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/vtimer.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_single,
  53         ec_stop_cpu,
  54 };
  55
  56 enum {
  57         CPU_STATE_STANDBY,
  58         CPU_STATE_CONFIGURED,
  59 };
  60
  61 struct pcpu {
  62         struct cpu cpu;
  63         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
  64         unsigned long async_stack;      /* async stack for the cpu */
  65         unsigned long panic_stack;      /* panic stack for the cpu */
  66         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  67         int state;                      /* physical cpu state */
  68         int polarization;               /* physical polarization */
  69         u16 address;                    /* physical cpu address */
  70 };
  71
  72 static u8 boot_cpu_type;
  73 static u16 boot_cpu_address;
  74 static struct pcpu pcpu_devices[NR_CPUS];
  75
  76 /*
  77  * The smp_cpu_state_mutex must be held when changing the state or polarization
  78  * member of a pcpu data structure within the pcpu_devices arreay.
  79  */
  80 DEFINE_MUTEX(smp_cpu_state_mutex);
  81
  82 /*
  83  * Signal processor helper functions.
  84  */
  85 static inline int __pcpu_sigp(u16 addr, u8 order, u32 parm, u32 *status)
  86 {
  87         register unsigned int reg1 asm ("1") = parm;
  88         int cc;
  89
  90         asm volatile(
  91                 "       sigp    %1,%2,0(%3)\n"
  92                 "       ipm     %0\n"
  93                 "       srl     %0,28\n"
  94                 : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
  95         if (status && cc == 1)
  96                 *status = reg1;
  97         return cc;
  98 }
  99
 100 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
 101 {
 102         int cc;
 103
 104         while (1) {
 105                 cc = __pcpu_sigp(addr, order, parm, NULL);
 106                 if (cc != SIGP_CC_BUSY)
 107                         return cc;
 108                 cpu_relax();
 109         }
 110 }
 111
 112 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 113 {
 114         int cc, retry;
 115
 116         for (retry = 0; ; retry++) {
 117                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 118                 if (cc != SIGP_CC_BUSY)
 119                         break;
 120                 if (retry >= 3)
 121                         udelay(10);
 122         }
 123         return cc;
 124 }
 125
 126 static inline int pcpu_stopped(struct pcpu *pcpu)
 127 {
 128         u32 uninitialized_var(status);
 129
 130         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 131                         0, &status) != SIGP_CC_STATUS_STORED)
 132                 return 0;
 133         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 134 }
 135
 136 static inline int pcpu_running(struct pcpu *pcpu)
 137 {
 138         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 139                         0, NULL) != SIGP_CC_STATUS_STORED)
 140                 return 1;
 141         /* Status stored condition code is equivalent to cpu not running. */
 142         return 0;
 143 }
 144
 145 /*
 146  * Find struct pcpu by cpu address.
 147  */
 148 static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
 149 {
 150         int cpu;
 151
 152         for_each_cpu(cpu, mask)
 153                 if (pcpu_devices[cpu].address == address)
 154                         return pcpu_devices + cpu;
 155         return NULL;
 156 }
 157
 158 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 159 {
 160         int order;
 161
 162         set_bit(ec_bit, &pcpu->ec_mask);
 163         order = pcpu_running(pcpu) ?
 164                 SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 165         pcpu_sigp_retry(pcpu, order, 0);
 166 }
 167
 168 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 169 {
 170         struct _lowcore *lc;
 171
 172         if (pcpu != &pcpu_devices[0]) {
 173                 pcpu->lowcore = (struct _lowcore *)
 174                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 175                 pcpu->async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 176                 pcpu->panic_stack = __get_free_page(GFP_KERNEL);
 177                 if (!pcpu->lowcore || !pcpu->panic_stack || !pcpu->async_stack)
 178                         goto out;
 179         }
 180         lc = pcpu->lowcore;
 181         memcpy(lc, &S390_lowcore, 512);
 182         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 183         lc->async_stack = pcpu->async_stack + ASYNC_SIZE
 184                 - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 185         lc->panic_stack = pcpu->panic_stack + PAGE_SIZE
 186                 - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 187         lc->cpu_nr = cpu;
 188 #ifndef CONFIG_64BIT
 189         if (MACHINE_HAS_IEEE) {
 190                 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
 191                 if (!lc->extended_save_area_addr)
 192                         goto out;
 193         }
 194 #else
 195         if (vdso_alloc_per_cpu(lc))
 196                 goto out;
 197 #endif
 198         lowcore_ptr[cpu] = lc;
 199         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 200         return 0;
 201 out:
 202         if (pcpu != &pcpu_devices[0]) {
 203                 free_page(pcpu->panic_stack);
 204                 free_pages(pcpu->async_stack, ASYNC_ORDER);
 205                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 206         }
 207         return -ENOMEM;
 208 }
 209
 210 #ifdef CONFIG_HOTPLUG_CPU
 211
 212 static void pcpu_free_lowcore(struct pcpu *pcpu)
 213 {
 214         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 215         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 216 #ifndef CONFIG_64BIT
 217         if (MACHINE_HAS_IEEE) {
 218                 struct _lowcore *lc = pcpu->lowcore;
 219
 220                 free_page((unsigned long) lc->extended_save_area_addr);
 221                 lc->extended_save_area_addr = 0;
 222         }
 223 #else
 224         vdso_free_per_cpu(pcpu->lowcore);
 225 #endif
 226         if (pcpu != &pcpu_devices[0]) {
 227                 free_page(pcpu->panic_stack);
 228                 free_pages(pcpu->async_stack, ASYNC_ORDER);
 229                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 230         }
 231 }
 232
 233 #endif /* CONFIG_HOTPLUG_CPU */
 234
 235 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 236 {
 237         struct _lowcore *lc = pcpu->lowcore;
 238
 239         atomic_inc(&init_mm.context.attach_count);
 240         lc->cpu_nr = cpu;
 241         lc->percpu_offset = __per_cpu_offset[cpu];
 242         lc->kernel_asce = S390_lowcore.kernel_asce;
 243         lc->machine_flags = S390_lowcore.machine_flags;
 244         lc->ftrace_func = S390_lowcore.ftrace_func;
 245         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 246         __ctl_store(lc->cregs_save_area, 0, 15);
 247         save_access_regs((unsigned int *) lc->access_regs_save_area);
 248         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 249                MAX_FACILITY_BIT/8);
 250 }
 251
 252 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 253 {
 254         struct _lowcore *lc = pcpu->lowcore;
 255         struct thread_info *ti = task_thread_info(tsk);
 256
 257         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 258                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 259         lc->thread_info = (unsigned long) task_thread_info(tsk);
 260         lc->current_task = (unsigned long) tsk;
 261         lc->user_timer = ti->user_timer;
 262         lc->system_timer = ti->system_timer;
 263         lc->steal_timer = 0;
 264 }
 265
 266 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 267 {
 268         struct _lowcore *lc = pcpu->lowcore;
 269
 270         lc->restart_stack = lc->kernel_stack;
 271         lc->restart_fn = (unsigned long) func;
 272         lc->restart_data = (unsigned long) data;
 273         lc->restart_source = -1UL;
 274         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 275 }
 276
 277 /*
 278  * Call function via PSW restart on pcpu and stop the current cpu.
 279  */
 280 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 281                           void *data, unsigned long stack)
 282 {
 283         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 284         unsigned long source_cpu = stap();
 285
 286         __load_psw_mask(PSW_KERNEL_BITS);
 287         if (pcpu->address == source_cpu)
 288                 func(data);     /* should not return */
 289         /* Stop target cpu (if func returns this stops the current cpu). */
 290         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 291         /* Restart func on the target cpu and stop the current cpu. */
 292         mem_assign_absolute(lc->restart_stack, stack);
 293         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 294         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 295         mem_assign_absolute(lc->restart_source, source_cpu);
 296         asm volatile(
 297                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 298                 "       brc     2,0b    # busy, try again\n"
 299                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 300                 "       brc     2,1b    # busy, try again\n"
 301                 : : "d" (pcpu->address), "d" (source_cpu),
 302                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 303                 : "0", "1", "cc");
 304         for (;;) ;
 305 }
 306
 307 /*
 308  * Call function on an online CPU.
 309  */
 310 void smp_call_online_cpu(void (*func)(void *), void *data)
 311 {
 312         struct pcpu *pcpu;
 313
 314         /* Use the current cpu if it is online. */
 315         pcpu = pcpu_find_address(cpu_online_mask, stap());
 316         if (!pcpu)
 317                 /* Use the first online cpu. */
 318                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 319         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 320 }
 321
 322 /*
 323  * Call function on the ipl CPU.
 324  */
 325 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 326 {
 327         pcpu_delegate(&pcpu_devices[0], func, data,
 328                       pcpu_devices->panic_stack + PAGE_SIZE);
 329 }
 330
 331 int smp_find_processor_id(u16 address)
 332 {
 333         int cpu;
 334
 335         for_each_present_cpu(cpu)
 336                 if (pcpu_devices[cpu].address == address)
 337                         return cpu;
 338         return -1;
 339 }
 340
 341 int smp_vcpu_scheduled(int cpu)
 342 {
 343         return pcpu_running(pcpu_devices + cpu);
 344 }
 345
 346 void smp_yield(void)
 347 {
 348         if (MACHINE_HAS_DIAG44)
 349                 asm volatile("diag 0,0,0x44");
 350 }
 351
 352 void smp_yield_cpu(int cpu)
 353 {
 354         if (MACHINE_HAS_DIAG9C)
 355                 asm volatile("diag %0,0,0x9c"
 356                              : : "d" (pcpu_devices[cpu].address));
 357         else if (MACHINE_HAS_DIAG44)
 358                 asm volatile("diag 0,0,0x44");
 359 }
 360
 361 /*
 362  * Send cpus emergency shutdown signal. This gives the cpus the
 363  * opportunity to complete outstanding interrupts.
 364  */
 365 static void smp_emergency_stop(cpumask_t *cpumask)
 366 {
 367         u64 end;
 368         int cpu;
 369
 370         end = get_tod_clock() + (1000000UL << 12);
 371         for_each_cpu(cpu, cpumask) {
 372                 struct pcpu *pcpu = pcpu_devices + cpu;
 373                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 374                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 375                                    0, NULL) == SIGP_CC_BUSY &&
 376                        get_tod_clock() < end)
 377                         cpu_relax();
 378         }
 379         while (get_tod_clock() < end) {
 380                 for_each_cpu(cpu, cpumask)
 381                         if (pcpu_stopped(pcpu_devices + cpu))
 382                                 cpumask_clear_cpu(cpu, cpumask);
 383                 if (cpumask_empty(cpumask))
 384                         break;
 385                 cpu_relax();
 386         }
 387 }
 388
 389 /*
 390  * Stop all cpus but the current one.
 391  */
 392 void smp_send_stop(void)
 393 {
 394         cpumask_t cpumask;
 395         int cpu;
 396
 397         /* Disable all interrupts/machine checks */
 398         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 399         trace_hardirqs_off();
 400
 401         debug_set_critical();
 402         cpumask_copy(&cpumask, cpu_online_mask);
 403         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 404
 405         if (oops_in_progress)
 406                 smp_emergency_stop(&cpumask);
 407
 408         /* stop all processors */
 409         for_each_cpu(cpu, &cpumask) {
 410                 struct pcpu *pcpu = pcpu_devices + cpu;
 411                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 412                 while (!pcpu_stopped(pcpu))
 413                         cpu_relax();
 414         }
 415 }
 416
 417 /*
 418  * Stop the current cpu.
 419  */
 420 void smp_stop_cpu(void)
 421 {
 422         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 423         for (;;) ;
 424 }
 425
 426 /*
 427  * This is the main routine where commands issued by other
 428  * cpus are handled.
 429  */
 430 static void smp_handle_ext_call(void)
 431 {
 432         unsigned long bits;
 433
 434         /* handle bit signal external calls */
 435         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 436         if (test_bit(ec_stop_cpu, &bits))
 437                 smp_stop_cpu();
 438         if (test_bit(ec_schedule, &bits))
 439                 scheduler_ipi();
 440         if (test_bit(ec_call_function_single, &bits))
 441                 generic_smp_call_function_single_interrupt();
 442 }
 443
 444 static void do_ext_call_interrupt(struct ext_code ext_code,
 445                                   unsigned int param32, unsigned long param64)
 446 {
 447         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 448         smp_handle_ext_call();
 449 }
 450
 451 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 452 {
 453         int cpu;
 454
 455         for_each_cpu(cpu, mask)
 456                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 457 }
 458
 459 void arch_send_call_function_single_ipi(int cpu)
 460 {
 461         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 462 }
 463
 464 #ifndef CONFIG_64BIT
 465 /*
 466  * this function sends a 'purge tlb' signal to another CPU.
 467  */
 468 static void smp_ptlb_callback(void *info)
 469 {
 470         __tlb_flush_local();
 471 }
 472
 473 void smp_ptlb_all(void)
 474 {
 475         on_each_cpu(smp_ptlb_callback, NULL, 1);
 476 }
 477 EXPORT_SYMBOL(smp_ptlb_all);
 478 #endif /* ! CONFIG_64BIT */
 479
 480 /*
 481  * this function sends a 'reschedule' IPI to another CPU.
 482  * it goes straight through and wastes no time serializing
 483  * anything. Worst case is that we lose a reschedule ...
 484  */
 485 void smp_send_reschedule(int cpu)
 486 {
 487         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 488 }
 489
 490 /*
 491  * parameter area for the set/clear control bit callbacks
 492  */
 493 struct ec_creg_mask_parms {
 494         unsigned long orval;
 495         unsigned long andval;
 496         int cr;
 497 };
 498
 499 /*
 500  * callback for setting/clearing control bits
 501  */
 502 static void smp_ctl_bit_callback(void *info)
 503 {
 504         struct ec_creg_mask_parms *pp = info;
 505         unsigned long cregs[16];
 506
 507         __ctl_store(cregs, 0, 15);
 508         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 509         __ctl_load(cregs, 0, 15);
 510 }
 511
 512 /*
 513  * Set a bit in a control register of all cpus
 514  */
 515 void smp_ctl_set_bit(int cr, int bit)
 516 {
 517         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 518
 519         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 520 }
 521 EXPORT_SYMBOL(smp_ctl_set_bit);
 522
 523 /*
 524  * Clear a bit in a control register of all cpus
 525  */
 526 void smp_ctl_clear_bit(int cr, int bit)
 527 {
 528         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 529
 530         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 531 }
 532 EXPORT_SYMBOL(smp_ctl_clear_bit);
 533
 534 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
 535
 536 static void __init smp_get_save_area(int cpu, u16 address)
 537 {
 538         void *lc = pcpu_devices[0].lowcore;
 539         struct save_area *save_area;
 540
 541         if (is_kdump_kernel())
 542                 return;
 543         if (!OLDMEM_BASE && (address == boot_cpu_address ||
 544                              ipl_info.type != IPL_TYPE_FCP_DUMP))
 545                 return;
 546         save_area = dump_save_area_create(cpu);
 547         if (!save_area)
 548                 panic("could not allocate memory for save area\n");
 549 #ifdef CONFIG_CRASH_DUMP
 550         if (address == boot_cpu_address) {
 551                 /* Copy the registers of the boot cpu. */
 552                 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
 553                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 554                 return;
 555         }
 556 #endif
 557         /* Get the registers of a non-boot cpu. */
 558         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
 559         memcpy_real(save_area, lc + SAVE_AREA_BASE, sizeof(*save_area));
 560 }
 561
 562 int smp_store_status(int cpu)
 563 {
 564         struct pcpu *pcpu;
 565
 566         pcpu = pcpu_devices + cpu;
 567         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
 568                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
 569                 return -EIO;
 570         return 0;
 571 }
 572
 573 #else /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
 574
 575 static inline void smp_get_save_area(int cpu, u16 address) { }
 576
 577 #endif /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
 578
 579 void smp_cpu_set_polarization(int cpu, int val)
 580 {
 581         pcpu_devices[cpu].polarization = val;
 582 }
 583
 584 int smp_cpu_get_polarization(int cpu)
 585 {
 586         return pcpu_devices[cpu].polarization;
 587 }
 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 smp_add_present_cpu(int cpu);
 611
 612 static int __smp_rescan_cpus(struct sclp_cpu_info *info, int sysfs_add)
 613 {
 614         struct pcpu *pcpu;
 615         cpumask_t avail;
 616         int cpu, nr, i;
 617
 618         nr = 0;
 619         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 620         cpu = cpumask_first(&avail);
 621         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 622                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 623                         continue;
 624                 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
 625                         continue;
 626                 pcpu = pcpu_devices + cpu;
 627                 pcpu->address = info->cpu[i].address;
 628                 pcpu->state = (i >= info->configured) ?
 629                         CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 630                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 631                 set_cpu_present(cpu, true);
 632                 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 633                         set_cpu_present(cpu, false);
 634                 else
 635                         nr++;
 636                 cpu = cpumask_next(cpu, &avail);
 637         }
 638         return nr;
 639 }
 640
 641 static void __init smp_detect_cpus(void)
 642 {
 643         unsigned int cpu, c_cpus, s_cpus;
 644         struct sclp_cpu_info *info;
 645
 646         info = smp_get_cpu_info();
 647         if (!info)
 648                 panic("smp_detect_cpus failed to allocate memory\n");
 649         if (info->has_cpu_type) {
 650                 for (cpu = 0; cpu < info->combined; cpu++) {
 651                         if (info->cpu[cpu].address != boot_cpu_address)
 652                                 continue;
 653                         /* The boot cpu dictates the cpu type. */
 654                         boot_cpu_type = info->cpu[cpu].type;
 655                         break;
 656                 }
 657         }
 658         c_cpus = s_cpus = 0;
 659         for (cpu = 0; cpu < info->combined; cpu++) {
 660                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
 661                         continue;
 662                 if (cpu < info->configured) {
 663                         smp_get_save_area(c_cpus, info->cpu[cpu].address);
 664                         c_cpus++;
 665                 } else
 666                         s_cpus++;
 667         }
 668         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 669         get_online_cpus();
 670         __smp_rescan_cpus(info, 0);
 671         put_online_cpus();
 672         kfree(info);
 673 }
 674
 675 /*
 676  *      Activate a secondary processor.
 677  */
 678 static void smp_start_secondary(void *cpuvoid)
 679 {
 680         S390_lowcore.last_update_clock = get_tod_clock();
 681         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 682         S390_lowcore.restart_fn = (unsigned long) do_restart;
 683         S390_lowcore.restart_data = 0;
 684         S390_lowcore.restart_source = -1UL;
 685         restore_access_regs(S390_lowcore.access_regs_save_area);
 686         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 687         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 688         cpu_init();
 689         preempt_disable();
 690         init_cpu_timer();
 691         init_cpu_vtimer();
 692         pfault_init();
 693         notify_cpu_starting(smp_processor_id());
 694         set_cpu_online(smp_processor_id(), true);
 695         inc_irq_stat(CPU_RST);
 696         local_irq_enable();
 697         cpu_startup_entry(CPUHP_ONLINE);
 698 }
 699
 700 /* Upping and downing of CPUs */
 701 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 702 {
 703         struct pcpu *pcpu;
 704         int rc;
 705
 706         pcpu = pcpu_devices + cpu;
 707         if (pcpu->state != CPU_STATE_CONFIGURED)
 708                 return -EIO;
 709         if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
 710             SIGP_CC_ORDER_CODE_ACCEPTED)
 711                 return -EIO;
 712
 713         rc = pcpu_alloc_lowcore(pcpu, cpu);
 714         if (rc)
 715                 return rc;
 716         pcpu_prepare_secondary(pcpu, cpu);
 717         pcpu_attach_task(pcpu, tidle);
 718         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 719         while (!cpu_online(cpu))
 720                 cpu_relax();
 721         return 0;
 722 }
 723
 724 static unsigned int setup_possible_cpus __initdata;
 725
 726 static int __init _setup_possible_cpus(char *s)
 727 {
 728         get_option(&s, &setup_possible_cpus);
 729         return 0;
 730 }
 731 early_param("possible_cpus", _setup_possible_cpus);
 732
 733 #ifdef CONFIG_HOTPLUG_CPU
 734
 735 int __cpu_disable(void)
 736 {
 737         unsigned long cregs[16];
 738
 739         /* Handle possible pending IPIs */
 740         smp_handle_ext_call();
 741         set_cpu_online(smp_processor_id(), false);
 742         /* Disable pseudo page faults on this cpu. */
 743         pfault_fini();
 744         /* Disable interrupt sources via control register. */
 745         __ctl_store(cregs, 0, 15);
 746         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 747         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 748         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 749         __ctl_load(cregs, 0, 15);
 750         return 0;
 751 }
 752
 753 void __cpu_die(unsigned int cpu)
 754 {
 755         struct pcpu *pcpu;
 756
 757         /* Wait until target cpu is down */
 758         pcpu = pcpu_devices + cpu;
 759         while (!pcpu_stopped(pcpu))
 760                 cpu_relax();
 761         pcpu_free_lowcore(pcpu);
 762         atomic_dec(&init_mm.context.attach_count);
 763 }
 764
 765 void __noreturn cpu_die(void)
 766 {
 767         idle_task_exit();
 768         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 769         for (;;) ;
 770 }
 771
 772 #endif /* CONFIG_HOTPLUG_CPU */
 773
 774 void __init smp_fill_possible_mask(void)
 775 {
 776         unsigned int possible, cpu;
 777
 778         possible = setup_possible_cpus;
 779         if (!possible)
 780                 possible = MACHINE_IS_VM ? 64 : nr_cpu_ids;
 781         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 782                 set_cpu_possible(cpu, true);
 783 }
 784
 785 void __init smp_prepare_cpus(unsigned int max_cpus)
 786 {
 787         /* request the 0x1201 emergency signal external interrupt */
 788         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
 789                 panic("Couldn't request external interrupt 0x1201");
 790         /* request the 0x1202 external call external interrupt */
 791         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
 792                 panic("Couldn't request external interrupt 0x1202");
 793         smp_detect_cpus();
 794 }
 795
 796 void __init smp_prepare_boot_cpu(void)
 797 {
 798         struct pcpu *pcpu = pcpu_devices;
 799
 800         boot_cpu_address = stap();
 801         pcpu->state = CPU_STATE_CONFIGURED;
 802         pcpu->address = boot_cpu_address;
 803         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 804         pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE
 805                 + STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 806         pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE
 807                 + STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 808         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 809         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 810         set_cpu_present(0, true);
 811         set_cpu_online(0, true);
 812 }
 813
 814 void __init smp_cpus_done(unsigned int max_cpus)
 815 {
 816 }
 817
 818 void __init smp_setup_processor_id(void)
 819 {
 820         S390_lowcore.cpu_nr = 0;
 821 }
 822
 823 /*
 824  * the frequency of the profiling timer can be changed
 825  * by writing a multiplier value into /proc/profile.
 826  *
 827  * usually you want to run this on all CPUs ;)
 828  */
 829 int setup_profiling_timer(unsigned int multiplier)
 830 {
 831         return 0;
 832 }
 833
 834 #ifdef CONFIG_HOTPLUG_CPU
 835 static ssize_t cpu_configure_show(struct device *dev,
 836                                   struct device_attribute *attr, char *buf)
 837 {
 838         ssize_t count;
 839
 840         mutex_lock(&smp_cpu_state_mutex);
 841         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 842         mutex_unlock(&smp_cpu_state_mutex);
 843         return count;
 844 }
 845
 846 static ssize_t cpu_configure_store(struct device *dev,
 847                                    struct device_attribute *attr,
 848                                    const char *buf, size_t count)
 849 {
 850         struct pcpu *pcpu;
 851         int cpu, val, rc;
 852         char delim;
 853
 854         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 855                 return -EINVAL;
 856         if (val != 0 && val != 1)
 857                 return -EINVAL;
 858         get_online_cpus();
 859         mutex_lock(&smp_cpu_state_mutex);
 860         rc = -EBUSY;
 861         /* disallow configuration changes of online cpus and cpu 0 */
 862         cpu = dev->id;
 863         if (cpu_online(cpu) || cpu == 0)
 864                 goto out;
 865         pcpu = pcpu_devices + cpu;
 866         rc = 0;
 867         switch (val) {
 868         case 0:
 869                 if (pcpu->state != CPU_STATE_CONFIGURED)
 870                         break;
 871                 rc = sclp_cpu_deconfigure(pcpu->address);
 872                 if (rc)
 873                         break;
 874                 pcpu->state = CPU_STATE_STANDBY;
 875                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 876                 topology_expect_change();
 877                 break;
 878         case 1:
 879                 if (pcpu->state != CPU_STATE_STANDBY)
 880                         break;
 881                 rc = sclp_cpu_configure(pcpu->address);
 882                 if (rc)
 883                         break;
 884                 pcpu->state = CPU_STATE_CONFIGURED;
 885                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 886                 topology_expect_change();
 887                 break;
 888         default:
 889                 break;
 890         }
 891 out:
 892         mutex_unlock(&smp_cpu_state_mutex);
 893         put_online_cpus();
 894         return rc ? rc : count;
 895 }
 896 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
 897 #endif /* CONFIG_HOTPLUG_CPU */
 898
 899 static ssize_t show_cpu_address(struct device *dev,
 900                                 struct device_attribute *attr, char *buf)
 901 {
 902         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
 903 }
 904 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
 905
 906 static struct attribute *cpu_common_attrs[] = {
 907 #ifdef CONFIG_HOTPLUG_CPU
 908         &dev_attr_configure.attr,
 909 #endif
 910         &dev_attr_address.attr,
 911         NULL,
 912 };
 913
 914 static struct attribute_group cpu_common_attr_group = {
 915         .attrs = cpu_common_attrs,
 916 };
 917
 918 static ssize_t show_idle_count(struct device *dev,
 919                                 struct device_attribute *attr, char *buf)
 920 {
 921         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
 922         unsigned long long idle_count;
 923         unsigned int sequence;
 924
 925         do {
 926                 sequence = ACCESS_ONCE(idle->sequence);
 927                 idle_count = ACCESS_ONCE(idle->idle_count);
 928                 if (ACCESS_ONCE(idle->clock_idle_enter))
 929                         idle_count++;
 930         } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
 931         return sprintf(buf, "%llu\n", idle_count);
 932 }
 933 static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
 934
 935 static ssize_t show_idle_time(struct device *dev,
 936                                 struct device_attribute *attr, char *buf)
 937 {
 938         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
 939         unsigned long long now, idle_time, idle_enter, idle_exit;
 940         unsigned int sequence;
 941
 942         do {
 943                 now = get_tod_clock();
 944                 sequence = ACCESS_ONCE(idle->sequence);
 945                 idle_time = ACCESS_ONCE(idle->idle_time);
 946                 idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
 947                 idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
 948         } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
 949         idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
 950         return sprintf(buf, "%llu\n", idle_time >> 12);
 951 }
 952 static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 953
 954 static struct attribute *cpu_online_attrs[] = {
 955         &dev_attr_idle_count.attr,
 956         &dev_attr_idle_time_us.attr,
 957         NULL,
 958 };
 959
 960 static struct attribute_group cpu_online_attr_group = {
 961         .attrs = cpu_online_attrs,
 962 };
 963
 964 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
 965                           void *hcpu)
 966 {
 967         unsigned int cpu = (unsigned int)(long)hcpu;
 968         struct cpu *c = &pcpu_devices[cpu].cpu;
 969         struct device *s = &c->dev;
 970         int err = 0;
 971
 972         switch (action & ~CPU_TASKS_FROZEN) {
 973         case CPU_ONLINE:
 974                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 975                 break;
 976         case CPU_DEAD:
 977                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
 978                 break;
 979         }
 980         return notifier_from_errno(err);
 981 }
 982
 983 static int smp_add_present_cpu(int cpu)
 984 {
 985         struct cpu *c = &pcpu_devices[cpu].cpu;
 986         struct device *s = &c->dev;
 987         int rc;
 988
 989         c->hotpluggable = 1;
 990         rc = register_cpu(c, cpu);
 991         if (rc)
 992                 goto out;
 993         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 994         if (rc)
 995                 goto out_cpu;
 996         if (cpu_online(cpu)) {
 997                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 998                 if (rc)
 999                         goto out_online;
1000         }
1001         rc = topology_cpu_init(c);
1002         if (rc)
1003                 goto out_topology;
1004         return 0;
1005
1006 out_topology:
1007         if (cpu_online(cpu))
1008                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1009 out_online:
1010         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1011 out_cpu:
1012 #ifdef CONFIG_HOTPLUG_CPU
1013         unregister_cpu(c);
1014 #endif
1015 out:
1016         return rc;
1017 }
1018
1019 #ifdef CONFIG_HOTPLUG_CPU
1020
1021 int __ref smp_rescan_cpus(void)
1022 {
1023         struct sclp_cpu_info *info;
1024         int nr;
1025
1026         info = smp_get_cpu_info();
1027         if (!info)
1028                 return -ENOMEM;
1029         get_online_cpus();
1030         mutex_lock(&smp_cpu_state_mutex);
1031         nr = __smp_rescan_cpus(info, 1);
1032         mutex_unlock(&smp_cpu_state_mutex);
1033         put_online_cpus();
1034         kfree(info);
1035         if (nr)
1036                 topology_schedule_update();
1037         return 0;
1038 }
1039
1040 static ssize_t __ref rescan_store(struct device *dev,
1041                                   struct device_attribute *attr,
1042                                   const char *buf,
1043                                   size_t count)
1044 {
1045         int rc;
1046
1047         rc = smp_rescan_cpus();
1048         return rc ? rc : count;
1049 }
1050 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1051 #endif /* CONFIG_HOTPLUG_CPU */
1052
1053 static int __init s390_smp_init(void)
1054 {
1055         int cpu, rc;
1056
1057         hotcpu_notifier(smp_cpu_notify, 0);
1058 #ifdef CONFIG_HOTPLUG_CPU
1059         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1060         if (rc)
1061                 return rc;
1062 #endif
1063         for_each_present_cpu(cpu) {
1064                 rc = smp_add_present_cpu(cpu);
1065                 if (rc)
1066                         return rc;
1067         }
1068         return 0;
1069 }
1070 subsys_initcall(s390_smp_init);