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                 .ctl_name       = CTL_UNNUMBERED,
 105                 .procname       = "hb_interval",
 106                 .data           = &xpc_hb_interval,
 107                 .maxlen         = sizeof(int),
 108                 .mode           = 0644,
 109                 .proc_handler   = &proc_dointvec_minmax,
 110                 .strategy       = &sysctl_intvec,
 111                 .extra1         = &xpc_hb_min_interval,
 112                 .extra2         = &xpc_hb_max_interval
 113         },
 114         {
 115                 .ctl_name       = CTL_UNNUMBERED,
 116                 .procname       = "hb_check_interval",
 117                 .data           = &xpc_hb_check_interval,
 118                 .maxlen         = sizeof(int),
 119                 .mode           = 0644,
 120                 .proc_handler   = &proc_dointvec_minmax,
 121                 .strategy       = &sysctl_intvec,
 122                 .extra1         = &xpc_hb_check_min_interval,
 123                 .extra2         = &xpc_hb_check_max_interval
 124         },
 125         {}
 126 };
 127 static ctl_table xpc_sys_xpc_dir[] = {
 128         {
 129                 .ctl_name       = CTL_UNNUMBERED,
 130                 .procname       = "hb",
 131                 .mode           = 0555,
 132                 .child          = xpc_sys_xpc_hb_dir
 133         },
 134         {
 135                 .ctl_name       = CTL_UNNUMBERED,
 136                 .procname       = "disengage_request_timelimit",
 137                 .data           = &xpc_disengage_request_timelimit,
 138                 .maxlen         = sizeof(int),
 139                 .mode           = 0644,
 140                 .proc_handler   = &proc_dointvec_minmax,
 141                 .strategy       = &sysctl_intvec,
 142                 .extra1         = &xpc_disengage_request_min_timelimit,
 143                 .extra2         = &xpc_disengage_request_max_timelimit
 144         },
 145         {}
 146 };
 147 static ctl_table xpc_sys_dir[] = {
 148         {
 149                 .ctl_name       = CTL_UNNUMBERED,
 150                 .procname       = "xpc",
 151                 .mode           = 0555,
 152                 .child          = xpc_sys_xpc_dir
 153         },
 154         {}
 155 };
 156 static struct ctl_table_header *xpc_sysctl;
 157
 158 /* non-zero if any remote partition disengage request was timed out */
 159 int xpc_disengage_request_timedout;
 160
 161 /* #of IRQs received */
 162 static atomic_t xpc_act_IRQ_rcvd;
 163
 164 /* IRQ handler notifies this wait queue on receipt of an IRQ */
 165 static DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq);
 166
 167 static unsigned long xpc_hb_check_timeout;
 168
 169 /* notification that the xpc_hb_checker thread has exited */
 170 static DECLARE_COMPLETION(xpc_hb_checker_exited);
 171
 172 /* notification that the xpc_discovery thread has exited */
 173 static DECLARE_COMPLETION(xpc_discovery_exited);
 174
 175
 176 static struct timer_list xpc_hb_timer;
 177
 178
 179 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
 180
 181
 182 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
 183 static struct notifier_block xpc_reboot_notifier = {
 184         .notifier_call = xpc_system_reboot,
 185 };
 186
 187 static int xpc_system_die(struct notifier_block *, unsigned long, void *);
 188 static struct notifier_block xpc_die_notifier = {
 189         .notifier_call = xpc_system_die,
 190 };
 191
 192
 193 /*
 194  * Timer function to enforce the timelimit on the partition disengage request.
 195  */
 196 static void
 197 xpc_timeout_partition_disengage_request(unsigned long data)
 198 {
 199         struct xpc_partition *part = (struct xpc_partition *) data;
 200
 201
 202         DBUG_ON(jiffies < part->disengage_request_timeout);
 203
 204         (void) xpc_partition_disengaged(part);
 205
 206         DBUG_ON(part->disengage_request_timeout != 0);
 207         DBUG_ON(xpc_partition_engaged(1UL << XPC_PARTID(part)) != 0);
 208 }
 209
 210
 211 /*
 212  * Notify the heartbeat check thread that an IRQ has been received.
 213  */
 214 static irqreturn_t
 215 xpc_act_IRQ_handler(int irq, void *dev_id)
 216 {
 217         atomic_inc(&xpc_act_IRQ_rcvd);
 218         wake_up_interruptible(&xpc_act_IRQ_wq);
 219         return IRQ_HANDLED;
 220 }
 221
 222
 223 /*
 224  * Timer to produce the heartbeat.  The timer structures function is
 225  * already set when this is initially called.  A tunable is used to
 226  * specify when the next timeout should occur.
 227  */
 228 static void
 229 xpc_hb_beater(unsigned long dummy)
 230 {
 231         xpc_vars->heartbeat++;
 232
 233         if (jiffies >= xpc_hb_check_timeout) {
 234                 wake_up_interruptible(&xpc_act_IRQ_wq);
 235         }
 236
 237         xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
 238         add_timer(&xpc_hb_timer);
 239 }
 240
 241
 242 /*
 243  * This thread is responsible for nearly all of the partition
 244  * activation/deactivation.
 245  */
 246 static int
 247 xpc_hb_checker(void *ignore)
 248 {
 249         int last_IRQ_count = 0;
 250         int new_IRQ_count;
 251         int force_IRQ=0;
 252
 253
 254         /* this thread was marked active by xpc_hb_init() */
 255
 256         daemonize(XPC_HB_CHECK_THREAD_NAME);
 257
 258         set_cpus_allowed(current, cpumask_of_cpu(XPC_HB_CHECK_CPU));
 259
 260         xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
 261
 262         while (!(volatile int) xpc_exiting) {
 263
 264                 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
 265                         "been received\n",
 266                         (int) (xpc_hb_check_timeout - jiffies),
 267                         atomic_read(&xpc_act_IRQ_rcvd) - last_IRQ_count);
 268
 269
 270                 /* checking of remote heartbeats is skewed by IRQ handling */
 271                 if (jiffies >= xpc_hb_check_timeout) {
 272                         dev_dbg(xpc_part, "checking remote heartbeats\n");
 273                         xpc_check_remote_hb();
 274
 275                         /*
 276                          * We need to periodically recheck to ensure no
 277                          * IPI/AMO pairs have been missed.  That check
 278                          * must always reset xpc_hb_check_timeout.
 279                          */
 280                         force_IRQ = 1;
 281                 }
 282
 283
 284                 /* check for outstanding IRQs */
 285                 new_IRQ_count = atomic_read(&xpc_act_IRQ_rcvd);
 286                 if (last_IRQ_count < new_IRQ_count || force_IRQ != 0) {
 287                         force_IRQ = 0;
 288
 289                         dev_dbg(xpc_part, "found an IRQ to process; will be "
 290                                 "resetting xpc_hb_check_timeout\n");
 291
 292                         last_IRQ_count += xpc_identify_act_IRQ_sender();
 293                         if (last_IRQ_count < new_IRQ_count) {
 294                                 /* retry once to help avoid missing AMO */
 295                                 (void) xpc_identify_act_IRQ_sender();
 296                         }
 297                         last_IRQ_count = new_IRQ_count;
 298
 299                         xpc_hb_check_timeout = jiffies +
 300                                            (xpc_hb_check_interval * HZ);
 301                 }
 302
 303                 /* wait for IRQ or timeout */
 304                 (void) wait_event_interruptible(xpc_act_IRQ_wq,
 305                             (last_IRQ_count < atomic_read(&xpc_act_IRQ_rcvd) ||
 306                                         jiffies >= xpc_hb_check_timeout ||
 307                                                 (volatile int) xpc_exiting));
 308         }
 309
 310         dev_dbg(xpc_part, "heartbeat checker is exiting\n");
 311
 312
 313         /* mark this thread as having exited */
 314         complete(&xpc_hb_checker_exited);
 315         return 0;
 316 }
 317
 318
 319 /*
 320  * This thread will attempt to discover other partitions to activate
 321  * based on info provided by SAL. This new thread is short lived and
 322  * will exit once discovery is complete.
 323  */
 324 static int
 325 xpc_initiate_discovery(void *ignore)
 326 {
 327         daemonize(XPC_DISCOVERY_THREAD_NAME);
 328
 329         xpc_discovery();
 330
 331         dev_dbg(xpc_part, "discovery thread is exiting\n");
 332
 333         /* mark this thread as having exited */
 334         complete(&xpc_discovery_exited);
 335         return 0;
 336 }
 337
 338
 339 /*
 340  * Establish first contact with the remote partititon. This involves pulling
 341  * the XPC per partition variables from the remote partition and waiting for
 342  * the remote partition to pull ours.
 343  */
 344 static enum xpc_retval
 345 xpc_make_first_contact(struct xpc_partition *part)
 346 {
 347         enum xpc_retval ret;
 348
 349
 350         while ((ret = xpc_pull_remote_vars_part(part)) != xpcSuccess) {
 351                 if (ret != xpcRetry) {
 352                         XPC_DEACTIVATE_PARTITION(part, ret);
 353                         return ret;
 354                 }
 355
 356                 dev_dbg(xpc_chan, "waiting to make first contact with "
 357                         "partition %d\n", XPC_PARTID(part));
 358
 359                 /* wait a 1/4 of a second or so */
 360                 (void) msleep_interruptible(250);
 361
 362                 if (part->act_state == XPC_P_DEACTIVATING) {
 363                         return part->reason;
 364                 }
 365         }
 366
 367         return xpc_mark_partition_active(part);
 368 }
 369
 370
 371 /*
 372  * The first kthread assigned to a newly activated partition is the one
 373  * created by XPC HB with which it calls xpc_partition_up(). XPC hangs on to
 374  * that kthread until the partition is brought down, at which time that kthread
 375  * returns back to XPC HB. (The return of that kthread will signify to XPC HB
 376  * that XPC has dismantled all communication infrastructure for the associated
 377  * partition.) This kthread becomes the channel manager for that partition.
 378  *
 379  * Each active partition has a channel manager, who, besides connecting and
 380  * disconnecting channels, will ensure that each of the partition's connected
 381  * channels has the required number of assigned kthreads to get the work done.
 382  */
 383 static void
 384 xpc_channel_mgr(struct xpc_partition *part)
 385 {
 386         while (part->act_state != XPC_P_DEACTIVATING ||
 387                         atomic_read(&part->nchannels_active) > 0 ||
 388                                         !xpc_partition_disengaged(part)) {
 389
 390                 xpc_process_channel_activity(part);
 391
 392
 393                 /*
 394                  * Wait until we've been requested to activate kthreads or
 395                  * all of the channel's message queues have been torn down or
 396                  * a signal is pending.
 397                  *
 398                  * The channel_mgr_requests is set to 1 after being awakened,
 399                  * This is done to prevent the channel mgr from making one pass
 400                  * through the loop for each request, since he will
 401                  * be servicing all the requests in one pass. The reason it's
 402                  * set to 1 instead of 0 is so that other kthreads will know
 403                  * that the channel mgr is running and won't bother trying to
 404                  * wake him up.
 405                  */
 406                 atomic_dec(&part->channel_mgr_requests);
 407                 (void) wait_event_interruptible(part->channel_mgr_wq,
 408                                 (atomic_read(&part->channel_mgr_requests) > 0 ||
 409                                 (volatile u64) part->local_IPI_amo != 0 ||
 410                                 ((volatile u8) part->act_state ==
 411                                                         XPC_P_DEACTIVATING &&
 412                                 atomic_read(&part->nchannels_active) == 0 &&
 413                                 xpc_partition_disengaged(part))));
 414                 atomic_set(&part->channel_mgr_requests, 1);
 415
 416                 // >>> Does it need to wakeup periodically as well? In case we
 417                 // >>> miscalculated the #of kthreads to wakeup or create?
 418         }
 419 }
 420
 421
 422 /*
 423  * When XPC HB determines that a partition has come up, it will create a new
 424  * kthread and that kthread will call this function to attempt to set up the
 425  * basic infrastructure used for Cross Partition Communication with the newly
 426  * upped partition.
 427  *
 428  * The kthread that was created by XPC HB and which setup the XPC
 429  * infrastructure will remain assigned to the partition until the partition
 430  * goes down. At which time the kthread will teardown the XPC infrastructure
 431  * and then exit.
 432  *
 433  * XPC HB will put the remote partition's XPC per partition specific variables
 434  * physical address into xpc_partitions[partid].remote_vars_part_pa prior to
 435  * calling xpc_partition_up().
 436  */
 437 static void
 438 xpc_partition_up(struct xpc_partition *part)
 439 {
 440         DBUG_ON(part->channels != NULL);
 441
 442         dev_dbg(xpc_chan, "activating partition %d\n", XPC_PARTID(part));
 443
 444         if (xpc_setup_infrastructure(part) != xpcSuccess) {
 445                 return;
 446         }
 447
 448         /*
 449          * The kthread that XPC HB called us with will become the
 450          * channel manager for this partition. It will not return
 451          * back to XPC HB until the partition's XPC infrastructure
 452          * has been dismantled.
 453          */
 454
 455         (void) xpc_part_ref(part);      /* this will always succeed */
 456
 457         if (xpc_make_first_contact(part) == xpcSuccess) {
 458                 xpc_channel_mgr(part);
 459         }
 460
 461         xpc_part_deref(part);
 462
 463         xpc_teardown_infrastructure(part);
 464 }
 465
 466
 467 static int
 468 xpc_activating(void *__partid)
 469 {
 470         partid_t partid = (u64) __partid;
 471         struct xpc_partition *part = &xpc_partitions[partid];
 472         unsigned long irq_flags;
 473         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
 474         int ret;
 475
 476
 477         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
 478
 479         spin_lock_irqsave(&part->act_lock, irq_flags);
 480
 481         if (part->act_state == XPC_P_DEACTIVATING) {
 482                 part->act_state = XPC_P_INACTIVE;
 483                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 484                 part->remote_rp_pa = 0;
 485                 return 0;
 486         }
 487
 488         /* indicate the thread is activating */
 489         DBUG_ON(part->act_state != XPC_P_ACTIVATION_REQ);
 490         part->act_state = XPC_P_ACTIVATING;
 491
 492         XPC_SET_REASON(part, 0, 0);
 493         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 494
 495         dev_dbg(xpc_part, "bringing partition %d up\n", partid);
 496
 497         daemonize("xpc%02d", partid);
 498
 499         /*
 500          * This thread needs to run at a realtime priority to prevent a
 501          * significant performance degradation.
 502          */
 503         ret = sched_setscheduler(current, SCHED_FIFO, &param);
 504         if (ret != 0) {
 505                 dev_warn(xpc_part, "unable to set pid %d to a realtime "
 506                         "priority, ret=%d\n", current->pid, ret);
 507         }
 508
 509         /* allow this thread and its children to run on any CPU */
 510         set_cpus_allowed(current, CPU_MASK_ALL);
 511
 512         /*
 513          * Register the remote partition's AMOs with SAL so it can handle
 514          * and cleanup errors within that address range should the remote
 515          * partition go down. We don't unregister this range because it is
 516          * difficult to tell when outstanding writes to the remote partition
 517          * are finished and thus when it is safe to unregister. This should
 518          * not result in wasted space in the SAL xp_addr_region table because
 519          * we should get the same page for remote_amos_page_pa after module
 520          * reloads and system reboots.
 521          */
 522         if (sn_register_xp_addr_region(part->remote_amos_page_pa,
 523                                                         PAGE_SIZE, 1) < 0) {
 524                 dev_warn(xpc_part, "xpc_partition_up(%d) failed to register "
 525                         "xp_addr region\n", partid);
 526
 527                 spin_lock_irqsave(&part->act_lock, irq_flags);
 528                 part->act_state = XPC_P_INACTIVE;
 529                 XPC_SET_REASON(part, xpcPhysAddrRegFailed, __LINE__);
 530                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 531                 part->remote_rp_pa = 0;
 532                 return 0;
 533         }
 534
 535         xpc_allow_hb(partid, xpc_vars);
 536         xpc_IPI_send_activated(part);
 537
 538
 539         /*
 540          * xpc_partition_up() holds this thread and marks this partition as
 541          * XPC_P_ACTIVE by calling xpc_hb_mark_active().
 542          */
 543         (void) xpc_partition_up(part);
 544
 545         xpc_disallow_hb(partid, xpc_vars);
 546         xpc_mark_partition_inactive(part);
 547
 548         if (part->reason == xpcReactivating) {
 549                 /* interrupting ourselves results in activating partition */
 550                 xpc_IPI_send_reactivate(part);
 551         }
 552
 553         return 0;
 554 }
 555
 556
 557 void
 558 xpc_activate_partition(struct xpc_partition *part)
 559 {
 560         partid_t partid = XPC_PARTID(part);
 561         unsigned long irq_flags;
 562         pid_t pid;
 563
 564
 565         spin_lock_irqsave(&part->act_lock, irq_flags);
 566
 567         DBUG_ON(part->act_state != XPC_P_INACTIVE);
 568
 569         part->act_state = XPC_P_ACTIVATION_REQ;
 570         XPC_SET_REASON(part, xpcCloneKThread, __LINE__);
 571
 572         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 573
 574         pid = kernel_thread(xpc_activating, (void *) ((u64) partid), 0);
 575
 576         if (unlikely(pid <= 0)) {
 577                 spin_lock_irqsave(&part->act_lock, irq_flags);
 578                 part->act_state = XPC_P_INACTIVE;
 579                 XPC_SET_REASON(part, xpcCloneKThreadFailed, __LINE__);
 580                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 581         }
 582 }
 583
 584
 585 /*
 586  * Handle the receipt of a SGI_XPC_NOTIFY IRQ by seeing whether the specified
 587  * partition actually sent it. Since SGI_XPC_NOTIFY IRQs may be shared by more
 588  * than one partition, we use an AMO_t structure per partition to indicate
 589  * whether a partition has sent an IPI or not.  >>> If it has, then wake up the
 590  * associated kthread to handle it.
 591  *
 592  * All SGI_XPC_NOTIFY IRQs received by XPC are the result of IPIs sent by XPC
 593  * running on other partitions.
 594  *
 595  * Noteworthy Arguments:
 596  *
 597  *      irq - Interrupt ReQuest number. NOT USED.
 598  *
 599  *      dev_id - partid of IPI's potential sender.
 600  */
 601 irqreturn_t
 602 xpc_notify_IRQ_handler(int irq, void *dev_id)
 603 {
 604         partid_t partid = (partid_t) (u64) dev_id;
 605         struct xpc_partition *part = &xpc_partitions[partid];
 606
 607
 608         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
 609
 610         if (xpc_part_ref(part)) {
 611                 xpc_check_for_channel_activity(part);
 612
 613                 xpc_part_deref(part);
 614         }
 615         return IRQ_HANDLED;
 616 }
 617
 618
 619 /*
 620  * Check to see if xpc_notify_IRQ_handler() dropped any IPIs on the floor
 621  * because the write to their associated IPI amo completed after the IRQ/IPI
 622  * was received.
 623  */
 624 void
 625 xpc_dropped_IPI_check(struct xpc_partition *part)
 626 {
 627         if (xpc_part_ref(part)) {
 628                 xpc_check_for_channel_activity(part);
 629
 630                 part->dropped_IPI_timer.expires = jiffies +
 631                                                         XPC_P_DROPPED_IPI_WAIT;
 632                 add_timer(&part->dropped_IPI_timer);
 633                 xpc_part_deref(part);
 634         }
 635 }
 636
 637
 638 void
 639 xpc_activate_kthreads(struct xpc_channel *ch, int needed)
 640 {
 641         int idle = atomic_read(&ch->kthreads_idle);
 642         int assigned = atomic_read(&ch->kthreads_assigned);
 643         int wakeup;
 644
 645
 646         DBUG_ON(needed <= 0);
 647
 648         if (idle > 0) {
 649                 wakeup = (needed > idle) ? idle : needed;
 650                 needed -= wakeup;
 651
 652                 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
 653                         "channel=%d\n", wakeup, ch->partid, ch->number);
 654
 655                 /* only wakeup the requested number of kthreads */
 656                 wake_up_nr(&ch->idle_wq, wakeup);
 657         }
 658
 659         if (needed <= 0) {
 660                 return;
 661         }
 662
 663         if (needed + assigned > ch->kthreads_assigned_limit) {
 664                 needed = ch->kthreads_assigned_limit - assigned;
 665                 // >>>should never be less than 0
 666                 if (needed <= 0) {
 667                         return;
 668                 }
 669         }
 670
 671         dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
 672                 needed, ch->partid, ch->number);
 673
 674         xpc_create_kthreads(ch, needed, 0);
 675 }
 676
 677
 678 /*
 679  * This function is where XPC's kthreads wait for messages to deliver.
 680  */
 681 static void
 682 xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
 683 {
 684         do {
 685                 /* deliver messages to their intended recipients */
 686
 687                 while ((volatile s64) ch->w_local_GP.get <
 688                                 (volatile s64) ch->w_remote_GP.put &&
 689                                         !((volatile u32) ch->flags &
 690                                                 XPC_C_DISCONNECTING)) {
 691                         xpc_deliver_msg(ch);
 692                 }
 693
 694                 if (atomic_inc_return(&ch->kthreads_idle) >
 695                                                 ch->kthreads_idle_limit) {
 696                         /* too many idle kthreads on this channel */
 697                         atomic_dec(&ch->kthreads_idle);
 698                         break;
 699                 }
 700
 701                 dev_dbg(xpc_chan, "idle kthread calling "
 702                         "wait_event_interruptible_exclusive()\n");
 703
 704                 (void) wait_event_interruptible_exclusive(ch->idle_wq,
 705                                 ((volatile s64) ch->w_local_GP.get <
 706                                         (volatile s64) ch->w_remote_GP.put ||
 707                                 ((volatile u32) ch->flags &
 708                                                 XPC_C_DISCONNECTING)));
 709
 710                 atomic_dec(&ch->kthreads_idle);
 711
 712         } while (!((volatile u32) ch->flags & XPC_C_DISCONNECTING));
 713 }
 714
 715
 716 static int
 717 xpc_daemonize_kthread(void *args)
 718 {
 719         partid_t partid = XPC_UNPACK_ARG1(args);
 720         u16 ch_number = XPC_UNPACK_ARG2(args);
 721         struct xpc_partition *part = &xpc_partitions[partid];
 722         struct xpc_channel *ch;
 723         int n_needed;
 724         unsigned long irq_flags;
 725
 726
 727         daemonize("xpc%02dc%d", partid, ch_number);
 728
 729         dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
 730                 partid, ch_number);
 731
 732         ch = &part->channels[ch_number];
 733
 734         if (!(ch->flags & XPC_C_DISCONNECTING)) {
 735
 736                 /* let registerer know that connection has been established */
 737
 738                 spin_lock_irqsave(&ch->lock, irq_flags);
 739                 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
 740                         ch->flags |= XPC_C_CONNECTEDCALLOUT;
 741                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 742
 743                         xpc_connected_callout(ch);
 744
 745                         spin_lock_irqsave(&ch->lock, irq_flags);
 746                         ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
 747                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 748
 749                         /*
 750                          * It is possible that while the callout was being
 751                          * made that the remote partition sent some messages.
 752                          * If that is the case, we may need to activate
 753                          * additional kthreads to help deliver them. We only
 754                          * need one less than total #of messages to deliver.
 755                          */
 756                         n_needed = ch->w_remote_GP.put - ch->w_local_GP.get - 1;
 757                         if (n_needed > 0 &&
 758                                         !(ch->flags & XPC_C_DISCONNECTING)) {
 759                                 xpc_activate_kthreads(ch, n_needed);
 760                         }
 761                 } else {
 762                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 763                 }
 764
 765                 xpc_kthread_waitmsgs(part, ch);
 766         }
 767
 768         /* let registerer know that connection is disconnecting */
 769
 770         spin_lock_irqsave(&ch->lock, irq_flags);
 771         if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
 772                         !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
 773                 ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
 774                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 775
 776                 xpc_disconnect_callout(ch, xpcDisconnecting);
 777
 778                 spin_lock_irqsave(&ch->lock, irq_flags);
 779                 ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
 780         }
 781         spin_unlock_irqrestore(&ch->lock, irq_flags);
 782
 783         if (atomic_dec_return(&ch->kthreads_assigned) == 0) {
 784                 if (atomic_dec_return(&part->nchannels_engaged) == 0) {
 785                         xpc_mark_partition_disengaged(part);
 786                         xpc_IPI_send_disengage(part);
 787                 }
 788         }
 789
 790         xpc_msgqueue_deref(ch);
 791
 792         dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
 793                 partid, ch_number);
 794
 795         xpc_part_deref(part);
 796         return 0;
 797 }
 798
 799
 800 /*
 801  * For each partition that XPC has established communications with, there is
 802  * a minimum of one kernel thread assigned to perform any operation that
 803  * may potentially sleep or block (basically the callouts to the asynchronous
 804  * functions registered via xpc_connect()).
 805  *
 806  * Additional kthreads are created and destroyed by XPC as the workload
 807  * demands.
 808  *
 809  * A kthread is assigned to one of the active channels that exists for a given
 810  * partition.
 811  */
 812 void
 813 xpc_create_kthreads(struct xpc_channel *ch, int needed,
 814                         int ignore_disconnecting)
 815 {
 816         unsigned long irq_flags;
 817         pid_t pid;
 818         u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
 819         struct xpc_partition *part = &xpc_partitions[ch->partid];
 820
 821
 822         while (needed-- > 0) {
 823
 824                 /*
 825                  * The following is done on behalf of the newly created
 826                  * kthread. That kthread is responsible for doing the
 827                  * counterpart to the following before it exits.
 828                  */
 829                 if (ignore_disconnecting) {
 830                         if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
 831                                 /* kthreads assigned had gone to zero */
 832                                 BUG_ON(!(ch->flags &
 833                                         XPC_C_DISCONNECTINGCALLOUT_MADE));
 834                                 break;
 835                         }
 836
 837                 } else if (ch->flags & XPC_C_DISCONNECTING) {
 838                         break;
 839
 840                 } else if (atomic_inc_return(&ch->kthreads_assigned) == 1) {
 841                         if (atomic_inc_return(&part->nchannels_engaged) == 1)
 842                                 xpc_mark_partition_engaged(part);
 843                 }
 844                 (void) xpc_part_ref(part);
 845                 xpc_msgqueue_ref(ch);
 846
 847                 pid = kernel_thread(xpc_daemonize_kthread, (void *) args, 0);
 848                 if (pid < 0) {
 849                         /* the fork failed */
 850
 851                         /*
 852                          * NOTE: if (ignore_disconnecting &&
 853                          * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
 854                          * then we'll deadlock if all other kthreads assigned
 855                          * to this channel are blocked in the channel's
 856                          * registerer, because the only thing that will unblock
 857                          * them is the xpcDisconnecting callout that this
 858                          * failed kernel_thread would have made.
 859                          */
 860
 861                         if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 862                             atomic_dec_return(&part->nchannels_engaged) == 0) {
 863                                 xpc_mark_partition_disengaged(part);
 864                                 xpc_IPI_send_disengage(part);
 865                         }
 866                         xpc_msgqueue_deref(ch);
 867                         xpc_part_deref(part);
 868
 869                         if (atomic_read(&ch->kthreads_assigned) <
 870                                                 ch->kthreads_idle_limit) {
 871                                 /*
 872                                  * Flag this as an error only if we have an
 873                                  * insufficient #of kthreads for the channel
 874                                  * to function.
 875                                  */
 876                                 spin_lock_irqsave(&ch->lock, irq_flags);
 877                                 XPC_DISCONNECT_CHANNEL(ch, xpcLackOfResources,
 878                                                                 &irq_flags);
 879                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 880                         }
 881                         break;
 882                 }
 883
 884                 ch->kthreads_created++; // >>> temporary debug only!!!
 885         }
 886 }
 887
 888
 889 void
 890 xpc_disconnect_wait(int ch_number)
 891 {
 892         unsigned long irq_flags;
 893         partid_t partid;
 894         struct xpc_partition *part;
 895         struct xpc_channel *ch;
 896         int wakeup_channel_mgr;
 897
 898
 899         /* now wait for all callouts to the caller's function to cease */
 900         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
 901                 part = &xpc_partitions[partid];
 902
 903                 if (!xpc_part_ref(part)) {
 904                         continue;
 905                 }
 906
 907                 ch = &part->channels[ch_number];
 908
 909                 if (!(ch->flags & XPC_C_WDISCONNECT)) {
 910                         xpc_part_deref(part);
 911                         continue;
 912                 }
 913
 914                 wait_for_completion(&ch->wdisconnect_wait);
 915
 916                 spin_lock_irqsave(&ch->lock, irq_flags);
 917                 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
 918                 wakeup_channel_mgr = 0;
 919
 920                 if (ch->delayed_IPI_flags) {
 921                         if (part->act_state != XPC_P_DEACTIVATING) {
 922                                 spin_lock(&part->IPI_lock);
 923                                 XPC_SET_IPI_FLAGS(part->local_IPI_amo,
 924                                         ch->number, ch->delayed_IPI_flags);
 925                                 spin_unlock(&part->IPI_lock);
 926                                 wakeup_channel_mgr = 1;
 927                         }
 928                         ch->delayed_IPI_flags = 0;
 929                 }
 930
 931                 ch->flags &= ~XPC_C_WDISCONNECT;
 932                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 933
 934                 if (wakeup_channel_mgr) {
 935                         xpc_wakeup_channel_mgr(part);
 936                 }
 937
 938                 xpc_part_deref(part);
 939         }
 940 }
 941
 942
 943 static void
 944 xpc_do_exit(enum xpc_retval reason)
 945 {
 946         partid_t partid;
 947         int active_part_count, printed_waiting_msg = 0;
 948         struct xpc_partition *part;
 949         unsigned long printmsg_time, disengage_request_timeout = 0;
 950
 951
 952         /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
 953         DBUG_ON(xpc_exiting == 1);
 954
 955         /*
 956          * Let the heartbeat checker thread and the discovery thread
 957          * (if one is running) know that they should exit. Also wake up
 958          * the heartbeat checker thread in case it's sleeping.
 959          */
 960         xpc_exiting = 1;
 961         wake_up_interruptible(&xpc_act_IRQ_wq);
 962
 963         /* ignore all incoming interrupts */
 964         free_irq(SGI_XPC_ACTIVATE, NULL);
 965
 966         /* wait for the discovery thread to exit */
 967         wait_for_completion(&xpc_discovery_exited);
 968
 969         /* wait for the heartbeat checker thread to exit */
 970         wait_for_completion(&xpc_hb_checker_exited);
 971
 972
 973         /* sleep for a 1/3 of a second or so */
 974         (void) msleep_interruptible(300);
 975
 976
 977         /* wait for all partitions to become inactive */
 978
 979         printmsg_time = jiffies + (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
 980         xpc_disengage_request_timedout = 0;
 981
 982         do {
 983                 active_part_count = 0;
 984
 985                 for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
 986                         part = &xpc_partitions[partid];
 987
 988                         if (xpc_partition_disengaged(part) &&
 989                                         part->act_state == XPC_P_INACTIVE) {
 990                                 continue;
 991                         }
 992
 993                         active_part_count++;
 994
 995                         XPC_DEACTIVATE_PARTITION(part, reason);
 996
 997                         if (part->disengage_request_timeout >
 998                                                 disengage_request_timeout) {
 999                                 disengage_request_timeout =
1000                                                 part->disengage_request_timeout;
1001                         }
1002                 }
1003
1004                 if (xpc_partition_engaged(-1UL)) {
1005                         if (time_after(jiffies, printmsg_time)) {
1006                                 dev_info(xpc_part, "waiting for remote "
1007                                         "partitions to disengage, timeout in "
1008                                         "%ld seconds\n",
1009                                         (disengage_request_timeout - jiffies)
1010                                                                         / HZ);
1011                                 printmsg_time = jiffies +
1012                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
1013                                 printed_waiting_msg = 1;
1014                         }
1015
1016                 } else if (active_part_count > 0) {
1017                         if (printed_waiting_msg) {
1018                                 dev_info(xpc_part, "waiting for local partition"
1019                                         " to disengage\n");
1020                                 printed_waiting_msg = 0;
1021                         }
1022
1023                 } else {
1024                         if (!xpc_disengage_request_timedout) {
1025                                 dev_info(xpc_part, "all partitions have "
1026                                         "disengaged\n");
1027                         }
1028                         break;
1029                 }
1030
1031                 /* sleep for a 1/3 of a second or so */
1032                 (void) msleep_interruptible(300);
1033
1034         } while (1);
1035
1036         DBUG_ON(xpc_partition_engaged(-1UL));
1037
1038
1039         /* indicate to others that our reserved page is uninitialized */
1040         xpc_rsvd_page->vars_pa = 0;
1041
1042         /* now it's time to eliminate our heartbeat */
1043         del_timer_sync(&xpc_hb_timer);
1044         DBUG_ON(xpc_vars->heartbeating_to_mask != 0);
1045
1046         if (reason == xpcUnloading) {
1047                 /* take ourselves off of the reboot_notifier_list */
1048                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1049
1050                 /* take ourselves off of the die_notifier list */
1051                 (void) unregister_die_notifier(&xpc_die_notifier);
1052         }
1053
1054         /* close down protections for IPI operations */
1055         xpc_restrict_IPI_ops();
1056
1057
1058         /* clear the interface to XPC's functions */
1059         xpc_clear_interface();
1060
1061         if (xpc_sysctl) {
1062                 unregister_sysctl_table(xpc_sysctl);
1063         }
1064
1065         kfree(xpc_remote_copy_buffer_base);
1066 }
1067
1068
1069 /*
1070  * This function is called when the system is being rebooted.
1071  */
1072 static int
1073 xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1074 {
1075         enum xpc_retval reason;
1076
1077
1078         switch (event) {
1079         case SYS_RESTART:
1080                 reason = xpcSystemReboot;
1081                 break;
1082         case SYS_HALT:
1083                 reason = xpcSystemHalt;
1084                 break;
1085         case SYS_POWER_OFF:
1086                 reason = xpcSystemPoweroff;
1087                 break;
1088         default:
1089                 reason = xpcSystemGoingDown;
1090         }
1091
1092         xpc_do_exit(reason);
1093         return NOTIFY_DONE;
1094 }
1095
1096
1097 /*
1098  * Notify other partitions to disengage from all references to our memory.
1099  */
1100 static void
1101 xpc_die_disengage(void)
1102 {
1103         struct xpc_partition *part;
1104         partid_t partid;
1105         unsigned long engaged;
1106         long time, printmsg_time, disengage_request_timeout;
1107
1108
1109         /* keep xpc_hb_checker thread from doing anything (just in case) */
1110         xpc_exiting = 1;
1111
1112         xpc_vars->heartbeating_to_mask = 0;  /* indicate we're deactivated */
1113
1114         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1115                 part = &xpc_partitions[partid];
1116
1117                 if (!XPC_SUPPORTS_DISENGAGE_REQUEST(part->
1118                                                         remote_vars_version)) {
1119
1120                         /* just in case it was left set by an earlier XPC */
1121                         xpc_clear_partition_engaged(1UL << partid);
1122                         continue;
1123                 }
1124
1125                 if (xpc_partition_engaged(1UL << partid) ||
1126                                         part->act_state != XPC_P_INACTIVE) {
1127                         xpc_request_partition_disengage(part);
1128                         xpc_mark_partition_disengaged(part);
1129                         xpc_IPI_send_disengage(part);
1130                 }
1131         }
1132
1133         time = rtc_time();
1134         printmsg_time = time +
1135                 (XPC_DISENGAGE_PRINTMSG_INTERVAL * sn_rtc_cycles_per_second);
1136         disengage_request_timeout = time +
1137                 (xpc_disengage_request_timelimit * sn_rtc_cycles_per_second);
1138
1139         /* wait for all other partitions to disengage from us */
1140
1141         while (1) {
1142                 engaged = xpc_partition_engaged(-1UL);
1143                 if (!engaged) {
1144                         dev_info(xpc_part, "all partitions have disengaged\n");
1145                         break;
1146                 }
1147
1148                 time = rtc_time();
1149                 if (time >= disengage_request_timeout) {
1150                         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1151                                 if (engaged & (1UL << partid)) {
1152                                         dev_info(xpc_part, "disengage from "
1153                                                 "remote partition %d timed "
1154                                                 "out\n", partid);
1155                                 }
1156                         }
1157                         break;
1158                 }
1159
1160                 if (time >= printmsg_time) {
1161                         dev_info(xpc_part, "waiting for remote partitions to "
1162                                 "disengage, timeout in %ld seconds\n",
1163                                 (disengage_request_timeout - time) /
1164                                                 sn_rtc_cycles_per_second);
1165                         printmsg_time = time +
1166                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL *
1167                                                 sn_rtc_cycles_per_second);
1168                 }
1169         }
1170 }
1171
1172
1173 /*
1174  * This function is called when the system is being restarted or halted due
1175  * to some sort of system failure. If this is the case we need to notify the
1176  * other partitions to disengage from all references to our memory.
1177  * This function can also be called when our heartbeater could be offlined
1178  * for a time. In this case we need to notify other partitions to not worry
1179  * about the lack of a heartbeat.
1180  */
1181 static int
1182 xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1183 {
1184         switch (event) {
1185         case DIE_MACHINE_RESTART:
1186         case DIE_MACHINE_HALT:
1187                 xpc_die_disengage();
1188                 break;
1189
1190         case DIE_KDEBUG_ENTER:
1191                 /* Should lack of heartbeat be ignored by other partitions? */
1192                 if (!xpc_kdebug_ignore) {
1193                         break;
1194                 }
1195                 /* fall through */
1196         case DIE_MCA_MONARCH_ENTER:
1197         case DIE_INIT_MONARCH_ENTER:
1198                 xpc_vars->heartbeat++;
1199                 xpc_vars->heartbeat_offline = 1;
1200                 break;
1201
1202         case DIE_KDEBUG_LEAVE:
1203                 /* Is lack of heartbeat being ignored by other partitions? */
1204                 if (!xpc_kdebug_ignore) {
1205                         break;
1206                 }
1207                 /* fall through */
1208         case DIE_MCA_MONARCH_LEAVE:
1209         case DIE_INIT_MONARCH_LEAVE:
1210                 xpc_vars->heartbeat++;
1211                 xpc_vars->heartbeat_offline = 0;
1212                 break;
1213         }
1214
1215         return NOTIFY_DONE;
1216 }
1217
1218
1219 int __init
1220 xpc_init(void)
1221 {
1222         int ret;
1223         partid_t partid;
1224         struct xpc_partition *part;
1225         pid_t pid;
1226         size_t buf_size;
1227
1228
1229         if (!ia64_platform_is("sn2")) {
1230                 return -ENODEV;
1231         }
1232
1233
1234         buf_size = max(XPC_RP_VARS_SIZE,
1235                                 XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES);
1236         xpc_remote_copy_buffer = xpc_kmalloc_cacheline_aligned(buf_size,
1237                                      GFP_KERNEL, &xpc_remote_copy_buffer_base);
1238         if (xpc_remote_copy_buffer == NULL)
1239                 return -ENOMEM;
1240
1241         snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
1242         snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
1243
1244         xpc_sysctl = register_sysctl_table(xpc_sys_dir);
1245
1246         /*
1247          * The first few fields of each entry of xpc_partitions[] need to
1248          * be initialized now so that calls to xpc_connect() and
1249          * xpc_disconnect() can be made prior to the activation of any remote
1250          * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
1251          * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
1252          * PARTITION HAS BEEN ACTIVATED.
1253          */
1254         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1255                 part = &xpc_partitions[partid];
1256
1257                 DBUG_ON((u64) part != L1_CACHE_ALIGN((u64) part));
1258
1259                 part->act_IRQ_rcvd = 0;
1260                 spin_lock_init(&part->act_lock);
1261                 part->act_state = XPC_P_INACTIVE;
1262                 XPC_SET_REASON(part, 0, 0);
1263
1264                 init_timer(&part->disengage_request_timer);
1265                 part->disengage_request_timer.function =
1266                                 xpc_timeout_partition_disengage_request;
1267                 part->disengage_request_timer.data = (unsigned long) part;
1268
1269                 part->setup_state = XPC_P_UNSET;
1270                 init_waitqueue_head(&part->teardown_wq);
1271                 atomic_set(&part->references, 0);
1272         }
1273
1274         /*
1275          * Open up protections for IPI operations (and AMO operations on
1276          * Shub 1.1 systems).
1277          */
1278         xpc_allow_IPI_ops();
1279
1280         /*
1281          * Interrupts being processed will increment this atomic variable and
1282          * awaken the heartbeat thread which will process the interrupts.
1283          */
1284         atomic_set(&xpc_act_IRQ_rcvd, 0);
1285
1286         /*
1287          * This is safe to do before the xpc_hb_checker thread has started
1288          * because the handler releases a wait queue.  If an interrupt is
1289          * received before the thread is waiting, it will not go to sleep,
1290          * but rather immediately process the interrupt.
1291          */
1292         ret = request_irq(SGI_XPC_ACTIVATE, xpc_act_IRQ_handler, 0,
1293                                                         "xpc hb", NULL);
1294         if (ret != 0) {
1295                 dev_err(xpc_part, "can't register ACTIVATE IRQ handler, "
1296                         "errno=%d\n", -ret);
1297
1298                 xpc_restrict_IPI_ops();
1299
1300                 if (xpc_sysctl) {
1301                         unregister_sysctl_table(xpc_sysctl);
1302                 }
1303
1304                 kfree(xpc_remote_copy_buffer_base);
1305                 return -EBUSY;
1306         }
1307
1308         /*
1309          * Fill the partition reserved page with the information needed by
1310          * other partitions to discover we are alive and establish initial
1311          * communications.
1312          */
1313         xpc_rsvd_page = xpc_rsvd_page_init();
1314         if (xpc_rsvd_page == NULL) {
1315                 dev_err(xpc_part, "could not setup our reserved page\n");
1316
1317                 free_irq(SGI_XPC_ACTIVATE, NULL);
1318                 xpc_restrict_IPI_ops();
1319
1320                 if (xpc_sysctl) {
1321                         unregister_sysctl_table(xpc_sysctl);
1322                 }
1323
1324                 kfree(xpc_remote_copy_buffer_base);
1325                 return -EBUSY;
1326         }
1327
1328
1329         /* add ourselves to the reboot_notifier_list */
1330         ret = register_reboot_notifier(&xpc_reboot_notifier);
1331         if (ret != 0) {
1332                 dev_warn(xpc_part, "can't register reboot notifier\n");
1333         }
1334
1335         /* add ourselves to the die_notifier list (i.e., ia64die_chain) */
1336         ret = register_die_notifier(&xpc_die_notifier);
1337         if (ret != 0) {
1338                 dev_warn(xpc_part, "can't register die notifier\n");
1339         }
1340
1341
1342         /*
1343          * Set the beating to other partitions into motion.  This is
1344          * the last requirement for other partitions' discovery to
1345          * initiate communications with us.
1346          */
1347         init_timer(&xpc_hb_timer);
1348         xpc_hb_timer.function = xpc_hb_beater;
1349         xpc_hb_beater(0);
1350
1351
1352         /*
1353          * The real work-horse behind xpc.  This processes incoming
1354          * interrupts and monitors remote heartbeats.
1355          */
1356         pid = kernel_thread(xpc_hb_checker, NULL, 0);
1357         if (pid < 0) {
1358                 dev_err(xpc_part, "failed while forking hb check thread\n");
1359
1360                 /* indicate to others that our reserved page is uninitialized */
1361                 xpc_rsvd_page->vars_pa = 0;
1362
1363                 /* take ourselves off of the reboot_notifier_list */
1364                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1365
1366                 /* take ourselves off of the die_notifier list */
1367                 (void) unregister_die_notifier(&xpc_die_notifier);
1368
1369                 del_timer_sync(&xpc_hb_timer);
1370                 free_irq(SGI_XPC_ACTIVATE, NULL);
1371                 xpc_restrict_IPI_ops();
1372
1373                 if (xpc_sysctl) {
1374                         unregister_sysctl_table(xpc_sysctl);
1375                 }
1376
1377                 kfree(xpc_remote_copy_buffer_base);
1378                 return -EBUSY;
1379         }
1380
1381
1382         /*
1383          * Startup a thread that will attempt to discover other partitions to
1384          * activate based on info provided by SAL. This new thread is short
1385          * lived and will exit once discovery is complete.
1386          */
1387         pid = kernel_thread(xpc_initiate_discovery, NULL, 0);
1388         if (pid < 0) {
1389                 dev_err(xpc_part, "failed while forking discovery thread\n");
1390
1391                 /* mark this new thread as a non-starter */
1392                 complete(&xpc_discovery_exited);
1393
1394                 xpc_do_exit(xpcUnloading);
1395                 return -EBUSY;
1396         }
1397
1398
1399         /* set the interface to point at XPC's functions */
1400         xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1401                           xpc_initiate_allocate, xpc_initiate_send,
1402                           xpc_initiate_send_notify, xpc_initiate_received,
1403                           xpc_initiate_partid_to_nasids);
1404
1405         return 0;
1406 }
1407 module_init(xpc_init);
1408
1409
1410 void __exit
1411 xpc_exit(void)
1412 {
1413         xpc_do_exit(xpcUnloading);
1414 }
1415 module_exit(xpc_exit);
1416
1417
1418 MODULE_AUTHOR("Silicon Graphics, Inc.");
1419 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1420 MODULE_LICENSE("GPL");
1421
1422 module_param(xpc_hb_interval, int, 0);
1423 MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1424                 "heartbeat increments.");
1425
1426 module_param(xpc_hb_check_interval, int, 0);
1427 MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1428                 "heartbeat checks.");
1429
1430 module_param(xpc_disengage_request_timelimit, int, 0);
1431 MODULE_PARM_DESC(xpc_disengage_request_timelimit, "Number of seconds to wait "
1432                 "for disengage request to complete.");
1433
1434 module_param(xpc_kdebug_ignore, int, 0);
1435 MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1436                 "other partitions when dropping into kdebug.");
1437