drivers/xen/events.c

   1 /*
   2  * Xen event channels
   3  *
   4  * Xen models interrupts with abstract event channels.  Because each
   5  * domain gets 1024 event channels, but NR_IRQ is not that large, we
   6  * must dynamically map irqs<->event channels.  The event channels
   7  * interface with the rest of the kernel by defining a xen interrupt
   8  * chip.  When an event is recieved, it is mapped to an irq and sent
   9  * through the normal interrupt processing path.
  10  *
  11  * There are four kinds of events which can be mapped to an event
  12  * channel:
  13  *
  14  * 1. Inter-domain notifications.  This includes all the virtual
  15  *    device events, since they're driven by front-ends in another domain
  16  *    (typically dom0).
  17  * 2. VIRQs, typically used for timers.  These are per-cpu events.
  18  * 3. IPIs.
  19  * 4. Hardware interrupts. Not supported at present.
  20  *
  21  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  22  */
  23
  24 #include <linux/linkage.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/irq.h>
  27 #include <linux/module.h>
  28 #include <linux/string.h>
  29 #include <linux/bootmem.h>
  30 #include <linux/slab.h>
  31
  32 #include <asm/ptrace.h>
  33 #include <asm/irq.h>
  34 #include <asm/idle.h>
  35 #include <asm/sync_bitops.h>
  36 #include <asm/xen/hypercall.h>
  37 #include <asm/xen/hypervisor.h>
  38
  39 #include <xen/xen-ops.h>
  40 #include <xen/events.h>
  41 #include <xen/interface/xen.h>
  42 #include <xen/interface/event_channel.h>
  43
  44 /*
  45  * This lock protects updates to the following mapping and reference-count
  46  * arrays. The lock does not need to be acquired to read the mapping tables.
  47  */
  48 static DEFINE_SPINLOCK(irq_mapping_update_lock);
  49
  50 /* IRQ <-> VIRQ mapping. */
  51 static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
  52
  53 /* IRQ <-> IPI mapping */
  54 static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
  55
  56 /* Interrupt types. */
  57 enum xen_irq_type {
  58         IRQT_UNBOUND = 0,
  59         IRQT_PIRQ,
  60         IRQT_VIRQ,
  61         IRQT_IPI,
  62         IRQT_EVTCHN
  63 };
  64
  65 /*
  66  * Packed IRQ information:
  67  * type - enum xen_irq_type
  68  * event channel - irq->event channel mapping
  69  * cpu - cpu this event channel is bound to
  70  * index - type-specific information:
  71  *    PIRQ - vector, with MSB being "needs EIO"
  72  *    VIRQ - virq number
  73  *    IPI - IPI vector
  74  *    EVTCHN -
  75  */
  76 struct irq_info
  77 {
  78         enum xen_irq_type type; /* type */
  79         unsigned short evtchn;  /* event channel */
  80         unsigned short cpu;     /* cpu bound */
  81
  82         union {
  83                 unsigned short virq;
  84                 enum ipi_vector ipi;
  85                 struct {
  86                         unsigned short gsi;
  87                         unsigned short vector;
  88                 } pirq;
  89         } u;
  90 };
  91
  92 static struct irq_info irq_info[NR_IRQS];
  93
  94 static int evtchn_to_irq[NR_EVENT_CHANNELS] = {
  95         [0 ... NR_EVENT_CHANNELS-1] = -1
  96 };
  97 struct cpu_evtchn_s {
  98         unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
  99 };
 100 static struct cpu_evtchn_s *cpu_evtchn_mask_p;
 101 static inline unsigned long *cpu_evtchn_mask(int cpu)
 102 {
 103         return cpu_evtchn_mask_p[cpu].bits;
 104 }
 105
 106 /* Xen will never allocate port zero for any purpose. */
 107 #define VALID_EVTCHN(chn)       ((chn) != 0)
 108
 109 static struct irq_chip xen_dynamic_chip;
 110 static struct irq_chip xen_percpu_chip;
 111
 112 /* Constructor for packed IRQ information. */
 113 static struct irq_info mk_unbound_info(void)
 114 {
 115         return (struct irq_info) { .type = IRQT_UNBOUND };
 116 }
 117
 118 static struct irq_info mk_evtchn_info(unsigned short evtchn)
 119 {
 120         return (struct irq_info) { .type = IRQT_EVTCHN, .evtchn = evtchn,
 121                         .cpu = 0 };
 122 }
 123
 124 static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi)
 125 {
 126         return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn,
 127                         .cpu = 0, .u.ipi = ipi };
 128 }
 129
 130 static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq)
 131 {
 132         return (struct irq_info) { .type = IRQT_VIRQ, .evtchn = evtchn,
 133                         .cpu = 0, .u.virq = virq };
 134 }
 135
 136 static struct irq_info mk_pirq_info(unsigned short evtchn,
 137                                     unsigned short gsi, unsigned short vector)
 138 {
 139         return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
 140                         .cpu = 0, .u.pirq = { .gsi = gsi, .vector = vector } };
 141 }
 142
 143 /*
 144  * Accessors for packed IRQ information.
 145  */
 146 static struct irq_info *info_for_irq(unsigned irq)
 147 {
 148         return &irq_info[irq];
 149 }
 150
 151 static unsigned int evtchn_from_irq(unsigned irq)
 152 {
 153         return info_for_irq(irq)->evtchn;
 154 }
 155
 156 unsigned irq_from_evtchn(unsigned int evtchn)
 157 {
 158         return evtchn_to_irq[evtchn];
 159 }
 160 EXPORT_SYMBOL_GPL(irq_from_evtchn);
 161
 162 static enum ipi_vector ipi_from_irq(unsigned irq)
 163 {
 164         struct irq_info *info = info_for_irq(irq);
 165
 166         BUG_ON(info == NULL);
 167         BUG_ON(info->type != IRQT_IPI);
 168
 169         return info->u.ipi;
 170 }
 171
 172 static unsigned virq_from_irq(unsigned irq)
 173 {
 174         struct irq_info *info = info_for_irq(irq);
 175
 176         BUG_ON(info == NULL);
 177         BUG_ON(info->type != IRQT_VIRQ);
 178
 179         return info->u.virq;
 180 }
 181
 182 static unsigned gsi_from_irq(unsigned irq)
 183 {
 184         struct irq_info *info = info_for_irq(irq);
 185
 186         BUG_ON(info == NULL);
 187         BUG_ON(info->type != IRQT_PIRQ);
 188
 189         return info->u.pirq.gsi;
 190 }
 191
 192 static unsigned vector_from_irq(unsigned irq)
 193 {
 194         struct irq_info *info = info_for_irq(irq);
 195
 196         BUG_ON(info == NULL);
 197         BUG_ON(info->type != IRQT_PIRQ);
 198
 199         return info->u.pirq.vector;
 200 }
 201
 202 static enum xen_irq_type type_from_irq(unsigned irq)
 203 {
 204         return info_for_irq(irq)->type;
 205 }
 206
 207 static unsigned cpu_from_irq(unsigned irq)
 208 {
 209         return info_for_irq(irq)->cpu;
 210 }
 211
 212 static unsigned int cpu_from_evtchn(unsigned int evtchn)
 213 {
 214         int irq = evtchn_to_irq[evtchn];
 215         unsigned ret = 0;
 216
 217         if (irq != -1)
 218                 ret = cpu_from_irq(irq);
 219
 220         return ret;
 221 }
 222
 223 static inline unsigned long active_evtchns(unsigned int cpu,
 224                                            struct shared_info *sh,
 225                                            unsigned int idx)
 226 {
 227         return (sh->evtchn_pending[idx] &
 228                 cpu_evtchn_mask(cpu)[idx] &
 229                 ~sh->evtchn_mask[idx]);
 230 }
 231
 232 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 233 {
 234         int irq = evtchn_to_irq[chn];
 235
 236         BUG_ON(irq == -1);
 237 #ifdef CONFIG_SMP
 238         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 239 #endif
 240
 241         __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
 242         __set_bit(chn, cpu_evtchn_mask(cpu));
 243
 244         irq_info[irq].cpu = cpu;
 245 }
 246
 247 static void init_evtchn_cpu_bindings(void)
 248 {
 249 #ifdef CONFIG_SMP
 250         struct irq_desc *desc;
 251         int i;
 252
 253         /* By default all event channels notify CPU#0. */
 254         for_each_irq_desc(i, desc) {
 255                 cpumask_copy(desc->affinity, cpumask_of(0));
 256         }
 257 #endif
 258
 259         memset(cpu_evtchn_mask(0), ~0, sizeof(struct cpu_evtchn_s));
 260 }
 261
 262 static inline void clear_evtchn(int port)
 263 {
 264         struct shared_info *s = HYPERVISOR_shared_info;
 265         sync_clear_bit(port, &s->evtchn_pending[0]);
 266 }
 267
 268 static inline void set_evtchn(int port)
 269 {
 270         struct shared_info *s = HYPERVISOR_shared_info;
 271         sync_set_bit(port, &s->evtchn_pending[0]);
 272 }
 273
 274 static inline int test_evtchn(int port)
 275 {
 276         struct shared_info *s = HYPERVISOR_shared_info;
 277         return sync_test_bit(port, &s->evtchn_pending[0]);
 278 }
 279
 280
 281 /**
 282  * notify_remote_via_irq - send event to remote end of event channel via irq
 283  * @irq: irq of event channel to send event to
 284  *
 285  * Unlike notify_remote_via_evtchn(), this is safe to use across
 286  * save/restore. Notifications on a broken connection are silently
 287  * dropped.
 288  */
 289 void notify_remote_via_irq(int irq)
 290 {
 291         int evtchn = evtchn_from_irq(irq);
 292
 293         if (VALID_EVTCHN(evtchn))
 294                 notify_remote_via_evtchn(evtchn);
 295 }
 296 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 297
 298 static void mask_evtchn(int port)
 299 {
 300         struct shared_info *s = HYPERVISOR_shared_info;
 301         sync_set_bit(port, &s->evtchn_mask[0]);
 302 }
 303
 304 static void unmask_evtchn(int port)
 305 {
 306         struct shared_info *s = HYPERVISOR_shared_info;
 307         unsigned int cpu = get_cpu();
 308
 309         BUG_ON(!irqs_disabled());
 310
 311         /* Slow path (hypercall) if this is a non-local port. */
 312         if (unlikely(cpu != cpu_from_evtchn(port))) {
 313                 struct evtchn_unmask unmask = { .port = port };
 314                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 315         } else {
 316                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 317
 318                 sync_clear_bit(port, &s->evtchn_mask[0]);
 319
 320                 /*
 321                  * The following is basically the equivalent of
 322                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 323                  * the interrupt edge' if the channel is masked.
 324                  */
 325                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 326                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 327                                            &vcpu_info->evtchn_pending_sel))
 328                         vcpu_info->evtchn_upcall_pending = 1;
 329         }
 330
 331         put_cpu();
 332 }
 333
 334 static int find_unbound_irq(void)
 335 {
 336         int irq;
 337         struct irq_desc *desc;
 338
 339         for (irq = 0; irq < nr_irqs; irq++)
 340                 if (irq_info[irq].type == IRQT_UNBOUND)
 341                         break;
 342
 343         if (irq == nr_irqs)
 344                 panic("No available IRQ to bind to: increase nr_irqs!\n");
 345
 346         desc = irq_to_desc_alloc_node(irq, 0);
 347         if (WARN_ON(desc == NULL))
 348                 return -1;
 349
 350         dynamic_irq_init(irq);
 351
 352         return irq;
 353 }
 354
 355 int bind_evtchn_to_irq(unsigned int evtchn)
 356 {
 357         int irq;
 358
 359         spin_lock(&irq_mapping_update_lock);
 360
 361         irq = evtchn_to_irq[evtchn];
 362
 363         if (irq == -1) {
 364                 irq = find_unbound_irq();
 365
 366                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 367                                               handle_edge_irq, "event");
 368
 369                 evtchn_to_irq[evtchn] = irq;
 370                 irq_info[irq] = mk_evtchn_info(evtchn);
 371         }
 372
 373         spin_unlock(&irq_mapping_update_lock);
 374
 375         return irq;
 376 }
 377 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 378
 379 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 380 {
 381         struct evtchn_bind_ipi bind_ipi;
 382         int evtchn, irq;
 383
 384         spin_lock(&irq_mapping_update_lock);
 385
 386         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 387
 388         if (irq == -1) {
 389                 irq = find_unbound_irq();
 390                 if (irq < 0)
 391                         goto out;
 392
 393                 set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 394                                               handle_percpu_irq, "ipi");
 395
 396                 bind_ipi.vcpu = cpu;
 397                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 398                                                 &bind_ipi) != 0)
 399                         BUG();
 400                 evtchn = bind_ipi.port;
 401
 402                 evtchn_to_irq[evtchn] = irq;
 403                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 404                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 405
 406                 bind_evtchn_to_cpu(evtchn, cpu);
 407         }
 408
 409  out:
 410         spin_unlock(&irq_mapping_update_lock);
 411         return irq;
 412 }
 413
 414
 415 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 416 {
 417         struct evtchn_bind_virq bind_virq;
 418         int evtchn, irq;
 419
 420         spin_lock(&irq_mapping_update_lock);
 421
 422         irq = per_cpu(virq_to_irq, cpu)[virq];
 423
 424         if (irq == -1) {
 425                 bind_virq.virq = virq;
 426                 bind_virq.vcpu = cpu;
 427                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 428                                                 &bind_virq) != 0)
 429                         BUG();
 430                 evtchn = bind_virq.port;
 431
 432                 irq = find_unbound_irq();
 433
 434                 set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 435                                               handle_percpu_irq, "virq");
 436
 437                 evtchn_to_irq[evtchn] = irq;
 438                 irq_info[irq] = mk_virq_info(evtchn, virq);
 439
 440                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 441
 442                 bind_evtchn_to_cpu(evtchn, cpu);
 443         }
 444
 445         spin_unlock(&irq_mapping_update_lock);
 446
 447         return irq;
 448 }
 449
 450 static void unbind_from_irq(unsigned int irq)
 451 {
 452         struct evtchn_close close;
 453         int evtchn = evtchn_from_irq(irq);
 454
 455         spin_lock(&irq_mapping_update_lock);
 456
 457         if (VALID_EVTCHN(evtchn)) {
 458                 close.port = evtchn;
 459                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 460                         BUG();
 461
 462                 switch (type_from_irq(irq)) {
 463                 case IRQT_VIRQ:
 464                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 465                                 [virq_from_irq(irq)] = -1;
 466                         break;
 467                 case IRQT_IPI:
 468                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 469                                 [ipi_from_irq(irq)] = -1;
 470                         break;
 471                 default:
 472                         break;
 473                 }
 474
 475                 /* Closed ports are implicitly re-bound to VCPU0. */
 476                 bind_evtchn_to_cpu(evtchn, 0);
 477
 478                 evtchn_to_irq[evtchn] = -1;
 479         }
 480
 481         if (irq_info[irq].type != IRQT_UNBOUND) {
 482                 irq_info[irq] = mk_unbound_info();
 483
 484                 dynamic_irq_cleanup(irq);
 485         }
 486
 487         spin_unlock(&irq_mapping_update_lock);
 488 }
 489
 490 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 491                               irq_handler_t handler,
 492                               unsigned long irqflags,
 493                               const char *devname, void *dev_id)
 494 {
 495         unsigned int irq;
 496         int retval;
 497
 498         irq = bind_evtchn_to_irq(evtchn);
 499         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 500         if (retval != 0) {
 501                 unbind_from_irq(irq);
 502                 return retval;
 503         }
 504
 505         return irq;
 506 }
 507 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 508
 509 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 510                             irq_handler_t handler,
 511                             unsigned long irqflags, const char *devname, void *dev_id)
 512 {
 513         unsigned int irq;
 514         int retval;
 515
 516         irq = bind_virq_to_irq(virq, cpu);
 517         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 518         if (retval != 0) {
 519                 unbind_from_irq(irq);
 520                 return retval;
 521         }
 522
 523         return irq;
 524 }
 525 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 526
 527 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 528                            unsigned int cpu,
 529                            irq_handler_t handler,
 530                            unsigned long irqflags,
 531                            const char *devname,
 532                            void *dev_id)
 533 {
 534         int irq, retval;
 535
 536         irq = bind_ipi_to_irq(ipi, cpu);
 537         if (irq < 0)
 538                 return irq;
 539
 540         irqflags |= IRQF_NO_SUSPEND;
 541         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 542         if (retval != 0) {
 543                 unbind_from_irq(irq);
 544                 return retval;
 545         }
 546
 547         return irq;
 548 }
 549
 550 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 551 {
 552         free_irq(irq, dev_id);
 553         unbind_from_irq(irq);
 554 }
 555 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 556
 557 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 558 {
 559         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 560         BUG_ON(irq < 0);
 561         notify_remote_via_irq(irq);
 562 }
 563
 564 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 565 {
 566         struct shared_info *sh = HYPERVISOR_shared_info;
 567         int cpu = smp_processor_id();
 568         int i;
 569         unsigned long flags;
 570         static DEFINE_SPINLOCK(debug_lock);
 571
 572         spin_lock_irqsave(&debug_lock, flags);
 573
 574         printk("vcpu %d\n  ", cpu);
 575
 576         for_each_online_cpu(i) {
 577                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 578                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 579                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 580                         v->evtchn_upcall_pending,
 581                         v->evtchn_pending_sel);
 582         }
 583         printk("pending:\n   ");
 584         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 585                 printk("%08lx%s", sh->evtchn_pending[i],
 586                         i % 8 == 0 ? "\n   " : " ");
 587         printk("\nmasks:\n   ");
 588         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 589                 printk("%08lx%s", sh->evtchn_mask[i],
 590                         i % 8 == 0 ? "\n   " : " ");
 591
 592         printk("\nunmasked:\n   ");
 593         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 594                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 595                         i % 8 == 0 ? "\n   " : " ");
 596
 597         printk("\npending list:\n");
 598         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 599                 if (sync_test_bit(i, sh->evtchn_pending)) {
 600                         printk("  %d: event %d -> irq %d\n",
 601                                cpu_from_evtchn(i), i,
 602                                evtchn_to_irq[i]);
 603                 }
 604         }
 605
 606         spin_unlock_irqrestore(&debug_lock, flags);
 607
 608         return IRQ_HANDLED;
 609 }
 610
 611 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
 612
 613 /*
 614  * Search the CPUs pending events bitmasks.  For each one found, map
 615  * the event number to an irq, and feed it into do_IRQ() for
 616  * handling.
 617  *
 618  * Xen uses a two-level bitmap to speed searching.  The first level is
 619  * a bitset of words which contain pending event bits.  The second
 620  * level is a bitset of pending events themselves.
 621  */
 622 void xen_evtchn_do_upcall(struct pt_regs *regs)
 623 {
 624         int cpu = get_cpu();
 625         struct pt_regs *old_regs = set_irq_regs(regs);
 626         struct shared_info *s = HYPERVISOR_shared_info;
 627         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 628         unsigned count;
 629
 630         exit_idle();
 631         irq_enter();
 632
 633         do {
 634                 unsigned long pending_words;
 635
 636                 vcpu_info->evtchn_upcall_pending = 0;
 637
 638                 if (__get_cpu_var(xed_nesting_count)++)
 639                         goto out;
 640
 641 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 642                 /* Clear master flag /before/ clearing selector flag. */
 643                 wmb();
 644 #endif
 645                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 646                 while (pending_words != 0) {
 647                         unsigned long pending_bits;
 648                         int word_idx = __ffs(pending_words);
 649                         pending_words &= ~(1UL << word_idx);
 650
 651                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 652                                 int bit_idx = __ffs(pending_bits);
 653                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 654                                 int irq = evtchn_to_irq[port];
 655                                 struct irq_desc *desc;
 656
 657                                 if (irq != -1) {
 658                                         desc = irq_to_desc(irq);
 659                                         if (desc)
 660                                                 generic_handle_irq_desc(irq, desc);
 661                                 }
 662                         }
 663                 }
 664
 665                 BUG_ON(!irqs_disabled());
 666
 667                 count = __get_cpu_var(xed_nesting_count);
 668                 __get_cpu_var(xed_nesting_count) = 0;
 669         } while(count != 1);
 670
 671 out:
 672         irq_exit();
 673         set_irq_regs(old_regs);
 674
 675         put_cpu();
 676 }
 677
 678 /* Rebind a new event channel to an existing irq. */
 679 void rebind_evtchn_irq(int evtchn, int irq)
 680 {
 681         struct irq_info *info = info_for_irq(irq);
 682
 683         /* Make sure the irq is masked, since the new event channel
 684            will also be masked. */
 685         disable_irq(irq);
 686
 687         spin_lock(&irq_mapping_update_lock);
 688
 689         /* After resume the irq<->evtchn mappings are all cleared out */
 690         BUG_ON(evtchn_to_irq[evtchn] != -1);
 691         /* Expect irq to have been bound before,
 692            so there should be a proper type */
 693         BUG_ON(info->type == IRQT_UNBOUND);
 694
 695         evtchn_to_irq[evtchn] = irq;
 696         irq_info[irq] = mk_evtchn_info(evtchn);
 697
 698         spin_unlock(&irq_mapping_update_lock);
 699
 700         /* new event channels are always bound to cpu 0 */
 701         irq_set_affinity(irq, cpumask_of(0));
 702
 703         /* Unmask the event channel. */
 704         enable_irq(irq);
 705 }
 706
 707 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 708 static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 709 {
 710         struct evtchn_bind_vcpu bind_vcpu;
 711         int evtchn = evtchn_from_irq(irq);
 712
 713         if (!VALID_EVTCHN(evtchn))
 714                 return -1;
 715
 716         /* Send future instances of this interrupt to other vcpu. */
 717         bind_vcpu.port = evtchn;
 718         bind_vcpu.vcpu = tcpu;
 719
 720         /*
 721          * If this fails, it usually just indicates that we're dealing with a
 722          * virq or IPI channel, which don't actually need to be rebound. Ignore
 723          * it, but don't do the xenlinux-level rebind in that case.
 724          */
 725         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 726                 bind_evtchn_to_cpu(evtchn, tcpu);
 727
 728         return 0;
 729 }
 730
 731 static int set_affinity_irq(unsigned irq, const struct cpumask *dest)
 732 {
 733         unsigned tcpu = cpumask_first(dest);
 734
 735         return rebind_irq_to_cpu(irq, tcpu);
 736 }
 737
 738 int resend_irq_on_evtchn(unsigned int irq)
 739 {
 740         int masked, evtchn = evtchn_from_irq(irq);
 741         struct shared_info *s = HYPERVISOR_shared_info;
 742
 743         if (!VALID_EVTCHN(evtchn))
 744                 return 1;
 745
 746         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
 747         sync_set_bit(evtchn, s->evtchn_pending);
 748         if (!masked)
 749                 unmask_evtchn(evtchn);
 750
 751         return 1;
 752 }
 753
 754 static void enable_dynirq(unsigned int irq)
 755 {
 756         int evtchn = evtchn_from_irq(irq);
 757
 758         if (VALID_EVTCHN(evtchn))
 759                 unmask_evtchn(evtchn);
 760 }
 761
 762 static void disable_dynirq(unsigned int irq)
 763 {
 764         int evtchn = evtchn_from_irq(irq);
 765
 766         if (VALID_EVTCHN(evtchn))
 767                 mask_evtchn(evtchn);
 768 }
 769
 770 static void ack_dynirq(unsigned int irq)
 771 {
 772         int evtchn = evtchn_from_irq(irq);
 773
 774         move_native_irq(irq);
 775
 776         if (VALID_EVTCHN(evtchn))
 777                 clear_evtchn(evtchn);
 778 }
 779
 780 static int retrigger_dynirq(unsigned int irq)
 781 {
 782         int evtchn = evtchn_from_irq(irq);
 783         struct shared_info *sh = HYPERVISOR_shared_info;
 784         int ret = 0;
 785
 786         if (VALID_EVTCHN(evtchn)) {
 787                 int masked;
 788
 789                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
 790                 sync_set_bit(evtchn, sh->evtchn_pending);
 791                 if (!masked)
 792                         unmask_evtchn(evtchn);
 793                 ret = 1;
 794         }
 795
 796         return ret;
 797 }
 798
 799 static void restore_cpu_virqs(unsigned int cpu)
 800 {
 801         struct evtchn_bind_virq bind_virq;
 802         int virq, irq, evtchn;
 803
 804         for (virq = 0; virq < NR_VIRQS; virq++) {
 805                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
 806                         continue;
 807
 808                 BUG_ON(virq_from_irq(irq) != virq);
 809
 810                 /* Get a new binding from Xen. */
 811                 bind_virq.virq = virq;
 812                 bind_virq.vcpu = cpu;
 813                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 814                                                 &bind_virq) != 0)
 815                         BUG();
 816                 evtchn = bind_virq.port;
 817
 818                 /* Record the new mapping. */
 819                 evtchn_to_irq[evtchn] = irq;
 820                 irq_info[irq] = mk_virq_info(evtchn, virq);
 821                 bind_evtchn_to_cpu(evtchn, cpu);
 822
 823                 /* Ready for use. */
 824                 unmask_evtchn(evtchn);
 825         }
 826 }
 827
 828 static void restore_cpu_ipis(unsigned int cpu)
 829 {
 830         struct evtchn_bind_ipi bind_ipi;
 831         int ipi, irq, evtchn;
 832
 833         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
 834                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
 835                         continue;
 836
 837                 BUG_ON(ipi_from_irq(irq) != ipi);
 838
 839                 /* Get a new binding from Xen. */
 840                 bind_ipi.vcpu = cpu;
 841                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 842                                                 &bind_ipi) != 0)
 843                         BUG();
 844                 evtchn = bind_ipi.port;
 845
 846                 /* Record the new mapping. */
 847                 evtchn_to_irq[evtchn] = irq;
 848                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 849                 bind_evtchn_to_cpu(evtchn, cpu);
 850
 851                 /* Ready for use. */
 852                 unmask_evtchn(evtchn);
 853
 854         }
 855 }
 856
 857 /* Clear an irq's pending state, in preparation for polling on it */
 858 void xen_clear_irq_pending(int irq)
 859 {
 860         int evtchn = evtchn_from_irq(irq);
 861
 862         if (VALID_EVTCHN(evtchn))
 863                 clear_evtchn(evtchn);
 864 }
 865
 866 void xen_set_irq_pending(int irq)
 867 {
 868         int evtchn = evtchn_from_irq(irq);
 869
 870         if (VALID_EVTCHN(evtchn))
 871                 set_evtchn(evtchn);
 872 }
 873
 874 bool xen_test_irq_pending(int irq)
 875 {
 876         int evtchn = evtchn_from_irq(irq);
 877         bool ret = false;
 878
 879         if (VALID_EVTCHN(evtchn))
 880                 ret = test_evtchn(evtchn);
 881
 882         return ret;
 883 }
 884
 885 /* Poll waiting for an irq to become pending.  In the usual case, the
 886    irq will be disabled so it won't deliver an interrupt. */
 887 void xen_poll_irq(int irq)
 888 {
 889         evtchn_port_t evtchn = evtchn_from_irq(irq);
 890
 891         if (VALID_EVTCHN(evtchn)) {
 892                 struct sched_poll poll;
 893
 894                 poll.nr_ports = 1;
 895                 poll.timeout = 0;
 896                 set_xen_guest_handle(poll.ports, &evtchn);
 897
 898                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
 899                         BUG();
 900         }
 901 }
 902
 903 void xen_irq_resume(void)
 904 {
 905         unsigned int cpu, irq, evtchn;
 906
 907         init_evtchn_cpu_bindings();
 908
 909         /* New event-channel space is not 'live' yet. */
 910         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 911                 mask_evtchn(evtchn);
 912
 913         /* No IRQ <-> event-channel mappings. */
 914         for (irq = 0; irq < nr_irqs; irq++)
 915                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
 916
 917         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 918                 evtchn_to_irq[evtchn] = -1;
 919
 920         for_each_possible_cpu(cpu) {
 921                 restore_cpu_virqs(cpu);
 922                 restore_cpu_ipis(cpu);
 923         }
 924 }
 925
 926 static struct irq_chip xen_dynamic_chip __read_mostly = {
 927         .name           = "xen-dyn",
 928
 929         .disable        = disable_dynirq,
 930         .mask           = disable_dynirq,
 931         .unmask         = enable_dynirq,
 932
 933         .ack            = ack_dynirq,
 934         .set_affinity   = set_affinity_irq,
 935         .retrigger      = retrigger_dynirq,
 936 };
 937
 938 static struct irq_chip xen_percpu_chip __read_mostly = {
 939         .name           = "xen-percpu",
 940
 941         .disable        = disable_dynirq,
 942         .mask           = disable_dynirq,
 943         .unmask         = enable_dynirq,
 944
 945         .ack            = ack_dynirq,
 946 };
 947
 948 void __init xen_init_IRQ(void)
 949 {
 950         int i;
 951
 952         cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
 953                                     GFP_KERNEL);
 954         BUG_ON(cpu_evtchn_mask_p == NULL);
 955
 956         init_evtchn_cpu_bindings();
 957
 958         /* No event channels are 'live' right now. */
 959         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 960                 mask_evtchn(i);
 961
 962         irq_ctx_init(smp_processor_id());
 963 }