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/slab.h>
  56 #include <linux/delay.h>
  57 #include <linux/reboot.h>
  58 #include <linux/completion.h>
  59 #include <asm/sn/intr.h>
  60 #include <asm/sn/sn_sal.h>
  61 #include <asm/kdebug.h>
  62 #include <asm/uaccess.h>
  63 #include <asm/sn/xpc.h>
  64
  65
  66 /* define two XPC debug device structures to be used with dev_dbg() et al */
  67
  68 struct device_driver xpc_dbg_name = {
  69         .name = "xpc"
  70 };
  71
  72 struct device xpc_part_dbg_subname = {
  73         .bus_id = {0},          /* set to "part" at xpc_init() time */
  74         .driver = &xpc_dbg_name
  75 };
  76
  77 struct device xpc_chan_dbg_subname = {
  78         .bus_id = {0},          /* set to "chan" at xpc_init() time */
  79         .driver = &xpc_dbg_name
  80 };
  81
  82 struct device *xpc_part = &xpc_part_dbg_subname;
  83 struct device *xpc_chan = &xpc_chan_dbg_subname;
  84
  85
  86 static int xpc_kdebug_ignore;
  87
  88
  89 /* systune related variables for /proc/sys directories */
  90
  91 static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
  92 static int xpc_hb_min_interval = 1;
  93 static int xpc_hb_max_interval = 10;
  94
  95 static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
  96 static int xpc_hb_check_min_interval = 10;
  97 static int xpc_hb_check_max_interval = 120;
  98
  99 int xpc_disengage_request_timelimit = XPC_DISENGAGE_REQUEST_DEFAULT_TIMELIMIT;
 100 static int xpc_disengage_request_min_timelimit = 0;
 101 static int xpc_disengage_request_max_timelimit = 120;
 102
 103 static ctl_table xpc_sys_xpc_hb_dir[] = {
 104         {
 105                 1,
 106                 "hb_interval",
 107                 &xpc_hb_interval,
 108                 sizeof(int),
 109                 0644,
 110                 NULL,
 111                 &proc_dointvec_minmax,
 112                 NULL,
 113                 &sysctl_intvec,
 114                 NULL,
 115                 &xpc_hb_min_interval,
 116                 &xpc_hb_max_interval
 117         },
 118         {
 119                 2,
 120                 "hb_check_interval",
 121                 &xpc_hb_check_interval,
 122                 sizeof(int),
 123                 0644,
 124                 NULL,
 125                 &proc_dointvec_minmax,
 126                 NULL,
 127                 &sysctl_intvec,
 128                 NULL,
 129                 &xpc_hb_check_min_interval,
 130                 &xpc_hb_check_max_interval
 131         },
 132         {0}
 133 };
 134 static ctl_table xpc_sys_xpc_dir[] = {
 135         {
 136                 1,
 137                 "hb",
 138                 NULL,
 139                 0,
 140                 0555,
 141                 xpc_sys_xpc_hb_dir
 142         },
 143         {
 144                 2,
 145                 "disengage_request_timelimit",
 146                 &xpc_disengage_request_timelimit,
 147                 sizeof(int),
 148                 0644,
 149                 NULL,
 150                 &proc_dointvec_minmax,
 151                 NULL,
 152                 &sysctl_intvec,
 153                 NULL,
 154                 &xpc_disengage_request_min_timelimit,
 155                 &xpc_disengage_request_max_timelimit
 156         },
 157         {0}
 158 };
 159 static ctl_table xpc_sys_dir[] = {
 160         {
 161                 1,
 162                 "xpc",
 163                 NULL,
 164                 0,
 165                 0555,
 166                 xpc_sys_xpc_dir
 167         },
 168         {0}
 169 };
 170 static struct ctl_table_header *xpc_sysctl;
 171
 172 /* non-zero if any remote partition disengage request was timed out */
 173 int xpc_disengage_request_timedout;
 174
 175 /* #of IRQs received */
 176 static atomic_t xpc_act_IRQ_rcvd;
 177
 178 /* IRQ handler notifies this wait queue on receipt of an IRQ */
 179 static DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq);
 180
 181 static unsigned long xpc_hb_check_timeout;
 182
 183 /* notification that the xpc_hb_checker thread has exited */
 184 static DECLARE_COMPLETION(xpc_hb_checker_exited);
 185
 186 /* notification that the xpc_discovery thread has exited */
 187 static DECLARE_COMPLETION(xpc_discovery_exited);
 188
 189
 190 static struct timer_list xpc_hb_timer;
 191
 192
 193 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
 194
 195
 196 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
 197 static struct notifier_block xpc_reboot_notifier = {
 198         .notifier_call = xpc_system_reboot,
 199 };
 200
 201 static int xpc_system_die(struct notifier_block *, unsigned long, void *);
 202 static struct notifier_block xpc_die_notifier = {
 203         .notifier_call = xpc_system_die,
 204 };
 205
 206
 207 /*
 208  * Timer function to enforce the timelimit on the partition disengage request.
 209  */
 210 static void
 211 xpc_timeout_partition_disengage_request(unsigned long data)
 212 {
 213         struct xpc_partition *part = (struct xpc_partition *) data;
 214
 215
 216         DBUG_ON(jiffies < part->disengage_request_timeout);
 217
 218         (void) xpc_partition_disengaged(part);
 219
 220         DBUG_ON(part->disengage_request_timeout != 0);
 221         DBUG_ON(xpc_partition_engaged(1UL << XPC_PARTID(part)) != 0);
 222 }
 223
 224
 225 /*
 226  * Notify the heartbeat check thread that an IRQ has been received.
 227  */
 228 static irqreturn_t
 229 xpc_act_IRQ_handler(int irq, void *dev_id, struct pt_regs *regs)
 230 {
 231         atomic_inc(&xpc_act_IRQ_rcvd);
 232         wake_up_interruptible(&xpc_act_IRQ_wq);
 233         return IRQ_HANDLED;
 234 }
 235
 236
 237 /*
 238  * Timer to produce the heartbeat.  The timer structures function is
 239  * already set when this is initially called.  A tunable is used to
 240  * specify when the next timeout should occur.
 241  */
 242 static void
 243 xpc_hb_beater(unsigned long dummy)
 244 {
 245         xpc_vars->heartbeat++;
 246
 247         if (jiffies >= xpc_hb_check_timeout) {
 248                 wake_up_interruptible(&xpc_act_IRQ_wq);
 249         }
 250
 251         xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
 252         add_timer(&xpc_hb_timer);
 253 }
 254
 255
 256 /*
 257  * This thread is responsible for nearly all of the partition
 258  * activation/deactivation.
 259  */
 260 static int
 261 xpc_hb_checker(void *ignore)
 262 {
 263         int last_IRQ_count = 0;
 264         int new_IRQ_count;
 265         int force_IRQ=0;
 266
 267
 268         /* this thread was marked active by xpc_hb_init() */
 269
 270         daemonize(XPC_HB_CHECK_THREAD_NAME);
 271
 272         set_cpus_allowed(current, cpumask_of_cpu(XPC_HB_CHECK_CPU));
 273
 274         xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
 275
 276         while (!(volatile int) xpc_exiting) {
 277
 278                 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
 279                         "been received\n",
 280                         (int) (xpc_hb_check_timeout - jiffies),
 281                         atomic_read(&xpc_act_IRQ_rcvd) - last_IRQ_count);
 282
 283
 284                 /* checking of remote heartbeats is skewed by IRQ handling */
 285                 if (jiffies >= xpc_hb_check_timeout) {
 286                         dev_dbg(xpc_part, "checking remote heartbeats\n");
 287                         xpc_check_remote_hb();
 288
 289                         /*
 290                          * We need to periodically recheck to ensure no
 291                          * IPI/AMO pairs have been missed.  That check
 292                          * must always reset xpc_hb_check_timeout.
 293                          */
 294                         force_IRQ = 1;
 295                 }
 296
 297
 298                 /* check for outstanding IRQs */
 299                 new_IRQ_count = atomic_read(&xpc_act_IRQ_rcvd);
 300                 if (last_IRQ_count < new_IRQ_count || force_IRQ != 0) {
 301                         force_IRQ = 0;
 302
 303                         dev_dbg(xpc_part, "found an IRQ to process; will be "
 304                                 "resetting xpc_hb_check_timeout\n");
 305
 306                         last_IRQ_count += xpc_identify_act_IRQ_sender();
 307                         if (last_IRQ_count < new_IRQ_count) {
 308                                 /* retry once to help avoid missing AMO */
 309                                 (void) xpc_identify_act_IRQ_sender();
 310                         }
 311                         last_IRQ_count = new_IRQ_count;
 312
 313                         xpc_hb_check_timeout = jiffies +
 314                                            (xpc_hb_check_interval * HZ);
 315                 }
 316
 317                 /* wait for IRQ or timeout */
 318                 (void) wait_event_interruptible(xpc_act_IRQ_wq,
 319                             (last_IRQ_count < atomic_read(&xpc_act_IRQ_rcvd) ||
 320                                         jiffies >= xpc_hb_check_timeout ||
 321                                                 (volatile int) xpc_exiting));
 322         }
 323
 324         dev_dbg(xpc_part, "heartbeat checker is exiting\n");
 325
 326
 327         /* mark this thread as having exited */
 328         complete(&xpc_hb_checker_exited);
 329         return 0;
 330 }
 331
 332
 333 /*
 334  * This thread will attempt to discover other partitions to activate
 335  * based on info provided by SAL. This new thread is short lived and
 336  * will exit once discovery is complete.
 337  */
 338 static int
 339 xpc_initiate_discovery(void *ignore)
 340 {
 341         daemonize(XPC_DISCOVERY_THREAD_NAME);
 342
 343         xpc_discovery();
 344
 345         dev_dbg(xpc_part, "discovery thread is exiting\n");
 346
 347         /* mark this thread as having exited */
 348         complete(&xpc_discovery_exited);
 349         return 0;
 350 }
 351
 352
 353 /*
 354  * Establish first contact with the remote partititon. This involves pulling
 355  * the XPC per partition variables from the remote partition and waiting for
 356  * the remote partition to pull ours.
 357  */
 358 static enum xpc_retval
 359 xpc_make_first_contact(struct xpc_partition *part)
 360 {
 361         enum xpc_retval ret;
 362
 363
 364         while ((ret = xpc_pull_remote_vars_part(part)) != xpcSuccess) {
 365                 if (ret != xpcRetry) {
 366                         XPC_DEACTIVATE_PARTITION(part, ret);
 367                         return ret;
 368                 }
 369
 370                 dev_dbg(xpc_chan, "waiting to make first contact with "
 371                         "partition %d\n", XPC_PARTID(part));
 372
 373                 /* wait a 1/4 of a second or so */
 374                 (void) msleep_interruptible(250);
 375
 376                 if (part->act_state == XPC_P_DEACTIVATING) {
 377                         return part->reason;
 378                 }
 379         }
 380
 381         return xpc_mark_partition_active(part);
 382 }
 383
 384
 385 /*
 386  * The first kthread assigned to a newly activated partition is the one
 387  * created by XPC HB with which it calls xpc_partition_up(). XPC hangs on to
 388  * that kthread until the partition is brought down, at which time that kthread
 389  * returns back to XPC HB. (The return of that kthread will signify to XPC HB
 390  * that XPC has dismantled all communication infrastructure for the associated
 391  * partition.) This kthread becomes the channel manager for that partition.
 392  *
 393  * Each active partition has a channel manager, who, besides connecting and
 394  * disconnecting channels, will ensure that each of the partition's connected
 395  * channels has the required number of assigned kthreads to get the work done.
 396  */
 397 static void
 398 xpc_channel_mgr(struct xpc_partition *part)
 399 {
 400         while (part->act_state != XPC_P_DEACTIVATING ||
 401                         atomic_read(&part->nchannels_active) > 0 ||
 402                                         !xpc_partition_disengaged(part)) {
 403
 404                 xpc_process_channel_activity(part);
 405
 406
 407                 /*
 408                  * Wait until we've been requested to activate kthreads or
 409                  * all of the channel's message queues have been torn down or
 410                  * a signal is pending.
 411                  *
 412                  * The channel_mgr_requests is set to 1 after being awakened,
 413                  * This is done to prevent the channel mgr from making one pass
 414                  * through the loop for each request, since he will
 415                  * be servicing all the requests in one pass. The reason it's
 416                  * set to 1 instead of 0 is so that other kthreads will know
 417                  * that the channel mgr is running and won't bother trying to
 418                  * wake him up.
 419                  */
 420                 atomic_dec(&part->channel_mgr_requests);
 421                 (void) wait_event_interruptible(part->channel_mgr_wq,
 422                                 (atomic_read(&part->channel_mgr_requests) > 0 ||
 423                                 (volatile u64) part->local_IPI_amo != 0 ||
 424                                 ((volatile u8) part->act_state ==
 425                                                         XPC_P_DEACTIVATING &&
 426                                 atomic_read(&part->nchannels_active) == 0 &&
 427                                 xpc_partition_disengaged(part))));
 428                 atomic_set(&part->channel_mgr_requests, 1);
 429
 430                 // >>> Does it need to wakeup periodically as well? In case we
 431                 // >>> miscalculated the #of kthreads to wakeup or create?
 432         }
 433 }
 434
 435
 436 /*
 437  * When XPC HB determines that a partition has come up, it will create a new
 438  * kthread and that kthread will call this function to attempt to set up the
 439  * basic infrastructure used for Cross Partition Communication with the newly
 440  * upped partition.
 441  *
 442  * The kthread that was created by XPC HB and which setup the XPC
 443  * infrastructure will remain assigned to the partition until the partition
 444  * goes down. At which time the kthread will teardown the XPC infrastructure
 445  * and then exit.
 446  *
 447  * XPC HB will put the remote partition's XPC per partition specific variables
 448  * physical address into xpc_partitions[partid].remote_vars_part_pa prior to
 449  * calling xpc_partition_up().
 450  */
 451 static void
 452 xpc_partition_up(struct xpc_partition *part)
 453 {
 454         DBUG_ON(part->channels != NULL);
 455
 456         dev_dbg(xpc_chan, "activating partition %d\n", XPC_PARTID(part));
 457
 458         if (xpc_setup_infrastructure(part) != xpcSuccess) {
 459                 return;
 460         }
 461
 462         /*
 463          * The kthread that XPC HB called us with will become the
 464          * channel manager for this partition. It will not return
 465          * back to XPC HB until the partition's XPC infrastructure
 466          * has been dismantled.
 467          */
 468
 469         (void) xpc_part_ref(part);      /* this will always succeed */
 470
 471         if (xpc_make_first_contact(part) == xpcSuccess) {
 472                 xpc_channel_mgr(part);
 473         }
 474
 475         xpc_part_deref(part);
 476
 477         xpc_teardown_infrastructure(part);
 478 }
 479
 480
 481 static int
 482 xpc_activating(void *__partid)
 483 {
 484         partid_t partid = (u64) __partid;
 485         struct xpc_partition *part = &xpc_partitions[partid];
 486         unsigned long irq_flags;
 487         struct sched_param param = { sched_priority: MAX_RT_PRIO - 1 };
 488         int ret;
 489
 490
 491         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
 492
 493         spin_lock_irqsave(&part->act_lock, irq_flags);
 494
 495         if (part->act_state == XPC_P_DEACTIVATING) {
 496                 part->act_state = XPC_P_INACTIVE;
 497                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 498                 part->remote_rp_pa = 0;
 499                 return 0;
 500         }
 501
 502         /* indicate the thread is activating */
 503         DBUG_ON(part->act_state != XPC_P_ACTIVATION_REQ);
 504         part->act_state = XPC_P_ACTIVATING;
 505
 506         XPC_SET_REASON(part, 0, 0);
 507         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 508
 509         dev_dbg(xpc_part, "bringing partition %d up\n", partid);
 510
 511         daemonize("xpc%02d", partid);
 512
 513         /*
 514          * This thread needs to run at a realtime priority to prevent a
 515          * significant performance degradation.
 516          */
 517         ret = sched_setscheduler(current, SCHED_FIFO, &param);
 518         if (ret != 0) {
 519                 dev_warn(xpc_part, "unable to set pid %d to a realtime "
 520                         "priority, ret=%d\n", current->pid, ret);
 521         }
 522
 523         /* allow this thread and its children to run on any CPU */
 524         set_cpus_allowed(current, CPU_MASK_ALL);
 525
 526         /*
 527          * Register the remote partition's AMOs with SAL so it can handle
 528          * and cleanup errors within that address range should the remote
 529          * partition go down. We don't unregister this range because it is
 530          * difficult to tell when outstanding writes to the remote partition
 531          * are finished and thus when it is safe to unregister. This should
 532          * not result in wasted space in the SAL xp_addr_region table because
 533          * we should get the same page for remote_amos_page_pa after module
 534          * reloads and system reboots.
 535          */
 536         if (sn_register_xp_addr_region(part->remote_amos_page_pa,
 537                                                         PAGE_SIZE, 1) < 0) {
 538                 dev_warn(xpc_part, "xpc_partition_up(%d) failed to register "
 539                         "xp_addr region\n", partid);
 540
 541                 spin_lock_irqsave(&part->act_lock, irq_flags);
 542                 part->act_state = XPC_P_INACTIVE;
 543                 XPC_SET_REASON(part, xpcPhysAddrRegFailed, __LINE__);
 544                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 545                 part->remote_rp_pa = 0;
 546                 return 0;
 547         }
 548
 549         xpc_allow_hb(partid, xpc_vars);
 550         xpc_IPI_send_activated(part);
 551
 552
 553         /*
 554          * xpc_partition_up() holds this thread and marks this partition as
 555          * XPC_P_ACTIVE by calling xpc_hb_mark_active().
 556          */
 557         (void) xpc_partition_up(part);
 558
 559         xpc_disallow_hb(partid, xpc_vars);
 560         xpc_mark_partition_inactive(part);
 561
 562         if (part->reason == xpcReactivating) {
 563                 /* interrupting ourselves results in activating partition */
 564                 xpc_IPI_send_reactivate(part);
 565         }
 566
 567         return 0;
 568 }
 569
 570
 571 void
 572 xpc_activate_partition(struct xpc_partition *part)
 573 {
 574         partid_t partid = XPC_PARTID(part);
 575         unsigned long irq_flags;
 576         pid_t pid;
 577
 578
 579         spin_lock_irqsave(&part->act_lock, irq_flags);
 580
 581         DBUG_ON(part->act_state != XPC_P_INACTIVE);
 582
 583         part->act_state = XPC_P_ACTIVATION_REQ;
 584         XPC_SET_REASON(part, xpcCloneKThread, __LINE__);
 585
 586         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 587
 588         pid = kernel_thread(xpc_activating, (void *) ((u64) partid), 0);
 589
 590         if (unlikely(pid <= 0)) {
 591                 spin_lock_irqsave(&part->act_lock, irq_flags);
 592                 part->act_state = XPC_P_INACTIVE;
 593                 XPC_SET_REASON(part, xpcCloneKThreadFailed, __LINE__);
 594                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 595         }
 596 }
 597
 598
 599 /*
 600  * Handle the receipt of a SGI_XPC_NOTIFY IRQ by seeing whether the specified
 601  * partition actually sent it. Since SGI_XPC_NOTIFY IRQs may be shared by more
 602  * than one partition, we use an AMO_t structure per partition to indicate
 603  * whether a partition has sent an IPI or not.  >>> If it has, then wake up the
 604  * associated kthread to handle it.
 605  *
 606  * All SGI_XPC_NOTIFY IRQs received by XPC are the result of IPIs sent by XPC
 607  * running on other partitions.
 608  *
 609  * Noteworthy Arguments:
 610  *
 611  *      irq - Interrupt ReQuest number. NOT USED.
 612  *
 613  *      dev_id - partid of IPI's potential sender.
 614  *
 615  *      regs - processor's context before the processor entered
 616  *             interrupt code. NOT USED.
 617  */
 618 irqreturn_t
 619 xpc_notify_IRQ_handler(int irq, void *dev_id, struct pt_regs *regs)
 620 {
 621         partid_t partid = (partid_t) (u64) dev_id;
 622         struct xpc_partition *part = &xpc_partitions[partid];
 623
 624
 625         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
 626
 627         if (xpc_part_ref(part)) {
 628                 xpc_check_for_channel_activity(part);
 629
 630                 xpc_part_deref(part);
 631         }
 632         return IRQ_HANDLED;
 633 }
 634
 635
 636 /*
 637  * Check to see if xpc_notify_IRQ_handler() dropped any IPIs on the floor
 638  * because the write to their associated IPI amo completed after the IRQ/IPI
 639  * was received.
 640  */
 641 void
 642 xpc_dropped_IPI_check(struct xpc_partition *part)
 643 {
 644         if (xpc_part_ref(part)) {
 645                 xpc_check_for_channel_activity(part);
 646
 647                 part->dropped_IPI_timer.expires = jiffies +
 648                                                         XPC_P_DROPPED_IPI_WAIT;
 649                 add_timer(&part->dropped_IPI_timer);
 650                 xpc_part_deref(part);
 651         }
 652 }
 653
 654
 655 void
 656 xpc_activate_kthreads(struct xpc_channel *ch, int needed)
 657 {
 658         int idle = atomic_read(&ch->kthreads_idle);
 659         int assigned = atomic_read(&ch->kthreads_assigned);
 660         int wakeup;
 661
 662
 663         DBUG_ON(needed <= 0);
 664
 665         if (idle > 0) {
 666                 wakeup = (needed > idle) ? idle : needed;
 667                 needed -= wakeup;
 668
 669                 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
 670                         "channel=%d\n", wakeup, ch->partid, ch->number);
 671
 672                 /* only wakeup the requested number of kthreads */
 673                 wake_up_nr(&ch->idle_wq, wakeup);
 674         }
 675
 676         if (needed <= 0) {
 677                 return;
 678         }
 679
 680         if (needed + assigned > ch->kthreads_assigned_limit) {
 681                 needed = ch->kthreads_assigned_limit - assigned;
 682                 // >>>should never be less than 0
 683                 if (needed <= 0) {
 684                         return;
 685                 }
 686         }
 687
 688         dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
 689                 needed, ch->partid, ch->number);
 690
 691         xpc_create_kthreads(ch, needed);
 692 }
 693
 694
 695 /*
 696  * This function is where XPC's kthreads wait for messages to deliver.
 697  */
 698 static void
 699 xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
 700 {
 701         do {
 702                 /* deliver messages to their intended recipients */
 703
 704                 while ((volatile s64) ch->w_local_GP.get <
 705                                 (volatile s64) ch->w_remote_GP.put &&
 706                                         !((volatile u32) ch->flags &
 707                                                 XPC_C_DISCONNECTING)) {
 708                         xpc_deliver_msg(ch);
 709                 }
 710
 711                 if (atomic_inc_return(&ch->kthreads_idle) >
 712                                                 ch->kthreads_idle_limit) {
 713                         /* too many idle kthreads on this channel */
 714                         atomic_dec(&ch->kthreads_idle);
 715                         break;
 716                 }
 717
 718                 dev_dbg(xpc_chan, "idle kthread calling "
 719                         "wait_event_interruptible_exclusive()\n");
 720
 721                 (void) wait_event_interruptible_exclusive(ch->idle_wq,
 722                                 ((volatile s64) ch->w_local_GP.get <
 723                                         (volatile s64) ch->w_remote_GP.put ||
 724                                 ((volatile u32) ch->flags &
 725                                                 XPC_C_DISCONNECTING)));
 726
 727                 atomic_dec(&ch->kthreads_idle);
 728
 729         } while (!((volatile u32) ch->flags & XPC_C_DISCONNECTING));
 730 }
 731
 732
 733 static int
 734 xpc_daemonize_kthread(void *args)
 735 {
 736         partid_t partid = XPC_UNPACK_ARG1(args);
 737         u16 ch_number = XPC_UNPACK_ARG2(args);
 738         struct xpc_partition *part = &xpc_partitions[partid];
 739         struct xpc_channel *ch;
 740         int n_needed;
 741         unsigned long irq_flags;
 742
 743
 744         daemonize("xpc%02dc%d", partid, ch_number);
 745
 746         dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
 747                 partid, ch_number);
 748
 749         ch = &part->channels[ch_number];
 750
 751         if (!(ch->flags & XPC_C_DISCONNECTING)) {
 752
 753                 /* let registerer know that connection has been established */
 754
 755                 spin_lock_irqsave(&ch->lock, irq_flags);
 756                 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
 757                         ch->flags |= XPC_C_CONNECTEDCALLOUT;
 758                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 759
 760                         xpc_connected_callout(ch);
 761
 762                         spin_lock_irqsave(&ch->lock, irq_flags);
 763                         ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
 764                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 765
 766                         /*
 767                          * It is possible that while the callout was being
 768                          * made that the remote partition sent some messages.
 769                          * If that is the case, we may need to activate
 770                          * additional kthreads to help deliver them. We only
 771                          * need one less than total #of messages to deliver.
 772                          */
 773                         n_needed = ch->w_remote_GP.put - ch->w_local_GP.get - 1;
 774                         if (n_needed > 0 &&
 775                                         !(ch->flags & XPC_C_DISCONNECTING)) {
 776                                 xpc_activate_kthreads(ch, n_needed);
 777                         }
 778                 } else {
 779                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 780                 }
 781
 782                 xpc_kthread_waitmsgs(part, ch);
 783         }
 784
 785         if (atomic_dec_return(&ch->kthreads_assigned) == 0) {
 786                 spin_lock_irqsave(&ch->lock, irq_flags);
 787                 if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
 788                                 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
 789                         ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
 790                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 791
 792                         xpc_disconnect_callout(ch, xpcDisconnecting);
 793
 794                         spin_lock_irqsave(&ch->lock, irq_flags);
 795                         ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
 796                 }
 797                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 798                 if (atomic_dec_return(&part->nchannels_engaged) == 0) {
 799                         xpc_mark_partition_disengaged(part);
 800                         xpc_IPI_send_disengage(part);
 801                 }
 802         }
 803
 804
 805         xpc_msgqueue_deref(ch);
 806
 807         dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
 808                 partid, ch_number);
 809
 810         xpc_part_deref(part);
 811         return 0;
 812 }
 813
 814
 815 /*
 816  * For each partition that XPC has established communications with, there is
 817  * a minimum of one kernel thread assigned to perform any operation that
 818  * may potentially sleep or block (basically the callouts to the asynchronous
 819  * functions registered via xpc_connect()).
 820  *
 821  * Additional kthreads are created and destroyed by XPC as the workload
 822  * demands.
 823  *
 824  * A kthread is assigned to one of the active channels that exists for a given
 825  * partition.
 826  */
 827 void
 828 xpc_create_kthreads(struct xpc_channel *ch, int needed)
 829 {
 830         unsigned long irq_flags;
 831         pid_t pid;
 832         u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
 833         struct xpc_partition *part = &xpc_partitions[ch->partid];
 834
 835
 836         while (needed-- > 0) {
 837
 838                 /*
 839                  * The following is done on behalf of the newly created
 840                  * kthread. That kthread is responsible for doing the
 841                  * counterpart to the following before it exits.
 842                  */
 843                 (void) xpc_part_ref(part);
 844                 xpc_msgqueue_ref(ch);
 845                 if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
 846                     atomic_inc_return(&part->nchannels_engaged) == 1) {
 847                         xpc_mark_partition_engaged(part);
 848                 }
 849
 850                 pid = kernel_thread(xpc_daemonize_kthread, (void *) args, 0);
 851                 if (pid < 0) {
 852                         /* the fork failed */
 853                         if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 854                             atomic_dec_return(&part->nchannels_engaged) == 0) {
 855                                 xpc_mark_partition_disengaged(part);
 856                                 xpc_IPI_send_disengage(part);
 857                         }
 858                         xpc_msgqueue_deref(ch);
 859                         xpc_part_deref(part);
 860
 861                         if (atomic_read(&ch->kthreads_assigned) <
 862                                                 ch->kthreads_idle_limit) {
 863                                 /*
 864                                  * Flag this as an error only if we have an
 865                                  * insufficient #of kthreads for the channel
 866                                  * to function.
 867                                  *
 868                                  * No xpc_msgqueue_ref() is needed here since
 869                                  * the channel mgr is doing this.
 870                                  */
 871                                 spin_lock_irqsave(&ch->lock, irq_flags);
 872                                 XPC_DISCONNECT_CHANNEL(ch, xpcLackOfResources,
 873                                                                 &irq_flags);
 874                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 875                         }
 876                         break;
 877                 }
 878
 879                 ch->kthreads_created++; // >>> temporary debug only!!!
 880         }
 881 }
 882
 883
 884 void
 885 xpc_disconnect_wait(int ch_number)
 886 {
 887         unsigned long irq_flags;
 888         partid_t partid;
 889         struct xpc_partition *part;
 890         struct xpc_channel *ch;
 891         int wakeup_channel_mgr;
 892
 893
 894         /* now wait for all callouts to the caller's function to cease */
 895         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
 896                 part = &xpc_partitions[partid];
 897
 898                 if (!xpc_part_ref(part)) {
 899                         continue;
 900                 }
 901
 902                 ch = &part->channels[ch_number];
 903
 904                 if (!(ch->flags & XPC_C_WDISCONNECT)) {
 905                         xpc_part_deref(part);
 906                         continue;
 907                 }
 908
 909                 wait_for_completion(&ch->wdisconnect_wait);
 910
 911                 spin_lock_irqsave(&ch->lock, irq_flags);
 912                 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
 913                 wakeup_channel_mgr = 0;
 914
 915                 if (ch->delayed_IPI_flags) {
 916                         if (part->act_state != XPC_P_DEACTIVATING) {
 917                                 spin_lock(&part->IPI_lock);
 918                                 XPC_SET_IPI_FLAGS(part->local_IPI_amo,
 919                                         ch->number, ch->delayed_IPI_flags);
 920                                 spin_unlock(&part->IPI_lock);
 921                                 wakeup_channel_mgr = 1;
 922                         }
 923                         ch->delayed_IPI_flags = 0;
 924                 }
 925
 926                 ch->flags &= ~XPC_C_WDISCONNECT;
 927                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 928
 929                 if (wakeup_channel_mgr) {
 930                         xpc_wakeup_channel_mgr(part);
 931                 }
 932
 933                 xpc_part_deref(part);
 934         }
 935 }
 936
 937
 938 static void
 939 xpc_do_exit(enum xpc_retval reason)
 940 {
 941         partid_t partid;
 942         int active_part_count, printed_waiting_msg = 0;
 943         struct xpc_partition *part;
 944         unsigned long printmsg_time, disengage_request_timeout = 0;
 945
 946
 947         /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
 948         DBUG_ON(xpc_exiting == 1);
 949
 950         /*
 951          * Let the heartbeat checker thread and the discovery thread
 952          * (if one is running) know that they should exit. Also wake up
 953          * the heartbeat checker thread in case it's sleeping.
 954          */
 955         xpc_exiting = 1;
 956         wake_up_interruptible(&xpc_act_IRQ_wq);
 957
 958         /* ignore all incoming interrupts */
 959         free_irq(SGI_XPC_ACTIVATE, NULL);
 960
 961         /* wait for the discovery thread to exit */
 962         wait_for_completion(&xpc_discovery_exited);
 963
 964         /* wait for the heartbeat checker thread to exit */
 965         wait_for_completion(&xpc_hb_checker_exited);
 966
 967
 968         /* sleep for a 1/3 of a second or so */
 969         (void) msleep_interruptible(300);
 970
 971
 972         /* wait for all partitions to become inactive */
 973
 974         printmsg_time = jiffies + (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
 975         xpc_disengage_request_timedout = 0;
 976
 977         do {
 978                 active_part_count = 0;
 979
 980                 for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
 981                         part = &xpc_partitions[partid];
 982
 983                         if (xpc_partition_disengaged(part) &&
 984                                         part->act_state == XPC_P_INACTIVE) {
 985                                 continue;
 986                         }
 987
 988                         active_part_count++;
 989
 990                         XPC_DEACTIVATE_PARTITION(part, reason);
 991
 992                         if (part->disengage_request_timeout >
 993                                                 disengage_request_timeout) {
 994                                 disengage_request_timeout =
 995                                                 part->disengage_request_timeout;
 996                         }
 997                 }
 998
 999                 if (xpc_partition_engaged(-1UL)) {
1000                         if (time_after(jiffies, printmsg_time)) {
1001                                 dev_info(xpc_part, "waiting for remote "
1002                                         "partitions to disengage, timeout in "
1003                                         "%ld seconds\n",
1004                                         (disengage_request_timeout - jiffies)
1005                                                                         / HZ);
1006                                 printmsg_time = jiffies +
1007                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
1008                                 printed_waiting_msg = 1;
1009                         }
1010
1011                 } else if (active_part_count > 0) {
1012                         if (printed_waiting_msg) {
1013                                 dev_info(xpc_part, "waiting for local partition"
1014                                         " to disengage\n");
1015                                 printed_waiting_msg = 0;
1016                         }
1017
1018                 } else {
1019                         if (!xpc_disengage_request_timedout) {
1020                                 dev_info(xpc_part, "all partitions have "
1021                                         "disengaged\n");
1022                         }
1023                         break;
1024                 }
1025
1026                 /* sleep for a 1/3 of a second or so */
1027                 (void) msleep_interruptible(300);
1028
1029         } while (1);
1030
1031         DBUG_ON(xpc_partition_engaged(-1UL));
1032
1033
1034         /* indicate to others that our reserved page is uninitialized */
1035         xpc_rsvd_page->vars_pa = 0;
1036
1037         /* now it's time to eliminate our heartbeat */
1038         del_timer_sync(&xpc_hb_timer);
1039         DBUG_ON(xpc_vars->heartbeating_to_mask != 0);
1040
1041         if (reason == xpcUnloading) {
1042                 /* take ourselves off of the reboot_notifier_list */
1043                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1044
1045                 /* take ourselves off of the die_notifier list */
1046                 (void) unregister_die_notifier(&xpc_die_notifier);
1047         }
1048
1049         /* close down protections for IPI operations */
1050         xpc_restrict_IPI_ops();
1051
1052
1053         /* clear the interface to XPC's functions */
1054         xpc_clear_interface();
1055
1056         if (xpc_sysctl) {
1057                 unregister_sysctl_table(xpc_sysctl);
1058         }
1059
1060         kfree(xpc_remote_copy_buffer_base);
1061 }
1062
1063
1064 /*
1065  * This function is called when the system is being rebooted.
1066  */
1067 static int
1068 xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1069 {
1070         enum xpc_retval reason;
1071
1072
1073         switch (event) {
1074         case SYS_RESTART:
1075                 reason = xpcSystemReboot;
1076                 break;
1077         case SYS_HALT:
1078                 reason = xpcSystemHalt;
1079                 break;
1080         case SYS_POWER_OFF:
1081                 reason = xpcSystemPoweroff;
1082                 break;
1083         default:
1084                 reason = xpcSystemGoingDown;
1085         }
1086
1087         xpc_do_exit(reason);
1088         return NOTIFY_DONE;
1089 }
1090
1091
1092 /*
1093  * Notify other partitions to disengage from all references to our memory.
1094  */
1095 static void
1096 xpc_die_disengage(void)
1097 {
1098         struct xpc_partition *part;
1099         partid_t partid;
1100         unsigned long engaged;
1101         long time, printmsg_time, disengage_request_timeout;
1102
1103
1104         /* keep xpc_hb_checker thread from doing anything (just in case) */
1105         xpc_exiting = 1;
1106
1107         xpc_vars->heartbeating_to_mask = 0;  /* indicate we're deactivated */
1108
1109         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1110                 part = &xpc_partitions[partid];
1111
1112                 if (!XPC_SUPPORTS_DISENGAGE_REQUEST(part->
1113                                                         remote_vars_version)) {
1114
1115                         /* just in case it was left set by an earlier XPC */
1116                         xpc_clear_partition_engaged(1UL << partid);
1117                         continue;
1118                 }
1119
1120                 if (xpc_partition_engaged(1UL << partid) ||
1121                                         part->act_state != XPC_P_INACTIVE) {
1122                         xpc_request_partition_disengage(part);
1123                         xpc_mark_partition_disengaged(part);
1124                         xpc_IPI_send_disengage(part);
1125                 }
1126         }
1127
1128         time = rtc_time();
1129         printmsg_time = time +
1130                 (XPC_DISENGAGE_PRINTMSG_INTERVAL * sn_rtc_cycles_per_second);
1131         disengage_request_timeout = time +
1132                 (xpc_disengage_request_timelimit * sn_rtc_cycles_per_second);
1133
1134         /* wait for all other partitions to disengage from us */
1135
1136         while (1) {
1137                 engaged = xpc_partition_engaged(-1UL);
1138                 if (!engaged) {
1139                         dev_info(xpc_part, "all partitions have disengaged\n");
1140                         break;
1141                 }
1142
1143                 time = rtc_time();
1144                 if (time >= disengage_request_timeout) {
1145                         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1146                                 if (engaged & (1UL << partid)) {
1147                                         dev_info(xpc_part, "disengage from "
1148                                                 "remote partition %d timed "
1149                                                 "out\n", partid);
1150                                 }
1151                         }
1152                         break;
1153                 }
1154
1155                 if (time >= printmsg_time) {
1156                         dev_info(xpc_part, "waiting for remote partitions to "
1157                                 "disengage, timeout in %ld seconds\n",
1158                                 (disengage_request_timeout - time) /
1159                                                 sn_rtc_cycles_per_second);
1160                         printmsg_time = time +
1161                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL *
1162                                                 sn_rtc_cycles_per_second);
1163                 }
1164         }
1165 }
1166
1167
1168 /*
1169  * This function is called when the system is being restarted or halted due
1170  * to some sort of system failure. If this is the case we need to notify the
1171  * other partitions to disengage from all references to our memory.
1172  * This function can also be called when our heartbeater could be offlined
1173  * for a time. In this case we need to notify other partitions to not worry
1174  * about the lack of a heartbeat.
1175  */
1176 static int
1177 xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1178 {
1179         switch (event) {
1180         case DIE_MACHINE_RESTART:
1181         case DIE_MACHINE_HALT:
1182                 xpc_die_disengage();
1183                 break;
1184
1185         case DIE_KDEBUG_ENTER:
1186                 /* Should lack of heartbeat be ignored by other partitions? */
1187                 if (!xpc_kdebug_ignore) {
1188                         break;
1189                 }
1190                 /* fall through */
1191         case DIE_MCA_MONARCH_ENTER:
1192         case DIE_INIT_MONARCH_ENTER:
1193                 xpc_vars->heartbeat++;
1194                 xpc_vars->heartbeat_offline = 1;
1195                 break;
1196
1197         case DIE_KDEBUG_LEAVE:
1198                 /* Is lack of heartbeat being ignored by other partitions? */
1199                 if (!xpc_kdebug_ignore) {
1200                         break;
1201                 }
1202                 /* fall through */
1203         case DIE_MCA_MONARCH_LEAVE:
1204         case DIE_INIT_MONARCH_LEAVE:
1205                 xpc_vars->heartbeat++;
1206                 xpc_vars->heartbeat_offline = 0;
1207                 break;
1208         }
1209
1210         return NOTIFY_DONE;
1211 }
1212
1213
1214 int __init
1215 xpc_init(void)
1216 {
1217         int ret;
1218         partid_t partid;
1219         struct xpc_partition *part;
1220         pid_t pid;
1221         size_t buf_size;
1222
1223
1224         if (!ia64_platform_is("sn2")) {
1225                 return -ENODEV;
1226         }
1227
1228
1229         buf_size = max(XPC_RP_VARS_SIZE,
1230                                 XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES);
1231         xpc_remote_copy_buffer = xpc_kmalloc_cacheline_aligned(buf_size,
1232                                      GFP_KERNEL, &xpc_remote_copy_buffer_base);
1233         if (xpc_remote_copy_buffer == NULL)
1234                 return -ENOMEM;
1235
1236         snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
1237         snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
1238
1239         xpc_sysctl = register_sysctl_table(xpc_sys_dir, 1);
1240
1241         /*
1242          * The first few fields of each entry of xpc_partitions[] need to
1243          * be initialized now so that calls to xpc_connect() and
1244          * xpc_disconnect() can be made prior to the activation of any remote
1245          * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
1246          * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
1247          * PARTITION HAS BEEN ACTIVATED.
1248          */
1249         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1250                 part = &xpc_partitions[partid];
1251
1252                 DBUG_ON((u64) part != L1_CACHE_ALIGN((u64) part));
1253
1254                 part->act_IRQ_rcvd = 0;
1255                 spin_lock_init(&part->act_lock);
1256                 part->act_state = XPC_P_INACTIVE;
1257                 XPC_SET_REASON(part, 0, 0);
1258
1259                 init_timer(&part->disengage_request_timer);
1260                 part->disengage_request_timer.function =
1261                                 xpc_timeout_partition_disengage_request;
1262                 part->disengage_request_timer.data = (unsigned long) part;
1263
1264                 part->setup_state = XPC_P_UNSET;
1265                 init_waitqueue_head(&part->teardown_wq);
1266                 atomic_set(&part->references, 0);
1267         }
1268
1269         /*
1270          * Open up protections for IPI operations (and AMO operations on
1271          * Shub 1.1 systems).
1272          */
1273         xpc_allow_IPI_ops();
1274
1275         /*
1276          * Interrupts being processed will increment this atomic variable and
1277          * awaken the heartbeat thread which will process the interrupts.
1278          */
1279         atomic_set(&xpc_act_IRQ_rcvd, 0);
1280
1281         /*
1282          * This is safe to do before the xpc_hb_checker thread has started
1283          * because the handler releases a wait queue.  If an interrupt is
1284          * received before the thread is waiting, it will not go to sleep,
1285          * but rather immediately process the interrupt.
1286          */
1287         ret = request_irq(SGI_XPC_ACTIVATE, xpc_act_IRQ_handler, 0,
1288                                                         "xpc hb", NULL);
1289         if (ret != 0) {
1290                 dev_err(xpc_part, "can't register ACTIVATE IRQ handler, "
1291                         "errno=%d\n", -ret);
1292
1293                 xpc_restrict_IPI_ops();
1294
1295                 if (xpc_sysctl) {
1296                         unregister_sysctl_table(xpc_sysctl);
1297                 }
1298
1299                 kfree(xpc_remote_copy_buffer_base);
1300                 return -EBUSY;
1301         }
1302
1303         /*
1304          * Fill the partition reserved page with the information needed by
1305          * other partitions to discover we are alive and establish initial
1306          * communications.
1307          */
1308         xpc_rsvd_page = xpc_rsvd_page_init();
1309         if (xpc_rsvd_page == NULL) {
1310                 dev_err(xpc_part, "could not setup our reserved page\n");
1311
1312                 free_irq(SGI_XPC_ACTIVATE, NULL);
1313                 xpc_restrict_IPI_ops();
1314
1315                 if (xpc_sysctl) {
1316                         unregister_sysctl_table(xpc_sysctl);
1317                 }
1318
1319                 kfree(xpc_remote_copy_buffer_base);
1320                 return -EBUSY;
1321         }
1322
1323
1324         /* add ourselves to the reboot_notifier_list */
1325         ret = register_reboot_notifier(&xpc_reboot_notifier);
1326         if (ret != 0) {
1327                 dev_warn(xpc_part, "can't register reboot notifier\n");
1328         }
1329
1330         /* add ourselves to the die_notifier list (i.e., ia64die_chain) */
1331         ret = register_die_notifier(&xpc_die_notifier);
1332         if (ret != 0) {
1333                 dev_warn(xpc_part, "can't register die notifier\n");
1334         }
1335
1336
1337         /*
1338          * Set the beating to other partitions into motion.  This is
1339          * the last requirement for other partitions' discovery to
1340          * initiate communications with us.
1341          */
1342         init_timer(&xpc_hb_timer);
1343         xpc_hb_timer.function = xpc_hb_beater;
1344         xpc_hb_beater(0);
1345
1346
1347         /*
1348          * The real work-horse behind xpc.  This processes incoming
1349          * interrupts and monitors remote heartbeats.
1350          */
1351         pid = kernel_thread(xpc_hb_checker, NULL, 0);
1352         if (pid < 0) {
1353                 dev_err(xpc_part, "failed while forking hb check thread\n");
1354
1355                 /* indicate to others that our reserved page is uninitialized */
1356                 xpc_rsvd_page->vars_pa = 0;
1357
1358                 /* take ourselves off of the reboot_notifier_list */
1359                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1360
1361                 /* take ourselves off of the die_notifier list */
1362                 (void) unregister_die_notifier(&xpc_die_notifier);
1363
1364                 del_timer_sync(&xpc_hb_timer);
1365                 free_irq(SGI_XPC_ACTIVATE, NULL);
1366                 xpc_restrict_IPI_ops();
1367
1368                 if (xpc_sysctl) {
1369                         unregister_sysctl_table(xpc_sysctl);
1370                 }
1371
1372                 kfree(xpc_remote_copy_buffer_base);
1373                 return -EBUSY;
1374         }
1375
1376
1377         /*
1378          * Startup a thread that will attempt to discover other partitions to
1379          * activate based on info provided by SAL. This new thread is short
1380          * lived and will exit once discovery is complete.
1381          */
1382         pid = kernel_thread(xpc_initiate_discovery, NULL, 0);
1383         if (pid < 0) {
1384                 dev_err(xpc_part, "failed while forking discovery thread\n");
1385
1386                 /* mark this new thread as a non-starter */
1387                 complete(&xpc_discovery_exited);
1388
1389                 xpc_do_exit(xpcUnloading);
1390                 return -EBUSY;
1391         }
1392
1393
1394         /* set the interface to point at XPC's functions */
1395         xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1396                           xpc_initiate_allocate, xpc_initiate_send,
1397                           xpc_initiate_send_notify, xpc_initiate_received,
1398                           xpc_initiate_partid_to_nasids);
1399
1400         return 0;
1401 }
1402 module_init(xpc_init);
1403
1404
1405 void __exit
1406 xpc_exit(void)
1407 {
1408         xpc_do_exit(xpcUnloading);
1409 }
1410 module_exit(xpc_exit);
1411
1412
1413 MODULE_AUTHOR("Silicon Graphics, Inc.");
1414 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1415 MODULE_LICENSE("GPL");
1416
1417 module_param(xpc_hb_interval, int, 0);
1418 MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1419                 "heartbeat increments.");
1420
1421 module_param(xpc_hb_check_interval, int, 0);
1422 MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1423                 "heartbeat checks.");
1424
1425 module_param(xpc_disengage_request_timelimit, int, 0);
1426 MODULE_PARM_DESC(xpc_disengage_request_timelimit, "Number of seconds to wait "
1427                 "for disengage request to complete.");
1428
1429 module_param(xpc_kdebug_ignore, int, 0);
1430 MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1431                 "other partitions when dropping into kdebug.");
1432