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/bootmem.h>
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/mm.h>
  26 #include <linux/err.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/kernel_stat.h>
  29 #include <linux/delay.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/irqflags.h>
  32 #include <linux/cpu.h>
  33 #include <linux/slab.h>
  34 #include <linux/crash_dump.h>
  35 #include <linux/memblock.h>
  36 #include <asm/asm-offsets.h>
  37 #include <asm/diag.h>
  38 #include <asm/switch_to.h>
  39 #include <asm/facility.h>
  40 #include <asm/ipl.h>
  41 #include <asm/setup.h>
  42 #include <asm/irq.h>
  43 #include <asm/tlbflush.h>
  44 #include <asm/vtimer.h>
  45 #include <asm/lowcore.h>
  46 #include <asm/sclp.h>
  47 #include <asm/vdso.h>
  48 #include <asm/debug.h>
  49 #include <asm/os_info.h>
  50 #include <asm/sigp.h>
  51 #include <asm/idle.h>
  52 #include "entry.h"
  53
  54 enum {
  55         ec_schedule = 0,
  56         ec_call_function_single,
  57         ec_stop_cpu,
  58 };
  59
  60 enum {
  61         CPU_STATE_STANDBY,
  62         CPU_STATE_CONFIGURED,
  63 };
  64
  65 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  66
  67 struct pcpu {
  68         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  69         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  70         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  71         signed char state;              /* physical cpu state */
  72         signed char polarization;       /* physical polarization */
  73         u16 address;                    /* physical cpu address */
  74 };
  75
  76 static u8 boot_core_type;
  77 static struct pcpu pcpu_devices[NR_CPUS];
  78
  79 unsigned int smp_cpu_mt_shift;
  80 EXPORT_SYMBOL(smp_cpu_mt_shift);
  81
  82 unsigned int smp_cpu_mtid;
  83 EXPORT_SYMBOL(smp_cpu_mtid);
  84
  85 #ifdef CONFIG_CRASH_DUMP
  86 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  87 #endif
  88
  89 static unsigned int smp_max_threads __initdata = -1U;
  90
  91 static int __init early_nosmt(char *s)
  92 {
  93         smp_max_threads = 1;
  94         return 0;
  95 }
  96 early_param("nosmt", early_nosmt);
  97
  98 static int __init early_smt(char *s)
  99 {
 100         get_option(&s, &smp_max_threads);
 101         return 0;
 102 }
 103 early_param("smt", early_smt);
 104
 105 /*
 106  * The smp_cpu_state_mutex must be held when changing the state or polarization
 107  * member of a pcpu data structure within the pcpu_devices arreay.
 108  */
 109 DEFINE_MUTEX(smp_cpu_state_mutex);
 110
 111 /*
 112  * Signal processor helper functions.
 113  */
 114 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 115 {
 116         int cc;
 117
 118         while (1) {
 119                 cc = __pcpu_sigp(addr, order, parm, NULL);
 120                 if (cc != SIGP_CC_BUSY)
 121                         return cc;
 122                 cpu_relax();
 123         }
 124 }
 125
 126 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 127 {
 128         int cc, retry;
 129
 130         for (retry = 0; ; retry++) {
 131                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 132                 if (cc != SIGP_CC_BUSY)
 133                         break;
 134                 if (retry >= 3)
 135                         udelay(10);
 136         }
 137         return cc;
 138 }
 139
 140 static inline int pcpu_stopped(struct pcpu *pcpu)
 141 {
 142         u32 uninitialized_var(status);
 143
 144         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 145                         0, &status) != SIGP_CC_STATUS_STORED)
 146                 return 0;
 147         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 148 }
 149
 150 static inline int pcpu_running(struct pcpu *pcpu)
 151 {
 152         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 153                         0, NULL) != SIGP_CC_STATUS_STORED)
 154                 return 1;
 155         /* Status stored condition code is equivalent to cpu not running. */
 156         return 0;
 157 }
 158
 159 /*
 160  * Find struct pcpu by cpu address.
 161  */
 162 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 163 {
 164         int cpu;
 165
 166         for_each_cpu(cpu, mask)
 167                 if (pcpu_devices[cpu].address == address)
 168                         return pcpu_devices + cpu;
 169         return NULL;
 170 }
 171
 172 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 173 {
 174         int order;
 175
 176         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 177                 return;
 178         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 179         pcpu->ec_clk = get_tod_clock_fast();
 180         pcpu_sigp_retry(pcpu, order, 0);
 181 }
 182
 183 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 184 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 185
 186 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 187 {
 188         unsigned long async_stack, panic_stack;
 189         struct lowcore *lc;
 190
 191         if (pcpu != &pcpu_devices[0]) {
 192                 pcpu->lowcore = (struct lowcore *)
 193                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 194                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 195                 panic_stack = __get_free_page(GFP_KERNEL);
 196                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 197                         goto out;
 198         } else {
 199                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 200                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 201         }
 202         lc = pcpu->lowcore;
 203         memcpy(lc, &S390_lowcore, 512);
 204         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 205         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 206         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 207         lc->cpu_nr = cpu;
 208         lc->spinlock_lockval = arch_spin_lockval(cpu);
 209         if (MACHINE_HAS_VX)
 210                 lc->vector_save_area_addr =
 211                         (unsigned long) &lc->vector_save_area;
 212         if (vdso_alloc_per_cpu(lc))
 213                 goto out;
 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         vdso_free_per_cpu(pcpu->lowcore);
 233         if (pcpu == &pcpu_devices[0])
 234                 return;
 235         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 236         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 237         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 238 }
 239
 240 #endif /* CONFIG_HOTPLUG_CPU */
 241
 242 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 243 {
 244         struct lowcore *lc = pcpu->lowcore;
 245
 246         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 247         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 248         lc->cpu_nr = cpu;
 249         lc->spinlock_lockval = arch_spin_lockval(cpu);
 250         lc->percpu_offset = __per_cpu_offset[cpu];
 251         lc->kernel_asce = S390_lowcore.kernel_asce;
 252         lc->machine_flags = S390_lowcore.machine_flags;
 253         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 254         __ctl_store(lc->cregs_save_area, 0, 15);
 255         save_access_regs((unsigned int *) lc->access_regs_save_area);
 256         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 257                MAX_FACILITY_BIT/8);
 258 }
 259
 260 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 261 {
 262         struct lowcore *lc = pcpu->lowcore;
 263
 264         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 265                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 266         lc->current_task = (unsigned long) tsk;
 267         lc->lpp = LPP_MAGIC;
 268         lc->current_pid = tsk->pid;
 269         lc->user_timer = tsk->thread.user_timer;
 270         lc->system_timer = tsk->thread.system_timer;
 271         lc->steal_timer = 0;
 272 }
 273
 274 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 275 {
 276         struct lowcore *lc = pcpu->lowcore;
 277
 278         lc->restart_stack = lc->kernel_stack;
 279         lc->restart_fn = (unsigned long) func;
 280         lc->restart_data = (unsigned long) data;
 281         lc->restart_source = -1UL;
 282         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 283 }
 284
 285 /*
 286  * Call function via PSW restart on pcpu and stop the current cpu.
 287  */
 288 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 289                           void *data, unsigned long stack)
 290 {
 291         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 292         unsigned long source_cpu = stap();
 293
 294         __load_psw_mask(PSW_KERNEL_BITS);
 295         if (pcpu->address == source_cpu)
 296                 func(data);     /* should not return */
 297         /* Stop target cpu (if func returns this stops the current cpu). */
 298         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 299         /* Restart func on the target cpu and stop the current cpu. */
 300         mem_assign_absolute(lc->restart_stack, stack);
 301         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 302         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 303         mem_assign_absolute(lc->restart_source, source_cpu);
 304         asm volatile(
 305                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 306                 "       brc     2,0b    # busy, try again\n"
 307                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 308                 "       brc     2,1b    # busy, try again\n"
 309                 : : "d" (pcpu->address), "d" (source_cpu),
 310                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 311                 : "0", "1", "cc");
 312         for (;;) ;
 313 }
 314
 315 /*
 316  * Enable additional logical cpus for multi-threading.
 317  */
 318 static int pcpu_set_smt(unsigned int mtid)
 319 {
 320         int cc;
 321
 322         if (smp_cpu_mtid == mtid)
 323                 return 0;
 324         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 325         if (cc == 0) {
 326                 smp_cpu_mtid = mtid;
 327                 smp_cpu_mt_shift = 0;
 328                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 329                         smp_cpu_mt_shift++;
 330                 pcpu_devices[0].address = stap();
 331         }
 332         return cc;
 333 }
 334
 335 /*
 336  * Call function on an online CPU.
 337  */
 338 void smp_call_online_cpu(void (*func)(void *), void *data)
 339 {
 340         struct pcpu *pcpu;
 341
 342         /* Use the current cpu if it is online. */
 343         pcpu = pcpu_find_address(cpu_online_mask, stap());
 344         if (!pcpu)
 345                 /* Use the first online cpu. */
 346                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 347         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 348 }
 349
 350 /*
 351  * Call function on the ipl CPU.
 352  */
 353 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 354 {
 355         pcpu_delegate(&pcpu_devices[0], func, data,
 356                       pcpu_devices->lowcore->panic_stack -
 357                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 358 }
 359
 360 int smp_find_processor_id(u16 address)
 361 {
 362         int cpu;
 363
 364         for_each_present_cpu(cpu)
 365                 if (pcpu_devices[cpu].address == address)
 366                         return cpu;
 367         return -1;
 368 }
 369
 370 bool arch_vcpu_is_preempted(int cpu)
 371 {
 372         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 373                 return false;
 374         if (pcpu_running(pcpu_devices + cpu))
 375                 return false;
 376         return true;
 377 }
 378 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 379
 380 void smp_yield_cpu(int cpu)
 381 {
 382         if (MACHINE_HAS_DIAG9C) {
 383                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 384                 asm volatile("diag %0,0,0x9c"
 385                              : : "d" (pcpu_devices[cpu].address));
 386         } else if (MACHINE_HAS_DIAG44) {
 387                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 388                 asm volatile("diag 0,0,0x44");
 389         }
 390 }
 391
 392 /*
 393  * Send cpus emergency shutdown signal. This gives the cpus the
 394  * opportunity to complete outstanding interrupts.
 395  */
 396 static void smp_emergency_stop(cpumask_t *cpumask)
 397 {
 398         u64 end;
 399         int cpu;
 400
 401         end = get_tod_clock() + (1000000UL << 12);
 402         for_each_cpu(cpu, cpumask) {
 403                 struct pcpu *pcpu = pcpu_devices + cpu;
 404                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 405                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 406                                    0, NULL) == SIGP_CC_BUSY &&
 407                        get_tod_clock() < end)
 408                         cpu_relax();
 409         }
 410         while (get_tod_clock() < end) {
 411                 for_each_cpu(cpu, cpumask)
 412                         if (pcpu_stopped(pcpu_devices + cpu))
 413                                 cpumask_clear_cpu(cpu, cpumask);
 414                 if (cpumask_empty(cpumask))
 415                         break;
 416                 cpu_relax();
 417         }
 418 }
 419
 420 /*
 421  * Stop all cpus but the current one.
 422  */
 423 void smp_send_stop(void)
 424 {
 425         cpumask_t cpumask;
 426         int cpu;
 427
 428         /* Disable all interrupts/machine checks */
 429         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 430         trace_hardirqs_off();
 431
 432         debug_set_critical();
 433         cpumask_copy(&cpumask, cpu_online_mask);
 434         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 435
 436         if (oops_in_progress)
 437                 smp_emergency_stop(&cpumask);
 438
 439         /* stop all processors */
 440         for_each_cpu(cpu, &cpumask) {
 441                 struct pcpu *pcpu = pcpu_devices + cpu;
 442                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 443                 while (!pcpu_stopped(pcpu))
 444                         cpu_relax();
 445         }
 446 }
 447
 448 /*
 449  * This is the main routine where commands issued by other
 450  * cpus are handled.
 451  */
 452 static void smp_handle_ext_call(void)
 453 {
 454         unsigned long bits;
 455
 456         /* handle bit signal external calls */
 457         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 458         if (test_bit(ec_stop_cpu, &bits))
 459                 smp_stop_cpu();
 460         if (test_bit(ec_schedule, &bits))
 461                 scheduler_ipi();
 462         if (test_bit(ec_call_function_single, &bits))
 463                 generic_smp_call_function_single_interrupt();
 464 }
 465
 466 static void do_ext_call_interrupt(struct ext_code ext_code,
 467                                   unsigned int param32, unsigned long param64)
 468 {
 469         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 470         smp_handle_ext_call();
 471 }
 472
 473 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 474 {
 475         int cpu;
 476
 477         for_each_cpu(cpu, mask)
 478                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 479 }
 480
 481 void arch_send_call_function_single_ipi(int cpu)
 482 {
 483         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 484 }
 485
 486 /*
 487  * this function sends a 'reschedule' IPI to another CPU.
 488  * it goes straight through and wastes no time serializing
 489  * anything. Worst case is that we lose a reschedule ...
 490  */
 491 void smp_send_reschedule(int cpu)
 492 {
 493         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 494 }
 495
 496 /*
 497  * parameter area for the set/clear control bit callbacks
 498  */
 499 struct ec_creg_mask_parms {
 500         unsigned long orval;
 501         unsigned long andval;
 502         int cr;
 503 };
 504
 505 /*
 506  * callback for setting/clearing control bits
 507  */
 508 static void smp_ctl_bit_callback(void *info)
 509 {
 510         struct ec_creg_mask_parms *pp = info;
 511         unsigned long cregs[16];
 512
 513         __ctl_store(cregs, 0, 15);
 514         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 515         __ctl_load(cregs, 0, 15);
 516 }
 517
 518 /*
 519  * Set a bit in a control register of all cpus
 520  */
 521 void smp_ctl_set_bit(int cr, int bit)
 522 {
 523         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 524
 525         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 526 }
 527 EXPORT_SYMBOL(smp_ctl_set_bit);
 528
 529 /*
 530  * Clear a bit in a control register of all cpus
 531  */
 532 void smp_ctl_clear_bit(int cr, int bit)
 533 {
 534         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 535
 536         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 537 }
 538 EXPORT_SYMBOL(smp_ctl_clear_bit);
 539
 540 #ifdef CONFIG_CRASH_DUMP
 541
 542 int smp_store_status(int cpu)
 543 {
 544         struct pcpu *pcpu = pcpu_devices + cpu;
 545         unsigned long pa;
 546
 547         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 548         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 549                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 550                 return -EIO;
 551         if (!MACHINE_HAS_VX)
 552                 return 0;
 553         pa = __pa(pcpu->lowcore->vector_save_area_addr);
 554         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 555                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 556                 return -EIO;
 557         return 0;
 558 }
 559
 560 /*
 561  * Collect CPU state of the previous, crashed system.
 562  * There are four cases:
 563  * 1) standard zfcp dump
 564  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 565  *    The state for all CPUs except the boot CPU needs to be collected
 566  *    with sigp stop-and-store-status. The boot CPU state is located in
 567  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 568  *    will copy the boot CPU state from the HSA.
 569  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 570  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 571  *    The state for all CPUs except the boot CPU needs to be collected
 572  *    with sigp stop-and-store-status. The firmware or the boot-loader
 573  *    stored the registers of the boot CPU in the absolute lowcore in the
 574  *    memory of the old system.
 575  * 3) kdump and the old kernel did not store the CPU state,
 576  *    or stand-alone kdump for DASD
 577  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 578  *    The state for all CPUs except the boot CPU needs to be collected
 579  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 580  *    stored the registers of the boot CPU in the memory of the old system.
 581  * 4) kdump and the old kernel stored the CPU state
 582  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 583  *    This case does not exist for s390 anymore, setup_arch explicitly
 584  *    deactivates the elfcorehdr= kernel parameter
 585  */
 586 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 587                                      bool is_boot_cpu, unsigned long page)
 588 {
 589         __vector128 *vxrs = (__vector128 *) page;
 590
 591         if (is_boot_cpu)
 592                 vxrs = boot_cpu_vector_save_area;
 593         else
 594                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 595         save_area_add_vxrs(sa, vxrs);
 596 }
 597
 598 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 599                                      bool is_boot_cpu, unsigned long page)
 600 {
 601         void *regs = (void *) page;
 602
 603         if (is_boot_cpu)
 604                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 605         else
 606                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 607         save_area_add_regs(sa, regs);
 608 }
 609
 610 void __init smp_save_dump_cpus(void)
 611 {
 612         int addr, boot_cpu_addr, max_cpu_addr;
 613         struct save_area *sa;
 614         unsigned long page;
 615         bool is_boot_cpu;
 616
 617         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 618                 /* No previous system present, normal boot. */
 619                 return;
 620         /* Allocate a page as dumping area for the store status sigps */
 621         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 622         /* Set multi-threading state to the previous system. */
 623         pcpu_set_smt(sclp.mtid_prev);
 624         boot_cpu_addr = stap();
 625         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 626         for (addr = 0; addr <= max_cpu_addr; addr++) {
 627                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 628                     SIGP_CC_NOT_OPERATIONAL)
 629                         continue;
 630                 is_boot_cpu = (addr == boot_cpu_addr);
 631                 /* Allocate save area */
 632                 sa = save_area_alloc(is_boot_cpu);
 633                 if (!sa)
 634                         panic("could not allocate memory for save area\n");
 635                 if (MACHINE_HAS_VX)
 636                         /* Get the vector registers */
 637                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 638                 /*
 639                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 640                  * of the boot CPU are stored in the HSA. To retrieve
 641                  * these registers an SCLP request is required which is
 642                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 643                  */
 644                 if (!is_boot_cpu || OLDMEM_BASE)
 645                         /* Get the CPU registers */
 646                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 647         }
 648         memblock_free(page, PAGE_SIZE);
 649         diag308_reset();
 650         pcpu_set_smt(0);
 651 }
 652 #endif /* CONFIG_CRASH_DUMP */
 653
 654 void smp_cpu_set_polarization(int cpu, int val)
 655 {
 656         pcpu_devices[cpu].polarization = val;
 657 }
 658
 659 int smp_cpu_get_polarization(int cpu)
 660 {
 661         return pcpu_devices[cpu].polarization;
 662 }
 663
 664 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 665 {
 666         static int use_sigp_detection;
 667         int address;
 668
 669         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 670                 use_sigp_detection = 1;
 671                 for (address = 0;
 672                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 673                      address += (1U << smp_cpu_mt_shift)) {
 674                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 675                             SIGP_CC_NOT_OPERATIONAL)
 676                                 continue;
 677                         info->core[info->configured].core_id =
 678                                 address >> smp_cpu_mt_shift;
 679                         info->configured++;
 680                 }
 681                 info->combined = info->configured;
 682         }
 683 }
 684
 685 static int smp_add_present_cpu(int cpu);
 686
 687 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 688 {
 689         struct pcpu *pcpu;
 690         cpumask_t avail;
 691         int cpu, nr, i, j;
 692         u16 address;
 693
 694         nr = 0;
 695         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 696         cpu = cpumask_first(&avail);
 697         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 698                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 699                         continue;
 700                 address = info->core[i].core_id << smp_cpu_mt_shift;
 701                 for (j = 0; j <= smp_cpu_mtid; j++) {
 702                         if (pcpu_find_address(cpu_present_mask, address + j))
 703                                 continue;
 704                         pcpu = pcpu_devices + cpu;
 705                         pcpu->address = address + j;
 706                         pcpu->state =
 707                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 708                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 709                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 710                         set_cpu_present(cpu, true);
 711                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 712                                 set_cpu_present(cpu, false);
 713                         else
 714                                 nr++;
 715                         cpu = cpumask_next(cpu, &avail);
 716                         if (cpu >= nr_cpu_ids)
 717                                 break;
 718                 }
 719         }
 720         return nr;
 721 }
 722
 723 void __init smp_detect_cpus(void)
 724 {
 725         unsigned int cpu, mtid, c_cpus, s_cpus;
 726         struct sclp_core_info *info;
 727         u16 address;
 728
 729         /* Get CPU information */
 730         info = memblock_virt_alloc(sizeof(*info), 8);
 731         smp_get_core_info(info, 1);
 732         /* Find boot CPU type */
 733         if (sclp.has_core_type) {
 734                 address = stap();
 735                 for (cpu = 0; cpu < info->combined; cpu++)
 736                         if (info->core[cpu].core_id == address) {
 737                                 /* The boot cpu dictates the cpu type. */
 738                                 boot_core_type = info->core[cpu].type;
 739                                 break;
 740                         }
 741                 if (cpu >= info->combined)
 742                         panic("Could not find boot CPU type");
 743         }
 744
 745         /* Set multi-threading state for the current system */
 746         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 747         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 748         pcpu_set_smt(mtid);
 749
 750         /* Print number of CPUs */
 751         c_cpus = s_cpus = 0;
 752         for (cpu = 0; cpu < info->combined; cpu++) {
 753                 if (sclp.has_core_type &&
 754                     info->core[cpu].type != boot_core_type)
 755                         continue;
 756                 if (cpu < info->configured)
 757                         c_cpus += smp_cpu_mtid + 1;
 758                 else
 759                         s_cpus += smp_cpu_mtid + 1;
 760         }
 761         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 762
 763         /* Add CPUs present at boot */
 764         get_online_cpus();
 765         __smp_rescan_cpus(info, 0);
 766         put_online_cpus();
 767         memblock_free_early((unsigned long)info, sizeof(*info));
 768 }
 769
 770 /*
 771  *      Activate a secondary processor.
 772  */
 773 static void smp_start_secondary(void *cpuvoid)
 774 {
 775         S390_lowcore.last_update_clock = get_tod_clock();
 776         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 777         S390_lowcore.restart_fn = (unsigned long) do_restart;
 778         S390_lowcore.restart_data = 0;
 779         S390_lowcore.restart_source = -1UL;
 780         restore_access_regs(S390_lowcore.access_regs_save_area);
 781         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 782         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 783         cpu_init();
 784         preempt_disable();
 785         init_cpu_timer();
 786         vtime_init();
 787         pfault_init();
 788         notify_cpu_starting(smp_processor_id());
 789         set_cpu_online(smp_processor_id(), true);
 790         inc_irq_stat(CPU_RST);
 791         local_irq_enable();
 792         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 793 }
 794
 795 /* Upping and downing of CPUs */
 796 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 797 {
 798         struct pcpu *pcpu;
 799         int base, i, rc;
 800
 801         pcpu = pcpu_devices + cpu;
 802         if (pcpu->state != CPU_STATE_CONFIGURED)
 803                 return -EIO;
 804         base = smp_get_base_cpu(cpu);
 805         for (i = 0; i <= smp_cpu_mtid; i++) {
 806                 if (base + i < nr_cpu_ids)
 807                         if (cpu_online(base + i))
 808                                 break;
 809         }
 810         /*
 811          * If this is the first CPU of the core to get online
 812          * do an initial CPU reset.
 813          */
 814         if (i > smp_cpu_mtid &&
 815             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 816             SIGP_CC_ORDER_CODE_ACCEPTED)
 817                 return -EIO;
 818
 819         rc = pcpu_alloc_lowcore(pcpu, cpu);
 820         if (rc)
 821                 return rc;
 822         pcpu_prepare_secondary(pcpu, cpu);
 823         pcpu_attach_task(pcpu, tidle);
 824         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 825         /* Wait until cpu puts itself in the online & active maps */
 826         while (!cpu_online(cpu))
 827                 cpu_relax();
 828         return 0;
 829 }
 830
 831 static unsigned int setup_possible_cpus __initdata;
 832
 833 static int __init _setup_possible_cpus(char *s)
 834 {
 835         get_option(&s, &setup_possible_cpus);
 836         return 0;
 837 }
 838 early_param("possible_cpus", _setup_possible_cpus);
 839
 840 #ifdef CONFIG_HOTPLUG_CPU
 841
 842 int __cpu_disable(void)
 843 {
 844         unsigned long cregs[16];
 845
 846         /* Handle possible pending IPIs */
 847         smp_handle_ext_call();
 848         set_cpu_online(smp_processor_id(), false);
 849         /* Disable pseudo page faults on this cpu. */
 850         pfault_fini();
 851         /* Disable interrupt sources via control register. */
 852         __ctl_store(cregs, 0, 15);
 853         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 854         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 855         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 856         __ctl_load(cregs, 0, 15);
 857         clear_cpu_flag(CIF_NOHZ_DELAY);
 858         return 0;
 859 }
 860
 861 void __cpu_die(unsigned int cpu)
 862 {
 863         struct pcpu *pcpu;
 864
 865         /* Wait until target cpu is down */
 866         pcpu = pcpu_devices + cpu;
 867         while (!pcpu_stopped(pcpu))
 868                 cpu_relax();
 869         pcpu_free_lowcore(pcpu);
 870         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 871         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 872 }
 873
 874 void __noreturn cpu_die(void)
 875 {
 876         idle_task_exit();
 877         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 878         for (;;) ;
 879 }
 880
 881 #endif /* CONFIG_HOTPLUG_CPU */
 882
 883 void __init smp_fill_possible_mask(void)
 884 {
 885         unsigned int possible, sclp_max, cpu;
 886
 887         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 888         sclp_max = min(smp_max_threads, sclp_max);
 889         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 890         possible = setup_possible_cpus ?: nr_cpu_ids;
 891         possible = min(possible, sclp_max);
 892         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 893                 set_cpu_possible(cpu, true);
 894 }
 895
 896 void __init smp_prepare_cpus(unsigned int max_cpus)
 897 {
 898         /* request the 0x1201 emergency signal external interrupt */
 899         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 900                 panic("Couldn't request external interrupt 0x1201");
 901         /* request the 0x1202 external call external interrupt */
 902         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 903                 panic("Couldn't request external interrupt 0x1202");
 904 }
 905
 906 void __init smp_prepare_boot_cpu(void)
 907 {
 908         struct pcpu *pcpu = pcpu_devices;
 909
 910         pcpu->state = CPU_STATE_CONFIGURED;
 911         pcpu->address = stap();
 912         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 913         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 914         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 915         set_cpu_present(0, true);
 916         set_cpu_online(0, true);
 917 }
 918
 919 void __init smp_cpus_done(unsigned int max_cpus)
 920 {
 921 }
 922
 923 void __init smp_setup_processor_id(void)
 924 {
 925         S390_lowcore.cpu_nr = 0;
 926         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 927 }
 928
 929 /*
 930  * the frequency of the profiling timer can be changed
 931  * by writing a multiplier value into /proc/profile.
 932  *
 933  * usually you want to run this on all CPUs ;)
 934  */
 935 int setup_profiling_timer(unsigned int multiplier)
 936 {
 937         return 0;
 938 }
 939
 940 #ifdef CONFIG_HOTPLUG_CPU
 941 static ssize_t cpu_configure_show(struct device *dev,
 942                                   struct device_attribute *attr, char *buf)
 943 {
 944         ssize_t count;
 945
 946         mutex_lock(&smp_cpu_state_mutex);
 947         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 948         mutex_unlock(&smp_cpu_state_mutex);
 949         return count;
 950 }
 951
 952 static ssize_t cpu_configure_store(struct device *dev,
 953                                    struct device_attribute *attr,
 954                                    const char *buf, size_t count)
 955 {
 956         struct pcpu *pcpu;
 957         int cpu, val, rc, i;
 958         char delim;
 959
 960         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 961                 return -EINVAL;
 962         if (val != 0 && val != 1)
 963                 return -EINVAL;
 964         get_online_cpus();
 965         mutex_lock(&smp_cpu_state_mutex);
 966         rc = -EBUSY;
 967         /* disallow configuration changes of online cpus and cpu 0 */
 968         cpu = dev->id;
 969         cpu = smp_get_base_cpu(cpu);
 970         if (cpu == 0)
 971                 goto out;
 972         for (i = 0; i <= smp_cpu_mtid; i++)
 973                 if (cpu_online(cpu + i))
 974                         goto out;
 975         pcpu = pcpu_devices + cpu;
 976         rc = 0;
 977         switch (val) {
 978         case 0:
 979                 if (pcpu->state != CPU_STATE_CONFIGURED)
 980                         break;
 981                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
 982                 if (rc)
 983                         break;
 984                 for (i = 0; i <= smp_cpu_mtid; i++) {
 985                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
 986                                 continue;
 987                         pcpu[i].state = CPU_STATE_STANDBY;
 988                         smp_cpu_set_polarization(cpu + i,
 989                                                  POLARIZATION_UNKNOWN);
 990                 }
 991                 topology_expect_change();
 992                 break;
 993         case 1:
 994                 if (pcpu->state != CPU_STATE_STANDBY)
 995                         break;
 996                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
 997                 if (rc)
 998                         break;
 999                 for (i = 0; i <= smp_cpu_mtid; i++) {
1000                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1001                                 continue;
1002                         pcpu[i].state = CPU_STATE_CONFIGURED;
1003                         smp_cpu_set_polarization(cpu + i,
1004                                                  POLARIZATION_UNKNOWN);
1005                 }
1006                 topology_expect_change();
1007                 break;
1008         default:
1009                 break;
1010         }
1011 out:
1012         mutex_unlock(&smp_cpu_state_mutex);
1013         put_online_cpus();
1014         return rc ? rc : count;
1015 }
1016 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1017 #endif /* CONFIG_HOTPLUG_CPU */
1018
1019 static ssize_t show_cpu_address(struct device *dev,
1020                                 struct device_attribute *attr, char *buf)
1021 {
1022         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1023 }
1024 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1025
1026 static struct attribute *cpu_common_attrs[] = {
1027 #ifdef CONFIG_HOTPLUG_CPU
1028         &dev_attr_configure.attr,
1029 #endif
1030         &dev_attr_address.attr,
1031         NULL,
1032 };
1033
1034 static struct attribute_group cpu_common_attr_group = {
1035         .attrs = cpu_common_attrs,
1036 };
1037
1038 static struct attribute *cpu_online_attrs[] = {
1039         &dev_attr_idle_count.attr,
1040         &dev_attr_idle_time_us.attr,
1041         NULL,
1042 };
1043
1044 static struct attribute_group cpu_online_attr_group = {
1045         .attrs = cpu_online_attrs,
1046 };
1047
1048 static int smp_cpu_online(unsigned int cpu)
1049 {
1050         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1051
1052         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1053 }
1054 static int smp_cpu_pre_down(unsigned int cpu)
1055 {
1056         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1057
1058         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1059         return 0;
1060 }
1061
1062 static int smp_add_present_cpu(int cpu)
1063 {
1064         struct device *s;
1065         struct cpu *c;
1066         int rc;
1067
1068         c = kzalloc(sizeof(*c), GFP_KERNEL);
1069         if (!c)
1070                 return -ENOMEM;
1071         per_cpu(cpu_device, cpu) = c;
1072         s = &c->dev;
1073         c->hotpluggable = 1;
1074         rc = register_cpu(c, cpu);
1075         if (rc)
1076                 goto out;
1077         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1078         if (rc)
1079                 goto out_cpu;
1080         rc = topology_cpu_init(c);
1081         if (rc)
1082                 goto out_topology;
1083         return 0;
1084
1085 out_topology:
1086         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1087 out_cpu:
1088 #ifdef CONFIG_HOTPLUG_CPU
1089         unregister_cpu(c);
1090 #endif
1091 out:
1092         return rc;
1093 }
1094
1095 #ifdef CONFIG_HOTPLUG_CPU
1096
1097 int __ref smp_rescan_cpus(void)
1098 {
1099         struct sclp_core_info *info;
1100         int nr;
1101
1102         info = kzalloc(sizeof(*info), GFP_KERNEL);
1103         if (!info)
1104                 return -ENOMEM;
1105         smp_get_core_info(info, 0);
1106         get_online_cpus();
1107         mutex_lock(&smp_cpu_state_mutex);
1108         nr = __smp_rescan_cpus(info, 1);
1109         mutex_unlock(&smp_cpu_state_mutex);
1110         put_online_cpus();
1111         kfree(info);
1112         if (nr)
1113                 topology_schedule_update();
1114         return 0;
1115 }
1116
1117 static ssize_t __ref rescan_store(struct device *dev,
1118                                   struct device_attribute *attr,
1119                                   const char *buf,
1120                                   size_t count)
1121 {
1122         int rc;
1123
1124         rc = smp_rescan_cpus();
1125         return rc ? rc : count;
1126 }
1127 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1128 #endif /* CONFIG_HOTPLUG_CPU */
1129
1130 static int __init s390_smp_init(void)
1131 {
1132         int cpu, rc = 0;
1133
1134 #ifdef CONFIG_HOTPLUG_CPU
1135         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1136         if (rc)
1137                 return rc;
1138 #endif
1139         for_each_present_cpu(cpu) {
1140                 rc = smp_add_present_cpu(cpu);
1141                 if (rc)
1142                         goto out;
1143         }
1144
1145         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1146                                smp_cpu_online, smp_cpu_pre_down);
1147 out:
1148         return rc;
1149 }
1150 subsys_initcall(s390_smp_init);