drivers/misc/sgi-xp/xpc_main.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   8
   9 /*
  10  * Cross Partition Communication (XPC) support - standard version.
  11  *
  12  *      XPC provides a message passing capability that crosses partition
  13  *      boundaries. This module is made up of two parts:
  14  *
  15  *          partition   This part detects the presence/absence of other
  16  *                      partitions. It provides a heartbeat and monitors
  17  *                      the heartbeats of other partitions.
  18  *
  19  *          channel     This part manages the channels and sends/receives
  20  *                      messages across them to/from other partitions.
  21  *
  22  *      There are a couple of additional functions residing in XP, which
  23  *      provide an interface to XPC for its users.
  24  *
  25  *
  26  *      Caveats:
  27  *
  28  *        . Currently on sn2, we have no way to determine which nasid an IRQ
  29  *          came from. Thus, xpc_send_IRQ_sn2() does a remote amo write
  30  *          followed by an IPI. The amo indicates where data is to be pulled
  31  *          from, so after the IPI arrives, the remote partition checks the amo
  32  *          word. The IPI can actually arrive before the amo however, so other
  33  *          code must periodically check for this case. Also, remote amo
  34  *          operations do not reliably time out. Thus we do a remote PIO read
  35  *          solely to know whether the remote partition is down and whether we
  36  *          should stop sending IPIs to it. This remote PIO read operation is
  37  *          set up in a special nofault region so SAL knows to ignore (and
  38  *          cleanup) any errors due to the remote amo write, PIO read, and/or
  39  *          PIO write operations.
  40  *
  41  *          If/when new hardware solves this IPI problem, we should abandon
  42  *          the current approach.
  43  *
  44  */
  45
  46 #include <linux/module.h>
  47 #include <linux/sysctl.h>
  48 #include <linux/device.h>
  49 #include <linux/delay.h>
  50 #include <linux/reboot.h>
  51 #include <linux/kdebug.h>
  52 #include <linux/kthread.h>
  53 #include "xpc.h"
  54
  55 /* define two XPC debug device structures to be used with dev_dbg() et al */
  56
  57 struct device_driver xpc_dbg_name = {
  58         .name = "xpc"
  59 };
  60
  61 struct device xpc_part_dbg_subname = {
  62         .init_name = "",        /* set to "part" at xpc_init() time */
  63         .driver = &xpc_dbg_name
  64 };
  65
  66 struct device xpc_chan_dbg_subname = {
  67         .init_name = "",        /* set to "chan" at xpc_init() time */
  68         .driver = &xpc_dbg_name
  69 };
  70
  71 struct device *xpc_part = &xpc_part_dbg_subname;
  72 struct device *xpc_chan = &xpc_chan_dbg_subname;
  73
  74 static int xpc_kdebug_ignore;
  75
  76 /* systune related variables for /proc/sys directories */
  77
  78 static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
  79 static int xpc_hb_min_interval = 1;
  80 static int xpc_hb_max_interval = 10;
  81
  82 static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
  83 static int xpc_hb_check_min_interval = 10;
  84 static int xpc_hb_check_max_interval = 120;
  85
  86 int xpc_disengage_timelimit = XPC_DISENGAGE_DEFAULT_TIMELIMIT;
  87 static int xpc_disengage_min_timelimit; /* = 0 */
  88 static int xpc_disengage_max_timelimit = 120;
  89
  90 static ctl_table xpc_sys_xpc_hb_dir[] = {
  91         {
  92          .ctl_name = CTL_UNNUMBERED,
  93          .procname = "hb_interval",
  94          .data = &xpc_hb_interval,
  95          .maxlen = sizeof(int),
  96          .mode = 0644,
  97          .proc_handler = &proc_dointvec_minmax,
  98          .strategy = &sysctl_intvec,
  99          .extra1 = &xpc_hb_min_interval,
 100          .extra2 = &xpc_hb_max_interval},
 101         {
 102          .ctl_name = CTL_UNNUMBERED,
 103          .procname = "hb_check_interval",
 104          .data = &xpc_hb_check_interval,
 105          .maxlen = sizeof(int),
 106          .mode = 0644,
 107          .proc_handler = &proc_dointvec_minmax,
 108          .strategy = &sysctl_intvec,
 109          .extra1 = &xpc_hb_check_min_interval,
 110          .extra2 = &xpc_hb_check_max_interval},
 111         {}
 112 };
 113 static ctl_table xpc_sys_xpc_dir[] = {
 114         {
 115          .ctl_name = CTL_UNNUMBERED,
 116          .procname = "hb",
 117          .mode = 0555,
 118          .child = xpc_sys_xpc_hb_dir},
 119         {
 120          .ctl_name = CTL_UNNUMBERED,
 121          .procname = "disengage_timelimit",
 122          .data = &xpc_disengage_timelimit,
 123          .maxlen = sizeof(int),
 124          .mode = 0644,
 125          .proc_handler = &proc_dointvec_minmax,
 126          .strategy = &sysctl_intvec,
 127          .extra1 = &xpc_disengage_min_timelimit,
 128          .extra2 = &xpc_disengage_max_timelimit},
 129         {}
 130 };
 131 static ctl_table xpc_sys_dir[] = {
 132         {
 133          .ctl_name = CTL_UNNUMBERED,
 134          .procname = "xpc",
 135          .mode = 0555,
 136          .child = xpc_sys_xpc_dir},
 137         {}
 138 };
 139 static struct ctl_table_header *xpc_sysctl;
 140
 141 /* non-zero if any remote partition disengage was timed out */
 142 int xpc_disengage_timedout;
 143
 144 /* #of activate IRQs received and not yet processed */
 145 int xpc_activate_IRQ_rcvd;
 146 DEFINE_SPINLOCK(xpc_activate_IRQ_rcvd_lock);
 147
 148 /* IRQ handler notifies this wait queue on receipt of an IRQ */
 149 DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq);
 150
 151 static unsigned long xpc_hb_check_timeout;
 152 static struct timer_list xpc_hb_timer;
 153 void *xpc_heartbeating_to_mask;
 154
 155 /* notification that the xpc_hb_checker thread has exited */
 156 static DECLARE_COMPLETION(xpc_hb_checker_exited);
 157
 158 /* notification that the xpc_discovery thread has exited */
 159 static DECLARE_COMPLETION(xpc_discovery_exited);
 160
 161 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
 162
 163 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
 164 static struct notifier_block xpc_reboot_notifier = {
 165         .notifier_call = xpc_system_reboot,
 166 };
 167
 168 static int xpc_system_die(struct notifier_block *, unsigned long, void *);
 169 static struct notifier_block xpc_die_notifier = {
 170         .notifier_call = xpc_system_die,
 171 };
 172
 173 int (*xpc_setup_partitions_sn) (void);
 174 enum xp_retval (*xpc_get_partition_rsvd_page_pa) (void *buf, u64 *cookie,
 175                                                   unsigned long *rp_pa,
 176                                                   size_t *len);
 177 int (*xpc_setup_rsvd_page_sn) (struct xpc_rsvd_page *rp);
 178 void (*xpc_heartbeat_init) (void);
 179 void (*xpc_heartbeat_exit) (void);
 180 void (*xpc_increment_heartbeat) (void);
 181 void (*xpc_offline_heartbeat) (void);
 182 void (*xpc_online_heartbeat) (void);
 183 enum xp_retval (*xpc_get_remote_heartbeat) (struct xpc_partition *part);
 184
 185 enum xp_retval (*xpc_make_first_contact) (struct xpc_partition *part);
 186 void (*xpc_notify_senders_of_disconnect) (struct xpc_channel *ch);
 187 u64 (*xpc_get_chctl_all_flags) (struct xpc_partition *part);
 188 enum xp_retval (*xpc_setup_msg_structures) (struct xpc_channel *ch);
 189 void (*xpc_teardown_msg_structures) (struct xpc_channel *ch);
 190 void (*xpc_process_msg_chctl_flags) (struct xpc_partition *part, int ch_number);
 191 int (*xpc_n_of_deliverable_payloads) (struct xpc_channel *ch);
 192 void *(*xpc_get_deliverable_payload) (struct xpc_channel *ch);
 193
 194 void (*xpc_request_partition_activation) (struct xpc_rsvd_page *remote_rp,
 195                                           unsigned long remote_rp_pa,
 196                                           int nasid);
 197 void (*xpc_request_partition_reactivation) (struct xpc_partition *part);
 198 void (*xpc_request_partition_deactivation) (struct xpc_partition *part);
 199 void (*xpc_cancel_partition_deactivation_request) (struct xpc_partition *part);
 200
 201 void (*xpc_process_activate_IRQ_rcvd) (void);
 202 enum xp_retval (*xpc_setup_ch_structures_sn) (struct xpc_partition *part);
 203 void (*xpc_teardown_ch_structures_sn) (struct xpc_partition *part);
 204
 205 void (*xpc_indicate_partition_engaged) (struct xpc_partition *part);
 206 int (*xpc_partition_engaged) (short partid);
 207 int (*xpc_any_partition_engaged) (void);
 208 void (*xpc_indicate_partition_disengaged) (struct xpc_partition *part);
 209 void (*xpc_assume_partition_disengaged) (short partid);
 210
 211 void (*xpc_send_chctl_closerequest) (struct xpc_channel *ch,
 212                                      unsigned long *irq_flags);
 213 void (*xpc_send_chctl_closereply) (struct xpc_channel *ch,
 214                                    unsigned long *irq_flags);
 215 void (*xpc_send_chctl_openrequest) (struct xpc_channel *ch,
 216                                     unsigned long *irq_flags);
 217 void (*xpc_send_chctl_openreply) (struct xpc_channel *ch,
 218                                   unsigned long *irq_flags);
 219
 220 void (*xpc_save_remote_msgqueue_pa) (struct xpc_channel *ch,
 221                                      unsigned long msgqueue_pa);
 222
 223 enum xp_retval (*xpc_send_payload) (struct xpc_channel *ch, u32 flags,
 224                                     void *payload, u16 payload_size,
 225                                     u8 notify_type, xpc_notify_func func,
 226                                     void *key);
 227 void (*xpc_received_payload) (struct xpc_channel *ch, void *payload);
 228
 229 /*
 230  * Timer function to enforce the timelimit on the partition disengage.
 231  */
 232 static void
 233 xpc_timeout_partition_disengage(unsigned long data)
 234 {
 235         struct xpc_partition *part = (struct xpc_partition *)data;
 236
 237         DBUG_ON(time_is_after_jiffies(part->disengage_timeout));
 238
 239         (void)xpc_partition_disengaged(part);
 240
 241         DBUG_ON(part->disengage_timeout != 0);
 242         DBUG_ON(xpc_partition_engaged(XPC_PARTID(part)));
 243 }
 244
 245 /*
 246  * Timer to produce the heartbeat.  The timer structures function is
 247  * already set when this is initially called.  A tunable is used to
 248  * specify when the next timeout should occur.
 249  */
 250 static void
 251 xpc_hb_beater(unsigned long dummy)
 252 {
 253         xpc_increment_heartbeat();
 254
 255         if (time_is_before_eq_jiffies(xpc_hb_check_timeout))
 256                 wake_up_interruptible(&xpc_activate_IRQ_wq);
 257
 258         xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
 259         add_timer(&xpc_hb_timer);
 260 }
 261
 262 static void
 263 xpc_start_hb_beater(void)
 264 {
 265         xpc_heartbeat_init();
 266         init_timer(&xpc_hb_timer);
 267         xpc_hb_timer.function = xpc_hb_beater;
 268         xpc_hb_beater(0);
 269 }
 270
 271 static void
 272 xpc_stop_hb_beater(void)
 273 {
 274         del_timer_sync(&xpc_hb_timer);
 275         xpc_heartbeat_exit();
 276 }
 277
 278 /*
 279  * At periodic intervals, scan through all active partitions and ensure
 280  * their heartbeat is still active.  If not, the partition is deactivated.
 281  */
 282 static void
 283 xpc_check_remote_hb(void)
 284 {
 285         struct xpc_partition *part;
 286         short partid;
 287         enum xp_retval ret;
 288
 289         for (partid = 0; partid < xp_max_npartitions; partid++) {
 290
 291                 if (xpc_exiting)
 292                         break;
 293
 294                 if (partid == xp_partition_id)
 295                         continue;
 296
 297                 part = &xpc_partitions[partid];
 298
 299                 if (part->act_state == XPC_P_AS_INACTIVE ||
 300                     part->act_state == XPC_P_AS_DEACTIVATING) {
 301                         continue;
 302                 }
 303
 304                 ret = xpc_get_remote_heartbeat(part);
 305                 if (ret != xpSuccess)
 306                         XPC_DEACTIVATE_PARTITION(part, ret);
 307         }
 308 }
 309
 310 /*
 311  * This thread is responsible for nearly all of the partition
 312  * activation/deactivation.
 313  */
 314 static int
 315 xpc_hb_checker(void *ignore)
 316 {
 317         int force_IRQ = 0;
 318
 319         /* this thread was marked active by xpc_hb_init() */
 320
 321         set_cpus_allowed_ptr(current, &cpumask_of_cpu(XPC_HB_CHECK_CPU));
 322
 323         /* set our heartbeating to other partitions into motion */
 324         xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
 325         xpc_start_hb_beater();
 326
 327         while (!xpc_exiting) {
 328
 329                 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
 330                         "been received\n",
 331                         (int)(xpc_hb_check_timeout - jiffies),
 332                         xpc_activate_IRQ_rcvd);
 333
 334                 /* checking of remote heartbeats is skewed by IRQ handling */
 335                 if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) {
 336                         xpc_hb_check_timeout = jiffies +
 337                             (xpc_hb_check_interval * HZ);
 338
 339                         dev_dbg(xpc_part, "checking remote heartbeats\n");
 340                         xpc_check_remote_hb();
 341
 342                         /*
 343                          * On sn2 we need to periodically recheck to ensure no
 344                          * IRQ/amo pairs have been missed.
 345                          */
 346                         if (is_shub())
 347                                 force_IRQ = 1;
 348                 }
 349
 350                 /* check for outstanding IRQs */
 351                 if (xpc_activate_IRQ_rcvd > 0 || force_IRQ != 0) {
 352                         force_IRQ = 0;
 353                         dev_dbg(xpc_part, "processing activate IRQs "
 354                                 "received\n");
 355                         xpc_process_activate_IRQ_rcvd();
 356                 }
 357
 358                 /* wait for IRQ or timeout */
 359                 (void)wait_event_interruptible(xpc_activate_IRQ_wq,
 360                                                (time_is_before_eq_jiffies(
 361                                                 xpc_hb_check_timeout) ||
 362                                                 xpc_activate_IRQ_rcvd > 0 ||
 363                                                 xpc_exiting));
 364         }
 365
 366         xpc_stop_hb_beater();
 367
 368         dev_dbg(xpc_part, "heartbeat checker is exiting\n");
 369
 370         /* mark this thread as having exited */
 371         complete(&xpc_hb_checker_exited);
 372         return 0;
 373 }
 374
 375 /*
 376  * This thread will attempt to discover other partitions to activate
 377  * based on info provided by SAL. This new thread is short lived and
 378  * will exit once discovery is complete.
 379  */
 380 static int
 381 xpc_initiate_discovery(void *ignore)
 382 {
 383         xpc_discovery();
 384
 385         dev_dbg(xpc_part, "discovery thread is exiting\n");
 386
 387         /* mark this thread as having exited */
 388         complete(&xpc_discovery_exited);
 389         return 0;
 390 }
 391
 392 /*
 393  * The first kthread assigned to a newly activated partition is the one
 394  * created by XPC HB with which it calls xpc_activating(). XPC hangs on to
 395  * that kthread until the partition is brought down, at which time that kthread
 396  * returns back to XPC HB. (The return of that kthread will signify to XPC HB
 397  * that XPC has dismantled all communication infrastructure for the associated
 398  * partition.) This kthread becomes the channel manager for that partition.
 399  *
 400  * Each active partition has a channel manager, who, besides connecting and
 401  * disconnecting channels, will ensure that each of the partition's connected
 402  * channels has the required number of assigned kthreads to get the work done.
 403  */
 404 static void
 405 xpc_channel_mgr(struct xpc_partition *part)
 406 {
 407         while (part->act_state != XPC_P_AS_DEACTIVATING ||
 408                atomic_read(&part->nchannels_active) > 0 ||
 409                !xpc_partition_disengaged(part)) {
 410
 411                 xpc_process_sent_chctl_flags(part);
 412
 413                 /*
 414                  * Wait until we've been requested to activate kthreads or
 415                  * all of the channel's message queues have been torn down or
 416                  * a signal is pending.
 417                  *
 418                  * The channel_mgr_requests is set to 1 after being awakened,
 419                  * This is done to prevent the channel mgr from making one pass
 420                  * through the loop for each request, since he will
 421                  * be servicing all the requests in one pass. The reason it's
 422                  * set to 1 instead of 0 is so that other kthreads will know
 423                  * that the channel mgr is running and won't bother trying to
 424                  * wake him up.
 425                  */
 426                 atomic_dec(&part->channel_mgr_requests);
 427                 (void)wait_event_interruptible(part->channel_mgr_wq,
 428                                 (atomic_read(&part->channel_mgr_requests) > 0 ||
 429                                  part->chctl.all_flags != 0 ||
 430                                  (part->act_state == XPC_P_AS_DEACTIVATING &&
 431                                  atomic_read(&part->nchannels_active) == 0 &&
 432                                  xpc_partition_disengaged(part))));
 433                 atomic_set(&part->channel_mgr_requests, 1);
 434         }
 435 }
 436
 437 /*
 438  * Guarantee that the kzalloc'd memory is cacheline aligned.
 439  */
 440 void *
 441 xpc_kzalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
 442 {
 443         /* see if kzalloc will give us cachline aligned memory by default */
 444         *base = kzalloc(size, flags);
 445         if (*base == NULL)
 446                 return NULL;
 447
 448         if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
 449                 return *base;
 450
 451         kfree(*base);
 452
 453         /* nope, we'll have to do it ourselves */
 454         *base = kzalloc(size + L1_CACHE_BYTES, flags);
 455         if (*base == NULL)
 456                 return NULL;
 457
 458         return (void *)L1_CACHE_ALIGN((u64)*base);
 459 }
 460
 461 /*
 462  * Setup the channel structures necessary to support XPartition Communication
 463  * between the specified remote partition and the local one.
 464  */
 465 static enum xp_retval
 466 xpc_setup_ch_structures(struct xpc_partition *part)
 467 {
 468         enum xp_retval ret;
 469         int ch_number;
 470         struct xpc_channel *ch;
 471         short partid = XPC_PARTID(part);
 472
 473         /*
 474          * Allocate all of the channel structures as a contiguous chunk of
 475          * memory.
 476          */
 477         DBUG_ON(part->channels != NULL);
 478         part->channels = kzalloc(sizeof(struct xpc_channel) * XPC_MAX_NCHANNELS,
 479                                  GFP_KERNEL);
 480         if (part->channels == NULL) {
 481                 dev_err(xpc_chan, "can't get memory for channels\n");
 482                 return xpNoMemory;
 483         }
 484
 485         /* allocate the remote open and close args */
 486
 487         part->remote_openclose_args =
 488             xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE,
 489                                           GFP_KERNEL, &part->
 490                                           remote_openclose_args_base);
 491         if (part->remote_openclose_args == NULL) {
 492                 dev_err(xpc_chan, "can't get memory for remote connect args\n");
 493                 ret = xpNoMemory;
 494                 goto out_1;
 495         }
 496
 497         part->chctl.all_flags = 0;
 498         spin_lock_init(&part->chctl_lock);
 499
 500         atomic_set(&part->channel_mgr_requests, 1);
 501         init_waitqueue_head(&part->channel_mgr_wq);
 502
 503         part->nchannels = XPC_MAX_NCHANNELS;
 504
 505         atomic_set(&part->nchannels_active, 0);
 506         atomic_set(&part->nchannels_engaged, 0);
 507
 508         for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
 509                 ch = &part->channels[ch_number];
 510
 511                 ch->partid = partid;
 512                 ch->number = ch_number;
 513                 ch->flags = XPC_C_DISCONNECTED;
 514
 515                 atomic_set(&ch->kthreads_assigned, 0);
 516                 atomic_set(&ch->kthreads_idle, 0);
 517                 atomic_set(&ch->kthreads_active, 0);
 518
 519                 atomic_set(&ch->references, 0);
 520                 atomic_set(&ch->n_to_notify, 0);
 521
 522                 spin_lock_init(&ch->lock);
 523                 init_completion(&ch->wdisconnect_wait);
 524
 525                 atomic_set(&ch->n_on_msg_allocate_wq, 0);
 526                 init_waitqueue_head(&ch->msg_allocate_wq);
 527                 init_waitqueue_head(&ch->idle_wq);
 528         }
 529
 530         ret = xpc_setup_ch_structures_sn(part);
 531         if (ret != xpSuccess)
 532                 goto out_2;
 533
 534         /*
 535          * With the setting of the partition setup_state to XPC_P_SS_SETUP,
 536          * we're declaring that this partition is ready to go.
 537          */
 538         part->setup_state = XPC_P_SS_SETUP;
 539
 540         return xpSuccess;
 541
 542         /* setup of ch structures failed */
 543 out_2:
 544         kfree(part->remote_openclose_args_base);
 545         part->remote_openclose_args = NULL;
 546 out_1:
 547         kfree(part->channels);
 548         part->channels = NULL;
 549         return ret;
 550 }
 551
 552 /*
 553  * Teardown the channel structures necessary to support XPartition Communication
 554  * between the specified remote partition and the local one.
 555  */
 556 static void
 557 xpc_teardown_ch_structures(struct xpc_partition *part)
 558 {
 559         DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
 560         DBUG_ON(atomic_read(&part->nchannels_active) != 0);
 561
 562         /*
 563          * Make this partition inaccessible to local processes by marking it
 564          * as no longer setup. Then wait before proceeding with the teardown
 565          * until all existing references cease.
 566          */
 567         DBUG_ON(part->setup_state != XPC_P_SS_SETUP);
 568         part->setup_state = XPC_P_SS_WTEARDOWN;
 569
 570         wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));
 571
 572         /* now we can begin tearing down the infrastructure */
 573
 574         xpc_teardown_ch_structures_sn(part);
 575
 576         kfree(part->remote_openclose_args_base);
 577         part->remote_openclose_args = NULL;
 578         kfree(part->channels);
 579         part->channels = NULL;
 580
 581         part->setup_state = XPC_P_SS_TORNDOWN;
 582 }
 583
 584 /*
 585  * When XPC HB determines that a partition has come up, it will create a new
 586  * kthread and that kthread will call this function to attempt to set up the
 587  * basic infrastructure used for Cross Partition Communication with the newly
 588  * upped partition.
 589  *
 590  * The kthread that was created by XPC HB and which setup the XPC
 591  * infrastructure will remain assigned to the partition becoming the channel
 592  * manager for that partition until the partition is deactivating, at which
 593  * time the kthread will teardown the XPC infrastructure and then exit.
 594  */
 595 static int
 596 xpc_activating(void *__partid)
 597 {
 598         short partid = (u64)__partid;
 599         struct xpc_partition *part = &xpc_partitions[partid];
 600         unsigned long irq_flags;
 601
 602         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
 603
 604         spin_lock_irqsave(&part->act_lock, irq_flags);
 605
 606         if (part->act_state == XPC_P_AS_DEACTIVATING) {
 607                 part->act_state = XPC_P_AS_INACTIVE;
 608                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 609                 part->remote_rp_pa = 0;
 610                 return 0;
 611         }
 612
 613         /* indicate the thread is activating */
 614         DBUG_ON(part->act_state != XPC_P_AS_ACTIVATION_REQ);
 615         part->act_state = XPC_P_AS_ACTIVATING;
 616
 617         XPC_SET_REASON(part, 0, 0);
 618         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 619
 620         dev_dbg(xpc_part, "activating partition %d\n", partid);
 621
 622         xpc_allow_hb(partid);
 623
 624         if (xpc_setup_ch_structures(part) == xpSuccess) {
 625                 (void)xpc_part_ref(part);       /* this will always succeed */
 626
 627                 if (xpc_make_first_contact(part) == xpSuccess) {
 628                         xpc_mark_partition_active(part);
 629                         xpc_channel_mgr(part);
 630                         /* won't return until partition is deactivating */
 631                 }
 632
 633                 xpc_part_deref(part);
 634                 xpc_teardown_ch_structures(part);
 635         }
 636
 637         xpc_disallow_hb(partid);
 638         xpc_mark_partition_inactive(part);
 639
 640         if (part->reason == xpReactivating) {
 641                 /* interrupting ourselves results in activating partition */
 642                 xpc_request_partition_reactivation(part);
 643         }
 644
 645         return 0;
 646 }
 647
 648 void
 649 xpc_activate_partition(struct xpc_partition *part)
 650 {
 651         short partid = XPC_PARTID(part);
 652         unsigned long irq_flags;
 653         struct task_struct *kthread;
 654
 655         spin_lock_irqsave(&part->act_lock, irq_flags);
 656
 657         DBUG_ON(part->act_state != XPC_P_AS_INACTIVE);
 658
 659         part->act_state = XPC_P_AS_ACTIVATION_REQ;
 660         XPC_SET_REASON(part, xpCloneKThread, __LINE__);
 661
 662         spin_unlock_irqrestore(&part->act_lock, irq_flags);
 663
 664         kthread = kthread_run(xpc_activating, (void *)((u64)partid), "xpc%02d",
 665                               partid);
 666         if (IS_ERR(kthread)) {
 667                 spin_lock_irqsave(&part->act_lock, irq_flags);
 668                 part->act_state = XPC_P_AS_INACTIVE;
 669                 XPC_SET_REASON(part, xpCloneKThreadFailed, __LINE__);
 670                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
 671         }
 672 }
 673
 674 void
 675 xpc_activate_kthreads(struct xpc_channel *ch, int needed)
 676 {
 677         int idle = atomic_read(&ch->kthreads_idle);
 678         int assigned = atomic_read(&ch->kthreads_assigned);
 679         int wakeup;
 680
 681         DBUG_ON(needed <= 0);
 682
 683         if (idle > 0) {
 684                 wakeup = (needed > idle) ? idle : needed;
 685                 needed -= wakeup;
 686
 687                 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
 688                         "channel=%d\n", wakeup, ch->partid, ch->number);
 689
 690                 /* only wakeup the requested number of kthreads */
 691                 wake_up_nr(&ch->idle_wq, wakeup);
 692         }
 693
 694         if (needed <= 0)
 695                 return;
 696
 697         if (needed + assigned > ch->kthreads_assigned_limit) {
 698                 needed = ch->kthreads_assigned_limit - assigned;
 699                 if (needed <= 0)
 700                         return;
 701         }
 702
 703         dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
 704                 needed, ch->partid, ch->number);
 705
 706         xpc_create_kthreads(ch, needed, 0);
 707 }
 708
 709 /*
 710  * This function is where XPC's kthreads wait for messages to deliver.
 711  */
 712 static void
 713 xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
 714 {
 715         do {
 716                 /* deliver messages to their intended recipients */
 717
 718                 while (xpc_n_of_deliverable_payloads(ch) > 0 &&
 719                        !(ch->flags & XPC_C_DISCONNECTING)) {
 720                         xpc_deliver_payload(ch);
 721                 }
 722
 723                 if (atomic_inc_return(&ch->kthreads_idle) >
 724                     ch->kthreads_idle_limit) {
 725                         /* too many idle kthreads on this channel */
 726                         atomic_dec(&ch->kthreads_idle);
 727                         break;
 728                 }
 729
 730                 dev_dbg(xpc_chan, "idle kthread calling "
 731                         "wait_event_interruptible_exclusive()\n");
 732
 733                 (void)wait_event_interruptible_exclusive(ch->idle_wq,
 734                                 (xpc_n_of_deliverable_payloads(ch) > 0 ||
 735                                  (ch->flags & XPC_C_DISCONNECTING)));
 736
 737                 atomic_dec(&ch->kthreads_idle);
 738
 739         } while (!(ch->flags & XPC_C_DISCONNECTING));
 740 }
 741
 742 static int
 743 xpc_kthread_start(void *args)
 744 {
 745         short partid = XPC_UNPACK_ARG1(args);
 746         u16 ch_number = XPC_UNPACK_ARG2(args);
 747         struct xpc_partition *part = &xpc_partitions[partid];
 748         struct xpc_channel *ch;
 749         int n_needed;
 750         unsigned long irq_flags;
 751
 752         dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
 753                 partid, ch_number);
 754
 755         ch = &part->channels[ch_number];
 756
 757         if (!(ch->flags & XPC_C_DISCONNECTING)) {
 758
 759                 /* let registerer know that connection has been established */
 760
 761                 spin_lock_irqsave(&ch->lock, irq_flags);
 762                 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
 763                         ch->flags |= XPC_C_CONNECTEDCALLOUT;
 764                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 765
 766                         xpc_connected_callout(ch);
 767
 768                         spin_lock_irqsave(&ch->lock, irq_flags);
 769                         ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
 770                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 771
 772                         /*
 773                          * It is possible that while the callout was being
 774                          * made that the remote partition sent some messages.
 775                          * If that is the case, we may need to activate
 776                          * additional kthreads to help deliver them. We only
 777                          * need one less than total #of messages to deliver.
 778                          */
 779                         n_needed = xpc_n_of_deliverable_payloads(ch) - 1;
 780                         if (n_needed > 0 && !(ch->flags & XPC_C_DISCONNECTING))
 781                                 xpc_activate_kthreads(ch, n_needed);
 782
 783                 } else {
 784                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 785                 }
 786
 787                 xpc_kthread_waitmsgs(part, ch);
 788         }
 789
 790         /* let registerer know that connection is disconnecting */
 791
 792         spin_lock_irqsave(&ch->lock, irq_flags);
 793         if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
 794             !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
 795                 ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
 796                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 797
 798                 xpc_disconnect_callout(ch, xpDisconnecting);
 799
 800                 spin_lock_irqsave(&ch->lock, irq_flags);
 801                 ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
 802         }
 803         spin_unlock_irqrestore(&ch->lock, irq_flags);
 804
 805         if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 806             atomic_dec_return(&part->nchannels_engaged) == 0) {
 807                 xpc_indicate_partition_disengaged(part);
 808         }
 809
 810         xpc_msgqueue_deref(ch);
 811
 812         dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
 813                 partid, ch_number);
 814
 815         xpc_part_deref(part);
 816         return 0;
 817 }
 818
 819 /*
 820  * For each partition that XPC has established communications with, there is
 821  * a minimum of one kernel thread assigned to perform any operation that
 822  * may potentially sleep or block (basically the callouts to the asynchronous
 823  * functions registered via xpc_connect()).
 824  *
 825  * Additional kthreads are created and destroyed by XPC as the workload
 826  * demands.
 827  *
 828  * A kthread is assigned to one of the active channels that exists for a given
 829  * partition.
 830  */
 831 void
 832 xpc_create_kthreads(struct xpc_channel *ch, int needed,
 833                     int ignore_disconnecting)
 834 {
 835         unsigned long irq_flags;
 836         u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
 837         struct xpc_partition *part = &xpc_partitions[ch->partid];
 838         struct task_struct *kthread;
 839
 840         while (needed-- > 0) {
 841
 842                 /*
 843                  * The following is done on behalf of the newly created
 844                  * kthread. That kthread is responsible for doing the
 845                  * counterpart to the following before it exits.
 846                  */
 847                 if (ignore_disconnecting) {
 848                         if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
 849                                 /* kthreads assigned had gone to zero */
 850                                 BUG_ON(!(ch->flags &
 851                                          XPC_C_DISCONNECTINGCALLOUT_MADE));
 852                                 break;
 853                         }
 854
 855                 } else if (ch->flags & XPC_C_DISCONNECTING) {
 856                         break;
 857
 858                 } else if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
 859                            atomic_inc_return(&part->nchannels_engaged) == 1) {
 860                                 xpc_indicate_partition_engaged(part);
 861                 }
 862                 (void)xpc_part_ref(part);
 863                 xpc_msgqueue_ref(ch);
 864
 865                 kthread = kthread_run(xpc_kthread_start, (void *)args,
 866                                       "xpc%02dc%d", ch->partid, ch->number);
 867                 if (IS_ERR(kthread)) {
 868                         /* the fork failed */
 869
 870                         /*
 871                          * NOTE: if (ignore_disconnecting &&
 872                          * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
 873                          * then we'll deadlock if all other kthreads assigned
 874                          * to this channel are blocked in the channel's
 875                          * registerer, because the only thing that will unblock
 876                          * them is the xpDisconnecting callout that this
 877                          * failed kthread_run() would have made.
 878                          */
 879
 880                         if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
 881                             atomic_dec_return(&part->nchannels_engaged) == 0) {
 882                                 xpc_indicate_partition_disengaged(part);
 883                         }
 884                         xpc_msgqueue_deref(ch);
 885                         xpc_part_deref(part);
 886
 887                         if (atomic_read(&ch->kthreads_assigned) <
 888                             ch->kthreads_idle_limit) {
 889                                 /*
 890                                  * Flag this as an error only if we have an
 891                                  * insufficient #of kthreads for the channel
 892                                  * to function.
 893                                  */
 894                                 spin_lock_irqsave(&ch->lock, irq_flags);
 895                                 XPC_DISCONNECT_CHANNEL(ch, xpLackOfResources,
 896                                                        &irq_flags);
 897                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 898                         }
 899                         break;
 900                 }
 901         }
 902 }
 903
 904 void
 905 xpc_disconnect_wait(int ch_number)
 906 {
 907         unsigned long irq_flags;
 908         short partid;
 909         struct xpc_partition *part;
 910         struct xpc_channel *ch;
 911         int wakeup_channel_mgr;
 912
 913         /* now wait for all callouts to the caller's function to cease */
 914         for (partid = 0; partid < xp_max_npartitions; partid++) {
 915                 part = &xpc_partitions[partid];
 916
 917                 if (!xpc_part_ref(part))
 918                         continue;
 919
 920                 ch = &part->channels[ch_number];
 921
 922                 if (!(ch->flags & XPC_C_WDISCONNECT)) {
 923                         xpc_part_deref(part);
 924                         continue;
 925                 }
 926
 927                 wait_for_completion(&ch->wdisconnect_wait);
 928
 929                 spin_lock_irqsave(&ch->lock, irq_flags);
 930                 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
 931                 wakeup_channel_mgr = 0;
 932
 933                 if (ch->delayed_chctl_flags) {
 934                         if (part->act_state != XPC_P_AS_DEACTIVATING) {
 935                                 spin_lock(&part->chctl_lock);
 936                                 part->chctl.flags[ch->number] |=
 937                                     ch->delayed_chctl_flags;
 938                                 spin_unlock(&part->chctl_lock);
 939                                 wakeup_channel_mgr = 1;
 940                         }
 941                         ch->delayed_chctl_flags = 0;
 942                 }
 943
 944                 ch->flags &= ~XPC_C_WDISCONNECT;
 945                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 946
 947                 if (wakeup_channel_mgr)
 948                         xpc_wakeup_channel_mgr(part);
 949
 950                 xpc_part_deref(part);
 951         }
 952 }
 953
 954 static int
 955 xpc_setup_partitions(void)
 956 {
 957         short partid;
 958         struct xpc_partition *part;
 959
 960         xpc_partitions = kzalloc(sizeof(struct xpc_partition) *
 961                                  xp_max_npartitions, GFP_KERNEL);
 962         if (xpc_partitions == NULL) {
 963                 dev_err(xpc_part, "can't get memory for partition structure\n");
 964                 return -ENOMEM;
 965         }
 966
 967         /*
 968          * The first few fields of each entry of xpc_partitions[] need to
 969          * be initialized now so that calls to xpc_connect() and
 970          * xpc_disconnect() can be made prior to the activation of any remote
 971          * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
 972          * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
 973          * PARTITION HAS BEEN ACTIVATED.
 974          */
 975         for (partid = 0; partid < xp_max_npartitions; partid++) {
 976                 part = &xpc_partitions[partid];
 977
 978                 DBUG_ON((u64)part != L1_CACHE_ALIGN((u64)part));
 979
 980                 part->activate_IRQ_rcvd = 0;
 981                 spin_lock_init(&part->act_lock);
 982                 part->act_state = XPC_P_AS_INACTIVE;
 983                 XPC_SET_REASON(part, 0, 0);
 984
 985                 init_timer(&part->disengage_timer);
 986                 part->disengage_timer.function =
 987                     xpc_timeout_partition_disengage;
 988                 part->disengage_timer.data = (unsigned long)part;
 989
 990                 part->setup_state = XPC_P_SS_UNSET;
 991                 init_waitqueue_head(&part->teardown_wq);
 992                 atomic_set(&part->references, 0);
 993         }
 994
 995         return xpc_setup_partitions_sn();
 996 }
 997
 998 static void
 999 xpc_teardown_partitions(void)
1000 {
1001         kfree(xpc_partitions);
1002 }
1003
1004 static void
1005 xpc_do_exit(enum xp_retval reason)
1006 {
1007         short partid;
1008         int active_part_count, printed_waiting_msg = 0;
1009         struct xpc_partition *part;
1010         unsigned long printmsg_time, disengage_timeout = 0;
1011
1012         /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
1013         DBUG_ON(xpc_exiting == 1);
1014
1015         /*
1016          * Let the heartbeat checker thread and the discovery thread
1017          * (if one is running) know that they should exit. Also wake up
1018          * the heartbeat checker thread in case it's sleeping.
1019          */
1020         xpc_exiting = 1;
1021         wake_up_interruptible(&xpc_activate_IRQ_wq);
1022
1023         /* wait for the discovery thread to exit */
1024         wait_for_completion(&xpc_discovery_exited);
1025
1026         /* wait for the heartbeat checker thread to exit */
1027         wait_for_completion(&xpc_hb_checker_exited);
1028
1029         /* sleep for a 1/3 of a second or so */
1030         (void)msleep_interruptible(300);
1031
1032         /* wait for all partitions to become inactive */
1033
1034         printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
1035         xpc_disengage_timedout = 0;
1036
1037         do {
1038                 active_part_count = 0;
1039
1040                 for (partid = 0; partid < xp_max_npartitions; partid++) {
1041                         part = &xpc_partitions[partid];
1042
1043                         if (xpc_partition_disengaged(part) &&
1044                             part->act_state == XPC_P_AS_INACTIVE) {
1045                                 continue;
1046                         }
1047
1048                         active_part_count++;
1049
1050                         XPC_DEACTIVATE_PARTITION(part, reason);
1051
1052                         if (part->disengage_timeout > disengage_timeout)
1053                                 disengage_timeout = part->disengage_timeout;
1054                 }
1055
1056                 if (xpc_any_partition_engaged()) {
1057                         if (time_is_before_jiffies(printmsg_time)) {
1058                                 dev_info(xpc_part, "waiting for remote "
1059                                          "partitions to deactivate, timeout in "
1060                                          "%ld seconds\n", (disengage_timeout -
1061                                          jiffies) / HZ);
1062                                 printmsg_time = jiffies +
1063                                     (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
1064                                 printed_waiting_msg = 1;
1065                         }
1066
1067                 } else if (active_part_count > 0) {
1068                         if (printed_waiting_msg) {
1069                                 dev_info(xpc_part, "waiting for local partition"
1070                                          " to deactivate\n");
1071                                 printed_waiting_msg = 0;
1072                         }
1073
1074                 } else {
1075                         if (!xpc_disengage_timedout) {
1076                                 dev_info(xpc_part, "all partitions have "
1077                                          "deactivated\n");
1078                         }
1079                         break;
1080                 }
1081
1082                 /* sleep for a 1/3 of a second or so */
1083                 (void)msleep_interruptible(300);
1084
1085         } while (1);
1086
1087         DBUG_ON(xpc_any_partition_engaged());
1088         DBUG_ON(xpc_any_hbs_allowed() != 0);
1089
1090         xpc_teardown_rsvd_page();
1091
1092         if (reason == xpUnloading) {
1093                 (void)unregister_die_notifier(&xpc_die_notifier);
1094                 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1095         }
1096
1097         /* clear the interface to XPC's functions */
1098         xpc_clear_interface();
1099
1100         if (xpc_sysctl)
1101                 unregister_sysctl_table(xpc_sysctl);
1102
1103         xpc_teardown_partitions();
1104
1105         if (is_shub())
1106                 xpc_exit_sn2();
1107         else if (is_uv())
1108                 xpc_exit_uv();
1109 }
1110
1111 /*
1112  * This function is called when the system is being rebooted.
1113  */
1114 static int
1115 xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1116 {
1117         enum xp_retval reason;
1118
1119         switch (event) {
1120         case SYS_RESTART:
1121                 reason = xpSystemReboot;
1122                 break;
1123         case SYS_HALT:
1124                 reason = xpSystemHalt;
1125                 break;
1126         case SYS_POWER_OFF:
1127                 reason = xpSystemPoweroff;
1128                 break;
1129         default:
1130                 reason = xpSystemGoingDown;
1131         }
1132
1133         xpc_do_exit(reason);
1134         return NOTIFY_DONE;
1135 }
1136
1137 /*
1138  * Notify other partitions to deactivate from us by first disengaging from all
1139  * references to our memory.
1140  */
1141 static void
1142 xpc_die_deactivate(void)
1143 {
1144         struct xpc_partition *part;
1145         short partid;
1146         int any_engaged;
1147         long keep_waiting;
1148         long wait_to_print;
1149
1150         /* keep xpc_hb_checker thread from doing anything (just in case) */
1151         xpc_exiting = 1;
1152
1153         xpc_disallow_all_hbs(); /*indicate we're deactivated */
1154
1155         for (partid = 0; partid < xp_max_npartitions; partid++) {
1156                 part = &xpc_partitions[partid];
1157
1158                 if (xpc_partition_engaged(partid) ||
1159                     part->act_state != XPC_P_AS_INACTIVE) {
1160                         xpc_request_partition_deactivation(part);
1161                         xpc_indicate_partition_disengaged(part);
1162                 }
1163         }
1164
1165         /*
1166          * Though we requested that all other partitions deactivate from us,
1167          * we only wait until they've all disengaged or we've reached the
1168          * defined timelimit.
1169          *
1170          * Given that one iteration through the following while-loop takes
1171          * approximately 200 microseconds, calculate the #of loops to take
1172          * before bailing and the #of loops before printing a waiting message.
1173          */
1174         keep_waiting = xpc_disengage_timelimit * 1000 * 5;
1175         wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5;
1176
1177         while (1) {
1178                 any_engaged = xpc_any_partition_engaged();
1179                 if (!any_engaged) {
1180                         dev_info(xpc_part, "all partitions have deactivated\n");
1181                         break;
1182                 }
1183
1184                 if (!keep_waiting--) {
1185                         for (partid = 0; partid < xp_max_npartitions;
1186                              partid++) {
1187                                 if (xpc_partition_engaged(partid)) {
1188                                         dev_info(xpc_part, "deactivate from "
1189                                                  "remote partition %d timed "
1190                                                  "out\n", partid);
1191                                 }
1192                         }
1193                         break;
1194                 }
1195
1196                 if (!wait_to_print--) {
1197                         dev_info(xpc_part, "waiting for remote partitions to "
1198                                  "deactivate, timeout in %ld seconds\n",
1199                                  keep_waiting / (1000 * 5));
1200                         wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL *
1201                             1000 * 5;
1202                 }
1203
1204                 udelay(200);
1205         }
1206 }
1207
1208 /*
1209  * This function is called when the system is being restarted or halted due
1210  * to some sort of system failure. If this is the case we need to notify the
1211  * other partitions to disengage from all references to our memory.
1212  * This function can also be called when our heartbeater could be offlined
1213  * for a time. In this case we need to notify other partitions to not worry
1214  * about the lack of a heartbeat.
1215  */
1216 static int
1217 xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1218 {
1219 #ifdef CONFIG_IA64              /* !!! temporary kludge */
1220         switch (event) {
1221         case DIE_MACHINE_RESTART:
1222         case DIE_MACHINE_HALT:
1223                 xpc_die_deactivate();
1224                 break;
1225
1226         case DIE_KDEBUG_ENTER:
1227                 /* Should lack of heartbeat be ignored by other partitions? */
1228                 if (!xpc_kdebug_ignore)
1229                         break;
1230
1231                 /* fall through */
1232         case DIE_MCA_MONARCH_ENTER:
1233         case DIE_INIT_MONARCH_ENTER:
1234                 xpc_offline_heartbeat();
1235                 break;
1236
1237         case DIE_KDEBUG_LEAVE:
1238                 /* Is lack of heartbeat being ignored by other partitions? */
1239                 if (!xpc_kdebug_ignore)
1240                         break;
1241
1242                 /* fall through */
1243         case DIE_MCA_MONARCH_LEAVE:
1244         case DIE_INIT_MONARCH_LEAVE:
1245                 xpc_online_heartbeat();
1246                 break;
1247         }
1248 #else
1249         xpc_die_deactivate();
1250 #endif
1251
1252         return NOTIFY_DONE;
1253 }
1254
1255 int __init
1256 xpc_init(void)
1257 {
1258         int ret;
1259         struct task_struct *kthread;
1260
1261         dev_set_name(xpc_part, "part");
1262         dev_set_name(xpc_chan, "chan");
1263
1264         if (is_shub()) {
1265                 /*
1266                  * The ia64-sn2 architecture supports at most 64 partitions.
1267                  * And the inability to unregister remote amos restricts us
1268                  * further to only support exactly 64 partitions on this
1269                  * architecture, no less.
1270                  */
1271                 if (xp_max_npartitions != 64) {
1272                         dev_err(xpc_part, "max #of partitions not set to 64\n");
1273                         ret = -EINVAL;
1274                 } else {
1275                         ret = xpc_init_sn2();
1276                 }
1277
1278         } else if (is_uv()) {
1279                 ret = xpc_init_uv();
1280
1281         } else {
1282                 ret = -ENODEV;
1283         }
1284
1285         if (ret != 0)
1286                 return ret;
1287
1288         ret = xpc_setup_partitions();
1289         if (ret != 0) {
1290                 dev_err(xpc_part, "can't get memory for partition structure\n");
1291                 goto out_1;
1292         }
1293
1294         xpc_sysctl = register_sysctl_table(xpc_sys_dir);
1295
1296         /*
1297          * Fill the partition reserved page with the information needed by
1298          * other partitions to discover we are alive and establish initial
1299          * communications.
1300          */
1301         ret = xpc_setup_rsvd_page();
1302         if (ret != 0) {
1303                 dev_err(xpc_part, "can't setup our reserved page\n");
1304                 goto out_2;
1305         }
1306
1307         /* add ourselves to the reboot_notifier_list */
1308         ret = register_reboot_notifier(&xpc_reboot_notifier);
1309         if (ret != 0)
1310                 dev_warn(xpc_part, "can't register reboot notifier\n");
1311
1312         /* add ourselves to the die_notifier list */
1313         ret = register_die_notifier(&xpc_die_notifier);
1314         if (ret != 0)
1315                 dev_warn(xpc_part, "can't register die notifier\n");
1316
1317         /*
1318          * The real work-horse behind xpc.  This processes incoming
1319          * interrupts and monitors remote heartbeats.
1320          */
1321         kthread = kthread_run(xpc_hb_checker, NULL, XPC_HB_CHECK_THREAD_NAME);
1322         if (IS_ERR(kthread)) {
1323                 dev_err(xpc_part, "failed while forking hb check thread\n");
1324                 ret = -EBUSY;
1325                 goto out_3;
1326         }
1327
1328         /*
1329          * Startup a thread that will attempt to discover other partitions to
1330          * activate based on info provided by SAL. This new thread is short
1331          * lived and will exit once discovery is complete.
1332          */
1333         kthread = kthread_run(xpc_initiate_discovery, NULL,
1334                               XPC_DISCOVERY_THREAD_NAME);
1335         if (IS_ERR(kthread)) {
1336                 dev_err(xpc_part, "failed while forking discovery thread\n");
1337
1338                 /* mark this new thread as a non-starter */
1339                 complete(&xpc_discovery_exited);
1340
1341                 xpc_do_exit(xpUnloading);
1342                 return -EBUSY;
1343         }
1344
1345         /* set the interface to point at XPC's functions */
1346         xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1347                           xpc_initiate_send, xpc_initiate_send_notify,
1348                           xpc_initiate_received, xpc_initiate_partid_to_nasids);
1349
1350         return 0;
1351
1352         /* initialization was not successful */
1353 out_3:
1354         xpc_teardown_rsvd_page();
1355
1356         (void)unregister_die_notifier(&xpc_die_notifier);
1357         (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1358 out_2:
1359         if (xpc_sysctl)
1360                 unregister_sysctl_table(xpc_sysctl);
1361
1362         xpc_teardown_partitions();
1363 out_1:
1364         if (is_shub())
1365                 xpc_exit_sn2();
1366         else if (is_uv())
1367                 xpc_exit_uv();
1368         return ret;
1369 }
1370
1371 module_init(xpc_init);
1372
1373 void __exit
1374 xpc_exit(void)
1375 {
1376         xpc_do_exit(xpUnloading);
1377 }
1378
1379 module_exit(xpc_exit);
1380
1381 MODULE_AUTHOR("Silicon Graphics, Inc.");
1382 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1383 MODULE_LICENSE("GPL");
1384
1385 module_param(xpc_hb_interval, int, 0);
1386 MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1387                  "heartbeat increments.");
1388
1389 module_param(xpc_hb_check_interval, int, 0);
1390 MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1391                  "heartbeat checks.");
1392
1393 module_param(xpc_disengage_timelimit, int, 0);
1394 MODULE_PARM_DESC(xpc_disengage_timelimit, "Number of seconds to wait "
1395                  "for disengage to complete.");
1396
1397 module_param(xpc_kdebug_ignore, int, 0);
1398 MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1399                  "other partitions when dropping into kdebug.");