Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
[linux-2.6.git] / arch / powerpc / kernel / smp.c
1 /*
2  * SMP support for ppc.
3  *
4  * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
5  * deal of code from the sparc and intel versions.
6  *
7  * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
8  *
9  * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
10  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
11  *
12  *      This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  */
17
18 #undef DEBUG
19
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/sched.h>
23 #include <linux/smp.h>
24 #include <linux/interrupt.h>
25 #include <linux/delay.h>
26 #include <linux/init.h>
27 #include <linux/spinlock.h>
28 #include <linux/cache.h>
29 #include <linux/err.h>
30 #include <linux/sysdev.h>
31 #include <linux/cpu.h>
32 #include <linux/notifier.h>
33 #include <linux/topology.h>
34
35 #include <asm/ptrace.h>
36 #include <asm/atomic.h>
37 #include <asm/irq.h>
38 #include <asm/page.h>
39 #include <asm/pgtable.h>
40 #include <asm/prom.h>
41 #include <asm/smp.h>
42 #include <asm/time.h>
43 #include <asm/machdep.h>
44 #include <asm/cputhreads.h>
45 #include <asm/cputable.h>
46 #include <asm/system.h>
47 #include <asm/mpic.h>
48 #include <asm/vdso_datapage.h>
49 #ifdef CONFIG_PPC64
50 #include <asm/paca.h>
51 #endif
52
53 #ifdef DEBUG
54 #include <asm/udbg.h>
55 #define DBG(fmt...) udbg_printf(fmt)
56 #else
57 #define DBG(fmt...)
58 #endif
59
60
61 /* Store all idle threads, this can be reused instead of creating
62 * a new thread. Also avoids complicated thread destroy functionality
63 * for idle threads.
64 */
65 #ifdef CONFIG_HOTPLUG_CPU
66 /*
67  * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
68  * removed after init for !CONFIG_HOTPLUG_CPU.
69  */
70 static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
71 #define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
72 #define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
73 #else
74 static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
75 #define get_idle_for_cpu(x)      (idle_thread_array[(x)])
76 #define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
77 #endif
78
79 struct thread_info *secondary_ti;
80
81 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
82 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
83
84 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
85 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
86
87 /* SMP operations for this machine */
88 struct smp_ops_t *smp_ops;
89
90 /* Can't be static due to PowerMac hackery */
91 volatile unsigned int cpu_callin_map[NR_CPUS];
92
93 int smt_enabled_at_boot = 1;
94
95 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
96
97 #ifdef CONFIG_PPC64
98 int __devinit smp_generic_kick_cpu(int nr)
99 {
100         BUG_ON(nr < 0 || nr >= NR_CPUS);
101
102         /*
103          * The processor is currently spinning, waiting for the
104          * cpu_start field to become non-zero After we set cpu_start,
105          * the processor will continue on to secondary_start
106          */
107         paca[nr].cpu_start = 1;
108         smp_mb();
109
110         return 0;
111 }
112 #endif
113
114 static irqreturn_t call_function_action(int irq, void *data)
115 {
116         generic_smp_call_function_interrupt();
117         return IRQ_HANDLED;
118 }
119
120 static irqreturn_t reschedule_action(int irq, void *data)
121 {
122         scheduler_ipi();
123         return IRQ_HANDLED;
124 }
125
126 static irqreturn_t call_function_single_action(int irq, void *data)
127 {
128         generic_smp_call_function_single_interrupt();
129         return IRQ_HANDLED;
130 }
131
132 static irqreturn_t debug_ipi_action(int irq, void *data)
133 {
134         if (crash_ipi_function_ptr) {
135                 crash_ipi_function_ptr(get_irq_regs());
136                 return IRQ_HANDLED;
137         }
138
139 #ifdef CONFIG_DEBUGGER
140         debugger_ipi(get_irq_regs());
141 #endif /* CONFIG_DEBUGGER */
142
143         return IRQ_HANDLED;
144 }
145
146 static irq_handler_t smp_ipi_action[] = {
147         [PPC_MSG_CALL_FUNCTION] =  call_function_action,
148         [PPC_MSG_RESCHEDULE] = reschedule_action,
149         [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action,
150         [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
151 };
152
153 const char *smp_ipi_name[] = {
154         [PPC_MSG_CALL_FUNCTION] =  "ipi call function",
155         [PPC_MSG_RESCHEDULE] = "ipi reschedule",
156         [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single",
157         [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
158 };
159
160 /* optional function to request ipi, for controllers with >= 4 ipis */
161 int smp_request_message_ipi(int virq, int msg)
162 {
163         int err;
164
165         if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
166                 return -EINVAL;
167         }
168 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC)
169         if (msg == PPC_MSG_DEBUGGER_BREAK) {
170                 return 1;
171         }
172 #endif
173         err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU,
174                           smp_ipi_name[msg], 0);
175         WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
176                 virq, smp_ipi_name[msg], err);
177
178         return err;
179 }
180
181 #ifdef CONFIG_PPC_SMP_MUXED_IPI
182 struct cpu_messages {
183         int messages;                   /* current messages */
184         unsigned long data;             /* data for cause ipi */
185 };
186 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
187
188 void smp_muxed_ipi_set_data(int cpu, unsigned long data)
189 {
190         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
191
192         info->data = data;
193 }
194
195 void smp_muxed_ipi_message_pass(int cpu, int msg)
196 {
197         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
198         char *message = (char *)&info->messages;
199
200         message[msg] = 1;
201         mb();
202         smp_ops->cause_ipi(cpu, info->data);
203 }
204
205 irqreturn_t smp_ipi_demux(void)
206 {
207         struct cpu_messages *info = &__get_cpu_var(ipi_message);
208         unsigned int all;
209
210         mb();   /* order any irq clear */
211
212         do {
213                 all = xchg_local(&info->messages, 0);
214
215 #ifdef __BIG_ENDIAN
216                 if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNCTION)))
217                         generic_smp_call_function_interrupt();
218                 if (all & (1 << (24 - 8 * PPC_MSG_RESCHEDULE)))
219                         scheduler_ipi();
220                 if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNC_SINGLE)))
221                         generic_smp_call_function_single_interrupt();
222                 if (all & (1 << (24 - 8 * PPC_MSG_DEBUGGER_BREAK)))
223                         debug_ipi_action(0, NULL);
224 #else
225 #error Unsupported ENDIAN
226 #endif
227         } while (info->messages);
228
229         return IRQ_HANDLED;
230 }
231 #endif /* CONFIG_PPC_SMP_MUXED_IPI */
232
233 static inline void do_message_pass(int cpu, int msg)
234 {
235         if (smp_ops->message_pass)
236                 smp_ops->message_pass(cpu, msg);
237 #ifdef CONFIG_PPC_SMP_MUXED_IPI
238         else
239                 smp_muxed_ipi_message_pass(cpu, msg);
240 #endif
241 }
242
243 void smp_send_reschedule(int cpu)
244 {
245         if (likely(smp_ops))
246                 do_message_pass(cpu, PPC_MSG_RESCHEDULE);
247 }
248 EXPORT_SYMBOL_GPL(smp_send_reschedule);
249
250 void arch_send_call_function_single_ipi(int cpu)
251 {
252         do_message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
253 }
254
255 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
256 {
257         unsigned int cpu;
258
259         for_each_cpu(cpu, mask)
260                 do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
261 }
262
263 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
264 void smp_send_debugger_break(void)
265 {
266         int cpu;
267         int me = raw_smp_processor_id();
268
269         if (unlikely(!smp_ops))
270                 return;
271
272         for_each_online_cpu(cpu)
273                 if (cpu != me)
274                         do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
275 }
276 #endif
277
278 #ifdef CONFIG_KEXEC
279 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
280 {
281         crash_ipi_function_ptr = crash_ipi_callback;
282         if (crash_ipi_callback) {
283                 mb();
284                 smp_send_debugger_break();
285         }
286 }
287 #endif
288
289 static void stop_this_cpu(void *dummy)
290 {
291         /* Remove this CPU */
292         set_cpu_online(smp_processor_id(), false);
293
294         local_irq_disable();
295         while (1)
296                 ;
297 }
298
299 void smp_send_stop(void)
300 {
301         smp_call_function(stop_this_cpu, NULL, 0);
302 }
303
304 struct thread_info *current_set[NR_CPUS];
305
306 static void __devinit smp_store_cpu_info(int id)
307 {
308         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
309 #ifdef CONFIG_PPC_FSL_BOOK3E
310         per_cpu(next_tlbcam_idx, id)
311                 = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
312 #endif
313 }
314
315 void __init smp_prepare_cpus(unsigned int max_cpus)
316 {
317         unsigned int cpu;
318
319         DBG("smp_prepare_cpus\n");
320
321         /* 
322          * setup_cpu may need to be called on the boot cpu. We havent
323          * spun any cpus up but lets be paranoid.
324          */
325         BUG_ON(boot_cpuid != smp_processor_id());
326
327         /* Fixup boot cpu */
328         smp_store_cpu_info(boot_cpuid);
329         cpu_callin_map[boot_cpuid] = 1;
330
331         for_each_possible_cpu(cpu) {
332                 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
333                                         GFP_KERNEL, cpu_to_node(cpu));
334                 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
335                                         GFP_KERNEL, cpu_to_node(cpu));
336         }
337
338         cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
339         cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
340
341         if (smp_ops)
342                 if (smp_ops->probe)
343                         max_cpus = smp_ops->probe();
344                 else
345                         max_cpus = NR_CPUS;
346         else
347                 max_cpus = 1;
348 }
349
350 void __devinit smp_prepare_boot_cpu(void)
351 {
352         BUG_ON(smp_processor_id() != boot_cpuid);
353 #ifdef CONFIG_PPC64
354         paca[boot_cpuid].__current = current;
355 #endif
356         current_set[boot_cpuid] = task_thread_info(current);
357 }
358
359 #ifdef CONFIG_HOTPLUG_CPU
360 /* State of each CPU during hotplug phases */
361 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
362
363 int generic_cpu_disable(void)
364 {
365         unsigned int cpu = smp_processor_id();
366
367         if (cpu == boot_cpuid)
368                 return -EBUSY;
369
370         set_cpu_online(cpu, false);
371 #ifdef CONFIG_PPC64
372         vdso_data->processorCount--;
373 #endif
374         migrate_irqs();
375         return 0;
376 }
377
378 void generic_cpu_die(unsigned int cpu)
379 {
380         int i;
381
382         for (i = 0; i < 100; i++) {
383                 smp_rmb();
384                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
385                         return;
386                 msleep(100);
387         }
388         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
389 }
390
391 void generic_mach_cpu_die(void)
392 {
393         unsigned int cpu;
394
395         local_irq_disable();
396         idle_task_exit();
397         cpu = smp_processor_id();
398         printk(KERN_DEBUG "CPU%d offline\n", cpu);
399         __get_cpu_var(cpu_state) = CPU_DEAD;
400         smp_wmb();
401         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
402                 cpu_relax();
403 }
404
405 void generic_set_cpu_dead(unsigned int cpu)
406 {
407         per_cpu(cpu_state, cpu) = CPU_DEAD;
408 }
409 #endif
410
411 struct create_idle {
412         struct work_struct work;
413         struct task_struct *idle;
414         struct completion done;
415         int cpu;
416 };
417
418 static void __cpuinit do_fork_idle(struct work_struct *work)
419 {
420         struct create_idle *c_idle =
421                 container_of(work, struct create_idle, work);
422
423         c_idle->idle = fork_idle(c_idle->cpu);
424         complete(&c_idle->done);
425 }
426
427 static int __cpuinit create_idle(unsigned int cpu)
428 {
429         struct thread_info *ti;
430         struct create_idle c_idle = {
431                 .cpu    = cpu,
432                 .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
433         };
434         INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
435
436         c_idle.idle = get_idle_for_cpu(cpu);
437
438         /* We can't use kernel_thread since we must avoid to
439          * reschedule the child. We use a workqueue because
440          * we want to fork from a kernel thread, not whatever
441          * userspace process happens to be trying to online us.
442          */
443         if (!c_idle.idle) {
444                 schedule_work(&c_idle.work);
445                 wait_for_completion(&c_idle.done);
446         } else
447                 init_idle(c_idle.idle, cpu);
448         if (IS_ERR(c_idle.idle)) {              
449                 pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
450                 return PTR_ERR(c_idle.idle);
451         }
452         ti = task_thread_info(c_idle.idle);
453
454 #ifdef CONFIG_PPC64
455         paca[cpu].__current = c_idle.idle;
456         paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
457 #endif
458         ti->cpu = cpu;
459         current_set[cpu] = ti;
460
461         return 0;
462 }
463
464 int __cpuinit __cpu_up(unsigned int cpu)
465 {
466         int rc, c;
467
468         if (smp_ops == NULL ||
469             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
470                 return -EINVAL;
471
472         /* Make sure we have an idle thread */
473         rc = create_idle(cpu);
474         if (rc)
475                 return rc;
476
477         secondary_ti = current_set[cpu];
478
479         /* Make sure callin-map entry is 0 (can be leftover a CPU
480          * hotplug
481          */
482         cpu_callin_map[cpu] = 0;
483
484         /* The information for processor bringup must
485          * be written out to main store before we release
486          * the processor.
487          */
488         smp_mb();
489
490         /* wake up cpus */
491         DBG("smp: kicking cpu %d\n", cpu);
492         rc = smp_ops->kick_cpu(cpu);
493         if (rc) {
494                 pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
495                 return rc;
496         }
497
498         /*
499          * wait to see if the cpu made a callin (is actually up).
500          * use this value that I found through experimentation.
501          * -- Cort
502          */
503         if (system_state < SYSTEM_RUNNING)
504                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
505                         udelay(100);
506 #ifdef CONFIG_HOTPLUG_CPU
507         else
508                 /*
509                  * CPUs can take much longer to come up in the
510                  * hotplug case.  Wait five seconds.
511                  */
512                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
513                         msleep(1);
514 #endif
515
516         if (!cpu_callin_map[cpu]) {
517                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
518                 return -ENOENT;
519         }
520
521         DBG("Processor %u found.\n", cpu);
522
523         if (smp_ops->give_timebase)
524                 smp_ops->give_timebase();
525
526         /* Wait until cpu puts itself in the online map */
527         while (!cpu_online(cpu))
528                 cpu_relax();
529
530         return 0;
531 }
532
533 /* Return the value of the reg property corresponding to the given
534  * logical cpu.
535  */
536 int cpu_to_core_id(int cpu)
537 {
538         struct device_node *np;
539         const int *reg;
540         int id = -1;
541
542         np = of_get_cpu_node(cpu, NULL);
543         if (!np)
544                 goto out;
545
546         reg = of_get_property(np, "reg", NULL);
547         if (!reg)
548                 goto out;
549
550         id = *reg;
551 out:
552         of_node_put(np);
553         return id;
554 }
555
556 /* Helper routines for cpu to core mapping */
557 int cpu_core_index_of_thread(int cpu)
558 {
559         return cpu >> threads_shift;
560 }
561 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
562
563 int cpu_first_thread_of_core(int core)
564 {
565         return core << threads_shift;
566 }
567 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
568
569 /* Must be called when no change can occur to cpu_present_mask,
570  * i.e. during cpu online or offline.
571  */
572 static struct device_node *cpu_to_l2cache(int cpu)
573 {
574         struct device_node *np;
575         struct device_node *cache;
576
577         if (!cpu_present(cpu))
578                 return NULL;
579
580         np = of_get_cpu_node(cpu, NULL);
581         if (np == NULL)
582                 return NULL;
583
584         cache = of_find_next_cache_node(np);
585
586         of_node_put(np);
587
588         return cache;
589 }
590
591 /* Activate a secondary processor. */
592 void __devinit start_secondary(void *unused)
593 {
594         unsigned int cpu = smp_processor_id();
595         struct device_node *l2_cache;
596         int i, base;
597
598         atomic_inc(&init_mm.mm_count);
599         current->active_mm = &init_mm;
600
601         smp_store_cpu_info(cpu);
602         set_dec(tb_ticks_per_jiffy);
603         preempt_disable();
604         cpu_callin_map[cpu] = 1;
605
606         if (smp_ops->setup_cpu)
607                 smp_ops->setup_cpu(cpu);
608         if (smp_ops->take_timebase)
609                 smp_ops->take_timebase();
610
611         secondary_cpu_time_init();
612
613 #ifdef CONFIG_PPC64
614         if (system_state == SYSTEM_RUNNING)
615                 vdso_data->processorCount++;
616 #endif
617         ipi_call_lock();
618         notify_cpu_starting(cpu);
619         set_cpu_online(cpu, true);
620         /* Update sibling maps */
621         base = cpu_first_thread_sibling(cpu);
622         for (i = 0; i < threads_per_core; i++) {
623                 if (cpu_is_offline(base + i))
624                         continue;
625                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
626                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
627
628                 /* cpu_core_map should be a superset of
629                  * cpu_sibling_map even if we don't have cache
630                  * information, so update the former here, too.
631                  */
632                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
633                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
634         }
635         l2_cache = cpu_to_l2cache(cpu);
636         for_each_online_cpu(i) {
637                 struct device_node *np = cpu_to_l2cache(i);
638                 if (!np)
639                         continue;
640                 if (np == l2_cache) {
641                         cpumask_set_cpu(cpu, cpu_core_mask(i));
642                         cpumask_set_cpu(i, cpu_core_mask(cpu));
643                 }
644                 of_node_put(np);
645         }
646         of_node_put(l2_cache);
647         ipi_call_unlock();
648
649         local_irq_enable();
650
651         cpu_idle();
652
653         BUG();
654 }
655
656 int setup_profiling_timer(unsigned int multiplier)
657 {
658         return 0;
659 }
660
661 void __init smp_cpus_done(unsigned int max_cpus)
662 {
663         cpumask_var_t old_mask;
664
665         /* We want the setup_cpu() here to be called from CPU 0, but our
666          * init thread may have been "borrowed" by another CPU in the meantime
667          * se we pin us down to CPU 0 for a short while
668          */
669         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
670         cpumask_copy(old_mask, tsk_cpus_allowed(current));
671         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
672         
673         if (smp_ops && smp_ops->setup_cpu)
674                 smp_ops->setup_cpu(boot_cpuid);
675
676         set_cpus_allowed_ptr(current, old_mask);
677
678         free_cpumask_var(old_mask);
679
680         if (smp_ops && smp_ops->bringup_done)
681                 smp_ops->bringup_done();
682
683         dump_numa_cpu_topology();
684
685 }
686
687 int arch_sd_sibling_asym_packing(void)
688 {
689         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
690                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
691                 return SD_ASYM_PACKING;
692         }
693         return 0;
694 }
695
696 #ifdef CONFIG_HOTPLUG_CPU
697 int __cpu_disable(void)
698 {
699         struct device_node *l2_cache;
700         int cpu = smp_processor_id();
701         int base, i;
702         int err;
703
704         if (!smp_ops->cpu_disable)
705                 return -ENOSYS;
706
707         err = smp_ops->cpu_disable();
708         if (err)
709                 return err;
710
711         /* Update sibling maps */
712         base = cpu_first_thread_sibling(cpu);
713         for (i = 0; i < threads_per_core; i++) {
714                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
715                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
716                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
717                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
718         }
719
720         l2_cache = cpu_to_l2cache(cpu);
721         for_each_present_cpu(i) {
722                 struct device_node *np = cpu_to_l2cache(i);
723                 if (!np)
724                         continue;
725                 if (np == l2_cache) {
726                         cpumask_clear_cpu(cpu, cpu_core_mask(i));
727                         cpumask_clear_cpu(i, cpu_core_mask(cpu));
728                 }
729                 of_node_put(np);
730         }
731         of_node_put(l2_cache);
732
733
734         return 0;
735 }
736
737 void __cpu_die(unsigned int cpu)
738 {
739         if (smp_ops->cpu_die)
740                 smp_ops->cpu_die(cpu);
741 }
742
743 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
744
745 void cpu_hotplug_driver_lock()
746 {
747         mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
748 }
749
750 void cpu_hotplug_driver_unlock()
751 {
752         mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
753 }
754
755 void cpu_die(void)
756 {
757         if (ppc_md.cpu_die)
758                 ppc_md.cpu_die();
759
760         /* If we return, we re-enter start_secondary */
761         start_secondary_resume();
762 }
763
764 #endif