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/topology.h>
  57 #include "entry.h"
  58
  59 enum {
  60         ec_schedule = 0,
  61         ec_call_function_single,
  62         ec_stop_cpu,
  63 };
  64
  65 enum {
  66         CPU_STATE_STANDBY,
  67         CPU_STATE_CONFIGURED,
  68 };
  69
  70 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  71
  72 struct pcpu {
  73         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  74         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  75         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  76         signed char state;              /* physical cpu state */
  77         signed char polarization;       /* physical polarization */
  78         u16 address;                    /* physical cpu address */
  79 };
  80
  81 static u8 boot_core_type;
  82 static struct pcpu pcpu_devices[NR_CPUS];
  83
  84 unsigned int smp_cpu_mt_shift;
  85 EXPORT_SYMBOL(smp_cpu_mt_shift);
  86
  87 unsigned int smp_cpu_mtid;
  88 EXPORT_SYMBOL(smp_cpu_mtid);
  89
  90 #ifdef CONFIG_CRASH_DUMP
  91 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  92 #endif
  93
  94 static unsigned int smp_max_threads __initdata = -1U;
  95
  96 static int __init early_nosmt(char *s)
  97 {
  98         smp_max_threads = 1;
  99         return 0;
 100 }
 101 early_param("nosmt", early_nosmt);
 102
 103 static int __init early_smt(char *s)
 104 {
 105         get_option(&s, &smp_max_threads);
 106         return 0;
 107 }
 108 early_param("smt", early_smt);
 109
 110 /*
 111  * The smp_cpu_state_mutex must be held when changing the state or polarization
 112  * member of a pcpu data structure within the pcpu_devices arreay.
 113  */
 114 DEFINE_MUTEX(smp_cpu_state_mutex);
 115
 116 /*
 117  * Signal processor helper functions.
 118  */
 119 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 120 {
 121         int cc;
 122
 123         while (1) {
 124                 cc = __pcpu_sigp(addr, order, parm, NULL);
 125                 if (cc != SIGP_CC_BUSY)
 126                         return cc;
 127                 cpu_relax();
 128         }
 129 }
 130
 131 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 132 {
 133         int cc, retry;
 134
 135         for (retry = 0; ; retry++) {
 136                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 137                 if (cc != SIGP_CC_BUSY)
 138                         break;
 139                 if (retry >= 3)
 140                         udelay(10);
 141         }
 142         return cc;
 143 }
 144
 145 static inline int pcpu_stopped(struct pcpu *pcpu)
 146 {
 147         u32 uninitialized_var(status);
 148
 149         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 150                         0, &status) != SIGP_CC_STATUS_STORED)
 151                 return 0;
 152         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 153 }
 154
 155 static inline int pcpu_running(struct pcpu *pcpu)
 156 {
 157         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 158                         0, NULL) != SIGP_CC_STATUS_STORED)
 159                 return 1;
 160         /* Status stored condition code is equivalent to cpu not running. */
 161         return 0;
 162 }
 163
 164 /*
 165  * Find struct pcpu by cpu address.
 166  */
 167 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 168 {
 169         int cpu;
 170
 171         for_each_cpu(cpu, mask)
 172                 if (pcpu_devices[cpu].address == address)
 173                         return pcpu_devices + cpu;
 174         return NULL;
 175 }
 176
 177 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 178 {
 179         int order;
 180
 181         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 182                 return;
 183         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 184         pcpu->ec_clk = get_tod_clock_fast();
 185         pcpu_sigp_retry(pcpu, order, 0);
 186 }
 187
 188 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 189 {
 190         unsigned long async_stack, nodat_stack;
 191         struct lowcore *lc;
 192
 193         if (pcpu != &pcpu_devices[0]) {
 194                 pcpu->lowcore = (struct lowcore *)
 195                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 196                 nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
 197                 if (!pcpu->lowcore || !nodat_stack)
 198                         goto out;
 199         } else {
 200                 nodat_stack = pcpu->lowcore->nodat_stack - STACK_INIT_OFFSET;
 201         }
 202         async_stack = stack_alloc();
 203         if (!async_stack)
 204                 goto out;
 205         lc = pcpu->lowcore;
 206         memcpy(lc, &S390_lowcore, 512);
 207         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 208         lc->async_stack = async_stack + STACK_INIT_OFFSET;
 209         lc->nodat_stack = nodat_stack + STACK_INIT_OFFSET;
 210         lc->cpu_nr = cpu;
 211         lc->spinlock_lockval = arch_spin_lockval(cpu);
 212         lc->spinlock_index = 0;
 213         lc->br_r1_trampoline = 0x07f1;  /* br %r1 */
 214         if (nmi_alloc_per_cpu(lc))
 215                 goto out_async;
 216         if (vdso_alloc_per_cpu(lc))
 217                 goto out_mcesa;
 218         lowcore_ptr[cpu] = lc;
 219         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 220         return 0;
 221
 222 out_mcesa:
 223         nmi_free_per_cpu(lc);
 224 out_async:
 225         stack_free(async_stack);
 226 out:
 227         if (pcpu != &pcpu_devices[0]) {
 228                 free_pages(nodat_stack, THREAD_SIZE_ORDER);
 229                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 230         }
 231         return -ENOMEM;
 232 }
 233
 234 #ifdef CONFIG_HOTPLUG_CPU
 235
 236 static void pcpu_free_lowcore(struct pcpu *pcpu)
 237 {
 238         unsigned long async_stack, nodat_stack, lowcore;
 239
 240         nodat_stack = pcpu->lowcore->nodat_stack - STACK_INIT_OFFSET;
 241         async_stack = pcpu->lowcore->async_stack - STACK_INIT_OFFSET;
 242         lowcore = (unsigned long) pcpu->lowcore;
 243
 244         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 245         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 246         vdso_free_per_cpu(pcpu->lowcore);
 247         nmi_free_per_cpu(pcpu->lowcore);
 248         stack_free(async_stack);
 249         if (pcpu == &pcpu_devices[0])
 250                 return;
 251         free_pages(nodat_stack, THREAD_SIZE_ORDER);
 252         free_pages(lowcore, LC_ORDER);
 253 }
 254
 255 #endif /* CONFIG_HOTPLUG_CPU */
 256
 257 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 258 {
 259         struct lowcore *lc = pcpu->lowcore;
 260
 261         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 262         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 263         lc->cpu_nr = cpu;
 264         lc->spinlock_lockval = arch_spin_lockval(cpu);
 265         lc->spinlock_index = 0;
 266         lc->percpu_offset = __per_cpu_offset[cpu];
 267         lc->kernel_asce = S390_lowcore.kernel_asce;
 268         lc->machine_flags = S390_lowcore.machine_flags;
 269         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 270         __ctl_store(lc->cregs_save_area, 0, 15);
 271         save_access_regs((unsigned int *) lc->access_regs_save_area);
 272         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 273                sizeof(lc->stfle_fac_list));
 274         memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list,
 275                sizeof(lc->alt_stfle_fac_list));
 276         arch_spin_lock_setup(cpu);
 277 }
 278
 279 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 280 {
 281         struct lowcore *lc = pcpu->lowcore;
 282
 283         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 284                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 285         lc->current_task = (unsigned long) tsk;
 286         lc->lpp = LPP_MAGIC;
 287         lc->current_pid = tsk->pid;
 288         lc->user_timer = tsk->thread.user_timer;
 289         lc->guest_timer = tsk->thread.guest_timer;
 290         lc->system_timer = tsk->thread.system_timer;
 291         lc->hardirq_timer = tsk->thread.hardirq_timer;
 292         lc->softirq_timer = tsk->thread.softirq_timer;
 293         lc->steal_timer = 0;
 294 }
 295
 296 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 297 {
 298         struct lowcore *lc = pcpu->lowcore;
 299
 300         lc->restart_stack = lc->nodat_stack;
 301         lc->restart_fn = (unsigned long) func;
 302         lc->restart_data = (unsigned long) data;
 303         lc->restart_source = -1UL;
 304         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 305 }
 306
 307 /*
 308  * Call function via PSW restart on pcpu and stop the current cpu.
 309  */
 310 static void __pcpu_delegate(void (*func)(void*), void *data)
 311 {
 312         func(data);     /* should not return */
 313 }
 314
 315 static void __no_sanitize_address pcpu_delegate(struct pcpu *pcpu,
 316                                                 void (*func)(void *),
 317                                                 void *data, unsigned long stack)
 318 {
 319         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 320         unsigned long source_cpu = stap();
 321
 322         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 323         if (pcpu->address == source_cpu)
 324                 CALL_ON_STACK(__pcpu_delegate, stack, 2, func, data);
 325         /* Stop target cpu (if func returns this stops the current cpu). */
 326         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 327         /* Restart func on the target cpu and stop the current cpu. */
 328         mem_assign_absolute(lc->restart_stack, stack);
 329         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 330         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 331         mem_assign_absolute(lc->restart_source, source_cpu);
 332         __bpon();
 333         asm volatile(
 334                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 335                 "       brc     2,0b    # busy, try again\n"
 336                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 337                 "       brc     2,1b    # busy, try again\n"
 338                 : : "d" (pcpu->address), "d" (source_cpu),
 339                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 340                 : "0", "1", "cc");
 341         for (;;) ;
 342 }
 343
 344 /*
 345  * Enable additional logical cpus for multi-threading.
 346  */
 347 static int pcpu_set_smt(unsigned int mtid)
 348 {
 349         int cc;
 350
 351         if (smp_cpu_mtid == mtid)
 352                 return 0;
 353         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 354         if (cc == 0) {
 355                 smp_cpu_mtid = mtid;
 356                 smp_cpu_mt_shift = 0;
 357                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 358                         smp_cpu_mt_shift++;
 359                 pcpu_devices[0].address = stap();
 360         }
 361         return cc;
 362 }
 363
 364 /*
 365  * Call function on an online CPU.
 366  */
 367 void smp_call_online_cpu(void (*func)(void *), void *data)
 368 {
 369         struct pcpu *pcpu;
 370
 371         /* Use the current cpu if it is online. */
 372         pcpu = pcpu_find_address(cpu_online_mask, stap());
 373         if (!pcpu)
 374                 /* Use the first online cpu. */
 375                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 376         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 377 }
 378
 379 /*
 380  * Call function on the ipl CPU.
 381  */
 382 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 383 {
 384         pcpu_delegate(&pcpu_devices[0], func, data,
 385                       pcpu_devices->lowcore->nodat_stack);
 386 }
 387
 388 int smp_find_processor_id(u16 address)
 389 {
 390         int cpu;
 391
 392         for_each_present_cpu(cpu)
 393                 if (pcpu_devices[cpu].address == address)
 394                         return cpu;
 395         return -1;
 396 }
 397
 398 bool arch_vcpu_is_preempted(int cpu)
 399 {
 400         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 401                 return false;
 402         if (pcpu_running(pcpu_devices + cpu))
 403                 return false;
 404         return true;
 405 }
 406 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 407
 408 void smp_yield_cpu(int cpu)
 409 {
 410         if (MACHINE_HAS_DIAG9C) {
 411                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 412                 asm volatile("diag %0,0,0x9c"
 413                              : : "d" (pcpu_devices[cpu].address));
 414         } else if (MACHINE_HAS_DIAG44) {
 415                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 416                 asm volatile("diag 0,0,0x44");
 417         }
 418 }
 419
 420 /*
 421  * Send cpus emergency shutdown signal. This gives the cpus the
 422  * opportunity to complete outstanding interrupts.
 423  */
 424 void notrace smp_emergency_stop(void)
 425 {
 426         cpumask_t cpumask;
 427         u64 end;
 428         int cpu;
 429
 430         cpumask_copy(&cpumask, cpu_online_mask);
 431         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 432
 433         end = get_tod_clock() + (1000000UL << 12);
 434         for_each_cpu(cpu, &cpumask) {
 435                 struct pcpu *pcpu = pcpu_devices + cpu;
 436                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 437                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 438                                    0, NULL) == SIGP_CC_BUSY &&
 439                        get_tod_clock() < end)
 440                         cpu_relax();
 441         }
 442         while (get_tod_clock() < end) {
 443                 for_each_cpu(cpu, &cpumask)
 444                         if (pcpu_stopped(pcpu_devices + cpu))
 445                                 cpumask_clear_cpu(cpu, &cpumask);
 446                 if (cpumask_empty(&cpumask))
 447                         break;
 448                 cpu_relax();
 449         }
 450 }
 451 NOKPROBE_SYMBOL(smp_emergency_stop);
 452
 453 /*
 454  * Stop all cpus but the current one.
 455  */
 456 void smp_send_stop(void)
 457 {
 458         int cpu;
 459
 460         /* Disable all interrupts/machine checks */
 461         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 462         trace_hardirqs_off();
 463
 464         debug_set_critical();
 465
 466         if (oops_in_progress)
 467                 smp_emergency_stop();
 468
 469         /* stop all processors */
 470         for_each_online_cpu(cpu) {
 471                 if (cpu == smp_processor_id())
 472                         continue;
 473                 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
 474                 while (!pcpu_stopped(pcpu_devices + cpu))
 475                         cpu_relax();
 476         }
 477 }
 478
 479 /*
 480  * This is the main routine where commands issued by other
 481  * cpus are handled.
 482  */
 483 static void smp_handle_ext_call(void)
 484 {
 485         unsigned long bits;
 486
 487         /* handle bit signal external calls */
 488         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 489         if (test_bit(ec_stop_cpu, &bits))
 490                 smp_stop_cpu();
 491         if (test_bit(ec_schedule, &bits))
 492                 scheduler_ipi();
 493         if (test_bit(ec_call_function_single, &bits))
 494                 generic_smp_call_function_single_interrupt();
 495 }
 496
 497 static void do_ext_call_interrupt(struct ext_code ext_code,
 498                                   unsigned int param32, unsigned long param64)
 499 {
 500         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 501         smp_handle_ext_call();
 502 }
 503
 504 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 505 {
 506         int cpu;
 507
 508         for_each_cpu(cpu, mask)
 509                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 510 }
 511
 512 void arch_send_call_function_single_ipi(int cpu)
 513 {
 514         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 515 }
 516
 517 /*
 518  * this function sends a 'reschedule' IPI to another CPU.
 519  * it goes straight through and wastes no time serializing
 520  * anything. Worst case is that we lose a reschedule ...
 521  */
 522 void smp_send_reschedule(int cpu)
 523 {
 524         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 525 }
 526
 527 /*
 528  * parameter area for the set/clear control bit callbacks
 529  */
 530 struct ec_creg_mask_parms {
 531         unsigned long orval;
 532         unsigned long andval;
 533         int cr;
 534 };
 535
 536 /*
 537  * callback for setting/clearing control bits
 538  */
 539 static void smp_ctl_bit_callback(void *info)
 540 {
 541         struct ec_creg_mask_parms *pp = info;
 542         unsigned long cregs[16];
 543
 544         __ctl_store(cregs, 0, 15);
 545         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 546         __ctl_load(cregs, 0, 15);
 547 }
 548
 549 /*
 550  * Set a bit in a control register of all cpus
 551  */
 552 void smp_ctl_set_bit(int cr, int bit)
 553 {
 554         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 555
 556         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 557 }
 558 EXPORT_SYMBOL(smp_ctl_set_bit);
 559
 560 /*
 561  * Clear a bit in a control register of all cpus
 562  */
 563 void smp_ctl_clear_bit(int cr, int bit)
 564 {
 565         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 566
 567         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 568 }
 569 EXPORT_SYMBOL(smp_ctl_clear_bit);
 570
 571 #ifdef CONFIG_CRASH_DUMP
 572
 573 int smp_store_status(int cpu)
 574 {
 575         struct pcpu *pcpu = pcpu_devices + cpu;
 576         unsigned long pa;
 577
 578         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 579         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 580                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 581                 return -EIO;
 582         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
 583                 return 0;
 584         pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
 585         if (MACHINE_HAS_GS)
 586                 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
 587         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 588                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 589                 return -EIO;
 590         return 0;
 591 }
 592
 593 /*
 594  * Collect CPU state of the previous, crashed system.
 595  * There are four cases:
 596  * 1) standard zfcp dump
 597  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 598  *    The state for all CPUs except the boot CPU needs to be collected
 599  *    with sigp stop-and-store-status. The boot CPU state is located in
 600  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 601  *    will copy the boot CPU state from the HSA.
 602  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 603  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 604  *    The state for all CPUs except the boot CPU needs to be collected
 605  *    with sigp stop-and-store-status. The firmware or the boot-loader
 606  *    stored the registers of the boot CPU in the absolute lowcore in the
 607  *    memory of the old system.
 608  * 3) kdump and the old kernel did not store the CPU state,
 609  *    or stand-alone kdump for DASD
 610  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 611  *    The state for all CPUs except the boot CPU needs to be collected
 612  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 613  *    stored the registers of the boot CPU in the memory of the old system.
 614  * 4) kdump and the old kernel stored the CPU state
 615  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 616  *    This case does not exist for s390 anymore, setup_arch explicitly
 617  *    deactivates the elfcorehdr= kernel parameter
 618  */
 619 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 620                                      bool is_boot_cpu, unsigned long page)
 621 {
 622         __vector128 *vxrs = (__vector128 *) page;
 623
 624         if (is_boot_cpu)
 625                 vxrs = boot_cpu_vector_save_area;
 626         else
 627                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 628         save_area_add_vxrs(sa, vxrs);
 629 }
 630
 631 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 632                                      bool is_boot_cpu, unsigned long page)
 633 {
 634         void *regs = (void *) page;
 635
 636         if (is_boot_cpu)
 637                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 638         else
 639                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 640         save_area_add_regs(sa, regs);
 641 }
 642
 643 void __init smp_save_dump_cpus(void)
 644 {
 645         int addr, boot_cpu_addr, max_cpu_addr;
 646         struct save_area *sa;
 647         unsigned long page;
 648         bool is_boot_cpu;
 649
 650         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 651                 /* No previous system present, normal boot. */
 652                 return;
 653         /* Allocate a page as dumping area for the store status sigps */
 654         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 655         /* Set multi-threading state to the previous system. */
 656         pcpu_set_smt(sclp.mtid_prev);
 657         boot_cpu_addr = stap();
 658         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 659         for (addr = 0; addr <= max_cpu_addr; addr++) {
 660                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 661                     SIGP_CC_NOT_OPERATIONAL)
 662                         continue;
 663                 is_boot_cpu = (addr == boot_cpu_addr);
 664                 /* Allocate save area */
 665                 sa = save_area_alloc(is_boot_cpu);
 666                 if (!sa)
 667                         panic("could not allocate memory for save area\n");
 668                 if (MACHINE_HAS_VX)
 669                         /* Get the vector registers */
 670                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 671                 /*
 672                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 673                  * of the boot CPU are stored in the HSA. To retrieve
 674                  * these registers an SCLP request is required which is
 675                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 676                  */
 677                 if (!is_boot_cpu || OLDMEM_BASE)
 678                         /* Get the CPU registers */
 679                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 680         }
 681         memblock_free(page, PAGE_SIZE);
 682         diag308_reset();
 683         pcpu_set_smt(0);
 684 }
 685 #endif /* CONFIG_CRASH_DUMP */
 686
 687 void smp_cpu_set_polarization(int cpu, int val)
 688 {
 689         pcpu_devices[cpu].polarization = val;
 690 }
 691
 692 int smp_cpu_get_polarization(int cpu)
 693 {
 694         return pcpu_devices[cpu].polarization;
 695 }
 696
 697 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 698 {
 699         static int use_sigp_detection;
 700         int address;
 701
 702         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 703                 use_sigp_detection = 1;
 704                 for (address = 0;
 705                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 706                      address += (1U << smp_cpu_mt_shift)) {
 707                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 708                             SIGP_CC_NOT_OPERATIONAL)
 709                                 continue;
 710                         info->core[info->configured].core_id =
 711                                 address >> smp_cpu_mt_shift;
 712                         info->configured++;
 713                 }
 714                 info->combined = info->configured;
 715         }
 716 }
 717
 718 static int smp_add_present_cpu(int cpu);
 719
 720 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 721 {
 722         struct pcpu *pcpu;
 723         cpumask_t avail;
 724         int cpu, nr, i, j;
 725         u16 address;
 726
 727         nr = 0;
 728         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 729         cpu = cpumask_first(&avail);
 730         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 731                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 732                         continue;
 733                 address = info->core[i].core_id << smp_cpu_mt_shift;
 734                 for (j = 0; j <= smp_cpu_mtid; j++) {
 735                         if (pcpu_find_address(cpu_present_mask, address + j))
 736                                 continue;
 737                         pcpu = pcpu_devices + cpu;
 738                         pcpu->address = address + j;
 739                         pcpu->state =
 740                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 741                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 742                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 743                         set_cpu_present(cpu, true);
 744                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 745                                 set_cpu_present(cpu, false);
 746                         else
 747                                 nr++;
 748                         cpu = cpumask_next(cpu, &avail);
 749                         if (cpu >= nr_cpu_ids)
 750                                 break;
 751                 }
 752         }
 753         return nr;
 754 }
 755
 756 void __init smp_detect_cpus(void)
 757 {
 758         unsigned int cpu, mtid, c_cpus, s_cpus;
 759         struct sclp_core_info *info;
 760         u16 address;
 761
 762         /* Get CPU information */
 763         info = memblock_alloc(sizeof(*info), 8);
 764         smp_get_core_info(info, 1);
 765         /* Find boot CPU type */
 766         if (sclp.has_core_type) {
 767                 address = stap();
 768                 for (cpu = 0; cpu < info->combined; cpu++)
 769                         if (info->core[cpu].core_id == address) {
 770                                 /* The boot cpu dictates the cpu type. */
 771                                 boot_core_type = info->core[cpu].type;
 772                                 break;
 773                         }
 774                 if (cpu >= info->combined)
 775                         panic("Could not find boot CPU type");
 776         }
 777
 778         /* Set multi-threading state for the current system */
 779         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 780         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 781         pcpu_set_smt(mtid);
 782
 783         /* Print number of CPUs */
 784         c_cpus = s_cpus = 0;
 785         for (cpu = 0; cpu < info->combined; cpu++) {
 786                 if (sclp.has_core_type &&
 787                     info->core[cpu].type != boot_core_type)
 788                         continue;
 789                 if (cpu < info->configured)
 790                         c_cpus += smp_cpu_mtid + 1;
 791                 else
 792                         s_cpus += smp_cpu_mtid + 1;
 793         }
 794         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 795
 796         /* Add CPUs present at boot */
 797         get_online_cpus();
 798         __smp_rescan_cpus(info, 0);
 799         put_online_cpus();
 800         memblock_free_early((unsigned long)info, sizeof(*info));
 801 }
 802
 803 static void smp_init_secondary(void)
 804 {
 805         int cpu = smp_processor_id();
 806
 807         S390_lowcore.last_update_clock = get_tod_clock();
 808         restore_access_regs(S390_lowcore.access_regs_save_area);
 809         cpu_init();
 810         preempt_disable();
 811         init_cpu_timer();
 812         vtime_init();
 813         pfault_init();
 814         notify_cpu_starting(smp_processor_id());
 815         if (topology_cpu_dedicated(cpu))
 816                 set_cpu_flag(CIF_DEDICATED_CPU);
 817         else
 818                 clear_cpu_flag(CIF_DEDICATED_CPU);
 819         set_cpu_online(smp_processor_id(), true);
 820         inc_irq_stat(CPU_RST);
 821         local_irq_enable();
 822         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 823 }
 824
 825 /*
 826  *      Activate a secondary processor.
 827  */
 828 static void __no_sanitize_address smp_start_secondary(void *cpuvoid)
 829 {
 830         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 831         S390_lowcore.restart_fn = (unsigned long) do_restart;
 832         S390_lowcore.restart_data = 0;
 833         S390_lowcore.restart_source = -1UL;
 834         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 835         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 836         CALL_ON_STACK(smp_init_secondary, S390_lowcore.kernel_stack, 0);
 837 }
 838
 839 /* Upping and downing of CPUs */
 840 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 841 {
 842         struct pcpu *pcpu;
 843         int base, i, rc;
 844
 845         pcpu = pcpu_devices + cpu;
 846         if (pcpu->state != CPU_STATE_CONFIGURED)
 847                 return -EIO;
 848         base = smp_get_base_cpu(cpu);
 849         for (i = 0; i <= smp_cpu_mtid; i++) {
 850                 if (base + i < nr_cpu_ids)
 851                         if (cpu_online(base + i))
 852                                 break;
 853         }
 854         /*
 855          * If this is the first CPU of the core to get online
 856          * do an initial CPU reset.
 857          */
 858         if (i > smp_cpu_mtid &&
 859             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 860             SIGP_CC_ORDER_CODE_ACCEPTED)
 861                 return -EIO;
 862
 863         rc = pcpu_alloc_lowcore(pcpu, cpu);
 864         if (rc)
 865                 return rc;
 866         pcpu_prepare_secondary(pcpu, cpu);
 867         pcpu_attach_task(pcpu, tidle);
 868         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 869         /* Wait until cpu puts itself in the online & active maps */
 870         while (!cpu_online(cpu))
 871                 cpu_relax();
 872         return 0;
 873 }
 874
 875 static unsigned int setup_possible_cpus __initdata;
 876
 877 static int __init _setup_possible_cpus(char *s)
 878 {
 879         get_option(&s, &setup_possible_cpus);
 880         return 0;
 881 }
 882 early_param("possible_cpus", _setup_possible_cpus);
 883
 884 #ifdef CONFIG_HOTPLUG_CPU
 885
 886 int __cpu_disable(void)
 887 {
 888         unsigned long cregs[16];
 889
 890         /* Handle possible pending IPIs */
 891         smp_handle_ext_call();
 892         set_cpu_online(smp_processor_id(), false);
 893         /* Disable pseudo page faults on this cpu. */
 894         pfault_fini();
 895         /* Disable interrupt sources via control register. */
 896         __ctl_store(cregs, 0, 15);
 897         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 898         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 899         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 900         __ctl_load(cregs, 0, 15);
 901         clear_cpu_flag(CIF_NOHZ_DELAY);
 902         return 0;
 903 }
 904
 905 void __cpu_die(unsigned int cpu)
 906 {
 907         struct pcpu *pcpu;
 908
 909         /* Wait until target cpu is down */
 910         pcpu = pcpu_devices + cpu;
 911         while (!pcpu_stopped(pcpu))
 912                 cpu_relax();
 913         pcpu_free_lowcore(pcpu);
 914         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 915         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 916 }
 917
 918 void __noreturn cpu_die(void)
 919 {
 920         idle_task_exit();
 921         __bpon();
 922         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 923         for (;;) ;
 924 }
 925
 926 #endif /* CONFIG_HOTPLUG_CPU */
 927
 928 void __init smp_fill_possible_mask(void)
 929 {
 930         unsigned int possible, sclp_max, cpu;
 931
 932         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 933         sclp_max = min(smp_max_threads, sclp_max);
 934         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 935         possible = setup_possible_cpus ?: nr_cpu_ids;
 936         possible = min(possible, sclp_max);
 937         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 938                 set_cpu_possible(cpu, true);
 939 }
 940
 941 void __init smp_prepare_cpus(unsigned int max_cpus)
 942 {
 943         /* request the 0x1201 emergency signal external interrupt */
 944         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 945                 panic("Couldn't request external interrupt 0x1201");
 946         /* request the 0x1202 external call external interrupt */
 947         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 948                 panic("Couldn't request external interrupt 0x1202");
 949 }
 950
 951 void __init smp_prepare_boot_cpu(void)
 952 {
 953         struct pcpu *pcpu = pcpu_devices;
 954
 955         WARN_ON(!cpu_present(0) || !cpu_online(0));
 956         pcpu->state = CPU_STATE_CONFIGURED;
 957         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 958         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 959         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 960 }
 961
 962 void __init smp_cpus_done(unsigned int max_cpus)
 963 {
 964 }
 965
 966 void __init smp_setup_processor_id(void)
 967 {
 968         pcpu_devices[0].address = stap();
 969         S390_lowcore.cpu_nr = 0;
 970         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 971         S390_lowcore.spinlock_index = 0;
 972 }
 973
 974 /*
 975  * the frequency of the profiling timer can be changed
 976  * by writing a multiplier value into /proc/profile.
 977  *
 978  * usually you want to run this on all CPUs ;)
 979  */
 980 int setup_profiling_timer(unsigned int multiplier)
 981 {
 982         return 0;
 983 }
 984
 985 #ifdef CONFIG_HOTPLUG_CPU
 986 static ssize_t cpu_configure_show(struct device *dev,
 987                                   struct device_attribute *attr, char *buf)
 988 {
 989         ssize_t count;
 990
 991         mutex_lock(&smp_cpu_state_mutex);
 992         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 993         mutex_unlock(&smp_cpu_state_mutex);
 994         return count;
 995 }
 996
 997 static ssize_t cpu_configure_store(struct device *dev,
 998                                    struct device_attribute *attr,
 999                                    const char *buf, size_t count)
1000 {
1001         struct pcpu *pcpu;
1002         int cpu, val, rc, i;
1003         char delim;
1004
1005         if (sscanf(buf, "%d %c", &val, &delim) != 1)
1006                 return -EINVAL;
1007         if (val != 0 && val != 1)
1008                 return -EINVAL;
1009         get_online_cpus();
1010         mutex_lock(&smp_cpu_state_mutex);
1011         rc = -EBUSY;
1012         /* disallow configuration changes of online cpus and cpu 0 */
1013         cpu = dev->id;
1014         cpu = smp_get_base_cpu(cpu);
1015         if (cpu == 0)
1016                 goto out;
1017         for (i = 0; i <= smp_cpu_mtid; i++)
1018                 if (cpu_online(cpu + i))
1019                         goto out;
1020         pcpu = pcpu_devices + cpu;
1021         rc = 0;
1022         switch (val) {
1023         case 0:
1024                 if (pcpu->state != CPU_STATE_CONFIGURED)
1025                         break;
1026                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1027                 if (rc)
1028                         break;
1029                 for (i = 0; i <= smp_cpu_mtid; i++) {
1030                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1031                                 continue;
1032                         pcpu[i].state = CPU_STATE_STANDBY;
1033                         smp_cpu_set_polarization(cpu + i,
1034                                                  POLARIZATION_UNKNOWN);
1035                 }
1036                 topology_expect_change();
1037                 break;
1038         case 1:
1039                 if (pcpu->state != CPU_STATE_STANDBY)
1040                         break;
1041                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1042                 if (rc)
1043                         break;
1044                 for (i = 0; i <= smp_cpu_mtid; i++) {
1045                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1046                                 continue;
1047                         pcpu[i].state = CPU_STATE_CONFIGURED;
1048                         smp_cpu_set_polarization(cpu + i,
1049                                                  POLARIZATION_UNKNOWN);
1050                 }
1051                 topology_expect_change();
1052                 break;
1053         default:
1054                 break;
1055         }
1056 out:
1057         mutex_unlock(&smp_cpu_state_mutex);
1058         put_online_cpus();
1059         return rc ? rc : count;
1060 }
1061 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1062 #endif /* CONFIG_HOTPLUG_CPU */
1063
1064 static ssize_t show_cpu_address(struct device *dev,
1065                                 struct device_attribute *attr, char *buf)
1066 {
1067         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1068 }
1069 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1070
1071 static struct attribute *cpu_common_attrs[] = {
1072 #ifdef CONFIG_HOTPLUG_CPU
1073         &dev_attr_configure.attr,
1074 #endif
1075         &dev_attr_address.attr,
1076         NULL,
1077 };
1078
1079 static struct attribute_group cpu_common_attr_group = {
1080         .attrs = cpu_common_attrs,
1081 };
1082
1083 static struct attribute *cpu_online_attrs[] = {
1084         &dev_attr_idle_count.attr,
1085         &dev_attr_idle_time_us.attr,
1086         NULL,
1087 };
1088
1089 static struct attribute_group cpu_online_attr_group = {
1090         .attrs = cpu_online_attrs,
1091 };
1092
1093 static int smp_cpu_online(unsigned int cpu)
1094 {
1095         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1096
1097         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1098 }
1099 static int smp_cpu_pre_down(unsigned int cpu)
1100 {
1101         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1102
1103         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1104         return 0;
1105 }
1106
1107 static int smp_add_present_cpu(int cpu)
1108 {
1109         struct device *s;
1110         struct cpu *c;
1111         int rc;
1112
1113         c = kzalloc(sizeof(*c), GFP_KERNEL);
1114         if (!c)
1115                 return -ENOMEM;
1116         per_cpu(cpu_device, cpu) = c;
1117         s = &c->dev;
1118         c->hotpluggable = 1;
1119         rc = register_cpu(c, cpu);
1120         if (rc)
1121                 goto out;
1122         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1123         if (rc)
1124                 goto out_cpu;
1125         rc = topology_cpu_init(c);
1126         if (rc)
1127                 goto out_topology;
1128         return 0;
1129
1130 out_topology:
1131         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1132 out_cpu:
1133 #ifdef CONFIG_HOTPLUG_CPU
1134         unregister_cpu(c);
1135 #endif
1136 out:
1137         return rc;
1138 }
1139
1140 #ifdef CONFIG_HOTPLUG_CPU
1141
1142 int __ref smp_rescan_cpus(void)
1143 {
1144         struct sclp_core_info *info;
1145         int nr;
1146
1147         info = kzalloc(sizeof(*info), GFP_KERNEL);
1148         if (!info)
1149                 return -ENOMEM;
1150         smp_get_core_info(info, 0);
1151         get_online_cpus();
1152         mutex_lock(&smp_cpu_state_mutex);
1153         nr = __smp_rescan_cpus(info, 1);
1154         mutex_unlock(&smp_cpu_state_mutex);
1155         put_online_cpus();
1156         kfree(info);
1157         if (nr)
1158                 topology_schedule_update();
1159         return 0;
1160 }
1161
1162 static ssize_t __ref rescan_store(struct device *dev,
1163                                   struct device_attribute *attr,
1164                                   const char *buf,
1165                                   size_t count)
1166 {
1167         int rc;
1168
1169         rc = smp_rescan_cpus();
1170         return rc ? rc : count;
1171 }
1172 static DEVICE_ATTR_WO(rescan);
1173 #endif /* CONFIG_HOTPLUG_CPU */
1174
1175 static int __init s390_smp_init(void)
1176 {
1177         int cpu, rc = 0;
1178
1179 #ifdef CONFIG_HOTPLUG_CPU
1180         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1181         if (rc)
1182                 return rc;
1183 #endif
1184         for_each_present_cpu(cpu) {
1185                 rc = smp_add_present_cpu(cpu);
1186                 if (rc)
1187                         goto out;
1188         }
1189
1190         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1191                                smp_cpu_online, smp_cpu_pre_down);
1192         rc = rc <= 0 ? rc : 0;
1193 out:
1194         return rc;
1195 }
1196 subsys_initcall(s390_smp_init);