arch/ia64/kernel/irq_ia64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/arch/ia64/kernel/irq_ia64.c
   4  *
   5  * Copyright (C) 1998-2001 Hewlett-Packard Co
   6  *      Stephane Eranian <eranian@hpl.hp.com>
   7  *      David Mosberger-Tang <davidm@hpl.hp.com>
   8  *
   9  *  6/10/99: Updated to bring in sync with x86 version to facilitate
  10  *           support for SMP and different interrupt controllers.
  11  *
  12  * 09/15/00 Goutham Rao <goutham.rao@intel.com> Implemented pci_irq_to_vector
  13  *                      PCI to vector allocation routine.
  14  * 04/14/2004 Ashok Raj <ashok.raj@intel.com>
  15  *                                              Added CPU Hotplug handling for IPF.
  16  */
  17
  18 #include <linux/module.h>
  19
  20 #include <linux/jiffies.h>
  21 #include <linux/errno.h>
  22 #include <linux/init.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/ioport.h>
  25 #include <linux/kernel_stat.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/signal.h>
  28 #include <linux/smp.h>
  29 #include <linux/threads.h>
  30 #include <linux/bitops.h>
  31 #include <linux/irq.h>
  32 #include <linux/ratelimit.h>
  33 #include <linux/acpi.h>
  34 #include <linux/sched.h>
  35
  36 #include <asm/delay.h>
  37 #include <asm/intrinsics.h>
  38 #include <asm/io.h>
  39 #include <asm/hw_irq.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/tlbflush.h>
  42
  43 #ifdef CONFIG_PERFMON
  44 # include <asm/perfmon.h>
  45 #endif
  46
  47 #define IRQ_DEBUG       0
  48
  49 #define IRQ_VECTOR_UNASSIGNED   (0)
  50
  51 #define IRQ_UNUSED              (0)
  52 #define IRQ_USED                (1)
  53 #define IRQ_RSVD                (2)
  54
  55 int ia64_first_device_vector = IA64_DEF_FIRST_DEVICE_VECTOR;
  56 int ia64_last_device_vector = IA64_DEF_LAST_DEVICE_VECTOR;
  57
  58 /* default base addr of IPI table */
  59 void __iomem *ipi_base_addr = ((void __iomem *)
  60                                (__IA64_UNCACHED_OFFSET | IA64_IPI_DEFAULT_BASE_ADDR));
  61
  62 static cpumask_t vector_allocation_domain(int cpu);
  63
  64 /*
  65  * Legacy IRQ to IA-64 vector translation table.
  66  */
  67 __u8 isa_irq_to_vector_map[16] = {
  68         /* 8259 IRQ translation, first 16 entries */
  69         0x2f, 0x20, 0x2e, 0x2d, 0x2c, 0x2b, 0x2a, 0x29,
  70         0x28, 0x27, 0x26, 0x25, 0x24, 0x23, 0x22, 0x21
  71 };
  72 EXPORT_SYMBOL(isa_irq_to_vector_map);
  73
  74 DEFINE_SPINLOCK(vector_lock);
  75
  76 struct irq_cfg irq_cfg[NR_IRQS] __read_mostly = {
  77         [0 ... NR_IRQS - 1] = {
  78                 .vector = IRQ_VECTOR_UNASSIGNED,
  79                 .domain = CPU_MASK_NONE
  80         }
  81 };
  82
  83 DEFINE_PER_CPU(int[IA64_NUM_VECTORS], vector_irq) = {
  84         [0 ... IA64_NUM_VECTORS - 1] = -1
  85 };
  86
  87 static cpumask_t vector_table[IA64_NUM_VECTORS] = {
  88         [0 ... IA64_NUM_VECTORS - 1] = CPU_MASK_NONE
  89 };
  90
  91 static int irq_status[NR_IRQS] = {
  92         [0 ... NR_IRQS -1] = IRQ_UNUSED
  93 };
  94
  95 static inline int find_unassigned_irq(void)
  96 {
  97         int irq;
  98
  99         for (irq = IA64_FIRST_DEVICE_VECTOR; irq < NR_IRQS; irq++)
 100                 if (irq_status[irq] == IRQ_UNUSED)
 101                         return irq;
 102         return -ENOSPC;
 103 }
 104
 105 static inline int find_unassigned_vector(cpumask_t domain)
 106 {
 107         cpumask_t mask;
 108         int pos, vector;
 109
 110         cpumask_and(&mask, &domain, cpu_online_mask);
 111         if (cpumask_empty(&mask))
 112                 return -EINVAL;
 113
 114         for (pos = 0; pos < IA64_NUM_DEVICE_VECTORS; pos++) {
 115                 vector = IA64_FIRST_DEVICE_VECTOR + pos;
 116                 cpumask_and(&mask, &domain, &vector_table[vector]);
 117                 if (!cpumask_empty(&mask))
 118                         continue;
 119                 return vector;
 120         }
 121         return -ENOSPC;
 122 }
 123
 124 static int __bind_irq_vector(int irq, int vector, cpumask_t domain)
 125 {
 126         cpumask_t mask;
 127         int cpu;
 128         struct irq_cfg *cfg = &irq_cfg[irq];
 129
 130         BUG_ON((unsigned)irq >= NR_IRQS);
 131         BUG_ON((unsigned)vector >= IA64_NUM_VECTORS);
 132
 133         cpumask_and(&mask, &domain, cpu_online_mask);
 134         if (cpumask_empty(&mask))
 135                 return -EINVAL;
 136         if ((cfg->vector == vector) && cpumask_equal(&cfg->domain, &domain))
 137                 return 0;
 138         if (cfg->vector != IRQ_VECTOR_UNASSIGNED)
 139                 return -EBUSY;
 140         for_each_cpu(cpu, &mask)
 141                 per_cpu(vector_irq, cpu)[vector] = irq;
 142         cfg->vector = vector;
 143         cfg->domain = domain;
 144         irq_status[irq] = IRQ_USED;
 145         cpumask_or(&vector_table[vector], &vector_table[vector], &domain);
 146         return 0;
 147 }
 148
 149 int bind_irq_vector(int irq, int vector, cpumask_t domain)
 150 {
 151         unsigned long flags;
 152         int ret;
 153
 154         spin_lock_irqsave(&vector_lock, flags);
 155         ret = __bind_irq_vector(irq, vector, domain);
 156         spin_unlock_irqrestore(&vector_lock, flags);
 157         return ret;
 158 }
 159
 160 static void __clear_irq_vector(int irq)
 161 {
 162         int vector, cpu;
 163         cpumask_t domain;
 164         struct irq_cfg *cfg = &irq_cfg[irq];
 165
 166         BUG_ON((unsigned)irq >= NR_IRQS);
 167         BUG_ON(cfg->vector == IRQ_VECTOR_UNASSIGNED);
 168         vector = cfg->vector;
 169         domain = cfg->domain;
 170         for_each_cpu_and(cpu, &cfg->domain, cpu_online_mask)
 171                 per_cpu(vector_irq, cpu)[vector] = -1;
 172         cfg->vector = IRQ_VECTOR_UNASSIGNED;
 173         cfg->domain = CPU_MASK_NONE;
 174         irq_status[irq] = IRQ_UNUSED;
 175         cpumask_andnot(&vector_table[vector], &vector_table[vector], &domain);
 176 }
 177
 178 static void clear_irq_vector(int irq)
 179 {
 180         unsigned long flags;
 181
 182         spin_lock_irqsave(&vector_lock, flags);
 183         __clear_irq_vector(irq);
 184         spin_unlock_irqrestore(&vector_lock, flags);
 185 }
 186
 187 int
 188 ia64_native_assign_irq_vector (int irq)
 189 {
 190         unsigned long flags;
 191         int vector, cpu;
 192         cpumask_t domain = CPU_MASK_NONE;
 193
 194         vector = -ENOSPC;
 195
 196         spin_lock_irqsave(&vector_lock, flags);
 197         for_each_online_cpu(cpu) {
 198                 domain = vector_allocation_domain(cpu);
 199                 vector = find_unassigned_vector(domain);
 200                 if (vector >= 0)
 201                         break;
 202         }
 203         if (vector < 0)
 204                 goto out;
 205         if (irq == AUTO_ASSIGN)
 206                 irq = vector;
 207         BUG_ON(__bind_irq_vector(irq, vector, domain));
 208  out:
 209         spin_unlock_irqrestore(&vector_lock, flags);
 210         return vector;
 211 }
 212
 213 void
 214 ia64_native_free_irq_vector (int vector)
 215 {
 216         if (vector < IA64_FIRST_DEVICE_VECTOR ||
 217             vector > IA64_LAST_DEVICE_VECTOR)
 218                 return;
 219         clear_irq_vector(vector);
 220 }
 221
 222 int
 223 reserve_irq_vector (int vector)
 224 {
 225         if (vector < IA64_FIRST_DEVICE_VECTOR ||
 226             vector > IA64_LAST_DEVICE_VECTOR)
 227                 return -EINVAL;
 228         return !!bind_irq_vector(vector, vector, CPU_MASK_ALL);
 229 }
 230
 231 /*
 232  * Initialize vector_irq on a new cpu. This function must be called
 233  * with vector_lock held.
 234  */
 235 void __setup_vector_irq(int cpu)
 236 {
 237         int irq, vector;
 238
 239         /* Clear vector_irq */
 240         for (vector = 0; vector < IA64_NUM_VECTORS; ++vector)
 241                 per_cpu(vector_irq, cpu)[vector] = -1;
 242         /* Mark the inuse vectors */
 243         for (irq = 0; irq < NR_IRQS; ++irq) {
 244                 if (!cpumask_test_cpu(cpu, &irq_cfg[irq].domain))
 245                         continue;
 246                 vector = irq_to_vector(irq);
 247                 per_cpu(vector_irq, cpu)[vector] = irq;
 248         }
 249 }
 250
 251 #ifdef CONFIG_SMP
 252
 253 static enum vector_domain_type {
 254         VECTOR_DOMAIN_NONE,
 255         VECTOR_DOMAIN_PERCPU
 256 } vector_domain_type = VECTOR_DOMAIN_NONE;
 257
 258 static cpumask_t vector_allocation_domain(int cpu)
 259 {
 260         if (vector_domain_type == VECTOR_DOMAIN_PERCPU)
 261                 return *cpumask_of(cpu);
 262         return CPU_MASK_ALL;
 263 }
 264
 265 static int __irq_prepare_move(int irq, int cpu)
 266 {
 267         struct irq_cfg *cfg = &irq_cfg[irq];
 268         int vector;
 269         cpumask_t domain;
 270
 271         if (cfg->move_in_progress || cfg->move_cleanup_count)
 272                 return -EBUSY;
 273         if (cfg->vector == IRQ_VECTOR_UNASSIGNED || !cpu_online(cpu))
 274                 return -EINVAL;
 275         if (cpumask_test_cpu(cpu, &cfg->domain))
 276                 return 0;
 277         domain = vector_allocation_domain(cpu);
 278         vector = find_unassigned_vector(domain);
 279         if (vector < 0)
 280                 return -ENOSPC;
 281         cfg->move_in_progress = 1;
 282         cfg->old_domain = cfg->domain;
 283         cfg->vector = IRQ_VECTOR_UNASSIGNED;
 284         cfg->domain = CPU_MASK_NONE;
 285         BUG_ON(__bind_irq_vector(irq, vector, domain));
 286         return 0;
 287 }
 288
 289 int irq_prepare_move(int irq, int cpu)
 290 {
 291         unsigned long flags;
 292         int ret;
 293
 294         spin_lock_irqsave(&vector_lock, flags);
 295         ret = __irq_prepare_move(irq, cpu);
 296         spin_unlock_irqrestore(&vector_lock, flags);
 297         return ret;
 298 }
 299
 300 void irq_complete_move(unsigned irq)
 301 {
 302         struct irq_cfg *cfg = &irq_cfg[irq];
 303         cpumask_t cleanup_mask;
 304         int i;
 305
 306         if (likely(!cfg->move_in_progress))
 307                 return;
 308
 309         if (unlikely(cpumask_test_cpu(smp_processor_id(), &cfg->old_domain)))
 310                 return;
 311
 312         cpumask_and(&cleanup_mask, &cfg->old_domain, cpu_online_mask);
 313         cfg->move_cleanup_count = cpumask_weight(&cleanup_mask);
 314         for_each_cpu(i, &cleanup_mask)
 315                 ia64_send_ipi(i, IA64_IRQ_MOVE_VECTOR, IA64_IPI_DM_INT, 0);
 316         cfg->move_in_progress = 0;
 317 }
 318
 319 static irqreturn_t smp_irq_move_cleanup_interrupt(int irq, void *dev_id)
 320 {
 321         int me = smp_processor_id();
 322         ia64_vector vector;
 323         unsigned long flags;
 324
 325         for (vector = IA64_FIRST_DEVICE_VECTOR;
 326              vector < IA64_LAST_DEVICE_VECTOR; vector++) {
 327                 int irq;
 328                 struct irq_desc *desc;
 329                 struct irq_cfg *cfg;
 330                 irq = __this_cpu_read(vector_irq[vector]);
 331                 if (irq < 0)
 332                         continue;
 333
 334                 desc = irq_to_desc(irq);
 335                 cfg = irq_cfg + irq;
 336                 raw_spin_lock(&desc->lock);
 337                 if (!cfg->move_cleanup_count)
 338                         goto unlock;
 339
 340                 if (!cpumask_test_cpu(me, &cfg->old_domain))
 341                         goto unlock;
 342
 343                 spin_lock_irqsave(&vector_lock, flags);
 344                 __this_cpu_write(vector_irq[vector], -1);
 345                 cpumask_clear_cpu(me, &vector_table[vector]);
 346                 spin_unlock_irqrestore(&vector_lock, flags);
 347                 cfg->move_cleanup_count--;
 348         unlock:
 349                 raw_spin_unlock(&desc->lock);
 350         }
 351         return IRQ_HANDLED;
 352 }
 353
 354 static struct irqaction irq_move_irqaction = {
 355         .handler =      smp_irq_move_cleanup_interrupt,
 356         .name =         "irq_move"
 357 };
 358
 359 static int __init parse_vector_domain(char *arg)
 360 {
 361         if (!arg)
 362                 return -EINVAL;
 363         if (!strcmp(arg, "percpu")) {
 364                 vector_domain_type = VECTOR_DOMAIN_PERCPU;
 365                 no_int_routing = 1;
 366         }
 367         return 0;
 368 }
 369 early_param("vector", parse_vector_domain);
 370 #else
 371 static cpumask_t vector_allocation_domain(int cpu)
 372 {
 373         return CPU_MASK_ALL;
 374 }
 375 #endif
 376
 377
 378 void destroy_and_reserve_irq(unsigned int irq)
 379 {
 380         unsigned long flags;
 381
 382         irq_init_desc(irq);
 383         spin_lock_irqsave(&vector_lock, flags);
 384         __clear_irq_vector(irq);
 385         irq_status[irq] = IRQ_RSVD;
 386         spin_unlock_irqrestore(&vector_lock, flags);
 387 }
 388
 389 /*
 390  * Dynamic irq allocate and deallocation for MSI
 391  */
 392 int create_irq(void)
 393 {
 394         unsigned long flags;
 395         int irq, vector, cpu;
 396         cpumask_t domain = CPU_MASK_NONE;
 397
 398         irq = vector = -ENOSPC;
 399         spin_lock_irqsave(&vector_lock, flags);
 400         for_each_online_cpu(cpu) {
 401                 domain = vector_allocation_domain(cpu);
 402                 vector = find_unassigned_vector(domain);
 403                 if (vector >= 0)
 404                         break;
 405         }
 406         if (vector < 0)
 407                 goto out;
 408         irq = find_unassigned_irq();
 409         if (irq < 0)
 410                 goto out;
 411         BUG_ON(__bind_irq_vector(irq, vector, domain));
 412  out:
 413         spin_unlock_irqrestore(&vector_lock, flags);
 414         if (irq >= 0)
 415                 irq_init_desc(irq);
 416         return irq;
 417 }
 418
 419 void destroy_irq(unsigned int irq)
 420 {
 421         irq_init_desc(irq);
 422         clear_irq_vector(irq);
 423 }
 424
 425 #ifdef CONFIG_SMP
 426 #       define IS_RESCHEDULE(vec)       (vec == IA64_IPI_RESCHEDULE)
 427 #       define IS_LOCAL_TLB_FLUSH(vec)  (vec == IA64_IPI_LOCAL_TLB_FLUSH)
 428 #else
 429 #       define IS_RESCHEDULE(vec)       (0)
 430 #       define IS_LOCAL_TLB_FLUSH(vec)  (0)
 431 #endif
 432 /*
 433  * That's where the IVT branches when we get an external
 434  * interrupt. This branches to the correct hardware IRQ handler via
 435  * function ptr.
 436  */
 437 void
 438 ia64_handle_irq (ia64_vector vector, struct pt_regs *regs)
 439 {
 440         struct pt_regs *old_regs = set_irq_regs(regs);
 441         unsigned long saved_tpr;
 442
 443 #if IRQ_DEBUG
 444         {
 445                 unsigned long bsp, sp;
 446
 447                 /*
 448                  * Note: if the interrupt happened while executing in
 449                  * the context switch routine (ia64_switch_to), we may
 450                  * get a spurious stack overflow here.  This is
 451                  * because the register and the memory stack are not
 452                  * switched atomically.
 453                  */
 454                 bsp = ia64_getreg(_IA64_REG_AR_BSP);
 455                 sp = ia64_getreg(_IA64_REG_SP);
 456
 457                 if ((sp - bsp) < 1024) {
 458                         static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
 459
 460                         if (__ratelimit(&ratelimit)) {
 461                                 printk("ia64_handle_irq: DANGER: less than "
 462                                        "1KB of free stack space!!\n"
 463                                        "(bsp=0x%lx, sp=%lx)\n", bsp, sp);
 464                         }
 465                 }
 466         }
 467 #endif /* IRQ_DEBUG */
 468
 469         /*
 470          * Always set TPR to limit maximum interrupt nesting depth to
 471          * 16 (without this, it would be ~240, which could easily lead
 472          * to kernel stack overflows).
 473          */
 474         irq_enter();
 475         saved_tpr = ia64_getreg(_IA64_REG_CR_TPR);
 476         ia64_srlz_d();
 477         while (vector != IA64_SPURIOUS_INT_VECTOR) {
 478                 int irq = local_vector_to_irq(vector);
 479
 480                 if (unlikely(IS_LOCAL_TLB_FLUSH(vector))) {
 481                         smp_local_flush_tlb();
 482                         kstat_incr_irq_this_cpu(irq);
 483                 } else if (unlikely(IS_RESCHEDULE(vector))) {
 484                         scheduler_ipi();
 485                         kstat_incr_irq_this_cpu(irq);
 486                 } else {
 487                         ia64_setreg(_IA64_REG_CR_TPR, vector);
 488                         ia64_srlz_d();
 489
 490                         if (unlikely(irq < 0)) {
 491                                 printk(KERN_ERR "%s: Unexpected interrupt "
 492                                        "vector %d on CPU %d is not mapped "
 493                                        "to any IRQ!\n", __func__, vector,
 494                                        smp_processor_id());
 495                         } else
 496                                 generic_handle_irq(irq);
 497
 498                         /*
 499                          * Disable interrupts and send EOI:
 500                          */
 501                         local_irq_disable();
 502                         ia64_setreg(_IA64_REG_CR_TPR, saved_tpr);
 503                 }
 504                 ia64_eoi();
 505                 vector = ia64_get_ivr();
 506         }
 507         /*
 508          * This must be done *after* the ia64_eoi().  For example, the keyboard softirq
 509          * handler needs to be able to wait for further keyboard interrupts, which can't
 510          * come through until ia64_eoi() has been done.
 511          */
 512         irq_exit();
 513         set_irq_regs(old_regs);
 514 }
 515
 516 #ifdef CONFIG_HOTPLUG_CPU
 517 /*
 518  * This function emulates a interrupt processing when a cpu is about to be
 519  * brought down.
 520  */
 521 void ia64_process_pending_intr(void)
 522 {
 523         ia64_vector vector;
 524         unsigned long saved_tpr;
 525         extern unsigned int vectors_in_migration[NR_IRQS];
 526
 527         vector = ia64_get_ivr();
 528
 529         irq_enter();
 530         saved_tpr = ia64_getreg(_IA64_REG_CR_TPR);
 531         ia64_srlz_d();
 532
 533          /*
 534           * Perform normal interrupt style processing
 535           */
 536         while (vector != IA64_SPURIOUS_INT_VECTOR) {
 537                 int irq = local_vector_to_irq(vector);
 538
 539                 if (unlikely(IS_LOCAL_TLB_FLUSH(vector))) {
 540                         smp_local_flush_tlb();
 541                         kstat_incr_irq_this_cpu(irq);
 542                 } else if (unlikely(IS_RESCHEDULE(vector))) {
 543                         kstat_incr_irq_this_cpu(irq);
 544                 } else {
 545                         struct pt_regs *old_regs = set_irq_regs(NULL);
 546
 547                         ia64_setreg(_IA64_REG_CR_TPR, vector);
 548                         ia64_srlz_d();
 549
 550                         /*
 551                          * Now try calling normal ia64_handle_irq as it would have got called
 552                          * from a real intr handler. Try passing null for pt_regs, hopefully
 553                          * it will work. I hope it works!.
 554                          * Probably could shared code.
 555                          */
 556                         if (unlikely(irq < 0)) {
 557                                 printk(KERN_ERR "%s: Unexpected interrupt "
 558                                        "vector %d on CPU %d not being mapped "
 559                                        "to any IRQ!!\n", __func__, vector,
 560                                        smp_processor_id());
 561                         } else {
 562                                 vectors_in_migration[irq]=0;
 563                                 generic_handle_irq(irq);
 564                         }
 565                         set_irq_regs(old_regs);
 566
 567                         /*
 568                          * Disable interrupts and send EOI
 569                          */
 570                         local_irq_disable();
 571                         ia64_setreg(_IA64_REG_CR_TPR, saved_tpr);
 572                 }
 573                 ia64_eoi();
 574                 vector = ia64_get_ivr();
 575         }
 576         irq_exit();
 577 }
 578 #endif
 579
 580
 581 #ifdef CONFIG_SMP
 582
 583 static irqreturn_t dummy_handler (int irq, void *dev_id)
 584 {
 585         BUG();
 586         return IRQ_NONE;
 587 }
 588
 589 static struct irqaction ipi_irqaction = {
 590         .handler =      handle_IPI,
 591         .name =         "IPI"
 592 };
 593
 594 /*
 595  * KVM uses this interrupt to force a cpu out of guest mode
 596  */
 597 static struct irqaction resched_irqaction = {
 598         .handler =      dummy_handler,
 599         .name =         "resched"
 600 };
 601
 602 static struct irqaction tlb_irqaction = {
 603         .handler =      dummy_handler,
 604         .name =         "tlb_flush"
 605 };
 606
 607 #endif
 608
 609 void
 610 ia64_native_register_percpu_irq (ia64_vector vec, struct irqaction *action)
 611 {
 612         unsigned int irq;
 613
 614         irq = vec;
 615         BUG_ON(bind_irq_vector(irq, vec, CPU_MASK_ALL));
 616         irq_set_status_flags(irq, IRQ_PER_CPU);
 617         irq_set_chip(irq, &irq_type_ia64_lsapic);
 618         if (action)
 619                 setup_irq(irq, action);
 620         irq_set_handler(irq, handle_percpu_irq);
 621 }
 622
 623 void __init
 624 ia64_native_register_ipi(void)
 625 {
 626 #ifdef CONFIG_SMP
 627         register_percpu_irq(IA64_IPI_VECTOR, &ipi_irqaction);
 628         register_percpu_irq(IA64_IPI_RESCHEDULE, &resched_irqaction);
 629         register_percpu_irq(IA64_IPI_LOCAL_TLB_FLUSH, &tlb_irqaction);
 630 #endif
 631 }
 632
 633 void __init
 634 init_IRQ (void)
 635 {
 636         acpi_boot_init();
 637         ia64_register_ipi();
 638         register_percpu_irq(IA64_SPURIOUS_INT_VECTOR, NULL);
 639 #ifdef CONFIG_SMP
 640         if (vector_domain_type != VECTOR_DOMAIN_NONE)
 641                 register_percpu_irq(IA64_IRQ_MOVE_VECTOR, &irq_move_irqaction);
 642 #endif
 643 #ifdef CONFIG_PERFMON
 644         pfm_init_percpu();
 645 #endif
 646 }
 647
 648 void
 649 ia64_send_ipi (int cpu, int vector, int delivery_mode, int redirect)
 650 {
 651         void __iomem *ipi_addr;
 652         unsigned long ipi_data;
 653         unsigned long phys_cpu_id;
 654
 655         phys_cpu_id = cpu_physical_id(cpu);
 656
 657         /*
 658          * cpu number is in 8bit ID and 8bit EID
 659          */
 660
 661         ipi_data = (delivery_mode << 8) | (vector & 0xff);
 662         ipi_addr = ipi_base_addr + ((phys_cpu_id << 4) | ((redirect & 1) << 3));
 663
 664         writeq(ipi_data, ipi_addr);
 665 }