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 <linux/memblock.h>
  35 #include <asm/asm-offsets.h>
  36 #include <asm/diag.h>
  37 #include <asm/switch_to.h>
  38 #include <asm/facility.h>
  39 #include <asm/ipl.h>
  40 #include <asm/setup.h>
  41 #include <asm/irq.h>
  42 #include <asm/tlbflush.h>
  43 #include <asm/vtimer.h>
  44 #include <asm/lowcore.h>
  45 #include <asm/sclp.h>
  46 #include <asm/vdso.h>
  47 #include <asm/debug.h>
  48 #include <asm/os_info.h>
  49 #include <asm/sigp.h>
  50 #include <asm/idle.h>
  51 #include "entry.h"
  52
  53 enum {
  54         ec_schedule = 0,
  55         ec_call_function_single,
  56         ec_stop_cpu,
  57 };
  58
  59 enum {
  60         CPU_STATE_STANDBY,
  61         CPU_STATE_CONFIGURED,
  62 };
  63
  64 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  65
  66 struct pcpu {
  67         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  68         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  69         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  70         signed char state;              /* physical cpu state */
  71         signed char polarization;       /* physical polarization */
  72         u16 address;                    /* physical cpu address */
  73 };
  74
  75 static u8 boot_core_type;
  76 static struct pcpu pcpu_devices[NR_CPUS];
  77
  78 unsigned int smp_cpu_mt_shift;
  79 EXPORT_SYMBOL(smp_cpu_mt_shift);
  80
  81 unsigned int smp_cpu_mtid;
  82 EXPORT_SYMBOL(smp_cpu_mtid);
  83
  84 #ifdef CONFIG_CRASH_DUMP
  85 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  86 #endif
  87
  88 static unsigned int smp_max_threads __initdata = -1U;
  89
  90 static int __init early_nosmt(char *s)
  91 {
  92         smp_max_threads = 1;
  93         return 0;
  94 }
  95 early_param("nosmt", early_nosmt);
  96
  97 static int __init early_smt(char *s)
  98 {
  99         get_option(&s, &smp_max_threads);
 100         return 0;
 101 }
 102 early_param("smt", early_smt);
 103
 104 /*
 105  * The smp_cpu_state_mutex must be held when changing the state or polarization
 106  * member of a pcpu data structure within the pcpu_devices arreay.
 107  */
 108 DEFINE_MUTEX(smp_cpu_state_mutex);
 109
 110 /*
 111  * Signal processor helper functions.
 112  */
 113 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 114 {
 115         int cc;
 116
 117         while (1) {
 118                 cc = __pcpu_sigp(addr, order, parm, NULL);
 119                 if (cc != SIGP_CC_BUSY)
 120                         return cc;
 121                 cpu_relax();
 122         }
 123 }
 124
 125 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 126 {
 127         int cc, retry;
 128
 129         for (retry = 0; ; retry++) {
 130                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 131                 if (cc != SIGP_CC_BUSY)
 132                         break;
 133                 if (retry >= 3)
 134                         udelay(10);
 135         }
 136         return cc;
 137 }
 138
 139 static inline int pcpu_stopped(struct pcpu *pcpu)
 140 {
 141         u32 uninitialized_var(status);
 142
 143         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 144                         0, &status) != SIGP_CC_STATUS_STORED)
 145                 return 0;
 146         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 147 }
 148
 149 static inline int pcpu_running(struct pcpu *pcpu)
 150 {
 151         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 152                         0, NULL) != SIGP_CC_STATUS_STORED)
 153                 return 1;
 154         /* Status stored condition code is equivalent to cpu not running. */
 155         return 0;
 156 }
 157
 158 /*
 159  * Find struct pcpu by cpu address.
 160  */
 161 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 162 {
 163         int cpu;
 164
 165         for_each_cpu(cpu, mask)
 166                 if (pcpu_devices[cpu].address == address)
 167                         return pcpu_devices + cpu;
 168         return NULL;
 169 }
 170
 171 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 172 {
 173         int order;
 174
 175         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 176                 return;
 177         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 178         pcpu->ec_clk = get_tod_clock_fast();
 179         pcpu_sigp_retry(pcpu, order, 0);
 180 }
 181
 182 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 183 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 184
 185 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 186 {
 187         unsigned long async_stack, panic_stack;
 188         struct lowcore *lc;
 189
 190         if (pcpu != &pcpu_devices[0]) {
 191                 pcpu->lowcore = (struct lowcore *)
 192                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 193                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 194                 panic_stack = __get_free_page(GFP_KERNEL);
 195                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 196                         goto out;
 197         } else {
 198                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 199                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 200         }
 201         lc = pcpu->lowcore;
 202         memcpy(lc, &S390_lowcore, 512);
 203         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 204         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 205         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 206         lc->cpu_nr = cpu;
 207         lc->spinlock_lockval = arch_spin_lockval(cpu);
 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         lowcore_ptr[cpu] = lc;
 214         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 215         return 0;
 216 out:
 217         if (pcpu != &pcpu_devices[0]) {
 218                 free_page(panic_stack);
 219                 free_pages(async_stack, ASYNC_ORDER);
 220                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 221         }
 222         return -ENOMEM;
 223 }
 224
 225 #ifdef CONFIG_HOTPLUG_CPU
 226
 227 static void pcpu_free_lowcore(struct pcpu *pcpu)
 228 {
 229         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 230         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 231         vdso_free_per_cpu(pcpu->lowcore);
 232         if (pcpu == &pcpu_devices[0])
 233                 return;
 234         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 235         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 236         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 237 }
 238
 239 #endif /* CONFIG_HOTPLUG_CPU */
 240
 241 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 242 {
 243         struct lowcore *lc = pcpu->lowcore;
 244
 245         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 246         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 247         lc->cpu_nr = cpu;
 248         lc->spinlock_lockval = arch_spin_lockval(cpu);
 249         lc->percpu_offset = __per_cpu_offset[cpu];
 250         lc->kernel_asce = S390_lowcore.kernel_asce;
 251         lc->machine_flags = S390_lowcore.machine_flags;
 252         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 253         __ctl_store(lc->cregs_save_area, 0, 15);
 254         save_access_regs((unsigned int *) lc->access_regs_save_area);
 255         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 256                MAX_FACILITY_BIT/8);
 257 }
 258
 259 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 260 {
 261         struct lowcore *lc = pcpu->lowcore;
 262         struct thread_info *ti = task_thread_info(tsk);
 263
 264         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 265                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 266         lc->thread_info = (unsigned long) task_thread_info(tsk);
 267         lc->current_task = (unsigned long) tsk;
 268         lc->lpp = LPP_MAGIC;
 269         lc->current_pid = tsk->pid;
 270         lc->user_timer = ti->user_timer;
 271         lc->system_timer = ti->system_timer;
 272         lc->steal_timer = 0;
 273 }
 274
 275 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 276 {
 277         struct lowcore *lc = pcpu->lowcore;
 278
 279         lc->restart_stack = lc->kernel_stack;
 280         lc->restart_fn = (unsigned long) func;
 281         lc->restart_data = (unsigned long) data;
 282         lc->restart_source = -1UL;
 283         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 284 }
 285
 286 /*
 287  * Call function via PSW restart on pcpu and stop the current cpu.
 288  */
 289 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 290                           void *data, unsigned long stack)
 291 {
 292         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 293         unsigned long source_cpu = stap();
 294
 295         __load_psw_mask(PSW_KERNEL_BITS);
 296         if (pcpu->address == source_cpu)
 297                 func(data);     /* should not return */
 298         /* Stop target cpu (if func returns this stops the current cpu). */
 299         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 300         /* Restart func on the target cpu and stop the current cpu. */
 301         mem_assign_absolute(lc->restart_stack, stack);
 302         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 303         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 304         mem_assign_absolute(lc->restart_source, source_cpu);
 305         asm volatile(
 306                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 307                 "       brc     2,0b    # busy, try again\n"
 308                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 309                 "       brc     2,1b    # busy, try again\n"
 310                 : : "d" (pcpu->address), "d" (source_cpu),
 311                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 312                 : "0", "1", "cc");
 313         for (;;) ;
 314 }
 315
 316 /*
 317  * Enable additional logical cpus for multi-threading.
 318  */
 319 static int pcpu_set_smt(unsigned int mtid)
 320 {
 321         int cc;
 322
 323         if (smp_cpu_mtid == mtid)
 324                 return 0;
 325         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 326         if (cc == 0) {
 327                 smp_cpu_mtid = mtid;
 328                 smp_cpu_mt_shift = 0;
 329                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 330                         smp_cpu_mt_shift++;
 331                 pcpu_devices[0].address = stap();
 332         }
 333         return cc;
 334 }
 335
 336 /*
 337  * Call function on an online CPU.
 338  */
 339 void smp_call_online_cpu(void (*func)(void *), void *data)
 340 {
 341         struct pcpu *pcpu;
 342
 343         /* Use the current cpu if it is online. */
 344         pcpu = pcpu_find_address(cpu_online_mask, stap());
 345         if (!pcpu)
 346                 /* Use the first online cpu. */
 347                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 348         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 349 }
 350
 351 /*
 352  * Call function on the ipl CPU.
 353  */
 354 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 355 {
 356         pcpu_delegate(&pcpu_devices[0], func, data,
 357                       pcpu_devices->lowcore->panic_stack -
 358                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 359 }
 360
 361 int smp_find_processor_id(u16 address)
 362 {
 363         int cpu;
 364
 365         for_each_present_cpu(cpu)
 366                 if (pcpu_devices[cpu].address == address)
 367                         return cpu;
 368         return -1;
 369 }
 370
 371 int smp_vcpu_scheduled(int cpu)
 372 {
 373         return pcpu_running(pcpu_devices + cpu);
 374 }
 375
 376 void smp_yield_cpu(int cpu)
 377 {
 378         if (MACHINE_HAS_DIAG9C) {
 379                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 380                 asm volatile("diag %0,0,0x9c"
 381                              : : "d" (pcpu_devices[cpu].address));
 382         } else if (MACHINE_HAS_DIAG44) {
 383                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 384                 asm volatile("diag 0,0,0x44");
 385         }
 386 }
 387
 388 /*
 389  * Send cpus emergency shutdown signal. This gives the cpus the
 390  * opportunity to complete outstanding interrupts.
 391  */
 392 static void smp_emergency_stop(cpumask_t *cpumask)
 393 {
 394         u64 end;
 395         int cpu;
 396
 397         end = get_tod_clock() + (1000000UL << 12);
 398         for_each_cpu(cpu, cpumask) {
 399                 struct pcpu *pcpu = pcpu_devices + cpu;
 400                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 401                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 402                                    0, NULL) == SIGP_CC_BUSY &&
 403                        get_tod_clock() < end)
 404                         cpu_relax();
 405         }
 406         while (get_tod_clock() < end) {
 407                 for_each_cpu(cpu, cpumask)
 408                         if (pcpu_stopped(pcpu_devices + cpu))
 409                                 cpumask_clear_cpu(cpu, cpumask);
 410                 if (cpumask_empty(cpumask))
 411                         break;
 412                 cpu_relax();
 413         }
 414 }
 415
 416 /*
 417  * Stop all cpus but the current one.
 418  */
 419 void smp_send_stop(void)
 420 {
 421         cpumask_t cpumask;
 422         int cpu;
 423
 424         /* Disable all interrupts/machine checks */
 425         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 426         trace_hardirqs_off();
 427
 428         debug_set_critical();
 429         cpumask_copy(&cpumask, cpu_online_mask);
 430         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 431
 432         if (oops_in_progress)
 433                 smp_emergency_stop(&cpumask);
 434
 435         /* stop all processors */
 436         for_each_cpu(cpu, &cpumask) {
 437                 struct pcpu *pcpu = pcpu_devices + cpu;
 438                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 439                 while (!pcpu_stopped(pcpu))
 440                         cpu_relax();
 441         }
 442 }
 443
 444 /*
 445  * This is the main routine where commands issued by other
 446  * cpus are handled.
 447  */
 448 static void smp_handle_ext_call(void)
 449 {
 450         unsigned long bits;
 451
 452         /* handle bit signal external calls */
 453         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 454         if (test_bit(ec_stop_cpu, &bits))
 455                 smp_stop_cpu();
 456         if (test_bit(ec_schedule, &bits))
 457                 scheduler_ipi();
 458         if (test_bit(ec_call_function_single, &bits))
 459                 generic_smp_call_function_single_interrupt();
 460 }
 461
 462 static void do_ext_call_interrupt(struct ext_code ext_code,
 463                                   unsigned int param32, unsigned long param64)
 464 {
 465         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 466         smp_handle_ext_call();
 467 }
 468
 469 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 470 {
 471         int cpu;
 472
 473         for_each_cpu(cpu, mask)
 474                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 475 }
 476
 477 void arch_send_call_function_single_ipi(int cpu)
 478 {
 479         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 480 }
 481
 482 /*
 483  * this function sends a 'reschedule' IPI to another CPU.
 484  * it goes straight through and wastes no time serializing
 485  * anything. Worst case is that we lose a reschedule ...
 486  */
 487 void smp_send_reschedule(int cpu)
 488 {
 489         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 490 }
 491
 492 /*
 493  * parameter area for the set/clear control bit callbacks
 494  */
 495 struct ec_creg_mask_parms {
 496         unsigned long orval;
 497         unsigned long andval;
 498         int cr;
 499 };
 500
 501 /*
 502  * callback for setting/clearing control bits
 503  */
 504 static void smp_ctl_bit_callback(void *info)
 505 {
 506         struct ec_creg_mask_parms *pp = info;
 507         unsigned long cregs[16];
 508
 509         __ctl_store(cregs, 0, 15);
 510         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 511         __ctl_load(cregs, 0, 15);
 512 }
 513
 514 /*
 515  * Set a bit in a control register of all cpus
 516  */
 517 void smp_ctl_set_bit(int cr, int bit)
 518 {
 519         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 520
 521         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 522 }
 523 EXPORT_SYMBOL(smp_ctl_set_bit);
 524
 525 /*
 526  * Clear a bit in a control register of all cpus
 527  */
 528 void smp_ctl_clear_bit(int cr, int bit)
 529 {
 530         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 531
 532         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 533 }
 534 EXPORT_SYMBOL(smp_ctl_clear_bit);
 535
 536 #ifdef CONFIG_CRASH_DUMP
 537
 538 int smp_store_status(int cpu)
 539 {
 540         struct pcpu *pcpu = pcpu_devices + cpu;
 541         unsigned long pa;
 542
 543         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 544         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 545                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 546                 return -EIO;
 547         if (!MACHINE_HAS_VX)
 548                 return 0;
 549         pa = __pa(pcpu->lowcore->vector_save_area_addr);
 550         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 551                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 552                 return -EIO;
 553         return 0;
 554 }
 555
 556 /*
 557  * Collect CPU state of the previous, crashed system.
 558  * There are four cases:
 559  * 1) standard zfcp dump
 560  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 561  *    The state for all CPUs except the boot CPU needs to be collected
 562  *    with sigp stop-and-store-status. The boot CPU state is located in
 563  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 564  *    will copy the boot CPU state from the HSA.
 565  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 566  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 567  *    The state for all CPUs except the boot CPU needs to be collected
 568  *    with sigp stop-and-store-status. The firmware or the boot-loader
 569  *    stored the registers of the boot CPU in the absolute lowcore in the
 570  *    memory of the old system.
 571  * 3) kdump and the old kernel did not store the CPU state,
 572  *    or stand-alone kdump for DASD
 573  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 574  *    The state for all CPUs except the boot CPU needs to be collected
 575  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 576  *    stored the registers of the boot CPU in the memory of the old system.
 577  * 4) kdump and the old kernel stored the CPU state
 578  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 579  *    This case does not exist for s390 anymore, setup_arch explicitly
 580  *    deactivates the elfcorehdr= kernel parameter
 581  */
 582 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 583                                      bool is_boot_cpu, unsigned long page)
 584 {
 585         __vector128 *vxrs = (__vector128 *) page;
 586
 587         if (is_boot_cpu)
 588                 vxrs = boot_cpu_vector_save_area;
 589         else
 590                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 591         save_area_add_vxrs(sa, vxrs);
 592 }
 593
 594 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 595                                      bool is_boot_cpu, unsigned long page)
 596 {
 597         void *regs = (void *) page;
 598
 599         if (is_boot_cpu)
 600                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 601         else
 602                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 603         save_area_add_regs(sa, regs);
 604 }
 605
 606 void __init smp_save_dump_cpus(void)
 607 {
 608         int addr, boot_cpu_addr, max_cpu_addr;
 609         struct save_area *sa;
 610         unsigned long page;
 611         bool is_boot_cpu;
 612
 613         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 614                 /* No previous system present, normal boot. */
 615                 return;
 616         /* Allocate a page as dumping area for the store status sigps */
 617         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 618         /* Set multi-threading state to the previous system. */
 619         pcpu_set_smt(sclp.mtid_prev);
 620         boot_cpu_addr = stap();
 621         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 622         for (addr = 0; addr <= max_cpu_addr; addr++) {
 623                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 624                     SIGP_CC_NOT_OPERATIONAL)
 625                         continue;
 626                 is_boot_cpu = (addr == boot_cpu_addr);
 627                 /* Allocate save area */
 628                 sa = save_area_alloc(is_boot_cpu);
 629                 if (!sa)
 630                         panic("could not allocate memory for save area\n");
 631                 if (MACHINE_HAS_VX)
 632                         /* Get the vector registers */
 633                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 634                 /*
 635                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 636                  * of the boot CPU are stored in the HSA. To retrieve
 637                  * these registers an SCLP request is required which is
 638                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 639                  */
 640                 if (!is_boot_cpu || OLDMEM_BASE)
 641                         /* Get the CPU registers */
 642                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 643         }
 644         memblock_free(page, PAGE_SIZE);
 645         diag308_reset();
 646         pcpu_set_smt(0);
 647 }
 648 #endif /* CONFIG_CRASH_DUMP */
 649
 650 void smp_cpu_set_polarization(int cpu, int val)
 651 {
 652         pcpu_devices[cpu].polarization = val;
 653 }
 654
 655 int smp_cpu_get_polarization(int cpu)
 656 {
 657         return pcpu_devices[cpu].polarization;
 658 }
 659
 660 static struct sclp_core_info *smp_get_core_info(void)
 661 {
 662         static int use_sigp_detection;
 663         struct sclp_core_info *info;
 664         int address;
 665
 666         info = kzalloc(sizeof(*info), GFP_KERNEL);
 667         if (info && (use_sigp_detection || sclp_get_core_info(info))) {
 668                 use_sigp_detection = 1;
 669                 for (address = 0;
 670                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 671                      address += (1U << smp_cpu_mt_shift)) {
 672                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 673                             SIGP_CC_NOT_OPERATIONAL)
 674                                 continue;
 675                         info->core[info->configured].core_id =
 676                                 address >> smp_cpu_mt_shift;
 677                         info->configured++;
 678                 }
 679                 info->combined = info->configured;
 680         }
 681         return info;
 682 }
 683
 684 static int smp_add_present_cpu(int cpu);
 685
 686 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 687 {
 688         struct pcpu *pcpu;
 689         cpumask_t avail;
 690         int cpu, nr, i, j;
 691         u16 address;
 692
 693         nr = 0;
 694         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 695         cpu = cpumask_first(&avail);
 696         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 697                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 698                         continue;
 699                 address = info->core[i].core_id << smp_cpu_mt_shift;
 700                 for (j = 0; j <= smp_cpu_mtid; j++) {
 701                         if (pcpu_find_address(cpu_present_mask, address + j))
 702                                 continue;
 703                         pcpu = pcpu_devices + cpu;
 704                         pcpu->address = address + j;
 705                         pcpu->state =
 706                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 707                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 708                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 709                         set_cpu_present(cpu, true);
 710                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 711                                 set_cpu_present(cpu, false);
 712                         else
 713                                 nr++;
 714                         cpu = cpumask_next(cpu, &avail);
 715                         if (cpu >= nr_cpu_ids)
 716                                 break;
 717                 }
 718         }
 719         return nr;
 720 }
 721
 722 static void __init smp_detect_cpus(void)
 723 {
 724         unsigned int cpu, mtid, c_cpus, s_cpus;
 725         struct sclp_core_info *info;
 726         u16 address;
 727
 728         /* Get CPU information */
 729         info = smp_get_core_info();
 730         if (!info)
 731                 panic("smp_detect_cpus failed to allocate memory\n");
 732
 733         /* Find boot CPU type */
 734         if (sclp.has_core_type) {
 735                 address = stap();
 736                 for (cpu = 0; cpu < info->combined; cpu++)
 737                         if (info->core[cpu].core_id == address) {
 738                                 /* The boot cpu dictates the cpu type. */
 739                                 boot_core_type = info->core[cpu].type;
 740                                 break;
 741                         }
 742                 if (cpu >= info->combined)
 743                         panic("Could not find boot CPU type");
 744         }
 745
 746         /* Set multi-threading state for the current system */
 747         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 748         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 749         pcpu_set_smt(mtid);
 750
 751         /* Print number of CPUs */
 752         c_cpus = s_cpus = 0;
 753         for (cpu = 0; cpu < info->combined; cpu++) {
 754                 if (sclp.has_core_type &&
 755                     info->core[cpu].type != boot_core_type)
 756                         continue;
 757                 if (cpu < info->configured)
 758                         c_cpus += smp_cpu_mtid + 1;
 759                 else
 760                         s_cpus += smp_cpu_mtid + 1;
 761         }
 762         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 763
 764         /* Add CPUs present at boot */
 765         get_online_cpus();
 766         __smp_rescan_cpus(info, 0);
 767         put_online_cpus();
 768         kfree(info);
 769 }
 770
 771 /*
 772  *      Activate a secondary processor.
 773  */
 774 static void smp_start_secondary(void *cpuvoid)
 775 {
 776         S390_lowcore.last_update_clock = get_tod_clock();
 777         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 778         S390_lowcore.restart_fn = (unsigned long) do_restart;
 779         S390_lowcore.restart_data = 0;
 780         S390_lowcore.restart_source = -1UL;
 781         restore_access_regs(S390_lowcore.access_regs_save_area);
 782         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 783         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 784         cpu_init();
 785         preempt_disable();
 786         init_cpu_timer();
 787         vtime_init();
 788         pfault_init();
 789         notify_cpu_starting(smp_processor_id());
 790         set_cpu_online(smp_processor_id(), true);
 791         inc_irq_stat(CPU_RST);
 792         local_irq_enable();
 793         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 794 }
 795
 796 /* Upping and downing of CPUs */
 797 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 798 {
 799         struct pcpu *pcpu;
 800         int base, i, rc;
 801
 802         pcpu = pcpu_devices + cpu;
 803         if (pcpu->state != CPU_STATE_CONFIGURED)
 804                 return -EIO;
 805         base = cpu - (cpu % (smp_cpu_mtid + 1));
 806         for (i = 0; i <= smp_cpu_mtid; i++) {
 807                 if (base + i < nr_cpu_ids)
 808                         if (cpu_online(base + i))
 809                                 break;
 810         }
 811         /*
 812          * If this is the first CPU of the core to get online
 813          * do an initial CPU reset.
 814          */
 815         if (i > smp_cpu_mtid &&
 816             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 817             SIGP_CC_ORDER_CODE_ACCEPTED)
 818                 return -EIO;
 819
 820         rc = pcpu_alloc_lowcore(pcpu, cpu);
 821         if (rc)
 822                 return rc;
 823         pcpu_prepare_secondary(pcpu, cpu);
 824         pcpu_attach_task(pcpu, tidle);
 825         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 826         /* Wait until cpu puts itself in the online & active maps */
 827         while (!cpu_online(cpu))
 828                 cpu_relax();
 829         return 0;
 830 }
 831
 832 static unsigned int setup_possible_cpus __initdata;
 833
 834 static int __init _setup_possible_cpus(char *s)
 835 {
 836         get_option(&s, &setup_possible_cpus);
 837         return 0;
 838 }
 839 early_param("possible_cpus", _setup_possible_cpus);
 840
 841 #ifdef CONFIG_HOTPLUG_CPU
 842
 843 int __cpu_disable(void)
 844 {
 845         unsigned long cregs[16];
 846
 847         /* Handle possible pending IPIs */
 848         smp_handle_ext_call();
 849         set_cpu_online(smp_processor_id(), false);
 850         /* Disable pseudo page faults on this cpu. */
 851         pfault_fini();
 852         /* Disable interrupt sources via control register. */
 853         __ctl_store(cregs, 0, 15);
 854         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 855         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 856         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 857         __ctl_load(cregs, 0, 15);
 858         clear_cpu_flag(CIF_NOHZ_DELAY);
 859         return 0;
 860 }
 861
 862 void __cpu_die(unsigned int cpu)
 863 {
 864         struct pcpu *pcpu;
 865
 866         /* Wait until target cpu is down */
 867         pcpu = pcpu_devices + cpu;
 868         while (!pcpu_stopped(pcpu))
 869                 cpu_relax();
 870         pcpu_free_lowcore(pcpu);
 871         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 872         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 873 }
 874
 875 void __noreturn cpu_die(void)
 876 {
 877         idle_task_exit();
 878         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 879         for (;;) ;
 880 }
 881
 882 #endif /* CONFIG_HOTPLUG_CPU */
 883
 884 void __init smp_fill_possible_mask(void)
 885 {
 886         unsigned int possible, sclp_max, cpu;
 887
 888         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 889         sclp_max = min(smp_max_threads, sclp_max);
 890         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 891         possible = setup_possible_cpus ?: nr_cpu_ids;
 892         possible = min(possible, sclp_max);
 893         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 894                 set_cpu_possible(cpu, true);
 895 }
 896
 897 void __init smp_prepare_cpus(unsigned int max_cpus)
 898 {
 899         /* request the 0x1201 emergency signal external interrupt */
 900         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 901                 panic("Couldn't request external interrupt 0x1201");
 902         /* request the 0x1202 external call external interrupt */
 903         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 904                 panic("Couldn't request external interrupt 0x1202");
 905         smp_detect_cpus();
 906 }
 907
 908 void __init smp_prepare_boot_cpu(void)
 909 {
 910         struct pcpu *pcpu = pcpu_devices;
 911
 912         pcpu->state = CPU_STATE_CONFIGURED;
 913         pcpu->address = stap();
 914         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 915         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 916         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 917         set_cpu_present(0, true);
 918         set_cpu_online(0, true);
 919 }
 920
 921 void __init smp_cpus_done(unsigned int max_cpus)
 922 {
 923 }
 924
 925 void __init smp_setup_processor_id(void)
 926 {
 927         S390_lowcore.cpu_nr = 0;
 928         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 929 }
 930
 931 /*
 932  * the frequency of the profiling timer can be changed
 933  * by writing a multiplier value into /proc/profile.
 934  *
 935  * usually you want to run this on all CPUs ;)
 936  */
 937 int setup_profiling_timer(unsigned int multiplier)
 938 {
 939         return 0;
 940 }
 941
 942 #ifdef CONFIG_HOTPLUG_CPU
 943 static ssize_t cpu_configure_show(struct device *dev,
 944                                   struct device_attribute *attr, char *buf)
 945 {
 946         ssize_t count;
 947
 948         mutex_lock(&smp_cpu_state_mutex);
 949         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 950         mutex_unlock(&smp_cpu_state_mutex);
 951         return count;
 952 }
 953
 954 static ssize_t cpu_configure_store(struct device *dev,
 955                                    struct device_attribute *attr,
 956                                    const char *buf, size_t count)
 957 {
 958         struct pcpu *pcpu;
 959         int cpu, val, rc, i;
 960         char delim;
 961
 962         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 963                 return -EINVAL;
 964         if (val != 0 && val != 1)
 965                 return -EINVAL;
 966         get_online_cpus();
 967         mutex_lock(&smp_cpu_state_mutex);
 968         rc = -EBUSY;
 969         /* disallow configuration changes of online cpus and cpu 0 */
 970         cpu = dev->id;
 971         cpu -= cpu % (smp_cpu_mtid + 1);
 972         if (cpu == 0)
 973                 goto out;
 974         for (i = 0; i <= smp_cpu_mtid; i++)
 975                 if (cpu_online(cpu + i))
 976                         goto out;
 977         pcpu = pcpu_devices + cpu;
 978         rc = 0;
 979         switch (val) {
 980         case 0:
 981                 if (pcpu->state != CPU_STATE_CONFIGURED)
 982                         break;
 983                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
 984                 if (rc)
 985                         break;
 986                 for (i = 0; i <= smp_cpu_mtid; i++) {
 987                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
 988                                 continue;
 989                         pcpu[i].state = CPU_STATE_STANDBY;
 990                         smp_cpu_set_polarization(cpu + i,
 991                                                  POLARIZATION_UNKNOWN);
 992                 }
 993                 topology_expect_change();
 994                 break;
 995         case 1:
 996                 if (pcpu->state != CPU_STATE_STANDBY)
 997                         break;
 998                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
 999                 if (rc)
1000                         break;
1001                 for (i = 0; i <= smp_cpu_mtid; i++) {
1002                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1003                                 continue;
1004                         pcpu[i].state = CPU_STATE_CONFIGURED;
1005                         smp_cpu_set_polarization(cpu + i,
1006                                                  POLARIZATION_UNKNOWN);
1007                 }
1008                 topology_expect_change();
1009                 break;
1010         default:
1011                 break;
1012         }
1013 out:
1014         mutex_unlock(&smp_cpu_state_mutex);
1015         put_online_cpus();
1016         return rc ? rc : count;
1017 }
1018 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1019 #endif /* CONFIG_HOTPLUG_CPU */
1020
1021 static ssize_t show_cpu_address(struct device *dev,
1022                                 struct device_attribute *attr, char *buf)
1023 {
1024         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1025 }
1026 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1027
1028 static struct attribute *cpu_common_attrs[] = {
1029 #ifdef CONFIG_HOTPLUG_CPU
1030         &dev_attr_configure.attr,
1031 #endif
1032         &dev_attr_address.attr,
1033         NULL,
1034 };
1035
1036 static struct attribute_group cpu_common_attr_group = {
1037         .attrs = cpu_common_attrs,
1038 };
1039
1040 static struct attribute *cpu_online_attrs[] = {
1041         &dev_attr_idle_count.attr,
1042         &dev_attr_idle_time_us.attr,
1043         NULL,
1044 };
1045
1046 static struct attribute_group cpu_online_attr_group = {
1047         .attrs = cpu_online_attrs,
1048 };
1049
1050 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
1051                           void *hcpu)
1052 {
1053         unsigned int cpu = (unsigned int)(long)hcpu;
1054         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1055         int err = 0;
1056
1057         switch (action & ~CPU_TASKS_FROZEN) {
1058         case CPU_ONLINE:
1059                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1060                 break;
1061         case CPU_DEAD:
1062                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1063                 break;
1064         }
1065         return notifier_from_errno(err);
1066 }
1067
1068 static int smp_add_present_cpu(int cpu)
1069 {
1070         struct device *s;
1071         struct cpu *c;
1072         int rc;
1073
1074         c = kzalloc(sizeof(*c), GFP_KERNEL);
1075         if (!c)
1076                 return -ENOMEM;
1077         per_cpu(cpu_device, cpu) = c;
1078         s = &c->dev;
1079         c->hotpluggable = 1;
1080         rc = register_cpu(c, cpu);
1081         if (rc)
1082                 goto out;
1083         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1084         if (rc)
1085                 goto out_cpu;
1086         if (cpu_online(cpu)) {
1087                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1088                 if (rc)
1089                         goto out_online;
1090         }
1091         rc = topology_cpu_init(c);
1092         if (rc)
1093                 goto out_topology;
1094         return 0;
1095
1096 out_topology:
1097         if (cpu_online(cpu))
1098                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1099 out_online:
1100         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1101 out_cpu:
1102 #ifdef CONFIG_HOTPLUG_CPU
1103         unregister_cpu(c);
1104 #endif
1105 out:
1106         return rc;
1107 }
1108
1109 #ifdef CONFIG_HOTPLUG_CPU
1110
1111 int __ref smp_rescan_cpus(void)
1112 {
1113         struct sclp_core_info *info;
1114         int nr;
1115
1116         info = smp_get_core_info();
1117         if (!info)
1118                 return -ENOMEM;
1119         get_online_cpus();
1120         mutex_lock(&smp_cpu_state_mutex);
1121         nr = __smp_rescan_cpus(info, 1);
1122         mutex_unlock(&smp_cpu_state_mutex);
1123         put_online_cpus();
1124         kfree(info);
1125         if (nr)
1126                 topology_schedule_update();
1127         return 0;
1128 }
1129
1130 static ssize_t __ref rescan_store(struct device *dev,
1131                                   struct device_attribute *attr,
1132                                   const char *buf,
1133                                   size_t count)
1134 {
1135         int rc;
1136
1137         rc = smp_rescan_cpus();
1138         return rc ? rc : count;
1139 }
1140 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1141 #endif /* CONFIG_HOTPLUG_CPU */
1142
1143 static int __init s390_smp_init(void)
1144 {
1145         int cpu, rc = 0;
1146
1147 #ifdef CONFIG_HOTPLUG_CPU
1148         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1149         if (rc)
1150                 return rc;
1151 #endif
1152         cpu_notifier_register_begin();
1153         for_each_present_cpu(cpu) {
1154                 rc = smp_add_present_cpu(cpu);
1155                 if (rc)
1156                         goto out;
1157         }
1158
1159         __hotcpu_notifier(smp_cpu_notify, 0);
1160
1161 out:
1162         cpu_notifier_register_done();
1163         return rc;
1164 }
1165 subsys_initcall(s390_smp_init);