drivers/misc/sgi-xp/xpc_main.c

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