Commit | Line | Data |
---|---|---|
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 JA |
33 | |
34 | struct call_function_data { | |
6366d062 | 35 | call_single_data_t __percpu *csd; |
0b13fda1 | 36 | cpumask_var_t cpumask; |
3fc5b3b6 | 37 | cpumask_var_t cpumask_ipi; |
3d442233 JA |
38 | }; |
39 | ||
a22793c7 | 40 | static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data); |
e03bcb68 | 41 | |
6897fc22 | 42 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); |
8969a5ed | 43 | |
16bf5a5e | 44 | static void __flush_smp_call_function_queue(bool warn_cpu_offline); |
8d056c48 | 45 | |
31487f83 | 46 | int smpcfd_prepare_cpu(unsigned int cpu) |
8969a5ed | 47 | { |
8969a5ed PZ |
48 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); |
49 | ||
31487f83 RW |
50 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, |
51 | cpu_to_node(cpu))) | |
52 | return -ENOMEM; | |
3fc5b3b6 AL |
53 | if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL, |
54 | cpu_to_node(cpu))) { | |
55 | free_cpumask_var(cfd->cpumask); | |
56 | return -ENOMEM; | |
57 | } | |
6366d062 PM |
58 | cfd->csd = alloc_percpu(call_single_data_t); |
59 | if (!cfd->csd) { | |
8969a5ed | 60 | free_cpumask_var(cfd->cpumask); |
3fc5b3b6 | 61 | free_cpumask_var(cfd->cpumask_ipi); |
31487f83 RW |
62 | return -ENOMEM; |
63 | } | |
64 | ||
65 | return 0; | |
8969a5ed PZ |
66 | } |
67 | ||
31487f83 RW |
68 | int smpcfd_dead_cpu(unsigned int cpu) |
69 | { | |
70 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); | |
71 | ||
72 | free_cpumask_var(cfd->cpumask); | |
3fc5b3b6 | 73 | free_cpumask_var(cfd->cpumask_ipi); |
6366d062 | 74 | free_percpu(cfd->csd); |
31487f83 RW |
75 | return 0; |
76 | } | |
77 | ||
78 | int smpcfd_dying_cpu(unsigned int cpu) | |
79 | { | |
80 | /* | |
81 | * The IPIs for the smp-call-function callbacks queued by other | |
82 | * CPUs might arrive late, either due to hardware latencies or | |
83 | * because this CPU disabled interrupts (inside stop-machine) | |
84 | * before the IPIs were sent. So flush out any pending callbacks | |
85 | * explicitly (without waiting for the IPIs to arrive), to | |
86 | * ensure that the outgoing CPU doesn't go offline with work | |
87 | * still pending. | |
88 | */ | |
16bf5a5e | 89 | __flush_smp_call_function_queue(false); |
afaa653c | 90 | irq_work_run(); |
31487f83 RW |
91 | return 0; |
92 | } | |
8969a5ed | 93 | |
d8ad7d11 | 94 | void __init call_function_init(void) |
3d442233 JA |
95 | { |
96 | int i; | |
97 | ||
6897fc22 CH |
98 | for_each_possible_cpu(i) |
99 | init_llist_head(&per_cpu(call_single_queue, i)); | |
8969a5ed | 100 | |
31487f83 | 101 | smpcfd_prepare_cpu(smp_processor_id()); |
3d442233 JA |
102 | } |
103 | ||
35feb604 PM |
104 | #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG |
105 | ||
c5219860 | 106 | static DEFINE_STATIC_KEY_MAYBE(CONFIG_CSD_LOCK_WAIT_DEBUG_DEFAULT, csdlock_debug_enabled); |
8d0968cc | 107 | |
1771257c PM |
108 | /* |
109 | * Parse the csdlock_debug= kernel boot parameter. | |
110 | * | |
111 | * If you need to restore the old "ext" value that once provided | |
112 | * additional debugging information, reapply the following commits: | |
113 | * | |
114 | * de7b09ef658d ("locking/csd_lock: Prepare more CSD lock debugging") | |
115 | * a5aabace5fb8 ("locking/csd_lock: Add more data to CSD lock debugging") | |
116 | */ | |
8d0968cc JG |
117 | static int __init csdlock_debug(char *str) |
118 | { | |
119 | unsigned int val = 0; | |
120 | ||
1771257c | 121 | get_option(&str, &val); |
8d0968cc JG |
122 | if (val) |
123 | static_branch_enable(&csdlock_debug_enabled); | |
124 | ||
9c9b26b0 | 125 | return 1; |
8d0968cc | 126 | } |
9c9b26b0 | 127 | __setup("csdlock_debug=", csdlock_debug); |
8d0968cc | 128 | |
35feb604 PM |
129 | static DEFINE_PER_CPU(call_single_data_t *, cur_csd); |
130 | static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func); | |
131 | static DEFINE_PER_CPU(void *, cur_csd_info); | |
132 | ||
3791a223 PM |
133 | static ulong csd_lock_timeout = 5000; /* CSD lock timeout in milliseconds. */ |
134 | module_param(csd_lock_timeout, ulong, 0444); | |
135 | ||
2b722160 | 136 | static atomic_t csd_bug_count = ATOMIC_INIT(0); |
35feb604 PM |
137 | |
138 | /* Record current CSD work for current CPU, NULL to erase. */ | |
1139aeb1 | 139 | static void __csd_lock_record(struct __call_single_data *csd) |
35feb604 PM |
140 | { |
141 | if (!csd) { | |
142 | smp_mb(); /* NULL cur_csd after unlock. */ | |
143 | __this_cpu_write(cur_csd, NULL); | |
144 | return; | |
145 | } | |
146 | __this_cpu_write(cur_csd_func, csd->func); | |
147 | __this_cpu_write(cur_csd_info, csd->info); | |
148 | smp_wmb(); /* func and info before csd. */ | |
149 | __this_cpu_write(cur_csd, csd); | |
150 | smp_mb(); /* Update cur_csd before function call. */ | |
151 | /* Or before unlock, as the case may be. */ | |
152 | } | |
153 | ||
1139aeb1 | 154 | static __always_inline void csd_lock_record(struct __call_single_data *csd) |
8d0968cc JG |
155 | { |
156 | if (static_branch_unlikely(&csdlock_debug_enabled)) | |
157 | __csd_lock_record(csd); | |
158 | } | |
159 | ||
1139aeb1 | 160 | static int csd_lock_wait_getcpu(struct __call_single_data *csd) |
35feb604 PM |
161 | { |
162 | unsigned int csd_type; | |
163 | ||
164 | csd_type = CSD_TYPE(csd); | |
165 | if (csd_type == CSD_TYPE_ASYNC || csd_type == CSD_TYPE_SYNC) | |
a787bdaf | 166 | return csd->node.dst; /* Other CSD_TYPE_ values might not have ->dst. */ |
35feb604 PM |
167 | return -1; |
168 | } | |
169 | ||
170 | /* | |
171 | * Complain if too much time spent waiting. Note that only | |
172 | * the CSD_TYPE_SYNC/ASYNC types provide the destination CPU, | |
173 | * so waiting on other types gets much less information. | |
174 | */ | |
1139aeb1 | 175 | static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *ts1, int *bug_id) |
35feb604 PM |
176 | { |
177 | int cpu = -1; | |
178 | int cpux; | |
179 | bool firsttime; | |
180 | u64 ts2, ts_delta; | |
181 | call_single_data_t *cpu_cur_csd; | |
545b8c8d | 182 | unsigned int flags = READ_ONCE(csd->node.u_flags); |
3791a223 | 183 | unsigned long long csd_lock_timeout_ns = csd_lock_timeout * NSEC_PER_MSEC; |
35feb604 PM |
184 | |
185 | if (!(flags & CSD_FLAG_LOCK)) { | |
186 | if (!unlikely(*bug_id)) | |
187 | return true; | |
188 | cpu = csd_lock_wait_getcpu(csd); | |
189 | pr_alert("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock.\n", | |
190 | *bug_id, raw_smp_processor_id(), cpu); | |
191 | return true; | |
192 | } | |
193 | ||
194 | ts2 = sched_clock(); | |
195 | ts_delta = ts2 - *ts1; | |
3791a223 | 196 | if (likely(ts_delta <= csd_lock_timeout_ns || csd_lock_timeout_ns == 0)) |
35feb604 PM |
197 | return false; |
198 | ||
199 | firsttime = !*bug_id; | |
200 | if (firsttime) | |
201 | *bug_id = atomic_inc_return(&csd_bug_count); | |
202 | cpu = csd_lock_wait_getcpu(csd); | |
203 | if (WARN_ONCE(cpu < 0 || cpu >= nr_cpu_ids, "%s: cpu = %d\n", __func__, cpu)) | |
204 | cpux = 0; | |
205 | else | |
206 | cpux = cpu; | |
207 | cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */ | |
208 | pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n", | |
209 | firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts2 - ts0, | |
210 | cpu, csd->func, csd->info); | |
211 | if (cpu_cur_csd && csd != cpu_cur_csd) { | |
212 | pr_alert("\tcsd: CSD lock (#%d) handling prior %pS(%ps) request.\n", | |
213 | *bug_id, READ_ONCE(per_cpu(cur_csd_func, cpux)), | |
214 | READ_ONCE(per_cpu(cur_csd_info, cpux))); | |
215 | } else { | |
216 | pr_alert("\tcsd: CSD lock (#%d) %s.\n", | |
217 | *bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request"); | |
218 | } | |
219 | if (cpu >= 0) { | |
e73dfe30 | 220 | dump_cpu_task(cpu); |
35feb604 PM |
221 | if (!cpu_cur_csd) { |
222 | pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu); | |
223 | arch_send_call_function_single_ipi(cpu); | |
224 | } | |
225 | } | |
226 | dump_stack(); | |
227 | *ts1 = ts2; | |
228 | ||
229 | return false; | |
230 | } | |
231 | ||
8969a5ed PZ |
232 | /* |
233 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources | |
234 | * | |
0b13fda1 IM |
235 | * For non-synchronous ipi calls the csd can still be in use by the |
236 | * previous function call. For multi-cpu calls its even more interesting | |
237 | * as we'll have to ensure no other cpu is observing our csd. | |
8969a5ed | 238 | */ |
1139aeb1 | 239 | static void __csd_lock_wait(struct __call_single_data *csd) |
35feb604 PM |
240 | { |
241 | int bug_id = 0; | |
242 | u64 ts0, ts1; | |
243 | ||
244 | ts1 = ts0 = sched_clock(); | |
245 | for (;;) { | |
246 | if (csd_lock_wait_toolong(csd, ts0, &ts1, &bug_id)) | |
247 | break; | |
248 | cpu_relax(); | |
249 | } | |
250 | smp_acquire__after_ctrl_dep(); | |
251 | } | |
252 | ||
1139aeb1 | 253 | static __always_inline void csd_lock_wait(struct __call_single_data *csd) |
8d0968cc JG |
254 | { |
255 | if (static_branch_unlikely(&csdlock_debug_enabled)) { | |
256 | __csd_lock_wait(csd); | |
257 | return; | |
258 | } | |
259 | ||
260 | smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK)); | |
261 | } | |
35feb604 | 262 | #else |
1139aeb1 | 263 | static void csd_lock_record(struct __call_single_data *csd) |
35feb604 PM |
264 | { |
265 | } | |
266 | ||
1139aeb1 | 267 | static __always_inline void csd_lock_wait(struct __call_single_data *csd) |
8969a5ed | 268 | { |
545b8c8d | 269 | smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK)); |
6e275637 | 270 | } |
35feb604 | 271 | #endif |
6e275637 | 272 | |
1139aeb1 | 273 | static __always_inline void csd_lock(struct __call_single_data *csd) |
6e275637 | 274 | { |
e1d12f32 | 275 | csd_lock_wait(csd); |
545b8c8d | 276 | csd->node.u_flags |= CSD_FLAG_LOCK; |
8969a5ed PZ |
277 | |
278 | /* | |
0b13fda1 IM |
279 | * prevent CPU from reordering the above assignment |
280 | * to ->flags with any subsequent assignments to other | |
966a9671 | 281 | * fields of the specified call_single_data_t structure: |
8969a5ed | 282 | */ |
8053871d | 283 | smp_wmb(); |
8969a5ed PZ |
284 | } |
285 | ||
1139aeb1 | 286 | static __always_inline void csd_unlock(struct __call_single_data *csd) |
8969a5ed | 287 | { |
545b8c8d | 288 | WARN_ON(!(csd->node.u_flags & CSD_FLAG_LOCK)); |
0b13fda1 | 289 | |
8969a5ed | 290 | /* |
0b13fda1 | 291 | * ensure we're all done before releasing data: |
8969a5ed | 292 | */ |
545b8c8d | 293 | smp_store_release(&csd->node.u_flags, 0); |
3d442233 JA |
294 | } |
295 | ||
966a9671 | 296 | static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data); |
8b28499a | 297 | |
4b44a21d PZ |
298 | void __smp_call_single_queue(int cpu, struct llist_node *node) |
299 | { | |
300 | /* | |
301 | * The list addition should be visible before sending the IPI | |
302 | * handler locks the list to pull the entry off it because of | |
303 | * normal cache coherency rules implied by spinlocks. | |
304 | * | |
305 | * If IPIs can go out of order to the cache coherency protocol | |
306 | * in an architecture, sufficient synchronisation should be added | |
307 | * to arch code to make it appear to obey cache coherency WRT | |
308 | * locking and barrier primitives. Generic code isn't really | |
309 | * equipped to do the right thing... | |
310 | */ | |
311 | if (llist_add(node, &per_cpu(call_single_queue, cpu))) | |
312 | send_call_function_single_ipi(cpu); | |
313 | } | |
314 | ||
3d442233 | 315 | /* |
966a9671 | 316 | * Insert a previously allocated call_single_data_t element |
0b13fda1 IM |
317 | * for execution on the given CPU. data must already have |
318 | * ->func, ->info, and ->flags set. | |
3d442233 | 319 | */ |
1139aeb1 | 320 | static int generic_exec_single(int cpu, struct __call_single_data *csd) |
3d442233 | 321 | { |
8b28499a | 322 | if (cpu == smp_processor_id()) { |
4b44a21d PZ |
323 | smp_call_func_t func = csd->func; |
324 | void *info = csd->info; | |
8053871d LT |
325 | unsigned long flags; |
326 | ||
327 | /* | |
328 | * We can unlock early even for the synchronous on-stack case, | |
329 | * since we're doing this from the same CPU.. | |
330 | */ | |
35feb604 | 331 | csd_lock_record(csd); |
8053871d | 332 | csd_unlock(csd); |
8b28499a FW |
333 | local_irq_save(flags); |
334 | func(info); | |
35feb604 | 335 | csd_lock_record(NULL); |
8b28499a FW |
336 | local_irq_restore(flags); |
337 | return 0; | |
338 | } | |
339 | ||
5224b961 LT |
340 | if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) { |
341 | csd_unlock(csd); | |
8b28499a | 342 | return -ENXIO; |
5224b961 | 343 | } |
8b28499a | 344 | |
545b8c8d | 345 | __smp_call_single_queue(cpu, &csd->node.llist); |
3d442233 | 346 | |
8b28499a | 347 | return 0; |
3d442233 JA |
348 | } |
349 | ||
8d056c48 SB |
350 | /** |
351 | * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks | |
352 | * | |
353 | * Invoked by arch to handle an IPI for call function single. | |
354 | * Must be called with interrupts disabled. | |
3d442233 JA |
355 | */ |
356 | void generic_smp_call_function_single_interrupt(void) | |
357 | { | |
16bf5a5e | 358 | __flush_smp_call_function_queue(true); |
8d056c48 SB |
359 | } |
360 | ||
361 | /** | |
16bf5a5e | 362 | * __flush_smp_call_function_queue - Flush pending smp-call-function callbacks |
8d056c48 SB |
363 | * |
364 | * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an | |
365 | * offline CPU. Skip this check if set to 'false'. | |
366 | * | |
367 | * Flush any pending smp-call-function callbacks queued on this CPU. This is | |
368 | * invoked by the generic IPI handler, as well as by a CPU about to go offline, | |
369 | * to ensure that all pending IPI callbacks are run before it goes completely | |
370 | * offline. | |
371 | * | |
372 | * Loop through the call_single_queue and run all the queued callbacks. | |
373 | * Must be called with interrupts disabled. | |
374 | */ | |
16bf5a5e | 375 | static void __flush_smp_call_function_queue(bool warn_cpu_offline) |
8d056c48 | 376 | { |
966a9671 | 377 | call_single_data_t *csd, *csd_next; |
52103be0 PZ |
378 | struct llist_node *entry, *prev; |
379 | struct llist_head *head; | |
a219ccf4 SB |
380 | static bool warned; |
381 | ||
83efcbd0 | 382 | lockdep_assert_irqs_disabled(); |
8d056c48 | 383 | |
bb964a92 | 384 | head = this_cpu_ptr(&call_single_queue); |
8d056c48 | 385 | entry = llist_del_all(head); |
a219ccf4 | 386 | entry = llist_reverse_order(entry); |
3d442233 | 387 | |
8d056c48 SB |
388 | /* There shouldn't be any pending callbacks on an offline CPU. */ |
389 | if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) && | |
9e949a38 | 390 | !warned && entry != NULL)) { |
a219ccf4 SB |
391 | warned = true; |
392 | WARN(1, "IPI on offline CPU %d\n", smp_processor_id()); | |
393 | ||
394 | /* | |
395 | * We don't have to use the _safe() variant here | |
396 | * because we are not invoking the IPI handlers yet. | |
397 | */ | |
545b8c8d | 398 | llist_for_each_entry(csd, entry, node.llist) { |
4b44a21d PZ |
399 | switch (CSD_TYPE(csd)) { |
400 | case CSD_TYPE_ASYNC: | |
401 | case CSD_TYPE_SYNC: | |
402 | case CSD_TYPE_IRQ_WORK: | |
403 | pr_warn("IPI callback %pS sent to offline CPU\n", | |
404 | csd->func); | |
405 | break; | |
406 | ||
a1488664 PZ |
407 | case CSD_TYPE_TTWU: |
408 | pr_warn("IPI task-wakeup sent to offline CPU\n"); | |
409 | break; | |
410 | ||
4b44a21d PZ |
411 | default: |
412 | pr_warn("IPI callback, unknown type %d, sent to offline CPU\n", | |
413 | CSD_TYPE(csd)); | |
414 | break; | |
415 | } | |
416 | } | |
a219ccf4 | 417 | } |
3d442233 | 418 | |
52103be0 PZ |
419 | /* |
420 | * First; run all SYNC callbacks, people are waiting for us. | |
421 | */ | |
422 | prev = NULL; | |
545b8c8d | 423 | llist_for_each_entry_safe(csd, csd_next, entry, node.llist) { |
8053871d | 424 | /* Do we wait until *after* callback? */ |
4b44a21d PZ |
425 | if (CSD_TYPE(csd) == CSD_TYPE_SYNC) { |
426 | smp_call_func_t func = csd->func; | |
427 | void *info = csd->info; | |
428 | ||
52103be0 | 429 | if (prev) { |
545b8c8d | 430 | prev->next = &csd_next->node.llist; |
52103be0 | 431 | } else { |
545b8c8d | 432 | entry = &csd_next->node.llist; |
52103be0 | 433 | } |
4b44a21d | 434 | |
35feb604 | 435 | csd_lock_record(csd); |
8053871d LT |
436 | func(info); |
437 | csd_unlock(csd); | |
35feb604 | 438 | csd_lock_record(NULL); |
8053871d | 439 | } else { |
545b8c8d | 440 | prev = &csd->node.llist; |
8053871d | 441 | } |
3d442233 | 442 | } |
47885016 | 443 | |
1771257c | 444 | if (!entry) |
a1488664 PZ |
445 | return; |
446 | ||
47885016 | 447 | /* |
52103be0 | 448 | * Second; run all !SYNC callbacks. |
47885016 | 449 | */ |
a1488664 | 450 | prev = NULL; |
545b8c8d | 451 | llist_for_each_entry_safe(csd, csd_next, entry, node.llist) { |
4b44a21d | 452 | int type = CSD_TYPE(csd); |
52103be0 | 453 | |
a1488664 PZ |
454 | if (type != CSD_TYPE_TTWU) { |
455 | if (prev) { | |
545b8c8d | 456 | prev->next = &csd_next->node.llist; |
a1488664 | 457 | } else { |
545b8c8d | 458 | entry = &csd_next->node.llist; |
a1488664 | 459 | } |
4b44a21d | 460 | |
a1488664 PZ |
461 | if (type == CSD_TYPE_ASYNC) { |
462 | smp_call_func_t func = csd->func; | |
463 | void *info = csd->info; | |
464 | ||
35feb604 | 465 | csd_lock_record(csd); |
a1488664 PZ |
466 | csd_unlock(csd); |
467 | func(info); | |
35feb604 | 468 | csd_lock_record(NULL); |
a1488664 PZ |
469 | } else if (type == CSD_TYPE_IRQ_WORK) { |
470 | irq_work_single(csd); | |
471 | } | |
472 | ||
473 | } else { | |
545b8c8d | 474 | prev = &csd->node.llist; |
4b44a21d | 475 | } |
52103be0 | 476 | } |
a1488664 PZ |
477 | |
478 | /* | |
479 | * Third; only CSD_TYPE_TTWU is left, issue those. | |
480 | */ | |
481 | if (entry) | |
482 | sched_ttwu_pending(entry); | |
3d442233 JA |
483 | } |
484 | ||
16bf5a5e TG |
485 | |
486 | /** | |
487 | * flush_smp_call_function_queue - Flush pending smp-call-function callbacks | |
488 | * from task context (idle, migration thread) | |
489 | * | |
490 | * When TIF_POLLING_NRFLAG is supported and a CPU is in idle and has it | |
491 | * set, then remote CPUs can avoid sending IPIs and wake the idle CPU by | |
492 | * setting TIF_NEED_RESCHED. The idle task on the woken up CPU has to | |
493 | * handle queued SMP function calls before scheduling. | |
494 | * | |
495 | * The migration thread has to ensure that an eventually pending wakeup has | |
496 | * been handled before it migrates a task. | |
497 | */ | |
498 | void flush_smp_call_function_queue(void) | |
b2a02fc4 | 499 | { |
1a90bfd2 | 500 | unsigned int was_pending; |
b2a02fc4 PZ |
501 | unsigned long flags; |
502 | ||
503 | if (llist_empty(this_cpu_ptr(&call_single_queue))) | |
504 | return; | |
505 | ||
506 | local_irq_save(flags); | |
1a90bfd2 SAS |
507 | /* Get the already pending soft interrupts for RT enabled kernels */ |
508 | was_pending = local_softirq_pending(); | |
16bf5a5e | 509 | __flush_smp_call_function_queue(true); |
f9d34595 | 510 | if (local_softirq_pending()) |
1a90bfd2 | 511 | do_softirq_post_smp_call_flush(was_pending); |
f9d34595 | 512 | |
b2a02fc4 | 513 | local_irq_restore(flags); |
3d442233 JA |
514 | } |
515 | ||
516 | /* | |
517 | * smp_call_function_single - Run a function on a specific CPU | |
518 | * @func: The function to run. This must be fast and non-blocking. | |
519 | * @info: An arbitrary pointer to pass to the function. | |
3d442233 JA |
520 | * @wait: If true, wait until function has completed on other CPUs. |
521 | * | |
72f279b2 | 522 | * Returns 0 on success, else a negative status code. |
3d442233 | 523 | */ |
3a5f65df | 524 | int smp_call_function_single(int cpu, smp_call_func_t func, void *info, |
8691e5a8 | 525 | int wait) |
3d442233 | 526 | { |
966a9671 YH |
527 | call_single_data_t *csd; |
528 | call_single_data_t csd_stack = { | |
545b8c8d | 529 | .node = { .u_flags = CSD_FLAG_LOCK | CSD_TYPE_SYNC, }, |
966a9671 | 530 | }; |
0b13fda1 | 531 | int this_cpu; |
8b28499a | 532 | int err; |
3d442233 | 533 | |
0b13fda1 IM |
534 | /* |
535 | * prevent preemption and reschedule on another processor, | |
536 | * as well as CPU removal | |
537 | */ | |
538 | this_cpu = get_cpu(); | |
539 | ||
269c861b SS |
540 | /* |
541 | * Can deadlock when called with interrupts disabled. | |
542 | * We allow cpu's that are not yet online though, as no one else can | |
543 | * send smp call function interrupt to this cpu and as such deadlocks | |
544 | * can't happen. | |
545 | */ | |
546 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
547 | && !oops_in_progress); | |
3d442233 | 548 | |
19dbdcb8 PZ |
549 | /* |
550 | * When @wait we can deadlock when we interrupt between llist_add() and | |
551 | * arch_send_call_function_ipi*(); when !@wait we can deadlock due to | |
552 | * csd_lock() on because the interrupt context uses the same csd | |
553 | * storage. | |
554 | */ | |
555 | WARN_ON_ONCE(!in_task()); | |
556 | ||
8053871d LT |
557 | csd = &csd_stack; |
558 | if (!wait) { | |
559 | csd = this_cpu_ptr(&csd_data); | |
560 | csd_lock(csd); | |
561 | } | |
562 | ||
4b44a21d PZ |
563 | csd->func = func; |
564 | csd->info = info; | |
35feb604 | 565 | #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG |
545b8c8d PZ |
566 | csd->node.src = smp_processor_id(); |
567 | csd->node.dst = cpu; | |
e48c15b7 | 568 | #endif |
4b44a21d PZ |
569 | |
570 | err = generic_exec_single(cpu, csd); | |
8053871d LT |
571 | |
572 | if (wait) | |
573 | csd_lock_wait(csd); | |
3d442233 JA |
574 | |
575 | put_cpu(); | |
0b13fda1 | 576 | |
f73be6de | 577 | return err; |
3d442233 JA |
578 | } |
579 | EXPORT_SYMBOL(smp_call_function_single); | |
580 | ||
d7877c03 | 581 | /** |
49b3bd21 | 582 | * smp_call_function_single_async() - Run an asynchronous function on a |
c46fff2a | 583 | * specific CPU. |
d7877c03 FW |
584 | * @cpu: The CPU to run on. |
585 | * @csd: Pre-allocated and setup data structure | |
d7877c03 | 586 | * |
c46fff2a FW |
587 | * Like smp_call_function_single(), but the call is asynchonous and |
588 | * can thus be done from contexts with disabled interrupts. | |
589 | * | |
590 | * The caller passes his own pre-allocated data structure | |
591 | * (ie: embedded in an object) and is responsible for synchronizing it | |
592 | * such that the IPIs performed on the @csd are strictly serialized. | |
593 | * | |
5a18ceca PX |
594 | * If the function is called with one csd which has not yet been |
595 | * processed by previous call to smp_call_function_single_async(), the | |
596 | * function will return immediately with -EBUSY showing that the csd | |
597 | * object is still in progress. | |
598 | * | |
c46fff2a FW |
599 | * NOTE: Be careful, there is unfortunately no current debugging facility to |
600 | * validate the correctness of this serialization. | |
49b3bd21 RD |
601 | * |
602 | * Return: %0 on success or negative errno value on error | |
d7877c03 | 603 | */ |
1139aeb1 | 604 | int smp_call_function_single_async(int cpu, struct __call_single_data *csd) |
d7877c03 FW |
605 | { |
606 | int err = 0; | |
d7877c03 | 607 | |
fce8ad15 | 608 | preempt_disable(); |
8053871d | 609 | |
545b8c8d | 610 | if (csd->node.u_flags & CSD_FLAG_LOCK) { |
5a18ceca PX |
611 | err = -EBUSY; |
612 | goto out; | |
613 | } | |
8053871d | 614 | |
545b8c8d | 615 | csd->node.u_flags = CSD_FLAG_LOCK; |
8053871d LT |
616 | smp_wmb(); |
617 | ||
4b44a21d | 618 | err = generic_exec_single(cpu, csd); |
5a18ceca PX |
619 | |
620 | out: | |
fce8ad15 | 621 | preempt_enable(); |
d7877c03 FW |
622 | |
623 | return err; | |
624 | } | |
c46fff2a | 625 | EXPORT_SYMBOL_GPL(smp_call_function_single_async); |
d7877c03 | 626 | |
2ea6dec4 RR |
627 | /* |
628 | * smp_call_function_any - Run a function on any of the given cpus | |
629 | * @mask: The mask of cpus it can run on. | |
630 | * @func: The function to run. This must be fast and non-blocking. | |
631 | * @info: An arbitrary pointer to pass to the function. | |
632 | * @wait: If true, wait until function has completed. | |
633 | * | |
634 | * Returns 0 on success, else a negative status code (if no cpus were online). | |
2ea6dec4 RR |
635 | * |
636 | * Selection preference: | |
637 | * 1) current cpu if in @mask | |
638 | * 2) any cpu of current node if in @mask | |
639 | * 3) any other online cpu in @mask | |
640 | */ | |
641 | int smp_call_function_any(const struct cpumask *mask, | |
3a5f65df | 642 | smp_call_func_t func, void *info, int wait) |
2ea6dec4 RR |
643 | { |
644 | unsigned int cpu; | |
645 | const struct cpumask *nodemask; | |
646 | int ret; | |
647 | ||
648 | /* Try for same CPU (cheapest) */ | |
649 | cpu = get_cpu(); | |
650 | if (cpumask_test_cpu(cpu, mask)) | |
651 | goto call; | |
652 | ||
653 | /* Try for same node. */ | |
af2422c4 | 654 | nodemask = cpumask_of_node(cpu_to_node(cpu)); |
2ea6dec4 RR |
655 | for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; |
656 | cpu = cpumask_next_and(cpu, nodemask, mask)) { | |
657 | if (cpu_online(cpu)) | |
658 | goto call; | |
659 | } | |
660 | ||
661 | /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ | |
662 | cpu = cpumask_any_and(mask, cpu_online_mask); | |
663 | call: | |
664 | ret = smp_call_function_single(cpu, func, info, wait); | |
665 | put_cpu(); | |
666 | return ret; | |
667 | } | |
668 | EXPORT_SYMBOL_GPL(smp_call_function_any); | |
669 | ||
a32a4d8a NA |
670 | /* |
671 | * Flags to be used as scf_flags argument of smp_call_function_many_cond(). | |
672 | * | |
673 | * %SCF_WAIT: Wait until function execution is completed | |
674 | * %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask | |
675 | */ | |
676 | #define SCF_WAIT (1U << 0) | |
677 | #define SCF_RUN_LOCAL (1U << 1) | |
678 | ||
67719ef2 SAS |
679 | static void smp_call_function_many_cond(const struct cpumask *mask, |
680 | smp_call_func_t func, void *info, | |
a32a4d8a NA |
681 | unsigned int scf_flags, |
682 | smp_cond_func_t cond_func) | |
3d442233 | 683 | { |
a32a4d8a | 684 | int cpu, last_cpu, this_cpu = smp_processor_id(); |
e1d12f32 | 685 | struct call_function_data *cfd; |
a32a4d8a NA |
686 | bool wait = scf_flags & SCF_WAIT; |
687 | bool run_remote = false; | |
688 | bool run_local = false; | |
689 | int nr_cpus = 0; | |
690 | ||
691 | lockdep_assert_preemption_disabled(); | |
3d442233 | 692 | |
269c861b SS |
693 | /* |
694 | * Can deadlock when called with interrupts disabled. | |
695 | * We allow cpu's that are not yet online though, as no one else can | |
696 | * send smp call function interrupt to this cpu and as such deadlocks | |
697 | * can't happen. | |
698 | */ | |
a32a4d8a NA |
699 | if (cpu_online(this_cpu) && !oops_in_progress && |
700 | !early_boot_irqs_disabled) | |
701 | lockdep_assert_irqs_enabled(); | |
3d442233 | 702 | |
19dbdcb8 PZ |
703 | /* |
704 | * When @wait we can deadlock when we interrupt between llist_add() and | |
705 | * arch_send_call_function_ipi*(); when !@wait we can deadlock due to | |
706 | * csd_lock() on because the interrupt context uses the same csd | |
707 | * storage. | |
708 | */ | |
709 | WARN_ON_ONCE(!in_task()); | |
710 | ||
a32a4d8a NA |
711 | /* Check if we need local execution. */ |
712 | if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask)) | |
713 | run_local = true; | |
714 | ||
715 | /* Check if we need remote execution, i.e., any CPU excluding this one. */ | |
54b11e6d | 716 | cpu = cpumask_first_and(mask, cpu_online_mask); |
0b13fda1 | 717 | if (cpu == this_cpu) |
54b11e6d | 718 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
a32a4d8a NA |
719 | if (cpu < nr_cpu_ids) |
720 | run_remote = true; | |
0b13fda1 | 721 | |
a32a4d8a NA |
722 | if (run_remote) { |
723 | cfd = this_cpu_ptr(&cfd_data); | |
724 | cpumask_and(cfd->cpumask, mask, cpu_online_mask); | |
725 | __cpumask_clear_cpu(this_cpu, cfd->cpumask); | |
45a57919 | 726 | |
a32a4d8a NA |
727 | cpumask_clear(cfd->cpumask_ipi); |
728 | for_each_cpu(cpu, cfd->cpumask) { | |
6366d062 | 729 | call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu); |
9a46ad6d | 730 | |
a32a4d8a NA |
731 | if (cond_func && !cond_func(cpu, info)) |
732 | continue; | |
67719ef2 | 733 | |
a32a4d8a NA |
734 | csd_lock(csd); |
735 | if (wait) | |
736 | csd->node.u_flags |= CSD_TYPE_SYNC; | |
737 | csd->func = func; | |
738 | csd->info = info; | |
35feb604 | 739 | #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG |
a32a4d8a NA |
740 | csd->node.src = smp_processor_id(); |
741 | csd->node.dst = cpu; | |
e48c15b7 | 742 | #endif |
a32a4d8a NA |
743 | if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) { |
744 | __cpumask_set_cpu(cpu, cfd->cpumask_ipi); | |
745 | nr_cpus++; | |
746 | last_cpu = cpu; | |
747 | } | |
748 | } | |
749 | ||
750 | /* | |
751 | * Choose the most efficient way to send an IPI. Note that the | |
752 | * number of CPUs might be zero due to concurrent changes to the | |
753 | * provided mask. | |
754 | */ | |
755 | if (nr_cpus == 1) | |
d43f17a1 | 756 | send_call_function_single_ipi(last_cpu); |
a32a4d8a NA |
757 | else if (likely(nr_cpus > 1)) |
758 | arch_send_call_function_ipi_mask(cfd->cpumask_ipi); | |
9a46ad6d | 759 | } |
561920a0 | 760 | |
a32a4d8a NA |
761 | if (run_local && (!cond_func || cond_func(this_cpu, info))) { |
762 | unsigned long flags; | |
763 | ||
764 | local_irq_save(flags); | |
765 | func(info); | |
766 | local_irq_restore(flags); | |
767 | } | |
3d442233 | 768 | |
a32a4d8a | 769 | if (run_remote && wait) { |
e1d12f32 | 770 | for_each_cpu(cpu, cfd->cpumask) { |
966a9671 | 771 | call_single_data_t *csd; |
e1d12f32 | 772 | |
6366d062 | 773 | csd = per_cpu_ptr(cfd->csd, cpu); |
9a46ad6d SL |
774 | csd_lock_wait(csd); |
775 | } | |
776 | } | |
3d442233 | 777 | } |
67719ef2 SAS |
778 | |
779 | /** | |
a32a4d8a | 780 | * smp_call_function_many(): Run a function on a set of CPUs. |
67719ef2 SAS |
781 | * @mask: The set of cpus to run on (only runs on online subset). |
782 | * @func: The function to run. This must be fast and non-blocking. | |
783 | * @info: An arbitrary pointer to pass to the function. | |
49b3bd21 | 784 | * @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait |
a32a4d8a NA |
785 | * (atomically) until function has completed on other CPUs. If |
786 | * %SCF_RUN_LOCAL is set, the function will also be run locally | |
787 | * if the local CPU is set in the @cpumask. | |
67719ef2 SAS |
788 | * |
789 | * If @wait is true, then returns once @func has returned. | |
790 | * | |
791 | * You must not call this function with disabled interrupts or from a | |
792 | * hardware interrupt handler or from a bottom half handler. Preemption | |
793 | * must be disabled when calling this function. | |
794 | */ | |
795 | void smp_call_function_many(const struct cpumask *mask, | |
796 | smp_call_func_t func, void *info, bool wait) | |
797 | { | |
a32a4d8a | 798 | smp_call_function_many_cond(mask, func, info, wait * SCF_WAIT, NULL); |
67719ef2 | 799 | } |
54b11e6d | 800 | EXPORT_SYMBOL(smp_call_function_many); |
3d442233 JA |
801 | |
802 | /** | |
803 | * smp_call_function(): Run a function on all other CPUs. | |
804 | * @func: The function to run. This must be fast and non-blocking. | |
805 | * @info: An arbitrary pointer to pass to the function. | |
0b13fda1 IM |
806 | * @wait: If true, wait (atomically) until function has completed |
807 | * on other CPUs. | |
3d442233 | 808 | * |
54b11e6d | 809 | * Returns 0. |
3d442233 JA |
810 | * |
811 | * If @wait is true, then returns once @func has returned; otherwise | |
72f279b2 | 812 | * it returns just before the target cpu calls @func. |
3d442233 JA |
813 | * |
814 | * You must not call this function with disabled interrupts or from a | |
815 | * hardware interrupt handler or from a bottom half handler. | |
816 | */ | |
caa75932 | 817 | void smp_call_function(smp_call_func_t func, void *info, int wait) |
3d442233 | 818 | { |
3d442233 | 819 | preempt_disable(); |
54b11e6d | 820 | smp_call_function_many(cpu_online_mask, func, info, wait); |
3d442233 | 821 | preempt_enable(); |
3d442233 JA |
822 | } |
823 | EXPORT_SYMBOL(smp_call_function); | |
351f8f8e | 824 | |
34db18a0 AW |
825 | /* Setup configured maximum number of CPUs to activate */ |
826 | unsigned int setup_max_cpus = NR_CPUS; | |
827 | EXPORT_SYMBOL(setup_max_cpus); | |
828 | ||
829 | ||
830 | /* | |
831 | * Setup routine for controlling SMP activation | |
832 | * | |
833 | * Command-line option of "nosmp" or "maxcpus=0" will disable SMP | |
834 | * activation entirely (the MPS table probe still happens, though). | |
835 | * | |
836 | * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer | |
837 | * greater than 0, limits the maximum number of CPUs activated in | |
838 | * SMP mode to <NUM>. | |
839 | */ | |
840 | ||
841 | void __weak arch_disable_smp_support(void) { } | |
842 | ||
843 | static int __init nosmp(char *str) | |
844 | { | |
845 | setup_max_cpus = 0; | |
846 | arch_disable_smp_support(); | |
847 | ||
848 | return 0; | |
849 | } | |
850 | ||
851 | early_param("nosmp", nosmp); | |
852 | ||
853 | /* this is hard limit */ | |
854 | static int __init nrcpus(char *str) | |
855 | { | |
856 | int nr_cpus; | |
857 | ||
58934356 | 858 | if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids) |
38bef8e5 | 859 | set_nr_cpu_ids(nr_cpus); |
34db18a0 AW |
860 | |
861 | return 0; | |
862 | } | |
863 | ||
864 | early_param("nr_cpus", nrcpus); | |
865 | ||
866 | static int __init maxcpus(char *str) | |
867 | { | |
868 | get_option(&str, &setup_max_cpus); | |
869 | if (setup_max_cpus == 0) | |
870 | arch_disable_smp_support(); | |
871 | ||
872 | return 0; | |
873 | } | |
874 | ||
875 | early_param("maxcpus", maxcpus); | |
876 | ||
6f9c07be | 877 | #if (NR_CPUS > 1) && !defined(CONFIG_FORCE_NR_CPUS) |
34db18a0 | 878 | /* Setup number of possible processor ids */ |
9b130ad5 | 879 | unsigned int nr_cpu_ids __read_mostly = NR_CPUS; |
34db18a0 | 880 | EXPORT_SYMBOL(nr_cpu_ids); |
53fc190c | 881 | #endif |
34db18a0 AW |
882 | |
883 | /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ | |
884 | void __init setup_nr_cpu_ids(void) | |
885 | { | |
38bef8e5 | 886 | set_nr_cpu_ids(find_last_bit(cpumask_bits(cpu_possible_mask), NR_CPUS) + 1); |
34db18a0 AW |
887 | } |
888 | ||
889 | /* Called by boot processor to activate the rest. */ | |
890 | void __init smp_init(void) | |
891 | { | |
92b23278 | 892 | int num_nodes, num_cpus; |
34db18a0 | 893 | |
3bb5d2ee | 894 | idle_threads_init(); |
4cb28ced | 895 | cpuhp_threads_init(); |
3bb5d2ee | 896 | |
51111dce ME |
897 | pr_info("Bringing up secondary CPUs ...\n"); |
898 | ||
b99a2659 | 899 | bringup_nonboot_cpus(setup_max_cpus); |
34db18a0 | 900 | |
92b23278 ME |
901 | num_nodes = num_online_nodes(); |
902 | num_cpus = num_online_cpus(); | |
903 | pr_info("Brought up %d node%s, %d CPU%s\n", | |
904 | num_nodes, (num_nodes > 1 ? "s" : ""), | |
905 | num_cpus, (num_cpus > 1 ? "s" : "")); | |
906 | ||
34db18a0 | 907 | /* Any cleanup work */ |
34db18a0 AW |
908 | smp_cpus_done(setup_max_cpus); |
909 | } | |
910 | ||
b3a7e98e GBY |
911 | /* |
912 | * on_each_cpu_cond(): Call a function on each processor for which | |
913 | * the supplied function cond_func returns true, optionally waiting | |
914 | * for all the required CPUs to finish. This may include the local | |
915 | * processor. | |
916 | * @cond_func: A callback function that is passed a cpu id and | |
7b7b8a2c | 917 | * the info parameter. The function is called |
b3a7e98e GBY |
918 | * with preemption disabled. The function should |
919 | * return a blooean value indicating whether to IPI | |
920 | * the specified CPU. | |
921 | * @func: The function to run on all applicable CPUs. | |
922 | * This must be fast and non-blocking. | |
923 | * @info: An arbitrary pointer to pass to both functions. | |
924 | * @wait: If true, wait (atomically) until function has | |
925 | * completed on other CPUs. | |
b3a7e98e GBY |
926 | * |
927 | * Preemption is disabled to protect against CPUs going offline but not online. | |
928 | * CPUs going online during the call will not be seen or sent an IPI. | |
929 | * | |
930 | * You must not call this function with disabled interrupts or | |
931 | * from a hardware interrupt handler or from a bottom half handler. | |
932 | */ | |
5671d814 | 933 | void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, |
cb923159 | 934 | void *info, bool wait, const struct cpumask *mask) |
b3a7e98e | 935 | { |
a32a4d8a | 936 | unsigned int scf_flags = SCF_RUN_LOCAL; |
67719ef2 | 937 | |
a32a4d8a NA |
938 | if (wait) |
939 | scf_flags |= SCF_WAIT; | |
67719ef2 | 940 | |
a32a4d8a NA |
941 | preempt_disable(); |
942 | smp_call_function_many_cond(mask, func, info, scf_flags, cond_func); | |
943 | preempt_enable(); | |
b3a7e98e | 944 | } |
7d49b28a RR |
945 | EXPORT_SYMBOL(on_each_cpu_cond_mask); |
946 | ||
f37f435f TG |
947 | static void do_nothing(void *unused) |
948 | { | |
949 | } | |
950 | ||
951 | /** | |
952 | * kick_all_cpus_sync - Force all cpus out of idle | |
953 | * | |
954 | * Used to synchronize the update of pm_idle function pointer. It's | |
955 | * called after the pointer is updated and returns after the dummy | |
956 | * callback function has been executed on all cpus. The execution of | |
957 | * the function can only happen on the remote cpus after they have | |
958 | * left the idle function which had been called via pm_idle function | |
959 | * pointer. So it's guaranteed that nothing uses the previous pointer | |
960 | * anymore. | |
961 | */ | |
962 | void kick_all_cpus_sync(void) | |
963 | { | |
964 | /* Make sure the change is visible before we kick the cpus */ | |
965 | smp_mb(); | |
966 | smp_call_function(do_nothing, NULL, 1); | |
967 | } | |
968 | EXPORT_SYMBOL_GPL(kick_all_cpus_sync); | |
c6f4459f CL |
969 | |
970 | /** | |
971 | * wake_up_all_idle_cpus - break all cpus out of idle | |
972 | * wake_up_all_idle_cpus try to break all cpus which is in idle state even | |
973 | * including idle polling cpus, for non-idle cpus, we will do nothing | |
974 | * for them. | |
975 | */ | |
976 | void wake_up_all_idle_cpus(void) | |
977 | { | |
978 | int cpu; | |
979 | ||
96611c26 PZ |
980 | for_each_possible_cpu(cpu) { |
981 | preempt_disable(); | |
982 | if (cpu != smp_processor_id() && cpu_online(cpu)) | |
983 | wake_up_if_idle(cpu); | |
984 | preempt_enable(); | |
c6f4459f | 985 | } |
c6f4459f CL |
986 | } |
987 | EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); | |
df8ce9d7 JG |
988 | |
989 | /** | |
49b3bd21 RD |
990 | * struct smp_call_on_cpu_struct - Call a function on a specific CPU |
991 | * @work: &work_struct | |
992 | * @done: &completion to signal | |
993 | * @func: function to call | |
994 | * @data: function's data argument | |
995 | * @ret: return value from @func | |
996 | * @cpu: target CPU (%-1 for any CPU) | |
df8ce9d7 JG |
997 | * |
998 | * Used to call a function on a specific cpu and wait for it to return. | |
999 | * Optionally make sure the call is done on a specified physical cpu via vcpu | |
1000 | * pinning in order to support virtualized environments. | |
1001 | */ | |
1002 | struct smp_call_on_cpu_struct { | |
1003 | struct work_struct work; | |
1004 | struct completion done; | |
1005 | int (*func)(void *); | |
1006 | void *data; | |
1007 | int ret; | |
1008 | int cpu; | |
1009 | }; | |
1010 | ||
1011 | static void smp_call_on_cpu_callback(struct work_struct *work) | |
1012 | { | |
1013 | struct smp_call_on_cpu_struct *sscs; | |
1014 | ||
1015 | sscs = container_of(work, struct smp_call_on_cpu_struct, work); | |
1016 | if (sscs->cpu >= 0) | |
1017 | hypervisor_pin_vcpu(sscs->cpu); | |
1018 | sscs->ret = sscs->func(sscs->data); | |
1019 | if (sscs->cpu >= 0) | |
1020 | hypervisor_pin_vcpu(-1); | |
1021 | ||
1022 | complete(&sscs->done); | |
1023 | } | |
1024 | ||
1025 | int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) | |
1026 | { | |
1027 | struct smp_call_on_cpu_struct sscs = { | |
df8ce9d7 JG |
1028 | .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), |
1029 | .func = func, | |
1030 | .data = par, | |
1031 | .cpu = phys ? cpu : -1, | |
1032 | }; | |
1033 | ||
8db54949 PZ |
1034 | INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback); |
1035 | ||
df8ce9d7 JG |
1036 | if (cpu >= nr_cpu_ids || !cpu_online(cpu)) |
1037 | return -ENXIO; | |
1038 | ||
1039 | queue_work_on(cpu, system_wq, &sscs.work); | |
1040 | wait_for_completion(&sscs.done); | |
1041 | ||
1042 | return sscs.ret; | |
1043 | } | |
1044 | EXPORT_SYMBOL_GPL(smp_call_on_cpu); |