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