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/switch_to.h>
  37 #include <asm/facility.h>
  38 #include <asm/ipl.h>
  39 #include <asm/setup.h>
  40 #include <asm/irq.h>
  41 #include <asm/tlbflush.h>
  42 #include <asm/vtimer.h>
  43 #include <asm/lowcore.h>
  44 #include <asm/sclp.h>
  45 #include <asm/vdso.h>
  46 #include <asm/debug.h>
  47 #include <asm/os_info.h>
  48 #include <asm/sigp.h>
  49 #include <asm/idle.h>
  50 #include "entry.h"
  51
  52 enum {
  53         ec_schedule = 0,
  54         ec_call_function_single,
  55         ec_stop_cpu,
  56 };
  57
  58 enum {
  59         CPU_STATE_STANDBY,
  60         CPU_STATE_CONFIGURED,
  61 };
  62
  63 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  64
  65 struct pcpu {
  66         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
  67         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  68         signed char state;              /* physical cpu state */
  69         signed char polarization;       /* physical polarization */
  70         u16 address;                    /* physical cpu address */
  71 };
  72
  73 static u8 boot_core_type;
  74 static struct pcpu pcpu_devices[NR_CPUS];
  75
  76 unsigned int smp_cpu_mt_shift;
  77 EXPORT_SYMBOL(smp_cpu_mt_shift);
  78
  79 unsigned int smp_cpu_mtid;
  80 EXPORT_SYMBOL(smp_cpu_mtid);
  81
  82 static unsigned int smp_max_threads __initdata = -1U;
  83
  84 static int __init early_nosmt(char *s)
  85 {
  86         smp_max_threads = 1;
  87         return 0;
  88 }
  89 early_param("nosmt", early_nosmt);
  90
  91 static int __init early_smt(char *s)
  92 {
  93         get_option(&s, &smp_max_threads);
  94         return 0;
  95 }
  96 early_param("smt", early_smt);
  97
  98 /*
  99  * The smp_cpu_state_mutex must be held when changing the state or polarization
 100  * member of a pcpu data structure within the pcpu_devices arreay.
 101  */
 102 DEFINE_MUTEX(smp_cpu_state_mutex);
 103
 104 /*
 105  * Signal processor helper functions.
 106  */
 107 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm,
 108                                     u32 *status)
 109 {
 110         int cc;
 111
 112         while (1) {
 113                 cc = __pcpu_sigp(addr, order, parm, NULL);
 114                 if (cc != SIGP_CC_BUSY)
 115                         return cc;
 116                 cpu_relax();
 117         }
 118 }
 119
 120 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 121 {
 122         int cc, retry;
 123
 124         for (retry = 0; ; retry++) {
 125                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 126                 if (cc != SIGP_CC_BUSY)
 127                         break;
 128                 if (retry >= 3)
 129                         udelay(10);
 130         }
 131         return cc;
 132 }
 133
 134 static inline int pcpu_stopped(struct pcpu *pcpu)
 135 {
 136         u32 uninitialized_var(status);
 137
 138         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 139                         0, &status) != SIGP_CC_STATUS_STORED)
 140                 return 0;
 141         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 142 }
 143
 144 static inline int pcpu_running(struct pcpu *pcpu)
 145 {
 146         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 147                         0, NULL) != SIGP_CC_STATUS_STORED)
 148                 return 1;
 149         /* Status stored condition code is equivalent to cpu not running. */
 150         return 0;
 151 }
 152
 153 /*
 154  * Find struct pcpu by cpu address.
 155  */
 156 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 157 {
 158         int cpu;
 159
 160         for_each_cpu(cpu, mask)
 161                 if (pcpu_devices[cpu].address == address)
 162                         return pcpu_devices + cpu;
 163         return NULL;
 164 }
 165
 166 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 167 {
 168         int order;
 169
 170         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 171                 return;
 172         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 173         pcpu_sigp_retry(pcpu, order, 0);
 174 }
 175
 176 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 177 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 178
 179 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 180 {
 181         unsigned long async_stack, panic_stack;
 182         struct _lowcore *lc;
 183
 184         if (pcpu != &pcpu_devices[0]) {
 185                 pcpu->lowcore = (struct _lowcore *)
 186                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 187                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 188                 panic_stack = __get_free_page(GFP_KERNEL);
 189                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 190                         goto out;
 191         } else {
 192                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 193                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 194         }
 195         lc = pcpu->lowcore;
 196         memcpy(lc, &S390_lowcore, 512);
 197         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 198         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 199         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 200         lc->cpu_nr = cpu;
 201         lc->spinlock_lockval = arch_spin_lockval(cpu);
 202         if (MACHINE_HAS_VX)
 203                 lc->vector_save_area_addr =
 204                         (unsigned long) &lc->vector_save_area;
 205         if (vdso_alloc_per_cpu(lc))
 206                 goto out;
 207         lowcore_ptr[cpu] = lc;
 208         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 209         return 0;
 210 out:
 211         if (pcpu != &pcpu_devices[0]) {
 212                 free_page(panic_stack);
 213                 free_pages(async_stack, ASYNC_ORDER);
 214                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 215         }
 216         return -ENOMEM;
 217 }
 218
 219 #ifdef CONFIG_HOTPLUG_CPU
 220
 221 static void pcpu_free_lowcore(struct pcpu *pcpu)
 222 {
 223         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 224         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 225         vdso_free_per_cpu(pcpu->lowcore);
 226         if (pcpu == &pcpu_devices[0])
 227                 return;
 228         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 229         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 230         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 231 }
 232
 233 #endif /* CONFIG_HOTPLUG_CPU */
 234
 235 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 236 {
 237         struct _lowcore *lc = pcpu->lowcore;
 238
 239         if (MACHINE_HAS_TLB_LC)
 240                 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 241         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 242         atomic_inc(&init_mm.context.attach_count);
 243         lc->cpu_nr = cpu;
 244         lc->spinlock_lockval = arch_spin_lockval(cpu);
 245         lc->percpu_offset = __per_cpu_offset[cpu];
 246         lc->kernel_asce = S390_lowcore.kernel_asce;
 247         lc->machine_flags = S390_lowcore.machine_flags;
 248         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 249         __ctl_store(lc->cregs_save_area, 0, 15);
 250         save_access_regs((unsigned int *) lc->access_regs_save_area);
 251         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 252                MAX_FACILITY_BIT/8);
 253 }
 254
 255 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 256 {
 257         struct _lowcore *lc = pcpu->lowcore;
 258         struct thread_info *ti = task_thread_info(tsk);
 259
 260         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 261                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 262         lc->thread_info = (unsigned long) task_thread_info(tsk);
 263         lc->current_task = (unsigned long) tsk;
 264         lc->user_timer = ti->user_timer;
 265         lc->system_timer = ti->system_timer;
 266         lc->steal_timer = 0;
 267 }
 268
 269 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 270 {
 271         struct _lowcore *lc = pcpu->lowcore;
 272
 273         lc->restart_stack = lc->kernel_stack;
 274         lc->restart_fn = (unsigned long) func;
 275         lc->restart_data = (unsigned long) data;
 276         lc->restart_source = -1UL;
 277         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 278 }
 279
 280 /*
 281  * Call function via PSW restart on pcpu and stop the current cpu.
 282  */
 283 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 284                           void *data, unsigned long stack)
 285 {
 286         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 287         unsigned long source_cpu = stap();
 288
 289         __load_psw_mask(PSW_KERNEL_BITS);
 290         if (pcpu->address == source_cpu)
 291                 func(data);     /* should not return */
 292         /* Stop target cpu (if func returns this stops the current cpu). */
 293         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 294         /* Restart func on the target cpu and stop the current cpu. */
 295         mem_assign_absolute(lc->restart_stack, stack);
 296         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 297         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 298         mem_assign_absolute(lc->restart_source, source_cpu);
 299         asm volatile(
 300                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 301                 "       brc     2,0b    # busy, try again\n"
 302                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 303                 "       brc     2,1b    # busy, try again\n"
 304                 : : "d" (pcpu->address), "d" (source_cpu),
 305                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 306                 : "0", "1", "cc");
 307         for (;;) ;
 308 }
 309
 310 /*
 311  * Enable additional logical cpus for multi-threading.
 312  */
 313 static int pcpu_set_smt(unsigned int mtid)
 314 {
 315         register unsigned long reg1 asm ("1") = (unsigned long) mtid;
 316         int cc;
 317
 318         if (smp_cpu_mtid == mtid)
 319                 return 0;
 320         asm volatile(
 321                 "       sigp    %1,0,%2 # sigp set multi-threading\n"
 322                 "       ipm     %0\n"
 323                 "       srl     %0,28\n"
 324                 : "=d" (cc) : "d" (reg1), "K" (SIGP_SET_MULTI_THREADING)
 325                 : "cc");
 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                 asm volatile("diag %0,0,0x9c"
 380                              : : "d" (pcpu_devices[cpu].address));
 381         else if (MACHINE_HAS_DIAG44)
 382                 asm volatile("diag 0,0,0x44");
 383 }
 384
 385 /*
 386  * Send cpus emergency shutdown signal. This gives the cpus the
 387  * opportunity to complete outstanding interrupts.
 388  */
 389 static void smp_emergency_stop(cpumask_t *cpumask)
 390 {
 391         u64 end;
 392         int cpu;
 393
 394         end = get_tod_clock() + (1000000UL << 12);
 395         for_each_cpu(cpu, cpumask) {
 396                 struct pcpu *pcpu = pcpu_devices + cpu;
 397                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 398                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 399                                    0, NULL) == SIGP_CC_BUSY &&
 400                        get_tod_clock() < end)
 401                         cpu_relax();
 402         }
 403         while (get_tod_clock() < end) {
 404                 for_each_cpu(cpu, cpumask)
 405                         if (pcpu_stopped(pcpu_devices + cpu))
 406                                 cpumask_clear_cpu(cpu, cpumask);
 407                 if (cpumask_empty(cpumask))
 408                         break;
 409                 cpu_relax();
 410         }
 411 }
 412
 413 /*
 414  * Stop all cpus but the current one.
 415  */
 416 void smp_send_stop(void)
 417 {
 418         cpumask_t cpumask;
 419         int cpu;
 420
 421         /* Disable all interrupts/machine checks */
 422         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 423         trace_hardirqs_off();
 424
 425         debug_set_critical();
 426         cpumask_copy(&cpumask, cpu_online_mask);
 427         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 428
 429         if (oops_in_progress)
 430                 smp_emergency_stop(&cpumask);
 431
 432         /* stop all processors */
 433         for_each_cpu(cpu, &cpumask) {
 434                 struct pcpu *pcpu = pcpu_devices + cpu;
 435                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 436                 while (!pcpu_stopped(pcpu))
 437                         cpu_relax();
 438         }
 439 }
 440
 441 /*
 442  * This is the main routine where commands issued by other
 443  * cpus are handled.
 444  */
 445 static void smp_handle_ext_call(void)
 446 {
 447         unsigned long bits;
 448
 449         /* handle bit signal external calls */
 450         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 451         if (test_bit(ec_stop_cpu, &bits))
 452                 smp_stop_cpu();
 453         if (test_bit(ec_schedule, &bits))
 454                 scheduler_ipi();
 455         if (test_bit(ec_call_function_single, &bits))
 456                 generic_smp_call_function_single_interrupt();
 457 }
 458
 459 static void do_ext_call_interrupt(struct ext_code ext_code,
 460                                   unsigned int param32, unsigned long param64)
 461 {
 462         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 463         smp_handle_ext_call();
 464 }
 465
 466 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 467 {
 468         int cpu;
 469
 470         for_each_cpu(cpu, mask)
 471                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 472 }
 473
 474 void arch_send_call_function_single_ipi(int cpu)
 475 {
 476         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 477 }
 478
 479 /*
 480  * this function sends a 'reschedule' IPI to another CPU.
 481  * it goes straight through and wastes no time serializing
 482  * anything. Worst case is that we lose a reschedule ...
 483  */
 484 void smp_send_reschedule(int cpu)
 485 {
 486         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 487 }
 488
 489 /*
 490  * parameter area for the set/clear control bit callbacks
 491  */
 492 struct ec_creg_mask_parms {
 493         unsigned long orval;
 494         unsigned long andval;
 495         int cr;
 496 };
 497
 498 /*
 499  * callback for setting/clearing control bits
 500  */
 501 static void smp_ctl_bit_callback(void *info)
 502 {
 503         struct ec_creg_mask_parms *pp = info;
 504         unsigned long cregs[16];
 505
 506         __ctl_store(cregs, 0, 15);
 507         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 508         __ctl_load(cregs, 0, 15);
 509 }
 510
 511 /*
 512  * Set a bit in a control register of all cpus
 513  */
 514 void smp_ctl_set_bit(int cr, int bit)
 515 {
 516         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 517
 518         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 519 }
 520 EXPORT_SYMBOL(smp_ctl_set_bit);
 521
 522 /*
 523  * Clear a bit in a control register of all cpus
 524  */
 525 void smp_ctl_clear_bit(int cr, int bit)
 526 {
 527         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 528
 529         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 530 }
 531 EXPORT_SYMBOL(smp_ctl_clear_bit);
 532
 533 #ifdef CONFIG_CRASH_DUMP
 534
 535 static void __init __smp_store_cpu_state(struct save_area_ext *sa_ext,
 536                                          u16 address, int is_boot_cpu)
 537 {
 538         void *lc = (void *)(unsigned long) store_prefix();
 539         unsigned long vx_sa;
 540
 541         if (is_boot_cpu) {
 542                 /* Copy the registers of the boot CPU. */
 543                 copy_oldmem_page(1, (void *) &sa_ext->sa, sizeof(sa_ext->sa),
 544                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 545                 if (MACHINE_HAS_VX)
 546                         save_vx_regs_safe(sa_ext->vx_regs);
 547                 return;
 548         }
 549         /* Get the registers of a non-boot cpu. */
 550         __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
 551         memcpy_real(&sa_ext->sa, lc + SAVE_AREA_BASE, sizeof(sa_ext->sa));
 552         if (!MACHINE_HAS_VX)
 553                 return;
 554         /* Get the VX registers */
 555         vx_sa = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 556         if (!vx_sa)
 557                 panic("could not allocate memory for VX save area\n");
 558         __pcpu_sigp_relax(address, SIGP_STORE_ADDITIONAL_STATUS, vx_sa, NULL);
 559         memcpy(sa_ext->vx_regs, (void *) vx_sa, sizeof(sa_ext->vx_regs));
 560         memblock_free(vx_sa, PAGE_SIZE);
 561 }
 562
 563 int smp_store_status(int cpu)
 564 {
 565         unsigned long vx_sa;
 566         struct pcpu *pcpu;
 567
 568         pcpu = pcpu_devices + cpu;
 569         if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
 570                               0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
 571                 return -EIO;
 572         if (!MACHINE_HAS_VX)
 573                 return 0;
 574         vx_sa = __pa(pcpu->lowcore->vector_save_area_addr);
 575         __pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 576                           vx_sa, NULL);
 577         return 0;
 578 }
 579
 580 #endif /* CONFIG_CRASH_DUMP */
 581
 582 /*
 583  * Collect CPU state of the previous, crashed system.
 584  * There are four cases:
 585  * 1) standard zfcp dump
 586  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 587  *    The state for all CPUs except the boot CPU needs to be collected
 588  *    with sigp stop-and-store-status. The boot CPU state is located in
 589  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 590  *    will allocate the save area and copy the boot CPU state from the HSA.
 591  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 592  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 593  *    The state for all CPUs except the boot CPU needs to be collected
 594  *    with sigp stop-and-store-status. The firmware or the boot-loader
 595  *    stored the registers of the boot CPU in the absolute lowcore in the
 596  *    memory of the old system.
 597  * 3) kdump and the old kernel did not store the CPU state,
 598  *    or stand-alone kdump for DASD
 599  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 600  *    The state for all CPUs except the boot CPU needs to be collected
 601  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 602  *    stored the registers of the boot CPU in the memory of the old system.
 603  * 4) kdump and the old kernel stored the CPU state
 604  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 605  *    The state of all CPUs is stored in ELF sections in the memory of the
 606  *    old system. The ELF sections are picked up by the crash_dump code
 607  *    via elfcorehdr_addr.
 608  */
 609 void __init smp_save_dump_cpus(void)
 610 {
 611 #ifdef CONFIG_CRASH_DUMP
 612         int addr, cpu, boot_cpu_addr, max_cpu_addr;
 613         struct save_area_ext *sa_ext;
 614         bool is_boot_cpu;
 615
 616         if (is_kdump_kernel())
 617                 /* Previous system stored the CPU states. Nothing to do. */
 618                 return;
 619         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 620                 /* No previous system present, normal boot. */
 621                 return;
 622         /* Set multi-threading state to the previous system. */
 623         pcpu_set_smt(sclp.mtid_prev);
 624         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 625         for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
 626                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
 627                     SIGP_CC_NOT_OPERATIONAL)
 628                         continue;
 629                 cpu += 1;
 630         }
 631         dump_save_areas.areas = (void *)memblock_alloc(sizeof(void *) * cpu, 8);
 632         dump_save_areas.count = cpu;
 633         boot_cpu_addr = stap();
 634         for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
 635                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
 636                     SIGP_CC_NOT_OPERATIONAL)
 637                         continue;
 638                 sa_ext = (void *) memblock_alloc(sizeof(*sa_ext), 8);
 639                 dump_save_areas.areas[cpu] = sa_ext;
 640                 if (!sa_ext)
 641                         panic("could not allocate memory for save area\n");
 642                 is_boot_cpu = (addr == boot_cpu_addr);
 643                 cpu += 1;
 644                 if (is_boot_cpu && !OLDMEM_BASE)
 645                         /* Skip boot CPU for standard zfcp dump. */
 646                         continue;
 647                 /* Get state for this CPU. */
 648                 __smp_store_cpu_state(sa_ext, addr, is_boot_cpu);
 649         }
 650         diag308_reset();
 651         pcpu_set_smt(0);
 652 #endif /* CONFIG_CRASH_DUMP */
 653 }
 654
 655 void smp_cpu_set_polarization(int cpu, int val)
 656 {
 657         pcpu_devices[cpu].polarization = val;
 658 }
 659
 660 int smp_cpu_get_polarization(int cpu)
 661 {
 662         return pcpu_devices[cpu].polarization;
 663 }
 664
 665 static struct sclp_core_info *smp_get_core_info(void)
 666 {
 667         static int use_sigp_detection;
 668         struct sclp_core_info *info;
 669         int address;
 670
 671         info = kzalloc(sizeof(*info), GFP_KERNEL);
 672         if (info && (use_sigp_detection || sclp_get_core_info(info))) {
 673                 use_sigp_detection = 1;
 674                 for (address = 0;
 675                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 676                      address += (1U << smp_cpu_mt_shift)) {
 677                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 678                             SIGP_CC_NOT_OPERATIONAL)
 679                                 continue;
 680                         info->core[info->configured].core_id =
 681                                 address >> smp_cpu_mt_shift;
 682                         info->configured++;
 683                 }
 684                 info->combined = info->configured;
 685         }
 686         return info;
 687 }
 688
 689 static int smp_add_present_cpu(int cpu);
 690
 691 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 692 {
 693         struct pcpu *pcpu;
 694         cpumask_t avail;
 695         int cpu, nr, i, j;
 696         u16 address;
 697
 698         nr = 0;
 699         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 700         cpu = cpumask_first(&avail);
 701         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 702                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 703                         continue;
 704                 address = info->core[i].core_id << smp_cpu_mt_shift;
 705                 for (j = 0; j <= smp_cpu_mtid; j++) {
 706                         if (pcpu_find_address(cpu_present_mask, address + j))
 707                                 continue;
 708                         pcpu = pcpu_devices + cpu;
 709                         pcpu->address = address + j;
 710                         pcpu->state =
 711                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 712                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 713                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 714                         set_cpu_present(cpu, true);
 715                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 716                                 set_cpu_present(cpu, false);
 717                         else
 718                                 nr++;
 719                         cpu = cpumask_next(cpu, &avail);
 720                         if (cpu >= nr_cpu_ids)
 721                                 break;
 722                 }
 723         }
 724         return nr;
 725 }
 726
 727 static void __init smp_detect_cpus(void)
 728 {
 729         unsigned int cpu, mtid, c_cpus, s_cpus;
 730         struct sclp_core_info *info;
 731         u16 address;
 732
 733         /* Get CPU information */
 734         info = smp_get_core_info();
 735         if (!info)
 736                 panic("smp_detect_cpus failed to allocate memory\n");
 737
 738         /* Find boot CPU type */
 739         if (sclp.has_core_type) {
 740                 address = stap();
 741                 for (cpu = 0; cpu < info->combined; cpu++)
 742                         if (info->core[cpu].core_id == address) {
 743                                 /* The boot cpu dictates the cpu type. */
 744                                 boot_core_type = info->core[cpu].type;
 745                                 break;
 746                         }
 747                 if (cpu >= info->combined)
 748                         panic("Could not find boot CPU type");
 749         }
 750
 751         /* Set multi-threading state for the current system */
 752         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 753         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 754         pcpu_set_smt(mtid);
 755
 756         /* Print number of CPUs */
 757         c_cpus = s_cpus = 0;
 758         for (cpu = 0; cpu < info->combined; cpu++) {
 759                 if (sclp.has_core_type &&
 760                     info->core[cpu].type != boot_core_type)
 761                         continue;
 762                 if (cpu < info->configured)
 763                         c_cpus += smp_cpu_mtid + 1;
 764                 else
 765                         s_cpus += smp_cpu_mtid + 1;
 766         }
 767         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 768
 769         /* Add CPUs present at boot */
 770         get_online_cpus();
 771         __smp_rescan_cpus(info, 0);
 772         put_online_cpus();
 773         kfree(info);
 774 }
 775
 776 /*
 777  *      Activate a secondary processor.
 778  */
 779 static void smp_start_secondary(void *cpuvoid)
 780 {
 781         S390_lowcore.last_update_clock = get_tod_clock();
 782         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 783         S390_lowcore.restart_fn = (unsigned long) do_restart;
 784         S390_lowcore.restart_data = 0;
 785         S390_lowcore.restart_source = -1UL;
 786         restore_access_regs(S390_lowcore.access_regs_save_area);
 787         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 788         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 789         cpu_init();
 790         preempt_disable();
 791         init_cpu_timer();
 792         vtime_init();
 793         pfault_init();
 794         notify_cpu_starting(smp_processor_id());
 795         set_cpu_online(smp_processor_id(), true);
 796         inc_irq_stat(CPU_RST);
 797         local_irq_enable();
 798         cpu_startup_entry(CPUHP_ONLINE);
 799 }
 800
 801 /* Upping and downing of CPUs */
 802 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 803 {
 804         struct pcpu *pcpu;
 805         int base, i, rc;
 806
 807         pcpu = pcpu_devices + cpu;
 808         if (pcpu->state != CPU_STATE_CONFIGURED)
 809                 return -EIO;
 810         base = cpu - (cpu % (smp_cpu_mtid + 1));
 811         for (i = 0; i <= smp_cpu_mtid; i++) {
 812                 if (base + i < nr_cpu_ids)
 813                         if (cpu_online(base + i))
 814                                 break;
 815         }
 816         /*
 817          * If this is the first CPU of the core to get online
 818          * do an initial CPU reset.
 819          */
 820         if (i > smp_cpu_mtid &&
 821             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 822             SIGP_CC_ORDER_CODE_ACCEPTED)
 823                 return -EIO;
 824
 825         rc = pcpu_alloc_lowcore(pcpu, cpu);
 826         if (rc)
 827                 return rc;
 828         pcpu_prepare_secondary(pcpu, cpu);
 829         pcpu_attach_task(pcpu, tidle);
 830         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 831         /* Wait until cpu puts itself in the online & active maps */
 832         while (!cpu_online(cpu) || !cpu_active(cpu))
 833                 cpu_relax();
 834         return 0;
 835 }
 836
 837 static unsigned int setup_possible_cpus __initdata;
 838
 839 static int __init _setup_possible_cpus(char *s)
 840 {
 841         get_option(&s, &setup_possible_cpus);
 842         return 0;
 843 }
 844 early_param("possible_cpus", _setup_possible_cpus);
 845
 846 #ifdef CONFIG_HOTPLUG_CPU
 847
 848 int __cpu_disable(void)
 849 {
 850         unsigned long cregs[16];
 851
 852         /* Handle possible pending IPIs */
 853         smp_handle_ext_call();
 854         set_cpu_online(smp_processor_id(), false);
 855         /* Disable pseudo page faults on this cpu. */
 856         pfault_fini();
 857         /* Disable interrupt sources via control register. */
 858         __ctl_store(cregs, 0, 15);
 859         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 860         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 861         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 862         __ctl_load(cregs, 0, 15);
 863         clear_cpu_flag(CIF_NOHZ_DELAY);
 864         return 0;
 865 }
 866
 867 void __cpu_die(unsigned int cpu)
 868 {
 869         struct pcpu *pcpu;
 870
 871         /* Wait until target cpu is down */
 872         pcpu = pcpu_devices + cpu;
 873         while (!pcpu_stopped(pcpu))
 874                 cpu_relax();
 875         pcpu_free_lowcore(pcpu);
 876         atomic_dec(&init_mm.context.attach_count);
 877         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 878         if (MACHINE_HAS_TLB_LC)
 879                 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 880 }
 881
 882 void __noreturn cpu_die(void)
 883 {
 884         idle_task_exit();
 885         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 886         for (;;) ;
 887 }
 888
 889 #endif /* CONFIG_HOTPLUG_CPU */
 890
 891 void __init smp_fill_possible_mask(void)
 892 {
 893         unsigned int possible, sclp_max, cpu;
 894
 895         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 896         sclp_max = min(smp_max_threads, sclp_max);
 897         sclp_max = sclp.max_cores * sclp_max ?: nr_cpu_ids;
 898         possible = setup_possible_cpus ?: nr_cpu_ids;
 899         possible = min(possible, sclp_max);
 900         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 901                 set_cpu_possible(cpu, true);
 902 }
 903
 904 void __init smp_prepare_cpus(unsigned int max_cpus)
 905 {
 906         /* request the 0x1201 emergency signal external interrupt */
 907         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 908                 panic("Couldn't request external interrupt 0x1201");
 909         /* request the 0x1202 external call external interrupt */
 910         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 911                 panic("Couldn't request external interrupt 0x1202");
 912         smp_detect_cpus();
 913 }
 914
 915 void __init smp_prepare_boot_cpu(void)
 916 {
 917         struct pcpu *pcpu = pcpu_devices;
 918
 919         pcpu->state = CPU_STATE_CONFIGURED;
 920         pcpu->address = stap();
 921         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 922         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 923         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 924         set_cpu_present(0, true);
 925         set_cpu_online(0, true);
 926 }
 927
 928 void __init smp_cpus_done(unsigned int max_cpus)
 929 {
 930 }
 931
 932 void __init smp_setup_processor_id(void)
 933 {
 934         S390_lowcore.cpu_nr = 0;
 935         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 936 }
 937
 938 /*
 939  * the frequency of the profiling timer can be changed
 940  * by writing a multiplier value into /proc/profile.
 941  *
 942  * usually you want to run this on all CPUs ;)
 943  */
 944 int setup_profiling_timer(unsigned int multiplier)
 945 {
 946         return 0;
 947 }
 948
 949 #ifdef CONFIG_HOTPLUG_CPU
 950 static ssize_t cpu_configure_show(struct device *dev,
 951                                   struct device_attribute *attr, char *buf)
 952 {
 953         ssize_t count;
 954
 955         mutex_lock(&smp_cpu_state_mutex);
 956         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 957         mutex_unlock(&smp_cpu_state_mutex);
 958         return count;
 959 }
 960
 961 static ssize_t cpu_configure_store(struct device *dev,
 962                                    struct device_attribute *attr,
 963                                    const char *buf, size_t count)
 964 {
 965         struct pcpu *pcpu;
 966         int cpu, val, rc, i;
 967         char delim;
 968
 969         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 970                 return -EINVAL;
 971         if (val != 0 && val != 1)
 972                 return -EINVAL;
 973         get_online_cpus();
 974         mutex_lock(&smp_cpu_state_mutex);
 975         rc = -EBUSY;
 976         /* disallow configuration changes of online cpus and cpu 0 */
 977         cpu = dev->id;
 978         cpu -= cpu % (smp_cpu_mtid + 1);
 979         if (cpu == 0)
 980                 goto out;
 981         for (i = 0; i <= smp_cpu_mtid; i++)
 982                 if (cpu_online(cpu + i))
 983                         goto out;
 984         pcpu = pcpu_devices + cpu;
 985         rc = 0;
 986         switch (val) {
 987         case 0:
 988                 if (pcpu->state != CPU_STATE_CONFIGURED)
 989                         break;
 990                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
 991                 if (rc)
 992                         break;
 993                 for (i = 0; i <= smp_cpu_mtid; i++) {
 994                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
 995                                 continue;
 996                         pcpu[i].state = CPU_STATE_STANDBY;
 997                         smp_cpu_set_polarization(cpu + i,
 998                                                  POLARIZATION_UNKNOWN);
 999                 }
1000                 topology_expect_change();
1001                 break;
1002         case 1:
1003                 if (pcpu->state != CPU_STATE_STANDBY)
1004                         break;
1005                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1006                 if (rc)
1007                         break;
1008                 for (i = 0; i <= smp_cpu_mtid; i++) {
1009                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1010                                 continue;
1011                         pcpu[i].state = CPU_STATE_CONFIGURED;
1012                         smp_cpu_set_polarization(cpu + i,
1013                                                  POLARIZATION_UNKNOWN);
1014                 }
1015                 topology_expect_change();
1016                 break;
1017         default:
1018                 break;
1019         }
1020 out:
1021         mutex_unlock(&smp_cpu_state_mutex);
1022         put_online_cpus();
1023         return rc ? rc : count;
1024 }
1025 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1026 #endif /* CONFIG_HOTPLUG_CPU */
1027
1028 static ssize_t show_cpu_address(struct device *dev,
1029                                 struct device_attribute *attr, char *buf)
1030 {
1031         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1032 }
1033 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1034
1035 static struct attribute *cpu_common_attrs[] = {
1036 #ifdef CONFIG_HOTPLUG_CPU
1037         &dev_attr_configure.attr,
1038 #endif
1039         &dev_attr_address.attr,
1040         NULL,
1041 };
1042
1043 static struct attribute_group cpu_common_attr_group = {
1044         .attrs = cpu_common_attrs,
1045 };
1046
1047 static struct attribute *cpu_online_attrs[] = {
1048         &dev_attr_idle_count.attr,
1049         &dev_attr_idle_time_us.attr,
1050         NULL,
1051 };
1052
1053 static struct attribute_group cpu_online_attr_group = {
1054         .attrs = cpu_online_attrs,
1055 };
1056
1057 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
1058                           void *hcpu)
1059 {
1060         unsigned int cpu = (unsigned int)(long)hcpu;
1061         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1062         int err = 0;
1063
1064         switch (action & ~CPU_TASKS_FROZEN) {
1065         case CPU_ONLINE:
1066                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1067                 break;
1068         case CPU_DEAD:
1069                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1070                 break;
1071         }
1072         return notifier_from_errno(err);
1073 }
1074
1075 static int smp_add_present_cpu(int cpu)
1076 {
1077         struct device *s;
1078         struct cpu *c;
1079         int rc;
1080
1081         c = kzalloc(sizeof(*c), GFP_KERNEL);
1082         if (!c)
1083                 return -ENOMEM;
1084         per_cpu(cpu_device, cpu) = c;
1085         s = &c->dev;
1086         c->hotpluggable = 1;
1087         rc = register_cpu(c, cpu);
1088         if (rc)
1089                 goto out;
1090         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1091         if (rc)
1092                 goto out_cpu;
1093         if (cpu_online(cpu)) {
1094                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1095                 if (rc)
1096                         goto out_online;
1097         }
1098         rc = topology_cpu_init(c);
1099         if (rc)
1100                 goto out_topology;
1101         return 0;
1102
1103 out_topology:
1104         if (cpu_online(cpu))
1105                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1106 out_online:
1107         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1108 out_cpu:
1109 #ifdef CONFIG_HOTPLUG_CPU
1110         unregister_cpu(c);
1111 #endif
1112 out:
1113         return rc;
1114 }
1115
1116 #ifdef CONFIG_HOTPLUG_CPU
1117
1118 int __ref smp_rescan_cpus(void)
1119 {
1120         struct sclp_core_info *info;
1121         int nr;
1122
1123         info = smp_get_core_info();
1124         if (!info)
1125                 return -ENOMEM;
1126         get_online_cpus();
1127         mutex_lock(&smp_cpu_state_mutex);
1128         nr = __smp_rescan_cpus(info, 1);
1129         mutex_unlock(&smp_cpu_state_mutex);
1130         put_online_cpus();
1131         kfree(info);
1132         if (nr)
1133                 topology_schedule_update();
1134         return 0;
1135 }
1136
1137 static ssize_t __ref rescan_store(struct device *dev,
1138                                   struct device_attribute *attr,
1139                                   const char *buf,
1140                                   size_t count)
1141 {
1142         int rc;
1143
1144         rc = smp_rescan_cpus();
1145         return rc ? rc : count;
1146 }
1147 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1148 #endif /* CONFIG_HOTPLUG_CPU */
1149
1150 static int __init s390_smp_init(void)
1151 {
1152         int cpu, rc = 0;
1153
1154 #ifdef CONFIG_HOTPLUG_CPU
1155         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1156         if (rc)
1157                 return rc;
1158 #endif
1159         cpu_notifier_register_begin();
1160         for_each_present_cpu(cpu) {
1161                 rc = smp_add_present_cpu(cpu);
1162                 if (rc)
1163                         goto out;
1164         }
1165
1166         __hotcpu_notifier(smp_cpu_notify, 0);
1167
1168 out:
1169         cpu_notifier_register_done();
1170         return rc;
1171 }
1172 subsys_initcall(s390_smp_init);