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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3d442233 JA |
2 | /* |
3 | * Generic helpers for smp ipi calls | |
4 | * | |
5 | * (C) Jens Axboe <jens.axboe@oracle.com> 2008 | |
3d442233 | 6 | */ |
ca7dfdbb ME |
7 | |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
9 | ||
47885016 | 10 | #include <linux/irq_work.h> |
3d442233 | 11 | #include <linux/rcupdate.h> |
59190f42 | 12 | #include <linux/rculist.h> |
641cd4cf | 13 | #include <linux/kernel.h> |
9984de1a | 14 | #include <linux/export.h> |
0b13fda1 IM |
15 | #include <linux/percpu.h> |
16 | #include <linux/init.h> | |
f9d34595 | 17 | #include <linux/interrupt.h> |
5a0e3ad6 | 18 | #include <linux/gfp.h> |
3d442233 | 19 | #include <linux/smp.h> |
8969a5ed | 20 | #include <linux/cpu.h> |
c6f4459f | 21 | #include <linux/sched.h> |
4c822698 | 22 | #include <linux/sched/idle.h> |
47ae4b05 | 23 | #include <linux/hypervisor.h> |
35feb604 PM |
24 | #include <linux/sched/clock.h> |
25 | #include <linux/nmi.h> | |
26 | #include <linux/sched/debug.h> | |
8d0968cc | 27 | #include <linux/jump_label.h> |
3d442233 | 28 | |
3bb5d2ee | 29 | #include "smpboot.h" |
1f8db415 | 30 | #include "sched/smp.h" |
3bb5d2ee | 31 | |
545b8c8d | 32 | #define CSD_TYPE(_csd) ((_csd)->node.u_flags & CSD_FLAG_TYPE_MASK) |
3d442233 | 33 | |
de7b09ef JG |
34 | struct cfd_percpu { |
35 | call_single_data_t csd; | |
36 | }; | |
37 | ||
3d442233 | 38 | struct call_function_data { |
de7b09ef | 39 | struct cfd_percpu __percpu *pcpu; |
0b13fda1 | 40 | cpumask_var_t cpumask; |
3fc5b3b6 | 41 | cpumask_var_t cpumask_ipi; |
3d442233 JA |
42 | }; |
43 | ||
a22793c7 | 44 | static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data); |
e03bcb68 | 45 | |
6897fc22 | 46 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); |
8969a5ed | 47 | |
8d056c48 SB |
48 | static void flush_smp_call_function_queue(bool warn_cpu_offline); |
49 | ||
31487f83 | 50 | int smpcfd_prepare_cpu(unsigned int cpu) |
8969a5ed | 51 | { |
8969a5ed PZ |
52 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); |
53 | ||
31487f83 RW |
54 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, |
55 | cpu_to_node(cpu))) | |
56 | return -ENOMEM; | |
3fc5b3b6 AL |
57 | if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL, |
58 | cpu_to_node(cpu))) { | |
59 | free_cpumask_var(cfd->cpumask); | |
60 | return -ENOMEM; | |
61 | } | |
de7b09ef JG |
62 | cfd->pcpu = alloc_percpu(struct cfd_percpu); |
63 | if (!cfd->pcpu) { | |
8969a5ed | 64 | free_cpumask_var(cfd->cpumask); |
3fc5b3b6 | 65 | free_cpumask_var(cfd->cpumask_ipi); |
31487f83 RW |
66 | return -ENOMEM; |
67 | } | |
68 | ||
69 | return 0; | |
8969a5ed PZ |
70 | } |
71 | ||
31487f83 RW |
72 | int smpcfd_dead_cpu(unsigned int cpu) |
73 | { | |
74 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); | |
75 | ||
76 | free_cpumask_var(cfd->cpumask); | |
3fc5b3b6 | 77 | free_cpumask_var(cfd->cpumask_ipi); |
de7b09ef | 78 | free_percpu(cfd->pcpu); |
31487f83 RW |
79 | return 0; |
80 | } | |
81 | ||
82 | int smpcfd_dying_cpu(unsigned int cpu) | |
83 | { | |
84 | /* | |
85 | * The IPIs for the smp-call-function callbacks queued by other | |
86 | * CPUs might arrive late, either due to hardware latencies or | |
87 | * because this CPU disabled interrupts (inside stop-machine) | |
88 | * before the IPIs were sent. So flush out any pending callbacks | |
89 | * explicitly (without waiting for the IPIs to arrive), to | |
90 | * ensure that the outgoing CPU doesn't go offline with work | |
91 | * still pending. | |
92 | */ | |
93 | flush_smp_call_function_queue(false); | |
afaa653c | 94 | irq_work_run(); |
31487f83 RW |
95 | return 0; |
96 | } | |
8969a5ed | 97 | |
d8ad7d11 | 98 | void __init call_function_init(void) |
3d442233 JA |
99 | { |
100 | int i; | |
101 | ||
6897fc22 CH |
102 | for_each_possible_cpu(i) |
103 | init_llist_head(&per_cpu(call_single_queue, i)); | |
8969a5ed | 104 | |
31487f83 | 105 | smpcfd_prepare_cpu(smp_processor_id()); |
3d442233 JA |
106 | } |
107 | ||
35feb604 PM |
108 | #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG |
109 | ||
8d0968cc JG |
110 | static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled); |
111 | ||
112 | static int __init csdlock_debug(char *str) | |
113 | { | |
114 | unsigned int val = 0; | |
115 | ||
116 | get_option(&str, &val); | |
117 | if (val) | |
118 | static_branch_enable(&csdlock_debug_enabled); | |
119 | ||
120 | return 0; | |
121 | } | |
122 | early_param("csdlock_debug", csdlock_debug); | |
123 | ||
35feb604 PM |
124 | static DEFINE_PER_CPU(call_single_data_t *, cur_csd); |
125 | static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func); | |
126 | static DEFINE_PER_CPU(void *, cur_csd_info); | |
127 | ||
128 | #define CSD_LOCK_TIMEOUT (5ULL * NSEC_PER_SEC) | |
2b722160 | 129 | static atomic_t csd_bug_count = ATOMIC_INIT(0); |
35feb604 PM |
130 | |
131 | /* Record current CSD work for current CPU, NULL to erase. */ | |
8d0968cc | 132 | static void __csd_lock_record(call_single_data_t *csd) |
35feb604 PM |
133 | { |
134 | if (!csd) { | |
135 | smp_mb(); /* NULL cur_csd after unlock. */ | |
136 | __this_cpu_write(cur_csd, NULL); | |
137 | return; | |
138 | } | |
139 | __this_cpu_write(cur_csd_func, csd->func); | |
140 | __this_cpu_write(cur_csd_info, csd->info); | |
141 | smp_wmb(); /* func and info before csd. */ | |
142 | __this_cpu_write(cur_csd, csd); | |
143 | smp_mb(); /* Update cur_csd before function call. */ | |
144 | /* Or before unlock, as the case may be. */ | |
145 | } | |
146 | ||
8d0968cc JG |
147 | static __always_inline void csd_lock_record(call_single_data_t *csd) |
148 | { | |
149 | if (static_branch_unlikely(&csdlock_debug_enabled)) | |
150 | __csd_lock_record(csd); | |
151 | } | |
152 | ||
153 | static int csd_lock_wait_getcpu(call_single_data_t *csd) | |
35feb604 PM |
154 | { |
155 | unsigned int csd_type; | |
156 | ||
157 | csd_type = CSD_TYPE(csd); | |
158 | if (csd_type == CSD_TYPE_ASYNC || csd_type == CSD_TYPE_SYNC) | |
a787bdaf | 159 | return csd->node.dst; /* Other CSD_TYPE_ values might not have ->dst. */ |
35feb604 PM |
160 | return -1; |
161 | } | |
162 | ||
163 | /* | |
164 | * Complain if too much time spent waiting. Note that only | |
165 | * the CSD_TYPE_SYNC/ASYNC types provide the destination CPU, | |
166 | * so waiting on other types gets much less information. | |
167 | */ | |
8d0968cc | 168 | static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, int *bug_id) |
35feb604 PM |
169 | { |
170 | int cpu = -1; | |
171 | int cpux; | |
172 | bool firsttime; | |
173 | u64 ts2, ts_delta; | |
174 | call_single_data_t *cpu_cur_csd; | |
545b8c8d | 175 | unsigned int flags = READ_ONCE(csd->node.u_flags); |
35feb604 PM |
176 | |
177 | if (!(flags & CSD_FLAG_LOCK)) { | |
178 | if (!unlikely(*bug_id)) | |
179 | return true; | |
180 | cpu = csd_lock_wait_getcpu(csd); | |
181 | pr_alert("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock.\n", | |
182 | *bug_id, raw_smp_processor_id(), cpu); | |
183 | return true; | |
184 | } | |
185 | ||
186 | ts2 = sched_clock(); | |
187 | ts_delta = ts2 - *ts1; | |
188 | if (likely(ts_delta <= CSD_LOCK_TIMEOUT)) | |
189 | return false; | |
190 | ||
191 | firsttime = !*bug_id; | |
192 | if (firsttime) | |
193 | *bug_id = atomic_inc_return(&csd_bug_count); | |
194 | cpu = csd_lock_wait_getcpu(csd); | |
195 | if (WARN_ONCE(cpu < 0 || cpu >= nr_cpu_ids, "%s: cpu = %d\n", __func__, cpu)) | |
196 | cpux = 0; | |
197 | else | |
198 | cpux = cpu; | |
199 | cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */ | |
200 | pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n", | |
201 | firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts2 - ts0, | |
202 | cpu, csd->func, csd->info); | |
203 | if (cpu_cur_csd && csd != cpu_cur_csd) { | |
204 | pr_alert("\tcsd: CSD lock (#%d) handling prior %pS(%ps) request.\n", | |
205 | *bug_id, READ_ONCE(per_cpu(cur_csd_func, cpux)), | |
206 | READ_ONCE(per_cpu(cur_csd_info, cpux))); | |
207 | } else { | |
208 | pr_alert("\tcsd: CSD lock (#%d) %s.\n", | |
209 | *bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request"); | |
210 | } | |
211 | if (cpu >= 0) { | |
212 | if (!trigger_single_cpu_backtrace(cpu)) | |
213 | dump_cpu_task(cpu); | |
214 | if (!cpu_cur_csd) { | |
215 | pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu); | |
216 | arch_send_call_function_single_ipi(cpu); | |
217 | } | |
218 | } | |
219 | dump_stack(); | |
220 | *ts1 = ts2; | |
221 | ||
222 | return false; | |
223 | } | |
224 | ||
8969a5ed PZ |
225 | /* |
226 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources | |
227 | * | |
0b13fda1 IM |
228 | * For non-synchronous ipi calls the csd can still be in use by the |
229 | * previous function call. For multi-cpu calls its even more interesting | |
230 | * as we'll have to ensure no other cpu is observing our csd. | |
8969a5ed | 231 | */ |
8d0968cc | 232 | static void __csd_lock_wait(call_single_data_t *csd) |
35feb604 PM |
233 | { |
234 | int bug_id = 0; | |
235 | u64 ts0, ts1; | |
236 | ||
237 | ts1 = ts0 = sched_clock(); | |
238 | for (;;) { | |
239 | if (csd_lock_wait_toolong(csd, ts0, &ts1, &bug_id)) | |
240 | break; | |
241 | cpu_relax(); | |
242 | } | |
243 | smp_acquire__after_ctrl_dep(); | |
244 | } | |
245 | ||
8d0968cc JG |
246 | static __always_inline void csd_lock_wait(call_single_data_t *csd) |
247 | { | |
248 | if (static_branch_unlikely(&csdlock_debug_enabled)) { | |
249 | __csd_lock_wait(csd); | |
250 | return; | |
251 | } | |
252 | ||
253 | smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK)); | |
254 | } | |
35feb604 PM |
255 | #else |
256 | static void csd_lock_record(call_single_data_t *csd) | |
257 | { | |
258 | } | |
259 | ||
966a9671 | 260 | static __always_inline void csd_lock_wait(call_single_data_t *csd) |
8969a5ed | 261 | { |
545b8c8d | 262 | smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK)); |
6e275637 | 263 | } |
35feb604 | 264 | #endif |
6e275637 | 265 | |
966a9671 | 266 | static __always_inline void csd_lock(call_single_data_t *csd) |
6e275637 | 267 | { |
e1d12f32 | 268 | csd_lock_wait(csd); |
545b8c8d | 269 | csd->node.u_flags |= CSD_FLAG_LOCK; |
8969a5ed PZ |
270 | |
271 | /* | |
0b13fda1 IM |
272 | * prevent CPU from reordering the above assignment |
273 | * to ->flags with any subsequent assignments to other | |
966a9671 | 274 | * fields of the specified call_single_data_t structure: |
8969a5ed | 275 | */ |
8053871d | 276 | smp_wmb(); |
8969a5ed PZ |
277 | } |
278 | ||
966a9671 | 279 | static __always_inline void csd_unlock(call_single_data_t *csd) |
8969a5ed | 280 | { |
545b8c8d | 281 | WARN_ON(!(csd->node.u_flags & CSD_FLAG_LOCK)); |
0b13fda1 | 282 | |
8969a5ed | 283 | /* |
0b13fda1 | 284 | * ensure we're all done before releasing data: |
8969a5ed | 285 | */ |
545b8c8d | 286 | smp_store_release(&csd->node.u_flags, 0); |
3d442233 JA |
287 | } |
288 | ||
966a9671 | 289 | static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data); |
8b28499a | 290 | |
4b44a21d PZ |
291 | void __smp_call_single_queue(int cpu, struct llist_node *node) |
292 | { | |
293 | /* | |
294 | * The list addition should be visible before sending the IPI | |
295 | * handler locks the list to pull the entry off it because of | |
296 | * normal cache coherency rules implied by spinlocks. | |
297 | * | |
298 | * If IPIs can go out of order to the cache coherency protocol | |
299 | * in an architecture, sufficient synchronisation should be added | |
300 | * to arch code to make it appear to obey cache coherency WRT | |
301 | * locking and barrier primitives. Generic code isn't really | |
302 | * equipped to do the right thing... | |
303 | */ | |
304 | if (llist_add(node, &per_cpu(call_single_queue, cpu))) | |
305 | send_call_function_single_ipi(cpu); | |
306 | } | |
307 | ||
3d442233 | 308 | /* |
966a9671 | 309 | * Insert a previously allocated call_single_data_t element |
0b13fda1 IM |
310 | * for execution on the given CPU. data must already have |
311 | * ->func, ->info, and ->flags set. | |
3d442233 | 312 | */ |
4b44a21d | 313 | static int generic_exec_single(int cpu, call_single_data_t *csd) |
3d442233 | 314 | { |
8b28499a | 315 | if (cpu == smp_processor_id()) { |
4b44a21d PZ |
316 | smp_call_func_t func = csd->func; |
317 | void *info = csd->info; | |
8053871d LT |
318 | unsigned long flags; |
319 | ||
320 | /* | |
321 | * We can unlock early even for the synchronous on-stack case, | |
322 | * since we're doing this from the same CPU.. | |
323 | */ | |
35feb604 | 324 | csd_lock_record(csd); |
8053871d | 325 | csd_unlock(csd); |
8b28499a FW |
326 | local_irq_save(flags); |
327 | func(info); | |
35feb604 | 328 | csd_lock_record(NULL); |
8b28499a FW |
329 | local_irq_restore(flags); |
330 | return 0; | |
331 | } | |
332 | ||
5224b961 LT |
333 | if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) { |
334 | csd_unlock(csd); | |
8b28499a | 335 | return -ENXIO; |
5224b961 | 336 | } |
8b28499a | 337 | |
545b8c8d | 338 | __smp_call_single_queue(cpu, &csd->node.llist); |
3d442233 | 339 | |
8b28499a | 340 | return 0; |
3d442233 JA |
341 | } |
342 | ||
8d056c48 SB |
343 | /** |
344 | * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks | |
345 | * | |
346 | * Invoked by arch to handle an IPI for call function single. | |
347 | * Must be called with interrupts disabled. | |
3d442233 JA |
348 | */ |
349 | void generic_smp_call_function_single_interrupt(void) | |
350 | { | |
8d056c48 SB |
351 | flush_smp_call_function_queue(true); |
352 | } | |
353 | ||
354 | /** | |
355 | * flush_smp_call_function_queue - Flush pending smp-call-function callbacks | |
356 | * | |
357 | * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an | |
358 | * offline CPU. Skip this check if set to 'false'. | |
359 | * | |
360 | * Flush any pending smp-call-function callbacks queued on this CPU. This is | |
361 | * invoked by the generic IPI handler, as well as by a CPU about to go offline, | |
362 | * to ensure that all pending IPI callbacks are run before it goes completely | |
363 | * offline. | |
364 | * | |
365 | * Loop through the call_single_queue and run all the queued callbacks. | |
366 | * Must be called with interrupts disabled. | |
367 | */ | |
368 | static void flush_smp_call_function_queue(bool warn_cpu_offline) | |
369 | { | |
966a9671 | 370 | call_single_data_t *csd, *csd_next; |
52103be0 PZ |
371 | struct llist_node *entry, *prev; |
372 | struct llist_head *head; | |
a219ccf4 SB |
373 | static bool warned; |
374 | ||
83efcbd0 | 375 | lockdep_assert_irqs_disabled(); |
8d056c48 | 376 | |
bb964a92 | 377 | head = this_cpu_ptr(&call_single_queue); |
8d056c48 | 378 | entry = llist_del_all(head); |
a219ccf4 | 379 | entry = llist_reverse_order(entry); |
3d442233 | 380 | |
8d056c48 SB |
381 | /* There shouldn't be any pending callbacks on an offline CPU. */ |
382 | if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) && | |
383 | !warned && !llist_empty(head))) { | |
a219ccf4 SB |
384 | warned = true; |
385 | WARN(1, "IPI on offline CPU %d\n", smp_processor_id()); | |
386 | ||
387 | /* | |
388 | * We don't have to use the _safe() variant here | |
389 | * because we are not invoking the IPI handlers yet. | |
390 | */ | |
545b8c8d | 391 | llist_for_each_entry(csd, entry, node.llist) { |
4b44a21d PZ |
392 | switch (CSD_TYPE(csd)) { |
393 | case CSD_TYPE_ASYNC: | |
394 | case CSD_TYPE_SYNC: | |
395 | case CSD_TYPE_IRQ_WORK: | |
396 | pr_warn("IPI callback %pS sent to offline CPU\n", | |
397 | csd->func); | |
398 | break; | |
399 | ||
a1488664 PZ |
400 | case CSD_TYPE_TTWU: |
401 | pr_warn("IPI task-wakeup sent to offline CPU\n"); | |
402 | break; | |
403 | ||
4b44a21d PZ |
404 | default: |
405 | pr_warn("IPI callback, unknown type %d, sent to offline CPU\n", | |
406 | CSD_TYPE(csd)); | |
407 | break; | |
408 | } | |
409 | } | |
a219ccf4 | 410 | } |
3d442233 | 411 | |
52103be0 PZ |
412 | /* |
413 | * First; run all SYNC callbacks, people are waiting for us. | |
414 | */ | |
415 | prev = NULL; | |
545b8c8d | 416 | llist_for_each_entry_safe(csd, csd_next, entry, node.llist) { |
8053871d | 417 | /* Do we wait until *after* callback? */ |
4b44a21d PZ |
418 | if (CSD_TYPE(csd) == CSD_TYPE_SYNC) { |
419 | smp_call_func_t func = csd->func; | |
420 | void *info = csd->info; | |
421 | ||
52103be0 | 422 | if (prev) { |
545b8c8d | 423 | prev->next = &csd_next->node.llist; |
52103be0 | 424 | } else { |
545b8c8d | 425 | entry = &csd_next->node.llist; |
52103be0 | 426 | } |
4b44a21d | 427 | |
35feb604 | 428 | csd_lock_record(csd); |
8053871d LT |
429 | func(info); |
430 | csd_unlock(csd); | |
35feb604 | 431 | csd_lock_record(NULL); |
8053871d | 432 | } else { |
545b8c8d | 433 | prev = &csd->node.llist; |
8053871d | 434 | } |
3d442233 | 435 | } |
47885016 | 436 | |
a1488664 PZ |
437 | if (!entry) |
438 | return; | |
439 | ||
47885016 | 440 | /* |
52103be0 | 441 | * Second; run all !SYNC callbacks. |
47885016 | 442 | */ |
a1488664 | 443 | prev = NULL; |
545b8c8d | 444 | llist_for_each_entry_safe(csd, csd_next, entry, node.llist) { |
4b44a21d | 445 | int type = CSD_TYPE(csd); |
52103be0 | 446 | |
a1488664 PZ |
447 | if (type != CSD_TYPE_TTWU) { |
448 | if (prev) { | |
545b8c8d | 449 | prev->next = &csd_next->node.llist; |
a1488664 | 450 | } else { |
545b8c8d | 451 | entry = &csd_next->node.llist; |
a1488664 | 452 | } |
4b44a21d | 453 | |
a1488664 PZ |
454 | if (type == CSD_TYPE_ASYNC) { |
455 | smp_call_func_t func = csd->func; | |
456 | void *info = csd->info; | |
457 | ||
35feb604 | 458 | csd_lock_record(csd); |
a1488664 PZ |
459 | csd_unlock(csd); |
460 | func(info); | |
35feb604 | 461 | csd_lock_record(NULL); |
a1488664 PZ |
462 | } else if (type == CSD_TYPE_IRQ_WORK) { |
463 | irq_work_single(csd); | |
464 | } | |
465 | ||
466 | } else { | |
545b8c8d | 467 | prev = &csd->node.llist; |
4b44a21d | 468 | } |
52103be0 | 469 | } |
a1488664 PZ |
470 | |
471 | /* | |
472 | * Third; only CSD_TYPE_TTWU is left, issue those. | |
473 | */ | |
474 | if (entry) | |
475 | sched_ttwu_pending(entry); | |
3d442233 JA |
476 | } |
477 | ||
b2a02fc4 PZ |
478 | void flush_smp_call_function_from_idle(void) |
479 | { | |
480 | unsigned long flags; | |
481 | ||
482 | if (llist_empty(this_cpu_ptr(&call_single_queue))) | |
483 | return; | |
484 | ||
485 | local_irq_save(flags); | |
486 | flush_smp_call_function_queue(true); | |
f9d34595 SAS |
487 | if (local_softirq_pending()) |
488 | do_softirq(); | |
489 | ||
b2a02fc4 | 490 | local_irq_restore(flags); |
3d442233 JA |
491 | } |
492 | ||
493 | /* | |
494 | * smp_call_function_single - Run a function on a specific CPU | |
495 | * @func: The function to run. This must be fast and non-blocking. | |
496 | * @info: An arbitrary pointer to pass to the function. | |
3d442233 JA |
497 | * @wait: If true, wait until function has completed on other CPUs. |
498 | * | |
72f279b2 | 499 | * Returns 0 on success, else a negative status code. |
3d442233 | 500 | */ |
3a5f65df | 501 | int smp_call_function_single(int cpu, smp_call_func_t func, void *info, |
8691e5a8 | 502 | int wait) |
3d442233 | 503 | { |
966a9671 YH |
504 | call_single_data_t *csd; |
505 | call_single_data_t csd_stack = { | |
545b8c8d | 506 | .node = { .u_flags = CSD_FLAG_LOCK | CSD_TYPE_SYNC, }, |
966a9671 | 507 | }; |
0b13fda1 | 508 | int this_cpu; |
8b28499a | 509 | int err; |
3d442233 | 510 | |
0b13fda1 IM |
511 | /* |
512 | * prevent preemption and reschedule on another processor, | |
513 | * as well as CPU removal | |
514 | */ | |
515 | this_cpu = get_cpu(); | |
516 | ||
269c861b SS |
517 | /* |
518 | * Can deadlock when called with interrupts disabled. | |
519 | * We allow cpu's that are not yet online though, as no one else can | |
520 | * send smp call function interrupt to this cpu and as such deadlocks | |
521 | * can't happen. | |
522 | */ | |
523 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
524 | && !oops_in_progress); | |
3d442233 | 525 | |
19dbdcb8 PZ |
526 | /* |
527 | * When @wait we can deadlock when we interrupt between llist_add() and | |
528 | * arch_send_call_function_ipi*(); when !@wait we can deadlock due to | |
529 | * csd_lock() on because the interrupt context uses the same csd | |
530 | * storage. | |
531 | */ | |
532 | WARN_ON_ONCE(!in_task()); | |
533 | ||
8053871d LT |
534 | csd = &csd_stack; |
535 | if (!wait) { | |
536 | csd = this_cpu_ptr(&csd_data); | |
537 | csd_lock(csd); | |
538 | } | |
539 | ||
4b44a21d PZ |
540 | csd->func = func; |
541 | csd->info = info; | |
35feb604 | 542 | #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG |
545b8c8d PZ |
543 | csd->node.src = smp_processor_id(); |
544 | csd->node.dst = cpu; | |
e48c15b7 | 545 | #endif |
4b44a21d PZ |
546 | |
547 | err = generic_exec_single(cpu, csd); | |
8053871d LT |
548 | |
549 | if (wait) | |
550 | csd_lock_wait(csd); | |
3d442233 JA |
551 | |
552 | put_cpu(); | |
0b13fda1 | 553 | |
f73be6de | 554 | return err; |
3d442233 JA |
555 | } |
556 | EXPORT_SYMBOL(smp_call_function_single); | |
557 | ||
d7877c03 | 558 | /** |
c46fff2a FW |
559 | * smp_call_function_single_async(): Run an asynchronous function on a |
560 | * specific CPU. | |
d7877c03 FW |
561 | * @cpu: The CPU to run on. |
562 | * @csd: Pre-allocated and setup data structure | |
d7877c03 | 563 | * |
c46fff2a FW |
564 | * Like smp_call_function_single(), but the call is asynchonous and |
565 | * can thus be done from contexts with disabled interrupts. | |
566 | * | |
567 | * The caller passes his own pre-allocated data structure | |
568 | * (ie: embedded in an object) and is responsible for synchronizing it | |
569 | * such that the IPIs performed on the @csd are strictly serialized. | |
570 | * | |
5a18ceca PX |
571 | * If the function is called with one csd which has not yet been |
572 | * processed by previous call to smp_call_function_single_async(), the | |
573 | * function will return immediately with -EBUSY showing that the csd | |
574 | * object is still in progress. | |
575 | * | |
c46fff2a FW |
576 | * NOTE: Be careful, there is unfortunately no current debugging facility to |
577 | * validate the correctness of this serialization. | |
d7877c03 | 578 | */ |
966a9671 | 579 | int smp_call_function_single_async(int cpu, call_single_data_t *csd) |
d7877c03 FW |
580 | { |
581 | int err = 0; | |
d7877c03 | 582 | |
fce8ad15 | 583 | preempt_disable(); |
8053871d | 584 | |
545b8c8d | 585 | if (csd->node.u_flags & CSD_FLAG_LOCK) { |
5a18ceca PX |
586 | err = -EBUSY; |
587 | goto out; | |
588 | } | |
8053871d | 589 | |
545b8c8d | 590 | csd->node.u_flags = CSD_FLAG_LOCK; |
8053871d LT |
591 | smp_wmb(); |
592 | ||
4b44a21d | 593 | err = generic_exec_single(cpu, csd); |
5a18ceca PX |
594 | |
595 | out: | |
fce8ad15 | 596 | preempt_enable(); |
d7877c03 FW |
597 | |
598 | return err; | |
599 | } | |
c46fff2a | 600 | EXPORT_SYMBOL_GPL(smp_call_function_single_async); |
d7877c03 | 601 | |
2ea6dec4 RR |
602 | /* |
603 | * smp_call_function_any - Run a function on any of the given cpus | |
604 | * @mask: The mask of cpus it can run on. | |
605 | * @func: The function to run. This must be fast and non-blocking. | |
606 | * @info: An arbitrary pointer to pass to the function. | |
607 | * @wait: If true, wait until function has completed. | |
608 | * | |
609 | * Returns 0 on success, else a negative status code (if no cpus were online). | |
2ea6dec4 RR |
610 | * |
611 | * Selection preference: | |
612 | * 1) current cpu if in @mask | |
613 | * 2) any cpu of current node if in @mask | |
614 | * 3) any other online cpu in @mask | |
615 | */ | |
616 | int smp_call_function_any(const struct cpumask *mask, | |
3a5f65df | 617 | smp_call_func_t func, void *info, int wait) |
2ea6dec4 RR |
618 | { |
619 | unsigned int cpu; | |
620 | const struct cpumask *nodemask; | |
621 | int ret; | |
622 | ||
623 | /* Try for same CPU (cheapest) */ | |
624 | cpu = get_cpu(); | |
625 | if (cpumask_test_cpu(cpu, mask)) | |
626 | goto call; | |
627 | ||
628 | /* Try for same node. */ | |
af2422c4 | 629 | nodemask = cpumask_of_node(cpu_to_node(cpu)); |
2ea6dec4 RR |
630 | for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; |
631 | cpu = cpumask_next_and(cpu, nodemask, mask)) { | |
632 | if (cpu_online(cpu)) | |
633 | goto call; | |
634 | } | |
635 | ||
636 | /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ | |
637 | cpu = cpumask_any_and(mask, cpu_online_mask); | |
638 | call: | |
639 | ret = smp_call_function_single(cpu, func, info, wait); | |
640 | put_cpu(); | |
641 | return ret; | |
642 | } | |
643 | EXPORT_SYMBOL_GPL(smp_call_function_any); | |
644 | ||
67719ef2 SAS |
645 | static void smp_call_function_many_cond(const struct cpumask *mask, |
646 | smp_call_func_t func, void *info, | |
647 | bool wait, smp_cond_func_t cond_func) | |
3d442233 | 648 | { |
e1d12f32 | 649 | struct call_function_data *cfd; |
9a46ad6d | 650 | int cpu, next_cpu, this_cpu = smp_processor_id(); |
3d442233 | 651 | |
269c861b SS |
652 | /* |
653 | * Can deadlock when called with interrupts disabled. | |
654 | * We allow cpu's that are not yet online though, as no one else can | |
655 | * send smp call function interrupt to this cpu and as such deadlocks | |
656 | * can't happen. | |
657 | */ | |
658 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
bd924e8c | 659 | && !oops_in_progress && !early_boot_irqs_disabled); |
3d442233 | 660 | |
19dbdcb8 PZ |
661 | /* |
662 | * When @wait we can deadlock when we interrupt between llist_add() and | |
663 | * arch_send_call_function_ipi*(); when !@wait we can deadlock due to | |
664 | * csd_lock() on because the interrupt context uses the same csd | |
665 | * storage. | |
666 | */ | |
667 | WARN_ON_ONCE(!in_task()); | |
668 | ||
723aae25 | 669 | /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */ |
54b11e6d | 670 | cpu = cpumask_first_and(mask, cpu_online_mask); |
0b13fda1 | 671 | if (cpu == this_cpu) |
54b11e6d | 672 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
0b13fda1 | 673 | |
54b11e6d RR |
674 | /* No online cpus? We're done. */ |
675 | if (cpu >= nr_cpu_ids) | |
676 | return; | |
677 | ||
678 | /* Do we have another CPU which isn't us? */ | |
679 | next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask); | |
0b13fda1 | 680 | if (next_cpu == this_cpu) |
54b11e6d RR |
681 | next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask); |
682 | ||
683 | /* Fastpath: do that cpu by itself. */ | |
684 | if (next_cpu >= nr_cpu_ids) { | |
25a3a154 | 685 | if (!cond_func || cond_func(cpu, info)) |
67719ef2 | 686 | smp_call_function_single(cpu, func, info, wait); |
54b11e6d | 687 | return; |
3d442233 JA |
688 | } |
689 | ||
bb964a92 | 690 | cfd = this_cpu_ptr(&cfd_data); |
45a57919 | 691 | |
e1d12f32 | 692 | cpumask_and(cfd->cpumask, mask, cpu_online_mask); |
6c8557bd | 693 | __cpumask_clear_cpu(this_cpu, cfd->cpumask); |
723aae25 MM |
694 | |
695 | /* Some callers race with other cpus changing the passed mask */ | |
e1d12f32 | 696 | if (unlikely(!cpumask_weight(cfd->cpumask))) |
723aae25 | 697 | return; |
3d442233 | 698 | |
3fc5b3b6 | 699 | cpumask_clear(cfd->cpumask_ipi); |
e1d12f32 | 700 | for_each_cpu(cpu, cfd->cpumask) { |
de7b09ef | 701 | call_single_data_t *csd = &per_cpu_ptr(cfd->pcpu, cpu)->csd; |
9a46ad6d | 702 | |
67719ef2 SAS |
703 | if (cond_func && !cond_func(cpu, info)) |
704 | continue; | |
705 | ||
9a46ad6d | 706 | csd_lock(csd); |
8053871d | 707 | if (wait) |
545b8c8d | 708 | csd->node.u_flags |= CSD_TYPE_SYNC; |
9a46ad6d SL |
709 | csd->func = func; |
710 | csd->info = info; | |
35feb604 | 711 | #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG |
545b8c8d PZ |
712 | csd->node.src = smp_processor_id(); |
713 | csd->node.dst = cpu; | |
e48c15b7 | 714 | #endif |
545b8c8d | 715 | if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) |
6c8557bd | 716 | __cpumask_set_cpu(cpu, cfd->cpumask_ipi); |
9a46ad6d | 717 | } |
561920a0 | 718 | |
3d442233 | 719 | /* Send a message to all CPUs in the map */ |
3fc5b3b6 | 720 | arch_send_call_function_ipi_mask(cfd->cpumask_ipi); |
3d442233 | 721 | |
9a46ad6d | 722 | if (wait) { |
e1d12f32 | 723 | for_each_cpu(cpu, cfd->cpumask) { |
966a9671 | 724 | call_single_data_t *csd; |
e1d12f32 | 725 | |
de7b09ef | 726 | csd = &per_cpu_ptr(cfd->pcpu, cpu)->csd; |
9a46ad6d SL |
727 | csd_lock_wait(csd); |
728 | } | |
729 | } | |
3d442233 | 730 | } |
67719ef2 SAS |
731 | |
732 | /** | |
733 | * smp_call_function_many(): Run a function on a set of other CPUs. | |
734 | * @mask: The set of cpus to run on (only runs on online subset). | |
735 | * @func: The function to run. This must be fast and non-blocking. | |
736 | * @info: An arbitrary pointer to pass to the function. | |
737 | * @wait: If true, wait (atomically) until function has completed | |
738 | * on other CPUs. | |
739 | * | |
740 | * If @wait is true, then returns once @func has returned. | |
741 | * | |
742 | * You must not call this function with disabled interrupts or from a | |
743 | * hardware interrupt handler or from a bottom half handler. Preemption | |
744 | * must be disabled when calling this function. | |
745 | */ | |
746 | void smp_call_function_many(const struct cpumask *mask, | |
747 | smp_call_func_t func, void *info, bool wait) | |
748 | { | |
749 | smp_call_function_many_cond(mask, func, info, wait, NULL); | |
750 | } | |
54b11e6d | 751 | EXPORT_SYMBOL(smp_call_function_many); |
3d442233 JA |
752 | |
753 | /** | |
754 | * smp_call_function(): Run a function on all other CPUs. | |
755 | * @func: The function to run. This must be fast and non-blocking. | |
756 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
757 | * @wait: If true, wait (atomically) until function has completed |
758 | * on other CPUs. | |
3d442233 | 759 | * |
54b11e6d | 760 | * Returns 0. |
3d442233 JA |
761 | * |
762 | * If @wait is true, then returns once @func has returned; otherwise | |
72f279b2 | 763 | * it returns just before the target cpu calls @func. |
3d442233 JA |
764 | * |
765 | * You must not call this function with disabled interrupts or from a | |
766 | * hardware interrupt handler or from a bottom half handler. | |
767 | */ | |
caa75932 | 768 | void smp_call_function(smp_call_func_t func, void *info, int wait) |
3d442233 | 769 | { |
3d442233 | 770 | preempt_disable(); |
54b11e6d | 771 | smp_call_function_many(cpu_online_mask, func, info, wait); |
3d442233 | 772 | preempt_enable(); |
3d442233 JA |
773 | } |
774 | EXPORT_SYMBOL(smp_call_function); | |
351f8f8e | 775 | |
34db18a0 AW |
776 | /* Setup configured maximum number of CPUs to activate */ |
777 | unsigned int setup_max_cpus = NR_CPUS; | |
778 | EXPORT_SYMBOL(setup_max_cpus); | |
779 | ||
780 | ||
781 | /* | |
782 | * Setup routine for controlling SMP activation | |
783 | * | |
784 | * Command-line option of "nosmp" or "maxcpus=0" will disable SMP | |
785 | * activation entirely (the MPS table probe still happens, though). | |
786 | * | |
787 | * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer | |
788 | * greater than 0, limits the maximum number of CPUs activated in | |
789 | * SMP mode to <NUM>. | |
790 | */ | |
791 | ||
792 | void __weak arch_disable_smp_support(void) { } | |
793 | ||
794 | static int __init nosmp(char *str) | |
795 | { | |
796 | setup_max_cpus = 0; | |
797 | arch_disable_smp_support(); | |
798 | ||
799 | return 0; | |
800 | } | |
801 | ||
802 | early_param("nosmp", nosmp); | |
803 | ||
804 | /* this is hard limit */ | |
805 | static int __init nrcpus(char *str) | |
806 | { | |
807 | int nr_cpus; | |
808 | ||
58934356 | 809 | if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids) |
34db18a0 AW |
810 | nr_cpu_ids = nr_cpus; |
811 | ||
812 | return 0; | |
813 | } | |
814 | ||
815 | early_param("nr_cpus", nrcpus); | |
816 | ||
817 | static int __init maxcpus(char *str) | |
818 | { | |
819 | get_option(&str, &setup_max_cpus); | |
820 | if (setup_max_cpus == 0) | |
821 | arch_disable_smp_support(); | |
822 | ||
823 | return 0; | |
824 | } | |
825 | ||
826 | early_param("maxcpus", maxcpus); | |
827 | ||
828 | /* Setup number of possible processor ids */ | |
9b130ad5 | 829 | unsigned int nr_cpu_ids __read_mostly = NR_CPUS; |
34db18a0 AW |
830 | EXPORT_SYMBOL(nr_cpu_ids); |
831 | ||
832 | /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ | |
833 | void __init setup_nr_cpu_ids(void) | |
834 | { | |
835 | nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; | |
836 | } | |
837 | ||
838 | /* Called by boot processor to activate the rest. */ | |
839 | void __init smp_init(void) | |
840 | { | |
92b23278 | 841 | int num_nodes, num_cpus; |
34db18a0 | 842 | |
3bb5d2ee | 843 | idle_threads_init(); |
4cb28ced | 844 | cpuhp_threads_init(); |
3bb5d2ee | 845 | |
51111dce ME |
846 | pr_info("Bringing up secondary CPUs ...\n"); |
847 | ||
b99a2659 | 848 | bringup_nonboot_cpus(setup_max_cpus); |
34db18a0 | 849 | |
92b23278 ME |
850 | num_nodes = num_online_nodes(); |
851 | num_cpus = num_online_cpus(); | |
852 | pr_info("Brought up %d node%s, %d CPU%s\n", | |
853 | num_nodes, (num_nodes > 1 ? "s" : ""), | |
854 | num_cpus, (num_cpus > 1 ? "s" : "")); | |
855 | ||
34db18a0 | 856 | /* Any cleanup work */ |
34db18a0 AW |
857 | smp_cpus_done(setup_max_cpus); |
858 | } | |
859 | ||
351f8f8e | 860 | /* |
bd924e8c TH |
861 | * Call a function on all processors. May be used during early boot while |
862 | * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead | |
863 | * of local_irq_disable/enable(). | |
351f8f8e | 864 | */ |
58eb7b77 | 865 | void on_each_cpu(smp_call_func_t func, void *info, int wait) |
351f8f8e | 866 | { |
bd924e8c | 867 | unsigned long flags; |
351f8f8e AW |
868 | |
869 | preempt_disable(); | |
caa75932 | 870 | smp_call_function(func, info, wait); |
bd924e8c | 871 | local_irq_save(flags); |
351f8f8e | 872 | func(info); |
bd924e8c | 873 | local_irq_restore(flags); |
351f8f8e | 874 | preempt_enable(); |
351f8f8e AW |
875 | } |
876 | EXPORT_SYMBOL(on_each_cpu); | |
3fc498f1 GBY |
877 | |
878 | /** | |
879 | * on_each_cpu_mask(): Run a function on processors specified by | |
880 | * cpumask, which may include the local processor. | |
881 | * @mask: The set of cpus to run on (only runs on online subset). | |
882 | * @func: The function to run. This must be fast and non-blocking. | |
883 | * @info: An arbitrary pointer to pass to the function. | |
884 | * @wait: If true, wait (atomically) until function has completed | |
885 | * on other CPUs. | |
886 | * | |
887 | * If @wait is true, then returns once @func has returned. | |
888 | * | |
202da400 DD |
889 | * You must not call this function with disabled interrupts or from a |
890 | * hardware interrupt handler or from a bottom half handler. The | |
891 | * exception is that it may be used during early boot while | |
892 | * early_boot_irqs_disabled is set. | |
3fc498f1 GBY |
893 | */ |
894 | void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, | |
895 | void *info, bool wait) | |
896 | { | |
897 | int cpu = get_cpu(); | |
898 | ||
899 | smp_call_function_many(mask, func, info, wait); | |
900 | if (cpumask_test_cpu(cpu, mask)) { | |
202da400 DD |
901 | unsigned long flags; |
902 | local_irq_save(flags); | |
3fc498f1 | 903 | func(info); |
202da400 | 904 | local_irq_restore(flags); |
3fc498f1 GBY |
905 | } |
906 | put_cpu(); | |
907 | } | |
908 | EXPORT_SYMBOL(on_each_cpu_mask); | |
b3a7e98e GBY |
909 | |
910 | /* | |
911 | * on_each_cpu_cond(): Call a function on each processor for which | |
912 | * the supplied function cond_func returns true, optionally waiting | |
913 | * for all the required CPUs to finish. This may include the local | |
914 | * processor. | |
915 | * @cond_func: A callback function that is passed a cpu id and | |
7b7b8a2c | 916 | * the info parameter. The function is called |
b3a7e98e GBY |
917 | * with preemption disabled. The function should |
918 | * return a blooean value indicating whether to IPI | |
919 | * the specified CPU. | |
920 | * @func: The function to run on all applicable CPUs. | |
921 | * This must be fast and non-blocking. | |
922 | * @info: An arbitrary pointer to pass to both functions. | |
923 | * @wait: If true, wait (atomically) until function has | |
924 | * completed on other CPUs. | |
b3a7e98e GBY |
925 | * |
926 | * Preemption is disabled to protect against CPUs going offline but not online. | |
927 | * CPUs going online during the call will not be seen or sent an IPI. | |
928 | * | |
929 | * You must not call this function with disabled interrupts or | |
930 | * from a hardware interrupt handler or from a bottom half handler. | |
931 | */ | |
5671d814 | 932 | void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, |
cb923159 | 933 | void *info, bool wait, const struct cpumask *mask) |
b3a7e98e | 934 | { |
67719ef2 SAS |
935 | int cpu = get_cpu(); |
936 | ||
937 | smp_call_function_many_cond(mask, func, info, wait, cond_func); | |
938 | if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) { | |
939 | unsigned long flags; | |
940 | ||
941 | local_irq_save(flags); | |
942 | func(info); | |
943 | local_irq_restore(flags); | |
b3a7e98e | 944 | } |
67719ef2 | 945 | put_cpu(); |
b3a7e98e | 946 | } |
7d49b28a RR |
947 | EXPORT_SYMBOL(on_each_cpu_cond_mask); |
948 | ||
5671d814 | 949 | void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func, |
cb923159 | 950 | void *info, bool wait) |
7d49b28a | 951 | { |
cb923159 | 952 | on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask); |
7d49b28a | 953 | } |
b3a7e98e | 954 | EXPORT_SYMBOL(on_each_cpu_cond); |
f37f435f TG |
955 | |
956 | static void do_nothing(void *unused) | |
957 | { | |
958 | } | |
959 | ||
960 | /** | |
961 | * kick_all_cpus_sync - Force all cpus out of idle | |
962 | * | |
963 | * Used to synchronize the update of pm_idle function pointer. It's | |
964 | * called after the pointer is updated and returns after the dummy | |
965 | * callback function has been executed on all cpus. The execution of | |
966 | * the function can only happen on the remote cpus after they have | |
967 | * left the idle function which had been called via pm_idle function | |
968 | * pointer. So it's guaranteed that nothing uses the previous pointer | |
969 | * anymore. | |
970 | */ | |
971 | void kick_all_cpus_sync(void) | |
972 | { | |
973 | /* Make sure the change is visible before we kick the cpus */ | |
974 | smp_mb(); | |
975 | smp_call_function(do_nothing, NULL, 1); | |
976 | } | |
977 | EXPORT_SYMBOL_GPL(kick_all_cpus_sync); | |
c6f4459f CL |
978 | |
979 | /** | |
980 | * wake_up_all_idle_cpus - break all cpus out of idle | |
981 | * wake_up_all_idle_cpus try to break all cpus which is in idle state even | |
982 | * including idle polling cpus, for non-idle cpus, we will do nothing | |
983 | * for them. | |
984 | */ | |
985 | void wake_up_all_idle_cpus(void) | |
986 | { | |
987 | int cpu; | |
988 | ||
989 | preempt_disable(); | |
990 | for_each_online_cpu(cpu) { | |
991 | if (cpu == smp_processor_id()) | |
992 | continue; | |
993 | ||
994 | wake_up_if_idle(cpu); | |
995 | } | |
996 | preempt_enable(); | |
997 | } | |
998 | EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); | |
df8ce9d7 JG |
999 | |
1000 | /** | |
1001 | * smp_call_on_cpu - Call a function on a specific cpu | |
1002 | * | |
1003 | * Used to call a function on a specific cpu and wait for it to return. | |
1004 | * Optionally make sure the call is done on a specified physical cpu via vcpu | |
1005 | * pinning in order to support virtualized environments. | |
1006 | */ | |
1007 | struct smp_call_on_cpu_struct { | |
1008 | struct work_struct work; | |
1009 | struct completion done; | |
1010 | int (*func)(void *); | |
1011 | void *data; | |
1012 | int ret; | |
1013 | int cpu; | |
1014 | }; | |
1015 | ||
1016 | static void smp_call_on_cpu_callback(struct work_struct *work) | |
1017 | { | |
1018 | struct smp_call_on_cpu_struct *sscs; | |
1019 | ||
1020 | sscs = container_of(work, struct smp_call_on_cpu_struct, work); | |
1021 | if (sscs->cpu >= 0) | |
1022 | hypervisor_pin_vcpu(sscs->cpu); | |
1023 | sscs->ret = sscs->func(sscs->data); | |
1024 | if (sscs->cpu >= 0) | |
1025 | hypervisor_pin_vcpu(-1); | |
1026 | ||
1027 | complete(&sscs->done); | |
1028 | } | |
1029 | ||
1030 | int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) | |
1031 | { | |
1032 | struct smp_call_on_cpu_struct sscs = { | |
df8ce9d7 JG |
1033 | .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), |
1034 | .func = func, | |
1035 | .data = par, | |
1036 | .cpu = phys ? cpu : -1, | |
1037 | }; | |
1038 | ||
8db54949 PZ |
1039 | INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback); |
1040 | ||
df8ce9d7 JG |
1041 | if (cpu >= nr_cpu_ids || !cpu_online(cpu)) |
1042 | return -ENXIO; | |
1043 | ||
1044 | queue_work_on(cpu, system_wq, &sscs.work); | |
1045 | wait_for_completion(&sscs.done); | |
1046 | ||
1047 | return sscs.ret; | |
1048 | } | |
1049 | EXPORT_SYMBOL_GPL(smp_call_on_cpu); |