arch/s390/kernel/smp.c

   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/memblock.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/delay.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/irqflags.h>
  33 #include <linux/cpu.h>
  34 #include <linux/slab.h>
  35 #include <linux/sched/hotplug.h>
  36 #include <linux/sched/task_stack.h>
  37 #include <linux/crash_dump.h>
  38 #include <linux/kprobes.h>
  39 #include <asm/asm-offsets.h>
  40 #include <asm/diag.h>
  41 #include <asm/switch_to.h>
  42 #include <asm/facility.h>
  43 #include <asm/ipl.h>
  44 #include <asm/setup.h>
  45 #include <asm/irq.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/vtimer.h>
  48 #include <asm/lowcore.h>
  49 #include <asm/sclp.h>
  50 #include <asm/vdso.h>
  51 #include <asm/debug.h>
  52 #include <asm/os_info.h>
  53 #include <asm/sigp.h>
  54 #include <asm/idle.h>
  55 #include <asm/nmi.h>
  56 #include <asm/stacktrace.h>
  57 #include <asm/topology.h>
  58 #include "entry.h"
  59
  60 enum {
  61         ec_schedule = 0,
  62         ec_call_function_single,
  63         ec_stop_cpu,
  64 };
  65
  66 enum {
  67         CPU_STATE_STANDBY,
  68         CPU_STATE_CONFIGURED,
  69 };
  70
  71 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  72
  73 struct pcpu {
  74         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  75         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  76         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  77         signed char state;              /* physical cpu state */
  78         signed char polarization;       /* physical polarization */
  79         u16 address;                    /* physical cpu address */
  80 };
  81
  82 static u8 boot_core_type;
  83 static struct pcpu pcpu_devices[NR_CPUS];
  84
  85 unsigned int smp_cpu_mt_shift;
  86 EXPORT_SYMBOL(smp_cpu_mt_shift);
  87
  88 unsigned int smp_cpu_mtid;
  89 EXPORT_SYMBOL(smp_cpu_mtid);
  90
  91 #ifdef CONFIG_CRASH_DUMP
  92 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  93 #endif
  94
  95 static unsigned int smp_max_threads __initdata = -1U;
  96
  97 static int __init early_nosmt(char *s)
  98 {
  99         smp_max_threads = 1;
 100         return 0;
 101 }
 102 early_param("nosmt", early_nosmt);
 103
 104 static int __init early_smt(char *s)
 105 {
 106         get_option(&s, &smp_max_threads);
 107         return 0;
 108 }
 109 early_param("smt", early_smt);
 110
 111 /*
 112  * The smp_cpu_state_mutex must be held when changing the state or polarization
 113  * member of a pcpu data structure within the pcpu_devices arreay.
 114  */
 115 DEFINE_MUTEX(smp_cpu_state_mutex);
 116
 117 /*
 118  * Signal processor helper functions.
 119  */
 120 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 121 {
 122         int cc;
 123
 124         while (1) {
 125                 cc = __pcpu_sigp(addr, order, parm, NULL);
 126                 if (cc != SIGP_CC_BUSY)
 127                         return cc;
 128                 cpu_relax();
 129         }
 130 }
 131
 132 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 133 {
 134         int cc, retry;
 135
 136         for (retry = 0; ; retry++) {
 137                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 138                 if (cc != SIGP_CC_BUSY)
 139                         break;
 140                 if (retry >= 3)
 141                         udelay(10);
 142         }
 143         return cc;
 144 }
 145
 146 static inline int pcpu_stopped(struct pcpu *pcpu)
 147 {
 148         u32 uninitialized_var(status);
 149
 150         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 151                         0, &status) != SIGP_CC_STATUS_STORED)
 152                 return 0;
 153         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 154 }
 155
 156 static inline int pcpu_running(struct pcpu *pcpu)
 157 {
 158         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 159                         0, NULL) != SIGP_CC_STATUS_STORED)
 160                 return 1;
 161         /* Status stored condition code is equivalent to cpu not running. */
 162         return 0;
 163 }
 164
 165 /*
 166  * Find struct pcpu by cpu address.
 167  */
 168 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 169 {
 170         int cpu;
 171
 172         for_each_cpu(cpu, mask)
 173                 if (pcpu_devices[cpu].address == address)
 174                         return pcpu_devices + cpu;
 175         return NULL;
 176 }
 177
 178 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 179 {
 180         int order;
 181
 182         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 183                 return;
 184         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 185         pcpu->ec_clk = get_tod_clock_fast();
 186         pcpu_sigp_retry(pcpu, order, 0);
 187 }
 188
 189 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 190 {
 191         unsigned long async_stack, nodat_stack;
 192         struct lowcore *lc;
 193
 194         if (pcpu != &pcpu_devices[0]) {
 195                 pcpu->lowcore = (struct lowcore *)
 196                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 197                 nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
 198                 if (!pcpu->lowcore || !nodat_stack)
 199                         goto out;
 200         } else {
 201                 nodat_stack = pcpu->lowcore->nodat_stack - STACK_INIT_OFFSET;
 202         }
 203         async_stack = stack_alloc();
 204         if (!async_stack)
 205                 goto out;
 206         lc = pcpu->lowcore;
 207         memcpy(lc, &S390_lowcore, 512);
 208         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 209         lc->async_stack = async_stack + STACK_INIT_OFFSET;
 210         lc->nodat_stack = nodat_stack + STACK_INIT_OFFSET;
 211         lc->cpu_nr = cpu;
 212         lc->spinlock_lockval = arch_spin_lockval(cpu);
 213         lc->spinlock_index = 0;
 214         lc->br_r1_trampoline = 0x07f1;  /* br %r1 */
 215         if (nmi_alloc_per_cpu(lc))
 216                 goto out_async;
 217         if (vdso_alloc_per_cpu(lc))
 218                 goto out_mcesa;
 219         lowcore_ptr[cpu] = lc;
 220         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 221         return 0;
 222
 223 out_mcesa:
 224         nmi_free_per_cpu(lc);
 225 out_async:
 226         stack_free(async_stack);
 227 out:
 228         if (pcpu != &pcpu_devices[0]) {
 229                 free_pages(nodat_stack, THREAD_SIZE_ORDER);
 230                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 231         }
 232         return -ENOMEM;
 233 }
 234
 235 static void pcpu_free_lowcore(struct pcpu *pcpu)
 236 {
 237         unsigned long async_stack, nodat_stack, lowcore;
 238
 239         nodat_stack = pcpu->lowcore->nodat_stack - STACK_INIT_OFFSET;
 240         async_stack = pcpu->lowcore->async_stack - STACK_INIT_OFFSET;
 241         lowcore = (unsigned long) pcpu->lowcore;
 242
 243         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 244         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 245         vdso_free_per_cpu(pcpu->lowcore);
 246         nmi_free_per_cpu(pcpu->lowcore);
 247         stack_free(async_stack);
 248         if (pcpu == &pcpu_devices[0])
 249                 return;
 250         free_pages(nodat_stack, THREAD_SIZE_ORDER);
 251         free_pages(lowcore, LC_ORDER);
 252 }
 253
 254 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 255 {
 256         struct lowcore *lc = pcpu->lowcore;
 257
 258         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 259         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 260         lc->cpu_nr = cpu;
 261         lc->spinlock_lockval = arch_spin_lockval(cpu);
 262         lc->spinlock_index = 0;
 263         lc->percpu_offset = __per_cpu_offset[cpu];
 264         lc->kernel_asce = S390_lowcore.kernel_asce;
 265         lc->machine_flags = S390_lowcore.machine_flags;
 266         lc->user_timer = lc->system_timer =
 267                 lc->steal_timer = lc->avg_steal_timer = 0;
 268         __ctl_store(lc->cregs_save_area, 0, 15);
 269         save_access_regs((unsigned int *) lc->access_regs_save_area);
 270         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 271                sizeof(lc->stfle_fac_list));
 272         memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list,
 273                sizeof(lc->alt_stfle_fac_list));
 274         arch_spin_lock_setup(cpu);
 275 }
 276
 277 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 278 {
 279         struct lowcore *lc = pcpu->lowcore;
 280
 281         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 282                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 283         lc->current_task = (unsigned long) tsk;
 284         lc->lpp = LPP_MAGIC;
 285         lc->current_pid = tsk->pid;
 286         lc->user_timer = tsk->thread.user_timer;
 287         lc->guest_timer = tsk->thread.guest_timer;
 288         lc->system_timer = tsk->thread.system_timer;
 289         lc->hardirq_timer = tsk->thread.hardirq_timer;
 290         lc->softirq_timer = tsk->thread.softirq_timer;
 291         lc->steal_timer = 0;
 292 }
 293
 294 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 295 {
 296         struct lowcore *lc = pcpu->lowcore;
 297
 298         lc->restart_stack = lc->nodat_stack;
 299         lc->restart_fn = (unsigned long) func;
 300         lc->restart_data = (unsigned long) data;
 301         lc->restart_source = -1UL;
 302         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 303 }
 304
 305 /*
 306  * Call function via PSW restart on pcpu and stop the current cpu.
 307  */
 308 static void __pcpu_delegate(void (*func)(void*), void *data)
 309 {
 310         func(data);     /* should not return */
 311 }
 312
 313 static void __no_sanitize_address pcpu_delegate(struct pcpu *pcpu,
 314                                                 void (*func)(void *),
 315                                                 void *data, unsigned long stack)
 316 {
 317         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 318         unsigned long source_cpu = stap();
 319
 320         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 321         if (pcpu->address == source_cpu)
 322                 CALL_ON_STACK(__pcpu_delegate, stack, 2, func, data);
 323         /* Stop target cpu (if func returns this stops the current cpu). */
 324         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 325         /* Restart func on the target cpu and stop the current cpu. */
 326         mem_assign_absolute(lc->restart_stack, stack);
 327         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 328         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 329         mem_assign_absolute(lc->restart_source, source_cpu);
 330         __bpon();
 331         asm volatile(
 332                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 333                 "       brc     2,0b    # busy, try again\n"
 334                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 335                 "       brc     2,1b    # busy, try again\n"
 336                 : : "d" (pcpu->address), "d" (source_cpu),
 337                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 338                 : "0", "1", "cc");
 339         for (;;) ;
 340 }
 341
 342 /*
 343  * Enable additional logical cpus for multi-threading.
 344  */
 345 static int pcpu_set_smt(unsigned int mtid)
 346 {
 347         int cc;
 348
 349         if (smp_cpu_mtid == mtid)
 350                 return 0;
 351         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 352         if (cc == 0) {
 353                 smp_cpu_mtid = mtid;
 354                 smp_cpu_mt_shift = 0;
 355                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 356                         smp_cpu_mt_shift++;
 357                 pcpu_devices[0].address = stap();
 358         }
 359         return cc;
 360 }
 361
 362 /*
 363  * Call function on an online CPU.
 364  */
 365 void smp_call_online_cpu(void (*func)(void *), void *data)
 366 {
 367         struct pcpu *pcpu;
 368
 369         /* Use the current cpu if it is online. */
 370         pcpu = pcpu_find_address(cpu_online_mask, stap());
 371         if (!pcpu)
 372                 /* Use the first online cpu. */
 373                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 374         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 375 }
 376
 377 /*
 378  * Call function on the ipl CPU.
 379  */
 380 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 381 {
 382         struct lowcore *lc = pcpu_devices->lowcore;
 383
 384         if (pcpu_devices[0].address == stap())
 385                 lc = &S390_lowcore;
 386
 387         pcpu_delegate(&pcpu_devices[0], func, data,
 388                       lc->nodat_stack);
 389 }
 390
 391 int smp_find_processor_id(u16 address)
 392 {
 393         int cpu;
 394
 395         for_each_present_cpu(cpu)
 396                 if (pcpu_devices[cpu].address == address)
 397                         return cpu;
 398         return -1;
 399 }
 400
 401 bool arch_vcpu_is_preempted(int cpu)
 402 {
 403         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 404                 return false;
 405         if (pcpu_running(pcpu_devices + cpu))
 406                 return false;
 407         return true;
 408 }
 409 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 410
 411 void smp_yield_cpu(int cpu)
 412 {
 413         if (MACHINE_HAS_DIAG9C) {
 414                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 415                 asm volatile("diag %0,0,0x9c"
 416                              : : "d" (pcpu_devices[cpu].address));
 417         } else if (MACHINE_HAS_DIAG44 && !smp_cpu_mtid) {
 418                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 419                 asm volatile("diag 0,0,0x44");
 420         }
 421 }
 422
 423 /*
 424  * Send cpus emergency shutdown signal. This gives the cpus the
 425  * opportunity to complete outstanding interrupts.
 426  */
 427 void notrace smp_emergency_stop(void)
 428 {
 429         cpumask_t cpumask;
 430         u64 end;
 431         int cpu;
 432
 433         cpumask_copy(&cpumask, cpu_online_mask);
 434         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 435
 436         end = get_tod_clock() + (1000000UL << 12);
 437         for_each_cpu(cpu, &cpumask) {
 438                 struct pcpu *pcpu = pcpu_devices + cpu;
 439                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 440                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 441                                    0, NULL) == SIGP_CC_BUSY &&
 442                        get_tod_clock() < end)
 443                         cpu_relax();
 444         }
 445         while (get_tod_clock() < end) {
 446                 for_each_cpu(cpu, &cpumask)
 447                         if (pcpu_stopped(pcpu_devices + cpu))
 448                                 cpumask_clear_cpu(cpu, &cpumask);
 449                 if (cpumask_empty(&cpumask))
 450                         break;
 451                 cpu_relax();
 452         }
 453 }
 454 NOKPROBE_SYMBOL(smp_emergency_stop);
 455
 456 /*
 457  * Stop all cpus but the current one.
 458  */
 459 void smp_send_stop(void)
 460 {
 461         int cpu;
 462
 463         /* Disable all interrupts/machine checks */
 464         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 465         trace_hardirqs_off();
 466
 467         debug_set_critical();
 468
 469         if (oops_in_progress)
 470                 smp_emergency_stop();
 471
 472         /* stop all processors */
 473         for_each_online_cpu(cpu) {
 474                 if (cpu == smp_processor_id())
 475                         continue;
 476                 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
 477                 while (!pcpu_stopped(pcpu_devices + cpu))
 478                         cpu_relax();
 479         }
 480 }
 481
 482 /*
 483  * This is the main routine where commands issued by other
 484  * cpus are handled.
 485  */
 486 static void smp_handle_ext_call(void)
 487 {
 488         unsigned long bits;
 489
 490         /* handle bit signal external calls */
 491         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 492         if (test_bit(ec_stop_cpu, &bits))
 493                 smp_stop_cpu();
 494         if (test_bit(ec_schedule, &bits))
 495                 scheduler_ipi();
 496         if (test_bit(ec_call_function_single, &bits))
 497                 generic_smp_call_function_single_interrupt();
 498 }
 499
 500 static void do_ext_call_interrupt(struct ext_code ext_code,
 501                                   unsigned int param32, unsigned long param64)
 502 {
 503         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 504         smp_handle_ext_call();
 505 }
 506
 507 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 508 {
 509         int cpu;
 510
 511         for_each_cpu(cpu, mask)
 512                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 513 }
 514
 515 void arch_send_call_function_single_ipi(int cpu)
 516 {
 517         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 518 }
 519
 520 /*
 521  * this function sends a 'reschedule' IPI to another CPU.
 522  * it goes straight through and wastes no time serializing
 523  * anything. Worst case is that we lose a reschedule ...
 524  */
 525 void smp_send_reschedule(int cpu)
 526 {
 527         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 528 }
 529
 530 /*
 531  * parameter area for the set/clear control bit callbacks
 532  */
 533 struct ec_creg_mask_parms {
 534         unsigned long orval;
 535         unsigned long andval;
 536         int cr;
 537 };
 538
 539 /*
 540  * callback for setting/clearing control bits
 541  */
 542 static void smp_ctl_bit_callback(void *info)
 543 {
 544         struct ec_creg_mask_parms *pp = info;
 545         unsigned long cregs[16];
 546
 547         __ctl_store(cregs, 0, 15);
 548         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 549         __ctl_load(cregs, 0, 15);
 550 }
 551
 552 /*
 553  * Set a bit in a control register of all cpus
 554  */
 555 void smp_ctl_set_bit(int cr, int bit)
 556 {
 557         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 558
 559         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 560 }
 561 EXPORT_SYMBOL(smp_ctl_set_bit);
 562
 563 /*
 564  * Clear a bit in a control register of all cpus
 565  */
 566 void smp_ctl_clear_bit(int cr, int bit)
 567 {
 568         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 569
 570         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 571 }
 572 EXPORT_SYMBOL(smp_ctl_clear_bit);
 573
 574 #ifdef CONFIG_CRASH_DUMP
 575
 576 int smp_store_status(int cpu)
 577 {
 578         struct pcpu *pcpu = pcpu_devices + cpu;
 579         unsigned long pa;
 580
 581         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 582         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 583                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 584                 return -EIO;
 585         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
 586                 return 0;
 587         pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
 588         if (MACHINE_HAS_GS)
 589                 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
 590         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 591                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 592                 return -EIO;
 593         return 0;
 594 }
 595
 596 /*
 597  * Collect CPU state of the previous, crashed system.
 598  * There are four cases:
 599  * 1) standard zfcp dump
 600  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 601  *    The state for all CPUs except the boot CPU needs to be collected
 602  *    with sigp stop-and-store-status. The boot CPU state is located in
 603  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 604  *    will copy the boot CPU state from the HSA.
 605  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 606  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 607  *    The state for all CPUs except the boot CPU needs to be collected
 608  *    with sigp stop-and-store-status. The firmware or the boot-loader
 609  *    stored the registers of the boot CPU in the absolute lowcore in the
 610  *    memory of the old system.
 611  * 3) kdump and the old kernel did not store the CPU state,
 612  *    or stand-alone kdump for DASD
 613  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 614  *    The state for all CPUs except the boot CPU needs to be collected
 615  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 616  *    stored the registers of the boot CPU in the memory of the old system.
 617  * 4) kdump and the old kernel stored the CPU state
 618  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 619  *    This case does not exist for s390 anymore, setup_arch explicitly
 620  *    deactivates the elfcorehdr= kernel parameter
 621  */
 622 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 623                                      bool is_boot_cpu, unsigned long page)
 624 {
 625         __vector128 *vxrs = (__vector128 *) page;
 626
 627         if (is_boot_cpu)
 628                 vxrs = boot_cpu_vector_save_area;
 629         else
 630                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 631         save_area_add_vxrs(sa, vxrs);
 632 }
 633
 634 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 635                                      bool is_boot_cpu, unsigned long page)
 636 {
 637         void *regs = (void *) page;
 638
 639         if (is_boot_cpu)
 640                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 641         else
 642                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 643         save_area_add_regs(sa, regs);
 644 }
 645
 646 void __init smp_save_dump_cpus(void)
 647 {
 648         int addr, boot_cpu_addr, max_cpu_addr;
 649         struct save_area *sa;
 650         unsigned long page;
 651         bool is_boot_cpu;
 652
 653         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 654                 /* No previous system present, normal boot. */
 655                 return;
 656         /* Allocate a page as dumping area for the store status sigps */
 657         page = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 1UL << 31);
 658         if (!page)
 659                 panic("ERROR: Failed to allocate %lx bytes below %lx\n",
 660                       PAGE_SIZE, 1UL << 31);
 661
 662         /* Set multi-threading state to the previous system. */
 663         pcpu_set_smt(sclp.mtid_prev);
 664         boot_cpu_addr = stap();
 665         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 666         for (addr = 0; addr <= max_cpu_addr; addr++) {
 667                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 668                     SIGP_CC_NOT_OPERATIONAL)
 669                         continue;
 670                 is_boot_cpu = (addr == boot_cpu_addr);
 671                 /* Allocate save area */
 672                 sa = save_area_alloc(is_boot_cpu);
 673                 if (!sa)
 674                         panic("could not allocate memory for save area\n");
 675                 if (MACHINE_HAS_VX)
 676                         /* Get the vector registers */
 677                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 678                 /*
 679                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 680                  * of the boot CPU are stored in the HSA. To retrieve
 681                  * these registers an SCLP request is required which is
 682                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 683                  */
 684                 if (!is_boot_cpu || OLDMEM_BASE)
 685                         /* Get the CPU registers */
 686                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 687         }
 688         memblock_free(page, PAGE_SIZE);
 689         diag_dma_ops.diag308_reset();
 690         pcpu_set_smt(0);
 691 }
 692 #endif /* CONFIG_CRASH_DUMP */
 693
 694 void smp_cpu_set_polarization(int cpu, int val)
 695 {
 696         pcpu_devices[cpu].polarization = val;
 697 }
 698
 699 int smp_cpu_get_polarization(int cpu)
 700 {
 701         return pcpu_devices[cpu].polarization;
 702 }
 703
 704 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 705 {
 706         static int use_sigp_detection;
 707         int address;
 708
 709         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 710                 use_sigp_detection = 1;
 711                 for (address = 0;
 712                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 713                      address += (1U << smp_cpu_mt_shift)) {
 714                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 715                             SIGP_CC_NOT_OPERATIONAL)
 716                                 continue;
 717                         info->core[info->configured].core_id =
 718                                 address >> smp_cpu_mt_shift;
 719                         info->configured++;
 720                 }
 721                 info->combined = info->configured;
 722         }
 723 }
 724
 725 static int smp_add_present_cpu(int cpu);
 726
 727 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 728 {
 729         struct pcpu *pcpu;
 730         cpumask_t avail;
 731         int cpu, nr, i, j;
 732         u16 address;
 733
 734         nr = 0;
 735         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 736         cpu = cpumask_first(&avail);
 737         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 738                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 739                         continue;
 740                 address = info->core[i].core_id << smp_cpu_mt_shift;
 741                 for (j = 0; j <= smp_cpu_mtid; j++) {
 742                         if (pcpu_find_address(cpu_present_mask, address + j))
 743                                 continue;
 744                         pcpu = pcpu_devices + cpu;
 745                         pcpu->address = address + j;
 746                         pcpu->state =
 747                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 748                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 749                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 750                         set_cpu_present(cpu, true);
 751                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 752                                 set_cpu_present(cpu, false);
 753                         else
 754                                 nr++;
 755                         cpu = cpumask_next(cpu, &avail);
 756                         if (cpu >= nr_cpu_ids)
 757                                 break;
 758                 }
 759         }
 760         return nr;
 761 }
 762
 763 void __init smp_detect_cpus(void)
 764 {
 765         unsigned int cpu, mtid, c_cpus, s_cpus;
 766         struct sclp_core_info *info;
 767         u16 address;
 768
 769         /* Get CPU information */
 770         info = memblock_alloc(sizeof(*info), 8);
 771         if (!info)
 772                 panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 773                       __func__, sizeof(*info), 8);
 774         smp_get_core_info(info, 1);
 775         /* Find boot CPU type */
 776         if (sclp.has_core_type) {
 777                 address = stap();
 778                 for (cpu = 0; cpu < info->combined; cpu++)
 779                         if (info->core[cpu].core_id == address) {
 780                                 /* The boot cpu dictates the cpu type. */
 781                                 boot_core_type = info->core[cpu].type;
 782                                 break;
 783                         }
 784                 if (cpu >= info->combined)
 785                         panic("Could not find boot CPU type");
 786         }
 787
 788         /* Set multi-threading state for the current system */
 789         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 790         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 791         pcpu_set_smt(mtid);
 792
 793         /* Print number of CPUs */
 794         c_cpus = s_cpus = 0;
 795         for (cpu = 0; cpu < info->combined; cpu++) {
 796                 if (sclp.has_core_type &&
 797                     info->core[cpu].type != boot_core_type)
 798                         continue;
 799                 if (cpu < info->configured)
 800                         c_cpus += smp_cpu_mtid + 1;
 801                 else
 802                         s_cpus += smp_cpu_mtid + 1;
 803         }
 804         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 805
 806         /* Add CPUs present at boot */
 807         get_online_cpus();
 808         __smp_rescan_cpus(info, 0);
 809         put_online_cpus();
 810         memblock_free_early((unsigned long)info, sizeof(*info));
 811 }
 812
 813 static void smp_init_secondary(void)
 814 {
 815         int cpu = smp_processor_id();
 816
 817         S390_lowcore.last_update_clock = get_tod_clock();
 818         restore_access_regs(S390_lowcore.access_regs_save_area);
 819         cpu_init();
 820         preempt_disable();
 821         init_cpu_timer();
 822         vtime_init();
 823         pfault_init();
 824         notify_cpu_starting(smp_processor_id());
 825         if (topology_cpu_dedicated(cpu))
 826                 set_cpu_flag(CIF_DEDICATED_CPU);
 827         else
 828                 clear_cpu_flag(CIF_DEDICATED_CPU);
 829         set_cpu_online(smp_processor_id(), true);
 830         inc_irq_stat(CPU_RST);
 831         local_irq_enable();
 832         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 833 }
 834
 835 /*
 836  *      Activate a secondary processor.
 837  */
 838 static void __no_sanitize_address smp_start_secondary(void *cpuvoid)
 839 {
 840         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 841         S390_lowcore.restart_fn = (unsigned long) do_restart;
 842         S390_lowcore.restart_data = 0;
 843         S390_lowcore.restart_source = -1UL;
 844         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 845         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 846         CALL_ON_STACK(smp_init_secondary, S390_lowcore.kernel_stack, 0);
 847 }
 848
 849 /* Upping and downing of CPUs */
 850 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 851 {
 852         struct pcpu *pcpu;
 853         int base, i, rc;
 854
 855         pcpu = pcpu_devices + cpu;
 856         if (pcpu->state != CPU_STATE_CONFIGURED)
 857                 return -EIO;
 858         base = smp_get_base_cpu(cpu);
 859         for (i = 0; i <= smp_cpu_mtid; i++) {
 860                 if (base + i < nr_cpu_ids)
 861                         if (cpu_online(base + i))
 862                                 break;
 863         }
 864         /*
 865          * If this is the first CPU of the core to get online
 866          * do an initial CPU reset.
 867          */
 868         if (i > smp_cpu_mtid &&
 869             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 870             SIGP_CC_ORDER_CODE_ACCEPTED)
 871                 return -EIO;
 872
 873         rc = pcpu_alloc_lowcore(pcpu, cpu);
 874         if (rc)
 875                 return rc;
 876         pcpu_prepare_secondary(pcpu, cpu);
 877         pcpu_attach_task(pcpu, tidle);
 878         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 879         /* Wait until cpu puts itself in the online & active maps */
 880         while (!cpu_online(cpu))
 881                 cpu_relax();
 882         return 0;
 883 }
 884
 885 static unsigned int setup_possible_cpus __initdata;
 886
 887 static int __init _setup_possible_cpus(char *s)
 888 {
 889         get_option(&s, &setup_possible_cpus);
 890         return 0;
 891 }
 892 early_param("possible_cpus", _setup_possible_cpus);
 893
 894 int __cpu_disable(void)
 895 {
 896         unsigned long cregs[16];
 897
 898         /* Handle possible pending IPIs */
 899         smp_handle_ext_call();
 900         set_cpu_online(smp_processor_id(), false);
 901         /* Disable pseudo page faults on this cpu. */
 902         pfault_fini();
 903         /* Disable interrupt sources via control register. */
 904         __ctl_store(cregs, 0, 15);
 905         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 906         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 907         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 908         __ctl_load(cregs, 0, 15);
 909         clear_cpu_flag(CIF_NOHZ_DELAY);
 910         return 0;
 911 }
 912
 913 void __cpu_die(unsigned int cpu)
 914 {
 915         struct pcpu *pcpu;
 916
 917         /* Wait until target cpu is down */
 918         pcpu = pcpu_devices + cpu;
 919         while (!pcpu_stopped(pcpu))
 920                 cpu_relax();
 921         pcpu_free_lowcore(pcpu);
 922         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 923         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 924 }
 925
 926 void __noreturn cpu_die(void)
 927 {
 928         idle_task_exit();
 929         __bpon();
 930         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 931         for (;;) ;
 932 }
 933
 934 void __init smp_fill_possible_mask(void)
 935 {
 936         unsigned int possible, sclp_max, cpu;
 937
 938         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 939         sclp_max = min(smp_max_threads, sclp_max);
 940         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 941         possible = setup_possible_cpus ?: nr_cpu_ids;
 942         possible = min(possible, sclp_max);
 943         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 944                 set_cpu_possible(cpu, true);
 945 }
 946
 947 void __init smp_prepare_cpus(unsigned int max_cpus)
 948 {
 949         /* request the 0x1201 emergency signal external interrupt */
 950         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 951                 panic("Couldn't request external interrupt 0x1201");
 952         /* request the 0x1202 external call external interrupt */
 953         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 954                 panic("Couldn't request external interrupt 0x1202");
 955 }
 956
 957 void __init smp_prepare_boot_cpu(void)
 958 {
 959         struct pcpu *pcpu = pcpu_devices;
 960
 961         WARN_ON(!cpu_present(0) || !cpu_online(0));
 962         pcpu->state = CPU_STATE_CONFIGURED;
 963         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 964         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 965         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 966 }
 967
 968 void __init smp_cpus_done(unsigned int max_cpus)
 969 {
 970 }
 971
 972 void __init smp_setup_processor_id(void)
 973 {
 974         pcpu_devices[0].address = stap();
 975         S390_lowcore.cpu_nr = 0;
 976         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 977         S390_lowcore.spinlock_index = 0;
 978 }
 979
 980 /*
 981  * the frequency of the profiling timer can be changed
 982  * by writing a multiplier value into /proc/profile.
 983  *
 984  * usually you want to run this on all CPUs ;)
 985  */
 986 int setup_profiling_timer(unsigned int multiplier)
 987 {
 988         return 0;
 989 }
 990
 991 static ssize_t cpu_configure_show(struct device *dev,
 992                                   struct device_attribute *attr, char *buf)
 993 {
 994         ssize_t count;
 995
 996         mutex_lock(&smp_cpu_state_mutex);
 997         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 998         mutex_unlock(&smp_cpu_state_mutex);
 999         return count;
1000 }
1001
1002 static ssize_t cpu_configure_store(struct device *dev,
1003                                    struct device_attribute *attr,
1004                                    const char *buf, size_t count)
1005 {
1006         struct pcpu *pcpu;
1007         int cpu, val, rc, i;
1008         char delim;
1009
1010         if (sscanf(buf, "%d %c", &val, &delim) != 1)
1011                 return -EINVAL;
1012         if (val != 0 && val != 1)
1013                 return -EINVAL;
1014         get_online_cpus();
1015         mutex_lock(&smp_cpu_state_mutex);
1016         rc = -EBUSY;
1017         /* disallow configuration changes of online cpus and cpu 0 */
1018         cpu = dev->id;
1019         cpu = smp_get_base_cpu(cpu);
1020         if (cpu == 0)
1021                 goto out;
1022         for (i = 0; i <= smp_cpu_mtid; i++)
1023                 if (cpu_online(cpu + i))
1024                         goto out;
1025         pcpu = pcpu_devices + cpu;
1026         rc = 0;
1027         switch (val) {
1028         case 0:
1029                 if (pcpu->state != CPU_STATE_CONFIGURED)
1030                         break;
1031                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1032                 if (rc)
1033                         break;
1034                 for (i = 0; i <= smp_cpu_mtid; i++) {
1035                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1036                                 continue;
1037                         pcpu[i].state = CPU_STATE_STANDBY;
1038                         smp_cpu_set_polarization(cpu + i,
1039                                                  POLARIZATION_UNKNOWN);
1040                 }
1041                 topology_expect_change();
1042                 break;
1043         case 1:
1044                 if (pcpu->state != CPU_STATE_STANDBY)
1045                         break;
1046                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1047                 if (rc)
1048                         break;
1049                 for (i = 0; i <= smp_cpu_mtid; i++) {
1050                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1051                                 continue;
1052                         pcpu[i].state = CPU_STATE_CONFIGURED;
1053                         smp_cpu_set_polarization(cpu + i,
1054                                                  POLARIZATION_UNKNOWN);
1055                 }
1056                 topology_expect_change();
1057                 break;
1058         default:
1059                 break;
1060         }
1061 out:
1062         mutex_unlock(&smp_cpu_state_mutex);
1063         put_online_cpus();
1064         return rc ? rc : count;
1065 }
1066 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1067
1068 static ssize_t show_cpu_address(struct device *dev,
1069                                 struct device_attribute *attr, char *buf)
1070 {
1071         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1072 }
1073 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1074
1075 static struct attribute *cpu_common_attrs[] = {
1076         &dev_attr_configure.attr,
1077         &dev_attr_address.attr,
1078         NULL,
1079 };
1080
1081 static struct attribute_group cpu_common_attr_group = {
1082         .attrs = cpu_common_attrs,
1083 };
1084
1085 static struct attribute *cpu_online_attrs[] = {
1086         &dev_attr_idle_count.attr,
1087         &dev_attr_idle_time_us.attr,
1088         NULL,
1089 };
1090
1091 static struct attribute_group cpu_online_attr_group = {
1092         .attrs = cpu_online_attrs,
1093 };
1094
1095 static int smp_cpu_online(unsigned int cpu)
1096 {
1097         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1098
1099         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1100 }
1101 static int smp_cpu_pre_down(unsigned int cpu)
1102 {
1103         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1104
1105         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1106         return 0;
1107 }
1108
1109 static int smp_add_present_cpu(int cpu)
1110 {
1111         struct device *s;
1112         struct cpu *c;
1113         int rc;
1114
1115         c = kzalloc(sizeof(*c), GFP_KERNEL);
1116         if (!c)
1117                 return -ENOMEM;
1118         per_cpu(cpu_device, cpu) = c;
1119         s = &c->dev;
1120         c->hotpluggable = 1;
1121         rc = register_cpu(c, cpu);
1122         if (rc)
1123                 goto out;
1124         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1125         if (rc)
1126                 goto out_cpu;
1127         rc = topology_cpu_init(c);
1128         if (rc)
1129                 goto out_topology;
1130         return 0;
1131
1132 out_topology:
1133         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1134 out_cpu:
1135         unregister_cpu(c);
1136 out:
1137         return rc;
1138 }
1139
1140 int __ref smp_rescan_cpus(void)
1141 {
1142         struct sclp_core_info *info;
1143         int nr;
1144
1145         info = kzalloc(sizeof(*info), GFP_KERNEL);
1146         if (!info)
1147                 return -ENOMEM;
1148         smp_get_core_info(info, 0);
1149         get_online_cpus();
1150         mutex_lock(&smp_cpu_state_mutex);
1151         nr = __smp_rescan_cpus(info, 1);
1152         mutex_unlock(&smp_cpu_state_mutex);
1153         put_online_cpus();
1154         kfree(info);
1155         if (nr)
1156                 topology_schedule_update();
1157         return 0;
1158 }
1159
1160 static ssize_t __ref rescan_store(struct device *dev,
1161                                   struct device_attribute *attr,
1162                                   const char *buf,
1163                                   size_t count)
1164 {
1165         int rc;
1166
1167         rc = lock_device_hotplug_sysfs();
1168         if (rc)
1169                 return rc;
1170         rc = smp_rescan_cpus();
1171         unlock_device_hotplug();
1172         return rc ? rc : count;
1173 }
1174 static DEVICE_ATTR_WO(rescan);
1175
1176 static int __init s390_smp_init(void)
1177 {
1178         int cpu, rc = 0;
1179
1180         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1181         if (rc)
1182                 return rc;
1183         for_each_present_cpu(cpu) {
1184                 rc = smp_add_present_cpu(cpu);
1185                 if (rc)
1186                         goto out;
1187         }
1188
1189         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1190                                smp_cpu_online, smp_cpu_pre_down);
1191         rc = rc <= 0 ? rc : 0;
1192 out:
1193         return rc;
1194 }
1195 subsys_initcall(s390_smp_init);