Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6
[linux-2.6] / arch / ia64 / sn / kernel / xpc_main.c
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (c) 2004-2006 Silicon Graphics, Inc.  All Rights Reserved.
7  */
8
9
10 /*
11  * Cross Partition Communication (XPC) support - standard version.
12  *
13  *      XPC provides a message passing capability that crosses partition
14  *      boundaries. This module is made up of two parts:
15  *
16  *          partition   This part detects the presence/absence of other
17  *                      partitions. It provides a heartbeat and monitors
18  *                      the heartbeats of other partitions.
19  *
20  *          channel     This part manages the channels and sends/receives
21  *                      messages across them to/from other partitions.
22  *
23  *      There are a couple of additional functions residing in XP, which
24  *      provide an interface to XPC for its users.
25  *
26  *
27  *      Caveats:
28  *
29  *        . We currently have no way to determine which nasid an IPI came
30  *          from. Thus, xpc_IPI_send() does a remote AMO write followed by
31  *          an IPI. The AMO indicates where data is to be pulled from, so
32  *          after the IPI arrives, the remote partition checks the AMO word.
33  *          The IPI can actually arrive before the AMO however, so other code
34  *          must periodically check for this case. Also, remote AMO operations
35  *          do not reliably time out. Thus we do a remote PIO read solely to
36  *          know whether the remote partition is down and whether we should
37  *          stop sending IPIs to it. This remote PIO read operation is set up
38  *          in a special nofault region so SAL knows to ignore (and cleanup)
39  *          any errors due to the remote AMO write, PIO read, and/or PIO
40  *          write operations.
41  *
42  *          If/when new hardware solves this IPI problem, we should abandon
43  *          the current approach.
44  *
45  */
46
47
48 #include <linux/kernel.h>
49 #include <linux/module.h>
50 #include <linux/init.h>
51 #include <linux/sched.h>
52 #include <linux/syscalls.h>
53 #include <linux/cache.h>
54 #include <linux/interrupt.h>
55 #include <linux/slab.h>
56 #include <linux/delay.h>
57 #include <linux/reboot.h>
58 #include <asm/sn/intr.h>
59 #include <asm/sn/sn_sal.h>
60 #include <asm/kdebug.h>
61 #include <asm/uaccess.h>
62 #include <asm/sn/xpc.h>
63
64
65 /* define two XPC debug device structures to be used with dev_dbg() et al */
66
67 struct device_driver xpc_dbg_name = {
68         .name = "xpc"
69 };
70
71 struct device xpc_part_dbg_subname = {
72         .bus_id = {0},          /* set to "part" at xpc_init() time */
73         .driver = &xpc_dbg_name
74 };
75
76 struct device xpc_chan_dbg_subname = {
77         .bus_id = {0},          /* set to "chan" at xpc_init() time */
78         .driver = &xpc_dbg_name
79 };
80
81 struct device *xpc_part = &xpc_part_dbg_subname;
82 struct device *xpc_chan = &xpc_chan_dbg_subname;
83
84
85 static int xpc_kdebug_ignore;
86
87
88 /* systune related variables for /proc/sys directories */
89
90 static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
91 static int xpc_hb_min_interval = 1;
92 static int xpc_hb_max_interval = 10;
93
94 static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
95 static int xpc_hb_check_min_interval = 10;
96 static int xpc_hb_check_max_interval = 120;
97
98 int xpc_disengage_request_timelimit = XPC_DISENGAGE_REQUEST_DEFAULT_TIMELIMIT;
99 static int xpc_disengage_request_min_timelimit = 0;
100 static int xpc_disengage_request_max_timelimit = 120;
101
102 static ctl_table xpc_sys_xpc_hb_dir[] = {
103         {
104                 1,
105                 "hb_interval",
106                 &xpc_hb_interval,
107                 sizeof(int),
108                 0644,
109                 NULL,
110                 &proc_dointvec_minmax,
111                 &sysctl_intvec,
112                 NULL,
113                 &xpc_hb_min_interval,
114                 &xpc_hb_max_interval
115         },
116         {
117                 2,
118                 "hb_check_interval",
119                 &xpc_hb_check_interval,
120                 sizeof(int),
121                 0644,
122                 NULL,
123                 &proc_dointvec_minmax,
124                 &sysctl_intvec,
125                 NULL,
126                 &xpc_hb_check_min_interval,
127                 &xpc_hb_check_max_interval
128         },
129         {0}
130 };
131 static ctl_table xpc_sys_xpc_dir[] = {
132         {
133                 1,
134                 "hb",
135                 NULL,
136                 0,
137                 0555,
138                 xpc_sys_xpc_hb_dir
139         },
140         {
141                 2,
142                 "disengage_request_timelimit",
143                 &xpc_disengage_request_timelimit,
144                 sizeof(int),
145                 0644,
146                 NULL,
147                 &proc_dointvec_minmax,
148                 &sysctl_intvec,
149                 NULL,
150                 &xpc_disengage_request_min_timelimit,
151                 &xpc_disengage_request_max_timelimit
152         },
153         {0}
154 };
155 static ctl_table xpc_sys_dir[] = {
156         {
157                 1,
158                 "xpc",
159                 NULL,
160                 0,
161                 0555,
162                 xpc_sys_xpc_dir
163         },
164         {0}
165 };
166 static struct ctl_table_header *xpc_sysctl;
167
168 /* non-zero if any remote partition disengage request was timed out */
169 int xpc_disengage_request_timedout;
170
171 /* #of IRQs received */
172 static atomic_t xpc_act_IRQ_rcvd;
173
174 /* IRQ handler notifies this wait queue on receipt of an IRQ */
175 static DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq);
176
177 static unsigned long xpc_hb_check_timeout;
178
179 /* notification that the xpc_hb_checker thread has exited */
180 static DECLARE_MUTEX_LOCKED(xpc_hb_checker_exited);
181
182 /* notification that the xpc_discovery thread has exited */
183 static DECLARE_MUTEX_LOCKED(xpc_discovery_exited);
184
185
186 static struct timer_list xpc_hb_timer;
187
188
189 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
190
191
192 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
193 static struct notifier_block xpc_reboot_notifier = {
194         .notifier_call = xpc_system_reboot,
195 };
196
197 static int xpc_system_die(struct notifier_block *, unsigned long, void *);
198 static struct notifier_block xpc_die_notifier = {
199         .notifier_call = xpc_system_die,
200 };
201
202
203 /*
204  * Timer function to enforce the timelimit on the partition disengage request.
205  */
206 static void
207 xpc_timeout_partition_disengage_request(unsigned long data)
208 {
209         struct xpc_partition *part = (struct xpc_partition *) data;
210
211
212         DBUG_ON(jiffies < part->disengage_request_timeout);
213
214         (void) xpc_partition_disengaged(part);
215
216         DBUG_ON(part->disengage_request_timeout != 0);
217         DBUG_ON(xpc_partition_engaged(1UL << XPC_PARTID(part)) != 0);
218 }
219
220
221 /*
222  * Notify the heartbeat check thread that an IRQ has been received.
223  */
224 static irqreturn_t
225 xpc_act_IRQ_handler(int irq, void *dev_id, struct pt_regs *regs)
226 {
227         atomic_inc(&xpc_act_IRQ_rcvd);
228         wake_up_interruptible(&xpc_act_IRQ_wq);
229         return IRQ_HANDLED;
230 }
231
232
233 /*
234  * Timer to produce the heartbeat.  The timer structures function is
235  * already set when this is initially called.  A tunable is used to
236  * specify when the next timeout should occur.
237  */
238 static void
239 xpc_hb_beater(unsigned long dummy)
240 {
241         xpc_vars->heartbeat++;
242
243         if (jiffies >= xpc_hb_check_timeout) {
244                 wake_up_interruptible(&xpc_act_IRQ_wq);
245         }
246
247         xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
248         add_timer(&xpc_hb_timer);
249 }
250
251
252 /*
253  * This thread is responsible for nearly all of the partition
254  * activation/deactivation.
255  */
256 static int
257 xpc_hb_checker(void *ignore)
258 {
259         int last_IRQ_count = 0;
260         int new_IRQ_count;
261         int force_IRQ=0;
262
263
264         /* this thread was marked active by xpc_hb_init() */
265
266         daemonize(XPC_HB_CHECK_THREAD_NAME);
267
268         set_cpus_allowed(current, cpumask_of_cpu(XPC_HB_CHECK_CPU));
269
270         xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
271
272         while (!(volatile int) xpc_exiting) {
273
274                 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
275                         "been received\n",
276                         (int) (xpc_hb_check_timeout - jiffies),
277                         atomic_read(&xpc_act_IRQ_rcvd) - last_IRQ_count);
278
279
280                 /* checking of remote heartbeats is skewed by IRQ handling */
281                 if (jiffies >= xpc_hb_check_timeout) {
282                         dev_dbg(xpc_part, "checking remote heartbeats\n");
283                         xpc_check_remote_hb();
284
285                         /*
286                          * We need to periodically recheck to ensure no
287                          * IPI/AMO pairs have been missed.  That check
288                          * must always reset xpc_hb_check_timeout.
289                          */
290                         force_IRQ = 1;
291                 }
292
293
294                 /* check for outstanding IRQs */
295                 new_IRQ_count = atomic_read(&xpc_act_IRQ_rcvd);
296                 if (last_IRQ_count < new_IRQ_count || force_IRQ != 0) {
297                         force_IRQ = 0;
298
299                         dev_dbg(xpc_part, "found an IRQ to process; will be "
300                                 "resetting xpc_hb_check_timeout\n");
301
302                         last_IRQ_count += xpc_identify_act_IRQ_sender();
303                         if (last_IRQ_count < new_IRQ_count) {
304                                 /* retry once to help avoid missing AMO */
305                                 (void) xpc_identify_act_IRQ_sender();
306                         }
307                         last_IRQ_count = new_IRQ_count;
308
309                         xpc_hb_check_timeout = jiffies +
310                                            (xpc_hb_check_interval * HZ);
311                 }
312
313                 /* wait for IRQ or timeout */
314                 (void) wait_event_interruptible(xpc_act_IRQ_wq,
315                             (last_IRQ_count < atomic_read(&xpc_act_IRQ_rcvd) ||
316                                         jiffies >= xpc_hb_check_timeout ||
317                                                 (volatile int) xpc_exiting));
318         }
319
320         dev_dbg(xpc_part, "heartbeat checker is exiting\n");
321
322
323         /* mark this thread as having exited */
324         up(&xpc_hb_checker_exited);
325         return 0;
326 }
327
328
329 /*
330  * This thread will attempt to discover other partitions to activate
331  * based on info provided by SAL. This new thread is short lived and
332  * will exit once discovery is complete.
333  */
334 static int
335 xpc_initiate_discovery(void *ignore)
336 {
337         daemonize(XPC_DISCOVERY_THREAD_NAME);
338
339         xpc_discovery();
340
341         dev_dbg(xpc_part, "discovery thread is exiting\n");
342
343         /* mark this thread as having exited */
344         up(&xpc_discovery_exited);
345         return 0;
346 }
347
348
349 /*
350  * Establish first contact with the remote partititon. This involves pulling
351  * the XPC per partition variables from the remote partition and waiting for
352  * the remote partition to pull ours.
353  */
354 static enum xpc_retval
355 xpc_make_first_contact(struct xpc_partition *part)
356 {
357         enum xpc_retval ret;
358
359
360         while ((ret = xpc_pull_remote_vars_part(part)) != xpcSuccess) {
361                 if (ret != xpcRetry) {
362                         XPC_DEACTIVATE_PARTITION(part, ret);
363                         return ret;
364                 }
365
366                 dev_dbg(xpc_chan, "waiting to make first contact with "
367                         "partition %d\n", XPC_PARTID(part));
368
369                 /* wait a 1/4 of a second or so */
370                 (void) msleep_interruptible(250);
371
372                 if (part->act_state == XPC_P_DEACTIVATING) {
373                         return part->reason;
374                 }
375         }
376
377         return xpc_mark_partition_active(part);
378 }
379
380
381 /*
382  * The first kthread assigned to a newly activated partition is the one
383  * created by XPC HB with which it calls xpc_partition_up(). XPC hangs on to
384  * that kthread until the partition is brought down, at which time that kthread
385  * returns back to XPC HB. (The return of that kthread will signify to XPC HB
386  * that XPC has dismantled all communication infrastructure for the associated
387  * partition.) This kthread becomes the channel manager for that partition.
388  *
389  * Each active partition has a channel manager, who, besides connecting and
390  * disconnecting channels, will ensure that each of the partition's connected
391  * channels has the required number of assigned kthreads to get the work done.
392  */
393 static void
394 xpc_channel_mgr(struct xpc_partition *part)
395 {
396         while (part->act_state != XPC_P_DEACTIVATING ||
397                         atomic_read(&part->nchannels_active) > 0 ||
398                                         !xpc_partition_disengaged(part)) {
399
400                 xpc_process_channel_activity(part);
401
402
403                 /*
404                  * Wait until we've been requested to activate kthreads or
405                  * all of the channel's message queues have been torn down or
406                  * a signal is pending.
407                  *
408                  * The channel_mgr_requests is set to 1 after being awakened,
409                  * This is done to prevent the channel mgr from making one pass
410                  * through the loop for each request, since he will
411                  * be servicing all the requests in one pass. The reason it's
412                  * set to 1 instead of 0 is so that other kthreads will know
413                  * that the channel mgr is running and won't bother trying to
414                  * wake him up.
415                  */
416                 atomic_dec(&part->channel_mgr_requests);
417                 (void) wait_event_interruptible(part->channel_mgr_wq,
418                                 (atomic_read(&part->channel_mgr_requests) > 0 ||
419                                 (volatile u64) part->local_IPI_amo != 0 ||
420                                 ((volatile u8) part->act_state ==
421                                                         XPC_P_DEACTIVATING &&
422                                 atomic_read(&part->nchannels_active) == 0 &&
423                                 xpc_partition_disengaged(part))));
424                 atomic_set(&part->channel_mgr_requests, 1);
425
426                 // >>> Does it need to wakeup periodically as well? In case we
427                 // >>> miscalculated the #of kthreads to wakeup or create?
428         }
429 }
430
431
432 /*
433  * When XPC HB determines that a partition has come up, it will create a new
434  * kthread and that kthread will call this function to attempt to set up the
435  * basic infrastructure used for Cross Partition Communication with the newly
436  * upped partition.
437  *
438  * The kthread that was created by XPC HB and which setup the XPC
439  * infrastructure will remain assigned to the partition until the partition
440  * goes down. At which time the kthread will teardown the XPC infrastructure
441  * and then exit.
442  *
443  * XPC HB will put the remote partition's XPC per partition specific variables
444  * physical address into xpc_partitions[partid].remote_vars_part_pa prior to
445  * calling xpc_partition_up().
446  */
447 static void
448 xpc_partition_up(struct xpc_partition *part)
449 {
450         DBUG_ON(part->channels != NULL);
451
452         dev_dbg(xpc_chan, "activating partition %d\n", XPC_PARTID(part));
453
454         if (xpc_setup_infrastructure(part) != xpcSuccess) {
455                 return;
456         }
457
458         /*
459          * The kthread that XPC HB called us with will become the
460          * channel manager for this partition. It will not return
461          * back to XPC HB until the partition's XPC infrastructure
462          * has been dismantled.
463          */
464
465         (void) xpc_part_ref(part);      /* this will always succeed */
466
467         if (xpc_make_first_contact(part) == xpcSuccess) {
468                 xpc_channel_mgr(part);
469         }
470
471         xpc_part_deref(part);
472
473         xpc_teardown_infrastructure(part);
474 }
475
476
477 static int
478 xpc_activating(void *__partid)
479 {
480         partid_t partid = (u64) __partid;
481         struct xpc_partition *part = &xpc_partitions[partid];
482         unsigned long irq_flags;
483         struct sched_param param = { sched_priority: MAX_RT_PRIO - 1 };
484         int ret;
485
486
487         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
488
489         spin_lock_irqsave(&part->act_lock, irq_flags);
490
491         if (part->act_state == XPC_P_DEACTIVATING) {
492                 part->act_state = XPC_P_INACTIVE;
493                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
494                 part->remote_rp_pa = 0;
495                 return 0;
496         }
497
498         /* indicate the thread is activating */
499         DBUG_ON(part->act_state != XPC_P_ACTIVATION_REQ);
500         part->act_state = XPC_P_ACTIVATING;
501
502         XPC_SET_REASON(part, 0, 0);
503         spin_unlock_irqrestore(&part->act_lock, irq_flags);
504
505         dev_dbg(xpc_part, "bringing partition %d up\n", partid);
506
507         daemonize("xpc%02d", partid);
508
509         /*
510          * This thread needs to run at a realtime priority to prevent a
511          * significant performance degradation.
512          */
513         ret = sched_setscheduler(current, SCHED_FIFO, &param);
514         if (ret != 0) {
515                 dev_warn(xpc_part, "unable to set pid %d to a realtime "
516                         "priority, ret=%d\n", current->pid, ret);
517         }
518
519         /* allow this thread and its children to run on any CPU */
520         set_cpus_allowed(current, CPU_MASK_ALL);
521
522         /*
523          * Register the remote partition's AMOs with SAL so it can handle
524          * and cleanup errors within that address range should the remote
525          * partition go down. We don't unregister this range because it is
526          * difficult to tell when outstanding writes to the remote partition
527          * are finished and thus when it is safe to unregister. This should
528          * not result in wasted space in the SAL xp_addr_region table because
529          * we should get the same page for remote_amos_page_pa after module
530          * reloads and system reboots.
531          */
532         if (sn_register_xp_addr_region(part->remote_amos_page_pa,
533                                                         PAGE_SIZE, 1) < 0) {
534                 dev_warn(xpc_part, "xpc_partition_up(%d) failed to register "
535                         "xp_addr region\n", partid);
536
537                 spin_lock_irqsave(&part->act_lock, irq_flags);
538                 part->act_state = XPC_P_INACTIVE;
539                 XPC_SET_REASON(part, xpcPhysAddrRegFailed, __LINE__);
540                 spin_unlock_irqrestore(&part->act_lock, irq_flags);
541                 part->remote_rp_pa = 0;
542                 return 0;
543         }
544
545         xpc_allow_hb(partid, xpc_vars);
546         xpc_IPI_send_activated(part);
547
548
549         /*
550          * xpc_partition_up() holds this thread and marks this partition as
551          * XPC_P_ACTIVE by calling xpc_hb_mark_active().
552          */
553         (void) xpc_partition_up(part);
554
555         xpc_disallow_hb(partid, xpc_vars);
556         xpc_mark_partition_inactive(part);
557
558         if (part->reason == xpcReactivating) {
559                 /* interrupting ourselves results in activating partition */
560                 xpc_IPI_send_reactivate(part);
561         }
562
563         return 0;
564 }
565
566
567 void
568 xpc_activate_partition(struct xpc_partition *part)
569 {
570         partid_t partid = XPC_PARTID(part);
571         unsigned long irq_flags;
572         pid_t pid;
573
574
575         spin_lock_irqsave(&part->act_lock, irq_flags);
576
577         pid = kernel_thread(xpc_activating, (void *) ((u64) partid), 0);
578
579         DBUG_ON(part->act_state != XPC_P_INACTIVE);
580
581         if (pid > 0) {
582                 part->act_state = XPC_P_ACTIVATION_REQ;
583                 XPC_SET_REASON(part, xpcCloneKThread, __LINE__);
584         } else {
585                 XPC_SET_REASON(part, xpcCloneKThreadFailed, __LINE__);
586         }
587
588         spin_unlock_irqrestore(&part->act_lock, irq_flags);
589 }
590
591
592 /*
593  * Handle the receipt of a SGI_XPC_NOTIFY IRQ by seeing whether the specified
594  * partition actually sent it. Since SGI_XPC_NOTIFY IRQs may be shared by more
595  * than one partition, we use an AMO_t structure per partition to indicate
596  * whether a partition has sent an IPI or not.  >>> If it has, then wake up the
597  * associated kthread to handle it.
598  *
599  * All SGI_XPC_NOTIFY IRQs received by XPC are the result of IPIs sent by XPC
600  * running on other partitions.
601  *
602  * Noteworthy Arguments:
603  *
604  *      irq - Interrupt ReQuest number. NOT USED.
605  *
606  *      dev_id - partid of IPI's potential sender.
607  *
608  *      regs - processor's context before the processor entered
609  *             interrupt code. NOT USED.
610  */
611 irqreturn_t
612 xpc_notify_IRQ_handler(int irq, void *dev_id, struct pt_regs *regs)
613 {
614         partid_t partid = (partid_t) (u64) dev_id;
615         struct xpc_partition *part = &xpc_partitions[partid];
616
617
618         DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
619
620         if (xpc_part_ref(part)) {
621                 xpc_check_for_channel_activity(part);
622
623                 xpc_part_deref(part);
624         }
625         return IRQ_HANDLED;
626 }
627
628
629 /*
630  * Check to see if xpc_notify_IRQ_handler() dropped any IPIs on the floor
631  * because the write to their associated IPI amo completed after the IRQ/IPI
632  * was received.
633  */
634 void
635 xpc_dropped_IPI_check(struct xpc_partition *part)
636 {
637         if (xpc_part_ref(part)) {
638                 xpc_check_for_channel_activity(part);
639
640                 part->dropped_IPI_timer.expires = jiffies +
641                                                         XPC_P_DROPPED_IPI_WAIT;
642                 add_timer(&part->dropped_IPI_timer);
643                 xpc_part_deref(part);
644         }
645 }
646
647
648 void
649 xpc_activate_kthreads(struct xpc_channel *ch, int needed)
650 {
651         int idle = atomic_read(&ch->kthreads_idle);
652         int assigned = atomic_read(&ch->kthreads_assigned);
653         int wakeup;
654
655
656         DBUG_ON(needed <= 0);
657
658         if (idle > 0) {
659                 wakeup = (needed > idle) ? idle : needed;
660                 needed -= wakeup;
661
662                 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
663                         "channel=%d\n", wakeup, ch->partid, ch->number);
664
665                 /* only wakeup the requested number of kthreads */
666                 wake_up_nr(&ch->idle_wq, wakeup);
667         }
668
669         if (needed <= 0) {
670                 return;
671         }
672
673         if (needed + assigned > ch->kthreads_assigned_limit) {
674                 needed = ch->kthreads_assigned_limit - assigned;
675                 // >>>should never be less than 0
676                 if (needed <= 0) {
677                         return;
678                 }
679         }
680
681         dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
682                 needed, ch->partid, ch->number);
683
684         xpc_create_kthreads(ch, needed);
685 }
686
687
688 /*
689  * This function is where XPC's kthreads wait for messages to deliver.
690  */
691 static void
692 xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
693 {
694         do {
695                 /* deliver messages to their intended recipients */
696
697                 while ((volatile s64) ch->w_local_GP.get <
698                                 (volatile s64) ch->w_remote_GP.put &&
699                                         !((volatile u32) ch->flags &
700                                                 XPC_C_DISCONNECTING)) {
701                         xpc_deliver_msg(ch);
702                 }
703
704                 if (atomic_inc_return(&ch->kthreads_idle) >
705                                                 ch->kthreads_idle_limit) {
706                         /* too many idle kthreads on this channel */
707                         atomic_dec(&ch->kthreads_idle);
708                         break;
709                 }
710
711                 dev_dbg(xpc_chan, "idle kthread calling "
712                         "wait_event_interruptible_exclusive()\n");
713
714                 (void) wait_event_interruptible_exclusive(ch->idle_wq,
715                                 ((volatile s64) ch->w_local_GP.get <
716                                         (volatile s64) ch->w_remote_GP.put ||
717                                 ((volatile u32) ch->flags &
718                                                 XPC_C_DISCONNECTING)));
719
720                 atomic_dec(&ch->kthreads_idle);
721
722         } while (!((volatile u32) ch->flags & XPC_C_DISCONNECTING));
723 }
724
725
726 static int
727 xpc_daemonize_kthread(void *args)
728 {
729         partid_t partid = XPC_UNPACK_ARG1(args);
730         u16 ch_number = XPC_UNPACK_ARG2(args);
731         struct xpc_partition *part = &xpc_partitions[partid];
732         struct xpc_channel *ch;
733         int n_needed;
734         unsigned long irq_flags;
735
736
737         daemonize("xpc%02dc%d", partid, ch_number);
738
739         dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
740                 partid, ch_number);
741
742         ch = &part->channels[ch_number];
743
744         if (!(ch->flags & XPC_C_DISCONNECTING)) {
745
746                 /* let registerer know that connection has been established */
747
748                 spin_lock_irqsave(&ch->lock, irq_flags);
749                 if (!(ch->flags & XPC_C_CONNECTCALLOUT)) {
750                         ch->flags |= XPC_C_CONNECTCALLOUT;
751                         spin_unlock_irqrestore(&ch->lock, irq_flags);
752
753                         xpc_connected_callout(ch);
754
755                         /*
756                          * It is possible that while the callout was being
757                          * made that the remote partition sent some messages.
758                          * If that is the case, we may need to activate
759                          * additional kthreads to help deliver them. We only
760                          * need one less than total #of messages to deliver.
761                          */
762                         n_needed = ch->w_remote_GP.put - ch->w_local_GP.get - 1;
763                         if (n_needed > 0 &&
764                                         !(ch->flags & XPC_C_DISCONNECTING)) {
765                                 xpc_activate_kthreads(ch, n_needed);
766                         }
767                 } else {
768                         spin_unlock_irqrestore(&ch->lock, irq_flags);
769                 }
770
771                 xpc_kthread_waitmsgs(part, ch);
772         }
773
774         if (atomic_dec_return(&ch->kthreads_assigned) == 0) {
775                 spin_lock_irqsave(&ch->lock, irq_flags);
776                 if ((ch->flags & XPC_C_CONNECTCALLOUT) &&
777                                 !(ch->flags & XPC_C_DISCONNECTCALLOUT)) {
778                         ch->flags |= XPC_C_DISCONNECTCALLOUT;
779                         spin_unlock_irqrestore(&ch->lock, irq_flags);
780
781                         xpc_disconnect_callout(ch, xpcDisconnecting);
782                 } else {
783                         spin_unlock_irqrestore(&ch->lock, irq_flags);
784                 }
785                 if (atomic_dec_return(&part->nchannels_engaged) == 0) {
786                         xpc_mark_partition_disengaged(part);
787                         xpc_IPI_send_disengage(part);
788                 }
789         }
790
791
792         xpc_msgqueue_deref(ch);
793
794         dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
795                 partid, ch_number);
796
797         xpc_part_deref(part);
798         return 0;
799 }
800
801
802 /*
803  * For each partition that XPC has established communications with, there is
804  * a minimum of one kernel thread assigned to perform any operation that
805  * may potentially sleep or block (basically the callouts to the asynchronous
806  * functions registered via xpc_connect()).
807  *
808  * Additional kthreads are created and destroyed by XPC as the workload
809  * demands.
810  *
811  * A kthread is assigned to one of the active channels that exists for a given
812  * partition.
813  */
814 void
815 xpc_create_kthreads(struct xpc_channel *ch, int needed)
816 {
817         unsigned long irq_flags;
818         pid_t pid;
819         u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
820         struct xpc_partition *part = &xpc_partitions[ch->partid];
821
822
823         while (needed-- > 0) {
824
825                 /*
826                  * The following is done on behalf of the newly created
827                  * kthread. That kthread is responsible for doing the
828                  * counterpart to the following before it exits.
829                  */
830                 (void) xpc_part_ref(part);
831                 xpc_msgqueue_ref(ch);
832                 if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
833                     atomic_inc_return(&part->nchannels_engaged) == 1) {
834                         xpc_mark_partition_engaged(part);
835                 }
836
837                 pid = kernel_thread(xpc_daemonize_kthread, (void *) args, 0);
838                 if (pid < 0) {
839                         /* the fork failed */
840                         if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
841                             atomic_dec_return(&part->nchannels_engaged) == 0) {
842                                 xpc_mark_partition_disengaged(part);
843                                 xpc_IPI_send_disengage(part);
844                         }
845                         xpc_msgqueue_deref(ch);
846                         xpc_part_deref(part);
847
848                         if (atomic_read(&ch->kthreads_assigned) <
849                                                 ch->kthreads_idle_limit) {
850                                 /*
851                                  * Flag this as an error only if we have an
852                                  * insufficient #of kthreads for the channel
853                                  * to function.
854                                  *
855                                  * No xpc_msgqueue_ref() is needed here since
856                                  * the channel mgr is doing this.
857                                  */
858                                 spin_lock_irqsave(&ch->lock, irq_flags);
859                                 XPC_DISCONNECT_CHANNEL(ch, xpcLackOfResources,
860                                                                 &irq_flags);
861                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
862                         }
863                         break;
864                 }
865
866                 ch->kthreads_created++; // >>> temporary debug only!!!
867         }
868 }
869
870
871 void
872 xpc_disconnect_wait(int ch_number)
873 {
874         unsigned long irq_flags;
875         partid_t partid;
876         struct xpc_partition *part;
877         struct xpc_channel *ch;
878         int wakeup_channel_mgr;
879
880
881         /* now wait for all callouts to the caller's function to cease */
882         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
883                 part = &xpc_partitions[partid];
884
885                 if (!xpc_part_ref(part)) {
886                         continue;
887                 }
888
889                 ch = &part->channels[ch_number];
890
891                 if (!(ch->flags & XPC_C_WDISCONNECT)) {
892                         xpc_part_deref(part);
893                         continue;
894                 }
895
896                 (void) down(&ch->wdisconnect_sema);
897
898                 spin_lock_irqsave(&ch->lock, irq_flags);
899                 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
900                 wakeup_channel_mgr = 0;
901
902                 if (ch->delayed_IPI_flags) {
903                         if (part->act_state != XPC_P_DEACTIVATING) {
904                                 spin_lock(&part->IPI_lock);
905                                 XPC_SET_IPI_FLAGS(part->local_IPI_amo,
906                                         ch->number, ch->delayed_IPI_flags);
907                                 spin_unlock(&part->IPI_lock);
908                                 wakeup_channel_mgr = 1;
909                         }
910                         ch->delayed_IPI_flags = 0;
911                 }
912
913                 ch->flags &= ~XPC_C_WDISCONNECT;
914                 spin_unlock_irqrestore(&ch->lock, irq_flags);
915
916                 if (wakeup_channel_mgr) {
917                         xpc_wakeup_channel_mgr(part);
918                 }
919
920                 xpc_part_deref(part);
921         }
922 }
923
924
925 static void
926 xpc_do_exit(enum xpc_retval reason)
927 {
928         partid_t partid;
929         int active_part_count, printed_waiting_msg = 0;
930         struct xpc_partition *part;
931         unsigned long printmsg_time, disengage_request_timeout = 0;
932
933
934         /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
935         DBUG_ON(xpc_exiting == 1);
936
937         /*
938          * Let the heartbeat checker thread and the discovery thread
939          * (if one is running) know that they should exit. Also wake up
940          * the heartbeat checker thread in case it's sleeping.
941          */
942         xpc_exiting = 1;
943         wake_up_interruptible(&xpc_act_IRQ_wq);
944
945         /* ignore all incoming interrupts */
946         free_irq(SGI_XPC_ACTIVATE, NULL);
947
948         /* wait for the discovery thread to exit */
949         down(&xpc_discovery_exited);
950
951         /* wait for the heartbeat checker thread to exit */
952         down(&xpc_hb_checker_exited);
953
954
955         /* sleep for a 1/3 of a second or so */
956         (void) msleep_interruptible(300);
957
958
959         /* wait for all partitions to become inactive */
960
961         printmsg_time = jiffies + (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
962         xpc_disengage_request_timedout = 0;
963
964         do {
965                 active_part_count = 0;
966
967                 for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
968                         part = &xpc_partitions[partid];
969
970                         if (xpc_partition_disengaged(part) &&
971                                         part->act_state == XPC_P_INACTIVE) {
972                                 continue;
973                         }
974
975                         active_part_count++;
976
977                         XPC_DEACTIVATE_PARTITION(part, reason);
978
979                         if (part->disengage_request_timeout >
980                                                 disengage_request_timeout) {
981                                 disengage_request_timeout =
982                                                 part->disengage_request_timeout;
983                         }
984                 }
985
986                 if (xpc_partition_engaged(-1UL)) {
987                         if (time_after(jiffies, printmsg_time)) {
988                                 dev_info(xpc_part, "waiting for remote "
989                                         "partitions to disengage, timeout in "
990                                         "%ld seconds\n",
991                                         (disengage_request_timeout - jiffies)
992                                                                         / HZ);
993                                 printmsg_time = jiffies +
994                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL * HZ);
995                                 printed_waiting_msg = 1;
996                         }
997
998                 } else if (active_part_count > 0) {
999                         if (printed_waiting_msg) {
1000                                 dev_info(xpc_part, "waiting for local partition"
1001                                         " to disengage\n");
1002                                 printed_waiting_msg = 0;
1003                         }
1004
1005                 } else {
1006                         if (!xpc_disengage_request_timedout) {
1007                                 dev_info(xpc_part, "all partitions have "
1008                                         "disengaged\n");
1009                         }
1010                         break;
1011                 }
1012
1013                 /* sleep for a 1/3 of a second or so */
1014                 (void) msleep_interruptible(300);
1015
1016         } while (1);
1017
1018         DBUG_ON(xpc_partition_engaged(-1UL));
1019
1020
1021         /* indicate to others that our reserved page is uninitialized */
1022         xpc_rsvd_page->vars_pa = 0;
1023
1024         /* now it's time to eliminate our heartbeat */
1025         del_timer_sync(&xpc_hb_timer);
1026         DBUG_ON(xpc_vars->heartbeating_to_mask != 0);
1027
1028         if (reason == xpcUnloading) {
1029                 /* take ourselves off of the reboot_notifier_list */
1030                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1031
1032                 /* take ourselves off of the die_notifier list */
1033                 (void) unregister_die_notifier(&xpc_die_notifier);
1034         }
1035
1036         /* close down protections for IPI operations */
1037         xpc_restrict_IPI_ops();
1038
1039
1040         /* clear the interface to XPC's functions */
1041         xpc_clear_interface();
1042
1043         if (xpc_sysctl) {
1044                 unregister_sysctl_table(xpc_sysctl);
1045         }
1046 }
1047
1048
1049 /*
1050  * This function is called when the system is being rebooted.
1051  */
1052 static int
1053 xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1054 {
1055         enum xpc_retval reason;
1056
1057
1058         switch (event) {
1059         case SYS_RESTART:
1060                 reason = xpcSystemReboot;
1061                 break;
1062         case SYS_HALT:
1063                 reason = xpcSystemHalt;
1064                 break;
1065         case SYS_POWER_OFF:
1066                 reason = xpcSystemPoweroff;
1067                 break;
1068         default:
1069                 reason = xpcSystemGoingDown;
1070         }
1071
1072         xpc_do_exit(reason);
1073         return NOTIFY_DONE;
1074 }
1075
1076
1077 /*
1078  * Notify other partitions to disengage from all references to our memory.
1079  */
1080 static void
1081 xpc_die_disengage(void)
1082 {
1083         struct xpc_partition *part;
1084         partid_t partid;
1085         unsigned long engaged;
1086         long time, printmsg_time, disengage_request_timeout;
1087
1088
1089         /* keep xpc_hb_checker thread from doing anything (just in case) */
1090         xpc_exiting = 1;
1091
1092         xpc_vars->heartbeating_to_mask = 0;  /* indicate we're deactivated */
1093
1094         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1095                 part = &xpc_partitions[partid];
1096
1097                 if (!XPC_SUPPORTS_DISENGAGE_REQUEST(part->
1098                                                         remote_vars_version)) {
1099
1100                         /* just in case it was left set by an earlier XPC */
1101                         xpc_clear_partition_engaged(1UL << partid);
1102                         continue;
1103                 }
1104
1105                 if (xpc_partition_engaged(1UL << partid) ||
1106                                         part->act_state != XPC_P_INACTIVE) {
1107                         xpc_request_partition_disengage(part);
1108                         xpc_mark_partition_disengaged(part);
1109                         xpc_IPI_send_disengage(part);
1110                 }
1111         }
1112
1113         time = rtc_time();
1114         printmsg_time = time +
1115                 (XPC_DISENGAGE_PRINTMSG_INTERVAL * sn_rtc_cycles_per_second);
1116         disengage_request_timeout = time +
1117                 (xpc_disengage_request_timelimit * sn_rtc_cycles_per_second);
1118
1119         /* wait for all other partitions to disengage from us */
1120
1121         while (1) {
1122                 engaged = xpc_partition_engaged(-1UL);
1123                 if (!engaged) {
1124                         dev_info(xpc_part, "all partitions have disengaged\n");
1125                         break;
1126                 }
1127
1128                 time = rtc_time();
1129                 if (time >= disengage_request_timeout) {
1130                         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1131                                 if (engaged & (1UL << partid)) {
1132                                         dev_info(xpc_part, "disengage from "
1133                                                 "remote partition %d timed "
1134                                                 "out\n", partid);
1135                                 }
1136                         }
1137                         break;
1138                 }
1139
1140                 if (time >= printmsg_time) {
1141                         dev_info(xpc_part, "waiting for remote partitions to "
1142                                 "disengage, timeout in %ld seconds\n",
1143                                 (disengage_request_timeout - time) /
1144                                                 sn_rtc_cycles_per_second);
1145                         printmsg_time = time +
1146                                         (XPC_DISENGAGE_PRINTMSG_INTERVAL *
1147                                                 sn_rtc_cycles_per_second);
1148                 }
1149         }
1150 }
1151
1152
1153 /*
1154  * This function is called when the system is being restarted or halted due
1155  * to some sort of system failure. If this is the case we need to notify the
1156  * other partitions to disengage from all references to our memory.
1157  * This function can also be called when our heartbeater could be offlined
1158  * for a time. In this case we need to notify other partitions to not worry
1159  * about the lack of a heartbeat.
1160  */
1161 static int
1162 xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1163 {
1164         switch (event) {
1165         case DIE_MACHINE_RESTART:
1166         case DIE_MACHINE_HALT:
1167                 xpc_die_disengage();
1168                 break;
1169
1170         case DIE_KDEBUG_ENTER:
1171                 /* Should lack of heartbeat be ignored by other partitions? */
1172                 if (!xpc_kdebug_ignore) {
1173                         break;
1174                 }
1175                 /* fall through */
1176         case DIE_MCA_MONARCH_ENTER:
1177         case DIE_INIT_MONARCH_ENTER:
1178                 xpc_vars->heartbeat++;
1179                 xpc_vars->heartbeat_offline = 1;
1180                 break;
1181
1182         case DIE_KDEBUG_LEAVE:
1183                 /* Is lack of heartbeat being ignored by other partitions? */
1184                 if (!xpc_kdebug_ignore) {
1185                         break;
1186                 }
1187                 /* fall through */
1188         case DIE_MCA_MONARCH_LEAVE:
1189         case DIE_INIT_MONARCH_LEAVE:
1190                 xpc_vars->heartbeat++;
1191                 xpc_vars->heartbeat_offline = 0;
1192                 break;
1193         }
1194
1195         return NOTIFY_DONE;
1196 }
1197
1198
1199 int __init
1200 xpc_init(void)
1201 {
1202         int ret;
1203         partid_t partid;
1204         struct xpc_partition *part;
1205         pid_t pid;
1206
1207
1208         if (!ia64_platform_is("sn2")) {
1209                 return -ENODEV;
1210         }
1211
1212         /*
1213          * xpc_remote_copy_buffer is used as a temporary buffer for bte_copy'ng
1214          * various portions of a partition's reserved page. Its size is based
1215          * on the size of the reserved page header and part_nasids mask. So we
1216          * need to ensure that the other items will fit as well.
1217          */
1218         if (XPC_RP_VARS_SIZE > XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES) {
1219                 dev_err(xpc_part, "xpc_remote_copy_buffer is not big enough\n");
1220                 return -EPERM;
1221         }
1222         DBUG_ON((u64) xpc_remote_copy_buffer !=
1223                                 L1_CACHE_ALIGN((u64) xpc_remote_copy_buffer));
1224
1225         snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
1226         snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
1227
1228         xpc_sysctl = register_sysctl_table(xpc_sys_dir, 1);
1229
1230         /*
1231          * The first few fields of each entry of xpc_partitions[] need to
1232          * be initialized now so that calls to xpc_connect() and
1233          * xpc_disconnect() can be made prior to the activation of any remote
1234          * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
1235          * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
1236          * PARTITION HAS BEEN ACTIVATED.
1237          */
1238         for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
1239                 part = &xpc_partitions[partid];
1240
1241                 DBUG_ON((u64) part != L1_CACHE_ALIGN((u64) part));
1242
1243                 part->act_IRQ_rcvd = 0;
1244                 spin_lock_init(&part->act_lock);
1245                 part->act_state = XPC_P_INACTIVE;
1246                 XPC_SET_REASON(part, 0, 0);
1247
1248                 init_timer(&part->disengage_request_timer);
1249                 part->disengage_request_timer.function =
1250                                 xpc_timeout_partition_disengage_request;
1251                 part->disengage_request_timer.data = (unsigned long) part;
1252
1253                 part->setup_state = XPC_P_UNSET;
1254                 init_waitqueue_head(&part->teardown_wq);
1255                 atomic_set(&part->references, 0);
1256         }
1257
1258         /*
1259          * Open up protections for IPI operations (and AMO operations on
1260          * Shub 1.1 systems).
1261          */
1262         xpc_allow_IPI_ops();
1263
1264         /*
1265          * Interrupts being processed will increment this atomic variable and
1266          * awaken the heartbeat thread which will process the interrupts.
1267          */
1268         atomic_set(&xpc_act_IRQ_rcvd, 0);
1269
1270         /*
1271          * This is safe to do before the xpc_hb_checker thread has started
1272          * because the handler releases a wait queue.  If an interrupt is
1273          * received before the thread is waiting, it will not go to sleep,
1274          * but rather immediately process the interrupt.
1275          */
1276         ret = request_irq(SGI_XPC_ACTIVATE, xpc_act_IRQ_handler, 0,
1277                                                         "xpc hb", NULL);
1278         if (ret != 0) {
1279                 dev_err(xpc_part, "can't register ACTIVATE IRQ handler, "
1280                         "errno=%d\n", -ret);
1281
1282                 xpc_restrict_IPI_ops();
1283
1284                 if (xpc_sysctl) {
1285                         unregister_sysctl_table(xpc_sysctl);
1286                 }
1287                 return -EBUSY;
1288         }
1289
1290         /*
1291          * Fill the partition reserved page with the information needed by
1292          * other partitions to discover we are alive and establish initial
1293          * communications.
1294          */
1295         xpc_rsvd_page = xpc_rsvd_page_init();
1296         if (xpc_rsvd_page == NULL) {
1297                 dev_err(xpc_part, "could not setup our reserved page\n");
1298
1299                 free_irq(SGI_XPC_ACTIVATE, NULL);
1300                 xpc_restrict_IPI_ops();
1301
1302                 if (xpc_sysctl) {
1303                         unregister_sysctl_table(xpc_sysctl);
1304                 }
1305                 return -EBUSY;
1306         }
1307
1308
1309         /* add ourselves to the reboot_notifier_list */
1310         ret = register_reboot_notifier(&xpc_reboot_notifier);
1311         if (ret != 0) {
1312                 dev_warn(xpc_part, "can't register reboot notifier\n");
1313         }
1314
1315         /* add ourselves to the die_notifier list (i.e., ia64die_chain) */
1316         ret = register_die_notifier(&xpc_die_notifier);
1317         if (ret != 0) {
1318                 dev_warn(xpc_part, "can't register die notifier\n");
1319         }
1320
1321
1322         /*
1323          * Set the beating to other partitions into motion.  This is
1324          * the last requirement for other partitions' discovery to
1325          * initiate communications with us.
1326          */
1327         init_timer(&xpc_hb_timer);
1328         xpc_hb_timer.function = xpc_hb_beater;
1329         xpc_hb_beater(0);
1330
1331
1332         /*
1333          * The real work-horse behind xpc.  This processes incoming
1334          * interrupts and monitors remote heartbeats.
1335          */
1336         pid = kernel_thread(xpc_hb_checker, NULL, 0);
1337         if (pid < 0) {
1338                 dev_err(xpc_part, "failed while forking hb check thread\n");
1339
1340                 /* indicate to others that our reserved page is uninitialized */
1341                 xpc_rsvd_page->vars_pa = 0;
1342
1343                 /* take ourselves off of the reboot_notifier_list */
1344                 (void) unregister_reboot_notifier(&xpc_reboot_notifier);
1345
1346                 /* take ourselves off of the die_notifier list */
1347                 (void) unregister_die_notifier(&xpc_die_notifier);
1348
1349                 del_timer_sync(&xpc_hb_timer);
1350                 free_irq(SGI_XPC_ACTIVATE, NULL);
1351                 xpc_restrict_IPI_ops();
1352
1353                 if (xpc_sysctl) {
1354                         unregister_sysctl_table(xpc_sysctl);
1355                 }
1356                 return -EBUSY;
1357         }
1358
1359
1360         /*
1361          * Startup a thread that will attempt to discover other partitions to
1362          * activate based on info provided by SAL. This new thread is short
1363          * lived and will exit once discovery is complete.
1364          */
1365         pid = kernel_thread(xpc_initiate_discovery, NULL, 0);
1366         if (pid < 0) {
1367                 dev_err(xpc_part, "failed while forking discovery thread\n");
1368
1369                 /* mark this new thread as a non-starter */
1370                 up(&xpc_discovery_exited);
1371
1372                 xpc_do_exit(xpcUnloading);
1373                 return -EBUSY;
1374         }
1375
1376
1377         /* set the interface to point at XPC's functions */
1378         xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1379                           xpc_initiate_allocate, xpc_initiate_send,
1380                           xpc_initiate_send_notify, xpc_initiate_received,
1381                           xpc_initiate_partid_to_nasids);
1382
1383         return 0;
1384 }
1385 module_init(xpc_init);
1386
1387
1388 void __exit
1389 xpc_exit(void)
1390 {
1391         xpc_do_exit(xpcUnloading);
1392 }
1393 module_exit(xpc_exit);
1394
1395
1396 MODULE_AUTHOR("Silicon Graphics, Inc.");
1397 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1398 MODULE_LICENSE("GPL");
1399
1400 module_param(xpc_hb_interval, int, 0);
1401 MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1402                 "heartbeat increments.");
1403
1404 module_param(xpc_hb_check_interval, int, 0);
1405 MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1406                 "heartbeat checks.");
1407
1408 module_param(xpc_disengage_request_timelimit, int, 0);
1409 MODULE_PARM_DESC(xpc_disengage_request_timelimit, "Number of seconds to wait "
1410                 "for disengage request to complete.");
1411
1412 module_param(xpc_kdebug_ignore, int, 0);
1413 MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1414                 "other partitions when dropping into kdebug.");
1415