smp.c 17 KB

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  1. /*
  2. * linux/arch/arm/kernel/smp.c
  3. *
  4. * Copyright (C) 2002 ARM Limited, All Rights Reserved.
  5. *
  6. * This program is free software; you can redistribute it and/or modify
  7. * it under the terms of the GNU General Public License version 2 as
  8. * published by the Free Software Foundation.
  9. */
  10. #include <linux/module.h>
  11. #include <linux/delay.h>
  12. #include <linux/init.h>
  13. #include <linux/spinlock.h>
  14. #include <linux/sched.h>
  15. #include <linux/interrupt.h>
  16. #include <linux/cache.h>
  17. #include <linux/profile.h>
  18. #include <linux/errno.h>
  19. #include <linux/mm.h>
  20. #include <linux/err.h>
  21. #include <linux/cpu.h>
  22. #include <linux/seq_file.h>
  23. #include <linux/irq.h>
  24. #include <linux/percpu.h>
  25. #include <linux/clockchips.h>
  26. #include <linux/completion.h>
  27. #include <linux/cpufreq.h>
  28. #include <linux/atomic.h>
  29. #include <asm/smp.h>
  30. #include <asm/cacheflush.h>
  31. #include <asm/cpu.h>
  32. #include <asm/cputype.h>
  33. #include <asm/exception.h>
  34. #include <asm/idmap.h>
  35. #include <asm/topology.h>
  36. #include <asm/mmu_context.h>
  37. #include <asm/pgtable.h>
  38. #include <asm/pgalloc.h>
  39. #include <asm/processor.h>
  40. #include <asm/sections.h>
  41. #include <asm/tlbflush.h>
  42. #include <asm/ptrace.h>
  43. #include <asm/localtimer.h>
  44. #include <asm/smp_plat.h>
  45. #include <asm/virt.h>
  46. #include <asm/mach/arch.h>
  47. /*
  48. * as from 2.5, kernels no longer have an init_tasks structure
  49. * so we need some other way of telling a new secondary core
  50. * where to place its SVC stack
  51. */
  52. struct secondary_data secondary_data;
  53. /*
  54. * control for which core is the next to come out of the secondary
  55. * boot "holding pen"
  56. */
  57. volatile int __cpuinitdata pen_release = -1;
  58. enum ipi_msg_type {
  59. IPI_WAKEUP,
  60. IPI_TIMER,
  61. IPI_RESCHEDULE,
  62. IPI_CALL_FUNC,
  63. IPI_CALL_FUNC_SINGLE,
  64. IPI_CPU_STOP,
  65. };
  66. static DECLARE_COMPLETION(cpu_running);
  67. static struct smp_operations smp_ops;
  68. void __init smp_set_ops(struct smp_operations *ops)
  69. {
  70. if (ops)
  71. smp_ops = *ops;
  72. };
  73. int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
  74. {
  75. int ret;
  76. /*
  77. * We need to tell the secondary core where to find
  78. * its stack and the page tables.
  79. */
  80. secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
  81. secondary_data.pgdir = virt_to_phys(idmap_pgd);
  82. secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
  83. __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
  84. outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
  85. /*
  86. * Now bring the CPU into our world.
  87. */
  88. ret = boot_secondary(cpu, idle);
  89. if (ret == 0) {
  90. /*
  91. * CPU was successfully started, wait for it
  92. * to come online or time out.
  93. */
  94. wait_for_completion_timeout(&cpu_running,
  95. msecs_to_jiffies(1000));
  96. if (!cpu_online(cpu)) {
  97. pr_crit("CPU%u: failed to come online\n", cpu);
  98. ret = -EIO;
  99. }
  100. } else {
  101. pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
  102. }
  103. secondary_data.stack = NULL;
  104. secondary_data.pgdir = 0;
  105. return ret;
  106. }
  107. /* platform specific SMP operations */
  108. void __init smp_init_cpus(void)
  109. {
  110. if (smp_ops.smp_init_cpus)
  111. smp_ops.smp_init_cpus();
  112. }
  113. int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
  114. {
  115. if (smp_ops.smp_boot_secondary)
  116. return smp_ops.smp_boot_secondary(cpu, idle);
  117. return -ENOSYS;
  118. }
  119. #ifdef CONFIG_HOTPLUG_CPU
  120. static void percpu_timer_stop(void);
  121. static int platform_cpu_kill(unsigned int cpu)
  122. {
  123. if (smp_ops.cpu_kill)
  124. return smp_ops.cpu_kill(cpu);
  125. return 1;
  126. }
  127. static int platform_cpu_disable(unsigned int cpu)
  128. {
  129. if (smp_ops.cpu_disable)
  130. return smp_ops.cpu_disable(cpu);
  131. /*
  132. * By default, allow disabling all CPUs except the first one,
  133. * since this is special on a lot of platforms, e.g. because
  134. * of clock tick interrupts.
  135. */
  136. return cpu == 0 ? -EPERM : 0;
  137. }
  138. /*
  139. * __cpu_disable runs on the processor to be shutdown.
  140. */
  141. int __cpuinit __cpu_disable(void)
  142. {
  143. unsigned int cpu = smp_processor_id();
  144. int ret;
  145. ret = platform_cpu_disable(cpu);
  146. if (ret)
  147. return ret;
  148. /*
  149. * Take this CPU offline. Once we clear this, we can't return,
  150. * and we must not schedule until we're ready to give up the cpu.
  151. */
  152. set_cpu_online(cpu, false);
  153. /*
  154. * OK - migrate IRQs away from this CPU
  155. */
  156. migrate_irqs();
  157. /*
  158. * Stop the local timer for this CPU.
  159. */
  160. percpu_timer_stop();
  161. /*
  162. * Flush user cache and TLB mappings, and then remove this CPU
  163. * from the vm mask set of all processes.
  164. *
  165. * Caches are flushed to the Level of Unification Inner Shareable
  166. * to write-back dirty lines to unified caches shared by all CPUs.
  167. */
  168. flush_cache_louis();
  169. local_flush_tlb_all();
  170. clear_tasks_mm_cpumask(cpu);
  171. return 0;
  172. }
  173. static DECLARE_COMPLETION(cpu_died);
  174. /*
  175. * called on the thread which is asking for a CPU to be shutdown -
  176. * waits until shutdown has completed, or it is timed out.
  177. */
  178. void __cpuinit __cpu_die(unsigned int cpu)
  179. {
  180. if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
  181. pr_err("CPU%u: cpu didn't die\n", cpu);
  182. return;
  183. }
  184. printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
  185. /*
  186. * platform_cpu_kill() is generally expected to do the powering off
  187. * and/or cutting of clocks to the dying CPU. Optionally, this may
  188. * be done by the CPU which is dying in preference to supporting
  189. * this call, but that means there is _no_ synchronisation between
  190. * the requesting CPU and the dying CPU actually losing power.
  191. */
  192. if (!platform_cpu_kill(cpu))
  193. printk("CPU%u: unable to kill\n", cpu);
  194. }
  195. /*
  196. * Called from the idle thread for the CPU which has been shutdown.
  197. *
  198. * Note that we disable IRQs here, but do not re-enable them
  199. * before returning to the caller. This is also the behaviour
  200. * of the other hotplug-cpu capable cores, so presumably coming
  201. * out of idle fixes this.
  202. */
  203. void __ref cpu_die(void)
  204. {
  205. unsigned int cpu = smp_processor_id();
  206. idle_task_exit();
  207. local_irq_disable();
  208. /*
  209. * Flush the data out of the L1 cache for this CPU. This must be
  210. * before the completion to ensure that data is safely written out
  211. * before platform_cpu_kill() gets called - which may disable
  212. * *this* CPU and power down its cache.
  213. */
  214. flush_cache_louis();
  215. /*
  216. * Tell __cpu_die() that this CPU is now safe to dispose of. Once
  217. * this returns, power and/or clocks can be removed at any point
  218. * from this CPU and its cache by platform_cpu_kill().
  219. */
  220. RCU_NONIDLE(complete(&cpu_died));
  221. /*
  222. * Ensure that the cache lines associated with that completion are
  223. * written out. This covers the case where _this_ CPU is doing the
  224. * powering down, to ensure that the completion is visible to the
  225. * CPU waiting for this one.
  226. */
  227. flush_cache_louis();
  228. /*
  229. * The actual CPU shutdown procedure is at least platform (if not
  230. * CPU) specific. This may remove power, or it may simply spin.
  231. *
  232. * Platforms are generally expected *NOT* to return from this call,
  233. * although there are some which do because they have no way to
  234. * power down the CPU. These platforms are the _only_ reason we
  235. * have a return path which uses the fragment of assembly below.
  236. *
  237. * The return path should not be used for platforms which can
  238. * power off the CPU.
  239. */
  240. if (smp_ops.cpu_die)
  241. smp_ops.cpu_die(cpu);
  242. /*
  243. * Do not return to the idle loop - jump back to the secondary
  244. * cpu initialisation. There's some initialisation which needs
  245. * to be repeated to undo the effects of taking the CPU offline.
  246. */
  247. __asm__("mov sp, %0\n"
  248. " mov fp, #0\n"
  249. " b secondary_start_kernel"
  250. :
  251. : "r" (task_stack_page(current) + THREAD_SIZE - 8));
  252. }
  253. #endif /* CONFIG_HOTPLUG_CPU */
  254. /*
  255. * Called by both boot and secondaries to move global data into
  256. * per-processor storage.
  257. */
  258. static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
  259. {
  260. struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
  261. cpu_info->loops_per_jiffy = loops_per_jiffy;
  262. cpu_info->cpuid = read_cpuid_id();
  263. store_cpu_topology(cpuid);
  264. }
  265. static void percpu_timer_setup(void);
  266. /*
  267. * This is the secondary CPU boot entry. We're using this CPUs
  268. * idle thread stack, but a set of temporary page tables.
  269. */
  270. asmlinkage void __cpuinit secondary_start_kernel(void)
  271. {
  272. struct mm_struct *mm = &init_mm;
  273. unsigned int cpu;
  274. /*
  275. * The identity mapping is uncached (strongly ordered), so
  276. * switch away from it before attempting any exclusive accesses.
  277. */
  278. cpu_switch_mm(mm->pgd, mm);
  279. local_flush_bp_all();
  280. enter_lazy_tlb(mm, current);
  281. local_flush_tlb_all();
  282. /*
  283. * All kernel threads share the same mm context; grab a
  284. * reference and switch to it.
  285. */
  286. cpu = smp_processor_id();
  287. atomic_inc(&mm->mm_count);
  288. current->active_mm = mm;
  289. cpumask_set_cpu(cpu, mm_cpumask(mm));
  290. cpu_init();
  291. printk("CPU%u: Booted secondary processor\n", cpu);
  292. preempt_disable();
  293. trace_hardirqs_off();
  294. /*
  295. * Give the platform a chance to do its own initialisation.
  296. */
  297. if (smp_ops.smp_secondary_init)
  298. smp_ops.smp_secondary_init(cpu);
  299. notify_cpu_starting(cpu);
  300. calibrate_delay();
  301. smp_store_cpu_info(cpu);
  302. /*
  303. * OK, now it's safe to let the boot CPU continue. Wait for
  304. * the CPU migration code to notice that the CPU is online
  305. * before we continue - which happens after __cpu_up returns.
  306. */
  307. set_cpu_online(cpu, true);
  308. complete(&cpu_running);
  309. /*
  310. * Setup the percpu timer for this CPU.
  311. */
  312. percpu_timer_setup();
  313. local_irq_enable();
  314. local_fiq_enable();
  315. /*
  316. * OK, it's off to the idle thread for us
  317. */
  318. cpu_startup_entry(CPUHP_ONLINE);
  319. }
  320. void __init smp_cpus_done(unsigned int max_cpus)
  321. {
  322. int cpu;
  323. unsigned long bogosum = 0;
  324. for_each_online_cpu(cpu)
  325. bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
  326. printk(KERN_INFO "SMP: Total of %d processors activated "
  327. "(%lu.%02lu BogoMIPS).\n",
  328. num_online_cpus(),
  329. bogosum / (500000/HZ),
  330. (bogosum / (5000/HZ)) % 100);
  331. hyp_mode_check();
  332. }
  333. void __init smp_prepare_boot_cpu(void)
  334. {
  335. set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
  336. }
  337. void __init smp_prepare_cpus(unsigned int max_cpus)
  338. {
  339. unsigned int ncores = num_possible_cpus();
  340. init_cpu_topology();
  341. smp_store_cpu_info(smp_processor_id());
  342. /*
  343. * are we trying to boot more cores than exist?
  344. */
  345. if (max_cpus > ncores)
  346. max_cpus = ncores;
  347. if (ncores > 1 && max_cpus) {
  348. /*
  349. * Enable the local timer or broadcast device for the
  350. * boot CPU, but only if we have more than one CPU.
  351. */
  352. percpu_timer_setup();
  353. /*
  354. * Initialise the present map, which describes the set of CPUs
  355. * actually populated at the present time. A platform should
  356. * re-initialize the map in the platforms smp_prepare_cpus()
  357. * if present != possible (e.g. physical hotplug).
  358. */
  359. init_cpu_present(cpu_possible_mask);
  360. /*
  361. * Initialise the SCU if there are more than one CPU
  362. * and let them know where to start.
  363. */
  364. if (smp_ops.smp_prepare_cpus)
  365. smp_ops.smp_prepare_cpus(max_cpus);
  366. }
  367. }
  368. static void (*smp_cross_call)(const struct cpumask *, unsigned int);
  369. void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
  370. {
  371. if (!smp_cross_call)
  372. smp_cross_call = fn;
  373. }
  374. void arch_send_call_function_ipi_mask(const struct cpumask *mask)
  375. {
  376. smp_cross_call(mask, IPI_CALL_FUNC);
  377. }
  378. void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
  379. {
  380. smp_cross_call(mask, IPI_WAKEUP);
  381. }
  382. void arch_send_call_function_single_ipi(int cpu)
  383. {
  384. smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
  385. }
  386. static const char *ipi_types[NR_IPI] = {
  387. #define S(x,s) [x] = s
  388. S(IPI_WAKEUP, "CPU wakeup interrupts"),
  389. S(IPI_TIMER, "Timer broadcast interrupts"),
  390. S(IPI_RESCHEDULE, "Rescheduling interrupts"),
  391. S(IPI_CALL_FUNC, "Function call interrupts"),
  392. S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
  393. S(IPI_CPU_STOP, "CPU stop interrupts"),
  394. };
  395. void show_ipi_list(struct seq_file *p, int prec)
  396. {
  397. unsigned int cpu, i;
  398. for (i = 0; i < NR_IPI; i++) {
  399. seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
  400. for_each_online_cpu(cpu)
  401. seq_printf(p, "%10u ",
  402. __get_irq_stat(cpu, ipi_irqs[i]));
  403. seq_printf(p, " %s\n", ipi_types[i]);
  404. }
  405. }
  406. u64 smp_irq_stat_cpu(unsigned int cpu)
  407. {
  408. u64 sum = 0;
  409. int i;
  410. for (i = 0; i < NR_IPI; i++)
  411. sum += __get_irq_stat(cpu, ipi_irqs[i]);
  412. return sum;
  413. }
  414. /*
  415. * Timer (local or broadcast) support
  416. */
  417. static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
  418. #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  419. void tick_broadcast(const struct cpumask *mask)
  420. {
  421. smp_cross_call(mask, IPI_TIMER);
  422. }
  423. #endif
  424. static void broadcast_timer_set_mode(enum clock_event_mode mode,
  425. struct clock_event_device *evt)
  426. {
  427. }
  428. static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
  429. {
  430. evt->name = "dummy_timer";
  431. evt->features = CLOCK_EVT_FEAT_ONESHOT |
  432. CLOCK_EVT_FEAT_PERIODIC |
  433. CLOCK_EVT_FEAT_DUMMY;
  434. evt->rating = 100;
  435. evt->mult = 1;
  436. evt->set_mode = broadcast_timer_set_mode;
  437. clockevents_register_device(evt);
  438. }
  439. static struct local_timer_ops *lt_ops;
  440. #ifdef CONFIG_LOCAL_TIMERS
  441. int local_timer_register(struct local_timer_ops *ops)
  442. {
  443. if (!is_smp() || !setup_max_cpus)
  444. return -ENXIO;
  445. if (lt_ops)
  446. return -EBUSY;
  447. lt_ops = ops;
  448. return 0;
  449. }
  450. #endif
  451. static void __cpuinit percpu_timer_setup(void)
  452. {
  453. unsigned int cpu = smp_processor_id();
  454. struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
  455. evt->cpumask = cpumask_of(cpu);
  456. if (!lt_ops || lt_ops->setup(evt))
  457. broadcast_timer_setup(evt);
  458. }
  459. #ifdef CONFIG_HOTPLUG_CPU
  460. /*
  461. * The generic clock events code purposely does not stop the local timer
  462. * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
  463. * manually here.
  464. */
  465. static void percpu_timer_stop(void)
  466. {
  467. unsigned int cpu = smp_processor_id();
  468. struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
  469. if (lt_ops)
  470. lt_ops->stop(evt);
  471. }
  472. #endif
  473. static DEFINE_RAW_SPINLOCK(stop_lock);
  474. /*
  475. * ipi_cpu_stop - handle IPI from smp_send_stop()
  476. */
  477. static void ipi_cpu_stop(unsigned int cpu)
  478. {
  479. if (system_state == SYSTEM_BOOTING ||
  480. system_state == SYSTEM_RUNNING) {
  481. raw_spin_lock(&stop_lock);
  482. printk(KERN_CRIT "CPU%u: stopping\n", cpu);
  483. dump_stack();
  484. raw_spin_unlock(&stop_lock);
  485. }
  486. set_cpu_online(cpu, false);
  487. local_fiq_disable();
  488. local_irq_disable();
  489. while (1)
  490. cpu_relax();
  491. }
  492. /*
  493. * Main handler for inter-processor interrupts
  494. */
  495. asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
  496. {
  497. handle_IPI(ipinr, regs);
  498. }
  499. void handle_IPI(int ipinr, struct pt_regs *regs)
  500. {
  501. unsigned int cpu = smp_processor_id();
  502. struct pt_regs *old_regs = set_irq_regs(regs);
  503. if (ipinr < NR_IPI)
  504. __inc_irq_stat(cpu, ipi_irqs[ipinr]);
  505. switch (ipinr) {
  506. case IPI_WAKEUP:
  507. break;
  508. #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  509. case IPI_TIMER:
  510. irq_enter();
  511. tick_receive_broadcast();
  512. irq_exit();
  513. break;
  514. #endif
  515. case IPI_RESCHEDULE:
  516. scheduler_ipi();
  517. break;
  518. case IPI_CALL_FUNC:
  519. irq_enter();
  520. generic_smp_call_function_interrupt();
  521. irq_exit();
  522. break;
  523. case IPI_CALL_FUNC_SINGLE:
  524. irq_enter();
  525. generic_smp_call_function_single_interrupt();
  526. irq_exit();
  527. break;
  528. case IPI_CPU_STOP:
  529. irq_enter();
  530. ipi_cpu_stop(cpu);
  531. irq_exit();
  532. break;
  533. default:
  534. printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
  535. cpu, ipinr);
  536. break;
  537. }
  538. set_irq_regs(old_regs);
  539. }
  540. void smp_send_reschedule(int cpu)
  541. {
  542. smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
  543. }
  544. #ifdef CONFIG_HOTPLUG_CPU
  545. static void smp_kill_cpus(cpumask_t *mask)
  546. {
  547. unsigned int cpu;
  548. for_each_cpu(cpu, mask)
  549. platform_cpu_kill(cpu);
  550. }
  551. #else
  552. static void smp_kill_cpus(cpumask_t *mask) { }
  553. #endif
  554. void smp_send_stop(void)
  555. {
  556. unsigned long timeout;
  557. struct cpumask mask;
  558. cpumask_copy(&mask, cpu_online_mask);
  559. cpumask_clear_cpu(smp_processor_id(), &mask);
  560. if (!cpumask_empty(&mask))
  561. smp_cross_call(&mask, IPI_CPU_STOP);
  562. /* Wait up to one second for other CPUs to stop */
  563. timeout = USEC_PER_SEC;
  564. while (num_online_cpus() > 1 && timeout--)
  565. udelay(1);
  566. if (num_online_cpus() > 1)
  567. pr_warning("SMP: failed to stop secondary CPUs\n");
  568. smp_kill_cpus(&mask);
  569. }
  570. /*
  571. * not supported here
  572. */
  573. int setup_profiling_timer(unsigned int multiplier)
  574. {
  575. return -EINVAL;
  576. }
  577. #ifdef CONFIG_CPU_FREQ
  578. static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
  579. static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
  580. static unsigned long global_l_p_j_ref;
  581. static unsigned long global_l_p_j_ref_freq;
  582. static int cpufreq_callback(struct notifier_block *nb,
  583. unsigned long val, void *data)
  584. {
  585. struct cpufreq_freqs *freq = data;
  586. int cpu = freq->cpu;
  587. if (freq->flags & CPUFREQ_CONST_LOOPS)
  588. return NOTIFY_OK;
  589. if (!per_cpu(l_p_j_ref, cpu)) {
  590. per_cpu(l_p_j_ref, cpu) =
  591. per_cpu(cpu_data, cpu).loops_per_jiffy;
  592. per_cpu(l_p_j_ref_freq, cpu) = freq->old;
  593. if (!global_l_p_j_ref) {
  594. global_l_p_j_ref = loops_per_jiffy;
  595. global_l_p_j_ref_freq = freq->old;
  596. }
  597. }
  598. if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
  599. (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
  600. (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
  601. loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
  602. global_l_p_j_ref_freq,
  603. freq->new);
  604. per_cpu(cpu_data, cpu).loops_per_jiffy =
  605. cpufreq_scale(per_cpu(l_p_j_ref, cpu),
  606. per_cpu(l_p_j_ref_freq, cpu),
  607. freq->new);
  608. }
  609. return NOTIFY_OK;
  610. }
  611. static struct notifier_block cpufreq_notifier = {
  612. .notifier_call = cpufreq_callback,
  613. };
  614. static int __init register_cpufreq_notifier(void)
  615. {
  616. return cpufreq_register_notifier(&cpufreq_notifier,
  617. CPUFREQ_TRANSITION_NOTIFIER);
  618. }
  619. core_initcall(register_cpufreq_notifier);
  620. #endif