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TOMOYO Linux Cross Reference
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 "entry.h"
 49 
 50 enum {
 51         ec_schedule = 0,
 52         ec_call_function,
 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(u16 addr, u8 order, u32 parm, u32 *status)
 87 {
 88         register unsigned int reg1 asm ("1") = parm;
 89         int cc;
 90 
 91         asm volatile(
 92                 "       sigp    %1,%2,0(%3)\n"
 93                 "       ipm     %0\n"
 94                 "       srl     %0,28\n"
 95                 : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
 96         if (status && cc == 1)
 97                 *status = reg1;
 98         return cc;
 99 }
100 
101 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
102 {
103         int cc;
104 
105         while (1) {
106                 cc = __pcpu_sigp(addr, order, parm, NULL);
107                 if (cc != SIGP_CC_BUSY)
108                         return cc;
109                 cpu_relax();
110         }
111 }
112 
113 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
114 {
115         int cc, retry;
116 
117         for (retry = 0; ; retry++) {
118                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
119                 if (cc != SIGP_CC_BUSY)
120                         break;
121                 if (retry >= 3)
122                         udelay(10);
123         }
124         return cc;
125 }
126 
127 static inline int pcpu_stopped(struct pcpu *pcpu)
128 {
129         u32 uninitialized_var(status);
130 
131         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
132                         0, &status) != SIGP_CC_STATUS_STORED)
133                 return 0;
134         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
135 }
136 
137 static inline int pcpu_running(struct pcpu *pcpu)
138 {
139         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
140                         0, NULL) != SIGP_CC_STATUS_STORED)
141                 return 1;
142         /* Status stored condition code is equivalent to cpu not running. */
143         return 0;
144 }
145 
146 /*
147  * Find struct pcpu by cpu address.
148  */
149 static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
150 {
151         int cpu;
152 
153         for_each_cpu(cpu, mask)
154                 if (pcpu_devices[cpu].address == address)
155                         return pcpu_devices + cpu;
156         return NULL;
157 }
158 
159 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
160 {
161         int order;
162 
163         set_bit(ec_bit, &pcpu->ec_mask);
164         order = pcpu_running(pcpu) ?
165                 SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
166         pcpu_sigp_retry(pcpu, order, 0);
167 }
168 
169 static int __cpuinit pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
170 {
171         struct _lowcore *lc;
172 
173         if (pcpu != &pcpu_devices[0]) {
174                 pcpu->lowcore = (struct _lowcore *)
175                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
176                 pcpu->async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
177                 pcpu->panic_stack = __get_free_page(GFP_KERNEL);
178                 if (!pcpu->lowcore || !pcpu->panic_stack || !pcpu->async_stack)
179                         goto out;
180         }
181         lc = pcpu->lowcore;
182         memcpy(lc, &S390_lowcore, 512);
183         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
184         lc->async_stack = pcpu->async_stack + ASYNC_SIZE
185                 - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
186         lc->panic_stack = pcpu->panic_stack + PAGE_SIZE
187                 - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
188         lc->cpu_nr = cpu;
189 #ifndef CONFIG_64BIT
190         if (MACHINE_HAS_IEEE) {
191                 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
192                 if (!lc->extended_save_area_addr)
193                         goto out;
194         }
195 #else
196         if (vdso_alloc_per_cpu(lc))
197                 goto out;
198 #endif
199         lowcore_ptr[cpu] = lc;
200         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
201         return 0;
202 out:
203         if (pcpu != &pcpu_devices[0]) {
204                 free_page(pcpu->panic_stack);
205                 free_pages(pcpu->async_stack, ASYNC_ORDER);
206                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
207         }
208         return -ENOMEM;
209 }
210 
211 #ifdef CONFIG_HOTPLUG_CPU
212 
213 static void pcpu_free_lowcore(struct pcpu *pcpu)
214 {
215         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
216         lowcore_ptr[pcpu - pcpu_devices] = NULL;
217 #ifndef CONFIG_64BIT
218         if (MACHINE_HAS_IEEE) {
219                 struct _lowcore *lc = pcpu->lowcore;
220 
221                 free_page((unsigned long) lc->extended_save_area_addr);
222                 lc->extended_save_area_addr = 0;
223         }
224 #else
225         vdso_free_per_cpu(pcpu->lowcore);
226 #endif
227         if (pcpu != &pcpu_devices[0]) {
228                 free_page(pcpu->panic_stack);
229                 free_pages(pcpu->async_stack, ASYNC_ORDER);
230                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
231         }
232 }
233 
234 #endif /* CONFIG_HOTPLUG_CPU */
235 
236 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
237 {
238         struct _lowcore *lc = pcpu->lowcore;
239 
240         atomic_inc(&init_mm.context.attach_count);
241         lc->cpu_nr = cpu;
242         lc->percpu_offset = __per_cpu_offset[cpu];
243         lc->kernel_asce = S390_lowcore.kernel_asce;
244         lc->machine_flags = S390_lowcore.machine_flags;
245         lc->ftrace_func = S390_lowcore.ftrace_func;
246         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
247         __ctl_store(lc->cregs_save_area, 0, 15);
248         save_access_regs((unsigned int *) lc->access_regs_save_area);
249         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
250                MAX_FACILITY_BIT/8);
251 }
252 
253 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
254 {
255         struct _lowcore *lc = pcpu->lowcore;
256         struct thread_info *ti = task_thread_info(tsk);
257 
258         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
259                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
260         lc->thread_info = (unsigned long) task_thread_info(tsk);
261         lc->current_task = (unsigned long) tsk;
262         lc->user_timer = ti->user_timer;
263         lc->system_timer = ti->system_timer;
264         lc->steal_timer = 0;
265 }
266 
267 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
268 {
269         struct _lowcore *lc = pcpu->lowcore;
270 
271         lc->restart_stack = lc->kernel_stack;
272         lc->restart_fn = (unsigned long) func;
273         lc->restart_data = (unsigned long) data;
274         lc->restart_source = -1UL;
275         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
276 }
277 
278 /*
279  * Call function via PSW restart on pcpu and stop the current cpu.
280  */
281 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
282                           void *data, unsigned long stack)
283 {
284         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
285         unsigned long source_cpu = stap();
286 
287         __load_psw_mask(psw_kernel_bits);
288         if (pcpu->address == source_cpu)
289                 func(data);     /* should not return */
290         /* Stop target cpu (if func returns this stops the current cpu). */
291         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
292         /* Restart func on the target cpu and stop the current cpu. */
293         mem_assign_absolute(lc->restart_stack, stack);
294         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
295         mem_assign_absolute(lc->restart_data, (unsigned long) data);
296         mem_assign_absolute(lc->restart_source, source_cpu);
297         asm volatile(
298                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
299                 "       brc     2,0b    # busy, try again\n"
300                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
301                 "       brc     2,1b    # busy, try again\n"
302                 : : "d" (pcpu->address), "d" (source_cpu),
303                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
304                 : "", "1", "cc");
305         for (;;) ;
306 }
307 
308 /*
309  * Call function on an online CPU.
310  */
311 void smp_call_online_cpu(void (*func)(void *), void *data)
312 {
313         struct pcpu *pcpu;
314 
315         /* Use the current cpu if it is online. */
316         pcpu = pcpu_find_address(cpu_online_mask, stap());
317         if (!pcpu)
318                 /* Use the first online cpu. */
319                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
320         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
321 }
322 
323 /*
324  * Call function on the ipl CPU.
325  */
326 void smp_call_ipl_cpu(void (*func)(void *), void *data)
327 {
328         pcpu_delegate(&pcpu_devices[0], func, data,
329                       pcpu_devices->panic_stack + PAGE_SIZE);
330 }
331 
332 int smp_find_processor_id(u16 address)
333 {
334         int cpu;
335 
336         for_each_present_cpu(cpu)
337                 if (pcpu_devices[cpu].address == address)
338                         return cpu;
339         return -1;
340 }
341 
342 int smp_vcpu_scheduled(int cpu)
343 {
344         return pcpu_running(pcpu_devices + cpu);
345 }
346 
347 void smp_yield(void)
348 {
349         if (MACHINE_HAS_DIAG44)
350                 asm volatile("diag 0,0,0x44");
351 }
352 
353 void smp_yield_cpu(int cpu)
354 {
355         if (MACHINE_HAS_DIAG9C)
356                 asm volatile("diag %0,0,0x9c"
357                              : : "d" (pcpu_devices[cpu].address));
358         else if (MACHINE_HAS_DIAG44)
359                 asm volatile("diag 0,0,0x44");
360 }
361 
362 /*
363  * Send cpus emergency shutdown signal. This gives the cpus the
364  * opportunity to complete outstanding interrupts.
365  */
366 void smp_emergency_stop(cpumask_t *cpumask)
367 {
368         u64 end;
369         int cpu;
370 
371         end = get_tod_clock() + (1000000UL << 12);
372         for_each_cpu(cpu, cpumask) {
373                 struct pcpu *pcpu = pcpu_devices + cpu;
374                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
375                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
376                                    0, NULL) == SIGP_CC_BUSY &&
377                        get_tod_clock() < end)
378                         cpu_relax();
379         }
380         while (get_tod_clock() < end) {
381                 for_each_cpu(cpu, cpumask)
382                         if (pcpu_stopped(pcpu_devices + cpu))
383                                 cpumask_clear_cpu(cpu, cpumask);
384                 if (cpumask_empty(cpumask))
385                         break;
386                 cpu_relax();
387         }
388 }
389 
390 /*
391  * Stop all cpus but the current one.
392  */
393 void smp_send_stop(void)
394 {
395         cpumask_t cpumask;
396         int cpu;
397 
398         /* Disable all interrupts/machine checks */
399         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
400         trace_hardirqs_off();
401 
402         debug_set_critical();
403         cpumask_copy(&cpumask, cpu_online_mask);
404         cpumask_clear_cpu(smp_processor_id(), &cpumask);
405 
406         if (oops_in_progress)
407                 smp_emergency_stop(&cpumask);
408 
409         /* stop all processors */
410         for_each_cpu(cpu, &cpumask) {
411                 struct pcpu *pcpu = pcpu_devices + cpu;
412                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
413                 while (!pcpu_stopped(pcpu))
414                         cpu_relax();
415         }
416 }
417 
418 /*
419  * Stop the current cpu.
420  */
421 void smp_stop_cpu(void)
422 {
423         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
424         for (;;) ;
425 }
426 
427 /*
428  * This is the main routine where commands issued by other
429  * cpus are handled.
430  */
431 static void smp_handle_ext_call(void)
432 {
433         unsigned long bits;
434 
435         /* handle bit signal external calls */
436         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
437         if (test_bit(ec_stop_cpu, &bits))
438                 smp_stop_cpu();
439         if (test_bit(ec_schedule, &bits))
440                 scheduler_ipi();
441         if (test_bit(ec_call_function, &bits))
442                 generic_smp_call_function_interrupt();
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);
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 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
540 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
541 
542 static void __init smp_get_save_area(int cpu, u16 address)
543 {
544         void *lc = pcpu_devices[0].lowcore;
545         struct save_area *save_area;
546 
547         if (is_kdump_kernel())
548                 return;
549         if (!OLDMEM_BASE && (address == boot_cpu_address ||
550                              ipl_info.type != IPL_TYPE_FCP_DUMP))
551                 return;
552         if (cpu >= NR_CPUS) {
553                 pr_warning("CPU %i exceeds the maximum %i and is excluded "
554                            "from the dump\n", cpu, NR_CPUS - 1);
555                 return;
556         }
557         save_area = kmalloc(sizeof(struct save_area), GFP_KERNEL);
558         if (!save_area)
559                 panic("could not allocate memory for save area\n");
560         zfcpdump_save_areas[cpu] = save_area;
561 #ifdef CONFIG_CRASH_DUMP
562         if (address == boot_cpu_address) {
563                 /* Copy the registers of the boot cpu. */
564                 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
565                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
566                 return;
567         }
568 #endif
569         /* Get the registers of a non-boot cpu. */
570         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
571         memcpy_real(save_area, lc + SAVE_AREA_BASE, sizeof(*save_area));
572 }
573 
574 int smp_store_status(int cpu)
575 {
576         struct pcpu *pcpu;
577 
578         pcpu = pcpu_devices + cpu;
579         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
580                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
581                 return -EIO;
582         return 0;
583 }
584 
585 #else /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
586 
587 static inline void smp_get_save_area(int cpu, u16 address) { }
588 
589 #endif /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
590 
591 void smp_cpu_set_polarization(int cpu, int val)
592 {
593         pcpu_devices[cpu].polarization = val;
594 }
595 
596 int smp_cpu_get_polarization(int cpu)
597 {
598         return pcpu_devices[cpu].polarization;
599 }
600 
601 static struct sclp_cpu_info *smp_get_cpu_info(void)
602 {
603         static int use_sigp_detection;
604         struct sclp_cpu_info *info;
605         int address;
606 
607         info = kzalloc(sizeof(*info), GFP_KERNEL);
608         if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
609                 use_sigp_detection = 1;
610                 for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
611                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
612                             SIGP_CC_NOT_OPERATIONAL)
613                                 continue;
614                         info->cpu[info->configured].address = address;
615                         info->configured++;
616                 }
617                 info->combined = info->configured;
618         }
619         return info;
620 }
621 
622 static int __cpuinit smp_add_present_cpu(int cpu);
623 
624 static int __cpuinit __smp_rescan_cpus(struct sclp_cpu_info *info,
625                                        int sysfs_add)
626 {
627         struct pcpu *pcpu;
628         cpumask_t avail;
629         int cpu, nr, i;
630 
631         nr = 0;
632         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
633         cpu = cpumask_first(&avail);
634         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
635                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
636                         continue;
637                 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
638                         continue;
639                 pcpu = pcpu_devices + cpu;
640                 pcpu->address = info->cpu[i].address;
641                 pcpu->state = (i >= info->configured) ?
642                         CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
643                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
644                 set_cpu_present(cpu, true);
645                 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
646                         set_cpu_present(cpu, false);
647                 else
648                         nr++;
649                 cpu = cpumask_next(cpu, &avail);
650         }
651         return nr;
652 }
653 
654 static void __init smp_detect_cpus(void)
655 {
656         unsigned int cpu, c_cpus, s_cpus;
657         struct sclp_cpu_info *info;
658 
659         info = smp_get_cpu_info();
660         if (!info)
661                 panic("smp_detect_cpus failed to allocate memory\n");
662         if (info->has_cpu_type) {
663                 for (cpu = 0; cpu < info->combined; cpu++) {
664                         if (info->cpu[cpu].address != boot_cpu_address)
665                                 continue;
666                         /* The boot cpu dictates the cpu type. */
667                         boot_cpu_type = info->cpu[cpu].type;
668                         break;
669                 }
670         }
671         c_cpus = s_cpus = 0;
672         for (cpu = 0; cpu < info->combined; cpu++) {
673                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
674                         continue;
675                 if (cpu < info->configured) {
676                         smp_get_save_area(c_cpus, info->cpu[cpu].address);
677                         c_cpus++;
678                 } else
679                         s_cpus++;
680         }
681         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
682         get_online_cpus();
683         __smp_rescan_cpus(info, 0);
684         put_online_cpus();
685         kfree(info);
686 }
687 
688 /*
689  *      Activate a secondary processor.
690  */
691 static void __cpuinit smp_start_secondary(void *cpuvoid)
692 {
693         S390_lowcore.last_update_clock = get_tod_clock();
694         S390_lowcore.restart_stack = (unsigned long) restart_stack;
695         S390_lowcore.restart_fn = (unsigned long) do_restart;
696         S390_lowcore.restart_data = 0;
697         S390_lowcore.restart_source = -1UL;
698         restore_access_regs(S390_lowcore.access_regs_save_area);
699         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
700         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
701         cpu_init();
702         preempt_disable();
703         init_cpu_timer();
704         init_cpu_vtimer();
705         pfault_init();
706         notify_cpu_starting(smp_processor_id());
707         set_cpu_online(smp_processor_id(), true);
708         inc_irq_stat(CPU_RST);
709         local_irq_enable();
710         cpu_startup_entry(CPUHP_ONLINE);
711 }
712 
713 /* Upping and downing of CPUs */
714 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
715 {
716         struct pcpu *pcpu;
717         int rc;
718 
719         pcpu = pcpu_devices + cpu;
720         if (pcpu->state != CPU_STATE_CONFIGURED)
721                 return -EIO;
722         if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
723             SIGP_CC_ORDER_CODE_ACCEPTED)
724                 return -EIO;
725 
726         rc = pcpu_alloc_lowcore(pcpu, cpu);
727         if (rc)
728                 return rc;
729         pcpu_prepare_secondary(pcpu, cpu);
730         pcpu_attach_task(pcpu, tidle);
731         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
732         while (!cpu_online(cpu))
733                 cpu_relax();
734         return 0;
735 }
736 
737 static int __init setup_possible_cpus(char *s)
738 {
739         int max, cpu;
740 
741         if (kstrtoint(s, 0, &max) < 0)
742                 return 0;
743         init_cpu_possible(cpumask_of(0));
744         for (cpu = 1; cpu < max && cpu < nr_cpu_ids; cpu++)
745                 set_cpu_possible(cpu, true);
746         return 0;
747 }
748 early_param("possible_cpus", setup_possible_cpus);
749 
750 #ifdef CONFIG_HOTPLUG_CPU
751 
752 int __cpu_disable(void)
753 {
754         unsigned long cregs[16];
755 
756         /* Handle possible pending IPIs */
757         smp_handle_ext_call();
758         set_cpu_online(smp_processor_id(), false);
759         /* Disable pseudo page faults on this cpu. */
760         pfault_fini();
761         /* Disable interrupt sources via control register. */
762         __ctl_store(cregs, 0, 15);
763         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
764         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
765         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
766         __ctl_load(cregs, 0, 15);
767         return 0;
768 }
769 
770 void __cpu_die(unsigned int cpu)
771 {
772         struct pcpu *pcpu;
773 
774         /* Wait until target cpu is down */
775         pcpu = pcpu_devices + cpu;
776         while (!pcpu_stopped(pcpu))
777                 cpu_relax();
778         pcpu_free_lowcore(pcpu);
779         atomic_dec(&init_mm.context.attach_count);
780 }
781 
782 void __noreturn cpu_die(void)
783 {
784         idle_task_exit();
785         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
786         for (;;) ;
787 }
788 
789 #endif /* CONFIG_HOTPLUG_CPU */
790 
791 void __init smp_prepare_cpus(unsigned int max_cpus)
792 {
793         /* request the 0x1201 emergency signal external interrupt */
794         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
795                 panic("Couldn't request external interrupt 0x1201");
796         /* request the 0x1202 external call external interrupt */
797         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
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 __cpuinit smp_cpu_notify(struct notifier_block *self,
971                                     unsigned long action, 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 __cpuinit smp_add_present_cpu(int cpu)
990 {
991         struct cpu *c = &pcpu_devices[cpu].cpu;
992         struct device *s = &c->dev;
993         int rc;
994 
995         c->hotpluggable = 1;
996         rc = register_cpu(c, cpu);
997         if (rc)
998                 goto out;
999         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1000         if (rc)
1001                 goto out_cpu;
1002         if (cpu_online(cpu)) {
1003                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1004                 if (rc)
1005                         goto out_online;
1006         }
1007         rc = topology_cpu_init(c);
1008         if (rc)
1009                 goto out_topology;
1010         return 0;
1011 
1012 out_topology:
1013         if (cpu_online(cpu))
1014                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1015 out_online:
1016         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1017 out_cpu:
1018 #ifdef CONFIG_HOTPLUG_CPU
1019         unregister_cpu(c);
1020 #endif
1021 out:
1022         return rc;
1023 }
1024 
1025 #ifdef CONFIG_HOTPLUG_CPU
1026 
1027 int __ref smp_rescan_cpus(void)
1028 {
1029         struct sclp_cpu_info *info;
1030         int nr;
1031 
1032         info = smp_get_cpu_info();
1033         if (!info)
1034                 return -ENOMEM;
1035         get_online_cpus();
1036         mutex_lock(&smp_cpu_state_mutex);
1037         nr = __smp_rescan_cpus(info, 1);
1038         mutex_unlock(&smp_cpu_state_mutex);
1039         put_online_cpus();
1040         kfree(info);
1041         if (nr)
1042                 topology_schedule_update();
1043         return 0;
1044 }
1045 
1046 static ssize_t __ref rescan_store(struct device *dev,
1047                                   struct device_attribute *attr,
1048                                   const char *buf,
1049                                   size_t count)
1050 {
1051         int rc;
1052 
1053         rc = smp_rescan_cpus();
1054         return rc ? rc : count;
1055 }
1056 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1057 #endif /* CONFIG_HOTPLUG_CPU */
1058 
1059 static int __init s390_smp_init(void)
1060 {
1061         int cpu, rc;
1062 
1063         hotcpu_notifier(smp_cpu_notify, 0);
1064 #ifdef CONFIG_HOTPLUG_CPU
1065         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1066         if (rc)
1067                 return rc;
1068 #endif
1069         for_each_present_cpu(cpu) {
1070                 rc = smp_add_present_cpu(cpu);
1071                 if (rc)
1072                         return rc;
1073         }
1074         return 0;
1075 }
1076 subsys_initcall(s390_smp_init);
1077 

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