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TOMOYO Linux Cross Reference
Linux/arch/s390/kernel/smp.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  SMP related functions
  4  *
  5  *    Copyright IBM Corp. 1999, 2012
  6  *    Author(s): Denis Joseph Barrow,
  7  *               Martin Schwidefsky <schwidefsky@de.ibm.com>,
  8  *               Heiko Carstens <heiko.carstens@de.ibm.com>,
  9  *
 10  *  based on other smp stuff by
 11  *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
 12  *    (c) 1998 Ingo Molnar
 13  *
 14  * The code outside of smp.c uses logical cpu numbers, only smp.c does
 15  * the translation of logical to physical cpu ids. All new code that
 16  * operates on physical cpu numbers needs to go into smp.c.
 17  */
 18 
 19 #define KMSG_COMPONENT "cpu"
 20 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 21 
 22 #include <linux/workqueue.h>
 23 #include <linux/bootmem.h>
 24 #include <linux/export.h>
 25 #include <linux/init.h>
 26 #include <linux/mm.h>
 27 #include <linux/err.h>
 28 #include <linux/spinlock.h>
 29 #include <linux/kernel_stat.h>
 30 #include <linux/kmemleak.h>
 31 #include <linux/delay.h>
 32 #include <linux/interrupt.h>
 33 #include <linux/irqflags.h>
 34 #include <linux/cpu.h>
 35 #include <linux/slab.h>
 36 #include <linux/sched/hotplug.h>
 37 #include <linux/sched/task_stack.h>
 38 #include <linux/crash_dump.h>
 39 #include <linux/memblock.h>
 40 #include <linux/kprobes.h>
 41 #include <asm/asm-offsets.h>
 42 #include <asm/diag.h>
 43 #include <asm/switch_to.h>
 44 #include <asm/facility.h>
 45 #include <asm/ipl.h>
 46 #include <asm/setup.h>
 47 #include <asm/irq.h>
 48 #include <asm/tlbflush.h>
 49 #include <asm/vtimer.h>
 50 #include <asm/lowcore.h>
 51 #include <asm/sclp.h>
 52 #include <asm/vdso.h>
 53 #include <asm/debug.h>
 54 #include <asm/os_info.h>
 55 #include <asm/sigp.h>
 56 #include <asm/idle.h>
 57 #include <asm/nmi.h>
 58 #include <asm/topology.h>
 59 #include "entry.h"
 60 
 61 enum {
 62         ec_schedule = 0,
 63         ec_call_function_single,
 64         ec_stop_cpu,
 65 };
 66 
 67 enum {
 68         CPU_STATE_STANDBY,
 69         CPU_STATE_CONFIGURED,
 70 };
 71 
 72 static DEFINE_PER_CPU(struct cpu *, cpu_device);
 73 
 74 struct pcpu {
 75         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
 76         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
 77         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
 78         signed char state;              /* physical cpu state */
 79         signed char polarization;       /* physical polarization */
 80         u16 address;                    /* physical cpu address */
 81 };
 82 
 83 static u8 boot_core_type;
 84 static struct pcpu pcpu_devices[NR_CPUS];
 85 
 86 unsigned int smp_cpu_mt_shift;
 87 EXPORT_SYMBOL(smp_cpu_mt_shift);
 88 
 89 unsigned int smp_cpu_mtid;
 90 EXPORT_SYMBOL(smp_cpu_mtid);
 91 
 92 #ifdef CONFIG_CRASH_DUMP
 93 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
 94 #endif
 95 
 96 static unsigned int smp_max_threads __initdata = -1U;
 97 
 98 static int __init early_nosmt(char *s)
 99 {
100         smp_max_threads = 1;
101         return 0;
102 }
103 early_param("nosmt", early_nosmt);
104 
105 static int __init early_smt(char *s)
106 {
107         get_option(&s, &smp_max_threads);
108         return 0;
109 }
110 early_param("smt", early_smt);
111 
112 /*
113  * The smp_cpu_state_mutex must be held when changing the state or polarization
114  * member of a pcpu data structure within the pcpu_devices arreay.
115  */
116 DEFINE_MUTEX(smp_cpu_state_mutex);
117 
118 /*
119  * Signal processor helper functions.
120  */
121 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
122 {
123         int cc;
124 
125         while (1) {
126                 cc = __pcpu_sigp(addr, order, parm, NULL);
127                 if (cc != SIGP_CC_BUSY)
128                         return cc;
129                 cpu_relax();
130         }
131 }
132 
133 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
134 {
135         int cc, retry;
136 
137         for (retry = 0; ; retry++) {
138                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
139                 if (cc != SIGP_CC_BUSY)
140                         break;
141                 if (retry >= 3)
142                         udelay(10);
143         }
144         return cc;
145 }
146 
147 static inline int pcpu_stopped(struct pcpu *pcpu)
148 {
149         u32 uninitialized_var(status);
150 
151         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
152                         0, &status) != SIGP_CC_STATUS_STORED)
153                 return 0;
154         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
155 }
156 
157 static inline int pcpu_running(struct pcpu *pcpu)
158 {
159         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
160                         0, NULL) != SIGP_CC_STATUS_STORED)
161                 return 1;
162         /* Status stored condition code is equivalent to cpu not running. */
163         return 0;
164 }
165 
166 /*
167  * Find struct pcpu by cpu address.
168  */
169 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
170 {
171         int cpu;
172 
173         for_each_cpu(cpu, mask)
174                 if (pcpu_devices[cpu].address == address)
175                         return pcpu_devices + cpu;
176         return NULL;
177 }
178 
179 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
180 {
181         int order;
182 
183         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
184                 return;
185         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
186         pcpu->ec_clk = get_tod_clock_fast();
187         pcpu_sigp_retry(pcpu, order, 0);
188 }
189 
190 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
191 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
192 
193 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
194 {
195         unsigned long async_stack, panic_stack;
196         struct lowcore *lc;
197 
198         if (pcpu != &pcpu_devices[0]) {
199                 pcpu->lowcore = (struct lowcore *)
200                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
201                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
202                 panic_stack = __get_free_page(GFP_KERNEL);
203                 if (!pcpu->lowcore || !panic_stack || !async_stack)
204                         goto out;
205         } else {
206                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
207                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
208         }
209         lc = pcpu->lowcore;
210         memcpy(lc, &S390_lowcore, 512);
211         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
212         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
213         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
214         lc->cpu_nr = cpu;
215         lc->spinlock_lockval = arch_spin_lockval(cpu);
216         lc->spinlock_index = 0;
217         if (nmi_alloc_per_cpu(lc))
218                 goto out;
219         if (vdso_alloc_per_cpu(lc))
220                 goto out_mcesa;
221         lowcore_ptr[cpu] = lc;
222         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
223         return 0;
224 
225 out_mcesa:
226         nmi_free_per_cpu(lc);
227 out:
228         if (pcpu != &pcpu_devices[0]) {
229                 free_page(panic_stack);
230                 free_pages(async_stack, ASYNC_ORDER);
231                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
232         }
233         return -ENOMEM;
234 }
235 
236 #ifdef CONFIG_HOTPLUG_CPU
237 
238 static void pcpu_free_lowcore(struct pcpu *pcpu)
239 {
240         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
241         lowcore_ptr[pcpu - pcpu_devices] = NULL;
242         vdso_free_per_cpu(pcpu->lowcore);
243         nmi_free_per_cpu(pcpu->lowcore);
244         if (pcpu == &pcpu_devices[0])
245                 return;
246         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
247         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
248         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
249 }
250 
251 #endif /* CONFIG_HOTPLUG_CPU */
252 
253 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
254 {
255         struct lowcore *lc = pcpu->lowcore;
256 
257         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
258         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
259         lc->cpu_nr = cpu;
260         lc->spinlock_lockval = arch_spin_lockval(cpu);
261         lc->spinlock_index = 0;
262         lc->percpu_offset = __per_cpu_offset[cpu];
263         lc->kernel_asce = S390_lowcore.kernel_asce;
264         lc->machine_flags = S390_lowcore.machine_flags;
265         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
266         __ctl_store(lc->cregs_save_area, 0, 15);
267         save_access_regs((unsigned int *) lc->access_regs_save_area);
268         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
269                MAX_FACILITY_BIT/8);
270         arch_spin_lock_setup(cpu);
271 }
272 
273 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
274 {
275         struct lowcore *lc = pcpu->lowcore;
276 
277         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
278                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
279         lc->current_task = (unsigned long) tsk;
280         lc->lpp = LPP_MAGIC;
281         lc->current_pid = tsk->pid;
282         lc->user_timer = tsk->thread.user_timer;
283         lc->guest_timer = tsk->thread.guest_timer;
284         lc->system_timer = tsk->thread.system_timer;
285         lc->hardirq_timer = tsk->thread.hardirq_timer;
286         lc->softirq_timer = tsk->thread.softirq_timer;
287         lc->steal_timer = 0;
288 }
289 
290 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
291 {
292         struct lowcore *lc = pcpu->lowcore;
293 
294         lc->restart_stack = lc->kernel_stack;
295         lc->restart_fn = (unsigned long) func;
296         lc->restart_data = (unsigned long) data;
297         lc->restart_source = -1UL;
298         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
299 }
300 
301 /*
302  * Call function via PSW restart on pcpu and stop the current cpu.
303  */
304 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
305                           void *data, unsigned long stack)
306 {
307         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
308         unsigned long source_cpu = stap();
309 
310         __load_psw_mask(PSW_KERNEL_BITS);
311         if (pcpu->address == source_cpu)
312                 func(data);     /* should not return */
313         /* Stop target cpu (if func returns this stops the current cpu). */
314         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
315         /* Restart func on the target cpu and stop the current cpu. */
316         mem_assign_absolute(lc->restart_stack, stack);
317         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
318         mem_assign_absolute(lc->restart_data, (unsigned long) data);
319         mem_assign_absolute(lc->restart_source, source_cpu);
320         asm volatile(
321                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
322                 "       brc     2,0b    # busy, try again\n"
323                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
324                 "       brc     2,1b    # busy, try again\n"
325                 : : "d" (pcpu->address), "d" (source_cpu),
326                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
327                 : "", "1", "cc");
328         for (;;) ;
329 }
330 
331 /*
332  * Enable additional logical cpus for multi-threading.
333  */
334 static int pcpu_set_smt(unsigned int mtid)
335 {
336         int cc;
337 
338         if (smp_cpu_mtid == mtid)
339                 return 0;
340         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
341         if (cc == 0) {
342                 smp_cpu_mtid = mtid;
343                 smp_cpu_mt_shift = 0;
344                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
345                         smp_cpu_mt_shift++;
346                 pcpu_devices[0].address = stap();
347         }
348         return cc;
349 }
350 
351 /*
352  * Call function on an online CPU.
353  */
354 void smp_call_online_cpu(void (*func)(void *), void *data)
355 {
356         struct pcpu *pcpu;
357 
358         /* Use the current cpu if it is online. */
359         pcpu = pcpu_find_address(cpu_online_mask, stap());
360         if (!pcpu)
361                 /* Use the first online cpu. */
362                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
363         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
364 }
365 
366 /*
367  * Call function on the ipl CPU.
368  */
369 void smp_call_ipl_cpu(void (*func)(void *), void *data)
370 {
371         pcpu_delegate(&pcpu_devices[0], func, data,
372                       pcpu_devices->lowcore->panic_stack -
373                       PANIC_FRAME_OFFSET + PAGE_SIZE);
374 }
375 
376 int smp_find_processor_id(u16 address)
377 {
378         int cpu;
379 
380         for_each_present_cpu(cpu)
381                 if (pcpu_devices[cpu].address == address)
382                         return cpu;
383         return -1;
384 }
385 
386 bool arch_vcpu_is_preempted(int cpu)
387 {
388         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
389                 return false;
390         if (pcpu_running(pcpu_devices + cpu))
391                 return false;
392         return true;
393 }
394 EXPORT_SYMBOL(arch_vcpu_is_preempted);
395 
396 void smp_yield_cpu(int cpu)
397 {
398         if (MACHINE_HAS_DIAG9C) {
399                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
400                 asm volatile("diag %0,0,0x9c"
401                              : : "d" (pcpu_devices[cpu].address));
402         } else if (MACHINE_HAS_DIAG44) {
403                 diag_stat_inc_norecursion(DIAG_STAT_X044);
404                 asm volatile("diag 0,0,0x44");
405         }
406 }
407 
408 /*
409  * Send cpus emergency shutdown signal. This gives the cpus the
410  * opportunity to complete outstanding interrupts.
411  */
412 void notrace smp_emergency_stop(void)
413 {
414         cpumask_t cpumask;
415         u64 end;
416         int cpu;
417 
418         cpumask_copy(&cpumask, cpu_online_mask);
419         cpumask_clear_cpu(smp_processor_id(), &cpumask);
420 
421         end = get_tod_clock() + (1000000UL << 12);
422         for_each_cpu(cpu, &cpumask) {
423                 struct pcpu *pcpu = pcpu_devices + cpu;
424                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
425                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
426                                    0, NULL) == SIGP_CC_BUSY &&
427                        get_tod_clock() < end)
428                         cpu_relax();
429         }
430         while (get_tod_clock() < end) {
431                 for_each_cpu(cpu, &cpumask)
432                         if (pcpu_stopped(pcpu_devices + cpu))
433                                 cpumask_clear_cpu(cpu, &cpumask);
434                 if (cpumask_empty(&cpumask))
435                         break;
436                 cpu_relax();
437         }
438 }
439 NOKPROBE_SYMBOL(smp_emergency_stop);
440 
441 /*
442  * Stop all cpus but the current one.
443  */
444 void smp_send_stop(void)
445 {
446         int cpu;
447 
448         /* Disable all interrupts/machine checks */
449         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
450         trace_hardirqs_off();
451 
452         debug_set_critical();
453 
454         if (oops_in_progress)
455                 smp_emergency_stop();
456 
457         /* stop all processors */
458         for_each_online_cpu(cpu) {
459                 if (cpu == smp_processor_id())
460                         continue;
461                 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
462                 while (!pcpu_stopped(pcpu_devices + cpu))
463                         cpu_relax();
464         }
465 }
466 
467 /*
468  * This is the main routine where commands issued by other
469  * cpus are handled.
470  */
471 static void smp_handle_ext_call(void)
472 {
473         unsigned long bits;
474 
475         /* handle bit signal external calls */
476         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
477         if (test_bit(ec_stop_cpu, &bits))
478                 smp_stop_cpu();
479         if (test_bit(ec_schedule, &bits))
480                 scheduler_ipi();
481         if (test_bit(ec_call_function_single, &bits))
482                 generic_smp_call_function_single_interrupt();
483 }
484 
485 static void do_ext_call_interrupt(struct ext_code ext_code,
486                                   unsigned int param32, unsigned long param64)
487 {
488         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
489         smp_handle_ext_call();
490 }
491 
492 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
493 {
494         int cpu;
495 
496         for_each_cpu(cpu, mask)
497                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
498 }
499 
500 void arch_send_call_function_single_ipi(int cpu)
501 {
502         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
503 }
504 
505 /*
506  * this function sends a 'reschedule' IPI to another CPU.
507  * it goes straight through and wastes no time serializing
508  * anything. Worst case is that we lose a reschedule ...
509  */
510 void smp_send_reschedule(int cpu)
511 {
512         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
513 }
514 
515 /*
516  * parameter area for the set/clear control bit callbacks
517  */
518 struct ec_creg_mask_parms {
519         unsigned long orval;
520         unsigned long andval;
521         int cr;
522 };
523 
524 /*
525  * callback for setting/clearing control bits
526  */
527 static void smp_ctl_bit_callback(void *info)
528 {
529         struct ec_creg_mask_parms *pp = info;
530         unsigned long cregs[16];
531 
532         __ctl_store(cregs, 0, 15);
533         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
534         __ctl_load(cregs, 0, 15);
535 }
536 
537 /*
538  * Set a bit in a control register of all cpus
539  */
540 void smp_ctl_set_bit(int cr, int bit)
541 {
542         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
543 
544         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
545 }
546 EXPORT_SYMBOL(smp_ctl_set_bit);
547 
548 /*
549  * Clear a bit in a control register of all cpus
550  */
551 void smp_ctl_clear_bit(int cr, int bit)
552 {
553         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
554 
555         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
556 }
557 EXPORT_SYMBOL(smp_ctl_clear_bit);
558 
559 #ifdef CONFIG_CRASH_DUMP
560 
561 int smp_store_status(int cpu)
562 {
563         struct pcpu *pcpu = pcpu_devices + cpu;
564         unsigned long pa;
565 
566         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
567         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
568                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
569                 return -EIO;
570         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
571                 return 0;
572         pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
573         if (MACHINE_HAS_GS)
574                 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
575         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
576                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
577                 return -EIO;
578         return 0;
579 }
580 
581 /*
582  * Collect CPU state of the previous, crashed system.
583  * There are four cases:
584  * 1) standard zfcp dump
585  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
586  *    The state for all CPUs except the boot CPU needs to be collected
587  *    with sigp stop-and-store-status. The boot CPU state is located in
588  *    the absolute lowcore of the memory stored in the HSA. The zcore code
589  *    will copy the boot CPU state from the HSA.
590  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
591  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
592  *    The state for all CPUs except the boot CPU needs to be collected
593  *    with sigp stop-and-store-status. The firmware or the boot-loader
594  *    stored the registers of the boot CPU in the absolute lowcore in the
595  *    memory of the old system.
596  * 3) kdump and the old kernel did not store the CPU state,
597  *    or stand-alone kdump for DASD
598  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
599  *    The state for all CPUs except the boot CPU needs to be collected
600  *    with sigp stop-and-store-status. The kexec code or the boot-loader
601  *    stored the registers of the boot CPU in the memory of the old system.
602  * 4) kdump and the old kernel stored the CPU state
603  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
604  *    This case does not exist for s390 anymore, setup_arch explicitly
605  *    deactivates the elfcorehdr= kernel parameter
606  */
607 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
608                                      bool is_boot_cpu, unsigned long page)
609 {
610         __vector128 *vxrs = (__vector128 *) page;
611 
612         if (is_boot_cpu)
613                 vxrs = boot_cpu_vector_save_area;
614         else
615                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
616         save_area_add_vxrs(sa, vxrs);
617 }
618 
619 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
620                                      bool is_boot_cpu, unsigned long page)
621 {
622         void *regs = (void *) page;
623 
624         if (is_boot_cpu)
625                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
626         else
627                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
628         save_area_add_regs(sa, regs);
629 }
630 
631 void __init smp_save_dump_cpus(void)
632 {
633         int addr, boot_cpu_addr, max_cpu_addr;
634         struct save_area *sa;
635         unsigned long page;
636         bool is_boot_cpu;
637 
638         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
639                 /* No previous system present, normal boot. */
640                 return;
641         /* Allocate a page as dumping area for the store status sigps */
642         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
643         /* Set multi-threading state to the previous system. */
644         pcpu_set_smt(sclp.mtid_prev);
645         boot_cpu_addr = stap();
646         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
647         for (addr = 0; addr <= max_cpu_addr; addr++) {
648                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
649                     SIGP_CC_NOT_OPERATIONAL)
650                         continue;
651                 is_boot_cpu = (addr == boot_cpu_addr);
652                 /* Allocate save area */
653                 sa = save_area_alloc(is_boot_cpu);
654                 if (!sa)
655                         panic("could not allocate memory for save area\n");
656                 if (MACHINE_HAS_VX)
657                         /* Get the vector registers */
658                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
659                 /*
660                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
661                  * of the boot CPU are stored in the HSA. To retrieve
662                  * these registers an SCLP request is required which is
663                  * done by drivers/s390/char/zcore.c:init_cpu_info()
664                  */
665                 if (!is_boot_cpu || OLDMEM_BASE)
666                         /* Get the CPU registers */
667                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
668         }
669         memblock_free(page, PAGE_SIZE);
670         diag308_reset();
671         pcpu_set_smt(0);
672 }
673 #endif /* CONFIG_CRASH_DUMP */
674 
675 void smp_cpu_set_polarization(int cpu, int val)
676 {
677         pcpu_devices[cpu].polarization = val;
678 }
679 
680 int smp_cpu_get_polarization(int cpu)
681 {
682         return pcpu_devices[cpu].polarization;
683 }
684 
685 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
686 {
687         static int use_sigp_detection;
688         int address;
689 
690         if (use_sigp_detection || sclp_get_core_info(info, early)) {
691                 use_sigp_detection = 1;
692                 for (address = 0;
693                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
694                      address += (1U << smp_cpu_mt_shift)) {
695                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
696                             SIGP_CC_NOT_OPERATIONAL)
697                                 continue;
698                         info->core[info->configured].core_id =
699                                 address >> smp_cpu_mt_shift;
700                         info->configured++;
701                 }
702                 info->combined = info->configured;
703         }
704 }
705 
706 static int smp_add_present_cpu(int cpu);
707 
708 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
709 {
710         struct pcpu *pcpu;
711         cpumask_t avail;
712         int cpu, nr, i, j;
713         u16 address;
714 
715         nr = 0;
716         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
717         cpu = cpumask_first(&avail);
718         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
719                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
720                         continue;
721                 address = info->core[i].core_id << smp_cpu_mt_shift;
722                 for (j = 0; j <= smp_cpu_mtid; j++) {
723                         if (pcpu_find_address(cpu_present_mask, address + j))
724                                 continue;
725                         pcpu = pcpu_devices + cpu;
726                         pcpu->address = address + j;
727                         pcpu->state =
728                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
729                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
730                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
731                         set_cpu_present(cpu, true);
732                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
733                                 set_cpu_present(cpu, false);
734                         else
735                                 nr++;
736                         cpu = cpumask_next(cpu, &avail);
737                         if (cpu >= nr_cpu_ids)
738                                 break;
739                 }
740         }
741         return nr;
742 }
743 
744 void __init smp_detect_cpus(void)
745 {
746         unsigned int cpu, mtid, c_cpus, s_cpus;
747         struct sclp_core_info *info;
748         u16 address;
749 
750         /* Get CPU information */
751         info = memblock_virt_alloc(sizeof(*info), 8);
752         smp_get_core_info(info, 1);
753         /* Find boot CPU type */
754         if (sclp.has_core_type) {
755                 address = stap();
756                 for (cpu = 0; cpu < info->combined; cpu++)
757                         if (info->core[cpu].core_id == address) {
758                                 /* The boot cpu dictates the cpu type. */
759                                 boot_core_type = info->core[cpu].type;
760                                 break;
761                         }
762                 if (cpu >= info->combined)
763                         panic("Could not find boot CPU type");
764         }
765 
766         /* Set multi-threading state for the current system */
767         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
768         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
769         pcpu_set_smt(mtid);
770 
771         /* Print number of CPUs */
772         c_cpus = s_cpus = 0;
773         for (cpu = 0; cpu < info->combined; cpu++) {
774                 if (sclp.has_core_type &&
775                     info->core[cpu].type != boot_core_type)
776                         continue;
777                 if (cpu < info->configured)
778                         c_cpus += smp_cpu_mtid + 1;
779                 else
780                         s_cpus += smp_cpu_mtid + 1;
781         }
782         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
783 
784         /* Add CPUs present at boot */
785         get_online_cpus();
786         __smp_rescan_cpus(info, 0);
787         put_online_cpus();
788         memblock_free_early((unsigned long)info, sizeof(*info));
789 }
790 
791 /*
792  *      Activate a secondary processor.
793  */
794 static void smp_start_secondary(void *cpuvoid)
795 {
796         int cpu = smp_processor_id();
797 
798         S390_lowcore.last_update_clock = get_tod_clock();
799         S390_lowcore.restart_stack = (unsigned long) restart_stack;
800         S390_lowcore.restart_fn = (unsigned long) do_restart;
801         S390_lowcore.restart_data = 0;
802         S390_lowcore.restart_source = -1UL;
803         restore_access_regs(S390_lowcore.access_regs_save_area);
804         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
805         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
806         cpu_init();
807         preempt_disable();
808         init_cpu_timer();
809         vtime_init();
810         pfault_init();
811         notify_cpu_starting(cpu);
812         if (topology_cpu_dedicated(cpu))
813                 set_cpu_flag(CIF_DEDICATED_CPU);
814         else
815                 clear_cpu_flag(CIF_DEDICATED_CPU);
816         set_cpu_online(cpu, true);
817         inc_irq_stat(CPU_RST);
818         local_irq_enable();
819         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
820 }
821 
822 /* Upping and downing of CPUs */
823 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
824 {
825         struct pcpu *pcpu;
826         int base, i, rc;
827 
828         pcpu = pcpu_devices + cpu;
829         if (pcpu->state != CPU_STATE_CONFIGURED)
830                 return -EIO;
831         base = smp_get_base_cpu(cpu);
832         for (i = 0; i <= smp_cpu_mtid; i++) {
833                 if (base + i < nr_cpu_ids)
834                         if (cpu_online(base + i))
835                                 break;
836         }
837         /*
838          * If this is the first CPU of the core to get online
839          * do an initial CPU reset.
840          */
841         if (i > smp_cpu_mtid &&
842             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
843             SIGP_CC_ORDER_CODE_ACCEPTED)
844                 return -EIO;
845 
846         rc = pcpu_alloc_lowcore(pcpu, cpu);
847         if (rc)
848                 return rc;
849         pcpu_prepare_secondary(pcpu, cpu);
850         pcpu_attach_task(pcpu, tidle);
851         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
852         /* Wait until cpu puts itself in the online & active maps */
853         while (!cpu_online(cpu))
854                 cpu_relax();
855         return 0;
856 }
857 
858 static unsigned int setup_possible_cpus __initdata;
859 
860 static int __init _setup_possible_cpus(char *s)
861 {
862         get_option(&s, &setup_possible_cpus);
863         return 0;
864 }
865 early_param("possible_cpus", _setup_possible_cpus);
866 
867 #ifdef CONFIG_HOTPLUG_CPU
868 
869 int __cpu_disable(void)
870 {
871         unsigned long cregs[16];
872 
873         /* Handle possible pending IPIs */
874         smp_handle_ext_call();
875         set_cpu_online(smp_processor_id(), false);
876         /* Disable pseudo page faults on this cpu. */
877         pfault_fini();
878         /* Disable interrupt sources via control register. */
879         __ctl_store(cregs, 0, 15);
880         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
881         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
882         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
883         __ctl_load(cregs, 0, 15);
884         clear_cpu_flag(CIF_NOHZ_DELAY);
885         return 0;
886 }
887 
888 void __cpu_die(unsigned int cpu)
889 {
890         struct pcpu *pcpu;
891 
892         /* Wait until target cpu is down */
893         pcpu = pcpu_devices + cpu;
894         while (!pcpu_stopped(pcpu))
895                 cpu_relax();
896         pcpu_free_lowcore(pcpu);
897         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
898         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
899 }
900 
901 void __noreturn cpu_die(void)
902 {
903         idle_task_exit();
904         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
905         for (;;) ;
906 }
907 
908 #endif /* CONFIG_HOTPLUG_CPU */
909 
910 void __init smp_fill_possible_mask(void)
911 {
912         unsigned int possible, sclp_max, cpu;
913 
914         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
915         sclp_max = min(smp_max_threads, sclp_max);
916         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
917         possible = setup_possible_cpus ?: nr_cpu_ids;
918         possible = min(possible, sclp_max);
919         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
920                 set_cpu_possible(cpu, true);
921 }
922 
923 void __init smp_prepare_cpus(unsigned int max_cpus)
924 {
925         /* request the 0x1201 emergency signal external interrupt */
926         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
927                 panic("Couldn't request external interrupt 0x1201");
928         /* request the 0x1202 external call external interrupt */
929         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
930                 panic("Couldn't request external interrupt 0x1202");
931 }
932 
933 void __init smp_prepare_boot_cpu(void)
934 {
935         struct pcpu *pcpu = pcpu_devices;
936 
937         WARN_ON(!cpu_present(0) || !cpu_online(0));
938         pcpu->state = CPU_STATE_CONFIGURED;
939         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
940         S390_lowcore.percpu_offset = __per_cpu_offset[0];
941         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
942 }
943 
944 void __init smp_cpus_done(unsigned int max_cpus)
945 {
946 }
947 
948 void __init smp_setup_processor_id(void)
949 {
950         pcpu_devices[0].address = stap();
951         S390_lowcore.cpu_nr = 0;
952         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
953         S390_lowcore.spinlock_index = 0;
954 }
955 
956 /*
957  * the frequency of the profiling timer can be changed
958  * by writing a multiplier value into /proc/profile.
959  *
960  * usually you want to run this on all CPUs ;)
961  */
962 int setup_profiling_timer(unsigned int multiplier)
963 {
964         return 0;
965 }
966 
967 #ifdef CONFIG_HOTPLUG_CPU
968 static ssize_t cpu_configure_show(struct device *dev,
969                                   struct device_attribute *attr, char *buf)
970 {
971         ssize_t count;
972 
973         mutex_lock(&smp_cpu_state_mutex);
974         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
975         mutex_unlock(&smp_cpu_state_mutex);
976         return count;
977 }
978 
979 static ssize_t cpu_configure_store(struct device *dev,
980                                    struct device_attribute *attr,
981                                    const char *buf, size_t count)
982 {
983         struct pcpu *pcpu;
984         int cpu, val, rc, i;
985         char delim;
986 
987         if (sscanf(buf, "%d %c", &val, &delim) != 1)
988                 return -EINVAL;
989         if (val != 0 && val != 1)
990                 return -EINVAL;
991         get_online_cpus();
992         mutex_lock(&smp_cpu_state_mutex);
993         rc = -EBUSY;
994         /* disallow configuration changes of online cpus and cpu 0 */
995         cpu = dev->id;
996         cpu = smp_get_base_cpu(cpu);
997         if (cpu == 0)
998                 goto out;
999         for (i = 0; i <= smp_cpu_mtid; i++)
1000                 if (cpu_online(cpu + i))
1001                         goto out;
1002         pcpu = pcpu_devices + cpu;
1003         rc = 0;
1004         switch (val) {
1005         case 0:
1006                 if (pcpu->state != CPU_STATE_CONFIGURED)
1007                         break;
1008                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1009                 if (rc)
1010                         break;
1011                 for (i = 0; i <= smp_cpu_mtid; i++) {
1012                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1013                                 continue;
1014                         pcpu[i].state = CPU_STATE_STANDBY;
1015                         smp_cpu_set_polarization(cpu + i,
1016                                                  POLARIZATION_UNKNOWN);
1017                 }
1018                 topology_expect_change();
1019                 break;
1020         case 1:
1021                 if (pcpu->state != CPU_STATE_STANDBY)
1022                         break;
1023                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1024                 if (rc)
1025                         break;
1026                 for (i = 0; i <= smp_cpu_mtid; i++) {
1027                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1028                                 continue;
1029                         pcpu[i].state = CPU_STATE_CONFIGURED;
1030                         smp_cpu_set_polarization(cpu + i,
1031                                                  POLARIZATION_UNKNOWN);
1032                 }
1033                 topology_expect_change();
1034                 break;
1035         default:
1036                 break;
1037         }
1038 out:
1039         mutex_unlock(&smp_cpu_state_mutex);
1040         put_online_cpus();
1041         return rc ? rc : count;
1042 }
1043 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1044 #endif /* CONFIG_HOTPLUG_CPU */
1045 
1046 static ssize_t show_cpu_address(struct device *dev,
1047                                 struct device_attribute *attr, char *buf)
1048 {
1049         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1050 }
1051 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1052 
1053 static struct attribute *cpu_common_attrs[] = {
1054 #ifdef CONFIG_HOTPLUG_CPU
1055         &dev_attr_configure.attr,
1056 #endif
1057         &dev_attr_address.attr,
1058         NULL,
1059 };
1060 
1061 static struct attribute_group cpu_common_attr_group = {
1062         .attrs = cpu_common_attrs,
1063 };
1064 
1065 static struct attribute *cpu_online_attrs[] = {
1066         &dev_attr_idle_count.attr,
1067         &dev_attr_idle_time_us.attr,
1068         NULL,
1069 };
1070 
1071 static struct attribute_group cpu_online_attr_group = {
1072         .attrs = cpu_online_attrs,
1073 };
1074 
1075 static int smp_cpu_online(unsigned int cpu)
1076 {
1077         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1078 
1079         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1080 }
1081 static int smp_cpu_pre_down(unsigned int cpu)
1082 {
1083         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1084 
1085         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1086         return 0;
1087 }
1088 
1089 static int smp_add_present_cpu(int cpu)
1090 {
1091         struct device *s;
1092         struct cpu *c;
1093         int rc;
1094 
1095         c = kzalloc(sizeof(*c), GFP_KERNEL);
1096         if (!c)
1097                 return -ENOMEM;
1098         per_cpu(cpu_device, cpu) = c;
1099         s = &c->dev;
1100         c->hotpluggable = 1;
1101         rc = register_cpu(c, cpu);
1102         if (rc)
1103                 goto out;
1104         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1105         if (rc)
1106                 goto out_cpu;
1107         rc = topology_cpu_init(c);
1108         if (rc)
1109                 goto out_topology;
1110         return 0;
1111 
1112 out_topology:
1113         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1114 out_cpu:
1115 #ifdef CONFIG_HOTPLUG_CPU
1116         unregister_cpu(c);
1117 #endif
1118 out:
1119         return rc;
1120 }
1121 
1122 #ifdef CONFIG_HOTPLUG_CPU
1123 
1124 int __ref smp_rescan_cpus(void)
1125 {
1126         struct sclp_core_info *info;
1127         int nr;
1128 
1129         info = kzalloc(sizeof(*info), GFP_KERNEL);
1130         if (!info)
1131                 return -ENOMEM;
1132         smp_get_core_info(info, 0);
1133         get_online_cpus();
1134         mutex_lock(&smp_cpu_state_mutex);
1135         nr = __smp_rescan_cpus(info, 1);
1136         mutex_unlock(&smp_cpu_state_mutex);
1137         put_online_cpus();
1138         kfree(info);
1139         if (nr)
1140                 topology_schedule_update();
1141         return 0;
1142 }
1143 
1144 static ssize_t __ref rescan_store(struct device *dev,
1145                                   struct device_attribute *attr,
1146                                   const char *buf,
1147                                   size_t count)
1148 {
1149         int rc;
1150 
1151         rc = smp_rescan_cpus();
1152         return rc ? rc : count;
1153 }
1154 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1155 #endif /* CONFIG_HOTPLUG_CPU */
1156 
1157 static int __init s390_smp_init(void)
1158 {
1159         int cpu, rc = 0;
1160 
1161 #ifdef CONFIG_HOTPLUG_CPU
1162         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1163         if (rc)
1164                 return rc;
1165 #endif
1166         for_each_present_cpu(cpu) {
1167                 rc = smp_add_present_cpu(cpu);
1168                 if (rc)
1169                         goto out;
1170         }
1171 
1172         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1173                                smp_cpu_online, smp_cpu_pre_down);
1174         rc = rc <= 0 ? rc : 0;
1175 out:
1176         return rc;
1177 }
1178 subsys_initcall(s390_smp_init);
1179 

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