linux/drivers/misc/sgi-xp/xpc_main.c
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   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
   7 * Copyright (c) 2004-2009 Silicon Graphics, Inc.  All Rights Reserved.
   8 */
   9
  10/*
  11 * Cross Partition Communication (XPC) support - standard version.
  12 *
  13 *      XPC provides a message passing capability that crosses partition
  14 *      boundaries. This module is made up of two parts:
  15 *
  16 *          partition   This part detects the presence/absence of other
  17 *                      partitions. It provides a heartbeat and monitors
  18 *                      the heartbeats of other partitions.
  19 *
  20 *          channel     This part manages the channels and sends/receives
  21 *                      messages across them to/from other partitions.
  22 *
  23 *      There are a couple of additional functions residing in XP, which
  24 *      provide an interface to XPC for its users.
  25 *
  26 *
  27 *      Caveats:
  28 *
  29 *        . Currently on sn2, we have no way to determine which nasid an IRQ
  30 *          came from. Thus, xpc_send_IRQ_sn2() does a remote amo write
  31 *          followed by an IPI. The amo indicates where data is to be pulled
  32 *          from, so after the IPI arrives, the remote partition checks the amo
  33 *          word. The IPI can actually arrive before the amo however, so other
  34 *          code must periodically check for this case. Also, remote amo
  35 *          operations do not reliably time out. Thus we do a remote PIO read
  36 *          solely to know whether the remote partition is down and whether we
  37 *          should stop sending IPIs to it. This remote PIO read operation is
  38 *          set up in a special nofault region so SAL knows to ignore (and
  39 *          cleanup) any errors due to the remote amo write, PIO read, and/or
  40 *          PIO write operations.
  41 *
  42 *          If/when new hardware solves this IPI problem, we should abandon
  43 *          the current approach.
  44 *
  45 */
  46
  47#include <linux/module.h>
  48#include <linux/slab.h>
  49#include <linux/sysctl.h>
  50#include <linux/device.h>
  51#include <linux/delay.h>
  52#include <linux/reboot.h>
  53#include <linux/kdebug.h>
  54#include <linux/kthread.h>
  55#include "xpc.h"
  56
  57#ifdef CONFIG_X86_64
  58#include <asm/traps.h>
  59#endif
  60
  61/* define two XPC debug device structures to be used with dev_dbg() et al */
  62
  63static struct device_driver xpc_dbg_name = {
  64        .name = "xpc"
  65};
  66
  67static struct device xpc_part_dbg_subname = {
  68        .init_name = "",        /* set to "part" at xpc_init() time */
  69        .driver = &xpc_dbg_name
  70};
  71
  72static struct device xpc_chan_dbg_subname = {
  73        .init_name = "",        /* set to "chan" at xpc_init() time */
  74        .driver = &xpc_dbg_name
  75};
  76
  77struct device *xpc_part = &xpc_part_dbg_subname;
  78struct device *xpc_chan = &xpc_chan_dbg_subname;
  79
  80static int xpc_kdebug_ignore;
  81
  82/* systune related variables for /proc/sys directories */
  83
  84static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
  85static int xpc_hb_min_interval = 1;
  86static int xpc_hb_max_interval = 10;
  87
  88static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
  89static int xpc_hb_check_min_interval = 10;
  90static int xpc_hb_check_max_interval = 120;
  91
  92int xpc_disengage_timelimit = XPC_DISENGAGE_DEFAULT_TIMELIMIT;
  93static int xpc_disengage_min_timelimit; /* = 0 */
  94static int xpc_disengage_max_timelimit = 120;
  95
  96static struct ctl_table xpc_sys_xpc_hb_dir[] = {
  97        {
  98         .procname = "hb_interval",
  99         .data = &xpc_hb_interval,
 100         .maxlen = sizeof(int),
 101         .mode = 0644,
 102         .proc_handler = proc_dointvec_minmax,
 103         .extra1 = &xpc_hb_min_interval,
 104         .extra2 = &xpc_hb_max_interval},
 105        {
 106         .procname = "hb_check_interval",
 107         .data = &xpc_hb_check_interval,
 108         .maxlen = sizeof(int),
 109         .mode = 0644,
 110         .proc_handler = proc_dointvec_minmax,
 111         .extra1 = &xpc_hb_check_min_interval,
 112         .extra2 = &xpc_hb_check_max_interval},
 113        {}
 114};
 115static struct ctl_table xpc_sys_xpc_dir[] = {
 116        {
 117         .procname = "hb",
 118         .mode = 0555,
 119         .child = xpc_sys_xpc_hb_dir},
 120        {
 121         .procname = "disengage_timelimit",
 122         .data = &xpc_disengage_timelimit,
 123         .maxlen = sizeof(int),
 124         .mode = 0644,
 125         .proc_handler = proc_dointvec_minmax,
 126         .extra1 = &xpc_disengage_min_timelimit,
 127         .extra2 = &xpc_disengage_max_timelimit},
 128        {}
 129};
 130static struct ctl_table xpc_sys_dir[] = {
 131        {
 132         .procname = "xpc",
 133         .mode = 0555,
 134         .child = xpc_sys_xpc_dir},
 135        {}
 136};
 137static struct ctl_table_header *xpc_sysctl;
 138
 139/* non-zero if any remote partition disengage was timed out */
 140int xpc_disengage_timedout;
 141
 142/* #of activate IRQs received and not yet processed */
 143int xpc_activate_IRQ_rcvd;
 144DEFINE_SPINLOCK(xpc_activate_IRQ_rcvd_lock);
 145
 146/* IRQ handler notifies this wait queue on receipt of an IRQ */
 147DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq);
 148
 149static unsigned long xpc_hb_check_timeout;
 150static struct timer_list xpc_hb_timer;
 151
 152/* notification that the xpc_hb_checker thread has exited */
 153static DECLARE_COMPLETION(xpc_hb_checker_exited);
 154
 155/* notification that the xpc_discovery thread has exited */
 156static DECLARE_COMPLETION(xpc_discovery_exited);
 157
 158static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
 159
 160static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
 161static struct notifier_block xpc_reboot_notifier = {
 162        .notifier_call = xpc_system_reboot,
 163};
 164
 165static int xpc_system_die(struct notifier_block *, unsigned long, void *);
 166static struct notifier_block xpc_die_notifier = {
 167        .notifier_call = xpc_system_die,
 168};
 169
 170struct xpc_arch_operations xpc_arch_ops;
 171
 172/*
 173 * Timer function to enforce the timelimit on the partition disengage.
 174 */
 175static void
 176xpc_timeout_partition_disengage(struct timer_list *t)
 177{
 178        struct xpc_partition *part = from_timer(part, t, disengage_timer);
 179
 180        DBUG_ON(time_is_after_jiffies(part->disengage_timeout));
 181
 182        xpc_partition_disengaged_from_timer(part);
 183
 184        DBUG_ON(part->disengage_timeout != 0);
 185        DBUG_ON(xpc_arch_ops.partition_engaged(XPC_PARTID(part)));
 186}
 187
 188/*
 189 * Timer to produce the heartbeat.  The timer structures function is
 190 * already set when this is initially called.  A tunable is used to
 191 * specify when the next timeout should occur.
 192 */
 193static void
 194xpc_hb_beater(struct timer_list *unused)
 195{
 196        xpc_arch_ops.increment_heartbeat();
 197
 198        if (time_is_before_eq_jiffies(xpc_hb_check_timeout))
 199                wake_up_interruptible(&xpc_activate_IRQ_wq);
 200
 201        xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
 202        add_timer(&xpc_hb_timer);
 203}
 204
 205static void
 206xpc_start_hb_beater(void)
 207{
 208        xpc_arch_ops.heartbeat_init();
 209        timer_setup(&xpc_hb_timer, xpc_hb_beater, 0);
 210        xpc_hb_beater(NULL);
 211}
 212
 213static void
 214xpc_stop_hb_beater(void)
 215{
 216        del_timer_sync(&xpc_hb_timer);
 217        xpc_arch_ops.heartbeat_exit();
 218}
 219
 220/*
 221 * At periodic intervals, scan through all active partitions and ensure
 222 * their heartbeat is still active.  If not, the partition is deactivated.
 223 */
 224static void
 225xpc_check_remote_hb(void)
 226{
 227        struct xpc_partition *part;
 228        short partid;
 229        enum xp_retval ret;
 230
 231        for (partid = 0; partid < xp_max_npartitions; partid++) {
 232
 233                if (xpc_exiting)
 234                        break;
 235
 236                if (partid == xp_partition_id)
 237                        continue;
 238
 239                part = &xpc_partitions[partid];
 240
 241                if (part->act_state == XPC_P_AS_INACTIVE ||
 242                    part->act_state == XPC_P_AS_DEACTIVATING) {
 243                        continue;
 244                }
 245
 246                ret = xpc_arch_ops.get_remote_heartbeat(part);
 247                if (ret != xpSuccess)
 248                        XPC_DEACTIVATE_PARTITION(part, ret);
 249        }
 250}
 251
 252/*
 253 * This thread is responsible for nearly all of the partition
 254 * activation/deactivation.
 255 */
 256static int
 257xpc_hb_checker(void *ignore)
 258{
 259        int force_IRQ = 0;
 260
 261        /* this thread was marked active by xpc_hb_init() */
 262
 263        set_cpus_allowed_ptr(current, cpumask_of(XPC_HB_CHECK_CPU));
 264
 265        /* set our heartbeating to other partitions into motion */
 266        xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
 267        xpc_start_hb_beater();
 268
 269        while (!xpc_exiting) {
 270
 271                dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
 272                        "been received\n",
 273                        (int)(xpc_hb_check_timeout - jiffies),
 274                        xpc_activate_IRQ_rcvd);
 275
 276                /* checking of remote heartbeats is skewed by IRQ handling */
 277                if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) {
 278                        xpc_hb_check_timeout = jiffies +
 279                            (xpc_hb_check_interval * HZ);
 280
 281                        dev_dbg(xpc_part, "checking remote heartbeats\n");
 282                        xpc_check_remote_hb();
 283                }
 284
 285                /* check for outstanding IRQs */
 286                if (xpc_activate_IRQ_rcvd > 0 || force_IRQ != 0) {
 287                        force_IRQ = 0;
 288                        dev_dbg(xpc_part, "processing activate IRQs "
 289                                "received\n");
 290                        xpc_arch_ops.process_activate_IRQ_rcvd();
 291                }
 292
 293                /* wait for IRQ or timeout */
 294                (void)wait_event_interruptible(xpc_activate_IRQ_wq,
 295                                               (time_is_before_eq_jiffies(
 296                                                xpc_hb_check_timeout) ||
 297                                                xpc_activate_IRQ_rcvd > 0 ||
 298                                                xpc_exiting));
 299        }
 300
 301        xpc_stop_hb_beater();
 302
 303        dev_dbg(xpc_part, "heartbeat checker is exiting\n");
 304
 305        /* mark this thread as having exited */
 306        complete(&xpc_hb_checker_exited);
 307        return 0;
 308}
 309
 310/*
 311 * This thread will attempt to discover other partitions to activate
 312 * based on info provided by SAL. This new thread is short lived and
 313 * will exit once discovery is complete.
 314 */
 315static int
 316xpc_initiate_discovery(void *ignore)
 317{
 318        xpc_discovery();
 319
 320        dev_dbg(xpc_part, "discovery thread is exiting\n");
 321
 322        /* mark this thread as having exited */
 323        complete(&xpc_discovery_exited);
 324        return 0;
 325}
 326
 327/*
 328 * The first kthread assigned to a newly activated partition is the one
 329 * created by XPC HB with which it calls xpc_activating(). XPC hangs on to
 330 * that kthread until the partition is brought down, at which time that kthread
 331 * returns back to XPC HB. (The return of that kthread will signify to XPC HB
 332 * that XPC has dismantled all communication infrastructure for the associated
 333 * partition.) This kthread becomes the channel manager for that partition.
 334 *
 335 * Each active partition has a channel manager, who, besides connecting and
 336 * disconnecting channels, will ensure that each of the partition's connected
 337 * channels has the required number of assigned kthreads to get the work done.
 338 */
 339static void
 340xpc_channel_mgr(struct xpc_partition *part)
 341{
 342        while (part->act_state != XPC_P_AS_DEACTIVATING ||
 343               atomic_read(&part->nchannels_active) > 0 ||
 344               !xpc_partition_disengaged(part)) {
 345
 346                xpc_process_sent_chctl_flags(part);
 347
 348                /*
 349                 * Wait until we've been requested to activate kthreads or
 350                 * all of the channel's message queues have been torn down or
 351                 * a signal is pending.
 352                 *
 353                 * The channel_mgr_requests is set to 1 after being awakened,
 354                 * This is done to prevent the channel mgr from making one pass
 355                 * through the loop for each request, since he will
 356                 * be servicing all the requests in one pass. The reason it's
 357                 * set to 1 instead of 0 is so that other kthreads will know
 358                 * that the channel mgr is running and won't bother trying to
 359                 * wake him up.
 360                 */
 361                atomic_dec(&part->channel_mgr_requests);
 362                (void)wait_event_interruptible(part->channel_mgr_wq,
 363                                (atomic_read(&part->channel_mgr_requests) > 0 ||
 364                                 part->chctl.all_flags != 0 ||
 365                                 (part->act_state == XPC_P_AS_DEACTIVATING &&
 366                                 atomic_read(&part->nchannels_active) == 0 &&
 367                                 xpc_partition_disengaged(part))));
 368                atomic_set(&part->channel_mgr_requests, 1);
 369        }
 370}
 371
 372/*
 373 * Guarantee that the kzalloc'd memory is cacheline aligned.
 374 */
 375void *
 376xpc_kzalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
 377{
 378        /* see if kzalloc will give us cachline aligned memory by default */
 379        *base = kzalloc(size, flags);
 380        if (*base == NULL)
 381                return NULL;
 382
 383        if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
 384                return *base;
 385
 386        kfree(*base);
 387
 388        /* nope, we'll have to do it ourselves */
 389        *base = kzalloc(size + L1_CACHE_BYTES, flags);
 390        if (*base == NULL)
 391                return NULL;
 392
 393        return (void *)L1_CACHE_ALIGN((u64)*base);
 394}
 395
 396/*
 397 * Setup the channel structures necessary to support XPartition Communication
 398 * between the specified remote partition and the local one.
 399 */
 400static enum xp_retval
 401xpc_setup_ch_structures(struct xpc_partition *part)
 402{
 403        enum xp_retval ret;
 404        int ch_number;
 405        struct xpc_channel *ch;
 406        short partid = XPC_PARTID(part);
 407
 408        /*
 409         * Allocate all of the channel structures as a contiguous chunk of
 410         * memory.
 411         */
 412        DBUG_ON(part->channels != NULL);
 413        part->channels = kcalloc(XPC_MAX_NCHANNELS,
 414                                 sizeof(struct xpc_channel),
 415                                 GFP_KERNEL);
 416        if (part->channels == NULL) {
 417                dev_err(xpc_chan, "can't get memory for channels\n");
 418                return xpNoMemory;
 419        }
 420
 421        /* allocate the remote open and close args */
 422
 423        part->remote_openclose_args =
 424            xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE,
 425                                          GFP_KERNEL, &part->
 426                                          remote_openclose_args_base);
 427        if (part->remote_openclose_args == NULL) {
 428                dev_err(xpc_chan, "can't get memory for remote connect args\n");
 429                ret = xpNoMemory;
 430                goto out_1;
 431        }
 432
 433        part->chctl.all_flags = 0;
 434        spin_lock_init(&part->chctl_lock);
 435
 436        atomic_set(&part->channel_mgr_requests, 1);
 437        init_waitqueue_head(&part->channel_mgr_wq);
 438
 439        part->nchannels = XPC_MAX_NCHANNELS;
 440
 441        atomic_set(&part->nchannels_active, 0);
 442        atomic_set(&part->nchannels_engaged, 0);
 443
 444        for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
 445                ch = &part->channels[ch_number];
 446
 447                ch->partid = partid;
 448                ch->number = ch_number;
 449                ch->flags = XPC_C_DISCONNECTED;
 450
 451                atomic_set(&ch->kthreads_assigned, 0);
 452                atomic_set(&ch->kthreads_idle, 0);
 453                atomic_set(&ch->kthreads_active, 0);
 454
 455                atomic_set(&ch->references, 0);
 456                atomic_set(&ch->n_to_notify, 0);
 457
 458                spin_lock_init(&ch->lock);
 459                init_completion(&ch->wdisconnect_wait);
 460
 461                atomic_set(&ch->n_on_msg_allocate_wq, 0);
 462                init_waitqueue_head(&ch->msg_allocate_wq);
 463                init_waitqueue_head(&ch->idle_wq);
 464        }
 465
 466        ret = xpc_arch_ops.setup_ch_structures(part);
 467        if (ret != xpSuccess)
 468                goto out_2;
 469
 470        /*
 471         * With the setting of the partition setup_state to XPC_P_SS_SETUP,
 472         * we're declaring that this partition is ready to go.
 473         */
 474        part->setup_state = XPC_P_SS_SETUP;
 475
 476        return xpSuccess;
 477
 478        /* setup of ch structures failed */
 479out_2:
 480        kfree(part->remote_openclose_args_base);
 481        part->remote_openclose_args = NULL;
 482out_1:
 483        kfree(part->channels);
 484        part->channels = NULL;
 485        return ret;
 486}
 487
 488/*
 489 * Teardown the channel structures necessary to support XPartition Communication
 490 * between the specified remote partition and the local one.
 491 */
 492static void
 493xpc_teardown_ch_structures(struct xpc_partition *part)
 494{
 495        DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
 496        DBUG_ON(atomic_read(&part->nchannels_active) != 0);
 497
 498        /*
 499         * Make this partition inaccessible to local processes by marking it
 500         * as no longer setup. Then wait before proceeding with the teardown
 501         * until all existing references cease.
 502         */
 503        DBUG_ON(part->setup_state != XPC_P_SS_SETUP);
 504        part->setup_state = XPC_P_SS_WTEARDOWN;
 505
 506        wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));
 507
 508        /* now we can begin tearing down the infrastructure */
 509
 510        xpc_arch_ops.teardown_ch_structures(part);
 511
 512        kfree(part->remote_openclose_args_base);
 513        part->remote_openclose_args = NULL;
 514        kfree(part->channels);
 515        part->channels = NULL;
 516
 517        part->setup_state = XPC_P_SS_TORNDOWN;
 518}
 519
 520/*
 521 * When XPC HB determines that a partition has come up, it will create a new
 522 * kthread and that kthread will call this function to attempt to set up the
 523 * basic infrastructure used for Cross Partition Communication with the newly
 524 * upped partition.
 525 *
 526 * The kthread that was created by XPC HB and which setup the XPC
 527 * infrastructure will remain assigned to the partition becoming the channel
 528 * manager for that partition until the partition is deactivating, at which
 529 * time the kthread will teardown the XPC infrastructure and then exit.
 530 */
 531static int
 532xpc_activating(void *__partid)
 533{
 534        short partid = (u64)__partid;
 535        struct xpc_partition *part = &xpc_partitions[partid];
 536        unsigned long irq_flags;
 537
 538        DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
 539
 540        spin_lock_irqsave(&part->act_lock, irq_flags);
 541
 542        if (part->act_state == XPC_P_AS_DEACTIVATING) {
 543                part->act_state = XPC_P_AS_INACTIVE;
 544                spin_unlock_irqrestore(&part->act_lock, irq_flags);
 545                part->remote_rp_pa = 0;
 546                return 0;
 547        }
 548
 549        /* indicate the thread is activating */
 550        DBUG_ON(part->act_state != XPC_P_AS_ACTIVATION_REQ);
 551        part->act_state = XPC_P_AS_ACTIVATING;
 552
 553        XPC_SET_REASON(part, 0, 0);
 554        spin_unlock_irqrestore(&part->act_lock, irq_flags);
 555
 556        dev_dbg(xpc_part, "activating partition %d\n", partid);
 557
 558        xpc_arch_ops.allow_hb(partid);
 559
 560        if (xpc_setup_ch_structures(part) == xpSuccess) {
 561                (void)xpc_part_ref(part);       /* this will always succeed */
 562
 563                if (xpc_arch_ops.make_first_contact(part) == xpSuccess) {
 564                        xpc_mark_partition_active(part);
 565                        xpc_channel_mgr(part);
 566                        /* won't return until partition is deactivating */
 567                }
 568
 569                xpc_part_deref(part);
 570                xpc_teardown_ch_structures(part);
 571        }
 572
 573        xpc_arch_ops.disallow_hb(partid);
 574        xpc_mark_partition_inactive(part);
 575
 576        if (part->reason == xpReactivating) {
 577                /* interrupting ourselves results in activating partition */
 578                xpc_arch_ops.request_partition_reactivation(part);
 579        }
 580
 581        return 0;
 582}
 583
 584void
 585xpc_activate_partition(struct xpc_partition *part)
 586{
 587        short partid = XPC_PARTID(part);
 588        unsigned long irq_flags;
 589        struct task_struct *kthread;
 590
 591        spin_lock_irqsave(&part->act_lock, irq_flags);
 592
 593        DBUG_ON(part->act_state != XPC_P_AS_INACTIVE);
 594
 595        part->act_state = XPC_P_AS_ACTIVATION_REQ;
 596        XPC_SET_REASON(part, xpCloneKThread, __LINE__);
 597
 598        spin_unlock_irqrestore(&part->act_lock, irq_flags);
 599
 600        kthread = kthread_run(xpc_activating, (void *)((u64)partid), "xpc%02d",
 601                              partid);
 602        if (IS_ERR(kthread)) {
 603                spin_lock_irqsave(&part->act_lock, irq_flags);
 604                part->act_state = XPC_P_AS_INACTIVE;
 605                XPC_SET_REASON(part, xpCloneKThreadFailed, __LINE__);
 606                spin_unlock_irqrestore(&part->act_lock, irq_flags);
 607        }
 608}
 609
 610void
 611xpc_activate_kthreads(struct xpc_channel *ch, int needed)
 612{
 613        int idle = atomic_read(&ch->kthreads_idle);
 614        int assigned = atomic_read(&ch->kthreads_assigned);
 615        int wakeup;
 616
 617        DBUG_ON(needed <= 0);
 618
 619        if (idle > 0) {
 620                wakeup = (needed > idle) ? idle : needed;
 621                needed -= wakeup;
 622
 623                dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
 624                        "channel=%d\n", wakeup, ch->partid, ch->number);
 625
 626                /* only wakeup the requested number of kthreads */
 627                wake_up_nr(&ch->idle_wq, wakeup);
 628        }
 629
 630        if (needed <= 0)
 631                return;
 632
 633        if (needed + assigned > ch->kthreads_assigned_limit) {
 634                needed = ch->kthreads_assigned_limit - assigned;
 635                if (needed <= 0)
 636                        return;
 637        }
 638
 639        dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
 640                needed, ch->partid, ch->number);
 641
 642        xpc_create_kthreads(ch, needed, 0);
 643}
 644
 645/*
 646 * This function is where XPC's kthreads wait for messages to deliver.
 647 */
 648static void
 649xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
 650{
 651        int (*n_of_deliverable_payloads) (struct xpc_channel *) =
 652                xpc_arch_ops.n_of_deliverable_payloads;
 653
 654        do {
 655                /* deliver messages to their intended recipients */
 656
 657                while (n_of_deliverable_payloads(ch) > 0 &&
 658                       !(ch->flags & XPC_C_DISCONNECTING)) {
 659                        xpc_deliver_payload(ch);
 660                }
 661
 662                if (atomic_inc_return(&ch->kthreads_idle) >
 663                    ch->kthreads_idle_limit) {
 664                        /* too many idle kthreads on this channel */
 665                        atomic_dec(&ch->kthreads_idle);
 666                        break;
 667                }
 668
 669                dev_dbg(xpc_chan, "idle kthread calling "
 670                        "wait_event_interruptible_exclusive()\n");
 671
 672                (void)wait_event_interruptible_exclusive(ch->idle_wq,
 673                                (n_of_deliverable_payloads(ch) > 0 ||
 674                                 (ch->flags & XPC_C_DISCONNECTING)));
 675
 676                atomic_dec(&ch->kthreads_idle);
 677
 678        } while (!(ch->flags & XPC_C_DISCONNECTING));
 679}
 680
 681static int
 682xpc_kthread_start(void *args)
 683{
 684        short partid = XPC_UNPACK_ARG1(args);
 685        u16 ch_number = XPC_UNPACK_ARG2(args);
 686        struct xpc_partition *part = &xpc_partitions[partid];
 687        struct xpc_channel *ch;
 688        int n_needed;
 689        unsigned long irq_flags;
 690        int (*n_of_deliverable_payloads) (struct xpc_channel *) =
 691                xpc_arch_ops.n_of_deliverable_payloads;
 692
 693        dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
 694                partid, ch_number);
 695
 696        ch = &part->channels[ch_number];
 697
 698        if (!(ch->flags & XPC_C_DISCONNECTING)) {
 699
 700                /* let registerer know that connection has been established */
 701
 702                spin_lock_irqsave(&ch->lock, irq_flags);
 703                if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
 704                        ch->flags |= XPC_C_CONNECTEDCALLOUT;
 705                        spin_unlock_irqrestore(&ch->lock, irq_flags);
 706
 707                        xpc_connected_callout(ch);
 708
 709                        spin_lock_irqsave(&ch->lock, irq_flags);
 710                        ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
 711                        spin_unlock_irqrestore(&ch->lock, irq_flags);
 712
 713                        /*
 714                         * It is possible that while the callout was being
 715                         * made that the remote partition sent some messages.
 716                         * If that is the case, we may need to activate
 717                         * additional kthreads to help deliver them. We only
 718                         * need one less than total #of messages to deliver.
 719                         */
 720                        n_needed = n_of_deliverable_payloads(ch) - 1;
 721                        if (n_needed > 0 && !(ch->flags & XPC_C_DISCONNECTING))
 722                                xpc_activate_kthreads(ch, n_needed);
 723
 724                } else {
 725                        spin_unlock_irqrestore(&ch->lock, irq_flags);
 726                }
 727
 728                xpc_kthread_waitmsgs(part, ch);
 729        }
 730
 731        /* let registerer know that connection is disconnecting */
 732
 733        spin_lock_irqsave(&ch->lock, irq_flags);
 734        if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
 735            !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
 736                ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
 737                spin_unlock_irqrestore(&ch->lock, irq_flags);
 738
 739                xpc_disconnect_callout(ch, xpDisconnecting);
 740
 741                spin_lock_irqsave(&ch->lock, irq_flags);
 742                ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
 743        }
 744        spin_unlock_irqrestore(&ch->lock, irq_flags);
 745
 746        if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 747            atomic_dec_return(&part->nchannels_engaged) == 0) {
 748                xpc_arch_ops.indicate_partition_disengaged(part);
 749        }
 750
 751        xpc_msgqueue_deref(ch);
 752
 753        dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
 754                partid, ch_number);
 755
 756        xpc_part_deref(part);
 757        return 0;
 758}
 759
 760/*
 761 * For each partition that XPC has established communications with, there is
 762 * a minimum of one kernel thread assigned to perform any operation that
 763 * may potentially sleep or block (basically the callouts to the asynchronous
 764 * functions registered via xpc_connect()).
 765 *
 766 * Additional kthreads are created and destroyed by XPC as the workload
 767 * demands.
 768 *
 769 * A kthread is assigned to one of the active channels that exists for a given
 770 * partition.
 771 */
 772void
 773xpc_create_kthreads(struct xpc_channel *ch, int needed,
 774                    int ignore_disconnecting)
 775{
 776        unsigned long irq_flags;
 777        u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
 778        struct xpc_partition *part = &xpc_partitions[ch->partid];
 779        struct task_struct *kthread;
 780        void (*indicate_partition_disengaged) (struct xpc_partition *) =
 781                xpc_arch_ops.indicate_partition_disengaged;
 782
 783        while (needed-- > 0) {
 784
 785                /*
 786                 * The following is done on behalf of the newly created
 787                 * kthread. That kthread is responsible for doing the
 788                 * counterpart to the following before it exits.
 789                 */
 790                if (ignore_disconnecting) {
 791                        if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
 792                                /* kthreads assigned had gone to zero */
 793                                BUG_ON(!(ch->flags &
 794                                         XPC_C_DISCONNECTINGCALLOUT_MADE));
 795                                break;
 796                        }
 797
 798                } else if (ch->flags & XPC_C_DISCONNECTING) {
 799                        break;
 800
 801                } else if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
 802                           atomic_inc_return(&part->nchannels_engaged) == 1) {
 803                        xpc_arch_ops.indicate_partition_engaged(part);
 804                }
 805                (void)xpc_part_ref(part);
 806                xpc_msgqueue_ref(ch);
 807
 808                kthread = kthread_run(xpc_kthread_start, (void *)args,
 809                                      "xpc%02dc%d", ch->partid, ch->number);
 810                if (IS_ERR(kthread)) {
 811                        /* the fork failed */
 812
 813                        /*
 814                         * NOTE: if (ignore_disconnecting &&
 815                         * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
 816                         * then we'll deadlock if all other kthreads assigned
 817                         * to this channel are blocked in the channel's
 818                         * registerer, because the only thing that will unblock
 819                         * them is the xpDisconnecting callout that this
 820                         * failed kthread_run() would have made.
 821                         */
 822
 823                        if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 824                            atomic_dec_return(&part->nchannels_engaged) == 0) {
 825                                indicate_partition_disengaged(part);
 826                        }
 827                        xpc_msgqueue_deref(ch);
 828                        xpc_part_deref(part);
 829
 830                        if (atomic_read(&ch->kthreads_assigned) <
 831                            ch->kthreads_idle_limit) {
 832                                /*
 833                                 * Flag this as an error only if we have an
 834                                 * insufficient #of kthreads for the channel
 835                                 * to function.
 836                                 */
 837                                spin_lock_irqsave(&ch->lock, irq_flags);
 838                                XPC_DISCONNECT_CHANNEL(ch, xpLackOfResources,
 839                                                       &irq_flags);
 840                                spin_unlock_irqrestore(&ch->lock, irq_flags);
 841                        }
 842                        break;
 843                }
 844        }
 845}
 846
 847void
 848xpc_disconnect_wait(int ch_number)
 849{
 850        unsigned long irq_flags;
 851        short partid;
 852        struct xpc_partition *part;
 853        struct xpc_channel *ch;
 854        int wakeup_channel_mgr;
 855
 856        /* now wait for all callouts to the caller's function to cease */
 857        for (partid = 0; partid < xp_max_npartitions; partid++) {
 858                part = &xpc_partitions[partid];
 859
 860                if (!xpc_part_ref(part))
 861                        continue;
 862
 863                ch = &part->channels[ch_number];
 864
 865                if (!(ch->flags & XPC_C_WDISCONNECT)) {
 866                        xpc_part_deref(part);
 867                        continue;
 868                }
 869
 870                wait_for_completion(&ch->wdisconnect_wait);
 871
 872                spin_lock_irqsave(&ch->lock, irq_flags);
 873                DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
 874                wakeup_channel_mgr = 0;
 875
 876                if (ch->delayed_chctl_flags) {
 877                        if (part->act_state != XPC_P_AS_DEACTIVATING) {
 878                                spin_lock(&part->chctl_lock);
 879                                part->chctl.flags[ch->number] |=
 880                                    ch->delayed_chctl_flags;
 881                                spin_unlock(&part->chctl_lock);
 882                                wakeup_channel_mgr = 1;
 883                        }
 884                        ch->delayed_chctl_flags = 0;
 885                }
 886
 887                ch->flags &= ~XPC_C_WDISCONNECT;
 888                spin_unlock_irqrestore(&ch->lock, irq_flags);
 889
 890                if (wakeup_channel_mgr)
 891                        xpc_wakeup_channel_mgr(part);
 892
 893                xpc_part_deref(part);
 894        }
 895}
 896
 897static int
 898xpc_setup_partitions(void)
 899{
 900        short partid;
 901        struct xpc_partition *part;
 902
 903        xpc_partitions = kcalloc(xp_max_npartitions,
 904                                 sizeof(struct xpc_partition),
 905                                 GFP_KERNEL);
 906        if (xpc_partitions == NULL) {
 907                dev_err(xpc_part, "can't get memory for partition structure\n");
 908                return -ENOMEM;
 909        }
 910
 911        /*
 912         * The first few fields of each entry of xpc_partitions[] need to
 913         * be initialized now so that calls to xpc_connect() and
 914         * xpc_disconnect() can be made prior to the activation of any remote
 915         * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
 916         * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
 917         * PARTITION HAS BEEN ACTIVATED.
 918         */
 919        for (partid = 0; partid < xp_max_npartitions; partid++) {
 920                part = &xpc_partitions[partid];
 921
 922                DBUG_ON((u64)part != L1_CACHE_ALIGN((u64)part));
 923
 924                part->activate_IRQ_rcvd = 0;
 925                spin_lock_init(&part->act_lock);
 926                part->act_state = XPC_P_AS_INACTIVE;
 927                XPC_SET_REASON(part, 0, 0);
 928
 929                timer_setup(&part->disengage_timer,
 930                            xpc_timeout_partition_disengage, 0);
 931
 932                part->setup_state = XPC_P_SS_UNSET;
 933                init_waitqueue_head(&part->teardown_wq);
 934                atomic_set(&part->references, 0);
 935        }
 936
 937        return xpc_arch_ops.setup_partitions();
 938}
 939
 940static void
 941xpc_teardown_partitions(void)
 942{
 943        xpc_arch_ops.teardown_partitions();
 944        kfree(xpc_partitions);
 945}
 946
 947static void
 948xpc_do_exit(enum xp_retval reason)
 949{
 950        short partid;
 951        int active_part_count, printed_waiting_msg = 0;
 952        struct xpc_partition *part;
 953        unsigned long printmsg_time, disengage_timeout = 0;
 954
 955        /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
 956        DBUG_ON(xpc_exiting == 1);
 957
 958        /*
 959         * Let the heartbeat checker thread and the discovery thread
 960         * (if one is running) know that they should exit. Also wake up
 961         * the heartbeat checker thread in case it's sleeping.
 962         */
 963        xpc_exiting = 1;
 964        wake_up_interruptible(&xpc_activate_IRQ_wq);
 965
 966        /* wait for the discovery thread to exit */
 967        wait_for_completion(&xpc_discovery_exited);
 968
 969        /* wait for the heartbeat checker thread to exit */
 970        wait_for_completion(&xpc_hb_checker_exited);
 971
 972        /* sleep for a 1/3 of a second or so */
 973        (void)msleep_interruptible(300);
 974
 975        /* wait for all partitions to become inactive */
 976
 977        printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
 978        xpc_disengage_timedout = 0;
 979
 980        do {
 981                active_part_count = 0;
 982
 983                for (partid = 0; partid < xp_max_npartitions; partid++) {
 984                        part = &xpc_partitions[partid];
 985
 986                        if (xpc_partition_disengaged(part) &&
 987                            part->act_state == XPC_P_AS_INACTIVE) {
 988                                continue;
 989                        }
 990
 991                        active_part_count++;
 992
 993                        XPC_DEACTIVATE_PARTITION(part, reason);
 994
 995                        if (part->disengage_timeout > disengage_timeout)
 996                                disengage_timeout = part->disengage_timeout;
 997                }
 998
 999                if (xpc_arch_ops.any_partition_engaged()) {
1000                        if (time_is_before_jiffies(printmsg_time)) {
1001                                dev_info(xpc_part, "waiting for remote "
1002                                         "partitions to deactivate, timeout in "
1003                                         "%ld seconds\n", (disengage_timeout -
1004                                         jiffies) / HZ);
1005                                printmsg_time = jiffies +
1006                                    (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
1007                                printed_waiting_msg = 1;
1008                        }
1009
1010                } else if (active_part_count > 0) {
1011                        if (printed_waiting_msg) {
1012                                dev_info(xpc_part, "waiting for local partition"
1013                                         " to deactivate\n");
1014                                printed_waiting_msg = 0;
1015                        }
1016
1017                } else {
1018                        if (!xpc_disengage_timedout) {
1019                                dev_info(xpc_part, "all partitions have "
1020                                         "deactivated\n");
1021                        }
1022                        break;
1023                }
1024
1025                /* sleep for a 1/3 of a second or so */
1026                (void)msleep_interruptible(300);
1027
1028        } while (1);
1029
1030        DBUG_ON(xpc_arch_ops.any_partition_engaged());
1031
1032        xpc_teardown_rsvd_page();
1033
1034        if (reason == xpUnloading) {
1035                (void)unregister_die_notifier(&xpc_die_notifier);
1036                (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1037        }
1038
1039        /* clear the interface to XPC's functions */
1040        xpc_clear_interface();
1041
1042        if (xpc_sysctl)
1043                unregister_sysctl_table(xpc_sysctl);
1044
1045        xpc_teardown_partitions();
1046
1047        if (is_uv_system())
1048                xpc_exit_uv();
1049}
1050
1051/*
1052 * This function is called when the system is being rebooted.
1053 */
1054static int
1055xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1056{
1057        enum xp_retval reason;
1058
1059        switch (event) {
1060        case SYS_RESTART:
1061                reason = xpSystemReboot;
1062                break;
1063        case SYS_HALT:
1064                reason = xpSystemHalt;
1065                break;
1066        case SYS_POWER_OFF:
1067                reason = xpSystemPoweroff;
1068                break;
1069        default:
1070                reason = xpSystemGoingDown;
1071        }
1072
1073        xpc_do_exit(reason);
1074        return NOTIFY_DONE;
1075}
1076
1077/* Used to only allow one cpu to complete disconnect */
1078static unsigned int xpc_die_disconnecting;
1079
1080/*
1081 * Notify other partitions to deactivate from us by first disengaging from all
1082 * references to our memory.
1083 */
1084static void
1085xpc_die_deactivate(void)
1086{
1087        struct xpc_partition *part;
1088        short partid;
1089        int any_engaged;
1090        long keep_waiting;
1091        long wait_to_print;
1092
1093        if (cmpxchg(&xpc_die_disconnecting, 0, 1))
1094                return;
1095
1096        /* keep xpc_hb_checker thread from doing anything (just in case) */
1097        xpc_exiting = 1;
1098
1099        xpc_arch_ops.disallow_all_hbs();   /*indicate we're deactivated */
1100
1101        for (partid = 0; partid < xp_max_npartitions; partid++) {
1102                part = &xpc_partitions[partid];
1103
1104                if (xpc_arch_ops.partition_engaged(partid) ||
1105                    part->act_state != XPC_P_AS_INACTIVE) {
1106                        xpc_arch_ops.request_partition_deactivation(part);
1107                        xpc_arch_ops.indicate_partition_disengaged(part);
1108                }
1109        }
1110
1111        /*
1112         * Though we requested that all other partitions deactivate from us,
1113         * we only wait until they've all disengaged or we've reached the
1114         * defined timelimit.
1115         *
1116         * Given that one iteration through the following while-loop takes
1117         * approximately 200 microseconds, calculate the #of loops to take
1118         * before bailing and the #of loops before printing a waiting message.
1119         */
1120        keep_waiting = xpc_disengage_timelimit * 1000 * 5;
1121        wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5;
1122
1123        while (1) {
1124                any_engaged = xpc_arch_ops.any_partition_engaged();
1125                if (!any_engaged) {
1126                        dev_info(xpc_part, "all partitions have deactivated\n");
1127                        break;
1128                }
1129
1130                if (!keep_waiting--) {
1131                        for (partid = 0; partid < xp_max_npartitions;
1132                             partid++) {
1133                                if (xpc_arch_ops.partition_engaged(partid)) {
1134                                        dev_info(xpc_part, "deactivate from "
1135                                                 "remote partition %d timed "
1136                                                 "out\n", partid);
1137                                }
1138                        }
1139                        break;
1140                }
1141
1142                if (!wait_to_print--) {
1143                        dev_info(xpc_part, "waiting for remote partitions to "
1144                                 "deactivate, timeout in %ld seconds\n",
1145                                 keep_waiting / (1000 * 5));
1146                        wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL *
1147                            1000 * 5;
1148                }
1149
1150                udelay(200);
1151        }
1152}
1153
1154/*
1155 * This function is called when the system is being restarted or halted due
1156 * to some sort of system failure. If this is the case we need to notify the
1157 * other partitions to disengage from all references to our memory.
1158 * This function can also be called when our heartbeater could be offlined
1159 * for a time. In this case we need to notify other partitions to not worry
1160 * about the lack of a heartbeat.
1161 */
1162static int
1163xpc_system_die(struct notifier_block *nb, unsigned long event, void *_die_args)
1164{
1165#ifdef CONFIG_IA64              /* !!! temporary kludge */
1166        switch (event) {
1167        case DIE_MACHINE_RESTART:
1168        case DIE_MACHINE_HALT:
1169                xpc_die_deactivate();
1170                break;
1171
1172        case DIE_KDEBUG_ENTER:
1173                /* Should lack of heartbeat be ignored by other partitions? */
1174                if (!xpc_kdebug_ignore)
1175                        break;
1176
1177                fallthrough;
1178        case DIE_MCA_MONARCH_ENTER:
1179        case DIE_INIT_MONARCH_ENTER:
1180                xpc_arch_ops.offline_heartbeat();
1181                break;
1182
1183        case DIE_KDEBUG_LEAVE:
1184                /* Is lack of heartbeat being ignored by other partitions? */
1185                if (!xpc_kdebug_ignore)
1186                        break;
1187
1188                fallthrough;
1189        case DIE_MCA_MONARCH_LEAVE:
1190        case DIE_INIT_MONARCH_LEAVE:
1191                xpc_arch_ops.online_heartbeat();
1192                break;
1193        }
1194#else
1195        struct die_args *die_args = _die_args;
1196
1197        switch (event) {
1198        case DIE_TRAP:
1199                if (die_args->trapnr == X86_TRAP_DF)
1200                        xpc_die_deactivate();
1201
1202                if (((die_args->trapnr == X86_TRAP_MF) ||
1203                     (die_args->trapnr == X86_TRAP_XF)) &&
1204                    !user_mode(die_args->regs))
1205                        xpc_die_deactivate();
1206
1207                break;
1208        case DIE_INT3:
1209        case DIE_DEBUG:
1210                break;
1211        case DIE_OOPS:
1212        case DIE_GPF:
1213        default:
1214                xpc_die_deactivate();
1215        }
1216#endif
1217
1218        return NOTIFY_DONE;
1219}
1220
1221static int __init
1222xpc_init(void)
1223{
1224        int ret;
1225        struct task_struct *kthread;
1226
1227        dev_set_name(xpc_part, "part");
1228        dev_set_name(xpc_chan, "chan");
1229
1230        if (is_uv_system()) {
1231                ret = xpc_init_uv();
1232
1233        } else {
1234                ret = -ENODEV;
1235        }
1236
1237        if (ret != 0)
1238                return ret;
1239
1240        ret = xpc_setup_partitions();
1241        if (ret != 0) {
1242                dev_err(xpc_part, "can't get memory for partition structure\n");
1243                goto out_1;
1244        }
1245
1246        xpc_sysctl = register_sysctl_table(xpc_sys_dir);
1247
1248        /*
1249         * Fill the partition reserved page with the information needed by
1250         * other partitions to discover we are alive and establish initial
1251         * communications.
1252         */
1253        ret = xpc_setup_rsvd_page();
1254        if (ret != 0) {
1255                dev_err(xpc_part, "can't setup our reserved page\n");
1256                goto out_2;
1257        }
1258
1259        /* add ourselves to the reboot_notifier_list */
1260        ret = register_reboot_notifier(&xpc_reboot_notifier);
1261        if (ret != 0)
1262                dev_warn(xpc_part, "can't register reboot notifier\n");
1263
1264        /* add ourselves to the die_notifier list */
1265        ret = register_die_notifier(&xpc_die_notifier);
1266        if (ret != 0)
1267                dev_warn(xpc_part, "can't register die notifier\n");
1268
1269        /*
1270         * The real work-horse behind xpc.  This processes incoming
1271         * interrupts and monitors remote heartbeats.
1272         */
1273        kthread = kthread_run(xpc_hb_checker, NULL, XPC_HB_CHECK_THREAD_NAME);
1274        if (IS_ERR(kthread)) {
1275                dev_err(xpc_part, "failed while forking hb check thread\n");
1276                ret = -EBUSY;
1277                goto out_3;
1278        }
1279
1280        /*
1281         * Startup a thread that will attempt to discover other partitions to
1282         * activate based on info provided by SAL. This new thread is short
1283         * lived and will exit once discovery is complete.
1284         */
1285        kthread = kthread_run(xpc_initiate_discovery, NULL,
1286                              XPC_DISCOVERY_THREAD_NAME);
1287        if (IS_ERR(kthread)) {
1288                dev_err(xpc_part, "failed while forking discovery thread\n");
1289
1290                /* mark this new thread as a non-starter */
1291                complete(&xpc_discovery_exited);
1292
1293                xpc_do_exit(xpUnloading);
1294                return -EBUSY;
1295        }
1296
1297        /* set the interface to point at XPC's functions */
1298        xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1299                          xpc_initiate_send, xpc_initiate_send_notify,
1300                          xpc_initiate_received, xpc_initiate_partid_to_nasids);
1301
1302        return 0;
1303
1304        /* initialization was not successful */
1305out_3:
1306        xpc_teardown_rsvd_page();
1307
1308        (void)unregister_die_notifier(&xpc_die_notifier);
1309        (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1310out_2:
1311        if (xpc_sysctl)
1312                unregister_sysctl_table(xpc_sysctl);
1313
1314        xpc_teardown_partitions();
1315out_1:
1316        if (is_uv_system())
1317                xpc_exit_uv();
1318        return ret;
1319}
1320
1321module_init(xpc_init);
1322
1323static void __exit
1324xpc_exit(void)
1325{
1326        xpc_do_exit(xpUnloading);
1327}
1328
1329module_exit(xpc_exit);
1330
1331MODULE_AUTHOR("Silicon Graphics, Inc.");
1332MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1333MODULE_LICENSE("GPL");
1334
1335module_param(xpc_hb_interval, int, 0);
1336MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1337                 "heartbeat increments.");
1338
1339module_param(xpc_hb_check_interval, int, 0);
1340MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1341                 "heartbeat checks.");
1342
1343module_param(xpc_disengage_timelimit, int, 0);
1344MODULE_PARM_DESC(xpc_disengage_timelimit, "Number of seconds to wait "
1345                 "for disengage to complete.");
1346
1347module_param(xpc_kdebug_ignore, int, 0);
1348MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1349                 "other partitions when dropping into kdebug.");
1350