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->ftrace_func = S390_lowcore.ftrace_func;
 240         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 241         __ctl_store(lc->cregs_save_area, 0, 15);
 242         save_access_regs((unsigned int *) lc->access_regs_save_area);
 243         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 244                MAX_FACILITY_BIT/8);
 245 }
 246
 247 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 248 {
 249         struct _lowcore *lc = pcpu->lowcore;
 250         struct thread_info *ti = task_thread_info(tsk);
 251
 252         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 253                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 254         lc->thread_info = (unsigned long) task_thread_info(tsk);
 255         lc->current_task = (unsigned long) tsk;
 256         lc->user_timer = ti->user_timer;
 257         lc->system_timer = ti->system_timer;
 258         lc->steal_timer = 0;
 259 }
 260
 261 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 262 {
 263         struct _lowcore *lc = pcpu->lowcore;
 264
 265         lc->restart_stack = lc->kernel_stack;
 266         lc->restart_fn = (unsigned long) func;
 267         lc->restart_data = (unsigned long) data;
 268         lc->restart_source = -1UL;
 269         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 270 }
 271
 272 /*
 273  * Call function via PSW restart on pcpu and stop the current cpu.
 274  */
 275 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 276                           void *data, unsigned long stack)
 277 {
 278         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 279         unsigned long source_cpu = stap();
 280
 281         __load_psw_mask(PSW_KERNEL_BITS);
 282         if (pcpu->address == source_cpu)
 283                 func(data);     /* should not return */
 284         /* Stop target cpu (if func returns this stops the current cpu). */
 285         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 286         /* Restart func on the target cpu and stop the current cpu. */
 287         mem_assign_absolute(lc->restart_stack, stack);
 288         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 289         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 290         mem_assign_absolute(lc->restart_source, source_cpu);
 291         asm volatile(
 292                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 293                 "       brc     2,0b    # busy, try again\n"
 294                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 295                 "       brc     2,1b    # busy, try again\n"
 296                 : : "d" (pcpu->address), "d" (source_cpu),
 297                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 298                 : "0", "1", "cc");
 299         for (;;) ;
 300 }
 301
 302 /*
 303  * Call function on an online CPU.
 304  */
 305 void smp_call_online_cpu(void (*func)(void *), void *data)
 306 {
 307         struct pcpu *pcpu;
 308
 309         /* Use the current cpu if it is online. */
 310         pcpu = pcpu_find_address(cpu_online_mask, stap());
 311         if (!pcpu)
 312                 /* Use the first online cpu. */
 313                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 314         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 315 }
 316
 317 /*
 318  * Call function on the ipl CPU.
 319  */
 320 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 321 {
 322         pcpu_delegate(&pcpu_devices[0], func, data,
 323                       pcpu_devices->panic_stack + PAGE_SIZE);
 324 }
 325
 326 int smp_find_processor_id(u16 address)
 327 {
 328         int cpu;
 329
 330         for_each_present_cpu(cpu)
 331                 if (pcpu_devices[cpu].address == address)
 332                         return cpu;
 333         return -1;
 334 }
 335
 336 int smp_vcpu_scheduled(int cpu)
 337 {
 338         return pcpu_running(pcpu_devices + cpu);
 339 }
 340
 341 void smp_yield_cpu(int cpu)
 342 {
 343         if (MACHINE_HAS_DIAG9C)
 344                 asm volatile("diag %0,0,0x9c"
 345                              : : "d" (pcpu_devices[cpu].address));
 346         else if (MACHINE_HAS_DIAG44)
 347                 asm volatile("diag 0,0,0x44");
 348 }
 349
 350 /*
 351  * Send cpus emergency shutdown signal. This gives the cpus the
 352  * opportunity to complete outstanding interrupts.
 353  */
 354 static void smp_emergency_stop(cpumask_t *cpumask)
 355 {
 356         u64 end;
 357         int cpu;
 358
 359         end = get_tod_clock() + (1000000UL << 12);
 360         for_each_cpu(cpu, cpumask) {
 361                 struct pcpu *pcpu = pcpu_devices + cpu;
 362                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 363                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 364                                    0, NULL) == SIGP_CC_BUSY &&
 365                        get_tod_clock() < end)
 366                         cpu_relax();
 367         }
 368         while (get_tod_clock() < end) {
 369                 for_each_cpu(cpu, cpumask)
 370                         if (pcpu_stopped(pcpu_devices + cpu))
 371                                 cpumask_clear_cpu(cpu, cpumask);
 372                 if (cpumask_empty(cpumask))
 373                         break;
 374                 cpu_relax();
 375         }
 376 }
 377
 378 /*
 379  * Stop all cpus but the current one.
 380  */
 381 void smp_send_stop(void)
 382 {
 383         cpumask_t cpumask;
 384         int cpu;
 385
 386         /* Disable all interrupts/machine checks */
 387         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 388         trace_hardirqs_off();
 389
 390         debug_set_critical();
 391         cpumask_copy(&cpumask, cpu_online_mask);
 392         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 393
 394         if (oops_in_progress)
 395                 smp_emergency_stop(&cpumask);
 396
 397         /* stop all processors */
 398         for_each_cpu(cpu, &cpumask) {
 399                 struct pcpu *pcpu = pcpu_devices + cpu;
 400                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 401                 while (!pcpu_stopped(pcpu))
 402                         cpu_relax();
 403         }
 404 }
 405
 406 /*
 407  * This is the main routine where commands issued by other
 408  * cpus are handled.
 409  */
 410 static void smp_handle_ext_call(void)
 411 {
 412         unsigned long bits;
 413
 414         /* handle bit signal external calls */
 415         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 416         if (test_bit(ec_stop_cpu, &bits))
 417                 smp_stop_cpu();
 418         if (test_bit(ec_schedule, &bits))
 419                 scheduler_ipi();
 420         if (test_bit(ec_call_function_single, &bits))
 421                 generic_smp_call_function_single_interrupt();
 422 }
 423
 424 static void do_ext_call_interrupt(struct ext_code ext_code,
 425                                   unsigned int param32, unsigned long param64)
 426 {
 427         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 428         smp_handle_ext_call();
 429 }
 430
 431 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 432 {
 433         int cpu;
 434
 435         for_each_cpu(cpu, mask)
 436                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 437 }
 438
 439 void arch_send_call_function_single_ipi(int cpu)
 440 {
 441         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 442 }
 443
 444 #ifndef CONFIG_64BIT
 445 /*
 446  * this function sends a 'purge tlb' signal to another CPU.
 447  */
 448 static void smp_ptlb_callback(void *info)
 449 {
 450         __tlb_flush_local();
 451 }
 452
 453 void smp_ptlb_all(void)
 454 {
 455         on_each_cpu(smp_ptlb_callback, NULL, 1);
 456 }
 457 EXPORT_SYMBOL(smp_ptlb_all);
 458 #endif /* ! CONFIG_64BIT */
 459
 460 /*
 461  * this function sends a 'reschedule' IPI to another CPU.
 462  * it goes straight through and wastes no time serializing
 463  * anything. Worst case is that we lose a reschedule ...
 464  */
 465 void smp_send_reschedule(int cpu)
 466 {
 467         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 468 }
 469
 470 /*
 471  * parameter area for the set/clear control bit callbacks
 472  */
 473 struct ec_creg_mask_parms {
 474         unsigned long orval;
 475         unsigned long andval;
 476         int cr;
 477 };
 478
 479 /*
 480  * callback for setting/clearing control bits
 481  */
 482 static void smp_ctl_bit_callback(void *info)
 483 {
 484         struct ec_creg_mask_parms *pp = info;
 485         unsigned long cregs[16];
 486
 487         __ctl_store(cregs, 0, 15);
 488         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 489         __ctl_load(cregs, 0, 15);
 490 }
 491
 492 /*
 493  * Set a bit in a control register of all cpus
 494  */
 495 void smp_ctl_set_bit(int cr, int bit)
 496 {
 497         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 498
 499         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 500 }
 501 EXPORT_SYMBOL(smp_ctl_set_bit);
 502
 503 /*
 504  * Clear a bit in a control register of all cpus
 505  */
 506 void smp_ctl_clear_bit(int cr, int bit)
 507 {
 508         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 509
 510         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 511 }
 512 EXPORT_SYMBOL(smp_ctl_clear_bit);
 513
 514 #ifdef CONFIG_CRASH_DUMP
 515
 516 static void __init smp_get_save_area(int cpu, u16 address)
 517 {
 518         void *lc = pcpu_devices[0].lowcore;
 519         struct save_area_ext *sa_ext;
 520         unsigned long vx_sa;
 521
 522         if (is_kdump_kernel())
 523                 return;
 524         if (!OLDMEM_BASE && (address == boot_cpu_address ||
 525                              ipl_info.type != IPL_TYPE_FCP_DUMP))
 526                 return;
 527         sa_ext = dump_save_area_create(cpu);
 528         if (!sa_ext)
 529                 panic("could not allocate memory for save area\n");
 530         if (address == boot_cpu_address) {
 531                 /* Copy the registers of the boot cpu. */
 532                 copy_oldmem_page(1, (void *) &sa_ext->sa, sizeof(sa_ext->sa),
 533                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 534                 if (MACHINE_HAS_VX)
 535                         save_vx_regs_safe(sa_ext->vx_regs);
 536                 return;
 537         }
 538         /* Get the registers of a non-boot cpu. */
 539         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
 540         memcpy_real(&sa_ext->sa, lc + SAVE_AREA_BASE, sizeof(sa_ext->sa));
 541         if (!MACHINE_HAS_VX)
 542                 return;
 543         /* Get the VX registers */
 544         vx_sa = __get_free_page(GFP_KERNEL);
 545         if (!vx_sa)
 546                 panic("could not allocate memory for VX save area\n");
 547         __pcpu_sigp_relax(address, SIGP_STORE_ADDITIONAL_STATUS, vx_sa, NULL);
 548         memcpy(sa_ext->vx_regs, (void *) vx_sa, sizeof(sa_ext->vx_regs));
 549         free_page(vx_sa);
 550 }
 551
 552 int smp_store_status(int cpu)
 553 {
 554         unsigned long vx_sa;
 555         struct pcpu *pcpu;
 556
 557         pcpu = pcpu_devices + cpu;
 558         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
 559                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
 560                 return -EIO;
 561         if (!MACHINE_HAS_VX)
 562                 return 0;
 563         vx_sa = __pa(pcpu->lowcore->vector_save_area_addr);
 564         __pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 565                           vx_sa, NULL);
 566         return 0;
 567 }
 568
 569 #else /* CONFIG_CRASH_DUMP */
 570
 571 static inline void smp_get_save_area(int cpu, u16 address) { }
 572
 573 #endif /* CONFIG_CRASH_DUMP */
 574
 575 void smp_cpu_set_polarization(int cpu, int val)
 576 {
 577         pcpu_devices[cpu].polarization = val;
 578 }
 579
 580 int smp_cpu_get_polarization(int cpu)
 581 {
 582         return pcpu_devices[cpu].polarization;
 583 }
 584
 585 static struct sclp_cpu_info *smp_get_cpu_info(void)
 586 {
 587         static int use_sigp_detection;
 588         struct sclp_cpu_info *info;
 589         int address;
 590
 591         info = kzalloc(sizeof(*info), GFP_KERNEL);
 592         if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
 593                 use_sigp_detection = 1;
 594                 for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
 595                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 596                             SIGP_CC_NOT_OPERATIONAL)
 597                                 continue;
 598                         info->cpu[info->configured].address = address;
 599                         info->configured++;
 600                 }
 601                 info->combined = info->configured;
 602         }
 603         return info;
 604 }
 605
 606 static int smp_add_present_cpu(int cpu);
 607
 608 static int __smp_rescan_cpus(struct sclp_cpu_info *info, int sysfs_add)
 609 {
 610         struct pcpu *pcpu;
 611         cpumask_t avail;
 612         int cpu, nr, i;
 613
 614         nr = 0;
 615         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 616         cpu = cpumask_first(&avail);
 617         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 618                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 619                         continue;
 620                 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
 621                         continue;
 622                 pcpu = pcpu_devices + cpu;
 623                 pcpu->address = info->cpu[i].address;
 624                 pcpu->state = (i >= info->configured) ?
 625                         CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 626                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 627                 set_cpu_present(cpu, true);
 628                 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 629                         set_cpu_present(cpu, false);
 630                 else
 631                         nr++;
 632                 cpu = cpumask_next(cpu, &avail);
 633         }
 634         return nr;
 635 }
 636
 637 static void __init smp_detect_cpus(void)
 638 {
 639         unsigned int cpu, c_cpus, s_cpus;
 640         struct sclp_cpu_info *info;
 641
 642         info = smp_get_cpu_info();
 643         if (!info)
 644                 panic("smp_detect_cpus failed to allocate memory\n");
 645         if (info->has_cpu_type) {
 646                 for (cpu = 0; cpu < info->combined; cpu++) {
 647                         if (info->cpu[cpu].address != boot_cpu_address)
 648                                 continue;
 649                         /* The boot cpu dictates the cpu type. */
 650                         boot_cpu_type = info->cpu[cpu].type;
 651                         break;
 652                 }
 653         }
 654         c_cpus = s_cpus = 0;
 655         for (cpu = 0; cpu < info->combined; cpu++) {
 656                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
 657                         continue;
 658                 if (cpu < info->configured) {
 659                         smp_get_save_area(c_cpus, info->cpu[cpu].address);
 660                         c_cpus++;
 661                 } else
 662                         s_cpus++;
 663         }
 664         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 665         get_online_cpus();
 666         __smp_rescan_cpus(info, 0);
 667         put_online_cpus();
 668         kfree(info);
 669 }
 670
 671 /*
 672  *      Activate a secondary processor.
 673  */
 674 static void smp_start_secondary(void *cpuvoid)
 675 {
 676         S390_lowcore.last_update_clock = get_tod_clock();
 677         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 678         S390_lowcore.restart_fn = (unsigned long) do_restart;
 679         S390_lowcore.restart_data = 0;
 680         S390_lowcore.restart_source = -1UL;
 681         restore_access_regs(S390_lowcore.access_regs_save_area);
 682         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 683         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 684         cpu_init();
 685         preempt_disable();
 686         init_cpu_timer();
 687         vtime_init();
 688         pfault_init();
 689         notify_cpu_starting(smp_processor_id());
 690         set_cpu_online(smp_processor_id(), true);
 691         inc_irq_stat(CPU_RST);
 692         local_irq_enable();
 693         cpu_startup_entry(CPUHP_ONLINE);
 694 }
 695
 696 /* Upping and downing of CPUs */
 697 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 698 {
 699         struct pcpu *pcpu;
 700         int rc;
 701
 702         pcpu = pcpu_devices + cpu;
 703         if (pcpu->state != CPU_STATE_CONFIGURED)
 704                 return -EIO;
 705         if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
 706             SIGP_CC_ORDER_CODE_ACCEPTED)
 707                 return -EIO;
 708
 709         rc = pcpu_alloc_lowcore(pcpu, cpu);
 710         if (rc)
 711                 return rc;
 712         pcpu_prepare_secondary(pcpu, cpu);
 713         pcpu_attach_task(pcpu, tidle);
 714         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 715         while (!cpu_online(cpu))
 716                 cpu_relax();
 717         return 0;
 718 }
 719
 720 static unsigned int setup_possible_cpus __initdata;
 721
 722 static int __init _setup_possible_cpus(char *s)
 723 {
 724         get_option(&s, &setup_possible_cpus);
 725         return 0;
 726 }
 727 early_param("possible_cpus", _setup_possible_cpus);
 728
 729 #ifdef CONFIG_HOTPLUG_CPU
 730
 731 int __cpu_disable(void)
 732 {
 733         unsigned long cregs[16];
 734
 735         /* Handle possible pending IPIs */
 736         smp_handle_ext_call();
 737         set_cpu_online(smp_processor_id(), false);
 738         /* Disable pseudo page faults on this cpu. */
 739         pfault_fini();
 740         /* Disable interrupt sources via control register. */
 741         __ctl_store(cregs, 0, 15);
 742         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 743         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 744         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 745         __ctl_load(cregs, 0, 15);
 746         clear_cpu_flag(CIF_NOHZ_DELAY);
 747         return 0;
 748 }
 749
 750 void __cpu_die(unsigned int cpu)
 751 {
 752         struct pcpu *pcpu;
 753
 754         /* Wait until target cpu is down */
 755         pcpu = pcpu_devices + cpu;
 756         while (!pcpu_stopped(pcpu))
 757                 cpu_relax();
 758         pcpu_free_lowcore(pcpu);
 759         atomic_dec(&init_mm.context.attach_count);
 760         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 761         if (MACHINE_HAS_TLB_LC)
 762                 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 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, sclp, cpu;
 777
 778         sclp = sclp_get_max_cpu() ?: nr_cpu_ids;
 779         possible = setup_possible_cpus ?: nr_cpu_ids;
 780         possible = min(possible, sclp);
 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_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 789                 panic("Couldn't request external interrupt 0x1201");
 790         /* request the 0x1202 external call external interrupt */
 791         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 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         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 822 }
 823
 824 /*
 825  * the frequency of the profiling timer can be changed
 826  * by writing a multiplier value into /proc/profile.
 827  *
 828  * usually you want to run this on all CPUs ;)
 829  */
 830 int setup_profiling_timer(unsigned int multiplier)
 831 {
 832         return 0;
 833 }
 834
 835 #ifdef CONFIG_HOTPLUG_CPU
 836 static ssize_t cpu_configure_show(struct device *dev,
 837                                   struct device_attribute *attr, char *buf)
 838 {
 839         ssize_t count;
 840
 841         mutex_lock(&smp_cpu_state_mutex);
 842         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 843         mutex_unlock(&smp_cpu_state_mutex);
 844         return count;
 845 }
 846
 847 static ssize_t cpu_configure_store(struct device *dev,
 848                                    struct device_attribute *attr,
 849                                    const char *buf, size_t count)
 850 {
 851         struct pcpu *pcpu;
 852         int cpu, val, rc;
 853         char delim;
 854
 855         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 856                 return -EINVAL;
 857         if (val != 0 && val != 1)
 858                 return -EINVAL;
 859         get_online_cpus();
 860         mutex_lock(&smp_cpu_state_mutex);
 861         rc = -EBUSY;
 862         /* disallow configuration changes of online cpus and cpu 0 */
 863         cpu = dev->id;
 864         if (cpu_online(cpu) || cpu == 0)
 865                 goto out;
 866         pcpu = pcpu_devices + cpu;
 867         rc = 0;
 868         switch (val) {
 869         case 0:
 870                 if (pcpu->state != CPU_STATE_CONFIGURED)
 871                         break;
 872                 rc = sclp_cpu_deconfigure(pcpu->address);
 873                 if (rc)
 874                         break;
 875                 pcpu->state = CPU_STATE_STANDBY;
 876                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 877                 topology_expect_change();
 878                 break;
 879         case 1:
 880                 if (pcpu->state != CPU_STATE_STANDBY)
 881                         break;
 882                 rc = sclp_cpu_configure(pcpu->address);
 883                 if (rc)
 884                         break;
 885                 pcpu->state = CPU_STATE_CONFIGURED;
 886                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 887                 topology_expect_change();
 888                 break;
 889         default:
 890                 break;
 891         }
 892 out:
 893         mutex_unlock(&smp_cpu_state_mutex);
 894         put_online_cpus();
 895         return rc ? rc : count;
 896 }
 897 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
 898 #endif /* CONFIG_HOTPLUG_CPU */
 899
 900 static ssize_t show_cpu_address(struct device *dev,
 901                                 struct device_attribute *attr, char *buf)
 902 {
 903         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
 904 }
 905 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
 906
 907 static struct attribute *cpu_common_attrs[] = {
 908 #ifdef CONFIG_HOTPLUG_CPU
 909         &dev_attr_configure.attr,
 910 #endif
 911         &dev_attr_address.attr,
 912         NULL,
 913 };
 914
 915 static struct attribute_group cpu_common_attr_group = {
 916         .attrs = cpu_common_attrs,
 917 };
 918
 919 static struct attribute *cpu_online_attrs[] = {
 920         &dev_attr_idle_count.attr,
 921         &dev_attr_idle_time_us.attr,
 922         NULL,
 923 };
 924
 925 static struct attribute_group cpu_online_attr_group = {
 926         .attrs = cpu_online_attrs,
 927 };
 928
 929 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
 930                           void *hcpu)
 931 {
 932         unsigned int cpu = (unsigned int)(long)hcpu;
 933         struct cpu *c = pcpu_devices[cpu].cpu;
 934         struct device *s = &c->dev;
 935         int err = 0;
 936
 937         switch (action & ~CPU_TASKS_FROZEN) {
 938         case CPU_ONLINE:
 939                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 940                 break;
 941         case CPU_DEAD:
 942                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
 943                 break;
 944         }
 945         return notifier_from_errno(err);
 946 }
 947
 948 static int smp_add_present_cpu(int cpu)
 949 {
 950         struct device *s;
 951         struct cpu *c;
 952         int rc;
 953
 954         c = kzalloc(sizeof(*c), GFP_KERNEL);
 955         if (!c)
 956                 return -ENOMEM;
 957         pcpu_devices[cpu].cpu = c;
 958         s = &c->dev;
 959         c->hotpluggable = 1;
 960         rc = register_cpu(c, cpu);
 961         if (rc)
 962                 goto out;
 963         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 964         if (rc)
 965                 goto out_cpu;
 966         if (cpu_online(cpu)) {
 967                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 968                 if (rc)
 969                         goto out_online;
 970         }
 971         rc = topology_cpu_init(c);
 972         if (rc)
 973                 goto out_topology;
 974         return 0;
 975
 976 out_topology:
 977         if (cpu_online(cpu))
 978                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
 979 out_online:
 980         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
 981 out_cpu:
 982 #ifdef CONFIG_HOTPLUG_CPU
 983         unregister_cpu(c);
 984 #endif
 985 out:
 986         return rc;
 987 }
 988
 989 #ifdef CONFIG_HOTPLUG_CPU
 990
 991 int __ref smp_rescan_cpus(void)
 992 {
 993         struct sclp_cpu_info *info;
 994         int nr;
 995
 996         info = smp_get_cpu_info();
 997         if (!info)
 998                 return -ENOMEM;
 999         get_online_cpus();
1000         mutex_lock(&smp_cpu_state_mutex);
1001         nr = __smp_rescan_cpus(info, 1);
1002         mutex_unlock(&smp_cpu_state_mutex);
1003         put_online_cpus();
1004         kfree(info);
1005         if (nr)
1006                 topology_schedule_update();
1007         return 0;
1008 }
1009
1010 static ssize_t __ref rescan_store(struct device *dev,
1011                                   struct device_attribute *attr,
1012                                   const char *buf,
1013                                   size_t count)
1014 {
1015         int rc;
1016
1017         rc = smp_rescan_cpus();
1018         return rc ? rc : count;
1019 }
1020 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1021 #endif /* CONFIG_HOTPLUG_CPU */
1022
1023 static int __init s390_smp_init(void)
1024 {
1025         int cpu, rc = 0;
1026
1027 #ifdef CONFIG_HOTPLUG_CPU
1028         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1029         if (rc)
1030                 return rc;
1031 #endif
1032         cpu_notifier_register_begin();
1033         for_each_present_cpu(cpu) {
1034                 rc = smp_add_present_cpu(cpu);
1035                 if (rc)
1036                         goto out;
1037         }
1038
1039         __hotcpu_notifier(smp_cpu_notify, 0);
1040
1041 out:
1042         cpu_notifier_register_done();
1043         return rc;
1044 }
1045 subsys_initcall(s390_smp_init);