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Linux/arch/s390/kernel/smp.c

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

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