCK)) | |
332 | csd_lock_wait(csd); | |
333 | ||
334 | csd->flags = CSD_FLAG_LOCK; | |
335 | smp_wmb(); | |
336 | ||
337 | err = generic_exec_single(cpu, csd, csd->func, csd->info); | |
fce8ad15 | 338 | preempt_enable(); |
d7877c03 FW |
339 | |
340 | return err; | |
341 | } | |
c46fff2a | 342 | EXPORT_SYMBOL_GPL(smp_call_function_single_async); |
d7877c03 | 343 | |
2ea6dec4 RR |
344 | /* |
345 | * smp_call_function_any - Run a function on any of the given cpus | |
346 | * @mask: The mask of cpus it can run on. | |
347 | * @func: The function to run. This must be fast and non-blocking. | |
348 | * @info: An arbitrary pointer to pass to the function. | |
349 | * @wait: If true, wait until function has completed. | |
350 | * | |
351 | * Returns 0 on success, else a negative status code (if no cpus were online). | |
2ea6dec4 RR |
352 | * |
353 | * Selection preference: | |
354 | * 1) current cpu if in @mask | |
355 | * 2) any cpu of current node if in @mask | |
356 | * 3) any other online cpu in @mask | |
357 | */ | |
358 | int smp_call_function_any(const struct cpumask *mask, | |
3a5f65df | 359 | smp_call_func_t func, void *info, int wait) |
2ea6dec4 RR |
360 | { |
361 | unsigned int cpu; | |
362 | const struct cpumask *nodemask; | |
363 | int ret; | |
364 | ||
365 | /* Try for same CPU (cheapest) */ | |
366 | cpu = get_cpu(); | |
367 | if (cpumask_test_cpu(cpu, mask)) | |
368 | goto call; | |
369 | ||
370 | /* Try for same node. */ | |
af2422c4 | 371 | nodemask = cpumask_of_node(cpu_to_node(cpu)); |
2ea6dec4 RR |
372 | for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; |
373 | cpu = cpumask_next_and(cpu, nodemask, mask)) { | |
374 | if (cpu_online(cpu)) | |
375 | goto call; | |
376 | } | |
377 | ||
378 | /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ | |
379 | cpu = cpumask_any_and(mask, cpu_online_mask); | |
380 | call: | |
381 | ret = smp_call_function_single(cpu, func, info, wait); | |
382 | put_cpu(); | |
383 | return ret; | |
384 | } | |
385 | EXPORT_SYMBOL_GPL(smp_call_function_any); | |
386 | ||
3d442233 | 387 | /** |
54b11e6d RR |
388 | * smp_call_function_many(): Run a function on a set of other CPUs. |
389 | * @mask: The set of cpus to run on (only runs on online subset). | |
3d442233 JA |
390 | * @func: The function to run. This must be fast and non-blocking. |
391 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
392 | * @wait: If true, wait (atomically) until function has completed |
393 | * on other CPUs. | |
3d442233 | 394 | * |
72f279b2 | 395 | * If @wait is true, then returns once @func has returned. |
3d442233 JA |
396 | * |
397 | * You must not call this function with disabled interrupts or from a | |
398 | * hardware interrupt handler or from a bottom half handler. Preemption | |
399 | * must be disabled when calling this function. | |
400 | */ | |
54b11e6d | 401 | void smp_call_function_many(const struct cpumask *mask, |
3a5f65df | 402 | smp_call_func_t func, void *info, bool wait) |
3d442233 | 403 | { |
e1d12f32 | 404 | struct call_function_data *cfd; |
9a46ad6d | 405 | int cpu, next_cpu, this_cpu = smp_processor_id(); |
3d442233 | 406 | |
269c861b SS |
407 | /* |
408 | * Can deadlock when called with interrupts disabled. | |
409 | * We allow cpu's that are not yet online though, as no one else can | |
410 | * send smp call function interrupt to this cpu and as such deadlocks | |
411 | * can't happen. | |
412 | */ | |
413 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
bd924e8c | 414 | && !oops_in_progress && !early_boot_irqs_disabled); |
3d442233 | 415 | |
723aae25 | 416 | /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */ |
54b11e6d | 417 | cpu = cpumask_first_and(mask, cpu_online_mask); |
0b13fda1 | 418 | if (cpu == this_cpu) |
54b11e6d | 419 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
0b13fda1 | 420 | |
54b11e6d RR |
421 | /* No online cpus? We're done. */ |
422 | if (cpu >= nr_cpu_ids) | |
423 | return; | |
424 | ||
425 | /* Do we have another CPU which isn't us? */ | |
426 | next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask); | |
0b13fda1 | 427 | if (next_cpu == this_cpu) |
54b11e6d RR |
428 | next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask); |
429 | ||
430 | /* Fastpath: do that cpu by itself. */ | |
431 | if (next_cpu >= nr_cpu_ids) { | |
432 | smp_call_function_single(cpu, func, info, wait); | |
433 | return; | |
3d442233 JA |
434 | } |
435 | ||
bb964a92 | 436 | cfd = this_cpu_ptr(&cfd_data); |
45a57919 | 437 | |
e1d12f32 | 438 | cpumask_and(cfd->cpumask, mask, cpu_online_mask); |
6c8557bd | 439 | __cpumask_clear_cpu(this_cpu, cfd->cpumask); |
723aae25 MM |
440 | |
441 | /* Some callers race with other cpus changing the passed mask */ | |
e1d12f32 | 442 | if (unlikely(!cpumask_weight(cfd->cpumask))) |
723aae25 | 443 | return; |
3d442233 | 444 | |
3fc5b3b6 | 445 | cpumask_clear(cfd->cpumask_ipi); |
e1d12f32 AM |
446 | for_each_cpu(cpu, cfd->cpumask) { |
447 | struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu); | |
9a46ad6d SL |
448 | |
449 | csd_lock(csd); | |
8053871d LT |
450 | if (wait) |
451 | csd->flags |= CSD_FLAG_SYNCHRONOUS; | |
9a46ad6d SL |
452 | csd->func = func; |
453 | csd->info = info; | |
3fc5b3b6 | 454 | if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu))) |
6c8557bd | 455 | __cpumask_set_cpu(cpu, cfd->cpumask_ipi); |
9a46ad6d | 456 | } |
561920a0 | 457 | |
3d442233 | 458 | /* Send a message to all CPUs in the map */ |
3fc5b3b6 | 459 | arch_send_call_function_ipi_mask(cfd->cpumask_ipi); |
3d442233 | 460 | |
9a46ad6d | 461 | if (wait) { |
e1d12f32 AM |
462 | for_each_cpu(cpu, cfd->cpumask) { |
463 | struct call_single_data *csd; | |
464 | ||
465 | csd = per_cpu_ptr(cfd->csd, cpu); | |
9a46ad6d SL |
466 | csd_lock_wait(csd); |
467 | } | |
468 | } | |
3d442233 | 469 | } |
54b11e6d | 470 | EXPORT_SYMBOL(smp_call_function_many); |
3d442233 JA |
471 | |
472 | /** | |
473 | * smp_call_function(): Run a function on all other CPUs. | |
474 | * @func: The function to run. This must be fast and non-blocking. | |
475 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
476 | * @wait: If true, wait (atomically) until function has completed |
477 | * on other CPUs. | |
3d442233 | 478 | * |
54b11e6d | 479 | * Returns 0. |
3d442233 JA |
480 | * |
481 | * If @wait is true, then returns once @func has returned; otherwise | |
72f279b2 | 482 | * it returns just before the target cpu calls @func. |
3d442233 JA |
483 | * |
484 | * You must not call this function with disabled interrupts or from a | |
485 | * hardware interrupt handler or from a bottom half handler. | |
486 | */ | |
3a5f65df | 487 | int smp_call_function(smp_call_func_t func, void *info, int wait) |
3d442233 | 488 | { |
3d442233 | 489 | preempt_disable(); |
54b11e6d | 490 | smp_call_function_many(cpu_online_mask, func, info, wait); |
3d442233 | 491 | preempt_enable(); |
0b13fda1 | 492 | |
54b11e6d | 493 | return 0; |
3d442233 JA |
494 | } |
495 | EXPORT_SYMBOL(smp_call_function); | |
351f8f8e | 496 | |
34db18a0 AW |
497 | /* Setup configured maximum number of CPUs to activate */ |
498 | unsigned int setup_max_cpus = NR_CPUS; | |
499 | EXPORT_SYMBOL(setup_max_cpus); | |
500 | ||
501 | ||
502 | /* | |
503 | * Setup routine for controlling SMP activation | |
504 | * | |
505 | * Command-line option of "nosmp" or "maxcpus=0" will disable SMP | |
506 | * activation entirely (the MPS table probe still happens, though). | |
507 | * | |
508 | * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer | |
509 | * greater than 0, limits the maximum number of CPUs activated in | |
510 | * SMP mode to <NUM>. | |
511 | */ | |
512 | ||
513 | void __weak arch_disable_smp_support(void) { } | |
514 | ||
515 | static int __init nosmp(char *str) | |
516 | { | |
517 | setup_max_cpus = 0; | |
518 | arch_disable_smp_support(); | |
519 | ||
520 | return 0; | |
521 | } | |
522 | ||
523 | early_param("nosmp", nosmp); | |
524 | ||
525 | /* this is hard limit */ | |
526 | static int __init nrcpus(char *str) | |
527 | { | |
528 | int nr_cpus; | |
529 | ||
530 | get_option(&str, &nr_cpus); | |
531 | if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) | |
532 | nr_cpu_ids = nr_cpus; | |
533 | ||
534 | return 0; | |
535 | } | |
536 | ||
537 | early_param("nr_cpus", nrcpus); | |
538 | ||
539 | static int __init maxcpus(char *str) | |
540 | { | |
541 | get_option(&str, &setup_max_cpus); | |
542 | if (setup_max_cpus == 0) | |
543 | arch_disable_smp_support(); | |
544 | ||
545 | return 0; | |
546 | } | |
547 | ||
548 | early_param("maxcpus", maxcpus); | |
549 | ||
550 | /* Setup number of possible processor ids */ | |
551 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
552 | EXPORT_SYMBOL(nr_cpu_ids); | |
553 | ||
554 | /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ | |
555 | void __init setup_nr_cpu_ids(void) | |
556 | { | |
557 | nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; | |
558 | } | |
559 | ||
560 | /* Called by boot processor to activate the rest. */ | |
561 | void __init smp_init(void) | |
562 | { | |
92b23278 | 563 | int num_nodes, num_cpus; |
34db18a0 AW |
564 | unsigned int cpu; |
565 | ||
3bb5d2ee | 566 | idle_threads_init(); |
4cb28ced | 567 | cpuhp_threads_init(); |
3bb5d2ee | 568 | |
51111dce ME |
569 | pr_info("Bringing up secondary CPUs ...\n"); |
570 | ||
34db18a0 AW |
571 | /* FIXME: This should be done in userspace --RR */ |
572 | for_each_present_cpu(cpu) { | |
573 | if (num_online_cpus() >= setup_max_cpus) | |
574 | break; | |
575 | if (!cpu_online(cpu)) | |
576 | cpu_up(cpu); | |
577 | } | |
578 | ||
92b23278 ME |
579 | num_nodes = num_online_nodes(); |
580 | num_cpus = num_online_cpus(); | |
581 | pr_info("Brought up %d node%s, %d CPU%s\n", | |
582 | num_nodes, (num_nodes > 1 ? "s" : ""), | |
583 | num_cpus, (num_cpus > 1 ? "s" : "")); | |
584 | ||
34db18a0 | 585 | /* Any cleanup work */ |
34db18a0 AW |
586 | smp_cpus_done(setup_max_cpus); |
587 | } | |
588 | ||
351f8f8e | 589 | /* |
bd924e8c TH |
590 | * Call a function on all processors. May be used during early boot while |
591 | * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead | |
592 | * of local_irq_disable/enable(). | |
351f8f8e AW |
593 | */ |
594 | int on_each_cpu(void (*func) (void *info), void *info, int wait) | |
595 | { | |
bd924e8c | 596 | unsigned long flags; |
351f8f8e AW |
597 | int ret = 0; |
598 | ||
599 | preempt_disable(); | |
600 | ret = smp_call_function(func, info, wait); | |
bd924e8c | 601 | local_irq_save(flags); |
351f8f8e | 602 | func(info); |
bd924e8c | 603 | local_irq_restore(flags); |
351f8f8e AW |
604 | preempt_enable(); |
605 | return ret; | |
606 | } | |
607 | EXPORT_SYMBOL(on_each_cpu); | |
3fc498f1 GBY |
608 | |
609 | /** | |
610 | * on_each_cpu_mask(): Run a function on processors specified by | |
611 | * cpumask, which may include the local processor. | |
612 | * @mask: The set of cpus to run on (only runs on online subset). | |
613 | * @func: The function to run. This must be fast and non-blocking. | |
614 | * @info: An arbitrary pointer to pass to the function. | |
615 | * @wait: If true, wait (atomically) until function has completed | |
616 | * on other CPUs. | |
617 | * | |
618 | * If @wait is true, then returns once @func has returned. | |
619 | * | |
202da400 DD |
620 | * You must not call this function with disabled interrupts or from a |
621 | * hardware interrupt handler or from a bottom half handler. The | |
622 | * exception is that it may be used during early boot while | |
623 | * early_boot_irqs_disabled is set. | |
3fc498f1 GBY |
624 | */ |
625 | void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, | |
626 | void *info, bool wait) | |
627 | { | |
628 | int cpu = get_cpu(); | |
629 | ||
630 | smp_call_function_many(mask, func, info, wait); | |
631 | if (cpumask_test_cpu(cpu, mask)) { | |
202da400 DD |
632 | unsigned long flags; |
633 | local_irq_save(flags); | |
3fc498f1 | 634 | func(info); |
202da400 | 635 | local_irq_restore(flags); |
3fc498f1 GBY |
636 | } |
637 | put_cpu(); | |
638 | } | |
639 | EXPORT_SYMBOL(on_each_cpu_mask); | |
b3a7e98e GBY |
640 | |
641 | /* | |
642 | * on_each_cpu_cond(): Call a function on each processor for which | |
643 | * the supplied function cond_func returns true, optionally waiting | |
644 | * for all the required CPUs to finish. This may include the local | |
645 | * processor. | |
646 | * @cond_func: A callback function that is passed a cpu id and | |
647 | * the the info parameter. The function is called | |
648 | * with preemption disabled. The function should | |
649 | * return a blooean value indicating whether to IPI | |
650 | * the specified CPU. | |
651 | * @func: The function to run on all applicable CPUs. | |
652 | * This must be fast and non-blocking. | |
653 | * @info: An arbitrary pointer to pass to both functions. | |
654 | * @wait: If true, wait (atomically) until function has | |
655 | * completed on other CPUs. | |
656 | * @gfp_flags: GFP flags to use when allocating the cpumask | |
657 | * used internally by the function. | |
658 | * | |
659 | * The function might sleep if the GFP flags indicates a non | |
660 | * atomic allocation is allowed. | |
661 | * | |
662 | * Preemption is disabled to protect against CPUs going offline but not online. | |
663 | * CPUs going online during the call will not be seen or sent an IPI. | |
664 | * | |
665 | * You must not call this function with disabled interrupts or | |
666 | * from a hardware interrupt handler or from a bottom half handler. | |
667 | */ | |
668 | void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), | |
669 | smp_call_func_t func, void *info, bool wait, | |
670 | gfp_t gfp_flags) | |
671 | { | |
672 | cpumask_var_t cpus; | |
673 | int cpu, ret; | |
674 | ||
d0164adc | 675 | might_sleep_if(gfpflags_allow_blocking(gfp_flags)); |
b3a7e98e GBY |
676 | |
677 | if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) { | |
678 | preempt_disable(); | |
679 | for_each_online_cpu(cpu) | |
680 | if (cond_func(cpu, info)) | |
681 | cpumask_set_cpu(cpu, cpus); | |
682 | on_each_cpu_mask(cpus, func, info, wait); | |
683 | preempt_enable(); | |
684 | free_cpumask_var(cpus); | |
685 | } else { | |
686 | /* | |
687 | * No free cpumask, bother. No matter, we'll | |
688 | * just have to IPI them one by one. | |
689 | */ | |
690 | preempt_disable(); | |
691 | for_each_online_cpu(cpu) | |
692 | if (cond_func(cpu, info)) { | |
693 | ret = smp_call_function_single(cpu, func, | |
694 | info, wait); | |
618fde87 | 695 | WARN_ON_ONCE(ret); |
b3a7e98e GBY |
696 | } |
697 | preempt_enable(); | |
698 | } | |
699 | } | |
700 | EXPORT_SYMBOL(on_each_cpu_cond); | |
f37f435f TG |
701 | |
702 | static void do_nothing(void *unused) | |
703 | { | |
704 | } | |
705 | ||
706 | /** | |
707 | * kick_all_cpus_sync - Force all cpus out of idle | |
708 | * | |
709 | * Used to synchronize the update of pm_idle function pointer. It's | |
710 | * called after the pointer is updated and returns after the dummy | |
711 | * callback function has been executed on all cpus. The execution of | |
712 | * the function can only happen on the remote cpus after they have | |
713 | * left the idle function which had been called via pm_idle function | |
714 | * pointer. So it's guaranteed that nothing uses the previous pointer | |
715 | * anymore. | |
716 | */ | |
717 | void kick_all_cpus_sync(void) | |
718 | { | |
719 | /* Make sure the change is visible before we kick the cpus */ | |
720 | smp_mb(); | |
721 | smp_call_function(do_nothing, NULL, 1); | |
722 | } | |
723 | EXPORT_SYMBOL_GPL(kick_all_cpus_sync); | |
c6f4459f CL |
724 | |
725 | /** | |
726 | * wake_up_all_idle_cpus - break all cpus out of idle | |
727 | * wake_up_all_idle_cpus try to break all cpus which is in idle state even | |
728 | * including idle polling cpus, for non-idle cpus, we will do nothing | |
729 | * for them. | |
730 | */ | |
731 | void wake_up_all_idle_cpus(void) | |
732 | { | |
733 | int cpu; | |
734 | ||
735 | preempt_disable(); | |
736 | for_each_online_cpu(cpu) { | |
737 | if (cpu == smp_processor_id()) | |
738 | continue; | |
739 | ||
740 | wake_up_if_idle(cpu); | |
741 | } | |
742 | preempt_enable(); | |
743 | } | |
744 | EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); | |
df8ce9d7 JG |
745 | |
746 | /** | |
747 | * smp_call_on_cpu - Call a function on a specific cpu | |
748 | * | |
749 | * Used to call a function on a specific cpu and wait for it to return. | |
750 | * Optionally make sure the call is done on a specified physical cpu via vcpu | |
751 | * pinning in order to support virtualized environments. | |
752 | */ | |
753 | struct smp_call_on_cpu_struct { | |
754 | struct work_struct work; | |
755 | struct completion done; | |
756 | int (*func)(void *); | |
757 | void *data; | |
758 | int ret; | |
759 | int cpu; | |
760 | }; | |
761 | ||
762 | static void smp_call_on_cpu_callback(struct work_struct *work) | |
763 | { | |
764 | struct smp_call_on_cpu_struct *sscs; | |
765 | ||
766 | sscs = container_of(work, struct smp_call_on_cpu_struct, work); | |
767 | if (sscs->cpu >= 0) | |
768 | hypervisor_pin_vcpu(sscs->cpu); | |
769 | sscs->ret = sscs->func(sscs->data); | |
770 | if (sscs->cpu >= 0) | |
771 | hypervisor_pin_vcpu(-1); | |
772 | ||
773 | complete(&sscs->done); | |
774 | } | |
775 | ||
776 | int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) | |
777 | { | |
778 | struct smp_call_on_cpu_struct sscs = { | |
df8ce9d7 JG |
779 | .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), |
780 | .func = func, | |
781 | .data = par, | |
782 | .cpu = phys ? cpu : -1, | |
783 | }; | |
784 | ||
8db54949 PZ |
785 | INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback); |
786 | ||
df8ce9d7 JG |
787 | if (cpu >= nr_cpu_ids || !cpu_online(cpu)) |
788 | return -ENXIO; | |
789 | ||
790 | queue_work_on(cpu, system_wq, &sscs.work); | |
791 | wait_for_completion(&sscs.done); | |
792 | ||
793 | return sscs.ret; | |
794 | } | |
795 | EXPORT_SYMBOL_GPL(smp_call_on_cpu); |