xref: /openbmc/linux/arch/s390/kernel/smp.c (revision c21b37f6)
1 /*
2  *  arch/s390/kernel/smp.c
3  *
4  *    Copyright IBM Corp. 1999,2007
5  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
6  *		 Martin Schwidefsky (schwidefsky@de.ibm.com)
7  *		 Heiko Carstens (heiko.carstens@de.ibm.com)
8  *
9  *  based on other smp stuff by
10  *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
11  *    (c) 1998 Ingo Molnar
12  *
13  * We work with logical cpu numbering everywhere we can. The only
14  * functions using the real cpu address (got from STAP) are the sigp
15  * functions. For all other functions we use the identity mapping.
16  * That means that cpu_number_map[i] == i for every cpu. cpu_number_map is
17  * used e.g. to find the idle task belonging to a logical cpu. Every array
18  * in the kernel is sorted by the logical cpu number and not by the physical
19  * one which is causing all the confusion with __cpu_logical_map and
20  * cpu_number_map in other architectures.
21  */
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/mm.h>
26 #include <linux/err.h>
27 #include <linux/spinlock.h>
28 #include <linux/kernel_stat.h>
29 #include <linux/delay.h>
30 #include <linux/cache.h>
31 #include <linux/interrupt.h>
32 #include <linux/cpu.h>
33 #include <linux/timex.h>
34 #include <linux/bootmem.h>
35 #include <asm/ipl.h>
36 #include <asm/setup.h>
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 #include <asm/timer.h>
44 #include <asm/lowcore.h>
45 
46 /*
47  * An array with a pointer the lowcore of every CPU.
48  */
49 struct _lowcore *lowcore_ptr[NR_CPUS];
50 EXPORT_SYMBOL(lowcore_ptr);
51 
52 cpumask_t cpu_online_map = CPU_MASK_NONE;
53 EXPORT_SYMBOL(cpu_online_map);
54 
55 cpumask_t cpu_possible_map = CPU_MASK_NONE;
56 EXPORT_SYMBOL(cpu_possible_map);
57 
58 static struct task_struct *current_set[NR_CPUS];
59 
60 static void smp_ext_bitcall(int, ec_bit_sig);
61 
62 /*
63  * Structure and data for __smp_call_function_map(). This is designed to
64  * minimise static memory requirements. It also looks cleaner.
65  */
66 static DEFINE_SPINLOCK(call_lock);
67 
68 struct call_data_struct {
69 	void (*func) (void *info);
70 	void *info;
71 	cpumask_t started;
72 	cpumask_t finished;
73 	int wait;
74 };
75 
76 static struct call_data_struct *call_data;
77 
78 /*
79  * 'Call function' interrupt callback
80  */
81 static void do_call_function(void)
82 {
83 	void (*func) (void *info) = call_data->func;
84 	void *info = call_data->info;
85 	int wait = call_data->wait;
86 
87 	cpu_set(smp_processor_id(), call_data->started);
88 	(*func)(info);
89 	if (wait)
90 		cpu_set(smp_processor_id(), call_data->finished);;
91 }
92 
93 static void __smp_call_function_map(void (*func) (void *info), void *info,
94 				    int nonatomic, int wait, cpumask_t map)
95 {
96 	struct call_data_struct data;
97 	int cpu, local = 0;
98 
99 	/*
100 	 * Can deadlock when interrupts are disabled or if in wrong context.
101 	 */
102 	WARN_ON(irqs_disabled() || in_irq());
103 
104 	/*
105 	 * Check for local function call. We have to have the same call order
106 	 * as in on_each_cpu() because of machine_restart_smp().
107 	 */
108 	if (cpu_isset(smp_processor_id(), map)) {
109 		local = 1;
110 		cpu_clear(smp_processor_id(), map);
111 	}
112 
113 	cpus_and(map, map, cpu_online_map);
114 	if (cpus_empty(map))
115 		goto out;
116 
117 	data.func = func;
118 	data.info = info;
119 	data.started = CPU_MASK_NONE;
120 	data.wait = wait;
121 	if (wait)
122 		data.finished = CPU_MASK_NONE;
123 
124 	spin_lock(&call_lock);
125 	call_data = &data;
126 
127 	for_each_cpu_mask(cpu, map)
128 		smp_ext_bitcall(cpu, ec_call_function);
129 
130 	/* Wait for response */
131 	while (!cpus_equal(map, data.started))
132 		cpu_relax();
133 	if (wait)
134 		while (!cpus_equal(map, data.finished))
135 			cpu_relax();
136 	spin_unlock(&call_lock);
137 out:
138 	if (local) {
139 		local_irq_disable();
140 		func(info);
141 		local_irq_enable();
142 	}
143 }
144 
145 /*
146  * smp_call_function:
147  * @func: the function to run; this must be fast and non-blocking
148  * @info: an arbitrary pointer to pass to the function
149  * @nonatomic: unused
150  * @wait: if true, wait (atomically) until function has completed on other CPUs
151  *
152  * Run a function on all other CPUs.
153  *
154  * You must not call this function with disabled interrupts, from a
155  * hardware interrupt handler or from a bottom half.
156  */
157 int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
158 		      int wait)
159 {
160 	cpumask_t map;
161 
162 	preempt_disable();
163 	map = cpu_online_map;
164 	cpu_clear(smp_processor_id(), map);
165 	__smp_call_function_map(func, info, nonatomic, wait, map);
166 	preempt_enable();
167 	return 0;
168 }
169 EXPORT_SYMBOL(smp_call_function);
170 
171 /*
172  * smp_call_function_single:
173  * @cpu: the CPU where func should run
174  * @func: the function to run; this must be fast and non-blocking
175  * @info: an arbitrary pointer to pass to the function
176  * @nonatomic: unused
177  * @wait: if true, wait (atomically) until function has completed on other CPUs
178  *
179  * Run a function on one processor.
180  *
181  * You must not call this function with disabled interrupts, from a
182  * hardware interrupt handler or from a bottom half.
183  */
184 int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
185 			     int nonatomic, int wait)
186 {
187 	preempt_disable();
188 	__smp_call_function_map(func, info, nonatomic, wait,
189 				cpumask_of_cpu(cpu));
190 	preempt_enable();
191 	return 0;
192 }
193 EXPORT_SYMBOL(smp_call_function_single);
194 
195 static void do_send_stop(void)
196 {
197 	int cpu, rc;
198 
199 	/* stop all processors */
200 	for_each_online_cpu(cpu) {
201 		if (cpu == smp_processor_id())
202 			continue;
203 		do {
204 			rc = signal_processor(cpu, sigp_stop);
205 		} while (rc == sigp_busy);
206 	}
207 }
208 
209 static void do_store_status(void)
210 {
211 	int cpu, rc;
212 
213 	/* store status of all processors in their lowcores (real 0) */
214 	for_each_online_cpu(cpu) {
215 		if (cpu == smp_processor_id())
216 			continue;
217 		do {
218 			rc = signal_processor_p(
219 				(__u32)(unsigned long) lowcore_ptr[cpu], cpu,
220 				sigp_store_status_at_address);
221 		} while (rc == sigp_busy);
222 	}
223 }
224 
225 static void do_wait_for_stop(void)
226 {
227 	int cpu;
228 
229 	/* Wait for all other cpus to enter stopped state */
230 	for_each_online_cpu(cpu) {
231 		if (cpu == smp_processor_id())
232 			continue;
233 		while (!smp_cpu_not_running(cpu))
234 			cpu_relax();
235 	}
236 }
237 
238 /*
239  * this function sends a 'stop' sigp to all other CPUs in the system.
240  * it goes straight through.
241  */
242 void smp_send_stop(void)
243 {
244 	/* Disable all interrupts/machine checks */
245 	__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
246 
247 	/* write magic number to zero page (absolute 0) */
248 	lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;
249 
250 	/* stop other processors. */
251 	do_send_stop();
252 
253 	/* wait until other processors are stopped */
254 	do_wait_for_stop();
255 
256 	/* store status of other processors. */
257 	do_store_status();
258 }
259 
260 /*
261  * Reboot, halt and power_off routines for SMP.
262  */
263 void machine_restart_smp(char *__unused)
264 {
265 	smp_send_stop();
266 	do_reipl();
267 }
268 
269 void machine_halt_smp(void)
270 {
271 	smp_send_stop();
272 	if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)
273 		__cpcmd(vmhalt_cmd, NULL, 0, NULL);
274 	signal_processor(smp_processor_id(), sigp_stop_and_store_status);
275 	for (;;);
276 }
277 
278 void machine_power_off_smp(void)
279 {
280 	smp_send_stop();
281 	if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)
282 		__cpcmd(vmpoff_cmd, NULL, 0, NULL);
283 	signal_processor(smp_processor_id(), sigp_stop_and_store_status);
284 	for (;;);
285 }
286 
287 /*
288  * This is the main routine where commands issued by other
289  * cpus are handled.
290  */
291 
292 static void do_ext_call_interrupt(__u16 code)
293 {
294 	unsigned long bits;
295 
296 	/*
297 	 * handle bit signal external calls
298 	 *
299 	 * For the ec_schedule signal we have to do nothing. All the work
300 	 * is done automatically when we return from the interrupt.
301 	 */
302 	bits = xchg(&S390_lowcore.ext_call_fast, 0);
303 
304 	if (test_bit(ec_call_function, &bits))
305 		do_call_function();
306 }
307 
308 /*
309  * Send an external call sigp to another cpu and return without waiting
310  * for its completion.
311  */
312 static void smp_ext_bitcall(int cpu, ec_bit_sig sig)
313 {
314 	/*
315 	 * Set signaling bit in lowcore of target cpu and kick it
316 	 */
317 	set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
318 	while (signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
319 		udelay(10);
320 }
321 
322 #ifndef CONFIG_64BIT
323 /*
324  * this function sends a 'purge tlb' signal to another CPU.
325  */
326 void smp_ptlb_callback(void *info)
327 {
328 	local_flush_tlb();
329 }
330 
331 void smp_ptlb_all(void)
332 {
333 	on_each_cpu(smp_ptlb_callback, NULL, 0, 1);
334 }
335 EXPORT_SYMBOL(smp_ptlb_all);
336 #endif /* ! CONFIG_64BIT */
337 
338 /*
339  * this function sends a 'reschedule' IPI to another CPU.
340  * it goes straight through and wastes no time serializing
341  * anything. Worst case is that we lose a reschedule ...
342  */
343 void smp_send_reschedule(int cpu)
344 {
345 	smp_ext_bitcall(cpu, ec_schedule);
346 }
347 
348 /*
349  * parameter area for the set/clear control bit callbacks
350  */
351 struct ec_creg_mask_parms {
352 	unsigned long orvals[16];
353 	unsigned long andvals[16];
354 };
355 
356 /*
357  * callback for setting/clearing control bits
358  */
359 static void smp_ctl_bit_callback(void *info)
360 {
361 	struct ec_creg_mask_parms *pp = info;
362 	unsigned long cregs[16];
363 	int i;
364 
365 	__ctl_store(cregs, 0, 15);
366 	for (i = 0; i <= 15; i++)
367 		cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
368 	__ctl_load(cregs, 0, 15);
369 }
370 
371 /*
372  * Set a bit in a control register of all cpus
373  */
374 void smp_ctl_set_bit(int cr, int bit)
375 {
376 	struct ec_creg_mask_parms parms;
377 
378 	memset(&parms.orvals, 0, sizeof(parms.orvals));
379 	memset(&parms.andvals, 0xff, sizeof(parms.andvals));
380 	parms.orvals[cr] = 1 << bit;
381 	on_each_cpu(smp_ctl_bit_callback, &parms, 0, 1);
382 }
383 EXPORT_SYMBOL(smp_ctl_set_bit);
384 
385 /*
386  * Clear a bit in a control register of all cpus
387  */
388 void smp_ctl_clear_bit(int cr, int bit)
389 {
390 	struct ec_creg_mask_parms parms;
391 
392 	memset(&parms.orvals, 0, sizeof(parms.orvals));
393 	memset(&parms.andvals, 0xff, sizeof(parms.andvals));
394 	parms.andvals[cr] = ~(1L << bit);
395 	on_each_cpu(smp_ctl_bit_callback, &parms, 0, 1);
396 }
397 EXPORT_SYMBOL(smp_ctl_clear_bit);
398 
399 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_ZFCPDUMP_MODULE)
400 
401 /*
402  * zfcpdump_prefix_array holds prefix registers for the following scenario:
403  * 64 bit zfcpdump kernel and 31 bit kernel which is to be dumped. We have to
404  * save its prefix registers, since they get lost, when switching from 31 bit
405  * to 64 bit.
406  */
407 unsigned int zfcpdump_prefix_array[NR_CPUS + 1] \
408 	__attribute__((__section__(".data")));
409 
410 static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
411 {
412 	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
413 		return;
414 	if (cpu >= NR_CPUS) {
415 		printk(KERN_WARNING "Registers for cpu %i not saved since dump "
416 		       "kernel was compiled with NR_CPUS=%i\n", cpu, NR_CPUS);
417 		return;
418 	}
419 	zfcpdump_save_areas[cpu] = alloc_bootmem(sizeof(union save_area));
420 	__cpu_logical_map[1] = (__u16) phy_cpu;
421 	while (signal_processor(1, sigp_stop_and_store_status) == sigp_busy)
422 		cpu_relax();
423 	memcpy(zfcpdump_save_areas[cpu],
424 	       (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
425 	       SAVE_AREA_SIZE);
426 #ifdef CONFIG_64BIT
427 	/* copy original prefix register */
428 	zfcpdump_save_areas[cpu]->s390x.pref_reg = zfcpdump_prefix_array[cpu];
429 #endif
430 }
431 
432 union save_area *zfcpdump_save_areas[NR_CPUS + 1];
433 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
434 
435 #else
436 
437 static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }
438 
439 #endif /* CONFIG_ZFCPDUMP || CONFIG_ZFCPDUMP_MODULE */
440 
441 /*
442  * Lets check how many CPUs we have.
443  */
444 static unsigned int __init smp_count_cpus(void)
445 {
446 	unsigned int cpu, num_cpus;
447 	__u16 boot_cpu_addr;
448 
449 	/*
450 	 * cpu 0 is the boot cpu. See smp_prepare_boot_cpu.
451 	 */
452 	boot_cpu_addr = S390_lowcore.cpu_data.cpu_addr;
453 	current_thread_info()->cpu = 0;
454 	num_cpus = 1;
455 	for (cpu = 0; cpu <= 65535; cpu++) {
456 		if ((__u16) cpu == boot_cpu_addr)
457 			continue;
458 		__cpu_logical_map[1] = (__u16) cpu;
459 		if (signal_processor(1, sigp_sense) == sigp_not_operational)
460 			continue;
461 		smp_get_save_area(num_cpus, cpu);
462 		num_cpus++;
463 	}
464 	printk("Detected %d CPU's\n", (int) num_cpus);
465 	printk("Boot cpu address %2X\n", boot_cpu_addr);
466 	return num_cpus;
467 }
468 
469 /*
470  *	Activate a secondary processor.
471  */
472 int __cpuinit start_secondary(void *cpuvoid)
473 {
474 	/* Setup the cpu */
475 	cpu_init();
476 	preempt_disable();
477 	/* Enable TOD clock interrupts on the secondary cpu. */
478 	init_cpu_timer();
479 #ifdef CONFIG_VIRT_TIMER
480 	/* Enable cpu timer interrupts on the secondary cpu. */
481 	init_cpu_vtimer();
482 #endif
483 	/* Enable pfault pseudo page faults on this cpu. */
484 	pfault_init();
485 
486 	/* Mark this cpu as online */
487 	cpu_set(smp_processor_id(), cpu_online_map);
488 	/* Switch on interrupts */
489 	local_irq_enable();
490 	/* Print info about this processor */
491 	print_cpu_info(&S390_lowcore.cpu_data);
492 	/* cpu_idle will call schedule for us */
493 	cpu_idle();
494 	return 0;
495 }
496 
497 static void __init smp_create_idle(unsigned int cpu)
498 {
499 	struct task_struct *p;
500 
501 	/*
502 	 *  don't care about the psw and regs settings since we'll never
503 	 *  reschedule the forked task.
504 	 */
505 	p = fork_idle(cpu);
506 	if (IS_ERR(p))
507 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
508 	current_set[cpu] = p;
509 }
510 
511 static int cpu_stopped(int cpu)
512 {
513 	__u32 status;
514 
515 	/* Check for stopped state */
516 	if (signal_processor_ps(&status, 0, cpu, sigp_sense) ==
517 	    sigp_status_stored) {
518 		if (status & 0x40)
519 			return 1;
520 	}
521 	return 0;
522 }
523 
524 /* Upping and downing of CPUs */
525 
526 int __cpu_up(unsigned int cpu)
527 {
528 	struct task_struct *idle;
529 	struct _lowcore *cpu_lowcore;
530 	struct stack_frame *sf;
531 	sigp_ccode ccode;
532 	int curr_cpu;
533 
534 	for (curr_cpu = 0; curr_cpu <= 65535; curr_cpu++) {
535 		__cpu_logical_map[cpu] = (__u16) curr_cpu;
536 		if (cpu_stopped(cpu))
537 			break;
538 	}
539 
540 	if (!cpu_stopped(cpu))
541 		return -ENODEV;
542 
543 	ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
544 				   cpu, sigp_set_prefix);
545 	if (ccode) {
546 		printk("sigp_set_prefix failed for cpu %d "
547 		       "with condition code %d\n",
548 		       (int) cpu, (int) ccode);
549 		return -EIO;
550 	}
551 
552 	idle = current_set[cpu];
553 	cpu_lowcore = lowcore_ptr[cpu];
554 	cpu_lowcore->kernel_stack = (unsigned long)
555 		task_stack_page(idle) + THREAD_SIZE;
556 	sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
557 				     - sizeof(struct pt_regs)
558 				     - sizeof(struct stack_frame));
559 	memset(sf, 0, sizeof(struct stack_frame));
560 	sf->gprs[9] = (unsigned long) sf;
561 	cpu_lowcore->save_area[15] = (unsigned long) sf;
562 	__ctl_store(cpu_lowcore->cregs_save_area[0], 0, 15);
563 	asm volatile(
564 		"	stam	0,15,0(%0)"
565 		: : "a" (&cpu_lowcore->access_regs_save_area) : "memory");
566 	cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
567 	cpu_lowcore->current_task = (unsigned long) idle;
568 	cpu_lowcore->cpu_data.cpu_nr = cpu;
569 	eieio();
570 
571 	while (signal_processor(cpu, sigp_restart) == sigp_busy)
572 		udelay(10);
573 
574 	while (!cpu_online(cpu))
575 		cpu_relax();
576 	return 0;
577 }
578 
579 static unsigned int __initdata additional_cpus;
580 static unsigned int __initdata possible_cpus;
581 
582 void __init smp_setup_cpu_possible_map(void)
583 {
584 	unsigned int phy_cpus, pos_cpus, cpu;
585 
586 	phy_cpus = smp_count_cpus();
587 	pos_cpus = min(phy_cpus + additional_cpus, (unsigned int) NR_CPUS);
588 
589 	if (possible_cpus)
590 		pos_cpus = min(possible_cpus, (unsigned int) NR_CPUS);
591 
592 	for (cpu = 0; cpu < pos_cpus; cpu++)
593 		cpu_set(cpu, cpu_possible_map);
594 
595 	phy_cpus = min(phy_cpus, pos_cpus);
596 
597 	for (cpu = 0; cpu < phy_cpus; cpu++)
598 		cpu_set(cpu, cpu_present_map);
599 }
600 
601 #ifdef CONFIG_HOTPLUG_CPU
602 
603 static int __init setup_additional_cpus(char *s)
604 {
605 	additional_cpus = simple_strtoul(s, NULL, 0);
606 	return 0;
607 }
608 early_param("additional_cpus", setup_additional_cpus);
609 
610 static int __init setup_possible_cpus(char *s)
611 {
612 	possible_cpus = simple_strtoul(s, NULL, 0);
613 	return 0;
614 }
615 early_param("possible_cpus", setup_possible_cpus);
616 
617 int __cpu_disable(void)
618 {
619 	struct ec_creg_mask_parms cr_parms;
620 	int cpu = smp_processor_id();
621 
622 	cpu_clear(cpu, cpu_online_map);
623 
624 	/* Disable pfault pseudo page faults on this cpu. */
625 	pfault_fini();
626 
627 	memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));
628 	memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));
629 
630 	/* disable all external interrupts */
631 	cr_parms.orvals[0] = 0;
632 	cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 12 |
633 				1 << 11 | 1 << 10 | 1 <<  6 | 1 <<  4);
634 	/* disable all I/O interrupts */
635 	cr_parms.orvals[6] = 0;
636 	cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |
637 				1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);
638 	/* disable most machine checks */
639 	cr_parms.orvals[14] = 0;
640 	cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |
641 				 1 << 25 | 1 << 24);
642 
643 	smp_ctl_bit_callback(&cr_parms);
644 
645 	return 0;
646 }
647 
648 void __cpu_die(unsigned int cpu)
649 {
650 	/* Wait until target cpu is down */
651 	while (!smp_cpu_not_running(cpu))
652 		cpu_relax();
653 	printk("Processor %d spun down\n", cpu);
654 }
655 
656 void cpu_die(void)
657 {
658 	idle_task_exit();
659 	signal_processor(smp_processor_id(), sigp_stop);
660 	BUG();
661 	for (;;);
662 }
663 
664 #endif /* CONFIG_HOTPLUG_CPU */
665 
666 /*
667  *	Cycle through the processors and setup structures.
668  */
669 
670 void __init smp_prepare_cpus(unsigned int max_cpus)
671 {
672 	unsigned long stack;
673 	unsigned int cpu;
674 	int i;
675 
676 	/* request the 0x1201 emergency signal external interrupt */
677 	if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
678 		panic("Couldn't request external interrupt 0x1201");
679 	memset(lowcore_ptr, 0, sizeof(lowcore_ptr));
680 	/*
681 	 *  Initialize prefix pages and stacks for all possible cpus
682 	 */
683 	print_cpu_info(&S390_lowcore.cpu_data);
684 
685 	for_each_possible_cpu(i) {
686 		lowcore_ptr[i] = (struct _lowcore *)
687 			__get_free_pages(GFP_KERNEL | GFP_DMA,
688 					 sizeof(void*) == 8 ? 1 : 0);
689 		stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
690 		if (!lowcore_ptr[i] || !stack)
691 			panic("smp_boot_cpus failed to allocate memory\n");
692 
693 		*(lowcore_ptr[i]) = S390_lowcore;
694 		lowcore_ptr[i]->async_stack = stack + ASYNC_SIZE;
695 		stack = __get_free_pages(GFP_KERNEL, 0);
696 		if (!stack)
697 			panic("smp_boot_cpus failed to allocate memory\n");
698 		lowcore_ptr[i]->panic_stack = stack + PAGE_SIZE;
699 #ifndef CONFIG_64BIT
700 		if (MACHINE_HAS_IEEE) {
701 			lowcore_ptr[i]->extended_save_area_addr =
702 				(__u32) __get_free_pages(GFP_KERNEL, 0);
703 			if (!lowcore_ptr[i]->extended_save_area_addr)
704 				panic("smp_boot_cpus failed to "
705 				      "allocate memory\n");
706 		}
707 #endif
708 	}
709 #ifndef CONFIG_64BIT
710 	if (MACHINE_HAS_IEEE)
711 		ctl_set_bit(14, 29); /* enable extended save area */
712 #endif
713 	set_prefix((u32)(unsigned long) lowcore_ptr[smp_processor_id()]);
714 
715 	for_each_possible_cpu(cpu)
716 		if (cpu != smp_processor_id())
717 			smp_create_idle(cpu);
718 }
719 
720 void __init smp_prepare_boot_cpu(void)
721 {
722 	BUG_ON(smp_processor_id() != 0);
723 
724 	cpu_set(0, cpu_online_map);
725 	S390_lowcore.percpu_offset = __per_cpu_offset[0];
726 	current_set[0] = current;
727 }
728 
729 void __init smp_cpus_done(unsigned int max_cpus)
730 {
731 	cpu_present_map = cpu_possible_map;
732 }
733 
734 /*
735  * the frequency of the profiling timer can be changed
736  * by writing a multiplier value into /proc/profile.
737  *
738  * usually you want to run this on all CPUs ;)
739  */
740 int setup_profiling_timer(unsigned int multiplier)
741 {
742 	return 0;
743 }
744 
745 static DEFINE_PER_CPU(struct cpu, cpu_devices);
746 
747 static ssize_t show_capability(struct sys_device *dev, char *buf)
748 {
749 	unsigned int capability;
750 	int rc;
751 
752 	rc = get_cpu_capability(&capability);
753 	if (rc)
754 		return rc;
755 	return sprintf(buf, "%u\n", capability);
756 }
757 static SYSDEV_ATTR(capability, 0444, show_capability, NULL);
758 
759 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
760 				    unsigned long action, void *hcpu)
761 {
762 	unsigned int cpu = (unsigned int)(long)hcpu;
763 	struct cpu *c = &per_cpu(cpu_devices, cpu);
764 	struct sys_device *s = &c->sysdev;
765 
766 	switch (action) {
767 	case CPU_ONLINE:
768 	case CPU_ONLINE_FROZEN:
769 		if (sysdev_create_file(s, &attr_capability))
770 			return NOTIFY_BAD;
771 		break;
772 	case CPU_DEAD:
773 	case CPU_DEAD_FROZEN:
774 		sysdev_remove_file(s, &attr_capability);
775 		break;
776 	}
777 	return NOTIFY_OK;
778 }
779 
780 static struct notifier_block __cpuinitdata smp_cpu_nb = {
781 	.notifier_call = smp_cpu_notify,
782 };
783 
784 static int __init topology_init(void)
785 {
786 	int cpu;
787 
788 	register_cpu_notifier(&smp_cpu_nb);
789 
790 	for_each_possible_cpu(cpu) {
791 		struct cpu *c = &per_cpu(cpu_devices, cpu);
792 		struct sys_device *s = &c->sysdev;
793 
794 		c->hotpluggable = 1;
795 		register_cpu(c, cpu);
796 		if (!cpu_online(cpu))
797 			continue;
798 		s = &c->sysdev;
799 		sysdev_create_file(s, &attr_capability);
800 	}
801 	return 0;
802 }
803 subsys_initcall(topology_init);
804