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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/bootmem.h>
 23 #include <linux/module.h>
 24 #include <linux/init.h>
 25 #include <linux/mm.h>
 26 #include <linux/err.h>
 27 #include <linux/spinlock.h>
 28 #include <linux/kernel_stat.h>
 29 #include <linux/delay.h>
 30 #include <linux/interrupt.h>
 31 #include <linux/irqflags.h>
 32 #include <linux/cpu.h>
 33 #include <linux/slab.h>
 34 #include <linux/crash_dump.h>
 35 #include <linux/memblock.h>
 36 #include <asm/asm-offsets.h>
 37 #include <asm/diag.h>
 38 #include <asm/switch_to.h>
 39 #include <asm/facility.h>
 40 #include <asm/ipl.h>
 41 #include <asm/setup.h>
 42 #include <asm/irq.h>
 43 #include <asm/tlbflush.h>
 44 #include <asm/vtimer.h>
 45 #include <asm/lowcore.h>
 46 #include <asm/sclp.h>
 47 #include <asm/vdso.h>
 48 #include <asm/debug.h>
 49 #include <asm/os_info.h>
 50 #include <asm/sigp.h>
 51 #include <asm/idle.h>
 52 #include "entry.h"
 53 
 54 enum {
 55         ec_schedule = 0,
 56         ec_call_function_single,
 57         ec_stop_cpu,
 58 };
 59 
 60 enum {
 61         CPU_STATE_STANDBY,
 62         CPU_STATE_CONFIGURED,
 63 };
 64 
 65 static DEFINE_PER_CPU(struct cpu *, cpu_device);
 66 
 67 struct pcpu {
 68         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
 69         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
 70         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
 71         signed char state;              /* physical cpu state */
 72         signed char polarization;       /* physical polarization */
 73         u16 address;                    /* physical cpu address */
 74 };
 75 
 76 static u8 boot_core_type;
 77 static struct pcpu pcpu_devices[NR_CPUS];
 78 
 79 unsigned int smp_cpu_mt_shift;
 80 EXPORT_SYMBOL(smp_cpu_mt_shift);
 81 
 82 unsigned int smp_cpu_mtid;
 83 EXPORT_SYMBOL(smp_cpu_mtid);
 84 
 85 #ifdef CONFIG_CRASH_DUMP
 86 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
 87 #endif
 88 
 89 static unsigned int smp_max_threads __initdata = -1U;
 90 
 91 static int __init early_nosmt(char *s)
 92 {
 93         smp_max_threads = 1;
 94         return 0;
 95 }
 96 early_param("nosmt", early_nosmt);
 97 
 98 static int __init early_smt(char *s)
 99 {
100         get_option(&s, &smp_max_threads);
101         return 0;
102 }
103 early_param("smt", early_smt);
104 
105 /*
106  * The smp_cpu_state_mutex must be held when changing the state or polarization
107  * member of a pcpu data structure within the pcpu_devices arreay.
108  */
109 DEFINE_MUTEX(smp_cpu_state_mutex);
110 
111 /*
112  * Signal processor helper functions.
113  */
114 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
115 {
116         int cc;
117 
118         while (1) {
119                 cc = __pcpu_sigp(addr, order, parm, NULL);
120                 if (cc != SIGP_CC_BUSY)
121                         return cc;
122                 cpu_relax();
123         }
124 }
125 
126 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
127 {
128         int cc, retry;
129 
130         for (retry = 0; ; retry++) {
131                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
132                 if (cc != SIGP_CC_BUSY)
133                         break;
134                 if (retry >= 3)
135                         udelay(10);
136         }
137         return cc;
138 }
139 
140 static inline int pcpu_stopped(struct pcpu *pcpu)
141 {
142         u32 uninitialized_var(status);
143 
144         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
145                         0, &status) != SIGP_CC_STATUS_STORED)
146                 return 0;
147         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
148 }
149 
150 static inline int pcpu_running(struct pcpu *pcpu)
151 {
152         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
153                         0, NULL) != SIGP_CC_STATUS_STORED)
154                 return 1;
155         /* Status stored condition code is equivalent to cpu not running. */
156         return 0;
157 }
158 
159 /*
160  * Find struct pcpu by cpu address.
161  */
162 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
163 {
164         int cpu;
165 
166         for_each_cpu(cpu, mask)
167                 if (pcpu_devices[cpu].address == address)
168                         return pcpu_devices + cpu;
169         return NULL;
170 }
171 
172 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
173 {
174         int order;
175 
176         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
177                 return;
178         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
179         pcpu->ec_clk = get_tod_clock_fast();
180         pcpu_sigp_retry(pcpu, order, 0);
181 }
182 
183 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
184 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
185 
186 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
187 {
188         unsigned long async_stack, panic_stack;
189         struct lowcore *lc;
190 
191         if (pcpu != &pcpu_devices[0]) {
192                 pcpu->lowcore = (struct lowcore *)
193                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
194                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
195                 panic_stack = __get_free_page(GFP_KERNEL);
196                 if (!pcpu->lowcore || !panic_stack || !async_stack)
197                         goto out;
198         } else {
199                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
200                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
201         }
202         lc = pcpu->lowcore;
203         memcpy(lc, &S390_lowcore, 512);
204         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
205         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
206         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
207         lc->cpu_nr = cpu;
208         lc->spinlock_lockval = arch_spin_lockval(cpu);
209         if (MACHINE_HAS_VX)
210                 lc->vector_save_area_addr =
211                         (unsigned long) &lc->vector_save_area;
212         if (vdso_alloc_per_cpu(lc))
213                 goto out;
214         lowcore_ptr[cpu] = lc;
215         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
216         return 0;
217 out:
218         if (pcpu != &pcpu_devices[0]) {
219                 free_page(panic_stack);
220                 free_pages(async_stack, ASYNC_ORDER);
221                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
222         }
223         return -ENOMEM;
224 }
225 
226 #ifdef CONFIG_HOTPLUG_CPU
227 
228 static void pcpu_free_lowcore(struct pcpu *pcpu)
229 {
230         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
231         lowcore_ptr[pcpu - pcpu_devices] = NULL;
232         vdso_free_per_cpu(pcpu->lowcore);
233         if (pcpu == &pcpu_devices[0])
234                 return;
235         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
236         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
237         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
238 }
239 
240 #endif /* CONFIG_HOTPLUG_CPU */
241 
242 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
243 {
244         struct lowcore *lc = pcpu->lowcore;
245 
246         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
247         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
248         lc->cpu_nr = cpu;
249         lc->spinlock_lockval = arch_spin_lockval(cpu);
250         lc->percpu_offset = __per_cpu_offset[cpu];
251         lc->kernel_asce = S390_lowcore.kernel_asce;
252         lc->machine_flags = S390_lowcore.machine_flags;
253         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
254         __ctl_store(lc->cregs_save_area, 0, 15);
255         save_access_regs((unsigned int *) lc->access_regs_save_area);
256         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
257                MAX_FACILITY_BIT/8);
258 }
259 
260 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
261 {
262         struct lowcore *lc = pcpu->lowcore;
263 
264         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
265                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
266         lc->current_task = (unsigned long) tsk;
267         lc->lpp = LPP_MAGIC;
268         lc->current_pid = tsk->pid;
269         lc->user_timer = tsk->thread.user_timer;
270         lc->system_timer = tsk->thread.system_timer;
271         lc->steal_timer = 0;
272 }
273 
274 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
275 {
276         struct lowcore *lc = pcpu->lowcore;
277 
278         lc->restart_stack = lc->kernel_stack;
279         lc->restart_fn = (unsigned long) func;
280         lc->restart_data = (unsigned long) data;
281         lc->restart_source = -1UL;
282         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
283 }
284 
285 /*
286  * Call function via PSW restart on pcpu and stop the current cpu.
287  */
288 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
289                           void *data, unsigned long stack)
290 {
291         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
292         unsigned long source_cpu = stap();
293 
294         __load_psw_mask(PSW_KERNEL_BITS);
295         if (pcpu->address == source_cpu)
296                 func(data);     /* should not return */
297         /* Stop target cpu (if func returns this stops the current cpu). */
298         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
299         /* Restart func on the target cpu and stop the current cpu. */
300         mem_assign_absolute(lc->restart_stack, stack);
301         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
302         mem_assign_absolute(lc->restart_data, (unsigned long) data);
303         mem_assign_absolute(lc->restart_source, source_cpu);
304         asm volatile(
305                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
306                 "       brc     2,0b    # busy, try again\n"
307                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
308                 "       brc     2,1b    # busy, try again\n"
309                 : : "d" (pcpu->address), "d" (source_cpu),
310                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
311                 : "", "1", "cc");
312         for (;;) ;
313 }
314 
315 /*
316  * Enable additional logical cpus for multi-threading.
317  */
318 static int pcpu_set_smt(unsigned int mtid)
319 {
320         int cc;
321 
322         if (smp_cpu_mtid == mtid)
323                 return 0;
324         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
325         if (cc == 0) {
326                 smp_cpu_mtid = mtid;
327                 smp_cpu_mt_shift = 0;
328                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
329                         smp_cpu_mt_shift++;
330                 pcpu_devices[0].address = stap();
331         }
332         return cc;
333 }
334 
335 /*
336  * Call function on an online CPU.
337  */
338 void smp_call_online_cpu(void (*func)(void *), void *data)
339 {
340         struct pcpu *pcpu;
341 
342         /* Use the current cpu if it is online. */
343         pcpu = pcpu_find_address(cpu_online_mask, stap());
344         if (!pcpu)
345                 /* Use the first online cpu. */
346                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
347         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
348 }
349 
350 /*
351  * Call function on the ipl CPU.
352  */
353 void smp_call_ipl_cpu(void (*func)(void *), void *data)
354 {
355         pcpu_delegate(&pcpu_devices[0], func, data,
356                       pcpu_devices->lowcore->panic_stack -
357                       PANIC_FRAME_OFFSET + PAGE_SIZE);
358 }
359 
360 int smp_find_processor_id(u16 address)
361 {
362         int cpu;
363 
364         for_each_present_cpu(cpu)
365                 if (pcpu_devices[cpu].address == address)
366                         return cpu;
367         return -1;
368 }
369 
370 bool arch_vcpu_is_preempted(int cpu)
371 {
372         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
373                 return false;
374         if (pcpu_running(pcpu_devices + cpu))
375                 return false;
376         return true;
377 }
378 EXPORT_SYMBOL(arch_vcpu_is_preempted);
379 
380 void smp_yield_cpu(int cpu)
381 {
382         if (MACHINE_HAS_DIAG9C) {
383                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
384                 asm volatile("diag %0,0,0x9c"
385                              : : "d" (pcpu_devices[cpu].address));
386         } else if (MACHINE_HAS_DIAG44) {
387                 diag_stat_inc_norecursion(DIAG_STAT_X044);
388                 asm volatile("diag 0,0,0x44");
389         }
390 }
391 
392 /*
393  * Send cpus emergency shutdown signal. This gives the cpus the
394  * opportunity to complete outstanding interrupts.
395  */
396 static void smp_emergency_stop(cpumask_t *cpumask)
397 {
398         u64 end;
399         int cpu;
400 
401         end = get_tod_clock() + (1000000UL << 12);
402         for_each_cpu(cpu, cpumask) {
403                 struct pcpu *pcpu = pcpu_devices + cpu;
404                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
405                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
406                                    0, NULL) == SIGP_CC_BUSY &&
407                        get_tod_clock() < end)
408                         cpu_relax();
409         }
410         while (get_tod_clock() < end) {
411                 for_each_cpu(cpu, cpumask)
412                         if (pcpu_stopped(pcpu_devices + cpu))
413                                 cpumask_clear_cpu(cpu, cpumask);
414                 if (cpumask_empty(cpumask))
415                         break;
416                 cpu_relax();
417         }
418 }
419 
420 /*
421  * Stop all cpus but the current one.
422  */
423 void smp_send_stop(void)
424 {
425         cpumask_t cpumask;
426         int cpu;
427 
428         /* Disable all interrupts/machine checks */
429         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
430         trace_hardirqs_off();
431 
432         debug_set_critical();
433         cpumask_copy(&cpumask, cpu_online_mask);
434         cpumask_clear_cpu(smp_processor_id(), &cpumask);
435 
436         if (oops_in_progress)
437                 smp_emergency_stop(&cpumask);
438 
439         /* stop all processors */
440         for_each_cpu(cpu, &cpumask) {
441                 struct pcpu *pcpu = pcpu_devices + cpu;
442                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
443                 while (!pcpu_stopped(pcpu))
444                         cpu_relax();
445         }
446 }
447 
448 /*
449  * This is the main routine where commands issued by other
450  * cpus are handled.
451  */
452 static void smp_handle_ext_call(void)
453 {
454         unsigned long bits;
455 
456         /* handle bit signal external calls */
457         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
458         if (test_bit(ec_stop_cpu, &bits))
459                 smp_stop_cpu();
460         if (test_bit(ec_schedule, &bits))
461                 scheduler_ipi();
462         if (test_bit(ec_call_function_single, &bits))
463                 generic_smp_call_function_single_interrupt();
464 }
465 
466 static void do_ext_call_interrupt(struct ext_code ext_code,
467                                   unsigned int param32, unsigned long param64)
468 {
469         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
470         smp_handle_ext_call();
471 }
472 
473 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
474 {
475         int cpu;
476 
477         for_each_cpu(cpu, mask)
478                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
479 }
480 
481 void arch_send_call_function_single_ipi(int cpu)
482 {
483         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
484 }
485 
486 /*
487  * this function sends a 'reschedule' IPI to another CPU.
488  * it goes straight through and wastes no time serializing
489  * anything. Worst case is that we lose a reschedule ...
490  */
491 void smp_send_reschedule(int cpu)
492 {
493         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
494 }
495 
496 /*
497  * parameter area for the set/clear control bit callbacks
498  */
499 struct ec_creg_mask_parms {
500         unsigned long orval;
501         unsigned long andval;
502         int cr;
503 };
504 
505 /*
506  * callback for setting/clearing control bits
507  */
508 static void smp_ctl_bit_callback(void *info)
509 {
510         struct ec_creg_mask_parms *pp = info;
511         unsigned long cregs[16];
512 
513         __ctl_store(cregs, 0, 15);
514         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
515         __ctl_load(cregs, 0, 15);
516 }
517 
518 /*
519  * Set a bit in a control register of all cpus
520  */
521 void smp_ctl_set_bit(int cr, int bit)
522 {
523         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
524 
525         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
526 }
527 EXPORT_SYMBOL(smp_ctl_set_bit);
528 
529 /*
530  * Clear a bit in a control register of all cpus
531  */
532 void smp_ctl_clear_bit(int cr, int bit)
533 {
534         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
535 
536         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
537 }
538 EXPORT_SYMBOL(smp_ctl_clear_bit);
539 
540 #ifdef CONFIG_CRASH_DUMP
541 
542 int smp_store_status(int cpu)
543 {
544         struct pcpu *pcpu = pcpu_devices + cpu;
545         unsigned long pa;
546 
547         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
548         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
549                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
550                 return -EIO;
551         if (!MACHINE_HAS_VX)
552                 return 0;
553         pa = __pa(pcpu->lowcore->vector_save_area_addr);
554         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
555                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
556                 return -EIO;
557         return 0;
558 }
559 
560 /*
561  * Collect CPU state of the previous, crashed system.
562  * There are four cases:
563  * 1) standard zfcp dump
564  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
565  *    The state for all CPUs except the boot CPU needs to be collected
566  *    with sigp stop-and-store-status. The boot CPU state is located in
567  *    the absolute lowcore of the memory stored in the HSA. The zcore code
568  *    will copy the boot CPU state from the HSA.
569  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
570  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
571  *    The state for all CPUs except the boot CPU needs to be collected
572  *    with sigp stop-and-store-status. The firmware or the boot-loader
573  *    stored the registers of the boot CPU in the absolute lowcore in the
574  *    memory of the old system.
575  * 3) kdump and the old kernel did not store the CPU state,
576  *    or stand-alone kdump for DASD
577  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
578  *    The state for all CPUs except the boot CPU needs to be collected
579  *    with sigp stop-and-store-status. The kexec code or the boot-loader
580  *    stored the registers of the boot CPU in the memory of the old system.
581  * 4) kdump and the old kernel stored the CPU state
582  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
583  *    This case does not exist for s390 anymore, setup_arch explicitly
584  *    deactivates the elfcorehdr= kernel parameter
585  */
586 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
587                                      bool is_boot_cpu, unsigned long page)
588 {
589         __vector128 *vxrs = (__vector128 *) page;
590 
591         if (is_boot_cpu)
592                 vxrs = boot_cpu_vector_save_area;
593         else
594                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
595         save_area_add_vxrs(sa, vxrs);
596 }
597 
598 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
599                                      bool is_boot_cpu, unsigned long page)
600 {
601         void *regs = (void *) page;
602 
603         if (is_boot_cpu)
604                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
605         else
606                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
607         save_area_add_regs(sa, regs);
608 }
609 
610 void __init smp_save_dump_cpus(void)
611 {
612         int addr, boot_cpu_addr, max_cpu_addr;
613         struct save_area *sa;
614         unsigned long page;
615         bool is_boot_cpu;
616 
617         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
618                 /* No previous system present, normal boot. */
619                 return;
620         /* Allocate a page as dumping area for the store status sigps */
621         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
622         /* Set multi-threading state to the previous system. */
623         pcpu_set_smt(sclp.mtid_prev);
624         boot_cpu_addr = stap();
625         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
626         for (addr = 0; addr <= max_cpu_addr; addr++) {
627                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
628                     SIGP_CC_NOT_OPERATIONAL)
629                         continue;
630                 is_boot_cpu = (addr == boot_cpu_addr);
631                 /* Allocate save area */
632                 sa = save_area_alloc(is_boot_cpu);
633                 if (!sa)
634                         panic("could not allocate memory for save area\n");
635                 if (MACHINE_HAS_VX)
636                         /* Get the vector registers */
637                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
638                 /*
639                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
640                  * of the boot CPU are stored in the HSA. To retrieve
641                  * these registers an SCLP request is required which is
642                  * done by drivers/s390/char/zcore.c:init_cpu_info()
643                  */
644                 if (!is_boot_cpu || OLDMEM_BASE)
645                         /* Get the CPU registers */
646                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
647         }
648         memblock_free(page, PAGE_SIZE);
649         diag308_reset();
650         pcpu_set_smt(0);
651 }
652 #endif /* CONFIG_CRASH_DUMP */
653 
654 void smp_cpu_set_polarization(int cpu, int val)
655 {
656         pcpu_devices[cpu].polarization = val;
657 }
658 
659 int smp_cpu_get_polarization(int cpu)
660 {
661         return pcpu_devices[cpu].polarization;
662 }
663 
664 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
665 {
666         static int use_sigp_detection;
667         int address;
668 
669         if (use_sigp_detection || sclp_get_core_info(info, early)) {
670                 use_sigp_detection = 1;
671                 for (address = 0;
672                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
673                      address += (1U << smp_cpu_mt_shift)) {
674                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
675                             SIGP_CC_NOT_OPERATIONAL)
676                                 continue;
677                         info->core[info->configured].core_id =
678                                 address >> smp_cpu_mt_shift;
679                         info->configured++;
680                 }
681                 info->combined = info->configured;
682         }
683 }
684 
685 static int smp_add_present_cpu(int cpu);
686 
687 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
688 {
689         struct pcpu *pcpu;
690         cpumask_t avail;
691         int cpu, nr, i, j;
692         u16 address;
693 
694         nr = 0;
695         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
696         cpu = cpumask_first(&avail);
697         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
698                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
699                         continue;
700                 address = info->core[i].core_id << smp_cpu_mt_shift;
701                 for (j = 0; j <= smp_cpu_mtid; j++) {
702                         if (pcpu_find_address(cpu_present_mask, address + j))
703                                 continue;
704                         pcpu = pcpu_devices + cpu;
705                         pcpu->address = address + j;
706                         pcpu->state =
707                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
708                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
709                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
710                         set_cpu_present(cpu, true);
711                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
712                                 set_cpu_present(cpu, false);
713                         else
714                                 nr++;
715                         cpu = cpumask_next(cpu, &avail);
716                         if (cpu >= nr_cpu_ids)
717                                 break;
718                 }
719         }
720         return nr;
721 }
722 
723 void __init smp_detect_cpus(void)
724 {
725         unsigned int cpu, mtid, c_cpus, s_cpus;
726         struct sclp_core_info *info;
727         u16 address;
728 
729         /* Get CPU information */
730         info = memblock_virt_alloc(sizeof(*info), 8);
731         smp_get_core_info(info, 1);
732         /* Find boot CPU type */
733         if (sclp.has_core_type) {
734                 address = stap();
735                 for (cpu = 0; cpu < info->combined; cpu++)
736                         if (info->core[cpu].core_id == address) {
737                                 /* The boot cpu dictates the cpu type. */
738                                 boot_core_type = info->core[cpu].type;
739                                 break;
740                         }
741                 if (cpu >= info->combined)
742                         panic("Could not find boot CPU type");
743         }
744 
745         /* Set multi-threading state for the current system */
746         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
747         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
748         pcpu_set_smt(mtid);
749 
750         /* Print number of CPUs */
751         c_cpus = s_cpus = 0;
752         for (cpu = 0; cpu < info->combined; cpu++) {
753                 if (sclp.has_core_type &&
754                     info->core[cpu].type != boot_core_type)
755                         continue;
756                 if (cpu < info->configured)
757                         c_cpus += smp_cpu_mtid + 1;
758                 else
759                         s_cpus += smp_cpu_mtid + 1;
760         }
761         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
762 
763         /* Add CPUs present at boot */
764         get_online_cpus();
765         __smp_rescan_cpus(info, 0);
766         put_online_cpus();
767         memblock_free_early((unsigned long)info, sizeof(*info));
768 }
769 
770 /*
771  *      Activate a secondary processor.
772  */
773 static void smp_start_secondary(void *cpuvoid)
774 {
775         S390_lowcore.last_update_clock = get_tod_clock();
776         S390_lowcore.restart_stack = (unsigned long) restart_stack;
777         S390_lowcore.restart_fn = (unsigned long) do_restart;
778         S390_lowcore.restart_data = 0;
779         S390_lowcore.restart_source = -1UL;
780         restore_access_regs(S390_lowcore.access_regs_save_area);
781         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
782         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
783         cpu_init();
784         preempt_disable();
785         init_cpu_timer();
786         vtime_init();
787         pfault_init();
788         notify_cpu_starting(smp_processor_id());
789         set_cpu_online(smp_processor_id(), true);
790         inc_irq_stat(CPU_RST);
791         local_irq_enable();
792         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
793 }
794 
795 /* Upping and downing of CPUs */
796 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
797 {
798         struct pcpu *pcpu;
799         int base, i, rc;
800 
801         pcpu = pcpu_devices + cpu;
802         if (pcpu->state != CPU_STATE_CONFIGURED)
803                 return -EIO;
804         base = smp_get_base_cpu(cpu);
805         for (i = 0; i <= smp_cpu_mtid; i++) {
806                 if (base + i < nr_cpu_ids)
807                         if (cpu_online(base + i))
808                                 break;
809         }
810         /*
811          * If this is the first CPU of the core to get online
812          * do an initial CPU reset.
813          */
814         if (i > smp_cpu_mtid &&
815             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
816             SIGP_CC_ORDER_CODE_ACCEPTED)
817                 return -EIO;
818 
819         rc = pcpu_alloc_lowcore(pcpu, cpu);
820         if (rc)
821                 return rc;
822         pcpu_prepare_secondary(pcpu, cpu);
823         pcpu_attach_task(pcpu, tidle);
824         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
825         /* Wait until cpu puts itself in the online & active maps */
826         while (!cpu_online(cpu))
827                 cpu_relax();
828         return 0;
829 }
830 
831 static unsigned int setup_possible_cpus __initdata;
832 
833 static int __init _setup_possible_cpus(char *s)
834 {
835         get_option(&s, &setup_possible_cpus);
836         return 0;
837 }
838 early_param("possible_cpus", _setup_possible_cpus);
839 
840 #ifdef CONFIG_HOTPLUG_CPU
841 
842 int __cpu_disable(void)
843 {
844         unsigned long cregs[16];
845 
846         /* Handle possible pending IPIs */
847         smp_handle_ext_call();
848         set_cpu_online(smp_processor_id(), false);
849         /* Disable pseudo page faults on this cpu. */
850         pfault_fini();
851         /* Disable interrupt sources via control register. */
852         __ctl_store(cregs, 0, 15);
853         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
854         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
855         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
856         __ctl_load(cregs, 0, 15);
857         clear_cpu_flag(CIF_NOHZ_DELAY);
858         return 0;
859 }
860 
861 void __cpu_die(unsigned int cpu)
862 {
863         struct pcpu *pcpu;
864 
865         /* Wait until target cpu is down */
866         pcpu = pcpu_devices + cpu;
867         while (!pcpu_stopped(pcpu))
868                 cpu_relax();
869         pcpu_free_lowcore(pcpu);
870         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
871         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
872 }
873 
874 void __noreturn cpu_die(void)
875 {
876         idle_task_exit();
877         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
878         for (;;) ;
879 }
880 
881 #endif /* CONFIG_HOTPLUG_CPU */
882 
883 void __init smp_fill_possible_mask(void)
884 {
885         unsigned int possible, sclp_max, cpu;
886 
887         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
888         sclp_max = min(smp_max_threads, sclp_max);
889         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
890         possible = setup_possible_cpus ?: nr_cpu_ids;
891         possible = min(possible, sclp_max);
892         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
893                 set_cpu_possible(cpu, true);
894 }
895 
896 void __init smp_prepare_cpus(unsigned int max_cpus)
897 {
898         /* request the 0x1201 emergency signal external interrupt */
899         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
900                 panic("Couldn't request external interrupt 0x1201");
901         /* request the 0x1202 external call external interrupt */
902         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
903                 panic("Couldn't request external interrupt 0x1202");
904 }
905 
906 void __init smp_prepare_boot_cpu(void)
907 {
908         struct pcpu *pcpu = pcpu_devices;
909 
910         pcpu->state = CPU_STATE_CONFIGURED;
911         pcpu->address = stap();
912         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
913         S390_lowcore.percpu_offset = __per_cpu_offset[0];
914         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
915         set_cpu_present(0, true);
916         set_cpu_online(0, true);
917 }
918 
919 void __init smp_cpus_done(unsigned int max_cpus)
920 {
921 }
922 
923 void __init smp_setup_processor_id(void)
924 {
925         S390_lowcore.cpu_nr = 0;
926         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
927 }
928 
929 /*
930  * the frequency of the profiling timer can be changed
931  * by writing a multiplier value into /proc/profile.
932  *
933  * usually you want to run this on all CPUs ;)
934  */
935 int setup_profiling_timer(unsigned int multiplier)
936 {
937         return 0;
938 }
939 
940 #ifdef CONFIG_HOTPLUG_CPU
941 static ssize_t cpu_configure_show(struct device *dev,
942                                   struct device_attribute *attr, char *buf)
943 {
944         ssize_t count;
945 
946         mutex_lock(&smp_cpu_state_mutex);
947         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
948         mutex_unlock(&smp_cpu_state_mutex);
949         return count;
950 }
951 
952 static ssize_t cpu_configure_store(struct device *dev,
953                                    struct device_attribute *attr,
954                                    const char *buf, size_t count)
955 {
956         struct pcpu *pcpu;
957         int cpu, val, rc, i;
958         char delim;
959 
960         if (sscanf(buf, "%d %c", &val, &delim) != 1)
961                 return -EINVAL;
962         if (val != 0 && val != 1)
963                 return -EINVAL;
964         get_online_cpus();
965         mutex_lock(&smp_cpu_state_mutex);
966         rc = -EBUSY;
967         /* disallow configuration changes of online cpus and cpu 0 */
968         cpu = dev->id;
969         cpu = smp_get_base_cpu(cpu);
970         if (cpu == 0)
971                 goto out;
972         for (i = 0; i <= smp_cpu_mtid; i++)
973                 if (cpu_online(cpu + i))
974                         goto out;
975         pcpu = pcpu_devices + cpu;
976         rc = 0;
977         switch (val) {
978         case 0:
979                 if (pcpu->state != CPU_STATE_CONFIGURED)
980                         break;
981                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
982                 if (rc)
983                         break;
984                 for (i = 0; i <= smp_cpu_mtid; i++) {
985                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
986                                 continue;
987                         pcpu[i].state = CPU_STATE_STANDBY;
988                         smp_cpu_set_polarization(cpu + i,
989                                                  POLARIZATION_UNKNOWN);
990                 }
991                 topology_expect_change();
992                 break;
993         case 1:
994                 if (pcpu->state != CPU_STATE_STANDBY)
995                         break;
996                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
997                 if (rc)
998                         break;
999                 for (i = 0; i <= smp_cpu_mtid; i++) {
1000                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1001                                 continue;
1002                         pcpu[i].state = CPU_STATE_CONFIGURED;
1003                         smp_cpu_set_polarization(cpu + i,
1004                                                  POLARIZATION_UNKNOWN);
1005                 }
1006                 topology_expect_change();
1007                 break;
1008         default:
1009                 break;
1010         }
1011 out:
1012         mutex_unlock(&smp_cpu_state_mutex);
1013         put_online_cpus();
1014         return rc ? rc : count;
1015 }
1016 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1017 #endif /* CONFIG_HOTPLUG_CPU */
1018 
1019 static ssize_t show_cpu_address(struct device *dev,
1020                                 struct device_attribute *attr, char *buf)
1021 {
1022         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1023 }
1024 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1025 
1026 static struct attribute *cpu_common_attrs[] = {
1027 #ifdef CONFIG_HOTPLUG_CPU
1028         &dev_attr_configure.attr,
1029 #endif
1030         &dev_attr_address.attr,
1031         NULL,
1032 };
1033 
1034 static struct attribute_group cpu_common_attr_group = {
1035         .attrs = cpu_common_attrs,
1036 };
1037 
1038 static struct attribute *cpu_online_attrs[] = {
1039         &dev_attr_idle_count.attr,
1040         &dev_attr_idle_time_us.attr,
1041         NULL,
1042 };
1043 
1044 static struct attribute_group cpu_online_attr_group = {
1045         .attrs = cpu_online_attrs,
1046 };
1047 
1048 static int smp_cpu_online(unsigned int cpu)
1049 {
1050         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1051 
1052         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1053 }
1054 static int smp_cpu_pre_down(unsigned int cpu)
1055 {
1056         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1057 
1058         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1059         return 0;
1060 }
1061 
1062 static int smp_add_present_cpu(int cpu)
1063 {
1064         struct device *s;
1065         struct cpu *c;
1066         int rc;
1067 
1068         c = kzalloc(sizeof(*c), GFP_KERNEL);
1069         if (!c)
1070                 return -ENOMEM;
1071         per_cpu(cpu_device, cpu) = c;
1072         s = &c->dev;
1073         c->hotpluggable = 1;
1074         rc = register_cpu(c, cpu);
1075         if (rc)
1076                 goto out;
1077         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1078         if (rc)
1079                 goto out_cpu;
1080         rc = topology_cpu_init(c);
1081         if (rc)
1082                 goto out_topology;
1083         return 0;
1084 
1085 out_topology:
1086         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1087 out_cpu:
1088 #ifdef CONFIG_HOTPLUG_CPU
1089         unregister_cpu(c);
1090 #endif
1091 out:
1092         return rc;
1093 }
1094 
1095 #ifdef CONFIG_HOTPLUG_CPU
1096 
1097 int __ref smp_rescan_cpus(void)
1098 {
1099         struct sclp_core_info *info;
1100         int nr;
1101 
1102         info = kzalloc(sizeof(*info), GFP_KERNEL);
1103         if (!info)
1104                 return -ENOMEM;
1105         smp_get_core_info(info, 0);
1106         get_online_cpus();
1107         mutex_lock(&smp_cpu_state_mutex);
1108         nr = __smp_rescan_cpus(info, 1);
1109         mutex_unlock(&smp_cpu_state_mutex);
1110         put_online_cpus();
1111         kfree(info);
1112         if (nr)
1113                 topology_schedule_update();
1114         return 0;
1115 }
1116 
1117 static ssize_t __ref rescan_store(struct device *dev,
1118                                   struct device_attribute *attr,
1119                                   const char *buf,
1120                                   size_t count)
1121 {
1122         int rc;
1123 
1124         rc = smp_rescan_cpus();
1125         return rc ? rc : count;
1126 }
1127 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1128 #endif /* CONFIG_HOTPLUG_CPU */
1129 
1130 static int __init s390_smp_init(void)
1131 {
1132         int cpu, rc = 0;
1133 
1134 #ifdef CONFIG_HOTPLUG_CPU
1135         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1136         if (rc)
1137                 return rc;
1138 #endif
1139         for_each_present_cpu(cpu) {
1140                 rc = smp_add_present_cpu(cpu);
1141                 if (rc)
1142                         goto out;
1143         }
1144 
1145         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1146                                smp_cpu_online, smp_cpu_pre_down);
1147 out:
1148         return rc;
1149 }
1150 subsys_initcall(s390_smp_init);
1151 

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