arch/mips/kernel/smp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) 2000, 2001 Kanoj Sarcar
   5  * Copyright (C) 2000, 2001 Ralf Baechle
   6  * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
   7  * Copyright (C) 2000, 2001, 2003 Broadcom Corporation
   8  */
   9 #include <linux/cache.h>
  10 #include <linux/delay.h>
  11 #include <linux/init.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/smp.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/threads.h>
  16 #include <linux/export.h>
  17 #include <linux/time.h>
  18 #include <linux/timex.h>
  19 #include <linux/sched/mm.h>
  20 #include <linux/cpumask.h>
  21 #include <linux/cpu.h>
  22 #include <linux/err.h>
  23 #include <linux/ftrace.h>
  24 #include <linux/irqdomain.h>
  25 #include <linux/of.h>
  26 #include <linux/of_irq.h>
  27
  28 #include <linux/atomic.h>
  29 #include <asm/cpu.h>
  30 #include <asm/ginvt.h>
  31 #include <asm/processor.h>
  32 #include <asm/idle.h>
  33 #include <asm/r4k-timer.h>
  34 #include <asm/mips-cps.h>
  35 #include <asm/mmu_context.h>
  36 #include <asm/time.h>
  37 #include <asm/setup.h>
  38 #include <asm/maar.h>
  39
  40 int __cpu_number_map[CONFIG_MIPS_NR_CPU_NR_MAP];   /* Map physical to logical */
  41 EXPORT_SYMBOL(__cpu_number_map);
  42
  43 int __cpu_logical_map[NR_CPUS];         /* Map logical to physical */
  44 EXPORT_SYMBOL(__cpu_logical_map);
  45
  46 /* Number of TCs (or siblings in Intel speak) per CPU core */
  47 int smp_num_siblings = 1;
  48 EXPORT_SYMBOL(smp_num_siblings);
  49
  50 /* representing the TCs (or siblings in Intel speak) of each logical CPU */
  51 cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;
  52 EXPORT_SYMBOL(cpu_sibling_map);
  53
  54 /* representing the core map of multi-core chips of each logical CPU */
  55 cpumask_t cpu_core_map[NR_CPUS] __read_mostly;
  56 EXPORT_SYMBOL(cpu_core_map);
  57
  58 static DECLARE_COMPLETION(cpu_starting);
  59 static DECLARE_COMPLETION(cpu_running);
  60
  61 /*
  62  * A logcal cpu mask containing only one VPE per core to
  63  * reduce the number of IPIs on large MT systems.
  64  */
  65 cpumask_t cpu_foreign_map[NR_CPUS] __read_mostly;
  66 EXPORT_SYMBOL(cpu_foreign_map);
  67
  68 /* representing cpus for which sibling maps can be computed */
  69 static cpumask_t cpu_sibling_setup_map;
  70
  71 /* representing cpus for which core maps can be computed */
  72 static cpumask_t cpu_core_setup_map;
  73
  74 cpumask_t cpu_coherent_mask;
  75
  76 #ifdef CONFIG_GENERIC_IRQ_IPI
  77 static struct irq_desc *call_desc;
  78 static struct irq_desc *sched_desc;
  79 #endif
  80
  81 static inline void set_cpu_sibling_map(int cpu)
  82 {
  83         int i;
  84
  85         cpumask_set_cpu(cpu, &cpu_sibling_setup_map);
  86
  87         if (smp_num_siblings > 1) {
  88                 for_each_cpu(i, &cpu_sibling_setup_map) {
  89                         if (cpus_are_siblings(cpu, i)) {
  90                                 cpumask_set_cpu(i, &cpu_sibling_map[cpu]);
  91                                 cpumask_set_cpu(cpu, &cpu_sibling_map[i]);
  92                         }
  93                 }
  94         } else
  95                 cpumask_set_cpu(cpu, &cpu_sibling_map[cpu]);
  96 }
  97
  98 static inline void set_cpu_core_map(int cpu)
  99 {
 100         int i;
 101
 102         cpumask_set_cpu(cpu, &cpu_core_setup_map);
 103
 104         for_each_cpu(i, &cpu_core_setup_map) {
 105                 if (cpu_data[cpu].package == cpu_data[i].package) {
 106                         cpumask_set_cpu(i, &cpu_core_map[cpu]);
 107                         cpumask_set_cpu(cpu, &cpu_core_map[i]);
 108                 }
 109         }
 110 }
 111
 112 /*
 113  * Calculate a new cpu_foreign_map mask whenever a
 114  * new cpu appears or disappears.
 115  */
 116 void calculate_cpu_foreign_map(void)
 117 {
 118         int i, k, core_present;
 119         cpumask_t temp_foreign_map;
 120
 121         /* Re-calculate the mask */
 122         cpumask_clear(&temp_foreign_map);
 123         for_each_online_cpu(i) {
 124                 core_present = 0;
 125                 for_each_cpu(k, &temp_foreign_map)
 126                         if (cpus_are_siblings(i, k))
 127                                 core_present = 1;
 128                 if (!core_present)
 129                         cpumask_set_cpu(i, &temp_foreign_map);
 130         }
 131
 132         for_each_online_cpu(i)
 133                 cpumask_andnot(&cpu_foreign_map[i],
 134                                &temp_foreign_map, &cpu_sibling_map[i]);
 135 }
 136
 137 const struct plat_smp_ops *mp_ops;
 138 EXPORT_SYMBOL(mp_ops);
 139
 140 void register_smp_ops(const struct plat_smp_ops *ops)
 141 {
 142         if (mp_ops)
 143                 printk(KERN_WARNING "Overriding previously set SMP ops\n");
 144
 145         mp_ops = ops;
 146 }
 147
 148 #ifdef CONFIG_GENERIC_IRQ_IPI
 149 void mips_smp_send_ipi_single(int cpu, unsigned int action)
 150 {
 151         mips_smp_send_ipi_mask(cpumask_of(cpu), action);
 152 }
 153
 154 void mips_smp_send_ipi_mask(const struct cpumask *mask, unsigned int action)
 155 {
 156         unsigned long flags;
 157         unsigned int core;
 158         int cpu;
 159
 160         local_irq_save(flags);
 161
 162         switch (action) {
 163         case SMP_CALL_FUNCTION:
 164                 __ipi_send_mask(call_desc, mask);
 165                 break;
 166
 167         case SMP_RESCHEDULE_YOURSELF:
 168                 __ipi_send_mask(sched_desc, mask);
 169                 break;
 170
 171         default:
 172                 BUG();
 173         }
 174
 175         if (mips_cpc_present()) {
 176                 for_each_cpu(cpu, mask) {
 177                         if (cpus_are_siblings(cpu, smp_processor_id()))
 178                                 continue;
 179
 180                         core = cpu_core(&cpu_data[cpu]);
 181
 182                         while (!cpumask_test_cpu(cpu, &cpu_coherent_mask)) {
 183                                 mips_cm_lock_other_cpu(cpu, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 184                                 mips_cpc_lock_other(core);
 185                                 write_cpc_co_cmd(CPC_Cx_CMD_PWRUP);
 186                                 mips_cpc_unlock_other();
 187                                 mips_cm_unlock_other();
 188                         }
 189                 }
 190         }
 191
 192         local_irq_restore(flags);
 193 }
 194
 195
 196 static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id)
 197 {
 198         scheduler_ipi();
 199
 200         return IRQ_HANDLED;
 201 }
 202
 203 static irqreturn_t ipi_call_interrupt(int irq, void *dev_id)
 204 {
 205         generic_smp_call_function_interrupt();
 206
 207         return IRQ_HANDLED;
 208 }
 209
 210 static struct irqaction irq_resched = {
 211         .handler        = ipi_resched_interrupt,
 212         .flags          = IRQF_PERCPU,
 213         .name           = "IPI resched"
 214 };
 215
 216 static struct irqaction irq_call = {
 217         .handler        = ipi_call_interrupt,
 218         .flags          = IRQF_PERCPU,
 219         .name           = "IPI call"
 220 };
 221
 222 static void smp_ipi_init_one(unsigned int virq,
 223                                     struct irqaction *action)
 224 {
 225         int ret;
 226
 227         irq_set_handler(virq, handle_percpu_irq);
 228         ret = setup_irq(virq, action);
 229         BUG_ON(ret);
 230 }
 231
 232 static unsigned int call_virq, sched_virq;
 233
 234 int mips_smp_ipi_allocate(const struct cpumask *mask)
 235 {
 236         int virq;
 237         struct irq_domain *ipidomain;
 238         struct device_node *node;
 239
 240         node = of_irq_find_parent(of_root);
 241         ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);
 242
 243         /*
 244          * Some platforms have half DT setup. So if we found irq node but
 245          * didn't find an ipidomain, try to search for one that is not in the
 246          * DT.
 247          */
 248         if (node && !ipidomain)
 249                 ipidomain = irq_find_matching_host(NULL, DOMAIN_BUS_IPI);
 250
 251         /*
 252          * There are systems which use IPI IRQ domains, but only have one
 253          * registered when some runtime condition is met. For example a Malta
 254          * kernel may include support for GIC & CPU interrupt controller IPI
 255          * IRQ domains, but if run on a system with no GIC & no MT ASE then
 256          * neither will be supported or registered.
 257          *
 258          * We only have a problem if we're actually using multiple CPUs so fail
 259          * loudly if that is the case. Otherwise simply return, skipping IPI
 260          * setup, if we're running with only a single CPU.
 261          */
 262         if (!ipidomain) {
 263                 BUG_ON(num_present_cpus() > 1);
 264                 return 0;
 265         }
 266
 267         virq = irq_reserve_ipi(ipidomain, mask);
 268         BUG_ON(!virq);
 269         if (!call_virq)
 270                 call_virq = virq;
 271
 272         virq = irq_reserve_ipi(ipidomain, mask);
 273         BUG_ON(!virq);
 274         if (!sched_virq)
 275                 sched_virq = virq;
 276
 277         if (irq_domain_is_ipi_per_cpu(ipidomain)) {
 278                 int cpu;
 279
 280                 for_each_cpu(cpu, mask) {
 281                         smp_ipi_init_one(call_virq + cpu, &irq_call);
 282                         smp_ipi_init_one(sched_virq + cpu, &irq_resched);
 283                 }
 284         } else {
 285                 smp_ipi_init_one(call_virq, &irq_call);
 286                 smp_ipi_init_one(sched_virq, &irq_resched);
 287         }
 288
 289         return 0;
 290 }
 291
 292 int mips_smp_ipi_free(const struct cpumask *mask)
 293 {
 294         struct irq_domain *ipidomain;
 295         struct device_node *node;
 296
 297         node = of_irq_find_parent(of_root);
 298         ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);
 299
 300         /*
 301          * Some platforms have half DT setup. So if we found irq node but
 302          * didn't find an ipidomain, try to search for one that is not in the
 303          * DT.
 304          */
 305         if (node && !ipidomain)
 306                 ipidomain = irq_find_matching_host(NULL, DOMAIN_BUS_IPI);
 307
 308         BUG_ON(!ipidomain);
 309
 310         if (irq_domain_is_ipi_per_cpu(ipidomain)) {
 311                 int cpu;
 312
 313                 for_each_cpu(cpu, mask) {
 314                         remove_irq(call_virq + cpu, &irq_call);
 315                         remove_irq(sched_virq + cpu, &irq_resched);
 316                 }
 317         }
 318         irq_destroy_ipi(call_virq, mask);
 319         irq_destroy_ipi(sched_virq, mask);
 320         return 0;
 321 }
 322
 323
 324 static int __init mips_smp_ipi_init(void)
 325 {
 326         if (num_possible_cpus() == 1)
 327                 return 0;
 328
 329         mips_smp_ipi_allocate(cpu_possible_mask);
 330
 331         call_desc = irq_to_desc(call_virq);
 332         sched_desc = irq_to_desc(sched_virq);
 333
 334         return 0;
 335 }
 336 early_initcall(mips_smp_ipi_init);
 337 #endif
 338
 339 /*
 340  * First C code run on the secondary CPUs after being started up by
 341  * the master.
 342  */
 343 asmlinkage void start_secondary(void)
 344 {
 345         unsigned int cpu;
 346
 347         cpu_probe();
 348         per_cpu_trap_init(false);
 349         mips_clockevent_init();
 350         mp_ops->init_secondary();
 351         cpu_report();
 352         maar_init();
 353
 354         /*
 355          * XXX parity protection should be folded in here when it's converted
 356          * to an option instead of something based on .cputype
 357          */
 358
 359         calibrate_delay();
 360         preempt_disable();
 361         cpu = smp_processor_id();
 362         cpu_data[cpu].udelay_val = loops_per_jiffy;
 363
 364         cpumask_set_cpu(cpu, &cpu_coherent_mask);
 365         notify_cpu_starting(cpu);
 366
 367         /* Notify boot CPU that we're starting & ready to sync counters */
 368         complete(&cpu_starting);
 369
 370         synchronise_count_slave(cpu);
 371
 372         /* The CPU is running and counters synchronised, now mark it online */
 373         set_cpu_online(cpu, true);
 374
 375         set_cpu_sibling_map(cpu);
 376         set_cpu_core_map(cpu);
 377
 378         calculate_cpu_foreign_map();
 379
 380         /*
 381          * Notify boot CPU that we're up & online and it can safely return
 382          * from __cpu_up
 383          */
 384         complete(&cpu_running);
 385
 386         /*
 387          * irq will be enabled in ->smp_finish(), enabling it too early
 388          * is dangerous.
 389          */
 390         WARN_ON_ONCE(!irqs_disabled());
 391         mp_ops->smp_finish();
 392
 393         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 394 }
 395
 396 static void stop_this_cpu(void *dummy)
 397 {
 398         /*
 399          * Remove this CPU:
 400          */
 401
 402         set_cpu_online(smp_processor_id(), false);
 403         calculate_cpu_foreign_map();
 404         local_irq_disable();
 405         while (1);
 406 }
 407
 408 void smp_send_stop(void)
 409 {
 410         smp_call_function(stop_this_cpu, NULL, 0);
 411 }
 412
 413 void __init smp_cpus_done(unsigned int max_cpus)
 414 {
 415 }
 416
 417 /* called from main before smp_init() */
 418 void __init smp_prepare_cpus(unsigned int max_cpus)
 419 {
 420         init_new_context(current, &init_mm);
 421         current_thread_info()->cpu = 0;
 422         mp_ops->prepare_cpus(max_cpus);
 423         set_cpu_sibling_map(0);
 424         set_cpu_core_map(0);
 425         calculate_cpu_foreign_map();
 426 #ifndef CONFIG_HOTPLUG_CPU
 427         init_cpu_present(cpu_possible_mask);
 428 #endif
 429         cpumask_copy(&cpu_coherent_mask, cpu_possible_mask);
 430 }
 431
 432 /* preload SMP state for boot cpu */
 433 void smp_prepare_boot_cpu(void)
 434 {
 435         if (mp_ops->prepare_boot_cpu)
 436                 mp_ops->prepare_boot_cpu();
 437         set_cpu_possible(0, true);
 438         set_cpu_online(0, true);
 439 }
 440
 441 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 442 {
 443         int err;
 444
 445         err = mp_ops->boot_secondary(cpu, tidle);
 446         if (err)
 447                 return err;
 448
 449         /* Wait for CPU to start and be ready to sync counters */
 450         if (!wait_for_completion_timeout(&cpu_starting,
 451                                          msecs_to_jiffies(1000))) {
 452                 pr_crit("CPU%u: failed to start\n", cpu);
 453                 return -EIO;
 454         }
 455
 456         synchronise_count_master(cpu);
 457
 458         /* Wait for CPU to finish startup & mark itself online before return */
 459         wait_for_completion(&cpu_running);
 460         return 0;
 461 }
 462
 463 /* Not really SMP stuff ... */
 464 int setup_profiling_timer(unsigned int multiplier)
 465 {
 466         return 0;
 467 }
 468
 469 static void flush_tlb_all_ipi(void *info)
 470 {
 471         local_flush_tlb_all();
 472 }
 473
 474 void flush_tlb_all(void)
 475 {
 476         if (cpu_has_mmid) {
 477                 htw_stop();
 478                 ginvt_full();
 479                 sync_ginv();
 480                 instruction_hazard();
 481                 htw_start();
 482                 return;
 483         }
 484
 485         on_each_cpu(flush_tlb_all_ipi, NULL, 1);
 486 }
 487
 488 static void flush_tlb_mm_ipi(void *mm)
 489 {
 490         drop_mmu_context((struct mm_struct *)mm);
 491 }
 492
 493 /*
 494  * Special Variant of smp_call_function for use by TLB functions:
 495  *
 496  *  o No return value
 497  *  o collapses to normal function call on UP kernels
 498  *  o collapses to normal function call on systems with a single shared
 499  *    primary cache.
 500  */
 501 static inline void smp_on_other_tlbs(void (*func) (void *info), void *info)
 502 {
 503         smp_call_function(func, info, 1);
 504 }
 505
 506 static inline void smp_on_each_tlb(void (*func) (void *info), void *info)
 507 {
 508         preempt_disable();
 509
 510         smp_on_other_tlbs(func, info);
 511         func(info);
 512
 513         preempt_enable();
 514 }
 515
 516 /*
 517  * The following tlb flush calls are invoked when old translations are
 518  * being torn down, or pte attributes are changing. For single threaded
 519  * address spaces, a new context is obtained on the current cpu, and tlb
 520  * context on other cpus are invalidated to force a new context allocation
 521  * at switch_mm time, should the mm ever be used on other cpus. For
 522  * multithreaded address spaces, intercpu interrupts have to be sent.
 523  * Another case where intercpu interrupts are required is when the target
 524  * mm might be active on another cpu (eg debuggers doing the flushes on
 525  * behalf of debugees, kswapd stealing pages from another process etc).
 526  * Kanoj 07/00.
 527  */
 528
 529 void flush_tlb_mm(struct mm_struct *mm)
 530 {
 531         preempt_disable();
 532
 533         if (cpu_has_mmid) {
 534                 /*
 535                  * No need to worry about other CPUs - the ginvt in
 536                  * drop_mmu_context() will be globalized.
 537                  */
 538         } else if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
 539                 smp_on_other_tlbs(flush_tlb_mm_ipi, mm);
 540         } else {
 541                 unsigned int cpu;
 542
 543                 for_each_online_cpu(cpu) {
 544                         if (cpu != smp_processor_id() && cpu_context(cpu, mm))
 545                                 set_cpu_context(cpu, mm, 0);
 546                 }
 547         }
 548         drop_mmu_context(mm);
 549
 550         preempt_enable();
 551 }
 552
 553 struct flush_tlb_data {
 554         struct vm_area_struct *vma;
 555         unsigned long addr1;
 556         unsigned long addr2;
 557 };
 558
 559 static void flush_tlb_range_ipi(void *info)
 560 {
 561         struct flush_tlb_data *fd = info;
 562
 563         local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
 564 }
 565
 566 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 567 {
 568         struct mm_struct *mm = vma->vm_mm;
 569         unsigned long addr;
 570         u32 old_mmid;
 571
 572         preempt_disable();
 573         if (cpu_has_mmid) {
 574                 htw_stop();
 575                 old_mmid = read_c0_memorymapid();
 576                 write_c0_memorymapid(cpu_asid(0, mm));
 577                 mtc0_tlbw_hazard();
 578                 addr = round_down(start, PAGE_SIZE * 2);
 579                 end = round_up(end, PAGE_SIZE * 2);
 580                 do {
 581                         ginvt_va_mmid(addr);
 582                         sync_ginv();
 583                         addr += PAGE_SIZE * 2;
 584                 } while (addr < end);
 585                 write_c0_memorymapid(old_mmid);
 586                 instruction_hazard();
 587                 htw_start();
 588         } else if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
 589                 struct flush_tlb_data fd = {
 590                         .vma = vma,
 591                         .addr1 = start,
 592                         .addr2 = end,
 593                 };
 594
 595                 smp_on_other_tlbs(flush_tlb_range_ipi, &fd);
 596                 local_flush_tlb_range(vma, start, end);
 597         } else {
 598                 unsigned int cpu;
 599                 int exec = vma->vm_flags & VM_EXEC;
 600
 601                 for_each_online_cpu(cpu) {
 602                         /*
 603                          * flush_cache_range() will only fully flush icache if
 604                          * the VMA is executable, otherwise we must invalidate
 605                          * ASID without it appearing to has_valid_asid() as if
 606                          * mm has been completely unused by that CPU.
 607                          */
 608                         if (cpu != smp_processor_id() && cpu_context(cpu, mm))
 609                                 set_cpu_context(cpu, mm, !exec);
 610                 }
 611                 local_flush_tlb_range(vma, start, end);
 612         }
 613         preempt_enable();
 614 }
 615
 616 static void flush_tlb_kernel_range_ipi(void *info)
 617 {
 618         struct flush_tlb_data *fd = info;
 619
 620         local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
 621 }
 622
 623 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 624 {
 625         struct flush_tlb_data fd = {
 626                 .addr1 = start,
 627                 .addr2 = end,
 628         };
 629
 630         on_each_cpu(flush_tlb_kernel_range_ipi, &fd, 1);
 631 }
 632
 633 static void flush_tlb_page_ipi(void *info)
 634 {
 635         struct flush_tlb_data *fd = info;
 636
 637         local_flush_tlb_page(fd->vma, fd->addr1);
 638 }
 639
 640 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 641 {
 642         u32 old_mmid;
 643
 644         preempt_disable();
 645         if (cpu_has_mmid) {
 646                 htw_stop();
 647                 old_mmid = read_c0_memorymapid();
 648                 write_c0_memorymapid(cpu_asid(0, vma->vm_mm));
 649                 mtc0_tlbw_hazard();
 650                 ginvt_va_mmid(page);
 651                 sync_ginv();
 652                 write_c0_memorymapid(old_mmid);
 653                 instruction_hazard();
 654                 htw_start();
 655         } else if ((atomic_read(&vma->vm_mm->mm_users) != 1) ||
 656                    (current->mm != vma->vm_mm)) {
 657                 struct flush_tlb_data fd = {
 658                         .vma = vma,
 659                         .addr1 = page,
 660                 };
 661
 662                 smp_on_other_tlbs(flush_tlb_page_ipi, &fd);
 663                 local_flush_tlb_page(vma, page);
 664         } else {
 665                 unsigned int cpu;
 666
 667                 for_each_online_cpu(cpu) {
 668                         /*
 669                          * flush_cache_page() only does partial flushes, so
 670                          * invalidate ASID without it appearing to
 671                          * has_valid_asid() as if mm has been completely unused
 672                          * by that CPU.
 673                          */
 674                         if (cpu != smp_processor_id() && cpu_context(cpu, vma->vm_mm))
 675                                 set_cpu_context(cpu, vma->vm_mm, 1);
 676                 }
 677                 local_flush_tlb_page(vma, page);
 678         }
 679         preempt_enable();
 680 }
 681
 682 static void flush_tlb_one_ipi(void *info)
 683 {
 684         unsigned long vaddr = (unsigned long) info;
 685
 686         local_flush_tlb_one(vaddr);
 687 }
 688
 689 void flush_tlb_one(unsigned long vaddr)
 690 {
 691         smp_on_each_tlb(flush_tlb_one_ipi, (void *) vaddr);
 692 }
 693
 694 EXPORT_SYMBOL(flush_tlb_page);
 695 EXPORT_SYMBOL(flush_tlb_one);
 696
 697 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 698
 699 static DEFINE_PER_CPU(atomic_t, tick_broadcast_count);
 700 static DEFINE_PER_CPU(call_single_data_t, tick_broadcast_csd);
 701
 702 void tick_broadcast(const struct cpumask *mask)
 703 {
 704         atomic_t *count;
 705         call_single_data_t *csd;
 706         int cpu;
 707
 708         for_each_cpu(cpu, mask) {
 709                 count = &per_cpu(tick_broadcast_count, cpu);
 710                 csd = &per_cpu(tick_broadcast_csd, cpu);
 711
 712                 if (atomic_inc_return(count) == 1)
 713                         smp_call_function_single_async(cpu, csd);
 714         }
 715 }
 716
 717 static void tick_broadcast_callee(void *info)
 718 {
 719         int cpu = smp_processor_id();
 720         tick_receive_broadcast();
 721         atomic_set(&per_cpu(tick_broadcast_count, cpu), 0);
 722 }
 723
 724 static int __init tick_broadcast_init(void)
 725 {
 726         call_single_data_t *csd;
 727         int cpu;
 728
 729         for (cpu = 0; cpu < NR_CPUS; cpu++) {
 730                 csd = &per_cpu(tick_broadcast_csd, cpu);
 731                 csd->func = tick_broadcast_callee;
 732         }
 733
 734         return 0;
 735 }
 736 early_initcall(tick_broadcast_init);
 737
 738 #endif /* CONFIG_GENERIC_CLOCKEVENTS_BROADCAST */