xref: /linux/arch/s390/kernel/smp.c (revision 13abf8130139c2ccd4962a7e5a8902be5e6cb5a7)
1 /*
2  *  arch/s390/kernel/smp.c
3  *
4  *  S390 version
5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
8  *               Heiko Carstens (heiko.carstens@de.ibm.com)
9  *
10  *  based on other smp stuff by
11  *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
12  *    (c) 1998 Ingo Molnar
13  *
14  * We work with logical cpu numbering everywhere we can. The only
15  * functions using the real cpu address (got from STAP) are the sigp
16  * functions. For all other functions we use the identity mapping.
17  * That means that cpu_number_map[i] == i for every cpu. cpu_number_map is
18  * used e.g. to find the idle task belonging to a logical cpu. Every array
19  * in the kernel is sorted by the logical cpu number and not by the physical
20  * one which is causing all the confusion with __cpu_logical_map and
21  * cpu_number_map in other architectures.
22  */
23 
24 #include <linux/module.h>
25 #include <linux/init.h>
26 
27 #include <linux/mm.h>
28 #include <linux/spinlock.h>
29 #include <linux/kernel_stat.h>
30 #include <linux/smp_lock.h>
31 
32 #include <linux/delay.h>
33 #include <linux/cache.h>
34 #include <linux/interrupt.h>
35 #include <linux/cpu.h>
36 
37 #include <asm/sigp.h>
38 #include <asm/pgalloc.h>
39 #include <asm/irq.h>
40 #include <asm/s390_ext.h>
41 #include <asm/cpcmd.h>
42 #include <asm/tlbflush.h>
43 
44 /* prototypes */
45 
46 extern volatile int __cpu_logical_map[];
47 
48 /*
49  * An array with a pointer the lowcore of every CPU.
50  */
51 
52 struct _lowcore *lowcore_ptr[NR_CPUS];
53 
54 cpumask_t cpu_online_map;
55 cpumask_t cpu_possible_map;
56 
57 static struct task_struct *current_set[NR_CPUS];
58 
59 EXPORT_SYMBOL(cpu_online_map);
60 
61 /*
62  * Reboot, halt and power_off routines for SMP.
63  */
64 extern char vmhalt_cmd[];
65 extern char vmpoff_cmd[];
66 
67 extern void reipl(unsigned long devno);
68 
69 static void smp_ext_bitcall(int, ec_bit_sig);
70 static void smp_ext_bitcall_others(ec_bit_sig);
71 
72 /*
73  * Structure and data for smp_call_function(). This is designed to minimise
74  * static memory requirements. It also looks cleaner.
75  */
76 static DEFINE_SPINLOCK(call_lock);
77 
78 struct call_data_struct {
79 	void (*func) (void *info);
80 	void *info;
81 	atomic_t started;
82 	atomic_t finished;
83 	int wait;
84 };
85 
86 static struct call_data_struct * call_data;
87 
88 /*
89  * 'Call function' interrupt callback
90  */
91 static void do_call_function(void)
92 {
93 	void (*func) (void *info) = call_data->func;
94 	void *info = call_data->info;
95 	int wait = call_data->wait;
96 
97 	atomic_inc(&call_data->started);
98 	(*func)(info);
99 	if (wait)
100 		atomic_inc(&call_data->finished);
101 }
102 
103 /*
104  * this function sends a 'generic call function' IPI to all other CPUs
105  * in the system.
106  */
107 
108 int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
109 			int wait)
110 /*
111  * [SUMMARY] Run a function on all other CPUs.
112  * <func> The function to run. This must be fast and non-blocking.
113  * <info> An arbitrary pointer to pass to the function.
114  * <nonatomic> currently unused.
115  * <wait> If true, wait (atomically) until function has completed on other CPUs.
116  * [RETURNS] 0 on success, else a negative status code. Does not return until
117  * remote CPUs are nearly ready to execute <<func>> or are or have executed.
118  *
119  * You must not call this function with disabled interrupts or from a
120  * hardware interrupt handler or from a bottom half handler.
121  */
122 {
123 	struct call_data_struct data;
124 	int cpus = num_online_cpus()-1;
125 
126 	if (cpus <= 0)
127 		return 0;
128 
129 	/* Can deadlock when called with interrupts disabled */
130 	WARN_ON(irqs_disabled());
131 
132 	data.func = func;
133 	data.info = info;
134 	atomic_set(&data.started, 0);
135 	data.wait = wait;
136 	if (wait)
137 		atomic_set(&data.finished, 0);
138 
139 	spin_lock(&call_lock);
140 	call_data = &data;
141 	/* Send a message to all other CPUs and wait for them to respond */
142         smp_ext_bitcall_others(ec_call_function);
143 
144 	/* Wait for response */
145 	while (atomic_read(&data.started) != cpus)
146 		cpu_relax();
147 
148 	if (wait)
149 		while (atomic_read(&data.finished) != cpus)
150 			cpu_relax();
151 	spin_unlock(&call_lock);
152 
153 	return 0;
154 }
155 
156 /*
157  * Call a function on one CPU
158  * cpu : the CPU the function should be executed on
159  *
160  * You must not call this function with disabled interrupts or from a
161  * hardware interrupt handler. You may call it from a bottom half.
162  *
163  * It is guaranteed that the called function runs on the specified CPU,
164  * preemption is disabled.
165  */
166 int smp_call_function_on(void (*func) (void *info), void *info,
167 			 int nonatomic, int wait, int cpu)
168 {
169 	struct call_data_struct data;
170 	int curr_cpu;
171 
172 	if (!cpu_online(cpu))
173 		return -EINVAL;
174 
175 	/* disable preemption for local function call */
176 	curr_cpu = get_cpu();
177 
178 	if (curr_cpu == cpu) {
179 		/* direct call to function */
180 		func(info);
181 		put_cpu();
182 		return 0;
183 	}
184 
185 	data.func = func;
186 	data.info = info;
187 	atomic_set(&data.started, 0);
188 	data.wait = wait;
189 	if (wait)
190 		atomic_set(&data.finished, 0);
191 
192 	spin_lock_bh(&call_lock);
193 	call_data = &data;
194 	smp_ext_bitcall(cpu, ec_call_function);
195 
196 	/* Wait for response */
197 	while (atomic_read(&data.started) != 1)
198 		cpu_relax();
199 
200 	if (wait)
201 		while (atomic_read(&data.finished) != 1)
202 			cpu_relax();
203 
204 	spin_unlock_bh(&call_lock);
205 	put_cpu();
206 	return 0;
207 }
208 EXPORT_SYMBOL(smp_call_function_on);
209 
210 static inline void do_send_stop(void)
211 {
212         int cpu, rc;
213 
214         /* stop all processors */
215 	for_each_online_cpu(cpu) {
216 		if (cpu == smp_processor_id())
217 			continue;
218 		do {
219 			rc = signal_processor(cpu, sigp_stop);
220 		} while (rc == sigp_busy);
221 	}
222 }
223 
224 static inline void do_store_status(void)
225 {
226         int cpu, rc;
227 
228         /* store status of all processors in their lowcores (real 0) */
229 	for_each_online_cpu(cpu) {
230 		if (cpu == smp_processor_id())
231 			continue;
232 		do {
233 			rc = signal_processor_p(
234 				(__u32)(unsigned long) lowcore_ptr[cpu], cpu,
235 				sigp_store_status_at_address);
236 		} while(rc == sigp_busy);
237         }
238 }
239 
240 /*
241  * this function sends a 'stop' sigp to all other CPUs in the system.
242  * it goes straight through.
243  */
244 void smp_send_stop(void)
245 {
246         /* write magic number to zero page (absolute 0) */
247 	lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;
248 
249 	/* stop other processors. */
250 	do_send_stop();
251 
252 	/* store status of other processors. */
253 	do_store_status();
254 }
255 
256 /*
257  * Reboot, halt and power_off routines for SMP.
258  */
259 
260 static void do_machine_restart(void * __unused)
261 {
262 	int cpu;
263 	static atomic_t cpuid = ATOMIC_INIT(-1);
264 
265 	if (atomic_compare_and_swap(-1, smp_processor_id(), &cpuid))
266 		signal_processor(smp_processor_id(), sigp_stop);
267 
268 	/* Wait for all other cpus to enter stopped state */
269 	for_each_online_cpu(cpu) {
270 		if (cpu == smp_processor_id())
271 			continue;
272 		while(!smp_cpu_not_running(cpu))
273 			cpu_relax();
274 	}
275 
276 	/* Store status of other cpus. */
277 	do_store_status();
278 
279 	/*
280 	 * Finally call reipl. Because we waited for all other
281 	 * cpus to enter this function we know that they do
282 	 * not hold any s390irq-locks (the cpus have been
283 	 * interrupted by an external interrupt and s390irq
284 	 * locks are always held disabled).
285 	 */
286 	if (MACHINE_IS_VM)
287 		cpcmd ("IPL", NULL, 0, NULL);
288 	else
289 		reipl (0x10000 | S390_lowcore.ipl_device);
290 }
291 
292 void machine_restart_smp(char * __unused)
293 {
294         on_each_cpu(do_machine_restart, NULL, 0, 0);
295 }
296 
297 static void do_wait_for_stop(void)
298 {
299 	unsigned long cr[16];
300 
301 	__ctl_store(cr, 0, 15);
302 	cr[0] &= ~0xffff;
303 	cr[6] = 0;
304 	__ctl_load(cr, 0, 15);
305 	for (;;)
306 		enabled_wait();
307 }
308 
309 static void do_machine_halt(void * __unused)
310 {
311 	static atomic_t cpuid = ATOMIC_INIT(-1);
312 
313 	if (atomic_compare_and_swap(-1, smp_processor_id(), &cpuid) == 0) {
314 		smp_send_stop();
315 		if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)
316 			cpcmd(vmhalt_cmd, NULL, 0, NULL);
317 		signal_processor(smp_processor_id(),
318 				 sigp_stop_and_store_status);
319 	}
320 	do_wait_for_stop();
321 }
322 
323 void machine_halt_smp(void)
324 {
325         on_each_cpu(do_machine_halt, NULL, 0, 0);
326 }
327 
328 static void do_machine_power_off(void * __unused)
329 {
330 	static atomic_t cpuid = ATOMIC_INIT(-1);
331 
332 	if (atomic_compare_and_swap(-1, smp_processor_id(), &cpuid) == 0) {
333 		smp_send_stop();
334 		if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)
335 			cpcmd(vmpoff_cmd, NULL, 0, NULL);
336 		signal_processor(smp_processor_id(),
337 				 sigp_stop_and_store_status);
338 	}
339 	do_wait_for_stop();
340 }
341 
342 void machine_power_off_smp(void)
343 {
344         on_each_cpu(do_machine_power_off, NULL, 0, 0);
345 }
346 
347 /*
348  * This is the main routine where commands issued by other
349  * cpus are handled.
350  */
351 
352 void do_ext_call_interrupt(struct pt_regs *regs, __u16 code)
353 {
354         unsigned long bits;
355 
356         /*
357          * handle bit signal external calls
358          *
359          * For the ec_schedule signal we have to do nothing. All the work
360          * is done automatically when we return from the interrupt.
361          */
362 	bits = xchg(&S390_lowcore.ext_call_fast, 0);
363 
364 	if (test_bit(ec_call_function, &bits))
365 		do_call_function();
366 }
367 
368 /*
369  * Send an external call sigp to another cpu and return without waiting
370  * for its completion.
371  */
372 static void smp_ext_bitcall(int cpu, ec_bit_sig sig)
373 {
374         /*
375          * Set signaling bit in lowcore of target cpu and kick it
376          */
377 	set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
378 	while(signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
379 		udelay(10);
380 }
381 
382 /*
383  * Send an external call sigp to every other cpu in the system and
384  * return without waiting for its completion.
385  */
386 static void smp_ext_bitcall_others(ec_bit_sig sig)
387 {
388         int cpu;
389 
390 	for_each_online_cpu(cpu) {
391 		if (cpu == smp_processor_id())
392                         continue;
393                 /*
394                  * Set signaling bit in lowcore of target cpu and kick it
395                  */
396 		set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
397 		while (signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
398 			udelay(10);
399         }
400 }
401 
402 #ifndef CONFIG_ARCH_S390X
403 /*
404  * this function sends a 'purge tlb' signal to another CPU.
405  */
406 void smp_ptlb_callback(void *info)
407 {
408 	local_flush_tlb();
409 }
410 
411 void smp_ptlb_all(void)
412 {
413         on_each_cpu(smp_ptlb_callback, NULL, 0, 1);
414 }
415 EXPORT_SYMBOL(smp_ptlb_all);
416 #endif /* ! CONFIG_ARCH_S390X */
417 
418 /*
419  * this function sends a 'reschedule' IPI to another CPU.
420  * it goes straight through and wastes no time serializing
421  * anything. Worst case is that we lose a reschedule ...
422  */
423 void smp_send_reschedule(int cpu)
424 {
425         smp_ext_bitcall(cpu, ec_schedule);
426 }
427 
428 /*
429  * parameter area for the set/clear control bit callbacks
430  */
431 typedef struct
432 {
433 	__u16 start_ctl;
434 	__u16 end_ctl;
435 	unsigned long orvals[16];
436 	unsigned long andvals[16];
437 } ec_creg_mask_parms;
438 
439 /*
440  * callback for setting/clearing control bits
441  */
442 void smp_ctl_bit_callback(void *info) {
443 	ec_creg_mask_parms *pp;
444 	unsigned long cregs[16];
445 	int i;
446 
447 	pp = (ec_creg_mask_parms *) info;
448 	__ctl_store(cregs[pp->start_ctl], pp->start_ctl, pp->end_ctl);
449 	for (i = pp->start_ctl; i <= pp->end_ctl; i++)
450 		cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
451 	__ctl_load(cregs[pp->start_ctl], pp->start_ctl, pp->end_ctl);
452 }
453 
454 /*
455  * Set a bit in a control register of all cpus
456  */
457 void smp_ctl_set_bit(int cr, int bit) {
458         ec_creg_mask_parms parms;
459 
460 	parms.start_ctl = cr;
461 	parms.end_ctl = cr;
462 	parms.orvals[cr] = 1 << bit;
463 	parms.andvals[cr] = -1L;
464 	preempt_disable();
465 	smp_call_function(smp_ctl_bit_callback, &parms, 0, 1);
466         __ctl_set_bit(cr, bit);
467 	preempt_enable();
468 }
469 
470 /*
471  * Clear a bit in a control register of all cpus
472  */
473 void smp_ctl_clear_bit(int cr, int bit) {
474         ec_creg_mask_parms parms;
475 
476 	parms.start_ctl = cr;
477 	parms.end_ctl = cr;
478 	parms.orvals[cr] = 0;
479 	parms.andvals[cr] = ~(1L << bit);
480 	preempt_disable();
481 	smp_call_function(smp_ctl_bit_callback, &parms, 0, 1);
482         __ctl_clear_bit(cr, bit);
483 	preempt_enable();
484 }
485 
486 /*
487  * Lets check how many CPUs we have.
488  */
489 
490 void
491 __init smp_check_cpus(unsigned int max_cpus)
492 {
493 	int cpu, num_cpus;
494 	__u16 boot_cpu_addr;
495 
496 	/*
497 	 * cpu 0 is the boot cpu. See smp_prepare_boot_cpu.
498 	 */
499 
500 	boot_cpu_addr = S390_lowcore.cpu_data.cpu_addr;
501 	current_thread_info()->cpu = 0;
502 	num_cpus = 1;
503 	for (cpu = 0; cpu <= 65535 && num_cpus < max_cpus; cpu++) {
504 		if ((__u16) cpu == boot_cpu_addr)
505 			continue;
506 		__cpu_logical_map[num_cpus] = (__u16) cpu;
507 		if (signal_processor(num_cpus, sigp_sense) ==
508 		    sigp_not_operational)
509 			continue;
510 		cpu_set(num_cpus, cpu_present_map);
511 		num_cpus++;
512 	}
513 
514 	for (cpu = 1; cpu < max_cpus; cpu++)
515 		cpu_set(cpu, cpu_possible_map);
516 
517 	printk("Detected %d CPU's\n",(int) num_cpus);
518 	printk("Boot cpu address %2X\n", boot_cpu_addr);
519 }
520 
521 /*
522  *      Activate a secondary processor.
523  */
524 extern void init_cpu_timer(void);
525 extern void init_cpu_vtimer(void);
526 extern int pfault_init(void);
527 extern void pfault_fini(void);
528 
529 int __devinit start_secondary(void *cpuvoid)
530 {
531         /* Setup the cpu */
532         cpu_init();
533         /* init per CPU timer */
534         init_cpu_timer();
535 #ifdef CONFIG_VIRT_TIMER
536         init_cpu_vtimer();
537 #endif
538 #ifdef CONFIG_PFAULT
539 	/* Enable pfault pseudo page faults on this cpu. */
540 	if (MACHINE_IS_VM)
541 		pfault_init();
542 #endif
543 	/* Mark this cpu as online */
544 	cpu_set(smp_processor_id(), cpu_online_map);
545 	/* Switch on interrupts */
546 	local_irq_enable();
547         /* Print info about this processor */
548         print_cpu_info(&S390_lowcore.cpu_data);
549         /* cpu_idle will call schedule for us */
550         cpu_idle();
551         return 0;
552 }
553 
554 static void __init smp_create_idle(unsigned int cpu)
555 {
556 	struct task_struct *p;
557 
558 	/*
559 	 *  don't care about the psw and regs settings since we'll never
560 	 *  reschedule the forked task.
561 	 */
562 	p = fork_idle(cpu);
563 	if (IS_ERR(p))
564 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
565 	current_set[cpu] = p;
566 }
567 
568 /* Reserving and releasing of CPUs */
569 
570 static DEFINE_SPINLOCK(smp_reserve_lock);
571 static int smp_cpu_reserved[NR_CPUS];
572 
573 int
574 smp_get_cpu(cpumask_t cpu_mask)
575 {
576 	unsigned long flags;
577 	int cpu;
578 
579 	spin_lock_irqsave(&smp_reserve_lock, flags);
580 	/* Try to find an already reserved cpu. */
581 	for_each_cpu_mask(cpu, cpu_mask) {
582 		if (smp_cpu_reserved[cpu] != 0) {
583 			smp_cpu_reserved[cpu]++;
584 			/* Found one. */
585 			goto out;
586 		}
587 	}
588 	/* Reserve a new cpu from cpu_mask. */
589 	for_each_cpu_mask(cpu, cpu_mask) {
590 		if (cpu_online(cpu)) {
591 			smp_cpu_reserved[cpu]++;
592 			goto out;
593 		}
594 	}
595 	cpu = -ENODEV;
596 out:
597 	spin_unlock_irqrestore(&smp_reserve_lock, flags);
598 	return cpu;
599 }
600 
601 void
602 smp_put_cpu(int cpu)
603 {
604 	unsigned long flags;
605 
606 	spin_lock_irqsave(&smp_reserve_lock, flags);
607 	smp_cpu_reserved[cpu]--;
608 	spin_unlock_irqrestore(&smp_reserve_lock, flags);
609 }
610 
611 static inline int
612 cpu_stopped(int cpu)
613 {
614 	__u32 status;
615 
616 	/* Check for stopped state */
617 	if (signal_processor_ps(&status, 0, cpu, sigp_sense) == sigp_status_stored) {
618 		if (status & 0x40)
619 			return 1;
620 	}
621 	return 0;
622 }
623 
624 /* Upping and downing of CPUs */
625 
626 int
627 __cpu_up(unsigned int cpu)
628 {
629 	struct task_struct *idle;
630         struct _lowcore    *cpu_lowcore;
631 	struct stack_frame *sf;
632         sigp_ccode          ccode;
633 	int                 curr_cpu;
634 
635 	for (curr_cpu = 0; curr_cpu <= 65535; curr_cpu++) {
636 		__cpu_logical_map[cpu] = (__u16) curr_cpu;
637 		if (cpu_stopped(cpu))
638 			break;
639 	}
640 
641 	if (!cpu_stopped(cpu))
642 		return -ENODEV;
643 
644 	ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
645 				   cpu, sigp_set_prefix);
646 	if (ccode){
647 		printk("sigp_set_prefix failed for cpu %d "
648 		       "with condition code %d\n",
649 		       (int) cpu, (int) ccode);
650 		return -EIO;
651 	}
652 
653 	idle = current_set[cpu];
654         cpu_lowcore = lowcore_ptr[cpu];
655 	cpu_lowcore->kernel_stack = (unsigned long)
656 		idle->thread_info + (THREAD_SIZE);
657 	sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
658 				     - sizeof(struct pt_regs)
659 				     - sizeof(struct stack_frame));
660 	memset(sf, 0, sizeof(struct stack_frame));
661 	sf->gprs[9] = (unsigned long) sf;
662 	cpu_lowcore->save_area[15] = (unsigned long) sf;
663 	__ctl_store(cpu_lowcore->cregs_save_area[0], 0, 15);
664 	__asm__ __volatile__("stam  0,15,0(%0)"
665 			     : : "a" (&cpu_lowcore->access_regs_save_area)
666 			     : "memory");
667 	cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
668         cpu_lowcore->current_task = (unsigned long) idle;
669         cpu_lowcore->cpu_data.cpu_nr = cpu;
670 	eieio();
671 	signal_processor(cpu,sigp_restart);
672 
673 	while (!cpu_online(cpu))
674 		cpu_relax();
675 	return 0;
676 }
677 
678 int
679 __cpu_disable(void)
680 {
681 	unsigned long flags;
682 	ec_creg_mask_parms cr_parms;
683 	int cpu = smp_processor_id();
684 
685 	spin_lock_irqsave(&smp_reserve_lock, flags);
686 	if (smp_cpu_reserved[cpu] != 0) {
687 		spin_unlock_irqrestore(&smp_reserve_lock, flags);
688 		return -EBUSY;
689 	}
690 	cpu_clear(cpu, cpu_online_map);
691 
692 #ifdef CONFIG_PFAULT
693 	/* Disable pfault pseudo page faults on this cpu. */
694 	if (MACHINE_IS_VM)
695 		pfault_fini();
696 #endif
697 
698 	/* disable all external interrupts */
699 
700 	cr_parms.start_ctl = 0;
701 	cr_parms.end_ctl = 0;
702 	cr_parms.orvals[0] = 0;
703 	cr_parms.andvals[0] = ~(1<<15 | 1<<14 | 1<<13 | 1<<12 |
704 				1<<11 | 1<<10 | 1<< 6 | 1<< 4);
705 	smp_ctl_bit_callback(&cr_parms);
706 
707 	/* disable all I/O interrupts */
708 
709 	cr_parms.start_ctl = 6;
710 	cr_parms.end_ctl = 6;
711 	cr_parms.orvals[6] = 0;
712 	cr_parms.andvals[6] = ~(1<<31 | 1<<30 | 1<<29 | 1<<28 |
713 				1<<27 | 1<<26 | 1<<25 | 1<<24);
714 	smp_ctl_bit_callback(&cr_parms);
715 
716 	/* disable most machine checks */
717 
718 	cr_parms.start_ctl = 14;
719 	cr_parms.end_ctl = 14;
720 	cr_parms.orvals[14] = 0;
721 	cr_parms.andvals[14] = ~(1<<28 | 1<<27 | 1<<26 | 1<<25 | 1<<24);
722 	smp_ctl_bit_callback(&cr_parms);
723 
724 	spin_unlock_irqrestore(&smp_reserve_lock, flags);
725 	return 0;
726 }
727 
728 void
729 __cpu_die(unsigned int cpu)
730 {
731 	/* Wait until target cpu is down */
732 	while (!smp_cpu_not_running(cpu))
733 		cpu_relax();
734 	printk("Processor %d spun down\n", cpu);
735 }
736 
737 void
738 cpu_die(void)
739 {
740 	idle_task_exit();
741 	signal_processor(smp_processor_id(), sigp_stop);
742 	BUG();
743 	for(;;);
744 }
745 
746 /*
747  *	Cycle through the processors and setup structures.
748  */
749 
750 void __init smp_prepare_cpus(unsigned int max_cpus)
751 {
752 	unsigned long stack;
753 	unsigned int cpu;
754         int i;
755 
756         /* request the 0x1201 emergency signal external interrupt */
757         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
758                 panic("Couldn't request external interrupt 0x1201");
759         smp_check_cpus(max_cpus);
760         memset(lowcore_ptr,0,sizeof(lowcore_ptr));
761         /*
762          *  Initialize prefix pages and stacks for all possible cpus
763          */
764 	print_cpu_info(&S390_lowcore.cpu_data);
765 
766         for(i = 0; i < NR_CPUS; i++) {
767 		if (!cpu_possible(i))
768 			continue;
769 		lowcore_ptr[i] = (struct _lowcore *)
770 			__get_free_pages(GFP_KERNEL|GFP_DMA,
771 					sizeof(void*) == 8 ? 1 : 0);
772 		stack = __get_free_pages(GFP_KERNEL,ASYNC_ORDER);
773 		if (lowcore_ptr[i] == NULL || stack == 0ULL)
774 			panic("smp_boot_cpus failed to allocate memory\n");
775 
776 		*(lowcore_ptr[i]) = S390_lowcore;
777 		lowcore_ptr[i]->async_stack = stack + (ASYNC_SIZE);
778 		stack = __get_free_pages(GFP_KERNEL,0);
779 		if (stack == 0ULL)
780 			panic("smp_boot_cpus failed to allocate memory\n");
781 		lowcore_ptr[i]->panic_stack = stack + (PAGE_SIZE);
782 #ifndef __s390x__
783 		if (MACHINE_HAS_IEEE) {
784 			lowcore_ptr[i]->extended_save_area_addr =
785 				(__u32) __get_free_pages(GFP_KERNEL,0);
786 			if (lowcore_ptr[i]->extended_save_area_addr == 0)
787 				panic("smp_boot_cpus failed to "
788 				      "allocate memory\n");
789 		}
790 #endif
791 	}
792 #ifndef __s390x__
793 	if (MACHINE_HAS_IEEE)
794 		ctl_set_bit(14, 29); /* enable extended save area */
795 #endif
796 	set_prefix((u32)(unsigned long) lowcore_ptr[smp_processor_id()]);
797 
798 	for_each_cpu(cpu)
799 		if (cpu != smp_processor_id())
800 			smp_create_idle(cpu);
801 }
802 
803 void __devinit smp_prepare_boot_cpu(void)
804 {
805 	BUG_ON(smp_processor_id() != 0);
806 
807 	cpu_set(0, cpu_online_map);
808 	cpu_set(0, cpu_present_map);
809 	cpu_set(0, cpu_possible_map);
810 	S390_lowcore.percpu_offset = __per_cpu_offset[0];
811 	current_set[0] = current;
812 }
813 
814 void smp_cpus_done(unsigned int max_cpus)
815 {
816 	cpu_present_map = cpu_possible_map;
817 }
818 
819 /*
820  * the frequency of the profiling timer can be changed
821  * by writing a multiplier value into /proc/profile.
822  *
823  * usually you want to run this on all CPUs ;)
824  */
825 int setup_profiling_timer(unsigned int multiplier)
826 {
827         return 0;
828 }
829 
830 static DEFINE_PER_CPU(struct cpu, cpu_devices);
831 
832 static int __init topology_init(void)
833 {
834 	int cpu;
835 	int ret;
836 
837 	for_each_cpu(cpu) {
838 		ret = register_cpu(&per_cpu(cpu_devices, cpu), cpu, NULL);
839 		if (ret)
840 			printk(KERN_WARNING "topology_init: register_cpu %d "
841 			       "failed (%d)\n", cpu, ret);
842 	}
843 	return 0;
844 }
845 
846 subsys_initcall(topology_init);
847 
848 EXPORT_SYMBOL(cpu_possible_map);
849 EXPORT_SYMBOL(lowcore_ptr);
850 EXPORT_SYMBOL(smp_ctl_set_bit);
851 EXPORT_SYMBOL(smp_ctl_clear_bit);
852 EXPORT_SYMBOL(smp_call_function);
853 EXPORT_SYMBOL(smp_get_cpu);
854 EXPORT_SYMBOL(smp_put_cpu);
855 
856