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