kernel/arch/s390/kernel/smp.c

   1 /*
   2  *  SMP related functions
   3  *
   4  *    Copyright IBM Corp. 1999, 2012
   5  *    Author(s): Denis Joseph Barrow,
   6  *               Martin Schwidefsky <schwidefsky@de.ibm.com>,
   7  *               Heiko Carstens <heiko.carstens@de.ibm.com>,
   8  *
   9  *  based on other smp stuff by
  10  *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
  11  *    (c) 1998 Ingo Molnar
  12  *
  13  * The code outside of smp.c uses logical cpu numbers, only smp.c does
  14  * the translation of logical to physical cpu ids. All new code that
  15  * operates on physical cpu numbers needs to go into smp.c.
  16  */
  17
  18 #define KMSG_COMPONENT "cpu"
  19 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  20
  21 #include <linux/workqueue.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/mm.h>
  25 #include <linux/err.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/kernel_stat.h>
  28 #include <linux/delay.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/irqflags.h>
  31 #include <linux/cpu.h>
  32 #include <linux/slab.h>
  33 #include <linux/crash_dump.h>
  34 #include <linux/memblock.h>
  35 #include <asm/asm-offsets.h>
  36 #include <asm/diag.h>
  37 #include <asm/switch_to.h>
  38 #include <asm/facility.h>
  39 #include <asm/ipl.h>
  40 #include <asm/setup.h>
  41 #include <asm/irq.h>
  42 #include <asm/tlbflush.h>
  43 #include <asm/vtimer.h>
  44 #include <asm/lowcore.h>
  45 #include <asm/sclp.h>
  46 #include <asm/vdso.h>
  47 #include <asm/debug.h>
  48 #include <asm/os_info.h>
  49 #include <asm/sigp.h>
  50 #include <asm/idle.h>
  51 #include "entry.h"
  52
  53 enum {
  54         ec_schedule = 0,
  55         ec_call_function_single,
  56         ec_stop_cpu,
  57 };
  58
  59 enum {
  60         CPU_STATE_STANDBY,
  61         CPU_STATE_CONFIGURED,
  62 };
  63
  64 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  65
  66 struct pcpu {
  67         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
  68         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  69         signed char state;              /* physical cpu state */
  70         signed char polarization;       /* physical polarization */
  71         u16 address;                    /* physical cpu address */
  72 };
  73
  74 static u8 boot_core_type;
  75 static struct pcpu pcpu_devices[NR_CPUS];
  76
  77 unsigned int smp_cpu_mt_shift;
  78 EXPORT_SYMBOL(smp_cpu_mt_shift);
  79
  80 unsigned int smp_cpu_mtid;
  81 EXPORT_SYMBOL(smp_cpu_mtid);
  82
  83 static unsigned int smp_max_threads __initdata = -1U;
  84
  85 static int __init early_nosmt(char *s)
  86 {
  87         smp_max_threads = 1;
  88         return 0;
  89 }
  90 early_param("nosmt", early_nosmt);
  91
  92 static int __init early_smt(char *s)
  93 {
  94         get_option(&s, &smp_max_threads);
  95         return 0;
  96 }
  97 early_param("smt", early_smt);
  98
  99 /*
 100  * The smp_cpu_state_mutex must be held when changing the state or polarization
 101  * member of a pcpu data structure within the pcpu_devices arreay.
 102  */
 103 DEFINE_MUTEX(smp_cpu_state_mutex);
 104
 105 /*
 106  * Signal processor helper functions.
 107  */
 108 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm,
 109                                     u32 *status)
 110 {
 111         int cc;
 112
 113         while (1) {
 114                 cc = __pcpu_sigp(addr, order, parm, NULL);
 115                 if (cc != SIGP_CC_BUSY)
 116                         return cc;
 117                 cpu_relax();
 118         }
 119 }
 120
 121 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 122 {
 123         int cc, retry;
 124
 125         for (retry = 0; ; retry++) {
 126                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 127                 if (cc != SIGP_CC_BUSY)
 128                         break;
 129                 if (retry >= 3)
 130                         udelay(10);
 131         }
 132         return cc;
 133 }
 134
 135 static inline int pcpu_stopped(struct pcpu *pcpu)
 136 {
 137         u32 uninitialized_var(status);
 138
 139         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 140                         0, &status) != SIGP_CC_STATUS_STORED)
 141                 return 0;
 142         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 143 }
 144
 145 static inline int pcpu_running(struct pcpu *pcpu)
 146 {
 147         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 148                         0, NULL) != SIGP_CC_STATUS_STORED)
 149                 return 1;
 150         /* Status stored condition code is equivalent to cpu not running. */
 151         return 0;
 152 }
 153
 154 /*
 155  * Find struct pcpu by cpu address.
 156  */
 157 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 158 {
 159         int cpu;
 160
 161         for_each_cpu(cpu, mask)
 162                 if (pcpu_devices[cpu].address == address)
 163                         return pcpu_devices + cpu;
 164         return NULL;
 165 }
 166
 167 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 168 {
 169         int order;
 170
 171         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 172                 return;
 173         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 174         pcpu_sigp_retry(pcpu, order, 0);
 175 }
 176
 177 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 178 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 179
 180 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 181 {
 182         unsigned long async_stack, panic_stack;
 183         struct _lowcore *lc;
 184
 185         if (pcpu != &pcpu_devices[0]) {
 186                 pcpu->lowcore = (struct _lowcore *)
 187                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 188                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 189                 panic_stack = __get_free_page(GFP_KERNEL);
 190                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 191                         goto out;
 192         } else {
 193                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 194                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 195         }
 196         lc = pcpu->lowcore;
 197         memcpy(lc, &S390_lowcore, 512);
 198         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 199         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 200         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 201         lc->cpu_nr = cpu;
 202         lc->spinlock_lockval = arch_spin_lockval(cpu);
 203         if (MACHINE_HAS_VX)
 204                 lc->vector_save_area_addr =
 205                         (unsigned long) &lc->vector_save_area;
 206         if (vdso_alloc_per_cpu(lc))
 207                 goto out;
 208         lowcore_ptr[cpu] = lc;
 209         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 210         return 0;
 211 out:
 212         if (pcpu != &pcpu_devices[0]) {
 213                 free_page(panic_stack);
 214                 free_pages(async_stack, ASYNC_ORDER);
 215                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 216         }
 217         return -ENOMEM;
 218 }
 219
 220 #ifdef CONFIG_HOTPLUG_CPU
 221
 222 static void pcpu_free_lowcore(struct pcpu *pcpu)
 223 {
 224         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 225         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 226         vdso_free_per_cpu(pcpu->lowcore);
 227         if (pcpu == &pcpu_devices[0])
 228                 return;
 229         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 230         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 231         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 232 }
 233
 234 #endif /* CONFIG_HOTPLUG_CPU */
 235
 236 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 237 {
 238         struct _lowcore *lc = pcpu->lowcore;
 239
 240         if (MACHINE_HAS_TLB_LC)
 241                 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 242         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 243         atomic_inc(&init_mm.context.attach_count);
 244         lc->cpu_nr = cpu;
 245         lc->spinlock_lockval = arch_spin_lockval(cpu);
 246         lc->percpu_offset = __per_cpu_offset[cpu];
 247         lc->kernel_asce = S390_lowcore.kernel_asce;
 248         lc->machine_flags = S390_lowcore.machine_flags;
 249         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 250         __ctl_store(lc->cregs_save_area, 0, 15);
 251         save_access_regs((unsigned int *) lc->access_regs_save_area);
 252         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 253                MAX_FACILITY_BIT/8);
 254 }
 255
 256 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 257 {
 258         struct _lowcore *lc = pcpu->lowcore;
 259         struct thread_info *ti = task_thread_info(tsk);
 260
 261         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 262                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 263         lc->thread_info = (unsigned long) task_thread_info(tsk);
 264         lc->current_task = (unsigned long) tsk;
 265         lc->lpp = LPP_MAGIC;
 266         lc->current_pid = tsk->pid;
 267         lc->user_timer = ti->user_timer;
 268         lc->system_timer = ti->system_timer;
 269         lc->steal_timer = 0;
 270 }
 271
 272 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 273 {
 274         struct _lowcore *lc = pcpu->lowcore;
 275
 276         lc->restart_stack = lc->kernel_stack;
 277         lc->restart_fn = (unsigned long) func;
 278         lc->restart_data = (unsigned long) data;
 279         lc->restart_source = -1UL;
 280         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 281 }
 282
 283 /*
 284  * Call function via PSW restart on pcpu and stop the current cpu.
 285  */
 286 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 287                           void *data, unsigned long stack)
 288 {
 289         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 290         unsigned long source_cpu = stap();
 291
 292         __load_psw_mask(PSW_KERNEL_BITS);
 293         if (pcpu->address == source_cpu)
 294                 func(data);     /* should not return */
 295         /* Stop target cpu (if func returns this stops the current cpu). */
 296         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 297         /* Restart func on the target cpu and stop the current cpu. */
 298         mem_assign_absolute(lc->restart_stack, stack);
 299         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 300         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 301         mem_assign_absolute(lc->restart_source, source_cpu);
 302         asm volatile(
 303                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 304                 "       brc     2,0b    # busy, try again\n"
 305                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 306                 "       brc     2,1b    # busy, try again\n"
 307                 : : "d" (pcpu->address), "d" (source_cpu),
 308                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 309                 : "0", "1", "cc");
 310         for (;;) ;
 311 }
 312
 313 /*
 314  * Enable additional logical cpus for multi-threading.
 315  */
 316 static int pcpu_set_smt(unsigned int mtid)
 317 {
 318         register unsigned long reg1 asm ("1") = (unsigned long) mtid;
 319         int cc;
 320
 321         if (smp_cpu_mtid == mtid)
 322                 return 0;
 323         asm volatile(
 324                 "       sigp    %1,0,%2 # sigp set multi-threading\n"
 325                 "       ipm     %0\n"
 326                 "       srl     %0,28\n"
 327                 : "=d" (cc) : "d" (reg1), "K" (SIGP_SET_MULTI_THREADING)
 328                 : "cc");
 329         if (cc == 0) {
 330                 smp_cpu_mtid = mtid;
 331                 smp_cpu_mt_shift = 0;
 332                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 333                         smp_cpu_mt_shift++;
 334                 pcpu_devices[0].address = stap();
 335         }
 336         return cc;
 337 }
 338
 339 /*
 340  * Call function on an online CPU.
 341  */
 342 void smp_call_online_cpu(void (*func)(void *), void *data)
 343 {
 344         struct pcpu *pcpu;
 345
 346         /* Use the current cpu if it is online. */
 347         pcpu = pcpu_find_address(cpu_online_mask, stap());
 348         if (!pcpu)
 349                 /* Use the first online cpu. */
 350                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 351         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 352 }
 353
 354 /*
 355  * Call function on the ipl CPU.
 356  */
 357 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 358 {
 359         pcpu_delegate(&pcpu_devices[0], func, data,
 360                       pcpu_devices->lowcore->panic_stack -
 361                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 362 }
 363
 364 int smp_find_processor_id(u16 address)
 365 {
 366         int cpu;
 367
 368         for_each_present_cpu(cpu)
 369                 if (pcpu_devices[cpu].address == address)
 370                         return cpu;
 371         return -1;
 372 }
 373
 374 int smp_vcpu_scheduled(int cpu)
 375 {
 376         return pcpu_running(pcpu_devices + cpu);
 377 }
 378
 379 void smp_yield_cpu(int cpu)
 380 {
 381         if (MACHINE_HAS_DIAG9C) {
 382                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 383                 asm volatile("diag %0,0,0x9c"
 384                              : : "d" (pcpu_devices[cpu].address));
 385         } else if (MACHINE_HAS_DIAG44) {
 386                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 387                 asm volatile("diag 0,0,0x44");
 388         }
 389 }
 390
 391 /*
 392  * Send cpus emergency shutdown signal. This gives the cpus the
 393  * opportunity to complete outstanding interrupts.
 394  */
 395 static void smp_emergency_stop(cpumask_t *cpumask)
 396 {
 397         u64 end;
 398         int cpu;
 399
 400         end = get_tod_clock() + (1000000UL << 12);
 401         for_each_cpu(cpu, cpumask) {
 402                 struct pcpu *pcpu = pcpu_devices + cpu;
 403                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 404                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 405                                    0, NULL) == SIGP_CC_BUSY &&
 406                        get_tod_clock() < end)
 407                         cpu_relax();
 408         }
 409         while (get_tod_clock() < end) {
 410                 for_each_cpu(cpu, cpumask)
 411                         if (pcpu_stopped(pcpu_devices + cpu))
 412                                 cpumask_clear_cpu(cpu, cpumask);
 413                 if (cpumask_empty(cpumask))
 414                         break;
 415                 cpu_relax();
 416         }
 417 }
 418
 419 /*
 420  * Stop all cpus but the current one.
 421  */
 422 void smp_send_stop(void)
 423 {
 424         cpumask_t cpumask;
 425         int cpu;
 426
 427         /* Disable all interrupts/machine checks */
 428         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 429         trace_hardirqs_off();
 430
 431         debug_set_critical();
 432         cpumask_copy(&cpumask, cpu_online_mask);
 433         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 434
 435         if (oops_in_progress)
 436                 smp_emergency_stop(&cpumask);
 437
 438         /* stop all processors */
 439         for_each_cpu(cpu, &cpumask) {
 440                 struct pcpu *pcpu = pcpu_devices + cpu;
 441                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 442                 while (!pcpu_stopped(pcpu))
 443                         cpu_relax();
 444         }
 445 }
 446
 447 /*
 448  * This is the main routine where commands issued by other
 449  * cpus are handled.
 450  */
 451 static void smp_handle_ext_call(void)
 452 {
 453         unsigned long bits;
 454
 455         /* handle bit signal external calls */
 456         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 457         if (test_bit(ec_stop_cpu, &bits))
 458                 smp_stop_cpu();
 459         if (test_bit(ec_schedule, &bits))
 460                 scheduler_ipi();
 461         if (test_bit(ec_call_function_single, &bits))
 462                 generic_smp_call_function_single_interrupt();
 463 }
 464
 465 static void do_ext_call_interrupt(struct ext_code ext_code,
 466                                   unsigned int param32, unsigned long param64)
 467 {
 468         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 469         smp_handle_ext_call();
 470 }
 471
 472 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 473 {
 474         int cpu;
 475
 476         for_each_cpu(cpu, mask)
 477                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 478 }
 479
 480 void arch_send_call_function_single_ipi(int cpu)
 481 {
 482         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 483 }
 484
 485 /*
 486  * this function sends a 'reschedule' IPI to another CPU.
 487  * it goes straight through and wastes no time serializing
 488  * anything. Worst case is that we lose a reschedule ...
 489  */
 490 void smp_send_reschedule(int cpu)
 491 {
 492         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 493 }
 494
 495 /*
 496  * parameter area for the set/clear control bit callbacks
 497  */
 498 struct ec_creg_mask_parms {
 499         unsigned long orval;
 500         unsigned long andval;
 501         int cr;
 502 };
 503
 504 /*
 505  * callback for setting/clearing control bits
 506  */
 507 static void smp_ctl_bit_callback(void *info)
 508 {
 509         struct ec_creg_mask_parms *pp = info;
 510         unsigned long cregs[16];
 511
 512         __ctl_store(cregs, 0, 15);
 513         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 514         __ctl_load(cregs, 0, 15);
 515 }
 516
 517 /*
 518  * Set a bit in a control register of all cpus
 519  */
 520 void smp_ctl_set_bit(int cr, int bit)
 521 {
 522         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 523
 524         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 525 }
 526 EXPORT_SYMBOL(smp_ctl_set_bit);
 527
 528 /*
 529  * Clear a bit in a control register of all cpus
 530  */
 531 void smp_ctl_clear_bit(int cr, int bit)
 532 {
 533         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 534
 535         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 536 }
 537 EXPORT_SYMBOL(smp_ctl_clear_bit);
 538
 539 #ifdef CONFIG_CRASH_DUMP
 540
 541 static void __init __smp_store_cpu_state(struct save_area_ext *sa_ext,
 542                                          u16 address, int is_boot_cpu)
 543 {
 544         void *lc = (void *)(unsigned long) store_prefix();
 545         unsigned long vx_sa;
 546
 547         if (is_boot_cpu) {
 548                 /* Copy the registers of the boot CPU. */
 549                 copy_oldmem_page(1, (void *) &sa_ext->sa, sizeof(sa_ext->sa),
 550                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 551                 if (MACHINE_HAS_VX)
 552                         save_vx_regs_safe(sa_ext->vx_regs);
 553                 return;
 554         }
 555         /* Get the registers of a non-boot cpu. */
 556         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
 557         memcpy_real(&sa_ext->sa, lc + SAVE_AREA_BASE, sizeof(sa_ext->sa));
 558         if (!MACHINE_HAS_VX)
 559                 return;
 560         /* Get the VX registers */
 561         vx_sa = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 562         if (!vx_sa)
 563                 panic("could not allocate memory for VX save area\n");
 564         __pcpu_sigp_relax(address, SIGP_STORE_ADDITIONAL_STATUS, vx_sa, NULL);
 565         memcpy(sa_ext->vx_regs, (void *) vx_sa, sizeof(sa_ext->vx_regs));
 566         memblock_free(vx_sa, PAGE_SIZE);
 567 }
 568
 569 int smp_store_status(int cpu)
 570 {
 571         unsigned long vx_sa;
 572         struct pcpu *pcpu;
 573
 574         pcpu = pcpu_devices + cpu;
 575         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
 576                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
 577                 return -EIO;
 578         if (!MACHINE_HAS_VX)
 579                 return 0;
 580         vx_sa = __pa(pcpu->lowcore->vector_save_area_addr);
 581         __pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 582                           vx_sa, NULL);
 583         return 0;
 584 }
 585
 586 #endif /* CONFIG_CRASH_DUMP */
 587
 588 /*
 589  * Collect CPU state of the previous, crashed system.
 590  * There are four cases:
 591  * 1) standard zfcp dump
 592  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 593  *    The state for all CPUs except the boot CPU needs to be collected
 594  *    with sigp stop-and-store-status. The boot CPU state is located in
 595  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 596  *    will allocate the save area and copy the boot CPU state from the HSA.
 597  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 598  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 599  *    The state for all CPUs except the boot CPU needs to be collected
 600  *    with sigp stop-and-store-status. The firmware or the boot-loader
 601  *    stored the registers of the boot CPU in the absolute lowcore in the
 602  *    memory of the old system.
 603  * 3) kdump and the old kernel did not store the CPU state,
 604  *    or stand-alone kdump for DASD
 605  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 606  *    The state for all CPUs except the boot CPU needs to be collected
 607  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 608  *    stored the registers of the boot CPU in the memory of the old system.
 609  * 4) kdump and the old kernel stored the CPU state
 610  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 611  *    The state of all CPUs is stored in ELF sections in the memory of the
 612  *    old system. The ELF sections are picked up by the crash_dump code
 613  *    via elfcorehdr_addr.
 614  */
 615 void __init smp_save_dump_cpus(void)
 616 {
 617 #ifdef CONFIG_CRASH_DUMP
 618         int addr, cpu, boot_cpu_addr, max_cpu_addr;
 619         struct save_area_ext *sa_ext;
 620         bool is_boot_cpu;
 621
 622         if (is_kdump_kernel())
 623                 /* Previous system stored the CPU states. Nothing to do. */
 624                 return;
 625         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 626                 /* No previous system present, normal boot. */
 627                 return;
 628         /* Set multi-threading state to the previous system. */
 629         pcpu_set_smt(sclp.mtid_prev);
 630         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 631         for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
 632                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
 633                     SIGP_CC_NOT_OPERATIONAL)
 634                         continue;
 635                 cpu += 1;
 636         }
 637         dump_save_areas.areas = (void *)memblock_alloc(sizeof(void *) * cpu, 8);
 638         dump_save_areas.count = cpu;
 639         boot_cpu_addr = stap();
 640         for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
 641                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
 642                     SIGP_CC_NOT_OPERATIONAL)
 643                         continue;
 644                 sa_ext = (void *) memblock_alloc(sizeof(*sa_ext), 8);
 645                 dump_save_areas.areas[cpu] = sa_ext;
 646                 if (!sa_ext)
 647                         panic("could not allocate memory for save area\n");
 648                 is_boot_cpu = (addr == boot_cpu_addr);
 649                 cpu += 1;
 650                 if (is_boot_cpu && !OLDMEM_BASE)
 651                         /* Skip boot CPU for standard zfcp dump. */
 652                         continue;
 653                 /* Get state for this CPU. */
 654                 __smp_store_cpu_state(sa_ext, addr, is_boot_cpu);
 655         }
 656         diag308_reset();
 657         pcpu_set_smt(0);
 658 #endif /* CONFIG_CRASH_DUMP */
 659 }
 660
 661 void smp_cpu_set_polarization(int cpu, int val)
 662 {
 663         pcpu_devices[cpu].polarization = val;
 664 }
 665
 666 int smp_cpu_get_polarization(int cpu)
 667 {
 668         return pcpu_devices[cpu].polarization;
 669 }
 670
 671 static struct sclp_core_info *smp_get_core_info(void)
 672 {
 673         static int use_sigp_detection;
 674         struct sclp_core_info *info;
 675         int address;
 676
 677         info = kzalloc(sizeof(*info), GFP_KERNEL);
 678         if (info && (use_sigp_detection || sclp_get_core_info(info))) {
 679                 use_sigp_detection = 1;
 680                 for (address = 0;
 681                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 682                      address += (1U << smp_cpu_mt_shift)) {
 683                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 684                             SIGP_CC_NOT_OPERATIONAL)
 685                                 continue;
 686                         info->core[info->configured].core_id =
 687                                 address >> smp_cpu_mt_shift;
 688                         info->configured++;
 689                 }
 690                 info->combined = info->configured;
 691         }
 692         return info;
 693 }
 694
 695 static int smp_add_present_cpu(int cpu);
 696
 697 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 698 {
 699         struct pcpu *pcpu;
 700         cpumask_t avail;
 701         int cpu, nr, i, j;
 702         u16 address;
 703
 704         nr = 0;
 705         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 706         cpu = cpumask_first(&avail);
 707         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 708                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 709                         continue;
 710                 address = info->core[i].core_id << smp_cpu_mt_shift;
 711                 for (j = 0; j <= smp_cpu_mtid; j++) {
 712                         if (pcpu_find_address(cpu_present_mask, address + j))
 713                                 continue;
 714                         pcpu = pcpu_devices + cpu;
 715                         pcpu->address = address + j;
 716                         pcpu->state =
 717                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 718                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 719                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 720                         set_cpu_present(cpu, true);
 721                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 722                                 set_cpu_present(cpu, false);
 723                         else
 724                                 nr++;
 725                         cpu = cpumask_next(cpu, &avail);
 726                         if (cpu >= nr_cpu_ids)
 727                                 break;
 728                 }
 729         }
 730         return nr;
 731 }
 732
 733 static void __init smp_detect_cpus(void)
 734 {
 735         unsigned int cpu, mtid, c_cpus, s_cpus;
 736         struct sclp_core_info *info;
 737         u16 address;
 738
 739         /* Get CPU information */
 740         info = smp_get_core_info();
 741         if (!info)
 742                 panic("smp_detect_cpus failed to allocate memory\n");
 743
 744         /* Find boot CPU type */
 745         if (sclp.has_core_type) {
 746                 address = stap();
 747                 for (cpu = 0; cpu < info->combined; cpu++)
 748                         if (info->core[cpu].core_id == address) {
 749                                 /* The boot cpu dictates the cpu type. */
 750                                 boot_core_type = info->core[cpu].type;
 751                                 break;
 752                         }
 753                 if (cpu >= info->combined)
 754                         panic("Could not find boot CPU type");
 755         }
 756
 757         /* Set multi-threading state for the current system */
 758         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 759         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 760         pcpu_set_smt(mtid);
 761
 762         /* Print number of CPUs */
 763         c_cpus = s_cpus = 0;
 764         for (cpu = 0; cpu < info->combined; cpu++) {
 765                 if (sclp.has_core_type &&
 766                     info->core[cpu].type != boot_core_type)
 767                         continue;
 768                 if (cpu < info->configured)
 769                         c_cpus += smp_cpu_mtid + 1;
 770                 else
 771                         s_cpus += smp_cpu_mtid + 1;
 772         }
 773         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 774
 775         /* Add CPUs present at boot */
 776         get_online_cpus();
 777         __smp_rescan_cpus(info, 0);
 778         put_online_cpus();
 779         kfree(info);
 780 }
 781
 782 /*
 783  *      Activate a secondary processor.
 784  */
 785 static void smp_start_secondary(void *cpuvoid)
 786 {
 787         S390_lowcore.last_update_clock = get_tod_clock();
 788         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 789         S390_lowcore.restart_fn = (unsigned long) do_restart;
 790         S390_lowcore.restart_data = 0;
 791         S390_lowcore.restart_source = -1UL;
 792         restore_access_regs(S390_lowcore.access_regs_save_area);
 793         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 794         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 795         cpu_init();
 796         preempt_disable();
 797         init_cpu_timer();
 798         vtime_init();
 799         pfault_init();
 800         notify_cpu_starting(smp_processor_id());
 801         set_cpu_online(smp_processor_id(), true);
 802         inc_irq_stat(CPU_RST);
 803         local_irq_enable();
 804         cpu_startup_entry(CPUHP_ONLINE);
 805 }
 806
 807 /* Upping and downing of CPUs */
 808 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 809 {
 810         struct pcpu *pcpu;
 811         int base, i, rc;
 812
 813         pcpu = pcpu_devices + cpu;
 814         if (pcpu->state != CPU_STATE_CONFIGURED)
 815                 return -EIO;
 816         base = cpu - (cpu % (smp_cpu_mtid + 1));
 817         for (i = 0; i <= smp_cpu_mtid; i++) {
 818                 if (base + i < nr_cpu_ids)
 819                         if (cpu_online(base + i))
 820                                 break;
 821         }
 822         /*
 823          * If this is the first CPU of the core to get online
 824          * do an initial CPU reset.
 825          */
 826         if (i > smp_cpu_mtid &&
 827             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 828             SIGP_CC_ORDER_CODE_ACCEPTED)
 829                 return -EIO;
 830
 831         rc = pcpu_alloc_lowcore(pcpu, cpu);
 832         if (rc)
 833                 return rc;
 834         pcpu_prepare_secondary(pcpu, cpu);
 835         pcpu_attach_task(pcpu, tidle);
 836         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 837         /* Wait until cpu puts itself in the online & active maps */
 838         while (!cpu_online(cpu) || !cpu_active(cpu))
 839                 cpu_relax();
 840         return 0;
 841 }
 842
 843 static unsigned int setup_possible_cpus __initdata;
 844
 845 static int __init _setup_possible_cpus(char *s)
 846 {
 847         get_option(&s, &setup_possible_cpus);
 848         return 0;
 849 }
 850 early_param("possible_cpus", _setup_possible_cpus);
 851
 852 #ifdef CONFIG_HOTPLUG_CPU
 853
 854 int __cpu_disable(void)
 855 {
 856         unsigned long cregs[16];
 857
 858         /* Handle possible pending IPIs */
 859         smp_handle_ext_call();
 860         set_cpu_online(smp_processor_id(), false);
 861         /* Disable pseudo page faults on this cpu. */
 862         pfault_fini();
 863         /* Disable interrupt sources via control register. */
 864         __ctl_store(cregs, 0, 15);
 865         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 866         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 867         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 868         __ctl_load(cregs, 0, 15);
 869         clear_cpu_flag(CIF_NOHZ_DELAY);
 870         return 0;
 871 }
 872
 873 void __cpu_die(unsigned int cpu)
 874 {
 875         struct pcpu *pcpu;
 876
 877         /* Wait until target cpu is down */
 878         pcpu = pcpu_devices + cpu;
 879         while (!pcpu_stopped(pcpu))
 880                 cpu_relax();
 881         pcpu_free_lowcore(pcpu);
 882         atomic_dec(&init_mm.context.attach_count);
 883         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 884         if (MACHINE_HAS_TLB_LC)
 885                 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 886 }
 887
 888 void __noreturn cpu_die(void)
 889 {
 890         idle_task_exit();
 891         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 892         for (;;) ;
 893 }
 894
 895 #endif /* CONFIG_HOTPLUG_CPU */
 896
 897 void __init smp_fill_possible_mask(void)
 898 {
 899         unsigned int possible, sclp_max, cpu;
 900
 901         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 902         sclp_max = min(smp_max_threads, sclp_max);
 903         sclp_max = sclp.max_cores * sclp_max ?: nr_cpu_ids;
 904         possible = setup_possible_cpus ?: nr_cpu_ids;
 905         possible = min(possible, sclp_max);
 906         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 907                 set_cpu_possible(cpu, true);
 908 }
 909
 910 void __init smp_prepare_cpus(unsigned int max_cpus)
 911 {
 912         /* request the 0x1201 emergency signal external interrupt */
 913         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 914                 panic("Couldn't request external interrupt 0x1201");
 915         /* request the 0x1202 external call external interrupt */
 916         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 917                 panic("Couldn't request external interrupt 0x1202");
 918         smp_detect_cpus();
 919 }
 920
 921 void __init smp_prepare_boot_cpu(void)
 922 {
 923         struct pcpu *pcpu = pcpu_devices;
 924
 925         pcpu->state = CPU_STATE_CONFIGURED;
 926         pcpu->address = stap();
 927         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 928         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 929         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 930         set_cpu_present(0, true);
 931         set_cpu_online(0, true);
 932 }
 933
 934 void __init smp_cpus_done(unsigned int max_cpus)
 935 {
 936 }
 937
 938 void __init smp_setup_processor_id(void)
 939 {
 940         S390_lowcore.cpu_nr = 0;
 941         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 942 }
 943
 944 /*
 945  * the frequency of the profiling timer can be changed
 946  * by writing a multiplier value into /proc/profile.
 947  *
 948  * usually you want to run this on all CPUs ;)
 949  */
 950 int setup_profiling_timer(unsigned int multiplier)
 951 {
 952         return 0;
 953 }
 954
 955 #ifdef CONFIG_HOTPLUG_CPU
 956 static ssize_t cpu_configure_show(struct device *dev,
 957                                   struct device_attribute *attr, char *buf)
 958 {
 959         ssize_t count;
 960
 961         mutex_lock(&smp_cpu_state_mutex);
 962         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 963         mutex_unlock(&smp_cpu_state_mutex);
 964         return count;
 965 }
 966
 967 static ssize_t cpu_configure_store(struct device *dev,
 968                                    struct device_attribute *attr,
 969                                    const char *buf, size_t count)
 970 {
 971         struct pcpu *pcpu;
 972         int cpu, val, rc, i;
 973         char delim;
 974
 975         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 976                 return -EINVAL;
 977         if (val != 0 && val != 1)
 978                 return -EINVAL;
 979         get_online_cpus();
 980         mutex_lock(&smp_cpu_state_mutex);
 981         rc = -EBUSY;
 982         /* disallow configuration changes of online cpus and cpu 0 */
 983         cpu = dev->id;
 984         cpu -= cpu % (smp_cpu_mtid + 1);
 985         if (cpu == 0)
 986                 goto out;
 987         for (i = 0; i <= smp_cpu_mtid; i++)
 988                 if (cpu_online(cpu + i))
 989                         goto out;
 990         pcpu = pcpu_devices + cpu;
 991         rc = 0;
 992         switch (val) {
 993         case 0:
 994                 if (pcpu->state != CPU_STATE_CONFIGURED)
 995                         break;
 996                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
 997                 if (rc)
 998                         break;
 999                 for (i = 0; i <= smp_cpu_mtid; i++) {
1000                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1001                                 continue;
1002                         pcpu[i].state = CPU_STATE_STANDBY;
1003                         smp_cpu_set_polarization(cpu + i,
1004                                                  POLARIZATION_UNKNOWN);
1005                 }
1006                 topology_expect_change();
1007                 break;
1008         case 1:
1009                 if (pcpu->state != CPU_STATE_STANDBY)
1010                         break;
1011                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1012                 if (rc)
1013                         break;
1014                 for (i = 0; i <= smp_cpu_mtid; i++) {
1015                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1016                                 continue;
1017                         pcpu[i].state = CPU_STATE_CONFIGURED;
1018                         smp_cpu_set_polarization(cpu + i,
1019                                                  POLARIZATION_UNKNOWN);
1020                 }
1021                 topology_expect_change();
1022                 break;
1023         default:
1024                 break;
1025         }
1026 out:
1027         mutex_unlock(&smp_cpu_state_mutex);
1028         put_online_cpus();
1029         return rc ? rc : count;
1030 }
1031 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1032 #endif /* CONFIG_HOTPLUG_CPU */
1033
1034 static ssize_t show_cpu_address(struct device *dev,
1035                                 struct device_attribute *attr, char *buf)
1036 {
1037         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1038 }
1039 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1040
1041 static struct attribute *cpu_common_attrs[] = {
1042 #ifdef CONFIG_HOTPLUG_CPU
1043         &dev_attr_configure.attr,
1044 #endif
1045         &dev_attr_address.attr,
1046         NULL,
1047 };
1048
1049 static struct attribute_group cpu_common_attr_group = {
1050         .attrs = cpu_common_attrs,
1051 };
1052
1053 static struct attribute *cpu_online_attrs[] = {
1054         &dev_attr_idle_count.attr,
1055         &dev_attr_idle_time_us.attr,
1056         NULL,
1057 };
1058
1059 static struct attribute_group cpu_online_attr_group = {
1060         .attrs = cpu_online_attrs,
1061 };
1062
1063 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
1064                           void *hcpu)
1065 {
1066         unsigned int cpu = (unsigned int)(long)hcpu;
1067         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1068         int err = 0;
1069
1070         switch (action & ~CPU_TASKS_FROZEN) {
1071         case CPU_ONLINE:
1072                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1073                 break;
1074         case CPU_DEAD:
1075                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1076                 break;
1077         }
1078         return notifier_from_errno(err);
1079 }
1080
1081 static int smp_add_present_cpu(int cpu)
1082 {
1083         struct device *s;
1084         struct cpu *c;
1085         int rc;
1086
1087         c = kzalloc(sizeof(*c), GFP_KERNEL);
1088         if (!c)
1089                 return -ENOMEM;
1090         per_cpu(cpu_device, cpu) = c;
1091         s = &c->dev;
1092         c->hotpluggable = 1;
1093         rc = register_cpu(c, cpu);
1094         if (rc)
1095                 goto out;
1096         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1097         if (rc)
1098                 goto out_cpu;
1099         if (cpu_online(cpu)) {
1100                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1101                 if (rc)
1102                         goto out_online;
1103         }
1104         rc = topology_cpu_init(c);
1105         if (rc)
1106                 goto out_topology;
1107         return 0;
1108
1109 out_topology:
1110         if (cpu_online(cpu))
1111                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1112 out_online:
1113         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1114 out_cpu:
1115 #ifdef CONFIG_HOTPLUG_CPU
1116         unregister_cpu(c);
1117 #endif
1118 out:
1119         return rc;
1120 }
1121
1122 #ifdef CONFIG_HOTPLUG_CPU
1123
1124 int __ref smp_rescan_cpus(void)
1125 {
1126         struct sclp_core_info *info;
1127         int nr;
1128
1129         info = smp_get_core_info();
1130         if (!info)
1131                 return -ENOMEM;
1132         get_online_cpus();
1133         mutex_lock(&smp_cpu_state_mutex);
1134         nr = __smp_rescan_cpus(info, 1);
1135         mutex_unlock(&smp_cpu_state_mutex);
1136         put_online_cpus();
1137         kfree(info);
1138         if (nr)
1139                 topology_schedule_update();
1140         return 0;
1141 }
1142
1143 static ssize_t __ref rescan_store(struct device *dev,
1144                                   struct device_attribute *attr,
1145                                   const char *buf,
1146                                   size_t count)
1147 {
1148         int rc;
1149
1150         rc = smp_rescan_cpus();
1151         return rc ? rc : count;
1152 }
1153 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1154 #endif /* CONFIG_HOTPLUG_CPU */
1155
1156 static int __init s390_smp_init(void)
1157 {
1158         int cpu, rc = 0;
1159
1160 #ifdef CONFIG_HOTPLUG_CPU
1161         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1162         if (rc)
1163                 return rc;
1164 #endif
1165         cpu_notifier_register_begin();
1166         for_each_present_cpu(cpu) {
1167                 rc = smp_add_present_cpu(cpu);
1168                 if (rc)
1169                         goto out;
1170         }
1171
1172         __hotcpu_notifier(smp_cpu_notify, 0);
1173
1174 out:
1175         cpu_notifier_register_done();
1176         return rc;
1177 }
1178 subsys_initcall(s390_smp_init);