arch/ia64/sn/kernel/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  * Copyright (c) 2004-2006 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   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  *        . We currently have no way to determine which nasid an IPI came
  30  *          from. Thus, xpc_IPI_send() does a remote AMO write followed by
  31  *          an IPI. The AMO indicates where data is to be pulled from, so
  32  *          after the IPI arrives, the remote partition checks the AMO word.
  33  *          The IPI can actually arrive before the AMO however, so other code
  34  *          must periodically check for this case. Also, remote AMO operations
  35  *          do not reliably time out. Thus we do a remote PIO read solely to
  36  *          know whether the remote partition is down and whether we should
  37  *          stop sending IPIs to it. This remote PIO read operation is set up
  38  *          in a special nofault region so SAL knows to ignore (and cleanup)
  39  *          any errors due to the remote AMO write, PIO read, and/or PIO
  40  *          write operations.
  41  *
  42  *          If/when new hardware solves this IPI problem, we should abandon
  43  *          the current approach.
  44  *
  45  */
  46
  47
  48 #include <linux/kernel.h>
  49 #include <linux/module.h>
  50 #include <linux/init.h>
  51 #include <linux/sched.h>
  52 #include <linux/syscalls.h>
  53 #include <linux/cache.h>
  54 #include <linux/interrupt.h>
  55 #include <linux/delay.h>
  56 #include <linux/reboot.h>
  57 #include <linux/completion.h>
  58 #include <asm/sn/intr.h>
  59 #include <asm/sn/sn_sal.h>
  60 #include <asm/kdebug.h>
  61 #include <asm/uaccess.h>
  62 #include <asm/sn/xpc.h>
  63
  64
  65 /* define two XPC debug device structures to be used with dev_dbg() et al */
  66
  67 struct device_driver xpc_dbg_name = {
  68         .name = "xpc"
  69 };
  70
  71 struct device xpc_part_dbg_subname = {
  72         .bus_id = {0},          /* set to "part" at xpc_init() time */
  73         .driver = &xpc_dbg_name
  74 };
  75
  76 struct device xpc_chan_dbg_subname = {
  77         .bus_id = {0},          /* set to "chan" at xpc_init() time */
  78         .driver = &xpc_dbg_name
  79 };
  80
  81 struct device *xpc_part = &xpc_part_dbg_subname;
  82 struct device *xpc_chan = &xpc_chan_dbg_subname;
  83
  84
  85 static int xpc_kdebug_ignore;
  86
  87
  88 /* systune related variables for /proc/sys directories */
  89
  90 static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
  91 static int xpc_hb_min_interval = 1;
  92 static int xpc_hb_max_interval = 10;
  93
  94 static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
  95 static int xpc_hb_check_min_interval = 10;
  96 static int xpc_hb_check_max_interval = 120;
  97
  98 int xpc_disengage_request_timelimit = XPC_DISENGAGE_REQUEST_DEFAULT_TIMELIMIT;
  99 static int xpc_disengage_request_min_timelimit = 0;
 100 static int xpc_disengage_request_max_timelimit = 120;
 101
 102 static ctl_table xpc_sys_xpc_hb_dir[] = {
 103         {
 104                 1,
 105                 "hb_interval",
 106                 &xpc_hb_interval,
 107                 sizeof(int),
 108                 0644,
 109                 NULL,
 110                 &proc_dointvec_minmax,
 111                 NULL,
 112                 &sysctl_intvec,
 113                 NULL,
 114                 &xpc_hb_min_interval,
 115                 &xpc_hb_max_interval
 116         },
 117         {
 118                 2,
 119                 "hb_check_interval",
 120                 &xpc_hb_check_interval,
 121                 sizeof(int),
 122                 0644,
 123                 NULL,
 124                 &proc_dointvec_minmax,
 125                 NULL,
 126                 &sysctl_intvec,
 127                 NULL,
 128                 &xpc_hb_check_min_interval,
 129                 &xpc_hb_check_max_interval
 130         },
 131         {0}
 132 };
 133 static ctl_table xpc_sys_xpc_dir[] = {
 134         {
 135                 1,
 136                 "hb",
 137                 NULL,
 138                 0,
 139                 0555,
 140                 xpc_sys_xpc_hb_dir
 141         },
 142         {
 143                 2,
 144                 "disengage_request_timelimit",
 145                 &xpc_disengage_request_timelimit,
 146                 sizeof(int),
 147                 0644,
 148                 NULL,
 149                 &proc_dointvec_minmax,
 150                 NULL,
 151                 &sysctl_intvec,
 152                 NULL,
 153                 &xpc_disengage_request_min_timelimit,
 154                 &xpc_disengage_request_max_timelimit
 155         },
 156         {0}
 157 };
 158 static ctl_table xpc_sys_dir[] = {
 159         {
 160                 1,
 161                 "xpc",
 162                 NULL,
 163                 0,
 164                 0555,
 165                 xpc_sys_xpc_dir
 166         },
 167         {0}
 168 };
 169 static struct ctl_table_header *xpc_sysctl;
 170
 171 /* non-zero if any remote partition disengage request was timed out */
 172 int xpc_disengage_request_timedout;
 173
 174 /* #of IRQs received */
 175 static atomic_t xpc_act_IRQ_rcvd;
 176
 177 /* IRQ handler notifies this wait queue on receipt of an IRQ */
 178 static DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq);
 179
 180 static unsigned long xpc_hb_check_timeout;
 181
 182 /* notification that the xpc_hb_checker thread has exited */
 183 static DECLARE_COMPLETION(xpc_hb_checker_exited);
 184
 185 /* notification that the xpc_discovery thread has exited */
 186 static DECLARE_COMPLETION(xpc_discovery_exited);
 187
 188
 189 static struct timer_list xpc_hb_timer;
 190
 191
 192 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
 193
 194
 195 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
 196 static struct notifier_block xpc_reboot_notifier = {
 197         .notifier_call = xpc_system_reboot,
 198 };
 199
 200 static int xpc_system_die(struct notifier_block *, unsigned long, void *);
 201 static struct notifier_block xpc_die_notifier = {
 202         .notifier_call = xpc_system_die,
 203 };
 204
 205
 206 /*
 207  * Timer function to enforce the timelimit on the partition disengage request.
 208  */
 209 static void
 210 xpc_timeout_partition_disengage_request(unsigned long data)
 211 {
 212         struct xpc_partition *part = (struct xpc_partition *) data;
 213
 214
 215         DBUG_ON(jiffies < part->disengage_request_timeout);
 216
 217         (void) xpc_partition_disengaged(part);
 218
 219         DBUG_ON(part->disengage_request_timeout != 0);
 220         DBUG_ON(xpc_partition_engaged(1UL << XPC_PARTID(part)) != 0);
 221 }
 222
 223
 224 /*
 225  * Notify the heartbeat check thread that an IRQ has been received.
 226  */
 227 static irqreturn_t
 228 xpc_act_IRQ_handler(int irq, void *dev_id, struct pt_regs *regs)
 229 {
 230         atomic_inc(&xpc_act_IRQ_rcvd);
 231         wake_up_interruptible(&xpc_act_IRQ_wq);
 232         return IRQ_HANDLED;
 233 }
 234
 235
 236 /*
 237  * Timer to produce the heartbeat.  The timer structures function is
 238  * already set when this is initially called.  A tunable is used to
 239  * specify when the next timeout should occur.
 240  */
 241 static void
 242 xpc_hb_beater(unsigned long dummy)
 243 {
 244         xpc_vars->heartbeat++;
 245
 246         if (jiffies >= xpc_hb_check_timeout) {
 247                 wake_up_interruptible(&xpc_act_IRQ_wq);
 248         }
 249
 250         xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
 251         add_timer(&xpc_hb_timer);
 252 }
 253
 254
 255 /*
 256  * This thread is responsible for nearly all of the partition
 257  * activation/deactivation.
 258  */
 259 static int
 260 xpc_hb_checker(void *ignore)
 261 {
 262         int last_IRQ_count = 0;
 263         int new_IRQ_count;
 264         int force_IRQ=0;
 265
 266
 267         /* this thread was marked active by xpc_hb_init() */
 268
 269         daemonize(XPC_HB_CHECK_THREAD_NAME);
 270
 271         set_cpus_allowed(current, cpumask_of_cpu(XPC_HB_CHECK_CPU));
 272
 273         xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
 274
 275         while (!(volatile int) xpc_exiting) {
 276
 277                 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
 278                         "been received\n",
 279                         (int) (xpc_hb_check_timeout - jiffies),
 280                         atomic_read(&xpc_act_IRQ_rcvd) - last_IRQ_count);
 281
 282
 283                 /* checking of remote heartbeats is skewed by IRQ handling */
 284                 if (jiffies >= xpc_hb_check_timeout) {
 285                         dev_dbg(xpc_part, "checking remote heartbeats\n");
 286                         xpc_check_remote_hb();
 287
 288                         /*
 289                          * We need to periodically recheck to ensure no
 290                          * IPI/AMO pairs have been missed.  That check
 291                          * must always reset xpc_hb_check_timeout.
 292                          */
 293                         force_IRQ = 1;
 294                 }
 295
 296
 297                 /* check for outstanding IRQs */
 298                 new_IRQ_count = atomic_read(&xpc_act_IRQ_rcvd);
 299                 if (last_IRQ_count < new_IRQ_count || force_IRQ != 0) {
 300                         force_IRQ = 0;
 301
 302                         dev_dbg(xpc_part, "found an IRQ to process; will be "
 303                                 "resetting xpc_hb_check_timeout\n");
 304
 305                         last_IRQ_count += xpc_identify_act_IRQ_sender();
 306                         if (last_IRQ_count < new_IRQ_count) {
 307                                 /* retry once to help avoid missing AMO */
 308                                 (void) xpc_identify_act_IRQ_sender();
 309                         }
 310                         last_IRQ_count = new_IRQ_count;
 311
 312                         xpc_hb_check_timeout = jiffies +
 313                                            (xpc_hb_check_interval * HZ);
 314                 }
 315
 316                 /* wait for IRQ or timeout */
 317                 (void) wait_event_interruptible(xpc_act_IRQ_wq,
 318                             (last_IRQ_count < atomic_read(&xpc_act_IRQ_rcvd) ||
 319                                         jiffies >= xpc_hb_check_timeout ||
 320                                                 (volatile int) xpc_exiting));
 321         }
 322
 323         dev_dbg(xpc_part, "heartbeat checker is exiting\n");
 324
 325
 326         /* mark this thread as having exited */
 327         complete(&xpc_hb_checker_exited);
 328         return 0;
 329 }
 330
 331
 332 /*
 333  * This thread will attempt to discover other partitions to activate
 334  * based on info provided by SAL. This new thread is short lived and
 335  * will exit once discovery is complete.
 336  */
 337 static int
 338 xpc_initiate_discovery(void *ignore)
 339 {
 340         daemonize(XPC_DISCOVERY_THREAD_NAME);
 341
 342         xpc_discovery();
 343
 344         dev_dbg(xpc_part, "discovery thread is exiting\n");
 345
 346         /* mark this thread as having exited */
 347         complete(&xpc_discovery_exited);
 348         return 0;
 349 }
 350
 351
 352 /*
 353  * Establish first contact with the remote partititon. This involves pulling
 354  * the XPC per partition variables from the remote partition and waiting for
 355  * the remote partition to pull ours.
 356  */
 357 static enum xpc_retval
 358 xpc_make_first_contact(struct xpc_partition *part)
 359 {
 360         enum xpc_retval ret;
 361
 362
 363         while ((ret = xpc_pull_remote_vars_part(part)) != xpcSuccess) {
 364                 if (ret != xpcRetry) {
 365                         XPC_DEACTIVATE_PARTITION(part, ret);
 366                         return ret;
 367                 }
 368
 369                 dev_dbg(xpc_chan, "waiting to make first contact with "
 370                         "partition %d\n", XPC_PARTID(part));
 371
 372                 /* wait a 1/4 of a second or so */
 373                 (void) msleep_interruptible(250);
 374
 375                 if (part->act_state == XPC_P_DEACTIVATING) {
 376                         return part->reason;
 377                 }
 378         }
 379
 380         return xpc_mark_partition_active(part);
 381 }
 382
 383
 384 /*
 385  * The first kthread assigned to a newly activated partition is the one
 386  * created by XPC HB with which it calls xpc_partition_up(). XPC hangs on to
 387  * that kthread until the partition is brought down, at which time that kthread
 388  * returns back to XPC HB. (The return of that kthread will signify to XPC HB
 389  * that XPC has dismantled all communication infrastructure for the associated
 390  * partition.) This kthread becomes the channel manager for that partition.
 391  *
 392  * Each active partition has a channel manager, who, besides connecting and
 393  * disconnecting channels, will ensure that each of the partition's connected
 394  * channels has the required number of assigned kthreads to get the work done.
 395  */
 396 static void
 397 xpc_channel_mgr(struct xpc_partition *part)
 398 {
 399         while (part->act_state != XPC_P_DEACTIVATING ||
 400                         atomic_read(&part->nchannels_active) > 0 ||
 401                                         !xpc_partition_disengaged(part)) {
 402
 403                 xpc_process_channel_activity(part);
 404
 405
 406                 /*
 407                  * Wait until we've been requested to activate kthreads or
 408                  * all of the channel's message queues have been torn down or
 409                  * a signal is pending.
 410                  *
 411                  * The channel_mgr_requests is set to 1 after being awakened,
 412                  * This is done to prevent the channel mgr from making one pass
 413                  * through the loop for each request, since he will
 414                  * be servicing all the requests in one pass. The reason it's
 415                  * set to 1 instead of 0 is so that other kthreads will know
 416                  * that the channel mgr is running and won't bother trying to
 417                  * wake him up.
 418                  */
 419                 atomic_dec(&part->channel_mgr_requests);
 420                 (void) wait_event_interruptible(part->channel_mgr_wq,
 421                                 (atomic_read(&part->channel_mgr_requests) > 0 ||
 422                                 (volatile u64) part->local_IPI_amo != 0 ||
 423                                 ((volatile u8) part->act_state ==
 424                                                         XPC_P_DEACTIVATING &&
 425                                 atomic_read(&part->nchannels_active) == 0 &&
 426                                 xpc_partition_disengaged(part))));
 427                 atomic_set(&part->channel_mgr_requests, 1);
 428
 429                 // >>> Does it need to wakeup periodically as well? In case we
 430                 // >>> miscalculated the #of kthreads to wakeup or create?
 431         }
 432 }
 433
 434
 435 /*
 436  * When XPC HB determines that a partition has come up, it will create a new
 437  * kthread and that kthread will call this function to attempt to set up the
 438  * basic infrastructure used for Cross Partition Communication with the newly
 439  * upped partition.
 440  *
 441  * The kthread that was created by XPC HB and which setup the XPC
 442  * infrastructure will remain assigned to the partition until the partition
 443  * goes down. At which time the kthread will teardown the XPC infrastructure
 444  * and then exit.
 445  *
 446  * XPC HB will put the remote partition's XPC per partition specific variables
 447  * physical address into xpc_partitions[partid].remote_vars_part_pa prior to
 448  * calling xpc_partition_up().
 449  */
 450 static void
 451 xpc_partition_up(struct xpc_partition *part)
 452 {
 453         DBUG_ON(part->channels != NULL);
 454
 455         dev_dbg(xpc_chan, "activating partition %d\n", XPC_PARTID(part));
 456
 457         if (xpc_setup_infrastructure(part) != xpcSuccess) {
 458                 return;
 459         }
 460
 461         /*
 462          * The kthread that XPC HB called us with will become the
 463          * channel manager for this partition. It will not return
 464          * back to XPC HB until the partition's XPC infrastructure
 465          * has been dismantled.
 466          */
 467
 468         (void) xpc_part_ref(part);      /* this will always succeed */
 469
 470         if (xpc_make_first_contact(part) == xpcSuccess) {
 471                 xpc_channel_mgr(part);
 472         }
 473
 474         xpc_part_deref(part);
 475
 476         xpc_teardown_infrastructure(part);
 477 }
 478
 479
 480 static int
 481 xpc_activating(void *__partid)
 482 {
 483         partid_t partid = (u64) __partid;
 484         struct xpc_partition *part = &xpc_partitions[partid];
 485         unsigned long irq_flags;
 486         struct sched_param param = { sched_priority: MAX_RT_PRIO - 1 };
 487         int ret;
 488
 489
 490         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
 491
 492         spin_lock_irqsave(&part->act_lock, irq_flags);
 493
 494         if (part->act_state == XPC_P_DEACTIVATING) {
 495                 part->act_state = XPC_P_INACTIVE;
 496                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 497                 part->remote_rp_pa = 0;
 498                 return 0;
 499         }
 500
 501         /* indicate the thread is activating */
 502         DBUG_ON(part->act_state != XPC_P_ACTIVATION_REQ);
 503         part->act_state = XPC_P_ACTIVATING;
 504
 505         XPC_SET_REASON(part, 0, 0);
 506         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 507
 508         dev_dbg(xpc_part, "bringing partition %d up\n", partid);
 509
 510         daemonize("xpc%02d", partid);
 511
 512         /*
 513          * This thread needs to run at a realtime priority to prevent a
 514          * significant performance degradation.
 515          */
 516         ret = sched_setscheduler(current, SCHED_FIFO, &param);
 517         if (ret != 0) {
 518                 dev_warn(xpc_part, "unable to set pid %d to a realtime "
 519                         "priority, ret=%d\n", current->pid, ret);
 520         }
 521
 522         /* allow this thread and its children to run on any CPU */
 523         set_cpus_allowed(current, CPU_MASK_ALL);
 524
 525         /*
 526          * Register the remote partition's AMOs with SAL so it can handle
 527          * and cleanup errors within that address range should the remote
 528          * partition go down. We don't unregister this range because it is
 529          * difficult to tell when outstanding writes to the remote partition
 530          * are finished and thus when it is safe to unregister. This should
 531          * not result in wasted space in the SAL xp_addr_region table because
 532          * we should get the same page for remote_amos_page_pa after module
 533          * reloads and system reboots.
 534          */
 535         if (sn_register_xp_addr_region(part->remote_amos_page_pa,
 536                                                         PAGE_SIZE, 1) < 0) {
 537                 dev_warn(xpc_part, "xpc_partition_up(%d) failed to register "
 538                         "xp_addr region\n", partid);
 539
 540                 spin_lock_irqsave(&part->act_lock, irq_flags);
 541                 part->act_state = XPC_P_INACTIVE;
 542                 XPC_SET_REASON(part, xpcPhysAddrRegFailed, __LINE__);
 543                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 544                 part->remote_rp_pa = 0;
 545                 return 0;
 546         }
 547
 548         xpc_allow_hb(partid, xpc_vars);
 549         xpc_IPI_send_activated(part);
 550
 551
 552         /*
 553          * xpc_partition_up() holds this thread and marks this partition as
 554          * XPC_P_ACTIVE by calling xpc_hb_mark_active().
 555          */
 556         (void) xpc_partition_up(part);
 557
 558         xpc_disallow_hb(partid, xpc_vars);
 559         xpc_mark_partition_inactive(part);
 560
 561         if (part->reason == xpcReactivating) {
 562                 /* interrupting ourselves results in activating partition */
 563                 xpc_IPI_send_reactivate(part);
 564         }
 565
 566         return 0;
 567 }
 568
 569
 570 void
 571 xpc_activate_partition(struct xpc_partition *part)
 572 {
 573         partid_t partid = XPC_PARTID(part);
 574         unsigned long irq_flags;
 575         pid_t pid;
 576
 577
 578         spin_lock_irqsave(&part->act_lock, irq_flags);
 579
 580         DBUG_ON(part->act_state != XPC_P_INACTIVE);
 581
 582         part->act_state = XPC_P_ACTIVATION_REQ;
 583         XPC_SET_REASON(part, xpcCloneKThread, __LINE__);
 584
 585         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 586
 587         pid = kernel_thread(xpc_activating, (void *) ((u64) partid), 0);
 588
 589         if (unlikely(pid <= 0)) {
 590                 spin_lock_irqsave(&part->act_lock, irq_flags);
 591                 part->act_state = XPC_P_INACTIVE;
 592                 XPC_SET_REASON(part, xpcCloneKThreadFailed, __LINE__);
 593                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 594         }
 595 }
 596
 597
 598 /*
 599  * Handle the receipt of a SGI_XPC_NOTIFY IRQ by seeing whether the specified
 600  * partition actually sent it. Since SGI_XPC_NOTIFY IRQs may be shared by more
 601  * than one partition, we use an AMO_t structure per partition to indicate
 602  * whether a partition has sent an IPI or not.  >>> If it has, then wake up the
 603  * associated kthread to handle it.
 604  *
 605  * All SGI_XPC_NOTIFY IRQs received by XPC are the result of IPIs sent by XPC
 606  * running on other partitions.
 607  *
 608  * Noteworthy Arguments:
 609  *
 610  *      irq - Interrupt ReQuest number. NOT USED.
 611  *
 612  *      dev_id - partid of IPI's potential sender.
 613  *
 614  *      regs - processor's context before the processor entered
 615  *             interrupt code. NOT USED.
 616  */
 617 irqreturn_t
 618 xpc_notify_IRQ_handler(int irq, void *dev_id, struct pt_regs *regs)
 619 {
 620         partid_t partid = (partid_t) (u64) dev_id;
 621         struct xpc_partition *part = &xpc_partitions[partid];
 622
 623
 624         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
 625
 626         if (xpc_part_ref(part)) {
 627                 xpc_check_for_channel_activity(part);
 628
 629                 xpc_part_deref(part);
 630         }
 631         return IRQ_HANDLED;
 632 }
 633
 634
 635 /*
 636  * Check to see if xpc_notify_IRQ_handler() dropped any IPIs on the floor
 637  * because the write to their associated IPI amo completed after the IRQ/IPI
 638  * was received.
 639  */
 640 void
 641 xpc_dropped_IPI_check(struct xpc_partition *part)
 642 {
 643         if (xpc_part_ref(part)) {
 644                 xpc_check_for_channel_activity(part);
 645
 646                 part->dropped_IPI_timer.expires = jiffies +
 647                                                         XPC_P_DROPPED_IPI_WAIT;
 648                 add_timer(&part->dropped_IPI_timer);
 649                 xpc_part_deref(part);
 650         }
 651 }
 652
 653
 654 void
 655 xpc_activate_kthreads(struct xpc_channel *ch, int needed)
 656 {
 657         int idle = atomic_read(&ch->kthreads_idle);
 658         int assigned = atomic_read(&ch->kthreads_assigned);
 659         int wakeup;
 660
 661
 662         DBUG_ON(needed <= 0);
 663
 664         if (idle > 0) {
 665                 wakeup = (needed > idle) ? idle : needed;
 666                 needed -= wakeup;
 667
 668                 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
 669                         "channel=%d\n", wakeup, ch->partid, ch->number);
 670
 671                 /* only wakeup the requested number of kthreads */
 672                 wake_up_nr(&ch->idle_wq, wakeup);
 673         }
 674
 675         if (needed <= 0) {
 676                 return;
 677         }
 678
 679         if (needed + assigned > ch->kthreads_assigned_limit) {
 680                 needed = ch->kthreads_assigned_limit - assigned;
 681                 // >>>should never be less than 0
 682                 if (needed <= 0) {
 683                         return;
 684                 }
 685         }
 686
 687         dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
 688                 needed, ch->partid, ch->number);
 689
 690         xpc_create_kthreads(ch, needed);
 691 }
 692
 693
 694 /*
 695  * This function is where XPC's kthreads wait for messages to deliver.
 696  */
 697 static void
 698 xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
 699 {
 700         do {
 701                 /* deliver messages to their intended recipients */
 702
 703                 while ((volatile s64) ch->w_local_GP.get <
 704                                 (volatile s64) ch->w_remote_GP.put &&
 705                                         !((volatile u32) ch->flags &
 706                                                 XPC_C_DISCONNECTING)) {
 707                         xpc_deliver_msg(ch);
 708                 }
 709
 710                 if (atomic_inc_return(&ch->kthreads_idle) >
 711                                                 ch->kthreads_idle_limit) {
 712                         /* too many idle kthreads on this channel */
 713                         atomic_dec(&ch->kthreads_idle);
 714                         break;
 715                 }
 716
 717                 dev_dbg(xpc_chan, "idle kthread calling "
 718                         "wait_event_interruptible_exclusive()\n");
 719
 720                 (void) wait_event_interruptible_exclusive(ch->idle_wq,
 721                                 ((volatile s64) ch->w_local_GP.get <
 722                                         (volatile s64) ch->w_remote_GP.put ||
 723                                 ((volatile u32) ch->flags &
 724                                                 XPC_C_DISCONNECTING)));
 725
 726                 atomic_dec(&ch->kthreads_idle);
 727
 728         } while (!((volatile u32) ch->flags & XPC_C_DISCONNECTING));
 729 }
 730
 731
 732 static int
 733 xpc_daemonize_kthread(void *args)
 734 {
 735         partid_t partid = XPC_UNPACK_ARG1(args);
 736         u16 ch_number = XPC_UNPACK_ARG2(args);
 737         struct xpc_partition *part = &xpc_partitions[partid];
 738         struct xpc_channel *ch;
 739         int n_needed;
 740         unsigned long irq_flags;
 741
 742
 743         daemonize("xpc%02dc%d", partid, ch_number);
 744
 745         dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
 746                 partid, ch_number);
 747
 748         ch = &part->channels[ch_number];
 749
 750         if (!(ch->flags & XPC_C_DISCONNECTING)) {
 751
 752                 /* let registerer know that connection has been established */
 753
 754                 spin_lock_irqsave(&ch->lock, irq_flags);
 755                 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
 756                         ch->flags |= XPC_C_CONNECTEDCALLOUT;
 757                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 758
 759                         xpc_connected_callout(ch);
 760
 761                         spin_lock_irqsave(&ch->lock, irq_flags);
 762                         ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
 763                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 764
 765                         /*
 766                          * It is possible that while the callout was being
 767                          * made that the remote partition sent some messages.
 768                          * If that is the case, we may need to activate
 769                          * additional kthreads to help deliver them. We only
 770                          * need one less than total #of messages to deliver.
 771                          */
 772                         n_needed = ch->w_remote_GP.put - ch->w_local_GP.get - 1;
 773                         if (n_needed > 0 &&
 774                                         !(ch->flags & XPC_C_DISCONNECTING)) {
 775                                 xpc_activate_kthreads(ch, n_needed);
 776                         }
 777                 } else {
 778                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 779                 }
 780
 781                 xpc_kthread_waitmsgs(part, ch);
 782         }
 783
 784         if (atomic_dec_return(&ch->kthreads_assigned) == 0) {
 785                 spin_lock_irqsave(&ch->lock, irq_flags);
 786                 if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
 787                                 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
 788                         ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
 789                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 790
 791                         xpc_disconnect_callout(ch, xpcDisconnecting);
 792
 793                         spin_lock_irqsave(&ch->lock, irq_flags);
 794                         ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
 795                 }
 796                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 797                 if (atomic_dec_return(&part->nchannels_engaged) == 0) {
 798                         xpc_mark_partition_disengaged(part);
 799                         xpc_IPI_send_disengage(part);
 800                 }
 801         }
 802
 803
 804         xpc_msgqueue_deref(ch);
 805
 806         dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
 807                 partid, ch_number);
 808
 809         xpc_part_deref(part);
 810         return 0;
 811 }
 812
 813
 814 /*
 815  * For each partition that XPC has established communications with, there is
 816  * a minimum of one kernel thread assigned to perform any operation that
 817  * may potentially sleep or block (basically the callouts to the asynchronous
 818  * functions registered via xpc_connect()).
 819  *
 820  * Additional kthreads are created and destroyed by XPC as the workload
 821  * demands.
 822  *
 823  * A kthread is assigned to one of the active channels that exists for a given
 824  * partition.
 825  */
 826 void
 827 xpc_create_kthreads(struct xpc_channel *ch, int needed)
 828 {
 829         unsigned long irq_flags;
 830         pid_t pid;
 831         u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
 832         struct xpc_partition *part = &xpc_partitions[ch->partid];
 833
 834
 835         while (needed-- > 0) {
 836
 837                 /*
 838                  * The following is done on behalf of the newly created
 839                  * kthread. That kthread is responsible for doing the
 840                  * counterpart to the following before it exits.
 841                  */
 842                 (void) xpc_part_ref(part);
 843                 xpc_msgqueue_ref(ch);
 844                 if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
 845                     atomic_inc_return(&part->nchannels_engaged) == 1) {
 846                         xpc_mark_partition_engaged(part);
 847                 }
 848
 849                 pid = kernel_thread(xpc_daemonize_kthread, (void *) args, 0);
 850                 if (pid < 0) {
 851                         /* the fork failed */
 852                         if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 853                             atomic_dec_return(&part->nchannels_engaged) == 0) {
 854                                 xpc_mark_partition_disengaged(part);
 855                                 xpc_IPI_send_disengage(part);
 856                         }
 857                         xpc_msgqueue_deref(ch);
 858                         xpc_part_deref(part);
 859
 860                         if (atomic_read(&ch->kthreads_assigned) <
 861                                                 ch->kthreads_idle_limit) {
 862                                 /*
 863                                  * Flag this as an error only if we have an
 864                                  * insufficient #of kthreads for the channel
 865                                  * to function.
 866                                  *
 867                                  * No xpc_msgqueue_ref() is needed here since
 868                                  * the channel mgr is doing this.
 869                                  */
 870                                 spin_lock_irqsave(&ch->lock, irq_flags);
 871                                 XPC_DISCONNECT_CHANNEL(ch, xpcLackOfResources,
 872                                                                 &irq_flags);
 873                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 874                         }
 875                         break;
 876                 }
 877
 878                 ch->kthreads_created++; // >>> temporary debug only!!!
 879         }
 880 }
 881
 882
 883 void
 884 xpc_disconnect_wait(int ch_number)
 885 {
 886         unsigned long irq_flags;
 887         partid_t partid;
 888         struct xpc_partition *part;
 889         struct xpc_channel *ch;
 890         int wakeup_channel_mgr;
 891
 892
 893         /* now wait for all callouts to the caller's function to cease */
 894         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
 895                 part = &xpc_partitions[partid];
 896
 897                 if (!xpc_part_ref(part)) {
 898                         continue;
 899                 }
 900
 901                 ch = &part->channels[ch_number];
 902
 903                 if (!(ch->flags & XPC_C_WDISCONNECT)) {
 904                         xpc_part_deref(part);
 905                         continue;
 906                 }
 907
 908                 wait_for_completion(&ch->wdisconnect_wait);
 909
 910                 spin_lock_irqsave(&ch->lock, irq_flags);
 911                 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
 912                 wakeup_channel_mgr = 0;
 913
 914                 if (ch->delayed_IPI_flags) {
 915                         if (part->act_state != XPC_P_DEACTIVATING) {
 916                                 spin_lock(&part->IPI_lock);
 917                                 XPC_SET_IPI_FLAGS(part->local_IPI_amo,
 918                                         ch->number, ch->delayed_IPI_flags);
 919                                 spin_unlock(&part->IPI_lock);
 920                                 wakeup_channel_mgr = 1;
 921                         }
 922                         ch->delayed_IPI_flags = 0;
 923                 }
 924
 925                 ch->flags &= ~XPC_C_WDISCONNECT;
 926                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 927
 928                 if (wakeup_channel_mgr) {
 929                         xpc_wakeup_channel_mgr(part);
 930                 }
 931
 932                 xpc_part_deref(part);
 933         }
 934 }
 935
 936
 937 static void
 938 xpc_do_exit(enum xpc_retval reason)
 939 {
 940         partid_t partid;
 941         int active_part_count, printed_waiting_msg = 0;
 942         struct xpc_partition *part;
 943         unsigned long printmsg_time, disengage_request_timeout = 0;
 944
 945
 946         /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
 947         DBUG_ON(xpc_exiting == 1);
 948
 949         /*
 950          * Let the heartbeat checker thread and the discovery thread
 951          * (if one is running) know that they should exit. Also wake up
 952          * the heartbeat checker thread in case it's sleeping.
 953          */
 954         xpc_exiting = 1;
 955         wake_up_interruptible(&xpc_act_IRQ_wq);
 956
 957         /* ignore all incoming interrupts */
 958         free_irq(SGI_XPC_ACTIVATE, NULL);
 959
 960         /* wait for the discovery thread to exit */
 961         wait_for_completion(&xpc_discovery_exited);
 962
 963         /* wait for the heartbeat checker thread to exit */
 964         wait_for_completion(&xpc_hb_checker_exited);
 965
 966
 967         /* sleep for a 1/3 of a second or so */
 968         (void) msleep_interruptible(300);
 969
 970
 971         /* wait for all partitions to become inactive */
 972
 973         printmsg_time = jiffies + (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
 974         xpc_disengage_request_timedout = 0;
 975
 976         do {
 977                 active_part_count = 0;
 978
 979                 for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
 980                         part = &xpc_partitions[partid];
 981
 982                         if (xpc_partition_disengaged(part) &&
 983                                         part->act_state == XPC_P_INACTIVE) {
 984                                 continue;
 985                         }
 986
 987                         active_part_count++;
 988
 989                         XPC_DEACTIVATE_PARTITION(part, reason);
 990
 991                         if (part->disengage_request_timeout >
 992                                                 disengage_request_timeout) {
 993                                 disengage_request_timeout =
 994                                                 part->disengage_request_timeout;
 995                         }
 996                 }
 997
 998                 if (xpc_partition_engaged(-1UL)) {
 999                         if (time_after(jiffies, printmsg_time)) {
1000                                 dev_info(xpc_part, "waiting for remote "
1001                                         "partitions to disengage, timeout in "
1002                                         "%ld seconds\n",
1003                                         (disengage_request_timeout - jiffies)
1004                                                                         / HZ);
1005                                 printmsg_time = jiffies +
1006                                         (XPC_DISENGAGE_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 disengage\n");
1014                                 printed_waiting_msg = 0;
1015                         }
1016
1017                 } else {
1018                         if (!xpc_disengage_request_timedout) {
1019                                 dev_info(xpc_part, "all partitions have "
1020                                         "disengaged\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_partition_engaged(-1UL));
1031
1032
1033         /* indicate to others that our reserved page is uninitialized */
1034         xpc_rsvd_page->vars_pa = 0;
1035
1036         /* now it's time to eliminate our heartbeat */
1037         del_timer_sync(&xpc_hb_timer);
1038         DBUG_ON(xpc_vars->heartbeating_to_mask != 0);
1039
1040         if (reason == xpcUnloading) {
1041                 /* take ourselves off of the reboot_notifier_list */
1042                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1043
1044                 /* take ourselves off of the die_notifier list */
1045                 (void) unregister_die_notifier(&xpc_die_notifier);
1046         }
1047
1048         /* close down protections for IPI operations */
1049         xpc_restrict_IPI_ops();
1050
1051
1052         /* clear the interface to XPC's functions */
1053         xpc_clear_interface();
1054
1055         if (xpc_sysctl) {
1056                 unregister_sysctl_table(xpc_sysctl);
1057         }
1058 }
1059
1060
1061 /*
1062  * This function is called when the system is being rebooted.
1063  */
1064 static int
1065 xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1066 {
1067         enum xpc_retval reason;
1068
1069
1070         switch (event) {
1071         case SYS_RESTART:
1072                 reason = xpcSystemReboot;
1073                 break;
1074         case SYS_HALT:
1075                 reason = xpcSystemHalt;
1076                 break;
1077         case SYS_POWER_OFF:
1078                 reason = xpcSystemPoweroff;
1079                 break;
1080         default:
1081                 reason = xpcSystemGoingDown;
1082         }
1083
1084         xpc_do_exit(reason);
1085         return NOTIFY_DONE;
1086 }
1087
1088
1089 /*
1090  * Notify other partitions to disengage from all references to our memory.
1091  */
1092 static void
1093 xpc_die_disengage(void)
1094 {
1095         struct xpc_partition *part;
1096         partid_t partid;
1097         unsigned long engaged;
1098         long time, printmsg_time, disengage_request_timeout;
1099
1100
1101         /* keep xpc_hb_checker thread from doing anything (just in case) */
1102         xpc_exiting = 1;
1103
1104         xpc_vars->heartbeating_to_mask = 0;  /* indicate we're deactivated */
1105
1106         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1107                 part = &xpc_partitions[partid];
1108
1109                 if (!XPC_SUPPORTS_DISENGAGE_REQUEST(part->
1110                                                         remote_vars_version)) {
1111
1112                         /* just in case it was left set by an earlier XPC */
1113                         xpc_clear_partition_engaged(1UL << partid);
1114                         continue;
1115                 }
1116
1117                 if (xpc_partition_engaged(1UL << partid) ||
1118                                         part->act_state != XPC_P_INACTIVE) {
1119                         xpc_request_partition_disengage(part);
1120                         xpc_mark_partition_disengaged(part);
1121                         xpc_IPI_send_disengage(part);
1122                 }
1123         }
1124
1125         time = rtc_time();
1126         printmsg_time = time +
1127                 (XPC_DISENGAGE_PRINTMSG_INTERVAL * sn_rtc_cycles_per_second);
1128         disengage_request_timeout = time +
1129                 (xpc_disengage_request_timelimit * sn_rtc_cycles_per_second);
1130
1131         /* wait for all other partitions to disengage from us */
1132
1133         while (1) {
1134                 engaged = xpc_partition_engaged(-1UL);
1135                 if (!engaged) {
1136                         dev_info(xpc_part, "all partitions have disengaged\n");
1137                         break;
1138                 }
1139
1140                 time = rtc_time();
1141                 if (time >= disengage_request_timeout) {
1142                         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1143                                 if (engaged & (1UL << partid)) {
1144                                         dev_info(xpc_part, "disengage from "
1145                                                 "remote partition %d timed "
1146                                                 "out\n", partid);
1147                                 }
1148                         }
1149                         break;
1150                 }
1151
1152                 if (time >= printmsg_time) {
1153                         dev_info(xpc_part, "waiting for remote partitions to "
1154                                 "disengage, timeout in %ld seconds\n",
1155                                 (disengage_request_timeout - time) /
1156                                                 sn_rtc_cycles_per_second);
1157                         printmsg_time = time +
1158                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL *
1159                                                 sn_rtc_cycles_per_second);
1160                 }
1161         }
1162 }
1163
1164
1165 /*
1166  * This function is called when the system is being restarted or halted due
1167  * to some sort of system failure. If this is the case we need to notify the
1168  * other partitions to disengage from all references to our memory.
1169  * This function can also be called when our heartbeater could be offlined
1170  * for a time. In this case we need to notify other partitions to not worry
1171  * about the lack of a heartbeat.
1172  */
1173 static int
1174 xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1175 {
1176         switch (event) {
1177         case DIE_MACHINE_RESTART:
1178         case DIE_MACHINE_HALT:
1179                 xpc_die_disengage();
1180                 break;
1181
1182         case DIE_KDEBUG_ENTER:
1183                 /* Should lack of heartbeat be ignored by other partitions? */
1184                 if (!xpc_kdebug_ignore) {
1185                         break;
1186                 }
1187                 /* fall through */
1188         case DIE_MCA_MONARCH_ENTER:
1189         case DIE_INIT_MONARCH_ENTER:
1190                 xpc_vars->heartbeat++;
1191                 xpc_vars->heartbeat_offline = 1;
1192                 break;
1193
1194         case DIE_KDEBUG_LEAVE:
1195                 /* Is lack of heartbeat being ignored by other partitions? */
1196                 if (!xpc_kdebug_ignore) {
1197                         break;
1198                 }
1199                 /* fall through */
1200         case DIE_MCA_MONARCH_LEAVE:
1201         case DIE_INIT_MONARCH_LEAVE:
1202                 xpc_vars->heartbeat++;
1203                 xpc_vars->heartbeat_offline = 0;
1204                 break;
1205         }
1206
1207         return NOTIFY_DONE;
1208 }
1209
1210
1211 int __init
1212 xpc_init(void)
1213 {
1214         int ret;
1215         partid_t partid;
1216         struct xpc_partition *part;
1217         pid_t pid;
1218
1219
1220         if (!ia64_platform_is("sn2")) {
1221                 return -ENODEV;
1222         }
1223
1224         /*
1225          * xpc_remote_copy_buffer is used as a temporary buffer for bte_copy'ng
1226          * various portions of a partition's reserved page. Its size is based
1227          * on the size of the reserved page header and part_nasids mask. So we
1228          * need to ensure that the other items will fit as well.
1229          */
1230         if (XPC_RP_VARS_SIZE > XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES) {
1231                 dev_err(xpc_part, "xpc_remote_copy_buffer is not big enough\n");
1232                 return -EPERM;
1233         }
1234         DBUG_ON((u64) xpc_remote_copy_buffer !=
1235                                 L1_CACHE_ALIGN((u64) xpc_remote_copy_buffer));
1236
1237         snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
1238         snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
1239
1240         xpc_sysctl = register_sysctl_table(xpc_sys_dir, 1);
1241
1242         /*
1243          * The first few fields of each entry of xpc_partitions[] need to
1244          * be initialized now so that calls to xpc_connect() and
1245          * xpc_disconnect() can be made prior to the activation of any remote
1246          * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
1247          * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
1248          * PARTITION HAS BEEN ACTIVATED.
1249          */
1250         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1251                 part = &xpc_partitions[partid];
1252
1253                 DBUG_ON((u64) part != L1_CACHE_ALIGN((u64) part));
1254
1255                 part->act_IRQ_rcvd = 0;
1256                 spin_lock_init(&part->act_lock);
1257                 part->act_state = XPC_P_INACTIVE;
1258                 XPC_SET_REASON(part, 0, 0);
1259
1260                 init_timer(&part->disengage_request_timer);
1261                 part->disengage_request_timer.function =
1262                                 xpc_timeout_partition_disengage_request;
1263                 part->disengage_request_timer.data = (unsigned long) part;
1264
1265                 part->setup_state = XPC_P_UNSET;
1266                 init_waitqueue_head(&part->teardown_wq);
1267                 atomic_set(&part->references, 0);
1268         }
1269
1270         /*
1271          * Open up protections for IPI operations (and AMO operations on
1272          * Shub 1.1 systems).
1273          */
1274         xpc_allow_IPI_ops();
1275
1276         /*
1277          * Interrupts being processed will increment this atomic variable and
1278          * awaken the heartbeat thread which will process the interrupts.
1279          */
1280         atomic_set(&xpc_act_IRQ_rcvd, 0);
1281
1282         /*
1283          * This is safe to do before the xpc_hb_checker thread has started
1284          * because the handler releases a wait queue.  If an interrupt is
1285          * received before the thread is waiting, it will not go to sleep,
1286          * but rather immediately process the interrupt.
1287          */
1288         ret = request_irq(SGI_XPC_ACTIVATE, xpc_act_IRQ_handler, 0,
1289                                                         "xpc hb", NULL);
1290         if (ret != 0) {
1291                 dev_err(xpc_part, "can't register ACTIVATE IRQ handler, "
1292                         "errno=%d\n", -ret);
1293
1294                 xpc_restrict_IPI_ops();
1295
1296                 if (xpc_sysctl) {
1297                         unregister_sysctl_table(xpc_sysctl);
1298                 }
1299                 return -EBUSY;
1300         }
1301
1302         /*
1303          * Fill the partition reserved page with the information needed by
1304          * other partitions to discover we are alive and establish initial
1305          * communications.
1306          */
1307         xpc_rsvd_page = xpc_rsvd_page_init();
1308         if (xpc_rsvd_page == NULL) {
1309                 dev_err(xpc_part, "could not setup our reserved page\n");
1310
1311                 free_irq(SGI_XPC_ACTIVATE, NULL);
1312                 xpc_restrict_IPI_ops();
1313
1314                 if (xpc_sysctl) {
1315                         unregister_sysctl_table(xpc_sysctl);
1316                 }
1317                 return -EBUSY;
1318         }
1319
1320
1321         /* add ourselves to the reboot_notifier_list */
1322         ret = register_reboot_notifier(&xpc_reboot_notifier);
1323         if (ret != 0) {
1324                 dev_warn(xpc_part, "can't register reboot notifier\n");
1325         }
1326
1327         /* add ourselves to the die_notifier list (i.e., ia64die_chain) */
1328         ret = register_die_notifier(&xpc_die_notifier);
1329         if (ret != 0) {
1330                 dev_warn(xpc_part, "can't register die notifier\n");
1331         }
1332
1333
1334         /*
1335          * Set the beating to other partitions into motion.  This is
1336          * the last requirement for other partitions' discovery to
1337          * initiate communications with us.
1338          */
1339         init_timer(&xpc_hb_timer);
1340         xpc_hb_timer.function = xpc_hb_beater;
1341         xpc_hb_beater(0);
1342
1343
1344         /*
1345          * The real work-horse behind xpc.  This processes incoming
1346          * interrupts and monitors remote heartbeats.
1347          */
1348         pid = kernel_thread(xpc_hb_checker, NULL, 0);
1349         if (pid < 0) {
1350                 dev_err(xpc_part, "failed while forking hb check thread\n");
1351
1352                 /* indicate to others that our reserved page is uninitialized */
1353                 xpc_rsvd_page->vars_pa = 0;
1354
1355                 /* take ourselves off of the reboot_notifier_list */
1356                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1357
1358                 /* take ourselves off of the die_notifier list */
1359                 (void) unregister_die_notifier(&xpc_die_notifier);
1360
1361                 del_timer_sync(&xpc_hb_timer);
1362                 free_irq(SGI_XPC_ACTIVATE, NULL);
1363                 xpc_restrict_IPI_ops();
1364
1365                 if (xpc_sysctl) {
1366                         unregister_sysctl_table(xpc_sysctl);
1367                 }
1368                 return -EBUSY;
1369         }
1370
1371
1372         /*
1373          * Startup a thread that will attempt to discover other partitions to
1374          * activate based on info provided by SAL. This new thread is short
1375          * lived and will exit once discovery is complete.
1376          */
1377         pid = kernel_thread(xpc_initiate_discovery, NULL, 0);
1378         if (pid < 0) {
1379                 dev_err(xpc_part, "failed while forking discovery thread\n");
1380
1381                 /* mark this new thread as a non-starter */
1382                 complete(&xpc_discovery_exited);
1383
1384                 xpc_do_exit(xpcUnloading);
1385                 return -EBUSY;
1386         }
1387
1388
1389         /* set the interface to point at XPC's functions */
1390         xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1391                           xpc_initiate_allocate, xpc_initiate_send,
1392                           xpc_initiate_send_notify, xpc_initiate_received,
1393                           xpc_initiate_partid_to_nasids);
1394
1395         return 0;
1396 }
1397 module_init(xpc_init);
1398
1399
1400 void __exit
1401 xpc_exit(void)
1402 {
1403         xpc_do_exit(xpcUnloading);
1404 }
1405 module_exit(xpc_exit);
1406
1407
1408 MODULE_AUTHOR("Silicon Graphics, Inc.");
1409 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1410 MODULE_LICENSE("GPL");
1411
1412 module_param(xpc_hb_interval, int, 0);
1413 MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1414                 "heartbeat increments.");
1415
1416 module_param(xpc_hb_check_interval, int, 0);
1417 MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1418                 "heartbeat checks.");
1419
1420 module_param(xpc_disengage_request_timelimit, int, 0);
1421 MODULE_PARM_DESC(xpc_disengage_request_timelimit, "Number of seconds to wait "
1422                 "for disengage request to complete.");
1423
1424 module_param(xpc_kdebug_ignore, int, 0);
1425 MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1426                 "other partitions when dropping into kdebug.");
1427