arch/ia64/xen/irq_xen.c

   1 /******************************************************************************
   2  * arch/ia64/xen/irq_xen.c
   3  *
   4  * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
   5  *                    VA Linux Systems Japan K.K.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  */
  22
  23 #include <linux/cpu.h>
  24
  25 #include <xen/interface/xen.h>
  26 #include <xen/interface/callback.h>
  27 #include <xen/events.h>
  28
  29 #include <asm/xen/privop.h>
  30
  31 #include "irq_xen.h"
  32
  33 /***************************************************************************
  34  * pv_irq_ops
  35  * irq operations
  36  */
  37
  38 static int
  39 xen_assign_irq_vector(int irq)
  40 {
  41         struct physdev_irq irq_op;
  42
  43         irq_op.irq = irq;
  44         if (HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op))
  45                 return -ENOSPC;
  46
  47         return irq_op.vector;
  48 }
  49
  50 static void
  51 xen_free_irq_vector(int vector)
  52 {
  53         struct physdev_irq irq_op;
  54
  55         if (vector < IA64_FIRST_DEVICE_VECTOR ||
  56             vector > IA64_LAST_DEVICE_VECTOR)
  57                 return;
  58
  59         irq_op.vector = vector;
  60         if (HYPERVISOR_physdev_op(PHYSDEVOP_free_irq_vector, &irq_op))
  61                 printk(KERN_WARNING "%s: xen_free_irq_vector fail vector=%d\n",
  62                        __func__, vector);
  63 }
  64
  65
  66 static DEFINE_PER_CPU(int, xen_timer_irq) = -1;
  67 static DEFINE_PER_CPU(int, xen_ipi_irq) = -1;
  68 static DEFINE_PER_CPU(int, xen_resched_irq) = -1;
  69 static DEFINE_PER_CPU(int, xen_cmc_irq) = -1;
  70 static DEFINE_PER_CPU(int, xen_cmcp_irq) = -1;
  71 static DEFINE_PER_CPU(int, xen_cpep_irq) = -1;
  72 #define NAME_SIZE       15
  73 static DEFINE_PER_CPU(char[NAME_SIZE], xen_timer_name);
  74 static DEFINE_PER_CPU(char[NAME_SIZE], xen_ipi_name);
  75 static DEFINE_PER_CPU(char[NAME_SIZE], xen_resched_name);
  76 static DEFINE_PER_CPU(char[NAME_SIZE], xen_cmc_name);
  77 static DEFINE_PER_CPU(char[NAME_SIZE], xen_cmcp_name);
  78 static DEFINE_PER_CPU(char[NAME_SIZE], xen_cpep_name);
  79 #undef NAME_SIZE
  80
  81 struct saved_irq {
  82         unsigned int irq;
  83         struct irqaction *action;
  84 };
  85 /* 16 should be far optimistic value, since only several percpu irqs
  86  * are registered early.
  87  */
  88 #define MAX_LATE_IRQ    16
  89 static struct saved_irq saved_percpu_irqs[MAX_LATE_IRQ];
  90 static unsigned short late_irq_cnt;
  91 static unsigned short saved_irq_cnt;
  92 static int xen_slab_ready;
  93
  94 #ifdef CONFIG_SMP
  95 #include <linux/sched.h>
  96
  97 /* Dummy stub. Though we may check XEN_RESCHEDULE_VECTOR before __do_IRQ,
  98  * it ends up to issue several memory accesses upon percpu data and
  99  * thus adds unnecessary traffic to other paths.
 100  */
 101 static irqreturn_t
 102 xen_dummy_handler(int irq, void *dev_id)
 103 {
 104         return IRQ_HANDLED;
 105 }
 106
 107 static irqreturn_t
 108 xen_resched_handler(int irq, void *dev_id)
 109 {
 110         scheduler_ipi();
 111         return IRQ_HANDLED;
 112 }
 113
 114 static struct irqaction xen_ipi_irqaction = {
 115         .handler =      handle_IPI,
 116         .flags =        IRQF_DISABLED,
 117         .name =         "IPI"
 118 };
 119
 120 static struct irqaction xen_resched_irqaction = {
 121         .handler =      xen_resched_handler,
 122         .flags =        IRQF_DISABLED,
 123         .name =         "resched"
 124 };
 125
 126 static struct irqaction xen_tlb_irqaction = {
 127         .handler =      xen_dummy_handler,
 128         .flags =        IRQF_DISABLED,
 129         .name =         "tlb_flush"
 130 };
 131 #endif
 132
 133 /*
 134  * This is xen version percpu irq registration, which needs bind
 135  * to xen specific evtchn sub-system. One trick here is that xen
 136  * evtchn binding interface depends on kmalloc because related
 137  * port needs to be freed at device/cpu down. So we cache the
 138  * registration on BSP before slab is ready and then deal them
 139  * at later point. For rest instances happening after slab ready,
 140  * we hook them to xen evtchn immediately.
 141  *
 142  * FIXME: MCA is not supported by far, and thus "nomca" boot param is
 143  * required.
 144  */
 145 static void
 146 __xen_register_percpu_irq(unsigned int cpu, unsigned int vec,
 147                         struct irqaction *action, int save)
 148 {
 149         int irq = 0;
 150
 151         if (xen_slab_ready) {
 152                 switch (vec) {
 153                 case IA64_TIMER_VECTOR:
 154                         snprintf(per_cpu(xen_timer_name, cpu),
 155                                  sizeof(per_cpu(xen_timer_name, cpu)),
 156                                  "%s%d", action->name, cpu);
 157                         irq = bind_virq_to_irqhandler(VIRQ_ITC, cpu,
 158                                 action->handler, action->flags,
 159                                 per_cpu(xen_timer_name, cpu), action->dev_id);
 160                         per_cpu(xen_timer_irq, cpu) = irq;
 161                         break;
 162                 case IA64_IPI_RESCHEDULE:
 163                         snprintf(per_cpu(xen_resched_name, cpu),
 164                                  sizeof(per_cpu(xen_resched_name, cpu)),
 165                                  "%s%d", action->name, cpu);
 166                         irq = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR, cpu,
 167                                 action->handler, action->flags,
 168                                 per_cpu(xen_resched_name, cpu), action->dev_id);
 169                         per_cpu(xen_resched_irq, cpu) = irq;
 170                         break;
 171                 case IA64_IPI_VECTOR:
 172                         snprintf(per_cpu(xen_ipi_name, cpu),
 173                                  sizeof(per_cpu(xen_ipi_name, cpu)),
 174                                  "%s%d", action->name, cpu);
 175                         irq = bind_ipi_to_irqhandler(XEN_IPI_VECTOR, cpu,
 176                                 action->handler, action->flags,
 177                                 per_cpu(xen_ipi_name, cpu), action->dev_id);
 178                         per_cpu(xen_ipi_irq, cpu) = irq;
 179                         break;
 180                 case IA64_CMC_VECTOR:
 181                         snprintf(per_cpu(xen_cmc_name, cpu),
 182                                  sizeof(per_cpu(xen_cmc_name, cpu)),
 183                                  "%s%d", action->name, cpu);
 184                         irq = bind_virq_to_irqhandler(VIRQ_MCA_CMC, cpu,
 185                                                 action->handler,
 186                                                 action->flags,
 187                                                 per_cpu(xen_cmc_name, cpu),
 188                                                 action->dev_id);
 189                         per_cpu(xen_cmc_irq, cpu) = irq;
 190                         break;
 191                 case IA64_CMCP_VECTOR:
 192                         snprintf(per_cpu(xen_cmcp_name, cpu),
 193                                  sizeof(per_cpu(xen_cmcp_name, cpu)),
 194                                  "%s%d", action->name, cpu);
 195                         irq = bind_ipi_to_irqhandler(XEN_CMCP_VECTOR, cpu,
 196                                                 action->handler,
 197                                                 action->flags,
 198                                                 per_cpu(xen_cmcp_name, cpu),
 199                                                 action->dev_id);
 200                         per_cpu(xen_cmcp_irq, cpu) = irq;
 201                         break;
 202                 case IA64_CPEP_VECTOR:
 203                         snprintf(per_cpu(xen_cpep_name, cpu),
 204                                  sizeof(per_cpu(xen_cpep_name, cpu)),
 205                                  "%s%d", action->name, cpu);
 206                         irq = bind_ipi_to_irqhandler(XEN_CPEP_VECTOR, cpu,
 207                                                 action->handler,
 208                                                 action->flags,
 209                                                 per_cpu(xen_cpep_name, cpu),
 210                                                 action->dev_id);
 211                         per_cpu(xen_cpep_irq, cpu) = irq;
 212                         break;
 213                 case IA64_CPE_VECTOR:
 214                 case IA64_MCA_RENDEZ_VECTOR:
 215                 case IA64_PERFMON_VECTOR:
 216                 case IA64_MCA_WAKEUP_VECTOR:
 217                 case IA64_SPURIOUS_INT_VECTOR:
 218                         /* No need to complain, these aren't supported. */
 219                         break;
 220                 default:
 221                         printk(KERN_WARNING "Percpu irq %d is unsupported "
 222                                "by xen!\n", vec);
 223                         break;
 224                 }
 225                 BUG_ON(irq < 0);
 226
 227                 if (irq > 0) {
 228                         /*
 229                          * Mark percpu.  Without this, migrate_irqs() will
 230                          * mark the interrupt for migrations and trigger it
 231                          * on cpu hotplug.
 232                          */
 233                         irq_set_status_flags(irq, IRQ_PER_CPU);
 234                 }
 235         }
 236
 237         /* For BSP, we cache registered percpu irqs, and then re-walk
 238          * them when initializing APs
 239          */
 240         if (!cpu && save) {
 241                 BUG_ON(saved_irq_cnt == MAX_LATE_IRQ);
 242                 saved_percpu_irqs[saved_irq_cnt].irq = vec;
 243                 saved_percpu_irqs[saved_irq_cnt].action = action;
 244                 saved_irq_cnt++;
 245                 if (!xen_slab_ready)
 246                         late_irq_cnt++;
 247         }
 248 }
 249
 250 static void
 251 xen_register_percpu_irq(ia64_vector vec, struct irqaction *action)
 252 {
 253         __xen_register_percpu_irq(smp_processor_id(), vec, action, 1);
 254 }
 255
 256 static void
 257 xen_bind_early_percpu_irq(void)
 258 {
 259         int i;
 260
 261         xen_slab_ready = 1;
 262         /* There's no race when accessing this cached array, since only
 263          * BSP will face with such step shortly
 264          */
 265         for (i = 0; i < late_irq_cnt; i++)
 266                 __xen_register_percpu_irq(smp_processor_id(),
 267                                           saved_percpu_irqs[i].irq,
 268                                           saved_percpu_irqs[i].action, 0);
 269 }
 270
 271 /* FIXME: There's no obvious point to check whether slab is ready. So
 272  * a hack is used here by utilizing a late time hook.
 273  */
 274
 275 #ifdef CONFIG_HOTPLUG_CPU
 276 static int unbind_evtchn_callback(struct notifier_block *nfb,
 277                                   unsigned long action, void *hcpu)
 278 {
 279         unsigned int cpu = (unsigned long)hcpu;
 280
 281         if (action == CPU_DEAD) {
 282                 /* Unregister evtchn.  */
 283                 if (per_cpu(xen_cpep_irq, cpu) >= 0) {
 284                         unbind_from_irqhandler(per_cpu(xen_cpep_irq, cpu),
 285                                                NULL);
 286                         per_cpu(xen_cpep_irq, cpu) = -1;
 287                 }
 288                 if (per_cpu(xen_cmcp_irq, cpu) >= 0) {
 289                         unbind_from_irqhandler(per_cpu(xen_cmcp_irq, cpu),
 290                                                NULL);
 291                         per_cpu(xen_cmcp_irq, cpu) = -1;
 292                 }
 293                 if (per_cpu(xen_cmc_irq, cpu) >= 0) {
 294                         unbind_from_irqhandler(per_cpu(xen_cmc_irq, cpu), NULL);
 295                         per_cpu(xen_cmc_irq, cpu) = -1;
 296                 }
 297                 if (per_cpu(xen_ipi_irq, cpu) >= 0) {
 298                         unbind_from_irqhandler(per_cpu(xen_ipi_irq, cpu), NULL);
 299                         per_cpu(xen_ipi_irq, cpu) = -1;
 300                 }
 301                 if (per_cpu(xen_resched_irq, cpu) >= 0) {
 302                         unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu),
 303                                                NULL);
 304                         per_cpu(xen_resched_irq, cpu) = -1;
 305                 }
 306                 if (per_cpu(xen_timer_irq, cpu) >= 0) {
 307                         unbind_from_irqhandler(per_cpu(xen_timer_irq, cpu),
 308                                                NULL);
 309                         per_cpu(xen_timer_irq, cpu) = -1;
 310                 }
 311         }
 312         return NOTIFY_OK;
 313 }
 314
 315 static struct notifier_block unbind_evtchn_notifier = {
 316         .notifier_call = unbind_evtchn_callback,
 317         .priority = 0
 318 };
 319 #endif
 320
 321 void xen_smp_intr_init_early(unsigned int cpu)
 322 {
 323 #ifdef CONFIG_SMP
 324         unsigned int i;
 325
 326         for (i = 0; i < saved_irq_cnt; i++)
 327                 __xen_register_percpu_irq(cpu, saved_percpu_irqs[i].irq,
 328                                           saved_percpu_irqs[i].action, 0);
 329 #endif
 330 }
 331
 332 void xen_smp_intr_init(void)
 333 {
 334 #ifdef CONFIG_SMP
 335         unsigned int cpu = smp_processor_id();
 336         struct callback_register event = {
 337                 .type = CALLBACKTYPE_event,
 338                 .address = { .ip = (unsigned long)&xen_event_callback },
 339         };
 340
 341         if (cpu == 0) {
 342                 /* Initialization was already done for boot cpu.  */
 343 #ifdef CONFIG_HOTPLUG_CPU
 344                 /* Register the notifier only once.  */
 345                 register_cpu_notifier(&unbind_evtchn_notifier);
 346 #endif
 347                 return;
 348         }
 349
 350         /* This should be piggyback when setup vcpu guest context */
 351         BUG_ON(HYPERVISOR_callback_op(CALLBACKOP_register, &event));
 352 #endif /* CONFIG_SMP */
 353 }
 354
 355 void __init
 356 xen_irq_init(void)
 357 {
 358         struct callback_register event = {
 359                 .type = CALLBACKTYPE_event,
 360                 .address = { .ip = (unsigned long)&xen_event_callback },
 361         };
 362
 363         xen_init_IRQ();
 364         BUG_ON(HYPERVISOR_callback_op(CALLBACKOP_register, &event));
 365         late_time_init = xen_bind_early_percpu_irq;
 366 }
 367
 368 void
 369 xen_platform_send_ipi(int cpu, int vector, int delivery_mode, int redirect)
 370 {
 371 #ifdef CONFIG_SMP
 372         /* TODO: we need to call vcpu_up here */
 373         if (unlikely(vector == ap_wakeup_vector)) {
 374                 /* XXX
 375                  * This should be in __cpu_up(cpu) in ia64 smpboot.c
 376                  * like x86. But don't want to modify it,
 377                  * keep it untouched.
 378                  */
 379                 xen_smp_intr_init_early(cpu);
 380
 381                 xen_send_ipi(cpu, vector);
 382                 /* vcpu_prepare_and_up(cpu); */
 383                 return;
 384         }
 385 #endif
 386
 387         switch (vector) {
 388         case IA64_IPI_VECTOR:
 389                 xen_send_IPI_one(cpu, XEN_IPI_VECTOR);
 390                 break;
 391         case IA64_IPI_RESCHEDULE:
 392                 xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
 393                 break;
 394         case IA64_CMCP_VECTOR:
 395                 xen_send_IPI_one(cpu, XEN_CMCP_VECTOR);
 396                 break;
 397         case IA64_CPEP_VECTOR:
 398                 xen_send_IPI_one(cpu, XEN_CPEP_VECTOR);
 399                 break;
 400         case IA64_TIMER_VECTOR: {
 401                 /* this is used only once by check_sal_cache_flush()
 402                    at boot time */
 403                 static int used = 0;
 404                 if (!used) {
 405                         xen_send_ipi(cpu, IA64_TIMER_VECTOR);
 406                         used = 1;
 407                         break;
 408                 }
 409                 /* fallthrough */
 410         }
 411         default:
 412                 printk(KERN_WARNING "Unsupported IPI type 0x%x\n",
 413                        vector);
 414                 notify_remote_via_irq(0); /* defaults to 0 irq */
 415                 break;
 416         }
 417 }
 418
 419 static void __init
 420 xen_register_ipi(void)
 421 {
 422 #ifdef CONFIG_SMP
 423         register_percpu_irq(IA64_IPI_VECTOR, &xen_ipi_irqaction);
 424         register_percpu_irq(IA64_IPI_RESCHEDULE, &xen_resched_irqaction);
 425         register_percpu_irq(IA64_IPI_LOCAL_TLB_FLUSH, &xen_tlb_irqaction);
 426 #endif
 427 }
 428
 429 static void
 430 xen_resend_irq(unsigned int vector)
 431 {
 432         (void)resend_irq_on_evtchn(vector);
 433 }
 434
 435 const struct pv_irq_ops xen_irq_ops __initconst = {
 436         .register_ipi = xen_register_ipi,
 437
 438         .assign_irq_vector = xen_assign_irq_vector,
 439         .free_irq_vector = xen_free_irq_vector,
 440         .register_percpu_irq = xen_register_percpu_irq,
 441
 442         .resend_irq = xen_resend_irq,
 443 };