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