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/irq_work.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/kprobes.h>
  40 #include <asm/asm-offsets.h>
  41 #include <asm/diag.h>
  42 #include <asm/switch_to.h>
  43 #include <asm/facility.h>
  44 #include <asm/ipl.h>
  45 #include <asm/setup.h>
  46 #include <asm/irq.h>
  47 #include <asm/tlbflush.h>
  48 #include <asm/vtimer.h>
  49 #include <asm/lowcore.h>
  50 #include <asm/sclp.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 <asm/vdso.h>
  59 #include "entry.h"
  60
  61 enum {
  62         ec_schedule = 0,
  63         ec_call_function_single,
  64         ec_stop_cpu,
  65         ec_mcck_pending,
  66         ec_irq_work,
  67 };
  68
  69 enum {
  70         CPU_STATE_STANDBY,
  71         CPU_STATE_CONFIGURED,
  72 };
  73
  74 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  75
  76 struct pcpu {
  77         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  78         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  79         signed char state;              /* physical cpu state */
  80         signed char polarization;       /* physical polarization */
  81         u16 address;                    /* physical cpu address */
  82 };
  83
  84 static u8 boot_core_type;
  85 static struct pcpu pcpu_devices[NR_CPUS];
  86
  87 unsigned int smp_cpu_mt_shift;
  88 EXPORT_SYMBOL(smp_cpu_mt_shift);
  89
  90 unsigned int smp_cpu_mtid;
  91 EXPORT_SYMBOL(smp_cpu_mtid);
  92
  93 #ifdef CONFIG_CRASH_DUMP
  94 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  95 #endif
  96
  97 static unsigned int smp_max_threads __initdata = -1U;
  98
  99 static int __init early_nosmt(char *s)
 100 {
 101         smp_max_threads = 1;
 102         return 0;
 103 }
 104 early_param("nosmt", early_nosmt);
 105
 106 static int __init early_smt(char *s)
 107 {
 108         get_option(&s, &smp_max_threads);
 109         return 0;
 110 }
 111 early_param("smt", early_smt);
 112
 113 /*
 114  * The smp_cpu_state_mutex must be held when changing the state or polarization
 115  * member of a pcpu data structure within the pcpu_devices arreay.
 116  */
 117 DEFINE_MUTEX(smp_cpu_state_mutex);
 118
 119 /*
 120  * Signal processor helper functions.
 121  */
 122 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 123 {
 124         int cc;
 125
 126         while (1) {
 127                 cc = __pcpu_sigp(addr, order, parm, NULL);
 128                 if (cc != SIGP_CC_BUSY)
 129                         return cc;
 130                 cpu_relax();
 131         }
 132 }
 133
 134 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 135 {
 136         int cc, retry;
 137
 138         for (retry = 0; ; retry++) {
 139                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 140                 if (cc != SIGP_CC_BUSY)
 141                         break;
 142                 if (retry >= 3)
 143                         udelay(10);
 144         }
 145         return cc;
 146 }
 147
 148 static inline int pcpu_stopped(struct pcpu *pcpu)
 149 {
 150         u32 status;
 151
 152         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 153                         0, &status) != SIGP_CC_STATUS_STORED)
 154                 return 0;
 155         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 156 }
 157
 158 static inline int pcpu_running(struct pcpu *pcpu)
 159 {
 160         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 161                         0, NULL) != SIGP_CC_STATUS_STORED)
 162                 return 1;
 163         /* Status stored condition code is equivalent to cpu not running. */
 164         return 0;
 165 }
 166
 167 /*
 168  * Find struct pcpu by cpu address.
 169  */
 170 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 171 {
 172         int cpu;
 173
 174         for_each_cpu(cpu, mask)
 175                 if (pcpu_devices[cpu].address == address)
 176                         return pcpu_devices + cpu;
 177         return NULL;
 178 }
 179
 180 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 181 {
 182         int order;
 183
 184         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 185                 return;
 186         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 187         pcpu->ec_clk = get_tod_clock_fast();
 188         pcpu_sigp_retry(pcpu, order, 0);
 189 }
 190
 191 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 192 {
 193         unsigned long async_stack, nodat_stack, mcck_stack;
 194         struct lowcore *lc;
 195
 196         lc = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 197         nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
 198         async_stack = stack_alloc();
 199         mcck_stack = stack_alloc();
 200         if (!lc || !nodat_stack || !async_stack || !mcck_stack)
 201                 goto out;
 202         memcpy(lc, &S390_lowcore, 512);
 203         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 204         lc->async_stack = async_stack + STACK_INIT_OFFSET;
 205         lc->nodat_stack = nodat_stack + STACK_INIT_OFFSET;
 206         lc->mcck_stack = mcck_stack + STACK_INIT_OFFSET;
 207         lc->cpu_nr = cpu;
 208         lc->spinlock_lockval = arch_spin_lockval(cpu);
 209         lc->spinlock_index = 0;
 210         lc->br_r1_trampoline = 0x07f1;  /* br %r1 */
 211         lc->return_lpswe = gen_lpswe(__LC_RETURN_PSW);
 212         lc->return_mcck_lpswe = gen_lpswe(__LC_RETURN_MCCK_PSW);
 213         if (nmi_alloc_per_cpu(lc))
 214                 goto out;
 215         lowcore_ptr[cpu] = lc;
 216         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 217         return 0;
 218
 219 out:
 220         stack_free(mcck_stack);
 221         stack_free(async_stack);
 222         free_pages(nodat_stack, THREAD_SIZE_ORDER);
 223         free_pages((unsigned long) lc, LC_ORDER);
 224         return -ENOMEM;
 225 }
 226
 227 static void pcpu_free_lowcore(struct pcpu *pcpu)
 228 {
 229         unsigned long async_stack, nodat_stack, mcck_stack;
 230         struct lowcore *lc;
 231         int cpu;
 232
 233         cpu = pcpu - pcpu_devices;
 234         lc = lowcore_ptr[cpu];
 235         nodat_stack = lc->nodat_stack - STACK_INIT_OFFSET;
 236         async_stack = lc->async_stack - STACK_INIT_OFFSET;
 237         mcck_stack = lc->mcck_stack - STACK_INIT_OFFSET;
 238         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 239         lowcore_ptr[cpu] = NULL;
 240         nmi_free_per_cpu(lc);
 241         stack_free(async_stack);
 242         stack_free(mcck_stack);
 243         free_pages(nodat_stack, THREAD_SIZE_ORDER);
 244         free_pages((unsigned long) lc, LC_ORDER);
 245 }
 246
 247 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 248 {
 249         struct lowcore *lc = lowcore_ptr[cpu];
 250
 251         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 252         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 253         lc->cpu_nr = cpu;
 254         lc->spinlock_lockval = arch_spin_lockval(cpu);
 255         lc->spinlock_index = 0;
 256         lc->percpu_offset = __per_cpu_offset[cpu];
 257         lc->kernel_asce = S390_lowcore.kernel_asce;
 258         lc->user_asce = s390_invalid_asce;
 259         lc->machine_flags = S390_lowcore.machine_flags;
 260         lc->user_timer = lc->system_timer =
 261                 lc->steal_timer = lc->avg_steal_timer = 0;
 262         __ctl_store(lc->cregs_save_area, 0, 15);
 263         lc->cregs_save_area[1] = lc->kernel_asce;
 264         lc->cregs_save_area[7] = lc->user_asce;
 265         save_access_regs((unsigned int *) lc->access_regs_save_area);
 266         arch_spin_lock_setup(cpu);
 267 }
 268
 269 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 270 {
 271         struct lowcore *lc;
 272         int cpu;
 273
 274         cpu = pcpu - pcpu_devices;
 275         lc = lowcore_ptr[cpu];
 276         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 277                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 278         lc->current_task = (unsigned long) tsk;
 279         lc->lpp = LPP_MAGIC;
 280         lc->current_pid = tsk->pid;
 281         lc->user_timer = tsk->thread.user_timer;
 282         lc->guest_timer = tsk->thread.guest_timer;
 283         lc->system_timer = tsk->thread.system_timer;
 284         lc->hardirq_timer = tsk->thread.hardirq_timer;
 285         lc->softirq_timer = tsk->thread.softirq_timer;
 286         lc->steal_timer = 0;
 287 }
 288
 289 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 290 {
 291         struct lowcore *lc;
 292         int cpu;
 293
 294         cpu = pcpu - pcpu_devices;
 295         lc = lowcore_ptr[cpu];
 296         lc->restart_stack = lc->nodat_stack;
 297         lc->restart_fn = (unsigned long) func;
 298         lc->restart_data = (unsigned long) data;
 299         lc->restart_source = -1UL;
 300         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 301 }
 302
 303 /*
 304  * Call function via PSW restart on pcpu and stop the current cpu.
 305  */
 306 static void __pcpu_delegate(void (*func)(void*), void *data)
 307 {
 308         func(data);     /* should not return */
 309 }
 310
 311 static void __no_sanitize_address pcpu_delegate(struct pcpu *pcpu,
 312                                                 void (*func)(void *),
 313                                                 void *data, unsigned long stack)
 314 {
 315         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 316         unsigned long source_cpu = stap();
 317
 318         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 319         if (pcpu->address == source_cpu)
 320                 CALL_ON_STACK(__pcpu_delegate, stack, 2, func, data);
 321         /* Stop target cpu (if func returns this stops the current cpu). */
 322         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 323         /* Restart func on the target cpu and stop the current cpu. */
 324         mem_assign_absolute(lc->restart_stack, stack);
 325         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 326         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 327         mem_assign_absolute(lc->restart_source, source_cpu);
 328         __bpon();
 329         asm volatile(
 330                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 331                 "       brc     2,0b    # busy, try again\n"
 332                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 333                 "       brc     2,1b    # busy, try again\n"
 334                 : : "d" (pcpu->address), "d" (source_cpu),
 335                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 336                 : "0", "1", "cc");
 337         for (;;) ;
 338 }
 339
 340 /*
 341  * Enable additional logical cpus for multi-threading.
 342  */
 343 static int pcpu_set_smt(unsigned int mtid)
 344 {
 345         int cc;
 346
 347         if (smp_cpu_mtid == mtid)
 348                 return 0;
 349         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 350         if (cc == 0) {
 351                 smp_cpu_mtid = mtid;
 352                 smp_cpu_mt_shift = 0;
 353                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 354                         smp_cpu_mt_shift++;
 355                 pcpu_devices[0].address = stap();
 356         }
 357         return cc;
 358 }
 359
 360 /*
 361  * Call function on an online CPU.
 362  */
 363 void smp_call_online_cpu(void (*func)(void *), void *data)
 364 {
 365         struct pcpu *pcpu;
 366
 367         /* Use the current cpu if it is online. */
 368         pcpu = pcpu_find_address(cpu_online_mask, stap());
 369         if (!pcpu)
 370                 /* Use the first online cpu. */
 371                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 372         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 373 }
 374
 375 /*
 376  * Call function on the ipl CPU.
 377  */
 378 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 379 {
 380         struct lowcore *lc = lowcore_ptr[0];
 381
 382         if (pcpu_devices[0].address == stap())
 383                 lc = &S390_lowcore;
 384
 385         pcpu_delegate(&pcpu_devices[0], func, data,
 386                       lc->nodat_stack);
 387 }
 388
 389 int smp_find_processor_id(u16 address)
 390 {
 391         int cpu;
 392
 393         for_each_present_cpu(cpu)
 394                 if (pcpu_devices[cpu].address == address)
 395                         return cpu;
 396         return -1;
 397 }
 398
 399 void schedule_mcck_handler(void)
 400 {
 401         pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_mcck_pending);
 402 }
 403
 404 bool notrace arch_vcpu_is_preempted(int cpu)
 405 {
 406         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 407                 return false;
 408         if (pcpu_running(pcpu_devices + cpu))
 409                 return false;
 410         return true;
 411 }
 412 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 413
 414 void notrace smp_yield_cpu(int cpu)
 415 {
 416         if (!MACHINE_HAS_DIAG9C)
 417                 return;
 418         diag_stat_inc_norecursion(DIAG_STAT_X09C);
 419         asm volatile("diag %0,0,0x9c"
 420                      : : "d" (pcpu_devices[cpu].address));
 421 }
 422 EXPORT_SYMBOL_GPL(smp_yield_cpu);
 423
 424 /*
 425  * Send cpus emergency shutdown signal. This gives the cpus the
 426  * opportunity to complete outstanding interrupts.
 427  */
 428 void notrace smp_emergency_stop(void)
 429 {
 430         static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
 431         static cpumask_t cpumask;
 432         u64 end;
 433         int cpu;
 434
 435         arch_spin_lock(&lock);
 436         cpumask_copy(&cpumask, cpu_online_mask);
 437         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 438
 439         end = get_tod_clock() + (1000000UL << 12);
 440         for_each_cpu(cpu, &cpumask) {
 441                 struct pcpu *pcpu = pcpu_devices + cpu;
 442                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 443                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 444                                    0, NULL) == SIGP_CC_BUSY &&
 445                        get_tod_clock() < end)
 446                         cpu_relax();
 447         }
 448         while (get_tod_clock() < end) {
 449                 for_each_cpu(cpu, &cpumask)
 450                         if (pcpu_stopped(pcpu_devices + cpu))
 451                                 cpumask_clear_cpu(cpu, &cpumask);
 452                 if (cpumask_empty(&cpumask))
 453                         break;
 454                 cpu_relax();
 455         }
 456         arch_spin_unlock(&lock);
 457 }
 458 NOKPROBE_SYMBOL(smp_emergency_stop);
 459
 460 /*
 461  * Stop all cpus but the current one.
 462  */
 463 void smp_send_stop(void)
 464 {
 465         int cpu;
 466
 467         /* Disable all interrupts/machine checks */
 468         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 469         trace_hardirqs_off();
 470
 471         debug_set_critical();
 472
 473         if (oops_in_progress)
 474                 smp_emergency_stop();
 475
 476         /* stop all processors */
 477         for_each_online_cpu(cpu) {
 478                 if (cpu == smp_processor_id())
 479                         continue;
 480                 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
 481                 while (!pcpu_stopped(pcpu_devices + cpu))
 482                         cpu_relax();
 483         }
 484 }
 485
 486 /*
 487  * This is the main routine where commands issued by other
 488  * cpus are handled.
 489  */
 490 static void smp_handle_ext_call(void)
 491 {
 492         unsigned long bits;
 493
 494         /* handle bit signal external calls */
 495         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 496         if (test_bit(ec_stop_cpu, &bits))
 497                 smp_stop_cpu();
 498         if (test_bit(ec_schedule, &bits))
 499                 scheduler_ipi();
 500         if (test_bit(ec_call_function_single, &bits))
 501                 generic_smp_call_function_single_interrupt();
 502         if (test_bit(ec_mcck_pending, &bits))
 503                 __s390_handle_mcck();
 504         if (test_bit(ec_irq_work, &bits))
 505                 irq_work_run();
 506 }
 507
 508 static void do_ext_call_interrupt(struct ext_code ext_code,
 509                                   unsigned int param32, unsigned long param64)
 510 {
 511         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 512         smp_handle_ext_call();
 513 }
 514
 515 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 516 {
 517         int cpu;
 518
 519         for_each_cpu(cpu, mask)
 520                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 521 }
 522
 523 void arch_send_call_function_single_ipi(int cpu)
 524 {
 525         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 526 }
 527
 528 /*
 529  * this function sends a 'reschedule' IPI to another CPU.
 530  * it goes straight through and wastes no time serializing
 531  * anything. Worst case is that we lose a reschedule ...
 532  */
 533 void smp_send_reschedule(int cpu)
 534 {
 535         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 536 }
 537
 538 #ifdef CONFIG_IRQ_WORK
 539 void arch_irq_work_raise(void)
 540 {
 541         pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_irq_work);
 542 }
 543 #endif
 544
 545 /*
 546  * parameter area for the set/clear control bit callbacks
 547  */
 548 struct ec_creg_mask_parms {
 549         unsigned long orval;
 550         unsigned long andval;
 551         int cr;
 552 };
 553
 554 /*
 555  * callback for setting/clearing control bits
 556  */
 557 static void smp_ctl_bit_callback(void *info)
 558 {
 559         struct ec_creg_mask_parms *pp = info;
 560         unsigned long cregs[16];
 561
 562         __ctl_store(cregs, 0, 15);
 563         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 564         __ctl_load(cregs, 0, 15);
 565 }
 566
 567 /*
 568  * Set a bit in a control register of all cpus
 569  */
 570 void smp_ctl_set_bit(int cr, int bit)
 571 {
 572         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 573
 574         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 575 }
 576 EXPORT_SYMBOL(smp_ctl_set_bit);
 577
 578 /*
 579  * Clear a bit in a control register of all cpus
 580  */
 581 void smp_ctl_clear_bit(int cr, int bit)
 582 {
 583         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 584
 585         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 586 }
 587 EXPORT_SYMBOL(smp_ctl_clear_bit);
 588
 589 #ifdef CONFIG_CRASH_DUMP
 590
 591 int smp_store_status(int cpu)
 592 {
 593         struct lowcore *lc;
 594         struct pcpu *pcpu;
 595         unsigned long pa;
 596
 597         pcpu = pcpu_devices + cpu;
 598         lc = lowcore_ptr[cpu];
 599         pa = __pa(&lc->floating_pt_save_area);
 600         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 601                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 602                 return -EIO;
 603         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
 604                 return 0;
 605         pa = __pa(lc->mcesad & MCESA_ORIGIN_MASK);
 606         if (MACHINE_HAS_GS)
 607                 pa |= lc->mcesad & MCESA_LC_MASK;
 608         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 609                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 610                 return -EIO;
 611         return 0;
 612 }
 613
 614 /*
 615  * Collect CPU state of the previous, crashed system.
 616  * There are four cases:
 617  * 1) standard zfcp/nvme dump
 618  *    condition: OLDMEM_BASE == NULL && is_ipl_type_dump() == true
 619  *    The state for all CPUs except the boot CPU needs to be collected
 620  *    with sigp stop-and-store-status. The boot CPU state is located in
 621  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 622  *    will copy the boot CPU state from the HSA.
 623  * 2) stand-alone kdump for SCSI/NVMe (zfcp/nvme dump with swapped memory)
 624  *    condition: OLDMEM_BASE != NULL && is_ipl_type_dump() == true
 625  *    The state for all CPUs except the boot CPU needs to be collected
 626  *    with sigp stop-and-store-status. The firmware or the boot-loader
 627  *    stored the registers of the boot CPU in the absolute lowcore in the
 628  *    memory of the old system.
 629  * 3) kdump and the old kernel did not store the CPU state,
 630  *    or stand-alone kdump for DASD
 631  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 632  *    The state for all CPUs except the boot CPU needs to be collected
 633  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 634  *    stored the registers of the boot CPU in the memory of the old system.
 635  * 4) kdump and the old kernel stored the CPU state
 636  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 637  *    This case does not exist for s390 anymore, setup_arch explicitly
 638  *    deactivates the elfcorehdr= kernel parameter
 639  */
 640 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 641                                      bool is_boot_cpu, unsigned long page)
 642 {
 643         __vector128 *vxrs = (__vector128 *) page;
 644
 645         if (is_boot_cpu)
 646                 vxrs = boot_cpu_vector_save_area;
 647         else
 648                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 649         save_area_add_vxrs(sa, vxrs);
 650 }
 651
 652 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 653                                      bool is_boot_cpu, unsigned long page)
 654 {
 655         void *regs = (void *) page;
 656
 657         if (is_boot_cpu)
 658                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 659         else
 660                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 661         save_area_add_regs(sa, regs);
 662 }
 663
 664 void __init smp_save_dump_cpus(void)
 665 {
 666         int addr, boot_cpu_addr, max_cpu_addr;
 667         struct save_area *sa;
 668         unsigned long page;
 669         bool is_boot_cpu;
 670
 671         if (!(OLDMEM_BASE || is_ipl_type_dump()))
 672                 /* No previous system present, normal boot. */
 673                 return;
 674         /* Allocate a page as dumping area for the store status sigps */
 675         page = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 1UL << 31);
 676         if (!page)
 677                 panic("ERROR: Failed to allocate %lx bytes below %lx\n",
 678                       PAGE_SIZE, 1UL << 31);
 679
 680         /* Set multi-threading state to the previous system. */
 681         pcpu_set_smt(sclp.mtid_prev);
 682         boot_cpu_addr = stap();
 683         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 684         for (addr = 0; addr <= max_cpu_addr; addr++) {
 685                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 686                     SIGP_CC_NOT_OPERATIONAL)
 687                         continue;
 688                 is_boot_cpu = (addr == boot_cpu_addr);
 689                 /* Allocate save area */
 690                 sa = save_area_alloc(is_boot_cpu);
 691                 if (!sa)
 692                         panic("could not allocate memory for save area\n");
 693                 if (MACHINE_HAS_VX)
 694                         /* Get the vector registers */
 695                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 696                 /*
 697                  * For a zfcp/nvme dump OLDMEM_BASE == NULL and the registers
 698                  * of the boot CPU are stored in the HSA. To retrieve
 699                  * these registers an SCLP request is required which is
 700                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 701                  */
 702                 if (!is_boot_cpu || OLDMEM_BASE)
 703                         /* Get the CPU registers */
 704                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 705         }
 706         memblock_free(page, PAGE_SIZE);
 707         diag_dma_ops.diag308_reset();
 708         pcpu_set_smt(0);
 709 }
 710 #endif /* CONFIG_CRASH_DUMP */
 711
 712 void smp_cpu_set_polarization(int cpu, int val)
 713 {
 714         pcpu_devices[cpu].polarization = val;
 715 }
 716
 717 int smp_cpu_get_polarization(int cpu)
 718 {
 719         return pcpu_devices[cpu].polarization;
 720 }
 721
 722 int smp_cpu_get_cpu_address(int cpu)
 723 {
 724         return pcpu_devices[cpu].address;
 725 }
 726
 727 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 728 {
 729         static int use_sigp_detection;
 730         int address;
 731
 732         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 733                 use_sigp_detection = 1;
 734                 for (address = 0;
 735                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 736                      address += (1U << smp_cpu_mt_shift)) {
 737                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 738                             SIGP_CC_NOT_OPERATIONAL)
 739                                 continue;
 740                         info->core[info->configured].core_id =
 741                                 address >> smp_cpu_mt_shift;
 742                         info->configured++;
 743                 }
 744                 info->combined = info->configured;
 745         }
 746 }
 747
 748 static int smp_add_present_cpu(int cpu);
 749
 750 static int smp_add_core(struct sclp_core_entry *core, cpumask_t *avail,
 751                         bool configured, bool early)
 752 {
 753         struct pcpu *pcpu;
 754         int cpu, nr, i;
 755         u16 address;
 756
 757         nr = 0;
 758         if (sclp.has_core_type && core->type != boot_core_type)
 759                 return nr;
 760         cpu = cpumask_first(avail);
 761         address = core->core_id << smp_cpu_mt_shift;
 762         for (i = 0; (i <= smp_cpu_mtid) && (cpu < nr_cpu_ids); i++) {
 763                 if (pcpu_find_address(cpu_present_mask, address + i))
 764                         continue;
 765                 pcpu = pcpu_devices + cpu;
 766                 pcpu->address = address + i;
 767                 if (configured)
 768                         pcpu->state = CPU_STATE_CONFIGURED;
 769                 else
 770                         pcpu->state = CPU_STATE_STANDBY;
 771                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 772                 set_cpu_present(cpu, true);
 773                 if (!early && smp_add_present_cpu(cpu) != 0)
 774                         set_cpu_present(cpu, false);
 775                 else
 776                         nr++;
 777                 cpumask_clear_cpu(cpu, avail);
 778                 cpu = cpumask_next(cpu, avail);
 779         }
 780         return nr;
 781 }
 782
 783 static int __smp_rescan_cpus(struct sclp_core_info *info, bool early)
 784 {
 785         struct sclp_core_entry *core;
 786         static cpumask_t avail;
 787         bool configured;
 788         u16 core_id;
 789         int nr, i;
 790
 791         get_online_cpus();
 792         mutex_lock(&smp_cpu_state_mutex);
 793         nr = 0;
 794         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 795         /*
 796          * Add IPL core first (which got logical CPU number 0) to make sure
 797          * that all SMT threads get subsequent logical CPU numbers.
 798          */
 799         if (early) {
 800                 core_id = pcpu_devices[0].address >> smp_cpu_mt_shift;
 801                 for (i = 0; i < info->configured; i++) {
 802                         core = &info->core[i];
 803                         if (core->core_id == core_id) {
 804                                 nr += smp_add_core(core, &avail, true, early);
 805                                 break;
 806                         }
 807                 }
 808         }
 809         for (i = 0; i < info->combined; i++) {
 810                 configured = i < info->configured;
 811                 nr += smp_add_core(&info->core[i], &avail, configured, early);
 812         }
 813         mutex_unlock(&smp_cpu_state_mutex);
 814         put_online_cpus();
 815         return nr;
 816 }
 817
 818 void __init smp_detect_cpus(void)
 819 {
 820         unsigned int cpu, mtid, c_cpus, s_cpus;
 821         struct sclp_core_info *info;
 822         u16 address;
 823
 824         /* Get CPU information */
 825         info = memblock_alloc(sizeof(*info), 8);
 826         if (!info)
 827                 panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 828                       __func__, sizeof(*info), 8);
 829         smp_get_core_info(info, 1);
 830         /* Find boot CPU type */
 831         if (sclp.has_core_type) {
 832                 address = stap();
 833                 for (cpu = 0; cpu < info->combined; cpu++)
 834                         if (info->core[cpu].core_id == address) {
 835                                 /* The boot cpu dictates the cpu type. */
 836                                 boot_core_type = info->core[cpu].type;
 837                                 break;
 838                         }
 839                 if (cpu >= info->combined)
 840                         panic("Could not find boot CPU type");
 841         }
 842
 843         /* Set multi-threading state for the current system */
 844         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 845         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 846         pcpu_set_smt(mtid);
 847
 848         /* Print number of CPUs */
 849         c_cpus = s_cpus = 0;
 850         for (cpu = 0; cpu < info->combined; cpu++) {
 851                 if (sclp.has_core_type &&
 852                     info->core[cpu].type != boot_core_type)
 853                         continue;
 854                 if (cpu < info->configured)
 855                         c_cpus += smp_cpu_mtid + 1;
 856                 else
 857                         s_cpus += smp_cpu_mtid + 1;
 858         }
 859         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 860
 861         /* Add CPUs present at boot */
 862         __smp_rescan_cpus(info, true);
 863         memblock_free_early((unsigned long)info, sizeof(*info));
 864 }
 865
 866 static void smp_init_secondary(void)
 867 {
 868         int cpu = raw_smp_processor_id();
 869
 870         S390_lowcore.last_update_clock = get_tod_clock();
 871         restore_access_regs(S390_lowcore.access_regs_save_area);
 872         cpu_init();
 873         rcu_cpu_starting(cpu);
 874         init_cpu_timer();
 875         vtime_init();
 876         vdso_getcpu_init();
 877         pfault_init();
 878         notify_cpu_starting(cpu);
 879         if (topology_cpu_dedicated(cpu))
 880                 set_cpu_flag(CIF_DEDICATED_CPU);
 881         else
 882                 clear_cpu_flag(CIF_DEDICATED_CPU);
 883         set_cpu_online(cpu, true);
 884         update_cpu_masks();
 885         inc_irq_stat(CPU_RST);
 886         local_irq_enable();
 887         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 888 }
 889
 890 /*
 891  *      Activate a secondary processor.
 892  */
 893 static void __no_sanitize_address smp_start_secondary(void *cpuvoid)
 894 {
 895         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 896         S390_lowcore.restart_fn = (unsigned long) do_restart;
 897         S390_lowcore.restart_data = 0;
 898         S390_lowcore.restart_source = -1UL;
 899         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 900         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 901         CALL_ON_STACK_NORETURN(smp_init_secondary, S390_lowcore.kernel_stack);
 902 }
 903
 904 /* Upping and downing of CPUs */
 905 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 906 {
 907         struct pcpu *pcpu = pcpu_devices + cpu;
 908         int rc;
 909
 910         if (pcpu->state != CPU_STATE_CONFIGURED)
 911                 return -EIO;
 912         if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
 913             SIGP_CC_ORDER_CODE_ACCEPTED)
 914                 return -EIO;
 915
 916         rc = pcpu_alloc_lowcore(pcpu, cpu);
 917         if (rc)
 918                 return rc;
 919         pcpu_prepare_secondary(pcpu, cpu);
 920         pcpu_attach_task(pcpu, tidle);
 921         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 922         /* Wait until cpu puts itself in the online & active maps */
 923         while (!cpu_online(cpu))
 924                 cpu_relax();
 925         return 0;
 926 }
 927
 928 static unsigned int setup_possible_cpus __initdata;
 929
 930 static int __init _setup_possible_cpus(char *s)
 931 {
 932         get_option(&s, &setup_possible_cpus);
 933         return 0;
 934 }
 935 early_param("possible_cpus", _setup_possible_cpus);
 936
 937 int __cpu_disable(void)
 938 {
 939         unsigned long cregs[16];
 940
 941         /* Handle possible pending IPIs */
 942         smp_handle_ext_call();
 943         set_cpu_online(smp_processor_id(), false);
 944         update_cpu_masks();
 945         /* Disable pseudo page faults on this cpu. */
 946         pfault_fini();
 947         /* Disable interrupt sources via control register. */
 948         __ctl_store(cregs, 0, 15);
 949         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 950         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 951         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 952         __ctl_load(cregs, 0, 15);
 953         clear_cpu_flag(CIF_NOHZ_DELAY);
 954         return 0;
 955 }
 956
 957 void __cpu_die(unsigned int cpu)
 958 {
 959         struct pcpu *pcpu;
 960
 961         /* Wait until target cpu is down */
 962         pcpu = pcpu_devices + cpu;
 963         while (!pcpu_stopped(pcpu))
 964                 cpu_relax();
 965         pcpu_free_lowcore(pcpu);
 966         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 967         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 968 }
 969
 970 void __noreturn cpu_die(void)
 971 {
 972         idle_task_exit();
 973         __bpon();
 974         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 975         for (;;) ;
 976 }
 977
 978 void __init smp_fill_possible_mask(void)
 979 {
 980         unsigned int possible, sclp_max, cpu;
 981
 982         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 983         sclp_max = min(smp_max_threads, sclp_max);
 984         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 985         possible = setup_possible_cpus ?: nr_cpu_ids;
 986         possible = min(possible, sclp_max);
 987         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 988                 set_cpu_possible(cpu, true);
 989 }
 990
 991 void __init smp_prepare_cpus(unsigned int max_cpus)
 992 {
 993         /* request the 0x1201 emergency signal external interrupt */
 994         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 995                 panic("Couldn't request external interrupt 0x1201");
 996         /* request the 0x1202 external call external interrupt */
 997         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 998                 panic("Couldn't request external interrupt 0x1202");
 999 }
1000
1001 void __init smp_prepare_boot_cpu(void)
1002 {
1003         struct pcpu *pcpu = pcpu_devices;
1004
1005         WARN_ON(!cpu_present(0) || !cpu_online(0));
1006         pcpu->state = CPU_STATE_CONFIGURED;
1007         S390_lowcore.percpu_offset = __per_cpu_offset[0];
1008         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
1009 }
1010
1011 void __init smp_setup_processor_id(void)
1012 {
1013         pcpu_devices[0].address = stap();
1014         S390_lowcore.cpu_nr = 0;
1015         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
1016         S390_lowcore.spinlock_index = 0;
1017 }
1018
1019 /*
1020  * the frequency of the profiling timer can be changed
1021  * by writing a multiplier value into /proc/profile.
1022  *
1023  * usually you want to run this on all CPUs ;)
1024  */
1025 int setup_profiling_timer(unsigned int multiplier)
1026 {
1027         return 0;
1028 }
1029
1030 static ssize_t cpu_configure_show(struct device *dev,
1031                                   struct device_attribute *attr, char *buf)
1032 {
1033         ssize_t count;
1034
1035         mutex_lock(&smp_cpu_state_mutex);
1036         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
1037         mutex_unlock(&smp_cpu_state_mutex);
1038         return count;
1039 }
1040
1041 static ssize_t cpu_configure_store(struct device *dev,
1042                                    struct device_attribute *attr,
1043                                    const char *buf, size_t count)
1044 {
1045         struct pcpu *pcpu;
1046         int cpu, val, rc, i;
1047         char delim;
1048
1049         if (sscanf(buf, "%d %c", &val, &delim) != 1)
1050                 return -EINVAL;
1051         if (val != 0 && val != 1)
1052                 return -EINVAL;
1053         get_online_cpus();
1054         mutex_lock(&smp_cpu_state_mutex);
1055         rc = -EBUSY;
1056         /* disallow configuration changes of online cpus and cpu 0 */
1057         cpu = dev->id;
1058         cpu = smp_get_base_cpu(cpu);
1059         if (cpu == 0)
1060                 goto out;
1061         for (i = 0; i <= smp_cpu_mtid; i++)
1062                 if (cpu_online(cpu + i))
1063                         goto out;
1064         pcpu = pcpu_devices + cpu;
1065         rc = 0;
1066         switch (val) {
1067         case 0:
1068                 if (pcpu->state != CPU_STATE_CONFIGURED)
1069                         break;
1070                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1071                 if (rc)
1072                         break;
1073                 for (i = 0; i <= smp_cpu_mtid; i++) {
1074                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1075                                 continue;
1076                         pcpu[i].state = CPU_STATE_STANDBY;
1077                         smp_cpu_set_polarization(cpu + i,
1078                                                  POLARIZATION_UNKNOWN);
1079                 }
1080                 topology_expect_change();
1081                 break;
1082         case 1:
1083                 if (pcpu->state != CPU_STATE_STANDBY)
1084                         break;
1085                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1086                 if (rc)
1087                         break;
1088                 for (i = 0; i <= smp_cpu_mtid; i++) {
1089                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1090                                 continue;
1091                         pcpu[i].state = CPU_STATE_CONFIGURED;
1092                         smp_cpu_set_polarization(cpu + i,
1093                                                  POLARIZATION_UNKNOWN);
1094                 }
1095                 topology_expect_change();
1096                 break;
1097         default:
1098                 break;
1099         }
1100 out:
1101         mutex_unlock(&smp_cpu_state_mutex);
1102         put_online_cpus();
1103         return rc ? rc : count;
1104 }
1105 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1106
1107 static ssize_t show_cpu_address(struct device *dev,
1108                                 struct device_attribute *attr, char *buf)
1109 {
1110         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1111 }
1112 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1113
1114 static struct attribute *cpu_common_attrs[] = {
1115         &dev_attr_configure.attr,
1116         &dev_attr_address.attr,
1117         NULL,
1118 };
1119
1120 static struct attribute_group cpu_common_attr_group = {
1121         .attrs = cpu_common_attrs,
1122 };
1123
1124 static struct attribute *cpu_online_attrs[] = {
1125         &dev_attr_idle_count.attr,
1126         &dev_attr_idle_time_us.attr,
1127         NULL,
1128 };
1129
1130 static struct attribute_group cpu_online_attr_group = {
1131         .attrs = cpu_online_attrs,
1132 };
1133
1134 static int smp_cpu_online(unsigned int cpu)
1135 {
1136         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1137
1138         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1139 }
1140
1141 static int smp_cpu_pre_down(unsigned int cpu)
1142 {
1143         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1144
1145         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1146         return 0;
1147 }
1148
1149 static int smp_add_present_cpu(int cpu)
1150 {
1151         struct device *s;
1152         struct cpu *c;
1153         int rc;
1154
1155         c = kzalloc(sizeof(*c), GFP_KERNEL);
1156         if (!c)
1157                 return -ENOMEM;
1158         per_cpu(cpu_device, cpu) = c;
1159         s = &c->dev;
1160         c->hotpluggable = 1;
1161         rc = register_cpu(c, cpu);
1162         if (rc)
1163                 goto out;
1164         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1165         if (rc)
1166                 goto out_cpu;
1167         rc = topology_cpu_init(c);
1168         if (rc)
1169                 goto out_topology;
1170         return 0;
1171
1172 out_topology:
1173         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1174 out_cpu:
1175         unregister_cpu(c);
1176 out:
1177         return rc;
1178 }
1179
1180 int __ref smp_rescan_cpus(void)
1181 {
1182         struct sclp_core_info *info;
1183         int nr;
1184
1185         info = kzalloc(sizeof(*info), GFP_KERNEL);
1186         if (!info)
1187                 return -ENOMEM;
1188         smp_get_core_info(info, 0);
1189         nr = __smp_rescan_cpus(info, false);
1190         kfree(info);
1191         if (nr)
1192                 topology_schedule_update();
1193         return 0;
1194 }
1195
1196 static ssize_t __ref rescan_store(struct device *dev,
1197                                   struct device_attribute *attr,
1198                                   const char *buf,
1199                                   size_t count)
1200 {
1201         int rc;
1202
1203         rc = lock_device_hotplug_sysfs();
1204         if (rc)
1205                 return rc;
1206         rc = smp_rescan_cpus();
1207         unlock_device_hotplug();
1208         return rc ? rc : count;
1209 }
1210 static DEVICE_ATTR_WO(rescan);
1211
1212 static int __init s390_smp_init(void)
1213 {
1214         int cpu, rc = 0;
1215
1216         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1217         if (rc)
1218                 return rc;
1219         for_each_present_cpu(cpu) {
1220                 rc = smp_add_present_cpu(cpu);
1221                 if (rc)
1222                         goto out;
1223         }
1224
1225         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1226                                smp_cpu_online, smp_cpu_pre_down);
1227         rc = rc <= 0 ? rc : 0;
1228 out:
1229         return rc;
1230 }
1231 subsys_initcall(s390_smp_init);
1232
1233 static __always_inline void set_new_lowcore(struct lowcore *lc)
1234 {
1235         union register_pair dst, src;
1236         u32 pfx;
1237
1238         src.even = (unsigned long) &S390_lowcore;
1239         src.odd  = sizeof(S390_lowcore);
1240         dst.even = (unsigned long) lc;
1241         dst.odd  = sizeof(*lc);
1242         pfx = (unsigned long) lc;
1243
1244         asm volatile(
1245                 "       mvcl    %[dst],%[src]\n"
1246                 "       spx     %[pfx]\n"
1247                 : [dst] "+&d" (dst.pair), [src] "+&d" (src.pair)
1248                 : [pfx] "Q" (pfx)
1249                 : "memory", "cc");
1250 }
1251
1252 static int __init smp_reinit_ipl_cpu(void)
1253 {
1254         unsigned long async_stack, nodat_stack, mcck_stack;
1255         struct lowcore *lc, *lc_ipl;
1256         unsigned long flags;
1257
1258         lc_ipl = lowcore_ptr[0];
1259         lc = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
1260         nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
1261         async_stack = stack_alloc();
1262         mcck_stack = stack_alloc();
1263         if (!lc || !nodat_stack || !async_stack || !mcck_stack)
1264                 panic("Couldn't allocate memory");
1265
1266         local_irq_save(flags);
1267         local_mcck_disable();
1268         set_new_lowcore(lc);
1269         S390_lowcore.nodat_stack = nodat_stack + STACK_INIT_OFFSET;
1270         S390_lowcore.async_stack = async_stack + STACK_INIT_OFFSET;
1271         S390_lowcore.mcck_stack = mcck_stack + STACK_INIT_OFFSET;
1272         lowcore_ptr[0] = lc;
1273         local_mcck_enable();
1274         local_irq_restore(flags);
1275
1276         free_pages(lc_ipl->async_stack - STACK_INIT_OFFSET, THREAD_SIZE_ORDER);
1277         memblock_free_late(lc_ipl->mcck_stack - STACK_INIT_OFFSET, THREAD_SIZE);
1278         memblock_free_late((unsigned long) lc_ipl, sizeof(*lc_ipl));
1279
1280         return 0;
1281 }
1282 early_initcall(smp_reinit_ipl_cpu);