1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __CPUHOTPLUG_H
3#define __CPUHOTPLUG_H
4
5#include <linux/types.h>
6
7/*
8 * CPU-up CPU-down
9 *
10 * BP AP BP AP
11 *
12 * OFFLINE OFFLINE
13 * | ^
14 * v |
15 * BRINGUP_CPU->AP_OFFLINE BRINGUP_CPU <- AP_IDLE_DEAD (idle thread/play_dead)
16 * | AP_OFFLINE
17 * v (IRQ-off) ,---------------^
18 * AP_ONLNE | (stop_machine)
19 * | TEARDOWN_CPU <- AP_ONLINE_IDLE
20 * | ^
21 * v |
22 * AP_ACTIVE AP_ACTIVE
23 */
24
25/*
26 * CPU hotplug states. The state machine invokes the installed state
27 * startup callbacks sequentially from CPUHP_OFFLINE + 1 to CPUHP_ONLINE
28 * during a CPU online operation. During a CPU offline operation the
29 * installed teardown callbacks are invoked in the reverse order from
30 * CPU_ONLINE - 1 down to CPUHP_OFFLINE.
31 *
32 * The state space has three sections: PREPARE, STARTING and ONLINE.
33 *
34 * PREPARE: The callbacks are invoked on a control CPU before the
35 * hotplugged CPU is started up or after the hotplugged CPU has died.
36 *
37 * STARTING: The callbacks are invoked on the hotplugged CPU from the low level
38 * hotplug startup/teardown code with interrupts disabled.
39 *
40 * ONLINE: The callbacks are invoked on the hotplugged CPU from the per CPU
41 * hotplug thread with interrupts and preemption enabled.
42 *
43 * Adding explicit states to this enum is only necessary when:
44 *
45 * 1) The state is within the STARTING section
46 *
47 * 2) The state has ordering constraints vs. other states in the
48 * same section.
49 *
50 * If neither #1 nor #2 apply, please use the dynamic state space when
51 * setting up a state by using CPUHP_BP_PREPARE_DYN or CPUHP_AP_ONLINE_DYN
52 * for the @state argument of the setup function.
53 *
54 * See Documentation/core-api/cpu_hotplug.rst for further information and
55 * examples.
56 */
57enum cpuhp_state {
58 CPUHP_INVALID = -1,
59
60 /* PREPARE section invoked on a control CPU */
61 CPUHP_OFFLINE = 0,
62 CPUHP_CREATE_THREADS,
63 CPUHP_PERF_PREPARE,
64 CPUHP_PERF_X86_PREPARE,
65 CPUHP_PERF_X86_AMD_UNCORE_PREP,
66 CPUHP_PERF_POWER,
67 CPUHP_PERF_SUPERH,
68 CPUHP_X86_HPET_DEAD,
69 CPUHP_X86_APB_DEAD,
70 CPUHP_X86_MCE_DEAD,
71 CPUHP_VIRT_NET_DEAD,
72 CPUHP_IBMVNIC_DEAD,
73 CPUHP_SLUB_DEAD,
74 CPUHP_DEBUG_OBJ_DEAD,
75 CPUHP_MM_WRITEBACK_DEAD,
76 /* Must be after CPUHP_MM_VMSTAT_DEAD */
77 CPUHP_MM_DEMOTION_DEAD,
78 CPUHP_MM_VMSTAT_DEAD,
79 CPUHP_SOFTIRQ_DEAD,
80 CPUHP_NET_MVNETA_DEAD,
81 CPUHP_CPUIDLE_DEAD,
82 CPUHP_ARM64_FPSIMD_DEAD,
83 CPUHP_ARM_OMAP_WAKE_DEAD,
84 CPUHP_IRQ_POLL_DEAD,
85 CPUHP_BLOCK_SOFTIRQ_DEAD,
86 CPUHP_BIO_DEAD,
87 CPUHP_ACPI_CPUDRV_DEAD,
88 CPUHP_S390_PFAULT_DEAD,
89 CPUHP_BLK_MQ_DEAD,
90 CPUHP_FS_BUFF_DEAD,
91 CPUHP_PRINTK_DEAD,
92 CPUHP_MM_MEMCQ_DEAD,
93 CPUHP_PERCPU_CNT_DEAD,
94 CPUHP_RADIX_DEAD,
95 CPUHP_PAGE_ALLOC,
96 CPUHP_NET_DEV_DEAD,
97 CPUHP_PCI_XGENE_DEAD,
98 CPUHP_IOMMU_IOVA_DEAD,
99 CPUHP_LUSTRE_CFS_DEAD,
100 CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
101 CPUHP_PADATA_DEAD,
102 CPUHP_AP_DTPM_CPU_DEAD,
103 CPUHP_RANDOM_PREPARE,
104 CPUHP_WORKQUEUE_PREP,
105 CPUHP_POWER_NUMA_PREPARE,
106 CPUHP_HRTIMERS_PREPARE,
107 CPUHP_PROFILE_PREPARE,
108 CPUHP_X2APIC_PREPARE,
109 CPUHP_SMPCFD_PREPARE,
110 CPUHP_RELAY_PREPARE,
111 CPUHP_SLAB_PREPARE,
112 CPUHP_MD_RAID5_PREPARE,
113 CPUHP_RCUTREE_PREP,
114 CPUHP_CPUIDLE_COUPLED_PREPARE,
115 CPUHP_POWERPC_PMAC_PREPARE,
116 CPUHP_POWERPC_MMU_CTX_PREPARE,
117 CPUHP_XEN_PREPARE,
118 CPUHP_XEN_EVTCHN_PREPARE,
119 CPUHP_ARM_SHMOBILE_SCU_PREPARE,
120 CPUHP_SH_SH3X_PREPARE,
121 CPUHP_NET_FLOW_PREPARE,
122 CPUHP_TOPOLOGY_PREPARE,
123 CPUHP_NET_IUCV_PREPARE,
124 CPUHP_ARM_BL_PREPARE,
125 CPUHP_TRACE_RB_PREPARE,
126 CPUHP_MM_ZS_PREPARE,
127 CPUHP_MM_ZSWP_MEM_PREPARE,
128 CPUHP_MM_ZSWP_POOL_PREPARE,
129 CPUHP_KVM_PPC_BOOK3S_PREPARE,
130 CPUHP_ZCOMP_PREPARE,
131 CPUHP_TIMERS_PREPARE,
132 CPUHP_MIPS_SOC_PREPARE,
133 CPUHP_BP_PREPARE_DYN,
134 CPUHP_BP_PREPARE_DYN_END = CPUHP_BP_PREPARE_DYN + 20,
135 CPUHP_BP_KICK_AP,
136 CPUHP_BRINGUP_CPU,
137
138 /*
139 * STARTING section invoked on the hotplugged CPU in low level
140 * bringup and teardown code.
141 */
142 CPUHP_AP_IDLE_DEAD,
143 CPUHP_AP_OFFLINE,
144 CPUHP_AP_CACHECTRL_STARTING,
145 CPUHP_AP_SCHED_STARTING,
146 CPUHP_AP_RCUTREE_DYING,
147 CPUHP_AP_CPU_PM_STARTING,
148 CPUHP_AP_IRQ_GIC_STARTING,
149 CPUHP_AP_IRQ_HIP04_STARTING,
150 CPUHP_AP_IRQ_APPLE_AIC_STARTING,
151 CPUHP_AP_IRQ_ARMADA_XP_STARTING,
152 CPUHP_AP_IRQ_BCM2836_STARTING,
153 CPUHP_AP_IRQ_MIPS_GIC_STARTING,
154 CPUHP_AP_IRQ_RISCV_STARTING,
155 CPUHP_AP_IRQ_LOONGARCH_STARTING,
156 CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
157 CPUHP_AP_ARM_MVEBU_COHERENCY,
158 CPUHP_AP_MICROCODE_LOADER,
159 CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
160 CPUHP_AP_PERF_X86_STARTING,
161 CPUHP_AP_PERF_X86_AMD_IBS_STARTING,
162 CPUHP_AP_PERF_X86_CQM_STARTING,
163 CPUHP_AP_PERF_X86_CSTATE_STARTING,
164 CPUHP_AP_PERF_XTENSA_STARTING,
165 CPUHP_AP_MIPS_OP_LOONGSON3_STARTING,
166 CPUHP_AP_ARM_VFP_STARTING,
167 CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
168 CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
169 CPUHP_AP_PERF_ARM_ACPI_STARTING,
170 CPUHP_AP_PERF_ARM_STARTING,
171 CPUHP_AP_PERF_RISCV_STARTING,
172 CPUHP_AP_ARM_L2X0_STARTING,
173 CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
174 CPUHP_AP_ARM_ARCH_TIMER_STARTING,
175 CPUHP_AP_ARM_ARCH_TIMER_EVTSTRM_STARTING,
176 CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
177 CPUHP_AP_JCORE_TIMER_STARTING,
178 CPUHP_AP_ARM_TWD_STARTING,
179 CPUHP_AP_QCOM_TIMER_STARTING,
180 CPUHP_AP_TEGRA_TIMER_STARTING,
181 CPUHP_AP_ARMADA_TIMER_STARTING,
182 CPUHP_AP_MARCO_TIMER_STARTING,
183 CPUHP_AP_MIPS_GIC_TIMER_STARTING,
184 CPUHP_AP_ARC_TIMER_STARTING,
185 CPUHP_AP_RISCV_TIMER_STARTING,
186 CPUHP_AP_CLINT_TIMER_STARTING,
187 CPUHP_AP_CSKY_TIMER_STARTING,
188 CPUHP_AP_TI_GP_TIMER_STARTING,
189 CPUHP_AP_HYPERV_TIMER_STARTING,
190 /* Must be the last timer callback */
191 CPUHP_AP_DUMMY_TIMER_STARTING,
192 CPUHP_AP_ARM_XEN_STARTING,
193 CPUHP_AP_ARM_XEN_RUNSTATE_STARTING,
194 CPUHP_AP_ARM_CORESIGHT_STARTING,
195 CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
196 CPUHP_AP_ARM64_ISNDEP_STARTING,
197 CPUHP_AP_SMPCFD_DYING,
198 CPUHP_AP_X86_TBOOT_DYING,
199 CPUHP_AP_ARM_CACHE_B15_RAC_DYING,
200 CPUHP_AP_ONLINE,
201 CPUHP_TEARDOWN_CPU,
202
203 /* Online section invoked on the hotplugged CPU from the hotplug thread */
204 CPUHP_AP_ONLINE_IDLE,
205 CPUHP_AP_HYPERV_ONLINE,
206 CPUHP_AP_KVM_ONLINE,
207 CPUHP_AP_SCHED_WAIT_EMPTY,
208 CPUHP_AP_SMPBOOT_THREADS,
209 CPUHP_AP_IRQ_AFFINITY_ONLINE,
210 CPUHP_AP_BLK_MQ_ONLINE,
211 CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
212 CPUHP_AP_X86_INTEL_EPB_ONLINE,
213 CPUHP_AP_PERF_ONLINE,
214 CPUHP_AP_PERF_X86_ONLINE,
215 CPUHP_AP_PERF_X86_UNCORE_ONLINE,
216 CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE,
217 CPUHP_AP_PERF_X86_AMD_POWER_ONLINE,
218 CPUHP_AP_PERF_X86_RAPL_ONLINE,
219 CPUHP_AP_PERF_X86_CQM_ONLINE,
220 CPUHP_AP_PERF_X86_CSTATE_ONLINE,
221 CPUHP_AP_PERF_X86_IDXD_ONLINE,
222 CPUHP_AP_PERF_S390_CF_ONLINE,
223 CPUHP_AP_PERF_S390_SF_ONLINE,
224 CPUHP_AP_PERF_ARM_CCI_ONLINE,
225 CPUHP_AP_PERF_ARM_CCN_ONLINE,
226 CPUHP_AP_PERF_ARM_HISI_CPA_ONLINE,
227 CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE,
228 CPUHP_AP_PERF_ARM_HISI_HHA_ONLINE,
229 CPUHP_AP_PERF_ARM_HISI_L3_ONLINE,
230 CPUHP_AP_PERF_ARM_HISI_PA_ONLINE,
231 CPUHP_AP_PERF_ARM_HISI_SLLC_ONLINE,
232 CPUHP_AP_PERF_ARM_HISI_PCIE_PMU_ONLINE,
233 CPUHP_AP_PERF_ARM_HNS3_PMU_ONLINE,
234 CPUHP_AP_PERF_ARM_L2X0_ONLINE,
235 CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
236 CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
237 CPUHP_AP_PERF_ARM_APM_XGENE_ONLINE,
238 CPUHP_AP_PERF_ARM_CAVIUM_TX2_UNCORE_ONLINE,
239 CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE,
240 CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
241 CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE,
242 CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
243 CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
244 CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE,
245 CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
246 CPUHP_AP_PERF_CSKY_ONLINE,
247 CPUHP_AP_WATCHDOG_ONLINE,
248 CPUHP_AP_WORKQUEUE_ONLINE,
249 CPUHP_AP_RANDOM_ONLINE,
250 CPUHP_AP_RCUTREE_ONLINE,
251 CPUHP_AP_BASE_CACHEINFO_ONLINE,
252 CPUHP_AP_ONLINE_DYN,
253 CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30,
254 /* Must be after CPUHP_AP_ONLINE_DYN for node_states[N_CPU] update */
255 CPUHP_AP_MM_DEMOTION_ONLINE,
256 CPUHP_AP_X86_HPET_ONLINE,
257 CPUHP_AP_X86_KVM_CLK_ONLINE,
258 CPUHP_AP_ACTIVE,
259 CPUHP_ONLINE,
260};
261
262int __cpuhp_setup_state(enum cpuhp_state state, const char *name, bool invoke,
263 int (*startup)(unsigned int cpu),
264 int (*teardown)(unsigned int cpu), bool multi_instance);
265
266int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, const char *name,
267 bool invoke,
268 int (*startup)(unsigned int cpu),
269 int (*teardown)(unsigned int cpu),
270 bool multi_instance);
271/**
272 * cpuhp_setup_state - Setup hotplug state callbacks with calling the @startup
273 * callback
274 * @state: The state for which the calls are installed
275 * @name: Name of the callback (will be used in debug output)
276 * @startup: startup callback function or NULL if not required
277 * @teardown: teardown callback function or NULL if not required
278 *
279 * Installs the callback functions and invokes the @startup callback on
280 * the online cpus which have already reached the @state.
281 */
282static inline int cpuhp_setup_state(enum cpuhp_state state,
283 const char *name,
284 int (*startup)(unsigned int cpu),
285 int (*teardown)(unsigned int cpu))
286{
287 return __cpuhp_setup_state(state, name, invoke: true, startup, teardown, multi_instance: false);
288}
289
290/**
291 * cpuhp_setup_state_cpuslocked - Setup hotplug state callbacks with calling
292 * @startup callback from a cpus_read_lock()
293 * held region
294 * @state: The state for which the calls are installed
295 * @name: Name of the callback (will be used in debug output)
296 * @startup: startup callback function or NULL if not required
297 * @teardown: teardown callback function or NULL if not required
298 *
299 * Same as cpuhp_setup_state() except that it must be invoked from within a
300 * cpus_read_lock() held region.
301 */
302static inline int cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
303 const char *name,
304 int (*startup)(unsigned int cpu),
305 int (*teardown)(unsigned int cpu))
306{
307 return __cpuhp_setup_state_cpuslocked(state, name, invoke: true, startup,
308 teardown, multi_instance: false);
309}
310
311/**
312 * cpuhp_setup_state_nocalls - Setup hotplug state callbacks without calling the
313 * @startup callback
314 * @state: The state for which the calls are installed
315 * @name: Name of the callback.
316 * @startup: startup callback function or NULL if not required
317 * @teardown: teardown callback function or NULL if not required
318 *
319 * Same as cpuhp_setup_state() except that the @startup callback is not
320 * invoked during installation. NOP if SMP=n or HOTPLUG_CPU=n.
321 */
322static inline int cpuhp_setup_state_nocalls(enum cpuhp_state state,
323 const char *name,
324 int (*startup)(unsigned int cpu),
325 int (*teardown)(unsigned int cpu))
326{
327 return __cpuhp_setup_state(state, name, invoke: false, startup, teardown,
328 multi_instance: false);
329}
330
331/**
332 * cpuhp_setup_state_nocalls_cpuslocked - Setup hotplug state callbacks without
333 * invoking the @startup callback from
334 * a cpus_read_lock() held region
335 * callbacks
336 * @state: The state for which the calls are installed
337 * @name: Name of the callback.
338 * @startup: startup callback function or NULL if not required
339 * @teardown: teardown callback function or NULL if not required
340 *
341 * Same as cpuhp_setup_state_nocalls() except that it must be invoked from
342 * within a cpus_read_lock() held region.
343 */
344static inline int cpuhp_setup_state_nocalls_cpuslocked(enum cpuhp_state state,
345 const char *name,
346 int (*startup)(unsigned int cpu),
347 int (*teardown)(unsigned int cpu))
348{
349 return __cpuhp_setup_state_cpuslocked(state, name, invoke: false, startup,
350 teardown, multi_instance: false);
351}
352
353/**
354 * cpuhp_setup_state_multi - Add callbacks for multi state
355 * @state: The state for which the calls are installed
356 * @name: Name of the callback.
357 * @startup: startup callback function or NULL if not required
358 * @teardown: teardown callback function or NULL if not required
359 *
360 * Sets the internal multi_instance flag and prepares a state to work as a multi
361 * instance callback. No callbacks are invoked at this point. The callbacks are
362 * invoked once an instance for this state are registered via
363 * cpuhp_state_add_instance() or cpuhp_state_add_instance_nocalls()
364 */
365static inline int cpuhp_setup_state_multi(enum cpuhp_state state,
366 const char *name,
367 int (*startup)(unsigned int cpu,
368 struct hlist_node *node),
369 int (*teardown)(unsigned int cpu,
370 struct hlist_node *node))
371{
372 return __cpuhp_setup_state(state, name, invoke: false,
373 startup: (void *) startup,
374 teardown: (void *) teardown, multi_instance: true);
375}
376
377int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
378 bool invoke);
379int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state,
380 struct hlist_node *node, bool invoke);
381
382/**
383 * cpuhp_state_add_instance - Add an instance for a state and invoke startup
384 * callback.
385 * @state: The state for which the instance is installed
386 * @node: The node for this individual state.
387 *
388 * Installs the instance for the @state and invokes the registered startup
389 * callback on the online cpus which have already reached the @state. The
390 * @state must have been earlier marked as multi-instance by
391 * cpuhp_setup_state_multi().
392 */
393static inline int cpuhp_state_add_instance(enum cpuhp_state state,
394 struct hlist_node *node)
395{
396 return __cpuhp_state_add_instance(state, node, invoke: true);
397}
398
399/**
400 * cpuhp_state_add_instance_nocalls - Add an instance for a state without
401 * invoking the startup callback.
402 * @state: The state for which the instance is installed
403 * @node: The node for this individual state.
404 *
405 * Installs the instance for the @state. The @state must have been earlier
406 * marked as multi-instance by cpuhp_setup_state_multi. NOP if SMP=n or
407 * HOTPLUG_CPU=n.
408 */
409static inline int cpuhp_state_add_instance_nocalls(enum cpuhp_state state,
410 struct hlist_node *node)
411{
412 return __cpuhp_state_add_instance(state, node, invoke: false);
413}
414
415/**
416 * cpuhp_state_add_instance_nocalls_cpuslocked - Add an instance for a state
417 * without invoking the startup
418 * callback from a cpus_read_lock()
419 * held region.
420 * @state: The state for which the instance is installed
421 * @node: The node for this individual state.
422 *
423 * Same as cpuhp_state_add_instance_nocalls() except that it must be
424 * invoked from within a cpus_read_lock() held region.
425 */
426static inline int
427cpuhp_state_add_instance_nocalls_cpuslocked(enum cpuhp_state state,
428 struct hlist_node *node)
429{
430 return __cpuhp_state_add_instance_cpuslocked(state, node, invoke: false);
431}
432
433void __cpuhp_remove_state(enum cpuhp_state state, bool invoke);
434void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke);
435
436/**
437 * cpuhp_remove_state - Remove hotplug state callbacks and invoke the teardown
438 * @state: The state for which the calls are removed
439 *
440 * Removes the callback functions and invokes the teardown callback on
441 * the online cpus which have already reached the @state.
442 */
443static inline void cpuhp_remove_state(enum cpuhp_state state)
444{
445 __cpuhp_remove_state(state, invoke: true);
446}
447
448/**
449 * cpuhp_remove_state_nocalls - Remove hotplug state callbacks without invoking
450 * the teardown callback
451 * @state: The state for which the calls are removed
452 */
453static inline void cpuhp_remove_state_nocalls(enum cpuhp_state state)
454{
455 __cpuhp_remove_state(state, invoke: false);
456}
457
458/**
459 * cpuhp_remove_state_nocalls_cpuslocked - Remove hotplug state callbacks without invoking
460 * teardown from a cpus_read_lock() held region.
461 * @state: The state for which the calls are removed
462 *
463 * Same as cpuhp_remove_state nocalls() except that it must be invoked
464 * from within a cpus_read_lock() held region.
465 */
466static inline void cpuhp_remove_state_nocalls_cpuslocked(enum cpuhp_state state)
467{
468 __cpuhp_remove_state_cpuslocked(state, invoke: false);
469}
470
471/**
472 * cpuhp_remove_multi_state - Remove hotplug multi state callback
473 * @state: The state for which the calls are removed
474 *
475 * Removes the callback functions from a multi state. This is the reverse of
476 * cpuhp_setup_state_multi(). All instances should have been removed before
477 * invoking this function.
478 */
479static inline void cpuhp_remove_multi_state(enum cpuhp_state state)
480{
481 __cpuhp_remove_state(state, invoke: false);
482}
483
484int __cpuhp_state_remove_instance(enum cpuhp_state state,
485 struct hlist_node *node, bool invoke);
486
487/**
488 * cpuhp_state_remove_instance - Remove hotplug instance from state and invoke
489 * the teardown callback
490 * @state: The state from which the instance is removed
491 * @node: The node for this individual state.
492 *
493 * Removes the instance and invokes the teardown callback on the online cpus
494 * which have already reached @state.
495 */
496static inline int cpuhp_state_remove_instance(enum cpuhp_state state,
497 struct hlist_node *node)
498{
499 return __cpuhp_state_remove_instance(state, node, invoke: true);
500}
501
502/**
503 * cpuhp_state_remove_instance_nocalls - Remove hotplug instance from state
504 * without invoking the teardown callback
505 * @state: The state from which the instance is removed
506 * @node: The node for this individual state.
507 *
508 * Removes the instance without invoking the teardown callback.
509 */
510static inline int cpuhp_state_remove_instance_nocalls(enum cpuhp_state state,
511 struct hlist_node *node)
512{
513 return __cpuhp_state_remove_instance(state, node, invoke: false);
514}
515
516#ifdef CONFIG_SMP
517void cpuhp_online_idle(enum cpuhp_state state);
518#else
519static inline void cpuhp_online_idle(enum cpuhp_state state) { }
520#endif
521
522struct task_struct;
523
524void cpuhp_ap_sync_alive(void);
525void arch_cpuhp_sync_state_poll(void);
526void arch_cpuhp_cleanup_kick_cpu(unsigned int cpu);
527int arch_cpuhp_kick_ap_alive(unsigned int cpu, struct task_struct *tidle);
528bool arch_cpuhp_init_parallel_bringup(void);
529
530#ifdef CONFIG_HOTPLUG_CORE_SYNC_DEAD
531void cpuhp_ap_report_dead(void);
532void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu);
533#else
534static inline void cpuhp_ap_report_dead(void) { }
535static inline void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) { }
536#endif
537
538#endif
539

source code of linux/include/linux/cpuhotplug.h