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 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  63
  64 struct pcpu {
  65         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
  66         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  67         signed char state;              /* physical cpu state */
  68         signed char polarization;       /* physical polarization */
  69         u16 address;                    /* physical cpu address */
  70 };
  71
  72 static u8 boot_cpu_type;
  73 static struct pcpu pcpu_devices[NR_CPUS];
  74
  75 unsigned int smp_cpu_mt_shift;
  76 EXPORT_SYMBOL(smp_cpu_mt_shift);
  77
  78 unsigned int smp_cpu_mtid;
  79 EXPORT_SYMBOL(smp_cpu_mtid);
  80
  81 static unsigned int smp_max_threads __initdata = -1U;
  82
  83 static int __init early_nosmt(char *s)
  84 {
  85         smp_max_threads = 1;
  86         return 0;
  87 }
  88 early_param("nosmt", early_nosmt);
  89
  90 static int __init early_smt(char *s)
  91 {
  92         get_option(&s, &smp_max_threads);
  93         return 0;
  94 }
  95 early_param("smt", early_smt);
  96
  97 /*
  98  * The smp_cpu_state_mutex must be held when changing the state or polarization
  99  * member of a pcpu data structure within the pcpu_devices arreay.
 100  */
 101 DEFINE_MUTEX(smp_cpu_state_mutex);
 102
 103 /*
 104  * Signal processor helper functions.
 105  */
 106 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm,
 107                                     u32 *status)
 108 {
 109         int cc;
 110
 111         while (1) {
 112                 cc = __pcpu_sigp(addr, order, parm, NULL);
 113                 if (cc != SIGP_CC_BUSY)
 114                         return cc;
 115                 cpu_relax();
 116         }
 117 }
 118
 119 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 120 {
 121         int cc, retry;
 122
 123         for (retry = 0; ; retry++) {
 124                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 125                 if (cc != SIGP_CC_BUSY)
 126                         break;
 127                 if (retry >= 3)
 128                         udelay(10);
 129         }
 130         return cc;
 131 }
 132
 133 static inline int pcpu_stopped(struct pcpu *pcpu)
 134 {
 135         u32 uninitialized_var(status);
 136
 137         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 138                         0, &status) != SIGP_CC_STATUS_STORED)
 139                 return 0;
 140         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 141 }
 142
 143 static inline int pcpu_running(struct pcpu *pcpu)
 144 {
 145         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 146                         0, NULL) != SIGP_CC_STATUS_STORED)
 147                 return 1;
 148         /* Status stored condition code is equivalent to cpu not running. */
 149         return 0;
 150 }
 151
 152 /*
 153  * Find struct pcpu by cpu address.
 154  */
 155 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 156 {
 157         int cpu;
 158
 159         for_each_cpu(cpu, mask)
 160                 if (pcpu_devices[cpu].address == address)
 161                         return pcpu_devices + cpu;
 162         return NULL;
 163 }
 164
 165 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 166 {
 167         int order;
 168
 169         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 170                 return;
 171         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 172         pcpu_sigp_retry(pcpu, order, 0);
 173 }
 174
 175 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 176 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 177
 178 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 179 {
 180         unsigned long async_stack, panic_stack;
 181         struct _lowcore *lc;
 182
 183         if (pcpu != &pcpu_devices[0]) {
 184                 pcpu->lowcore = (struct _lowcore *)
 185                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 186                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 187                 panic_stack = __get_free_page(GFP_KERNEL);
 188                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 189                         goto out;
 190         } else {
 191                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 192                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 193         }
 194         lc = pcpu->lowcore;
 195         memcpy(lc, &S390_lowcore, 512);
 196         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 197         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 198         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 199         lc->cpu_nr = cpu;
 200         lc->spinlock_lockval = arch_spin_lockval(cpu);
 201 #ifndef CONFIG_64BIT
 202         if (MACHINE_HAS_IEEE) {
 203                 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
 204                 if (!lc->extended_save_area_addr)
 205                         goto out;
 206         }
 207 #else
 208         if (MACHINE_HAS_VX)
 209                 lc->vector_save_area_addr =
 210                         (unsigned long) &lc->vector_save_area;
 211         if (vdso_alloc_per_cpu(lc))
 212                 goto out;
 213 #endif
 214         lowcore_ptr[cpu] = lc;
 215         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 216         return 0;
 217 out:
 218         if (pcpu != &pcpu_devices[0]) {
 219                 free_page(panic_stack);
 220                 free_pages(async_stack, ASYNC_ORDER);
 221                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 222         }
 223         return -ENOMEM;
 224 }
 225
 226 #ifdef CONFIG_HOTPLUG_CPU
 227
 228 static void pcpu_free_lowcore(struct pcpu *pcpu)
 229 {
 230         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 231         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 232 #ifndef CONFIG_64BIT
 233         if (MACHINE_HAS_IEEE) {
 234                 struct _lowcore *lc = pcpu->lowcore;
 235
 236                 free_page((unsigned long) lc->extended_save_area_addr);
 237                 lc->extended_save_area_addr = 0;
 238         }
 239 #else
 240         vdso_free_per_cpu(pcpu->lowcore);
 241 #endif
 242         if (pcpu == &pcpu_devices[0])
 243                 return;
 244         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 245         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 246         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 247 }
 248
 249 #endif /* CONFIG_HOTPLUG_CPU */
 250
 251 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 252 {
 253         struct _lowcore *lc = pcpu->lowcore;
 254
 255         if (MACHINE_HAS_TLB_LC)
 256                 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 257         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 258         atomic_inc(&init_mm.context.attach_count);
 259         lc->cpu_nr = cpu;
 260         lc->spinlock_lockval = arch_spin_lockval(cpu);
 261         lc->percpu_offset = __per_cpu_offset[cpu];
 262         lc->kernel_asce = S390_lowcore.kernel_asce;
 263         lc->machine_flags = S390_lowcore.machine_flags;
 264         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 265         __ctl_store(lc->cregs_save_area, 0, 15);
 266         save_access_regs((unsigned int *) lc->access_regs_save_area);
 267         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 268                MAX_FACILITY_BIT/8);
 269 }
 270
 271 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 272 {
 273         struct _lowcore *lc = pcpu->lowcore;
 274         struct thread_info *ti = task_thread_info(tsk);
 275
 276         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 277                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 278         lc->thread_info = (unsigned long) task_thread_info(tsk);
 279         lc->current_task = (unsigned long) tsk;
 280         lc->user_timer = ti->user_timer;
 281         lc->system_timer = ti->system_timer;
 282         lc->steal_timer = 0;
 283 }
 284
 285 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 286 {
 287         struct _lowcore *lc = pcpu->lowcore;
 288
 289         lc->restart_stack = lc->kernel_stack;
 290         lc->restart_fn = (unsigned long) func;
 291         lc->restart_data = (unsigned long) data;
 292         lc->restart_source = -1UL;
 293         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 294 }
 295
 296 /*
 297  * Call function via PSW restart on pcpu and stop the current cpu.
 298  */
 299 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 300                           void *data, unsigned long stack)
 301 {
 302         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 303         unsigned long source_cpu = stap();
 304
 305         __load_psw_mask(PSW_KERNEL_BITS);
 306         if (pcpu->address == source_cpu)
 307                 func(data);     /* should not return */
 308         /* Stop target cpu (if func returns this stops the current cpu). */
 309         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 310         /* Restart func on the target cpu and stop the current cpu. */
 311         mem_assign_absolute(lc->restart_stack, stack);
 312         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 313         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 314         mem_assign_absolute(lc->restart_source, source_cpu);
 315         asm volatile(
 316                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 317                 "       brc     2,0b    # busy, try again\n"
 318                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 319                 "       brc     2,1b    # busy, try again\n"
 320                 : : "d" (pcpu->address), "d" (source_cpu),
 321                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 322                 : "0", "1", "cc");
 323         for (;;) ;
 324 }
 325
 326 /*
 327  * Enable additional logical cpus for multi-threading.
 328  */
 329 static int pcpu_set_smt(unsigned int mtid)
 330 {
 331         register unsigned long reg1 asm ("1") = (unsigned long) mtid;
 332         int cc;
 333
 334         if (smp_cpu_mtid == mtid)
 335                 return 0;
 336         asm volatile(
 337                 "       sigp    %1,0,%2 # sigp set multi-threading\n"
 338                 "       ipm     %0\n"
 339                 "       srl     %0,28\n"
 340                 : "=d" (cc) : "d" (reg1), "K" (SIGP_SET_MULTI_THREADING)
 341                 : "cc");
 342         if (cc == 0) {
 343                 smp_cpu_mtid = mtid;
 344                 smp_cpu_mt_shift = 0;
 345                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 346                         smp_cpu_mt_shift++;
 347                 pcpu_devices[0].address = stap();
 348         }
 349         return cc;
 350 }
 351
 352 /*
 353  * Call function on an online CPU.
 354  */
 355 void smp_call_online_cpu(void (*func)(void *), void *data)
 356 {
 357         struct pcpu *pcpu;
 358
 359         /* Use the current cpu if it is online. */
 360         pcpu = pcpu_find_address(cpu_online_mask, stap());
 361         if (!pcpu)
 362                 /* Use the first online cpu. */
 363                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 364         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 365 }
 366
 367 /*
 368  * Call function on the ipl CPU.
 369  */
 370 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 371 {
 372         pcpu_delegate(&pcpu_devices[0], func, data,
 373                       pcpu_devices->lowcore->panic_stack -
 374                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 375 }
 376
 377 int smp_find_processor_id(u16 address)
 378 {
 379         int cpu;
 380
 381         for_each_present_cpu(cpu)
 382                 if (pcpu_devices[cpu].address == address)
 383                         return cpu;
 384         return -1;
 385 }
 386
 387 int smp_vcpu_scheduled(int cpu)
 388 {
 389         return pcpu_running(pcpu_devices + cpu);
 390 }
 391
 392 void smp_yield_cpu(int cpu)
 393 {
 394         if (MACHINE_HAS_DIAG9C)
 395                 asm volatile("diag %0,0,0x9c"
 396                              : : "d" (pcpu_devices[cpu].address));
 397         else if (MACHINE_HAS_DIAG44)
 398                 asm volatile("diag 0,0,0x44");
 399 }
 400
 401 /*
 402  * Send cpus emergency shutdown signal. This gives the cpus the
 403  * opportunity to complete outstanding interrupts.
 404  */
 405 static void smp_emergency_stop(cpumask_t *cpumask)
 406 {
 407         u64 end;
 408         int cpu;
 409
 410         end = get_tod_clock() + (1000000UL << 12);
 411         for_each_cpu(cpu, cpumask) {
 412                 struct pcpu *pcpu = pcpu_devices + cpu;
 413                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 414                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 415                                    0, NULL) == SIGP_CC_BUSY &&
 416                        get_tod_clock() < end)
 417                         cpu_relax();
 418         }
 419         while (get_tod_clock() < end) {
 420                 for_each_cpu(cpu, cpumask)
 421                         if (pcpu_stopped(pcpu_devices + cpu))
 422                                 cpumask_clear_cpu(cpu, cpumask);
 423                 if (cpumask_empty(cpumask))
 424                         break;
 425                 cpu_relax();
 426         }
 427 }
 428
 429 /*
 430  * Stop all cpus but the current one.
 431  */
 432 void smp_send_stop(void)
 433 {
 434         cpumask_t cpumask;
 435         int cpu;
 436
 437         /* Disable all interrupts/machine checks */
 438         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 439         trace_hardirqs_off();
 440
 441         debug_set_critical();
 442         cpumask_copy(&cpumask, cpu_online_mask);
 443         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 444
 445         if (oops_in_progress)
 446                 smp_emergency_stop(&cpumask);
 447
 448         /* stop all processors */
 449         for_each_cpu(cpu, &cpumask) {
 450                 struct pcpu *pcpu = pcpu_devices + cpu;
 451                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 452                 while (!pcpu_stopped(pcpu))
 453                         cpu_relax();
 454         }
 455 }
 456
 457 /*
 458  * This is the main routine where commands issued by other
 459  * cpus are handled.
 460  */
 461 static void smp_handle_ext_call(void)
 462 {
 463         unsigned long bits;
 464
 465         /* handle bit signal external calls */
 466         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 467         if (test_bit(ec_stop_cpu, &bits))
 468                 smp_stop_cpu();
 469         if (test_bit(ec_schedule, &bits))
 470                 scheduler_ipi();
 471         if (test_bit(ec_call_function_single, &bits))
 472                 generic_smp_call_function_single_interrupt();
 473 }
 474
 475 static void do_ext_call_interrupt(struct ext_code ext_code,
 476                                   unsigned int param32, unsigned long param64)
 477 {
 478         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 479         smp_handle_ext_call();
 480 }
 481
 482 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 483 {
 484         int cpu;
 485
 486         for_each_cpu(cpu, mask)
 487                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 488 }
 489
 490 void arch_send_call_function_single_ipi(int cpu)
 491 {
 492         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 493 }
 494
 495 #ifndef CONFIG_64BIT
 496 /*
 497  * this function sends a 'purge tlb' signal to another CPU.
 498  */
 499 static void smp_ptlb_callback(void *info)
 500 {
 501         __tlb_flush_local();
 502 }
 503
 504 void smp_ptlb_all(void)
 505 {
 506         on_each_cpu(smp_ptlb_callback, NULL, 1);
 507 }
 508 EXPORT_SYMBOL(smp_ptlb_all);
 509 #endif /* ! CONFIG_64BIT */
 510
 511 /*
 512  * this function sends a 'reschedule' IPI to another CPU.
 513  * it goes straight through and wastes no time serializing
 514  * anything. Worst case is that we lose a reschedule ...
 515  */
 516 void smp_send_reschedule(int cpu)
 517 {
 518         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 519 }
 520
 521 /*
 522  * parameter area for the set/clear control bit callbacks
 523  */
 524 struct ec_creg_mask_parms {
 525         unsigned long orval;
 526         unsigned long andval;
 527         int cr;
 528 };
 529
 530 /*
 531  * callback for setting/clearing control bits
 532  */
 533 static void smp_ctl_bit_callback(void *info)
 534 {
 535         struct ec_creg_mask_parms *pp = info;
 536         unsigned long cregs[16];
 537
 538         __ctl_store(cregs, 0, 15);
 539         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 540         __ctl_load(cregs, 0, 15);
 541 }
 542
 543 /*
 544  * Set a bit in a control register of all cpus
 545  */
 546 void smp_ctl_set_bit(int cr, int bit)
 547 {
 548         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 549
 550         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 551 }
 552 EXPORT_SYMBOL(smp_ctl_set_bit);
 553
 554 /*
 555  * Clear a bit in a control register of all cpus
 556  */
 557 void smp_ctl_clear_bit(int cr, int bit)
 558 {
 559         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 560
 561         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 562 }
 563 EXPORT_SYMBOL(smp_ctl_clear_bit);
 564
 565 #ifdef CONFIG_CRASH_DUMP
 566
 567 static inline void __smp_store_cpu_state(int cpu, u16 address, int is_boot_cpu)
 568 {
 569         void *lc = pcpu_devices[0].lowcore;
 570         struct save_area_ext *sa_ext;
 571         unsigned long vx_sa;
 572
 573         sa_ext = dump_save_area_create(cpu);
 574         if (!sa_ext)
 575                 panic("could not allocate memory for save area\n");
 576         if (is_boot_cpu) {
 577                 /* Copy the registers of the boot CPU. */
 578                 copy_oldmem_page(1, (void *) &sa_ext->sa, sizeof(sa_ext->sa),
 579                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 580                 if (MACHINE_HAS_VX)
 581                         save_vx_regs_safe(sa_ext->vx_regs);
 582                 return;
 583         }
 584         /* Get the registers of a non-boot cpu. */
 585         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
 586         memcpy_real(&sa_ext->sa, lc + SAVE_AREA_BASE, sizeof(sa_ext->sa));
 587         if (!MACHINE_HAS_VX)
 588                 return;
 589         /* Get the VX registers */
 590         vx_sa = __get_free_page(GFP_KERNEL);
 591         if (!vx_sa)
 592                 panic("could not allocate memory for VX save area\n");
 593         __pcpu_sigp_relax(address, SIGP_STORE_ADDITIONAL_STATUS, vx_sa, NULL);
 594         memcpy(sa_ext->vx_regs, (void *) vx_sa, sizeof(sa_ext->vx_regs));
 595         free_page(vx_sa);
 596 }
 597
 598 /*
 599  * Collect CPU state of the previous, crashed system.
 600  * There are four cases:
 601  * 1) standard zfcp dump
 602  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 603  *    The state for all CPUs except the boot CPU needs to be collected
 604  *    with sigp stop-and-store-status. The boot CPU state is located in
 605  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 606  *    will allocate the save area and copy the boot CPU state from the HSA.
 607  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 608  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 609  *    The state for all CPUs except the boot CPU needs to be collected
 610  *    with sigp stop-and-store-status. The firmware or the boot-loader
 611  *    stored the registers of the boot CPU in the absolute lowcore in the
 612  *    memory of the old system.
 613  * 3) kdump and the old kernel did not store the CPU state,
 614  *    or stand-alone kdump for DASD
 615  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 616  *    The state for all CPUs except the boot CPU needs to be collected
 617  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 618  *    stored the registers of the boot CPU in the memory of the old system.
 619  * 4) kdump and the old kernel stored the CPU state
 620  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 621  *    The state of all CPUs is stored in ELF sections in the memory of the
 622  *    old system. The ELF sections are picked up by the crash_dump code
 623  *    via elfcorehdr_addr.
 624  */
 625 static void __init smp_store_cpu_states(struct sclp_cpu_info *info)
 626 {
 627         unsigned int cpu, address, i, j;
 628         int is_boot_cpu;
 629
 630         if (is_kdump_kernel())
 631                 /* Previous system stored the CPU states. Nothing to do. */
 632                 return;
 633         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 634                 /* No previous system present, normal boot. */
 635                 return;
 636         /* Set multi-threading state to the previous system. */
 637         pcpu_set_smt(sclp_get_mtid_prev());
 638         /* Collect CPU states. */
 639         cpu = 0;
 640         for (i = 0; i < info->configured; i++) {
 641                 /* Skip CPUs with different CPU type. */
 642                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 643                         continue;
 644                 for (j = 0; j <= smp_cpu_mtid; j++, cpu++) {
 645                         address = (info->cpu[i].core_id << smp_cpu_mt_shift) + j;
 646                         is_boot_cpu = (address == pcpu_devices[0].address);
 647                         if (is_boot_cpu && !OLDMEM_BASE)
 648                                 /* Skip boot CPU for standard zfcp dump. */
 649                                 continue;
 650                         /* Get state for this CPu. */
 651                         __smp_store_cpu_state(cpu, address, is_boot_cpu);
 652                 }
 653         }
 654 }
 655
 656 int smp_store_status(int cpu)
 657 {
 658         unsigned long vx_sa;
 659         struct pcpu *pcpu;
 660
 661         pcpu = pcpu_devices + cpu;
 662         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
 663                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
 664                 return -EIO;
 665         if (!MACHINE_HAS_VX)
 666                 return 0;
 667         vx_sa = __pa(pcpu->lowcore->vector_save_area_addr);
 668         __pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 669                           vx_sa, NULL);
 670         return 0;
 671 }
 672
 673 #endif /* CONFIG_CRASH_DUMP */
 674
 675 void smp_cpu_set_polarization(int cpu, int val)
 676 {
 677         pcpu_devices[cpu].polarization = val;
 678 }
 679
 680 int smp_cpu_get_polarization(int cpu)
 681 {
 682         return pcpu_devices[cpu].polarization;
 683 }
 684
 685 static struct sclp_cpu_info *smp_get_cpu_info(void)
 686 {
 687         static int use_sigp_detection;
 688         struct sclp_cpu_info *info;
 689         int address;
 690
 691         info = kzalloc(sizeof(*info), GFP_KERNEL);
 692         if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
 693                 use_sigp_detection = 1;
 694                 for (address = 0; address <= MAX_CPU_ADDRESS;
 695                      address += (1U << smp_cpu_mt_shift)) {
 696                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 697                             SIGP_CC_NOT_OPERATIONAL)
 698                                 continue;
 699                         info->cpu[info->configured].core_id =
 700                                 address >> smp_cpu_mt_shift;
 701                         info->configured++;
 702                 }
 703                 info->combined = info->configured;
 704         }
 705         return info;
 706 }
 707
 708 static int smp_add_present_cpu(int cpu);
 709
 710 static int __smp_rescan_cpus(struct sclp_cpu_info *info, int sysfs_add)
 711 {
 712         struct pcpu *pcpu;
 713         cpumask_t avail;
 714         int cpu, nr, i, j;
 715         u16 address;
 716
 717         nr = 0;
 718         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 719         cpu = cpumask_first(&avail);
 720         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 721                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 722                         continue;
 723                 address = info->cpu[i].core_id << smp_cpu_mt_shift;
 724                 for (j = 0; j <= smp_cpu_mtid; j++) {
 725                         if (pcpu_find_address(cpu_present_mask, address + j))
 726                                 continue;
 727                         pcpu = pcpu_devices + cpu;
 728                         pcpu->address = address + j;
 729                         pcpu->state =
 730                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 731                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 732                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 733                         set_cpu_present(cpu, true);
 734                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 735                                 set_cpu_present(cpu, false);
 736                         else
 737                                 nr++;
 738                         cpu = cpumask_next(cpu, &avail);
 739                         if (cpu >= nr_cpu_ids)
 740                                 break;
 741                 }
 742         }
 743         return nr;
 744 }
 745
 746 static void __init smp_detect_cpus(void)
 747 {
 748         unsigned int cpu, mtid, c_cpus, s_cpus;
 749         struct sclp_cpu_info *info;
 750         u16 address;
 751
 752         /* Get CPU information */
 753         info = smp_get_cpu_info();
 754         if (!info)
 755                 panic("smp_detect_cpus failed to allocate memory\n");
 756
 757         /* Find boot CPU type */
 758         if (info->has_cpu_type) {
 759                 address = stap();
 760                 for (cpu = 0; cpu < info->combined; cpu++)
 761                         if (info->cpu[cpu].core_id == address) {
 762                                 /* The boot cpu dictates the cpu type. */
 763                                 boot_cpu_type = info->cpu[cpu].type;
 764                                 break;
 765                         }
 766                 if (cpu >= info->combined)
 767                         panic("Could not find boot CPU type");
 768         }
 769
 770 #ifdef CONFIG_CRASH_DUMP
 771         /* Collect CPU state of previous system */
 772         smp_store_cpu_states(info);
 773 #endif
 774
 775         /* Set multi-threading state for the current system */
 776         mtid = sclp_get_mtid(boot_cpu_type);
 777         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 778         pcpu_set_smt(mtid);
 779
 780         /* Print number of CPUs */
 781         c_cpus = s_cpus = 0;
 782         for (cpu = 0; cpu < info->combined; cpu++) {
 783                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
 784                         continue;
 785                 if (cpu < info->configured)
 786                         c_cpus += smp_cpu_mtid + 1;
 787                 else
 788                         s_cpus += smp_cpu_mtid + 1;
 789         }
 790         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 791
 792         /* Add CPUs present at boot */
 793         get_online_cpus();
 794         __smp_rescan_cpus(info, 0);
 795         put_online_cpus();
 796         kfree(info);
 797 }
 798
 799 /*
 800  *      Activate a secondary processor.
 801  */
 802 static void smp_start_secondary(void *cpuvoid)
 803 {
 804         S390_lowcore.last_update_clock = get_tod_clock();
 805         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 806         S390_lowcore.restart_fn = (unsigned long) do_restart;
 807         S390_lowcore.restart_data = 0;
 808         S390_lowcore.restart_source = -1UL;
 809         restore_access_regs(S390_lowcore.access_regs_save_area);
 810         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 811         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 812         cpu_init();
 813         preempt_disable();
 814         init_cpu_timer();
 815         vtime_init();
 816         pfault_init();
 817         notify_cpu_starting(smp_processor_id());
 818         set_cpu_online(smp_processor_id(), true);
 819         inc_irq_stat(CPU_RST);
 820         local_irq_enable();
 821         cpu_startup_entry(CPUHP_ONLINE);
 822 }
 823
 824 /* Upping and downing of CPUs */
 825 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 826 {
 827         struct pcpu *pcpu;
 828         int base, i, rc;
 829
 830         pcpu = pcpu_devices + cpu;
 831         if (pcpu->state != CPU_STATE_CONFIGURED)
 832                 return -EIO;
 833         base = cpu - (cpu % (smp_cpu_mtid + 1));
 834         for (i = 0; i <= smp_cpu_mtid; i++) {
 835                 if (base + i < nr_cpu_ids)
 836                         if (cpu_online(base + i))
 837                                 break;
 838         }
 839         /*
 840          * If this is the first CPU of the core to get online
 841          * do an initial CPU reset.
 842          */
 843         if (i > smp_cpu_mtid &&
 844             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 845             SIGP_CC_ORDER_CODE_ACCEPTED)
 846                 return -EIO;
 847
 848         rc = pcpu_alloc_lowcore(pcpu, cpu);
 849         if (rc)
 850                 return rc;
 851         pcpu_prepare_secondary(pcpu, cpu);
 852         pcpu_attach_task(pcpu, tidle);
 853         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 854         while (!cpu_online(cpu))
 855                 cpu_relax();
 856         return 0;
 857 }
 858
 859 static unsigned int setup_possible_cpus __initdata;
 860
 861 static int __init _setup_possible_cpus(char *s)
 862 {
 863         get_option(&s, &setup_possible_cpus);
 864         return 0;
 865 }
 866 early_param("possible_cpus", _setup_possible_cpus);
 867
 868 #ifdef CONFIG_HOTPLUG_CPU
 869
 870 int __cpu_disable(void)
 871 {
 872         unsigned long cregs[16];
 873
 874         /* Handle possible pending IPIs */
 875         smp_handle_ext_call();
 876         set_cpu_online(smp_processor_id(), false);
 877         /* Disable pseudo page faults on this cpu. */
 878         pfault_fini();
 879         /* Disable interrupt sources via control register. */
 880         __ctl_store(cregs, 0, 15);
 881         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 882         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 883         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 884         __ctl_load(cregs, 0, 15);
 885         clear_cpu_flag(CIF_NOHZ_DELAY);
 886         return 0;
 887 }
 888
 889 void __cpu_die(unsigned int cpu)
 890 {
 891         struct pcpu *pcpu;
 892
 893         /* Wait until target cpu is down */
 894         pcpu = pcpu_devices + cpu;
 895         while (!pcpu_stopped(pcpu))
 896                 cpu_relax();
 897         pcpu_free_lowcore(pcpu);
 898         atomic_dec(&init_mm.context.attach_count);
 899         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 900         if (MACHINE_HAS_TLB_LC)
 901                 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 902 }
 903
 904 void __noreturn cpu_die(void)
 905 {
 906         idle_task_exit();
 907         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 908         for (;;) ;
 909 }
 910
 911 #endif /* CONFIG_HOTPLUG_CPU */
 912
 913 void __init smp_fill_possible_mask(void)
 914 {
 915         unsigned int possible, sclp, cpu;
 916
 917         sclp = min(smp_max_threads, sclp_get_mtid_max() + 1);
 918         sclp = sclp_get_max_cpu()*sclp ?: nr_cpu_ids;
 919         possible = setup_possible_cpus ?: nr_cpu_ids;
 920         possible = min(possible, sclp);
 921         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 922                 set_cpu_possible(cpu, true);
 923 }
 924
 925 void __init smp_prepare_cpus(unsigned int max_cpus)
 926 {
 927         /* request the 0x1201 emergency signal external interrupt */
 928         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 929                 panic("Couldn't request external interrupt 0x1201");
 930         /* request the 0x1202 external call external interrupt */
 931         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 932                 panic("Couldn't request external interrupt 0x1202");
 933         smp_detect_cpus();
 934 }
 935
 936 void __init smp_prepare_boot_cpu(void)
 937 {
 938         struct pcpu *pcpu = pcpu_devices;
 939
 940         pcpu->state = CPU_STATE_CONFIGURED;
 941         pcpu->address = stap();
 942         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 943         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 944         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 945         set_cpu_present(0, true);
 946         set_cpu_online(0, true);
 947 }
 948
 949 void __init smp_cpus_done(unsigned int max_cpus)
 950 {
 951 }
 952
 953 void __init smp_setup_processor_id(void)
 954 {
 955         S390_lowcore.cpu_nr = 0;
 956         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 957 }
 958
 959 /*
 960  * the frequency of the profiling timer can be changed
 961  * by writing a multiplier value into /proc/profile.
 962  *
 963  * usually you want to run this on all CPUs ;)
 964  */
 965 int setup_profiling_timer(unsigned int multiplier)
 966 {
 967         return 0;
 968 }
 969
 970 #ifdef CONFIG_HOTPLUG_CPU
 971 static ssize_t cpu_configure_show(struct device *dev,
 972                                   struct device_attribute *attr, char *buf)
 973 {
 974         ssize_t count;
 975
 976         mutex_lock(&smp_cpu_state_mutex);
 977         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 978         mutex_unlock(&smp_cpu_state_mutex);
 979         return count;
 980 }
 981
 982 static ssize_t cpu_configure_store(struct device *dev,
 983                                    struct device_attribute *attr,
 984                                    const char *buf, size_t count)
 985 {
 986         struct pcpu *pcpu;
 987         int cpu, val, rc, i;
 988         char delim;
 989
 990         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 991                 return -EINVAL;
 992         if (val != 0 && val != 1)
 993                 return -EINVAL;
 994         get_online_cpus();
 995         mutex_lock(&smp_cpu_state_mutex);
 996         rc = -EBUSY;
 997         /* disallow configuration changes of online cpus and cpu 0 */
 998         cpu = dev->id;
 999         cpu -= cpu % (smp_cpu_mtid + 1);
1000         if (cpu == 0)
1001                 goto out;
1002         for (i = 0; i <= smp_cpu_mtid; i++)
1003                 if (cpu_online(cpu + i))
1004                         goto out;
1005         pcpu = pcpu_devices + cpu;
1006         rc = 0;
1007         switch (val) {
1008         case 0:
1009                 if (pcpu->state != CPU_STATE_CONFIGURED)
1010                         break;
1011                 rc = sclp_cpu_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1012                 if (rc)
1013                         break;
1014                 for (i = 0; i <= smp_cpu_mtid; i++) {
1015                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1016                                 continue;
1017                         pcpu[i].state = CPU_STATE_STANDBY;
1018                         smp_cpu_set_polarization(cpu + i,
1019                                                  POLARIZATION_UNKNOWN);
1020                 }
1021                 topology_expect_change();
1022                 break;
1023         case 1:
1024                 if (pcpu->state != CPU_STATE_STANDBY)
1025                         break;
1026                 rc = sclp_cpu_configure(pcpu->address >> smp_cpu_mt_shift);
1027                 if (rc)
1028                         break;
1029                 for (i = 0; i <= smp_cpu_mtid; i++) {
1030                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1031                                 continue;
1032                         pcpu[i].state = CPU_STATE_CONFIGURED;
1033                         smp_cpu_set_polarization(cpu + i,
1034                                                  POLARIZATION_UNKNOWN);
1035                 }
1036                 topology_expect_change();
1037                 break;
1038         default:
1039                 break;
1040         }
1041 out:
1042         mutex_unlock(&smp_cpu_state_mutex);
1043         put_online_cpus();
1044         return rc ? rc : count;
1045 }
1046 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1047 #endif /* CONFIG_HOTPLUG_CPU */
1048
1049 static ssize_t show_cpu_address(struct device *dev,
1050                                 struct device_attribute *attr, char *buf)
1051 {
1052         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1053 }
1054 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1055
1056 static struct attribute *cpu_common_attrs[] = {
1057 #ifdef CONFIG_HOTPLUG_CPU
1058         &dev_attr_configure.attr,
1059 #endif
1060         &dev_attr_address.attr,
1061         NULL,
1062 };
1063
1064 static struct attribute_group cpu_common_attr_group = {
1065         .attrs = cpu_common_attrs,
1066 };
1067
1068 static struct attribute *cpu_online_attrs[] = {
1069         &dev_attr_idle_count.attr,
1070         &dev_attr_idle_time_us.attr,
1071         NULL,
1072 };
1073
1074 static struct attribute_group cpu_online_attr_group = {
1075         .attrs = cpu_online_attrs,
1076 };
1077
1078 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
1079                           void *hcpu)
1080 {
1081         unsigned int cpu = (unsigned int)(long)hcpu;
1082         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1083         int err = 0;
1084
1085         switch (action & ~CPU_TASKS_FROZEN) {
1086         case CPU_ONLINE:
1087                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1088                 break;
1089         case CPU_DEAD:
1090                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1091                 break;
1092         }
1093         return notifier_from_errno(err);
1094 }
1095
1096 static int smp_add_present_cpu(int cpu)
1097 {
1098         struct device *s;
1099         struct cpu *c;
1100         int rc;
1101
1102         c = kzalloc(sizeof(*c), GFP_KERNEL);
1103         if (!c)
1104                 return -ENOMEM;
1105         per_cpu(cpu_device, cpu) = c;
1106         s = &c->dev;
1107         c->hotpluggable = 1;
1108         rc = register_cpu(c, cpu);
1109         if (rc)
1110                 goto out;
1111         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1112         if (rc)
1113                 goto out_cpu;
1114         if (cpu_online(cpu)) {
1115                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1116                 if (rc)
1117                         goto out_online;
1118         }
1119         rc = topology_cpu_init(c);
1120         if (rc)
1121                 goto out_topology;
1122         return 0;
1123
1124 out_topology:
1125         if (cpu_online(cpu))
1126                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1127 out_online:
1128         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1129 out_cpu:
1130 #ifdef CONFIG_HOTPLUG_CPU
1131         unregister_cpu(c);
1132 #endif
1133 out:
1134         return rc;
1135 }
1136
1137 #ifdef CONFIG_HOTPLUG_CPU
1138
1139 int __ref smp_rescan_cpus(void)
1140 {
1141         struct sclp_cpu_info *info;
1142         int nr;
1143
1144         info = smp_get_cpu_info();
1145         if (!info)
1146                 return -ENOMEM;
1147         get_online_cpus();
1148         mutex_lock(&smp_cpu_state_mutex);
1149         nr = __smp_rescan_cpus(info, 1);
1150         mutex_unlock(&smp_cpu_state_mutex);
1151         put_online_cpus();
1152         kfree(info);
1153         if (nr)
1154                 topology_schedule_update();
1155         return 0;
1156 }
1157
1158 static ssize_t __ref rescan_store(struct device *dev,
1159                                   struct device_attribute *attr,
1160                                   const char *buf,
1161                                   size_t count)
1162 {
1163         int rc;
1164
1165         rc = smp_rescan_cpus();
1166         return rc ? rc : count;
1167 }
1168 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1169 #endif /* CONFIG_HOTPLUG_CPU */
1170
1171 static int __init s390_smp_init(void)
1172 {
1173         int cpu, rc = 0;
1174
1175 #ifdef CONFIG_HOTPLUG_CPU
1176         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1177         if (rc)
1178                 return rc;
1179 #endif
1180         cpu_notifier_register_begin();
1181         for_each_present_cpu(cpu) {
1182                 rc = smp_add_present_cpu(cpu);
1183                 if (rc)
1184                         goto out;
1185         }
1186
1187         __hotcpu_notifier(smp_cpu_notify, 0);
1188
1189 out:
1190         cpu_notifier_register_done();
1191         return rc;
1192 }
1193 subsys_initcall(s390_smp_init);