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 <asm/asm-offsets.h>
  35 #include <asm/switch_to.h>
  36 #include <asm/facility.h>
  37 #include <asm/ipl.h>
  38 #include <asm/setup.h>
  39 #include <asm/irq.h>
  40 #include <asm/tlbflush.h>
  41 #include <asm/timer.h>
  42 #include <asm/lowcore.h>
  43 #include <asm/sclp.h>
  44 #include <asm/vdso.h>
  45 #include <asm/debug.h>
  46 #include <asm/os_info.h>
  47 #include <asm/sigp.h>
  48 #include "entry.h"
  49
  50 enum {
  51         ec_schedule = 0,
  52         ec_call_function,
  53         ec_call_function_single,
  54         ec_stop_cpu,
  55 };
  56
  57 enum {
  58         CPU_STATE_STANDBY,
  59         CPU_STATE_CONFIGURED,
  60 };
  61
  62 struct pcpu {
  63         struct cpu cpu;
  64         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
  65         unsigned long async_stack;      /* async stack for the cpu */
  66         unsigned long panic_stack;      /* panic stack for the cpu */
  67         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  68         int state;                      /* physical cpu state */
  69         u32 status;                     /* last status received via sigp */
  70         u16 address;                    /* physical cpu address */
  71 };
  72
  73 static u8 boot_cpu_type;
  74 static u16 boot_cpu_address;
  75 static struct pcpu pcpu_devices[NR_CPUS];
  76
  77 DEFINE_MUTEX(smp_cpu_state_mutex);
  78
  79 /*
  80  * Signal processor helper functions.
  81  */
  82 static inline int __pcpu_sigp(u16 addr, u8 order, u32 parm, u32 *status)
  83 {
  84         register unsigned int reg1 asm ("1") = parm;
  85         int cc;
  86
  87         asm volatile(
  88                 "       sigp    %1,%2,0(%3)\n"
  89                 "       ipm     %0\n"
  90                 "       srl     %0,28\n"
  91                 : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
  92         if (status && cc == 1)
  93                 *status = reg1;
  94         return cc;
  95 }
  96
  97 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
  98 {
  99         int cc;
 100
 101         while (1) {
 102                 cc = __pcpu_sigp(addr, order, parm, status);
 103                 if (cc != SIGP_CC_BUSY)
 104                         return cc;
 105                 cpu_relax();
 106         }
 107 }
 108
 109 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 110 {
 111         int cc, retry;
 112
 113         for (retry = 0; ; retry++) {
 114                 cc = __pcpu_sigp(pcpu->address, order, parm, &pcpu->status);
 115                 if (cc != SIGP_CC_BUSY)
 116                         break;
 117                 if (retry >= 3)
 118                         udelay(10);
 119         }
 120         return cc;
 121 }
 122
 123 static inline int pcpu_stopped(struct pcpu *pcpu)
 124 {
 125         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 126                         0, &pcpu->status) != SIGP_CC_STATUS_STORED)
 127                 return 0;
 128         return !!(pcpu->status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 129 }
 130
 131 static inline int pcpu_running(struct pcpu *pcpu)
 132 {
 133         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 134                         0, &pcpu->status) != SIGP_CC_STATUS_STORED)
 135                 return 1;
 136         /* Status stored condition code is equivalent to cpu not running. */
 137         return 0;
 138 }
 139
 140 /*
 141  * Find struct pcpu by cpu address.
 142  */
 143 static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
 144 {
 145         int cpu;
 146
 147         for_each_cpu(cpu, mask)
 148                 if (pcpu_devices[cpu].address == address)
 149                         return pcpu_devices + cpu;
 150         return NULL;
 151 }
 152
 153 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 154 {
 155         int order;
 156
 157         set_bit(ec_bit, &pcpu->ec_mask);
 158         order = pcpu_running(pcpu) ?
 159                 SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 160         pcpu_sigp_retry(pcpu, order, 0);
 161 }
 162
 163 static int __cpuinit pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 164 {
 165         struct _lowcore *lc;
 166
 167         if (pcpu != &pcpu_devices[0]) {
 168                 pcpu->lowcore = (struct _lowcore *)
 169                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 170                 pcpu->async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 171                 pcpu->panic_stack = __get_free_page(GFP_KERNEL);
 172                 if (!pcpu->lowcore || !pcpu->panic_stack || !pcpu->async_stack)
 173                         goto out;
 174         }
 175         lc = pcpu->lowcore;
 176         memcpy(lc, &S390_lowcore, 512);
 177         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 178         lc->async_stack = pcpu->async_stack + ASYNC_SIZE;
 179         lc->panic_stack = pcpu->panic_stack + PAGE_SIZE;
 180         lc->cpu_nr = cpu;
 181 #ifndef CONFIG_64BIT
 182         if (MACHINE_HAS_IEEE) {
 183                 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
 184                 if (!lc->extended_save_area_addr)
 185                         goto out;
 186         }
 187 #else
 188         if (vdso_alloc_per_cpu(lc))
 189                 goto out;
 190 #endif
 191         lowcore_ptr[cpu] = lc;
 192         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 193         return 0;
 194 out:
 195         if (pcpu != &pcpu_devices[0]) {
 196                 free_page(pcpu->panic_stack);
 197                 free_pages(pcpu->async_stack, ASYNC_ORDER);
 198                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 199         }
 200         return -ENOMEM;
 201 }
 202
 203 #ifdef CONFIG_HOTPLUG_CPU
 204
 205 static void pcpu_free_lowcore(struct pcpu *pcpu)
 206 {
 207         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 208         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 209 #ifndef CONFIG_64BIT
 210         if (MACHINE_HAS_IEEE) {
 211                 struct _lowcore *lc = pcpu->lowcore;
 212
 213                 free_page((unsigned long) lc->extended_save_area_addr);
 214                 lc->extended_save_area_addr = 0;
 215         }
 216 #else
 217         vdso_free_per_cpu(pcpu->lowcore);
 218 #endif
 219         if (pcpu != &pcpu_devices[0]) {
 220                 free_page(pcpu->panic_stack);
 221                 free_pages(pcpu->async_stack, ASYNC_ORDER);
 222                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 223         }
 224 }
 225
 226 #endif /* CONFIG_HOTPLUG_CPU */
 227
 228 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 229 {
 230         struct _lowcore *lc = pcpu->lowcore;
 231
 232         atomic_inc(&init_mm.context.attach_count);
 233         lc->cpu_nr = cpu;
 234         lc->percpu_offset = __per_cpu_offset[cpu];
 235         lc->kernel_asce = S390_lowcore.kernel_asce;
 236         lc->machine_flags = S390_lowcore.machine_flags;
 237         lc->ftrace_func = S390_lowcore.ftrace_func;
 238         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 239         __ctl_store(lc->cregs_save_area, 0, 15);
 240         save_access_regs((unsigned int *) lc->access_regs_save_area);
 241         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 242                MAX_FACILITY_BIT/8);
 243 }
 244
 245 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 246 {
 247         struct _lowcore *lc = pcpu->lowcore;
 248         struct thread_info *ti = task_thread_info(tsk);
 249
 250         lc->kernel_stack = (unsigned long) task_stack_page(tsk) + THREAD_SIZE;
 251         lc->thread_info = (unsigned long) task_thread_info(tsk);
 252         lc->current_task = (unsigned long) tsk;
 253         lc->user_timer = ti->user_timer;
 254         lc->system_timer = ti->system_timer;
 255         lc->steal_timer = 0;
 256 }
 257
 258 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 259 {
 260         struct _lowcore *lc = pcpu->lowcore;
 261
 262         lc->restart_stack = lc->kernel_stack;
 263         lc->restart_fn = (unsigned long) func;
 264         lc->restart_data = (unsigned long) data;
 265         lc->restart_source = -1UL;
 266         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 267 }
 268
 269 /*
 270  * Call function via PSW restart on pcpu and stop the current cpu.
 271  */
 272 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 273                           void *data, unsigned long stack)
 274 {
 275         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 276         unsigned long source_cpu = stap();
 277
 278         __load_psw_mask(psw_kernel_bits);
 279         if (pcpu->address == source_cpu)
 280                 func(data);     /* should not return */
 281         /* Stop target cpu (if func returns this stops the current cpu). */
 282         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 283         /* Restart func on the target cpu and stop the current cpu. */
 284         mem_assign_absolute(lc->restart_stack, stack);
 285         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 286         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 287         mem_assign_absolute(lc->restart_source, source_cpu);
 288         asm volatile(
 289                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 290                 "       brc     2,0b    # busy, try again\n"
 291                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 292                 "       brc     2,1b    # busy, try again\n"
 293                 : : "d" (pcpu->address), "d" (source_cpu),
 294                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 295                 : "0", "1", "cc");
 296         for (;;) ;
 297 }
 298
 299 /*
 300  * Call function on an online CPU.
 301  */
 302 void smp_call_online_cpu(void (*func)(void *), void *data)
 303 {
 304         struct pcpu *pcpu;
 305
 306         /* Use the current cpu if it is online. */
 307         pcpu = pcpu_find_address(cpu_online_mask, stap());
 308         if (!pcpu)
 309                 /* Use the first online cpu. */
 310                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 311         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 312 }
 313
 314 /*
 315  * Call function on the ipl CPU.
 316  */
 317 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 318 {
 319         pcpu_delegate(&pcpu_devices[0], func, data,
 320                       pcpu_devices->panic_stack + PAGE_SIZE);
 321 }
 322
 323 int smp_find_processor_id(u16 address)
 324 {
 325         int cpu;
 326
 327         for_each_present_cpu(cpu)
 328                 if (pcpu_devices[cpu].address == address)
 329                         return cpu;
 330         return -1;
 331 }
 332
 333 int smp_vcpu_scheduled(int cpu)
 334 {
 335         return pcpu_running(pcpu_devices + cpu);
 336 }
 337
 338 void smp_yield(void)
 339 {
 340         if (MACHINE_HAS_DIAG44)
 341                 asm volatile("diag 0,0,0x44");
 342 }
 343
 344 void smp_yield_cpu(int cpu)
 345 {
 346         if (MACHINE_HAS_DIAG9C)
 347                 asm volatile("diag %0,0,0x9c"
 348                              : : "d" (pcpu_devices[cpu].address));
 349         else if (MACHINE_HAS_DIAG44)
 350                 asm volatile("diag 0,0,0x44");
 351 }
 352
 353 /*
 354  * Send cpus emergency shutdown signal. This gives the cpus the
 355  * opportunity to complete outstanding interrupts.
 356  */
 357 void smp_emergency_stop(cpumask_t *cpumask)
 358 {
 359         u64 end;
 360         int cpu;
 361
 362         end = get_clock() + (1000000UL << 12);
 363         for_each_cpu(cpu, cpumask) {
 364                 struct pcpu *pcpu = pcpu_devices + cpu;
 365                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 366                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 367                                    0, NULL) == SIGP_CC_BUSY &&
 368                        get_clock() < end)
 369                         cpu_relax();
 370         }
 371         while (get_clock() < end) {
 372                 for_each_cpu(cpu, cpumask)
 373                         if (pcpu_stopped(pcpu_devices + cpu))
 374                                 cpumask_clear_cpu(cpu, cpumask);
 375                 if (cpumask_empty(cpumask))
 376                         break;
 377                 cpu_relax();
 378         }
 379 }
 380
 381 /*
 382  * Stop all cpus but the current one.
 383  */
 384 void smp_send_stop(void)
 385 {
 386         cpumask_t cpumask;
 387         int cpu;
 388
 389         /* Disable all interrupts/machine checks */
 390         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
 391         trace_hardirqs_off();
 392
 393         debug_set_critical();
 394         cpumask_copy(&cpumask, cpu_online_mask);
 395         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 396
 397         if (oops_in_progress)
 398                 smp_emergency_stop(&cpumask);
 399
 400         /* stop all processors */
 401         for_each_cpu(cpu, &cpumask) {
 402                 struct pcpu *pcpu = pcpu_devices + cpu;
 403                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 404                 while (!pcpu_stopped(pcpu))
 405                         cpu_relax();
 406         }
 407 }
 408
 409 /*
 410  * Stop the current cpu.
 411  */
 412 void smp_stop_cpu(void)
 413 {
 414         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 415         for (;;) ;
 416 }
 417
 418 /*
 419  * This is the main routine where commands issued by other
 420  * cpus are handled.
 421  */
 422 static void do_ext_call_interrupt(struct ext_code ext_code,
 423                                   unsigned int param32, unsigned long param64)
 424 {
 425         unsigned long bits;
 426         int cpu;
 427
 428         cpu = smp_processor_id();
 429         if (ext_code.code == 0x1202)
 430                 kstat_cpu(cpu).irqs[EXTINT_EXC]++;
 431         else
 432                 kstat_cpu(cpu).irqs[EXTINT_EMS]++;
 433         /*
 434          * handle bit signal external calls
 435          */
 436         bits = xchg(&pcpu_devices[cpu].ec_mask, 0);
 437
 438         if (test_bit(ec_stop_cpu, &bits))
 439                 smp_stop_cpu();
 440
 441         if (test_bit(ec_schedule, &bits))
 442                 scheduler_ipi();
 443
 444         if (test_bit(ec_call_function, &bits))
 445                 generic_smp_call_function_interrupt();
 446
 447         if (test_bit(ec_call_function_single, &bits))
 448                 generic_smp_call_function_single_interrupt();
 449
 450 }
 451
 452 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 453 {
 454         int cpu;
 455
 456         for_each_cpu(cpu, mask)
 457                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function);
 458 }
 459
 460 void arch_send_call_function_single_ipi(int cpu)
 461 {
 462         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 463 }
 464
 465 #ifndef CONFIG_64BIT
 466 /*
 467  * this function sends a 'purge tlb' signal to another CPU.
 468  */
 469 static void smp_ptlb_callback(void *info)
 470 {
 471         __tlb_flush_local();
 472 }
 473
 474 void smp_ptlb_all(void)
 475 {
 476         on_each_cpu(smp_ptlb_callback, NULL, 1);
 477 }
 478 EXPORT_SYMBOL(smp_ptlb_all);
 479 #endif /* ! CONFIG_64BIT */
 480
 481 /*
 482  * this function sends a 'reschedule' IPI to another CPU.
 483  * it goes straight through and wastes no time serializing
 484  * anything. Worst case is that we lose a reschedule ...
 485  */
 486 void smp_send_reschedule(int cpu)
 487 {
 488         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 489 }
 490
 491 /*
 492  * parameter area for the set/clear control bit callbacks
 493  */
 494 struct ec_creg_mask_parms {
 495         unsigned long orval;
 496         unsigned long andval;
 497         int cr;
 498 };
 499
 500 /*
 501  * callback for setting/clearing control bits
 502  */
 503 static void smp_ctl_bit_callback(void *info)
 504 {
 505         struct ec_creg_mask_parms *pp = info;
 506         unsigned long cregs[16];
 507
 508         __ctl_store(cregs, 0, 15);
 509         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 510         __ctl_load(cregs, 0, 15);
 511 }
 512
 513 /*
 514  * Set a bit in a control register of all cpus
 515  */
 516 void smp_ctl_set_bit(int cr, int bit)
 517 {
 518         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 519
 520         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 521 }
 522 EXPORT_SYMBOL(smp_ctl_set_bit);
 523
 524 /*
 525  * Clear a bit in a control register of all cpus
 526  */
 527 void smp_ctl_clear_bit(int cr, int bit)
 528 {
 529         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 530
 531         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 532 }
 533 EXPORT_SYMBOL(smp_ctl_clear_bit);
 534
 535 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
 536
 537 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
 538 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
 539
 540 static void __init smp_get_save_area(int cpu, u16 address)
 541 {
 542         void *lc = pcpu_devices[0].lowcore;
 543         struct save_area *save_area;
 544
 545         if (is_kdump_kernel())
 546                 return;
 547         if (!OLDMEM_BASE && (address == boot_cpu_address ||
 548                              ipl_info.type != IPL_TYPE_FCP_DUMP))
 549                 return;
 550         if (cpu >= NR_CPUS) {
 551                 pr_warning("CPU %i exceeds the maximum %i and is excluded "
 552                            "from the dump\n", cpu, NR_CPUS - 1);
 553                 return;
 554         }
 555         save_area = kmalloc(sizeof(struct save_area), GFP_KERNEL);
 556         if (!save_area)
 557                 panic("could not allocate memory for save area\n");
 558         zfcpdump_save_areas[cpu] = save_area;
 559 #ifdef CONFIG_CRASH_DUMP
 560         if (address == boot_cpu_address) {
 561                 /* Copy the registers of the boot cpu. */
 562                 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
 563                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 564                 return;
 565         }
 566 #endif
 567         /* Get the registers of a non-boot cpu. */
 568         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
 569         memcpy_real(save_area, lc + SAVE_AREA_BASE, sizeof(*save_area));
 570 }
 571
 572 int smp_store_status(int cpu)
 573 {
 574         struct pcpu *pcpu;
 575
 576         pcpu = pcpu_devices + cpu;
 577         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
 578                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
 579                 return -EIO;
 580         return 0;
 581 }
 582
 583 #else /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
 584
 585 static inline void smp_get_save_area(int cpu, u16 address) { }
 586
 587 #endif /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
 588
 589 static struct sclp_cpu_info *smp_get_cpu_info(void)
 590 {
 591         static int use_sigp_detection;
 592         struct sclp_cpu_info *info;
 593         int address;
 594
 595         info = kzalloc(sizeof(*info), GFP_KERNEL);
 596         if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
 597                 use_sigp_detection = 1;
 598                 for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
 599                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 600                             SIGP_CC_NOT_OPERATIONAL)
 601                                 continue;
 602                         info->cpu[info->configured].address = address;
 603                         info->configured++;
 604                 }
 605                 info->combined = info->configured;
 606         }
 607         return info;
 608 }
 609
 610 static int __devinit smp_add_present_cpu(int cpu);
 611
 612 static int __devinit __smp_rescan_cpus(struct sclp_cpu_info *info,
 613                                        int sysfs_add)
 614 {
 615         struct pcpu *pcpu;
 616         cpumask_t avail;
 617         int cpu, nr, i;
 618
 619         nr = 0;
 620         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 621         cpu = cpumask_first(&avail);
 622         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 623                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 624                         continue;
 625                 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
 626                         continue;
 627                 pcpu = pcpu_devices + cpu;
 628                 pcpu->address = info->cpu[i].address;
 629                 pcpu->state = (cpu >= info->configured) ?
 630                         CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 631                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 632                 set_cpu_present(cpu, true);
 633                 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 634                         set_cpu_present(cpu, false);
 635                 else
 636                         nr++;
 637                 cpu = cpumask_next(cpu, &avail);
 638         }
 639         return nr;
 640 }
 641
 642 static void __init smp_detect_cpus(void)
 643 {
 644         unsigned int cpu, c_cpus, s_cpus;
 645         struct sclp_cpu_info *info;
 646
 647         info = smp_get_cpu_info();
 648         if (!info)
 649                 panic("smp_detect_cpus failed to allocate memory\n");
 650         if (info->has_cpu_type) {
 651                 for (cpu = 0; cpu < info->combined; cpu++) {
 652                         if (info->cpu[cpu].address != boot_cpu_address)
 653                                 continue;
 654                         /* The boot cpu dictates the cpu type. */
 655                         boot_cpu_type = info->cpu[cpu].type;
 656                         break;
 657                 }
 658         }
 659         c_cpus = s_cpus = 0;
 660         for (cpu = 0; cpu < info->combined; cpu++) {
 661                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
 662                         continue;
 663                 if (cpu < info->configured) {
 664                         smp_get_save_area(c_cpus, info->cpu[cpu].address);
 665                         c_cpus++;
 666                 } else
 667                         s_cpus++;
 668         }
 669         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 670         get_online_cpus();
 671         __smp_rescan_cpus(info, 0);
 672         put_online_cpus();
 673         kfree(info);
 674 }
 675
 676 /*
 677  *      Activate a secondary processor.
 678  */
 679 static void __cpuinit smp_start_secondary(void *cpuvoid)
 680 {
 681         S390_lowcore.last_update_clock = get_clock();
 682         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 683         S390_lowcore.restart_fn = (unsigned long) do_restart;
 684         S390_lowcore.restart_data = 0;
 685         S390_lowcore.restart_source = -1UL;
 686         restore_access_regs(S390_lowcore.access_regs_save_area);
 687         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 688         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
 689         cpu_init();
 690         preempt_disable();
 691         init_cpu_timer();
 692         init_cpu_vtimer();
 693         pfault_init();
 694         notify_cpu_starting(smp_processor_id());
 695         ipi_call_lock();
 696         set_cpu_online(smp_processor_id(), true);
 697         ipi_call_unlock();
 698         local_irq_enable();
 699         /* cpu_idle will call schedule for us */
 700         cpu_idle();
 701 }
 702
 703 /* Upping and downing of CPUs */
 704 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 705 {
 706         struct pcpu *pcpu;
 707         int rc;
 708
 709         pcpu = pcpu_devices + cpu;
 710         if (pcpu->state != CPU_STATE_CONFIGURED)
 711                 return -EIO;
 712         if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
 713             SIGP_CC_ORDER_CODE_ACCEPTED)
 714                 return -EIO;
 715
 716         rc = pcpu_alloc_lowcore(pcpu, cpu);
 717         if (rc)
 718                 return rc;
 719         pcpu_prepare_secondary(pcpu, cpu);
 720         pcpu_attach_task(pcpu, tidle);
 721         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 722         while (!cpu_online(cpu))
 723                 cpu_relax();
 724         return 0;
 725 }
 726
 727 static int __init setup_possible_cpus(char *s)
 728 {
 729         int max, cpu;
 730
 731         if (kstrtoint(s, 0, &max) < 0)
 732                 return 0;
 733         init_cpu_possible(cpumask_of(0));
 734         for (cpu = 1; cpu < max && cpu < nr_cpu_ids; cpu++)
 735                 set_cpu_possible(cpu, true);
 736         return 0;
 737 }
 738 early_param("possible_cpus", setup_possible_cpus);
 739
 740 #ifdef CONFIG_HOTPLUG_CPU
 741
 742 int __cpu_disable(void)
 743 {
 744         unsigned long cregs[16];
 745
 746         set_cpu_online(smp_processor_id(), false);
 747         /* Disable pseudo page faults on this cpu. */
 748         pfault_fini();
 749         /* Disable interrupt sources via control register. */
 750         __ctl_store(cregs, 0, 15);
 751         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 752         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 753         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 754         __ctl_load(cregs, 0, 15);
 755         return 0;
 756 }
 757
 758 void __cpu_die(unsigned int cpu)
 759 {
 760         struct pcpu *pcpu;
 761
 762         /* Wait until target cpu is down */
 763         pcpu = pcpu_devices + cpu;
 764         while (!pcpu_stopped(pcpu))
 765                 cpu_relax();
 766         pcpu_free_lowcore(pcpu);
 767         atomic_dec(&init_mm.context.attach_count);
 768 }
 769
 770 void __noreturn cpu_die(void)
 771 {
 772         idle_task_exit();
 773         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 774         for (;;) ;
 775 }
 776
 777 #endif /* CONFIG_HOTPLUG_CPU */
 778
 779 void __init smp_prepare_cpus(unsigned int max_cpus)
 780 {
 781         /* request the 0x1201 emergency signal external interrupt */
 782         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
 783                 panic("Couldn't request external interrupt 0x1201");
 784         /* request the 0x1202 external call external interrupt */
 785         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
 786                 panic("Couldn't request external interrupt 0x1202");
 787         smp_detect_cpus();
 788 }
 789
 790 void __init smp_prepare_boot_cpu(void)
 791 {
 792         struct pcpu *pcpu = pcpu_devices;
 793
 794         boot_cpu_address = stap();
 795         pcpu->state = CPU_STATE_CONFIGURED;
 796         pcpu->address = boot_cpu_address;
 797         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 798         pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE;
 799         pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE;
 800         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 801         cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 802         set_cpu_present(0, true);
 803         set_cpu_online(0, true);
 804 }
 805
 806 void __init smp_cpus_done(unsigned int max_cpus)
 807 {
 808 }
 809
 810 void __init smp_setup_processor_id(void)
 811 {
 812         S390_lowcore.cpu_nr = 0;
 813 }
 814
 815 /*
 816  * the frequency of the profiling timer can be changed
 817  * by writing a multiplier value into /proc/profile.
 818  *
 819  * usually you want to run this on all CPUs ;)
 820  */
 821 int setup_profiling_timer(unsigned int multiplier)
 822 {
 823         return 0;
 824 }
 825
 826 #ifdef CONFIG_HOTPLUG_CPU
 827 static ssize_t cpu_configure_show(struct device *dev,
 828                                   struct device_attribute *attr, char *buf)
 829 {
 830         ssize_t count;
 831
 832         mutex_lock(&smp_cpu_state_mutex);
 833         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 834         mutex_unlock(&smp_cpu_state_mutex);
 835         return count;
 836 }
 837
 838 static ssize_t cpu_configure_store(struct device *dev,
 839                                    struct device_attribute *attr,
 840                                    const char *buf, size_t count)
 841 {
 842         struct pcpu *pcpu;
 843         int cpu, val, rc;
 844         char delim;
 845
 846         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 847                 return -EINVAL;
 848         if (val != 0 && val != 1)
 849                 return -EINVAL;
 850         get_online_cpus();
 851         mutex_lock(&smp_cpu_state_mutex);
 852         rc = -EBUSY;
 853         /* disallow configuration changes of online cpus and cpu 0 */
 854         cpu = dev->id;
 855         if (cpu_online(cpu) || cpu == 0)
 856                 goto out;
 857         pcpu = pcpu_devices + cpu;
 858         rc = 0;
 859         switch (val) {
 860         case 0:
 861                 if (pcpu->state != CPU_STATE_CONFIGURED)
 862                         break;
 863                 rc = sclp_cpu_deconfigure(pcpu->address);
 864                 if (rc)
 865                         break;
 866                 pcpu->state = CPU_STATE_STANDBY;
 867                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 868                 topology_expect_change();
 869                 break;
 870         case 1:
 871                 if (pcpu->state != CPU_STATE_STANDBY)
 872                         break;
 873                 rc = sclp_cpu_configure(pcpu->address);
 874                 if (rc)
 875                         break;
 876                 pcpu->state = CPU_STATE_CONFIGURED;
 877                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 878                 topology_expect_change();
 879                 break;
 880         default:
 881                 break;
 882         }
 883 out:
 884         mutex_unlock(&smp_cpu_state_mutex);
 885         put_online_cpus();
 886         return rc ? rc : count;
 887 }
 888 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
 889 #endif /* CONFIG_HOTPLUG_CPU */
 890
 891 static ssize_t show_cpu_address(struct device *dev,
 892                                 struct device_attribute *attr, char *buf)
 893 {
 894         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
 895 }
 896 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
 897
 898 static struct attribute *cpu_common_attrs[] = {
 899 #ifdef CONFIG_HOTPLUG_CPU
 900         &dev_attr_configure.attr,
 901 #endif
 902         &dev_attr_address.attr,
 903         NULL,
 904 };
 905
 906 static struct attribute_group cpu_common_attr_group = {
 907         .attrs = cpu_common_attrs,
 908 };
 909
 910 static ssize_t show_idle_count(struct device *dev,
 911                                 struct device_attribute *attr, char *buf)
 912 {
 913         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
 914         unsigned long long idle_count;
 915         unsigned int sequence;
 916
 917         do {
 918                 sequence = ACCESS_ONCE(idle->sequence);
 919                 idle_count = ACCESS_ONCE(idle->idle_count);
 920                 if (ACCESS_ONCE(idle->idle_enter))
 921                         idle_count++;
 922         } while ((sequence & 1) || (idle->sequence != sequence));
 923         return sprintf(buf, "%llu\n", idle_count);
 924 }
 925 static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
 926
 927 static ssize_t show_idle_time(struct device *dev,
 928                                 struct device_attribute *attr, char *buf)
 929 {
 930         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
 931         unsigned long long now, idle_time, idle_enter, idle_exit;
 932         unsigned int sequence;
 933
 934         do {
 935                 now = get_clock();
 936                 sequence = ACCESS_ONCE(idle->sequence);
 937                 idle_time = ACCESS_ONCE(idle->idle_time);
 938                 idle_enter = ACCESS_ONCE(idle->idle_enter);
 939                 idle_exit = ACCESS_ONCE(idle->idle_exit);
 940         } while ((sequence & 1) || (idle->sequence != sequence));
 941         idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
 942         return sprintf(buf, "%llu\n", idle_time >> 12);
 943 }
 944 static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 945
 946 static struct attribute *cpu_online_attrs[] = {
 947         &dev_attr_idle_count.attr,
 948         &dev_attr_idle_time_us.attr,
 949         NULL,
 950 };
 951
 952 static struct attribute_group cpu_online_attr_group = {
 953         .attrs = cpu_online_attrs,
 954 };
 955
 956 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
 957                                     unsigned long action, void *hcpu)
 958 {
 959         unsigned int cpu = (unsigned int)(long)hcpu;
 960         struct cpu *c = &pcpu_devices[cpu].cpu;
 961         struct device *s = &c->dev;
 962         int err = 0;
 963
 964         switch (action) {
 965         case CPU_ONLINE:
 966         case CPU_ONLINE_FROZEN:
 967                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 968                 break;
 969         case CPU_DEAD:
 970         case CPU_DEAD_FROZEN:
 971                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
 972                 break;
 973         }
 974         return notifier_from_errno(err);
 975 }
 976
 977 static struct notifier_block __cpuinitdata smp_cpu_nb = {
 978         .notifier_call = smp_cpu_notify,
 979 };
 980
 981 static int __devinit smp_add_present_cpu(int cpu)
 982 {
 983         struct cpu *c = &pcpu_devices[cpu].cpu;
 984         struct device *s = &c->dev;
 985         int rc;
 986
 987         c->hotpluggable = 1;
 988         rc = register_cpu(c, cpu);
 989         if (rc)
 990                 goto out;
 991         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 992         if (rc)
 993                 goto out_cpu;
 994         if (cpu_online(cpu)) {
 995                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 996                 if (rc)
 997                         goto out_online;
 998         }
 999         rc = topology_cpu_init(c);
1000         if (rc)
1001                 goto out_topology;
1002         return 0;
1003
1004 out_topology:
1005         if (cpu_online(cpu))
1006                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1007 out_online:
1008         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1009 out_cpu:
1010 #ifdef CONFIG_HOTPLUG_CPU
1011         unregister_cpu(c);
1012 #endif
1013 out:
1014         return rc;
1015 }
1016
1017 #ifdef CONFIG_HOTPLUG_CPU
1018
1019 int __ref smp_rescan_cpus(void)
1020 {
1021         struct sclp_cpu_info *info;
1022         int nr;
1023
1024         info = smp_get_cpu_info();
1025         if (!info)
1026                 return -ENOMEM;
1027         get_online_cpus();
1028         mutex_lock(&smp_cpu_state_mutex);
1029         nr = __smp_rescan_cpus(info, 1);
1030         mutex_unlock(&smp_cpu_state_mutex);
1031         put_online_cpus();
1032         kfree(info);
1033         if (nr)
1034                 topology_schedule_update();
1035         return 0;
1036 }
1037
1038 static ssize_t __ref rescan_store(struct device *dev,
1039                                   struct device_attribute *attr,
1040                                   const char *buf,
1041                                   size_t count)
1042 {
1043         int rc;
1044
1045         rc = smp_rescan_cpus();
1046         return rc ? rc : count;
1047 }
1048 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1049 #endif /* CONFIG_HOTPLUG_CPU */
1050
1051 static int __init s390_smp_init(void)
1052 {
1053         int cpu, rc;
1054
1055         register_cpu_notifier(&smp_cpu_nb);
1056 #ifdef CONFIG_HOTPLUG_CPU
1057         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1058         if (rc)
1059                 return rc;
1060 #endif
1061         for_each_present_cpu(cpu) {
1062                 rc = smp_add_present_cpu(cpu);
1063                 if (rc)
1064                         return rc;
1065         }
1066         return 0;
1067 }
1068 subsys_initcall(s390_smp_init);