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_PREPARE_DYN or CPUHP_PREPARE_ONLINE 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 */ 57 enum 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_SLUB_DEAD, 73 CPUHP_DEBUG_OBJ_DEAD, 74 CPUHP_MM_WRITEBACK_DEAD, 75 /* Must be after CPUHP_MM_VMSTAT_DEAD */ 76 CPUHP_MM_DEMOTION_DEAD, 77 CPUHP_MM_VMSTAT_DEAD, 78 CPUHP_SOFTIRQ_DEAD, 79 CPUHP_NET_MVNETA_DEAD, 80 CPUHP_CPUIDLE_DEAD, 81 CPUHP_ARM64_FPSIMD_DEAD, 82 CPUHP_ARM_OMAP_WAKE_DEAD, 83 CPUHP_IRQ_POLL_DEAD, 84 CPUHP_BLOCK_SOFTIRQ_DEAD, 85 CPUHP_BIO_DEAD, 86 CPUHP_ACPI_CPUDRV_DEAD, 87 CPUHP_S390_PFAULT_DEAD, 88 CPUHP_BLK_MQ_DEAD, 89 CPUHP_FS_BUFF_DEAD, 90 CPUHP_PRINTK_DEAD, 91 CPUHP_MM_MEMCQ_DEAD, 92 CPUHP_XFS_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_BRINGUP_CPU, 136 137 /* 138 * STARTING section invoked on the hotplugged CPU in low level 139 * bringup and teardown code. 140 */ 141 CPUHP_AP_IDLE_DEAD, 142 CPUHP_AP_OFFLINE, 143 CPUHP_AP_SCHED_STARTING, 144 CPUHP_AP_RCUTREE_DYING, 145 CPUHP_AP_CPU_PM_STARTING, 146 CPUHP_AP_IRQ_GIC_STARTING, 147 CPUHP_AP_IRQ_HIP04_STARTING, 148 CPUHP_AP_IRQ_APPLE_AIC_STARTING, 149 CPUHP_AP_IRQ_ARMADA_XP_STARTING, 150 CPUHP_AP_IRQ_BCM2836_STARTING, 151 CPUHP_AP_IRQ_MIPS_GIC_STARTING, 152 CPUHP_AP_IRQ_RISCV_STARTING, 153 CPUHP_AP_IRQ_LOONGARCH_STARTING, 154 CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING, 155 CPUHP_AP_ARM_MVEBU_COHERENCY, 156 CPUHP_AP_MICROCODE_LOADER, 157 CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING, 158 CPUHP_AP_PERF_X86_STARTING, 159 CPUHP_AP_PERF_X86_AMD_IBS_STARTING, 160 CPUHP_AP_PERF_X86_CQM_STARTING, 161 CPUHP_AP_PERF_X86_CSTATE_STARTING, 162 CPUHP_AP_PERF_XTENSA_STARTING, 163 CPUHP_AP_MIPS_OP_LOONGSON3_STARTING, 164 CPUHP_AP_ARM_SDEI_STARTING, 165 CPUHP_AP_ARM_VFP_STARTING, 166 CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING, 167 CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING, 168 CPUHP_AP_PERF_ARM_ACPI_STARTING, 169 CPUHP_AP_PERF_ARM_STARTING, 170 CPUHP_AP_PERF_RISCV_STARTING, 171 CPUHP_AP_ARM_L2X0_STARTING, 172 CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING, 173 CPUHP_AP_ARM_ARCH_TIMER_STARTING, 174 CPUHP_AP_ARM_GLOBAL_TIMER_STARTING, 175 CPUHP_AP_JCORE_TIMER_STARTING, 176 CPUHP_AP_ARM_TWD_STARTING, 177 CPUHP_AP_QCOM_TIMER_STARTING, 178 CPUHP_AP_TEGRA_TIMER_STARTING, 179 CPUHP_AP_ARMADA_TIMER_STARTING, 180 CPUHP_AP_MARCO_TIMER_STARTING, 181 CPUHP_AP_MIPS_GIC_TIMER_STARTING, 182 CPUHP_AP_ARC_TIMER_STARTING, 183 CPUHP_AP_RISCV_TIMER_STARTING, 184 CPUHP_AP_CLINT_TIMER_STARTING, 185 CPUHP_AP_CSKY_TIMER_STARTING, 186 CPUHP_AP_TI_GP_TIMER_STARTING, 187 CPUHP_AP_HYPERV_TIMER_STARTING, 188 CPUHP_AP_KVM_STARTING, 189 CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING, 190 CPUHP_AP_KVM_ARM_VGIC_STARTING, 191 CPUHP_AP_KVM_ARM_TIMER_STARTING, 192 /* Must be the last timer callback */ 193 CPUHP_AP_DUMMY_TIMER_STARTING, 194 CPUHP_AP_ARM_XEN_STARTING, 195 CPUHP_AP_ARM_CORESIGHT_STARTING, 196 CPUHP_AP_ARM_CORESIGHT_CTI_STARTING, 197 CPUHP_AP_ARM64_ISNDEP_STARTING, 198 CPUHP_AP_SMPCFD_DYING, 199 CPUHP_AP_X86_TBOOT_DYING, 200 CPUHP_AP_ARM_CACHE_B15_RAC_DYING, 201 CPUHP_AP_ONLINE, 202 CPUHP_TEARDOWN_CPU, 203 204 /* Online section invoked on the hotplugged CPU from the hotplug thread */ 205 CPUHP_AP_ONLINE_IDLE, 206 CPUHP_AP_SCHED_WAIT_EMPTY, 207 CPUHP_AP_SMPBOOT_THREADS, 208 CPUHP_AP_X86_VDSO_VMA_ONLINE, 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 }; 261 262 int __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); 265 266 int __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 */ 282 static 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, true, startup, teardown, 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 */ 302 static 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, true, startup, 308 teardown, 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 */ 322 static 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, false, startup, teardown, 328 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 */ 344 static 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, false, startup, 350 teardown, 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 */ 365 static 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, false, 373 (void *) startup, 374 (void *) teardown, true); 375 } 376 377 int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, 378 bool invoke); 379 int __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 */ 393 static inline int cpuhp_state_add_instance(enum cpuhp_state state, 394 struct hlist_node *node) 395 { 396 return __cpuhp_state_add_instance(state, node, 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 */ 409 static 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, 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 */ 426 static inline int 427 cpuhp_state_add_instance_nocalls_cpuslocked(enum cpuhp_state state, 428 struct hlist_node *node) 429 { 430 return __cpuhp_state_add_instance_cpuslocked(state, node, false); 431 } 432 433 void __cpuhp_remove_state(enum cpuhp_state state, bool invoke); 434 void __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 */ 443 static inline void cpuhp_remove_state(enum cpuhp_state state) 444 { 445 __cpuhp_remove_state(state, 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 */ 453 static inline void cpuhp_remove_state_nocalls(enum cpuhp_state state) 454 { 455 __cpuhp_remove_state(state, 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 */ 466 static inline void cpuhp_remove_state_nocalls_cpuslocked(enum cpuhp_state state) 467 { 468 __cpuhp_remove_state_cpuslocked(state, 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 */ 479 static inline void cpuhp_remove_multi_state(enum cpuhp_state state) 480 { 481 __cpuhp_remove_state(state, false); 482 } 483 484 int __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 */ 496 static inline int cpuhp_state_remove_instance(enum cpuhp_state state, 497 struct hlist_node *node) 498 { 499 return __cpuhp_state_remove_instance(state, node, 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 */ 510 static 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, false); 514 } 515 516 #ifdef CONFIG_SMP 517 void cpuhp_online_idle(enum cpuhp_state state); 518 #else 519 static inline void cpuhp_online_idle(enum cpuhp_state state) { } 520 #endif 521 522 #endif 523