Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
[linux-2.6.git] / arch / s390 / kernel / smp.c
1 /*
2  *  SMP related functions
3  *
4  *    Copyright IBM Corp. 1999,2012
5  *    Author(s): Denis Joseph Barrow,
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  * The code outside of smp.c uses logical cpu numbers, only smp.c does
14  * the translation of logical to physical cpu ids. All new code that
15  * operates on physical cpu numbers needs to go into smp.c.
16  */
17
18 #define KMSG_COMPONENT "cpu"
19 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
20
21 #include <linux/workqueue.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/mm.h>
25 #include <linux/err.h>
26 #include <linux/spinlock.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/delay.h>
29 #include <linux/interrupt.h>
30 #include <linux/irqflags.h>
31 #include <linux/cpu.h>
32 #include <linux/slab.h>
33 #include <linux/crash_dump.h>
34 #include <asm/asm-offsets.h>
35 #include <asm/ipl.h>
36 #include <asm/setup.h>
37 #include <asm/irq.h>
38 #include <asm/tlbflush.h>
39 #include <asm/timer.h>
40 #include <asm/lowcore.h>
41 #include <asm/sclp.h>
42 #include <asm/vdso.h>
43 #include <asm/debug.h>
44 #include <asm/os_info.h>
45 #include "entry.h"
46
47 enum {
48         sigp_sense = 1,
49         sigp_external_call = 2,
50         sigp_emergency_signal = 3,
51         sigp_start = 4,
52         sigp_stop = 5,
53         sigp_restart = 6,
54         sigp_stop_and_store_status = 9,
55         sigp_initial_cpu_reset = 11,
56         sigp_cpu_reset = 12,
57         sigp_set_prefix = 13,
58         sigp_store_status_at_address = 14,
59         sigp_store_extended_status_at_address = 15,
60         sigp_set_architecture = 18,
61         sigp_conditional_emergency_signal = 19,
62         sigp_sense_running = 21,
63 };
64
65 enum {
66         sigp_order_code_accepted = 0,
67         sigp_status_stored = 1,
68         sigp_busy = 2,
69         sigp_not_operational = 3,
70 };
71
72 enum {
73         ec_schedule = 0,
74         ec_call_function,
75         ec_call_function_single,
76         ec_stop_cpu,
77 };
78
79 enum {
80         CPU_STATE_STANDBY,
81         CPU_STATE_CONFIGURED,
82 };
83
84 struct pcpu {
85         struct cpu cpu;
86         struct task_struct *idle;       /* idle process for the cpu */
87         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
88         unsigned long async_stack;      /* async stack for the cpu */
89         unsigned long panic_stack;      /* panic stack for the cpu */
90         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
91         int state;                      /* physical cpu state */
92         u32 status;                     /* last status received via sigp */
93         u16 address;                    /* physical cpu address */
94 };
95
96 static u8 boot_cpu_type;
97 static u16 boot_cpu_address;
98 static struct pcpu pcpu_devices[NR_CPUS];
99
100 DEFINE_MUTEX(smp_cpu_state_mutex);
101
102 /*
103  * Signal processor helper functions.
104  */
105 static inline int __pcpu_sigp(u16 addr, u8 order, u32 parm, u32 *status)
106 {
107         register unsigned int reg1 asm ("1") = parm;
108         int cc;
109
110         asm volatile(
111                 "       sigp    %1,%2,0(%3)\n"
112                 "       ipm     %0\n"
113                 "       srl     %0,28\n"
114                 : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
115         if (status && cc == 1)
116                 *status = reg1;
117         return cc;
118 }
119
120 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
121 {
122         int cc;
123
124         while (1) {
125                 cc = __pcpu_sigp(addr, order, parm, status);
126                 if (cc != sigp_busy)
127                         return cc;
128                 cpu_relax();
129         }
130 }
131
132 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
133 {
134         int cc, retry;
135
136         for (retry = 0; ; retry++) {
137                 cc = __pcpu_sigp(pcpu->address, order, parm, &pcpu->status);
138                 if (cc != sigp_busy)
139                         break;
140                 if (retry >= 3)
141                         udelay(10);
142         }
143         return cc;
144 }
145
146 static inline int pcpu_stopped(struct pcpu *pcpu)
147 {
148         if (__pcpu_sigp(pcpu->address, sigp_sense,
149                         0, &pcpu->status) != sigp_status_stored)
150                 return 0;
151         /* Check for stopped and check stop state */
152         return !!(pcpu->status & 0x50);
153 }
154
155 static inline int pcpu_running(struct pcpu *pcpu)
156 {
157         if (__pcpu_sigp(pcpu->address, sigp_sense_running,
158                         0, &pcpu->status) != sigp_status_stored)
159                 return 1;
160         /* Check for running status */
161         return !(pcpu->status & 0x400);
162 }
163
164 /*
165  * Find struct pcpu by cpu address.
166  */
167 static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
168 {
169         int cpu;
170
171         for_each_cpu(cpu, mask)
172                 if (pcpu_devices[cpu].address == address)
173                         return pcpu_devices + cpu;
174         return NULL;
175 }
176
177 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
178 {
179         int order;
180
181         set_bit(ec_bit, &pcpu->ec_mask);
182         order = pcpu_running(pcpu) ?
183                 sigp_external_call : sigp_emergency_signal;
184         pcpu_sigp_retry(pcpu, order, 0);
185 }
186
187 static int __cpuinit pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
188 {
189         struct _lowcore *lc;
190
191         if (pcpu != &pcpu_devices[0]) {
192                 pcpu->lowcore = (struct _lowcore *)
193                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
194                 pcpu->async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
195                 pcpu->panic_stack = __get_free_page(GFP_KERNEL);
196                 if (!pcpu->lowcore || !pcpu->panic_stack || !pcpu->async_stack)
197                         goto out;
198         }
199         lc = pcpu->lowcore;
200         memcpy(lc, &S390_lowcore, 512);
201         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
202         lc->async_stack = pcpu->async_stack + ASYNC_SIZE;
203         lc->panic_stack = pcpu->panic_stack + PAGE_SIZE;
204         lc->cpu_nr = cpu;
205 #ifndef CONFIG_64BIT
206         if (MACHINE_HAS_IEEE) {
207                 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
208                 if (!lc->extended_save_area_addr)
209                         goto out;
210         }
211 #else
212         if (vdso_alloc_per_cpu(lc))
213                 goto out;
214 #endif
215         lowcore_ptr[cpu] = lc;
216         pcpu_sigp_retry(pcpu, sigp_set_prefix, (u32)(unsigned long) lc);
217         return 0;
218 out:
219         if (pcpu != &pcpu_devices[0]) {
220                 free_page(pcpu->panic_stack);
221                 free_pages(pcpu->async_stack, ASYNC_ORDER);
222                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
223         }
224         return -ENOMEM;
225 }
226
227 static void pcpu_free_lowcore(struct pcpu *pcpu)
228 {
229         pcpu_sigp_retry(pcpu, sigp_set_prefix, 0);
230         lowcore_ptr[pcpu - pcpu_devices] = NULL;
231 #ifndef CONFIG_64BIT
232         if (MACHINE_HAS_IEEE) {
233                 struct _lowcore *lc = pcpu->lowcore;
234
235                 free_page((unsigned long) lc->extended_save_area_addr);
236                 lc->extended_save_area_addr = 0;
237         }
238 #else
239         vdso_free_per_cpu(pcpu->lowcore);
240 #endif
241         if (pcpu != &pcpu_devices[0]) {
242                 free_page(pcpu->panic_stack);
243                 free_pages(pcpu->async_stack, ASYNC_ORDER);
244                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
245         }
246 }
247
248 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
249 {
250         struct _lowcore *lc = pcpu->lowcore;
251
252         atomic_inc(&init_mm.context.attach_count);
253         lc->cpu_nr = cpu;
254         lc->percpu_offset = __per_cpu_offset[cpu];
255         lc->kernel_asce = S390_lowcore.kernel_asce;
256         lc->machine_flags = S390_lowcore.machine_flags;
257         lc->ftrace_func = S390_lowcore.ftrace_func;
258         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
259         __ctl_store(lc->cregs_save_area, 0, 15);
260         save_access_regs((unsigned int *) lc->access_regs_save_area);
261         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
262                MAX_FACILITY_BIT/8);
263 }
264
265 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
266 {
267         struct _lowcore *lc = pcpu->lowcore;
268         struct thread_info *ti = task_thread_info(tsk);
269
270         lc->kernel_stack = (unsigned long) task_stack_page(tsk) + THREAD_SIZE;
271         lc->thread_info = (unsigned long) task_thread_info(tsk);
272         lc->current_task = (unsigned long) tsk;
273         lc->user_timer = ti->user_timer;
274         lc->system_timer = ti->system_timer;
275         lc->steal_timer = 0;
276 }
277
278 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
279 {
280         struct _lowcore *lc = pcpu->lowcore;
281
282         lc->restart_stack = lc->kernel_stack;
283         lc->restart_fn = (unsigned long) func;
284         lc->restart_data = (unsigned long) data;
285         lc->restart_source = -1UL;
286         pcpu_sigp_retry(pcpu, sigp_restart, 0);
287 }
288
289 /*
290  * Call function via PSW restart on pcpu and stop the current cpu.
291  */
292 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
293                           void *data, unsigned long stack)
294 {
295         struct _lowcore *lc = pcpu->lowcore;
296         unsigned short this_cpu;
297
298         __load_psw_mask(psw_kernel_bits);
299         this_cpu = stap();
300         if (pcpu->address == this_cpu)
301                 func(data);     /* should not return */
302         /* Stop target cpu (if func returns this stops the current cpu). */
303         pcpu_sigp_retry(pcpu, sigp_stop, 0);
304         /* Restart func on the target cpu and stop the current cpu. */
305         lc->restart_stack = stack;
306         lc->restart_fn = (unsigned long) func;
307         lc->restart_data = (unsigned long) data;
308         lc->restart_source = (unsigned long) this_cpu;
309         asm volatile(
310                 "0:     sigp    0,%0,6  # sigp restart to target cpu\n"
311                 "       brc     2,0b    # busy, try again\n"
312                 "1:     sigp    0,%1,5  # sigp stop to current cpu\n"
313                 "       brc     2,1b    # busy, try again\n"
314                 : : "d" (pcpu->address), "d" (this_cpu) : "0", "1", "cc");
315         for (;;) ;
316 }
317
318 /*
319  * Call function on an online CPU.
320  */
321 void smp_call_online_cpu(void (*func)(void *), void *data)
322 {
323         struct pcpu *pcpu;
324
325         /* Use the current cpu if it is online. */
326         pcpu = pcpu_find_address(cpu_online_mask, stap());
327         if (!pcpu)
328                 /* Use the first online cpu. */
329                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
330         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
331 }
332
333 /*
334  * Call function on the ipl CPU.
335  */
336 void smp_call_ipl_cpu(void (*func)(void *), void *data)
337 {
338         pcpu_delegate(&pcpu_devices[0], func, data,
339                       pcpu_devices->panic_stack + PAGE_SIZE);
340 }
341
342 int smp_find_processor_id(u16 address)
343 {
344         int cpu;
345
346         for_each_present_cpu(cpu)
347                 if (pcpu_devices[cpu].address == address)
348                         return cpu;
349         return -1;
350 }
351
352 int smp_vcpu_scheduled(int cpu)
353 {
354         return pcpu_running(pcpu_devices + cpu);
355 }
356
357 void smp_yield(void)
358 {
359         if (MACHINE_HAS_DIAG44)
360                 asm volatile("diag 0,0,0x44");
361 }
362
363 void smp_yield_cpu(int cpu)
364 {
365         if (MACHINE_HAS_DIAG9C)
366                 asm volatile("diag %0,0,0x9c"
367                              : : "d" (pcpu_devices[cpu].address));
368         else if (MACHINE_HAS_DIAG44)
369                 asm volatile("diag 0,0,0x44");
370 }
371
372 /*
373  * Send cpus emergency shutdown signal. This gives the cpus the
374  * opportunity to complete outstanding interrupts.
375  */
376 void smp_emergency_stop(cpumask_t *cpumask)
377 {
378         u64 end;
379         int cpu;
380
381         end = get_clock() + (1000000UL << 12);
382         for_each_cpu(cpu, cpumask) {
383                 struct pcpu *pcpu = pcpu_devices + cpu;
384                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
385                 while (__pcpu_sigp(pcpu->address, sigp_emergency_signal,
386                                    0, NULL) == sigp_busy &&
387                        get_clock() < end)
388                         cpu_relax();
389         }
390         while (get_clock() < end) {
391                 for_each_cpu(cpu, cpumask)
392                         if (pcpu_stopped(pcpu_devices + cpu))
393                                 cpumask_clear_cpu(cpu, cpumask);
394                 if (cpumask_empty(cpumask))
395                         break;
396                 cpu_relax();
397         }
398 }
399
400 /*
401  * Stop all cpus but the current one.
402  */
403 void smp_send_stop(void)
404 {
405         cpumask_t cpumask;
406         int cpu;
407
408         /* Disable all interrupts/machine checks */
409         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
410         trace_hardirqs_off();
411
412         debug_set_critical();
413         cpumask_copy(&cpumask, cpu_online_mask);
414         cpumask_clear_cpu(smp_processor_id(), &cpumask);
415
416         if (oops_in_progress)
417                 smp_emergency_stop(&cpumask);
418
419         /* stop all processors */
420         for_each_cpu(cpu, &cpumask) {
421                 struct pcpu *pcpu = pcpu_devices + cpu;
422                 pcpu_sigp_retry(pcpu, sigp_stop, 0);
423                 while (!pcpu_stopped(pcpu))
424                         cpu_relax();
425         }
426 }
427
428 /*
429  * Stop the current cpu.
430  */
431 void smp_stop_cpu(void)
432 {
433         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), sigp_stop, 0);
434         for (;;) ;
435 }
436
437 /*
438  * This is the main routine where commands issued by other
439  * cpus are handled.
440  */
441 static void do_ext_call_interrupt(struct ext_code ext_code,
442                                   unsigned int param32, unsigned long param64)
443 {
444         unsigned long bits;
445         int cpu;
446
447         cpu = smp_processor_id();
448         if (ext_code.code == 0x1202)
449                 kstat_cpu(cpu).irqs[EXTINT_EXC]++;
450         else
451                 kstat_cpu(cpu).irqs[EXTINT_EMS]++;
452         /*
453          * handle bit signal external calls
454          */
455         bits = xchg(&pcpu_devices[cpu].ec_mask, 0);
456
457         if (test_bit(ec_stop_cpu, &bits))
458                 smp_stop_cpu();
459
460         if (test_bit(ec_schedule, &bits))
461                 scheduler_ipi();
462
463         if (test_bit(ec_call_function, &bits))
464                 generic_smp_call_function_interrupt();
465
466         if (test_bit(ec_call_function_single, &bits))
467                 generic_smp_call_function_single_interrupt();
468
469 }
470
471 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
472 {
473         int cpu;
474
475         for_each_cpu(cpu, mask)
476                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function);
477 }
478
479 void arch_send_call_function_single_ipi(int cpu)
480 {
481         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
482 }
483
484 #ifndef CONFIG_64BIT
485 /*
486  * this function sends a 'purge tlb' signal to another CPU.
487  */
488 static void smp_ptlb_callback(void *info)
489 {
490         __tlb_flush_local();
491 }
492
493 void smp_ptlb_all(void)
494 {
495         on_each_cpu(smp_ptlb_callback, NULL, 1);
496 }
497 EXPORT_SYMBOL(smp_ptlb_all);
498 #endif /* ! CONFIG_64BIT */
499
500 /*
501  * this function sends a 'reschedule' IPI to another CPU.
502  * it goes straight through and wastes no time serializing
503  * anything. Worst case is that we lose a reschedule ...
504  */
505 void smp_send_reschedule(int cpu)
506 {
507         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
508 }
509
510 /*
511  * parameter area for the set/clear control bit callbacks
512  */
513 struct ec_creg_mask_parms {
514         unsigned long orval;
515         unsigned long andval;
516         int cr;
517 };
518
519 /*
520  * callback for setting/clearing control bits
521  */
522 static void smp_ctl_bit_callback(void *info)
523 {
524         struct ec_creg_mask_parms *pp = info;
525         unsigned long cregs[16];
526
527         __ctl_store(cregs, 0, 15);
528         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
529         __ctl_load(cregs, 0, 15);
530 }
531
532 /*
533  * Set a bit in a control register of all cpus
534  */
535 void smp_ctl_set_bit(int cr, int bit)
536 {
537         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
538
539         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
540 }
541 EXPORT_SYMBOL(smp_ctl_set_bit);
542
543 /*
544  * Clear a bit in a control register of all cpus
545  */
546 void smp_ctl_clear_bit(int cr, int bit)
547 {
548         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
549
550         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
551 }
552 EXPORT_SYMBOL(smp_ctl_clear_bit);
553
554 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
555
556 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
557 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
558
559 static void __init smp_get_save_area(int cpu, u16 address)
560 {
561         void *lc = pcpu_devices[0].lowcore;
562         struct save_area *save_area;
563
564         if (is_kdump_kernel())
565                 return;
566         if (!OLDMEM_BASE && (address == boot_cpu_address ||
567                              ipl_info.type != IPL_TYPE_FCP_DUMP))
568                 return;
569         if (cpu >= NR_CPUS) {
570                 pr_warning("CPU %i exceeds the maximum %i and is excluded "
571                            "from the dump\n", cpu, NR_CPUS - 1);
572                 return;
573         }
574         save_area = kmalloc(sizeof(struct save_area), GFP_KERNEL);
575         if (!save_area)
576                 panic("could not allocate memory for save area\n");
577         zfcpdump_save_areas[cpu] = save_area;
578 #ifdef CONFIG_CRASH_DUMP
579         if (address == boot_cpu_address) {
580                 /* Copy the registers of the boot cpu. */
581                 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
582                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
583                 return;
584         }
585 #endif
586         /* Get the registers of a non-boot cpu. */
587         __pcpu_sigp_relax(address, sigp_stop_and_store_status, 0, NULL);
588         memcpy_real(save_area, lc + SAVE_AREA_BASE, sizeof(*save_area));
589 }
590
591 int smp_store_status(int cpu)
592 {
593         struct pcpu *pcpu;
594
595         pcpu = pcpu_devices + cpu;
596         if (__pcpu_sigp_relax(pcpu->address, sigp_stop_and_store_status,
597                               0, NULL) != sigp_order_code_accepted)
598                 return -EIO;
599         return 0;
600 }
601
602 #else /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
603
604 static inline void smp_get_save_area(int cpu, u16 address) { }
605
606 #endif /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
607
608 static struct sclp_cpu_info *smp_get_cpu_info(void)
609 {
610         static int use_sigp_detection;
611         struct sclp_cpu_info *info;
612         int address;
613
614         info = kzalloc(sizeof(*info), GFP_KERNEL);
615         if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
616                 use_sigp_detection = 1;
617                 for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
618                         if (__pcpu_sigp_relax(address, sigp_sense, 0, NULL) ==
619                             sigp_not_operational)
620                                 continue;
621                         info->cpu[info->configured].address = address;
622                         info->configured++;
623                 }
624                 info->combined = info->configured;
625         }
626         return info;
627 }
628
629 static int __devinit smp_add_present_cpu(int cpu);
630
631 static int __devinit __smp_rescan_cpus(struct sclp_cpu_info *info,
632                                        int sysfs_add)
633 {
634         struct pcpu *pcpu;
635         cpumask_t avail;
636         int cpu, nr, i;
637
638         nr = 0;
639         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
640         cpu = cpumask_first(&avail);
641         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
642                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
643                         continue;
644                 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
645                         continue;
646                 pcpu = pcpu_devices + cpu;
647                 pcpu->address = info->cpu[i].address;
648                 pcpu->state = (cpu >= info->configured) ?
649                         CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
650                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
651                 set_cpu_present(cpu, true);
652                 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
653                         set_cpu_present(cpu, false);
654                 else
655                         nr++;
656                 cpu = cpumask_next(cpu, &avail);
657         }
658         return nr;
659 }
660
661 static void __init smp_detect_cpus(void)
662 {
663         unsigned int cpu, c_cpus, s_cpus;
664         struct sclp_cpu_info *info;
665
666         info = smp_get_cpu_info();
667         if (!info)
668                 panic("smp_detect_cpus failed to allocate memory\n");
669         if (info->has_cpu_type) {
670                 for (cpu = 0; cpu < info->combined; cpu++) {
671                         if (info->cpu[cpu].address != boot_cpu_address)
672                                 continue;
673                         /* The boot cpu dictates the cpu type. */
674                         boot_cpu_type = info->cpu[cpu].type;
675                         break;
676                 }
677         }
678         c_cpus = s_cpus = 0;
679         for (cpu = 0; cpu < info->combined; cpu++) {
680                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
681                         continue;
682                 if (cpu < info->configured) {
683                         smp_get_save_area(c_cpus, info->cpu[cpu].address);
684                         c_cpus++;
685                 } else
686                         s_cpus++;
687         }
688         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
689         get_online_cpus();
690         __smp_rescan_cpus(info, 0);
691         put_online_cpus();
692         kfree(info);
693 }
694
695 /*
696  *      Activate a secondary processor.
697  */
698 static void __cpuinit smp_start_secondary(void *cpuvoid)
699 {
700         S390_lowcore.last_update_clock = get_clock();
701         S390_lowcore.restart_stack = (unsigned long) restart_stack;
702         S390_lowcore.restart_fn = (unsigned long) do_restart;
703         S390_lowcore.restart_data = 0;
704         S390_lowcore.restart_source = -1UL;
705         restore_access_regs(S390_lowcore.access_regs_save_area);
706         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
707         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
708         cpu_init();
709         preempt_disable();
710         init_cpu_timer();
711         init_cpu_vtimer();
712         pfault_init();
713         notify_cpu_starting(smp_processor_id());
714         ipi_call_lock();
715         set_cpu_online(smp_processor_id(), true);
716         ipi_call_unlock();
717         local_irq_enable();
718         /* cpu_idle will call schedule for us */
719         cpu_idle();
720 }
721
722 struct create_idle {
723         struct work_struct work;
724         struct task_struct *idle;
725         struct completion done;
726         int cpu;
727 };
728
729 static void __cpuinit smp_fork_idle(struct work_struct *work)
730 {
731         struct create_idle *c_idle;
732
733         c_idle = container_of(work, struct create_idle, work);
734         c_idle->idle = fork_idle(c_idle->cpu);
735         complete(&c_idle->done);
736 }
737
738 /* Upping and downing of CPUs */
739 int __cpuinit __cpu_up(unsigned int cpu)
740 {
741         struct create_idle c_idle;
742         struct pcpu *pcpu;
743         int rc;
744
745         pcpu = pcpu_devices + cpu;
746         if (pcpu->state != CPU_STATE_CONFIGURED)
747                 return -EIO;
748         if (pcpu_sigp_retry(pcpu, sigp_initial_cpu_reset, 0) !=
749             sigp_order_code_accepted)
750                 return -EIO;
751         if (!pcpu->idle) {
752                 c_idle.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done);
753                 INIT_WORK_ONSTACK(&c_idle.work, smp_fork_idle);
754                 c_idle.cpu = cpu;
755                 schedule_work(&c_idle.work);
756                 wait_for_completion(&c_idle.done);
757                 if (IS_ERR(c_idle.idle))
758                         return PTR_ERR(c_idle.idle);
759                 pcpu->idle = c_idle.idle;
760         }
761         init_idle(pcpu->idle, cpu);
762         rc = pcpu_alloc_lowcore(pcpu, cpu);
763         if (rc)
764                 return rc;
765         pcpu_prepare_secondary(pcpu, cpu);
766         pcpu_attach_task(pcpu, pcpu->idle);
767         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
768         while (!cpu_online(cpu))
769                 cpu_relax();
770         return 0;
771 }
772
773 static int __init setup_possible_cpus(char *s)
774 {
775         int max, cpu;
776
777         if (kstrtoint(s, 0, &max) < 0)
778                 return 0;
779         init_cpu_possible(cpumask_of(0));
780         for (cpu = 1; cpu < max && cpu < nr_cpu_ids; cpu++)
781                 set_cpu_possible(cpu, true);
782         return 0;
783 }
784 early_param("possible_cpus", setup_possible_cpus);
785
786 #ifdef CONFIG_HOTPLUG_CPU
787
788 int __cpu_disable(void)
789 {
790         unsigned long cregs[16];
791
792         set_cpu_online(smp_processor_id(), false);
793         /* Disable pseudo page faults on this cpu. */
794         pfault_fini();
795         /* Disable interrupt sources via control register. */
796         __ctl_store(cregs, 0, 15);
797         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
798         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
799         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
800         __ctl_load(cregs, 0, 15);
801         return 0;
802 }
803
804 void __cpu_die(unsigned int cpu)
805 {
806         struct pcpu *pcpu;
807
808         /* Wait until target cpu is down */
809         pcpu = pcpu_devices + cpu;
810         while (!pcpu_stopped(pcpu))
811                 cpu_relax();
812         pcpu_free_lowcore(pcpu);
813         atomic_dec(&init_mm.context.attach_count);
814 }
815
816 void __noreturn cpu_die(void)
817 {
818         idle_task_exit();
819         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), sigp_stop, 0);
820         for (;;) ;
821 }
822
823 #endif /* CONFIG_HOTPLUG_CPU */
824
825 static void smp_call_os_info_init_fn(void)
826 {
827         int (*init_fn)(void);
828         unsigned long size;
829
830         init_fn = os_info_old_entry(OS_INFO_INIT_FN, &size);
831         if (!init_fn)
832                 return;
833         init_fn();
834 }
835
836 void __init smp_prepare_cpus(unsigned int max_cpus)
837 {
838         /* request the 0x1201 emergency signal external interrupt */
839         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
840                 panic("Couldn't request external interrupt 0x1201");
841         /* request the 0x1202 external call external interrupt */
842         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
843                 panic("Couldn't request external interrupt 0x1202");
844         smp_call_os_info_init_fn();
845         smp_detect_cpus();
846 }
847
848 void __init smp_prepare_boot_cpu(void)
849 {
850         struct pcpu *pcpu = pcpu_devices;
851
852         boot_cpu_address = stap();
853         pcpu->idle = current;
854         pcpu->state = CPU_STATE_CONFIGURED;
855         pcpu->address = boot_cpu_address;
856         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
857         pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE;
858         pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE;
859         S390_lowcore.percpu_offset = __per_cpu_offset[0];
860         cpu_set_polarization(0, POLARIZATION_UNKNOWN);
861         set_cpu_present(0, true);
862         set_cpu_online(0, true);
863 }
864
865 void __init smp_cpus_done(unsigned int max_cpus)
866 {
867 }
868
869 void __init smp_setup_processor_id(void)
870 {
871         S390_lowcore.cpu_nr = 0;
872 }
873
874 /*
875  * the frequency of the profiling timer can be changed
876  * by writing a multiplier value into /proc/profile.
877  *
878  * usually you want to run this on all CPUs ;)
879  */
880 int setup_profiling_timer(unsigned int multiplier)
881 {
882         return 0;
883 }
884
885 #ifdef CONFIG_HOTPLUG_CPU
886 static ssize_t cpu_configure_show(struct device *dev,
887                                   struct device_attribute *attr, char *buf)
888 {
889         ssize_t count;
890
891         mutex_lock(&smp_cpu_state_mutex);
892         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
893         mutex_unlock(&smp_cpu_state_mutex);
894         return count;
895 }
896
897 static ssize_t cpu_configure_store(struct device *dev,
898                                    struct device_attribute *attr,
899                                    const char *buf, size_t count)
900 {
901         struct pcpu *pcpu;
902         int cpu, val, rc;
903         char delim;
904
905         if (sscanf(buf, "%d %c", &val, &delim) != 1)
906                 return -EINVAL;
907         if (val != 0 && val != 1)
908                 return -EINVAL;
909         get_online_cpus();
910         mutex_lock(&smp_cpu_state_mutex);
911         rc = -EBUSY;
912         /* disallow configuration changes of online cpus and cpu 0 */
913         cpu = dev->id;
914         if (cpu_online(cpu) || cpu == 0)
915                 goto out;
916         pcpu = pcpu_devices + cpu;
917         rc = 0;
918         switch (val) {
919         case 0:
920                 if (pcpu->state != CPU_STATE_CONFIGURED)
921                         break;
922                 rc = sclp_cpu_deconfigure(pcpu->address);
923                 if (rc)
924                         break;
925                 pcpu->state = CPU_STATE_STANDBY;
926                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
927                 topology_expect_change();
928                 break;
929         case 1:
930                 if (pcpu->state != CPU_STATE_STANDBY)
931                         break;
932                 rc = sclp_cpu_configure(pcpu->address);
933                 if (rc)
934                         break;
935                 pcpu->state = CPU_STATE_CONFIGURED;
936                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
937                 topology_expect_change();
938                 break;
939         default:
940                 break;
941         }
942 out:
943         mutex_unlock(&smp_cpu_state_mutex);
944         put_online_cpus();
945         return rc ? rc : count;
946 }
947 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
948 #endif /* CONFIG_HOTPLUG_CPU */
949
950 static ssize_t show_cpu_address(struct device *dev,
951                                 struct device_attribute *attr, char *buf)
952 {
953         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
954 }
955 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
956
957 static struct attribute *cpu_common_attrs[] = {
958 #ifdef CONFIG_HOTPLUG_CPU
959         &dev_attr_configure.attr,
960 #endif
961         &dev_attr_address.attr,
962         NULL,
963 };
964
965 static struct attribute_group cpu_common_attr_group = {
966         .attrs = cpu_common_attrs,
967 };
968
969 static ssize_t show_capability(struct device *dev,
970                                 struct device_attribute *attr, char *buf)
971 {
972         unsigned int capability;
973         int rc;
974
975         rc = get_cpu_capability(&capability);
976         if (rc)
977                 return rc;
978         return sprintf(buf, "%u\n", capability);
979 }
980 static DEVICE_ATTR(capability, 0444, show_capability, NULL);
981
982 static ssize_t show_idle_count(struct device *dev,
983                                 struct device_attribute *attr, char *buf)
984 {
985         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
986         unsigned long long idle_count;
987         unsigned int sequence;
988
989         do {
990                 sequence = ACCESS_ONCE(idle->sequence);
991                 idle_count = ACCESS_ONCE(idle->idle_count);
992                 if (ACCESS_ONCE(idle->idle_enter))
993                         idle_count++;
994         } while ((sequence & 1) || (idle->sequence != sequence));
995         return sprintf(buf, "%llu\n", idle_count);
996 }
997 static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
998
999 static ssize_t show_idle_time(struct device *dev,
1000                                 struct device_attribute *attr, char *buf)
1001 {
1002         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
1003         unsigned long long now, idle_time, idle_enter, idle_exit;
1004         unsigned int sequence;
1005
1006         do {
1007                 now = get_clock();
1008                 sequence = ACCESS_ONCE(idle->sequence);
1009                 idle_time = ACCESS_ONCE(idle->idle_time);
1010                 idle_enter = ACCESS_ONCE(idle->idle_enter);
1011                 idle_exit = ACCESS_ONCE(idle->idle_exit);
1012         } while ((sequence & 1) || (idle->sequence != sequence));
1013         idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
1014         return sprintf(buf, "%llu\n", idle_time >> 12);
1015 }
1016 static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
1017
1018 static struct attribute *cpu_online_attrs[] = {
1019         &dev_attr_capability.attr,
1020         &dev_attr_idle_count.attr,
1021         &dev_attr_idle_time_us.attr,
1022         NULL,
1023 };
1024
1025 static struct attribute_group cpu_online_attr_group = {
1026         .attrs = cpu_online_attrs,
1027 };
1028
1029 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
1030                                     unsigned long action, void *hcpu)
1031 {
1032         unsigned int cpu = (unsigned int)(long)hcpu;
1033         struct cpu *c = &pcpu_devices[cpu].cpu;
1034         struct device *s = &c->dev;
1035         struct s390_idle_data *idle;
1036         int err = 0;
1037
1038         switch (action) {
1039         case CPU_ONLINE:
1040         case CPU_ONLINE_FROZEN:
1041                 idle = &per_cpu(s390_idle, cpu);
1042                 memset(idle, 0, sizeof(struct s390_idle_data));
1043                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1044                 break;
1045         case CPU_DEAD:
1046         case CPU_DEAD_FROZEN:
1047                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1048                 break;
1049         }
1050         return notifier_from_errno(err);
1051 }
1052
1053 static struct notifier_block __cpuinitdata smp_cpu_nb = {
1054         .notifier_call = smp_cpu_notify,
1055 };
1056
1057 static int __devinit smp_add_present_cpu(int cpu)
1058 {
1059         struct cpu *c = &pcpu_devices[cpu].cpu;
1060         struct device *s = &c->dev;
1061         int rc;
1062
1063         c->hotpluggable = 1;
1064         rc = register_cpu(c, cpu);
1065         if (rc)
1066                 goto out;
1067         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1068         if (rc)
1069                 goto out_cpu;
1070         if (cpu_online(cpu)) {
1071                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1072                 if (rc)
1073                         goto out_online;
1074         }
1075         rc = topology_cpu_init(c);
1076         if (rc)
1077                 goto out_topology;
1078         return 0;
1079
1080 out_topology:
1081         if (cpu_online(cpu))
1082                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1083 out_online:
1084         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1085 out_cpu:
1086 #ifdef CONFIG_HOTPLUG_CPU
1087         unregister_cpu(c);
1088 #endif
1089 out:
1090         return rc;
1091 }
1092
1093 #ifdef CONFIG_HOTPLUG_CPU
1094
1095 int __ref smp_rescan_cpus(void)
1096 {
1097         struct sclp_cpu_info *info;
1098         int nr;
1099
1100         info = smp_get_cpu_info();
1101         if (!info)
1102                 return -ENOMEM;
1103         get_online_cpus();
1104         mutex_lock(&smp_cpu_state_mutex);
1105         nr = __smp_rescan_cpus(info, 1);
1106         mutex_unlock(&smp_cpu_state_mutex);
1107         put_online_cpus();
1108         kfree(info);
1109         if (nr)
1110                 topology_schedule_update();
1111         return 0;
1112 }
1113
1114 static ssize_t __ref rescan_store(struct device *dev,
1115                                   struct device_attribute *attr,
1116                                   const char *buf,
1117                                   size_t count)
1118 {
1119         int rc;
1120
1121         rc = smp_rescan_cpus();
1122         return rc ? rc : count;
1123 }
1124 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1125 #endif /* CONFIG_HOTPLUG_CPU */
1126
1127 static int __init s390_smp_init(void)
1128 {
1129         int cpu, rc;
1130
1131         register_cpu_notifier(&smp_cpu_nb);
1132 #ifdef CONFIG_HOTPLUG_CPU
1133         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1134         if (rc)
1135                 return rc;
1136 #endif
1137         for_each_present_cpu(cpu) {
1138                 rc = smp_add_present_cpu(cpu);
1139                 if (rc)
1140                         return rc;
1141         }
1142         return 0;
1143 }
1144 subsys_initcall(s390_smp_init);