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
6 * Copyright (c) 2004-2008 Silicon Graphics, Inc. All Rights Reserved.
10 * Cross Partition Communication (XPC) support - standard version.
12 * XPC provides a message passing capability that crosses partition
13 * boundaries. This module is made up of two parts:
15 * partition This part detects the presence/absence of other
16 * partitions. It provides a heartbeat and monitors
17 * the heartbeats of other partitions.
19 * channel This part manages the channels and sends/receives
20 * messages across them to/from other partitions.
22 * There are a couple of additional functions residing in XP, which
23 * provide an interface to XPC for its users.
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.
41 * If/when new hardware solves this IPI problem, we should abandon
42 * the current approach.
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>
55 /* define two XPC debug device structures to be used with dev_dbg() et al */
57 struct device_driver xpc_dbg_name = {
61 struct device xpc_part_dbg_subname = {
62 .bus_id = {0}, /* set to "part" at xpc_init() time */
63 .driver = &xpc_dbg_name
66 struct device xpc_chan_dbg_subname = {
67 .bus_id = {0}, /* set to "chan" at xpc_init() time */
68 .driver = &xpc_dbg_name
71 struct device *xpc_part = &xpc_part_dbg_subname;
72 struct device *xpc_chan = &xpc_chan_dbg_subname;
74 static int xpc_kdebug_ignore;
76 /* systune related variables for /proc/sys directories */
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;
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;
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;
90 static ctl_table xpc_sys_xpc_hb_dir[] = {
92 .ctl_name = CTL_UNNUMBERED,
93 .procname = "hb_interval",
94 .data = &xpc_hb_interval,
95 .maxlen = sizeof(int),
97 .proc_handler = &proc_dointvec_minmax,
98 .strategy = &sysctl_intvec,
99 .extra1 = &xpc_hb_min_interval,
100 .extra2 = &xpc_hb_max_interval},
102 .ctl_name = CTL_UNNUMBERED,
103 .procname = "hb_check_interval",
104 .data = &xpc_hb_check_interval,
105 .maxlen = sizeof(int),
107 .proc_handler = &proc_dointvec_minmax,
108 .strategy = &sysctl_intvec,
109 .extra1 = &xpc_hb_check_min_interval,
110 .extra2 = &xpc_hb_check_max_interval},
113 static ctl_table xpc_sys_xpc_dir[] = {
115 .ctl_name = CTL_UNNUMBERED,
118 .child = xpc_sys_xpc_hb_dir},
120 .ctl_name = CTL_UNNUMBERED,
121 .procname = "disengage_timelimit",
122 .data = &xpc_disengage_timelimit,
123 .maxlen = sizeof(int),
125 .proc_handler = &proc_dointvec_minmax,
126 .strategy = &sysctl_intvec,
127 .extra1 = &xpc_disengage_min_timelimit,
128 .extra2 = &xpc_disengage_max_timelimit},
131 static ctl_table xpc_sys_dir[] = {
133 .ctl_name = CTL_UNNUMBERED,
136 .child = xpc_sys_xpc_dir},
139 static struct ctl_table_header *xpc_sysctl;
141 /* non-zero if any remote partition disengage was timed out */
142 int xpc_disengage_timedout;
144 /* #of activate IRQs received */
145 atomic_t xpc_activate_IRQ_rcvd = ATOMIC_INIT(0);
147 /* IRQ handler notifies this wait queue on receipt of an IRQ */
148 DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq);
150 static unsigned long xpc_hb_check_timeout;
151 static struct timer_list xpc_hb_timer;
152 void *xpc_heartbeating_to_mask;
154 /* notification that the xpc_hb_checker thread has exited */
155 static DECLARE_COMPLETION(xpc_hb_checker_exited);
157 /* notification that the xpc_discovery thread has exited */
158 static DECLARE_COMPLETION(xpc_discovery_exited);
160 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
162 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
163 static struct notifier_block xpc_reboot_notifier = {
164 .notifier_call = xpc_system_reboot,
167 static int xpc_system_die(struct notifier_block *, unsigned long, void *);
168 static struct notifier_block xpc_die_notifier = {
169 .notifier_call = xpc_system_die,
172 enum xp_retval (*xpc_get_partition_rsvd_page_pa) (void *buf, u64 *cookie,
173 unsigned long *rp_pa,
175 enum xp_retval (*xpc_rsvd_page_init) (struct xpc_rsvd_page *rp);
176 void (*xpc_heartbeat_init) (void);
177 void (*xpc_heartbeat_exit) (void);
178 void (*xpc_increment_heartbeat) (void);
179 void (*xpc_offline_heartbeat) (void);
180 void (*xpc_online_heartbeat) (void);
181 enum xp_retval (*xpc_get_remote_heartbeat) (struct xpc_partition *part);
183 enum xp_retval (*xpc_make_first_contact) (struct xpc_partition *part);
184 void (*xpc_notify_senders_of_disconnect) (struct xpc_channel *ch);
185 u64 (*xpc_get_chctl_all_flags) (struct xpc_partition *part);
186 enum xp_retval (*xpc_allocate_msgqueues) (struct xpc_channel *ch);
187 void (*xpc_free_msgqueues) (struct xpc_channel *ch);
188 void (*xpc_process_msg_chctl_flags) (struct xpc_partition *part, int ch_number);
189 int (*xpc_n_of_deliverable_msgs) (struct xpc_channel *ch);
190 struct xpc_msg *(*xpc_get_deliverable_msg) (struct xpc_channel *ch);
192 void (*xpc_request_partition_activation) (struct xpc_rsvd_page *remote_rp,
193 unsigned long remote_rp_pa,
195 void (*xpc_request_partition_reactivation) (struct xpc_partition *part);
196 void (*xpc_request_partition_deactivation) (struct xpc_partition *part);
197 void (*xpc_cancel_partition_deactivation_request) (struct xpc_partition *part);
199 void (*xpc_process_activate_IRQ_rcvd) (int n_IRQs_expected);
200 enum xp_retval (*xpc_setup_infrastructure) (struct xpc_partition *part);
201 void (*xpc_teardown_infrastructure) (struct xpc_partition *part);
203 void (*xpc_indicate_partition_engaged) (struct xpc_partition *part);
204 int (*xpc_partition_engaged) (short partid);
205 int (*xpc_any_partition_engaged) (void);
206 void (*xpc_indicate_partition_disengaged) (struct xpc_partition *part);
207 void (*xpc_assume_partition_disengaged) (short partid);
209 void (*xpc_send_chctl_closerequest) (struct xpc_channel *ch,
210 unsigned long *irq_flags);
211 void (*xpc_send_chctl_closereply) (struct xpc_channel *ch,
212 unsigned long *irq_flags);
213 void (*xpc_send_chctl_openrequest) (struct xpc_channel *ch,
214 unsigned long *irq_flags);
215 void (*xpc_send_chctl_openreply) (struct xpc_channel *ch,
216 unsigned long *irq_flags);
218 enum xp_retval (*xpc_send_msg) (struct xpc_channel *ch, u32 flags,
219 void *payload, u16 payload_size, u8 notify_type,
220 xpc_notify_func func, void *key);
221 void (*xpc_received_msg) (struct xpc_channel *ch, struct xpc_msg *msg);
224 * Timer function to enforce the timelimit on the partition disengage.
227 xpc_timeout_partition_disengage(unsigned long data)
229 struct xpc_partition *part = (struct xpc_partition *)data;
231 DBUG_ON(time_is_after_jiffies(part->disengage_timeout));
233 (void)xpc_partition_disengaged(part);
235 DBUG_ON(part->disengage_timeout != 0);
236 DBUG_ON(xpc_partition_engaged(XPC_PARTID(part)));
240 * Timer to produce the heartbeat. The timer structures function is
241 * already set when this is initially called. A tunable is used to
242 * specify when the next timeout should occur.
245 xpc_hb_beater(unsigned long dummy)
247 xpc_increment_heartbeat();
249 if (time_is_before_eq_jiffies(xpc_hb_check_timeout))
250 wake_up_interruptible(&xpc_activate_IRQ_wq);
252 xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
253 add_timer(&xpc_hb_timer);
257 xpc_start_hb_beater(void)
259 xpc_heartbeat_init();
260 init_timer(&xpc_hb_timer);
261 xpc_hb_timer.function = xpc_hb_beater;
266 xpc_stop_hb_beater(void)
268 del_timer_sync(&xpc_hb_timer);
269 xpc_heartbeat_exit();
273 * At periodic intervals, scan through all active partitions and ensure
274 * their heartbeat is still active. If not, the partition is deactivated.
277 xpc_check_remote_hb(void)
279 struct xpc_partition *part;
283 for (partid = 0; partid < xp_max_npartitions; partid++) {
288 if (partid == xp_partition_id)
291 part = &xpc_partitions[partid];
293 if (part->act_state == XPC_P_INACTIVE ||
294 part->act_state == XPC_P_DEACTIVATING) {
298 ret = xpc_get_remote_heartbeat(part);
299 if (ret != xpSuccess)
300 XPC_DEACTIVATE_PARTITION(part, ret);
305 * This thread is responsible for nearly all of the partition
306 * activation/deactivation.
309 xpc_hb_checker(void *ignore)
311 int last_IRQ_count = 0;
315 /* this thread was marked active by xpc_hb_init() */
317 set_cpus_allowed_ptr(current, &cpumask_of_cpu(XPC_HB_CHECK_CPU));
319 /* set our heartbeating to other partitions into motion */
320 xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
321 xpc_start_hb_beater();
323 while (!xpc_exiting) {
325 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
327 (int)(xpc_hb_check_timeout - jiffies),
328 atomic_read(&xpc_activate_IRQ_rcvd) - last_IRQ_count);
330 /* checking of remote heartbeats is skewed by IRQ handling */
331 if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) {
332 dev_dbg(xpc_part, "checking remote heartbeats\n");
333 xpc_check_remote_hb();
336 * We need to periodically recheck to ensure no
337 * IRQ/amo pairs have been missed. That check
338 * must always reset xpc_hb_check_timeout.
343 /* check for outstanding IRQs */
344 new_IRQ_count = atomic_read(&xpc_activate_IRQ_rcvd);
345 if (last_IRQ_count < new_IRQ_count || force_IRQ != 0) {
348 dev_dbg(xpc_part, "found an IRQ to process; will be "
349 "resetting xpc_hb_check_timeout\n");
351 xpc_process_activate_IRQ_rcvd(new_IRQ_count -
353 last_IRQ_count = new_IRQ_count;
355 xpc_hb_check_timeout = jiffies +
356 (xpc_hb_check_interval * HZ);
359 /* wait for IRQ or timeout */
360 (void)wait_event_interruptible(xpc_activate_IRQ_wq,
361 (last_IRQ_count < atomic_read(
362 &xpc_activate_IRQ_rcvd)
363 || time_is_before_eq_jiffies(
364 xpc_hb_check_timeout) ||
368 xpc_stop_hb_beater();
370 dev_dbg(xpc_part, "heartbeat checker is exiting\n");
372 /* mark this thread as having exited */
373 complete(&xpc_hb_checker_exited);
378 * This thread will attempt to discover other partitions to activate
379 * based on info provided by SAL. This new thread is short lived and
380 * will exit once discovery is complete.
383 xpc_initiate_discovery(void *ignore)
387 dev_dbg(xpc_part, "discovery thread is exiting\n");
389 /* mark this thread as having exited */
390 complete(&xpc_discovery_exited);
395 * The first kthread assigned to a newly activated partition is the one
396 * created by XPC HB with which it calls xpc_activating(). XPC hangs on to
397 * that kthread until the partition is brought down, at which time that kthread
398 * returns back to XPC HB. (The return of that kthread will signify to XPC HB
399 * that XPC has dismantled all communication infrastructure for the associated
400 * partition.) This kthread becomes the channel manager for that partition.
402 * Each active partition has a channel manager, who, besides connecting and
403 * disconnecting channels, will ensure that each of the partition's connected
404 * channels has the required number of assigned kthreads to get the work done.
407 xpc_channel_mgr(struct xpc_partition *part)
409 while (part->act_state != XPC_P_DEACTIVATING ||
410 atomic_read(&part->nchannels_active) > 0 ||
411 !xpc_partition_disengaged(part)) {
413 xpc_process_sent_chctl_flags(part);
416 * Wait until we've been requested to activate kthreads or
417 * all of the channel's message queues have been torn down or
418 * a signal is pending.
420 * The channel_mgr_requests is set to 1 after being awakened,
421 * This is done to prevent the channel mgr from making one pass
422 * through the loop for each request, since he will
423 * be servicing all the requests in one pass. The reason it's
424 * set to 1 instead of 0 is so that other kthreads will know
425 * that the channel mgr is running and won't bother trying to
428 atomic_dec(&part->channel_mgr_requests);
429 (void)wait_event_interruptible(part->channel_mgr_wq,
430 (atomic_read(&part->channel_mgr_requests) > 0 ||
431 part->chctl.all_flags != 0 ||
432 (part->act_state == XPC_P_DEACTIVATING &&
433 atomic_read(&part->nchannels_active) == 0 &&
434 xpc_partition_disengaged(part))));
435 atomic_set(&part->channel_mgr_requests, 1);
440 * When XPC HB determines that a partition has come up, it will create a new
441 * kthread and that kthread will call this function to attempt to set up the
442 * basic infrastructure used for Cross Partition Communication with the newly
445 * The kthread that was created by XPC HB and which setup the XPC
446 * infrastructure will remain assigned to the partition becoming the channel
447 * manager for that partition until the partition is deactivating, at which
448 * time the kthread will teardown the XPC infrastructure and then exit.
451 xpc_activating(void *__partid)
453 short partid = (u64)__partid;
454 struct xpc_partition *part = &xpc_partitions[partid];
455 unsigned long irq_flags;
457 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
459 spin_lock_irqsave(&part->act_lock, irq_flags);
461 if (part->act_state == XPC_P_DEACTIVATING) {
462 part->act_state = XPC_P_INACTIVE;
463 spin_unlock_irqrestore(&part->act_lock, irq_flags);
464 part->remote_rp_pa = 0;
468 /* indicate the thread is activating */
469 DBUG_ON(part->act_state != XPC_P_ACTIVATION_REQ);
470 part->act_state = XPC_P_ACTIVATING;
472 XPC_SET_REASON(part, 0, 0);
473 spin_unlock_irqrestore(&part->act_lock, irq_flags);
475 dev_dbg(xpc_part, "activating partition %d\n", partid);
477 xpc_allow_hb(partid);
479 if (xpc_setup_infrastructure(part) == xpSuccess) {
480 (void)xpc_part_ref(part); /* this will always succeed */
482 if (xpc_make_first_contact(part) == xpSuccess) {
483 xpc_mark_partition_active(part);
484 xpc_channel_mgr(part);
485 /* won't return until partition is deactivating */
488 xpc_part_deref(part);
489 xpc_teardown_infrastructure(part);
492 xpc_disallow_hb(partid);
493 xpc_mark_partition_inactive(part);
495 if (part->reason == xpReactivating) {
496 /* interrupting ourselves results in activating partition */
497 xpc_request_partition_reactivation(part);
504 xpc_activate_partition(struct xpc_partition *part)
506 short partid = XPC_PARTID(part);
507 unsigned long irq_flags;
508 struct task_struct *kthread;
510 spin_lock_irqsave(&part->act_lock, irq_flags);
512 DBUG_ON(part->act_state != XPC_P_INACTIVE);
514 part->act_state = XPC_P_ACTIVATION_REQ;
515 XPC_SET_REASON(part, xpCloneKThread, __LINE__);
517 spin_unlock_irqrestore(&part->act_lock, irq_flags);
519 kthread = kthread_run(xpc_activating, (void *)((u64)partid), "xpc%02d",
521 if (IS_ERR(kthread)) {
522 spin_lock_irqsave(&part->act_lock, irq_flags);
523 part->act_state = XPC_P_INACTIVE;
524 XPC_SET_REASON(part, xpCloneKThreadFailed, __LINE__);
525 spin_unlock_irqrestore(&part->act_lock, irq_flags);
530 xpc_activate_kthreads(struct xpc_channel *ch, int needed)
532 int idle = atomic_read(&ch->kthreads_idle);
533 int assigned = atomic_read(&ch->kthreads_assigned);
536 DBUG_ON(needed <= 0);
539 wakeup = (needed > idle) ? idle : needed;
542 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
543 "channel=%d\n", wakeup, ch->partid, ch->number);
545 /* only wakeup the requested number of kthreads */
546 wake_up_nr(&ch->idle_wq, wakeup);
552 if (needed + assigned > ch->kthreads_assigned_limit) {
553 needed = ch->kthreads_assigned_limit - assigned;
558 dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
559 needed, ch->partid, ch->number);
561 xpc_create_kthreads(ch, needed, 0);
565 * This function is where XPC's kthreads wait for messages to deliver.
568 xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
571 /* deliver messages to their intended recipients */
573 while (xpc_n_of_deliverable_msgs(ch) > 0 &&
574 !(ch->flags & XPC_C_DISCONNECTING)) {
578 if (atomic_inc_return(&ch->kthreads_idle) >
579 ch->kthreads_idle_limit) {
580 /* too many idle kthreads on this channel */
581 atomic_dec(&ch->kthreads_idle);
585 dev_dbg(xpc_chan, "idle kthread calling "
586 "wait_event_interruptible_exclusive()\n");
588 (void)wait_event_interruptible_exclusive(ch->idle_wq,
589 (xpc_n_of_deliverable_msgs(ch) > 0 ||
590 (ch->flags & XPC_C_DISCONNECTING)));
592 atomic_dec(&ch->kthreads_idle);
594 } while (!(ch->flags & XPC_C_DISCONNECTING));
598 xpc_kthread_start(void *args)
600 short partid = XPC_UNPACK_ARG1(args);
601 u16 ch_number = XPC_UNPACK_ARG2(args);
602 struct xpc_partition *part = &xpc_partitions[partid];
603 struct xpc_channel *ch;
605 unsigned long irq_flags;
607 dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
610 ch = &part->channels[ch_number];
612 if (!(ch->flags & XPC_C_DISCONNECTING)) {
614 /* let registerer know that connection has been established */
616 spin_lock_irqsave(&ch->lock, irq_flags);
617 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
618 ch->flags |= XPC_C_CONNECTEDCALLOUT;
619 spin_unlock_irqrestore(&ch->lock, irq_flags);
621 xpc_connected_callout(ch);
623 spin_lock_irqsave(&ch->lock, irq_flags);
624 ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
625 spin_unlock_irqrestore(&ch->lock, irq_flags);
628 * It is possible that while the callout was being
629 * made that the remote partition sent some messages.
630 * If that is the case, we may need to activate
631 * additional kthreads to help deliver them. We only
632 * need one less than total #of messages to deliver.
634 n_needed = xpc_n_of_deliverable_msgs(ch) - 1;
635 if (n_needed > 0 && !(ch->flags & XPC_C_DISCONNECTING))
636 xpc_activate_kthreads(ch, n_needed);
639 spin_unlock_irqrestore(&ch->lock, irq_flags);
642 xpc_kthread_waitmsgs(part, ch);
645 /* let registerer know that connection is disconnecting */
647 spin_lock_irqsave(&ch->lock, irq_flags);
648 if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
649 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
650 ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
651 spin_unlock_irqrestore(&ch->lock, irq_flags);
653 xpc_disconnect_callout(ch, xpDisconnecting);
655 spin_lock_irqsave(&ch->lock, irq_flags);
656 ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
658 spin_unlock_irqrestore(&ch->lock, irq_flags);
660 if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
661 atomic_dec_return(&part->nchannels_engaged) == 0) {
662 xpc_indicate_partition_disengaged(part);
665 xpc_msgqueue_deref(ch);
667 dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
670 xpc_part_deref(part);
675 * For each partition that XPC has established communications with, there is
676 * a minimum of one kernel thread assigned to perform any operation that
677 * may potentially sleep or block (basically the callouts to the asynchronous
678 * functions registered via xpc_connect()).
680 * Additional kthreads are created and destroyed by XPC as the workload
683 * A kthread is assigned to one of the active channels that exists for a given
687 xpc_create_kthreads(struct xpc_channel *ch, int needed,
688 int ignore_disconnecting)
690 unsigned long irq_flags;
691 u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
692 struct xpc_partition *part = &xpc_partitions[ch->partid];
693 struct task_struct *kthread;
695 while (needed-- > 0) {
698 * The following is done on behalf of the newly created
699 * kthread. That kthread is responsible for doing the
700 * counterpart to the following before it exits.
702 if (ignore_disconnecting) {
703 if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
704 /* kthreads assigned had gone to zero */
706 XPC_C_DISCONNECTINGCALLOUT_MADE));
710 } else if (ch->flags & XPC_C_DISCONNECTING) {
713 } else if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
714 atomic_inc_return(&part->nchannels_engaged) == 1) {
715 xpc_indicate_partition_engaged(part);
717 (void)xpc_part_ref(part);
718 xpc_msgqueue_ref(ch);
720 kthread = kthread_run(xpc_kthread_start, (void *)args,
721 "xpc%02dc%d", ch->partid, ch->number);
722 if (IS_ERR(kthread)) {
723 /* the fork failed */
726 * NOTE: if (ignore_disconnecting &&
727 * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
728 * then we'll deadlock if all other kthreads assigned
729 * to this channel are blocked in the channel's
730 * registerer, because the only thing that will unblock
731 * them is the xpDisconnecting callout that this
732 * failed kthread_run() would have made.
735 if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
736 atomic_dec_return(&part->nchannels_engaged) == 0) {
737 xpc_indicate_partition_disengaged(part);
739 xpc_msgqueue_deref(ch);
740 xpc_part_deref(part);
742 if (atomic_read(&ch->kthreads_assigned) <
743 ch->kthreads_idle_limit) {
745 * Flag this as an error only if we have an
746 * insufficient #of kthreads for the channel
749 spin_lock_irqsave(&ch->lock, irq_flags);
750 XPC_DISCONNECT_CHANNEL(ch, xpLackOfResources,
752 spin_unlock_irqrestore(&ch->lock, irq_flags);
760 xpc_disconnect_wait(int ch_number)
762 unsigned long irq_flags;
764 struct xpc_partition *part;
765 struct xpc_channel *ch;
766 int wakeup_channel_mgr;
768 /* now wait for all callouts to the caller's function to cease */
769 for (partid = 0; partid < xp_max_npartitions; partid++) {
770 part = &xpc_partitions[partid];
772 if (!xpc_part_ref(part))
775 ch = &part->channels[ch_number];
777 if (!(ch->flags & XPC_C_WDISCONNECT)) {
778 xpc_part_deref(part);
782 wait_for_completion(&ch->wdisconnect_wait);
784 spin_lock_irqsave(&ch->lock, irq_flags);
785 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
786 wakeup_channel_mgr = 0;
788 if (ch->delayed_chctl_flags) {
789 if (part->act_state != XPC_P_DEACTIVATING) {
790 spin_lock(&part->chctl_lock);
791 part->chctl.flags[ch->number] |=
792 ch->delayed_chctl_flags;
793 spin_unlock(&part->chctl_lock);
794 wakeup_channel_mgr = 1;
796 ch->delayed_chctl_flags = 0;
799 ch->flags &= ~XPC_C_WDISCONNECT;
800 spin_unlock_irqrestore(&ch->lock, irq_flags);
802 if (wakeup_channel_mgr)
803 xpc_wakeup_channel_mgr(part);
805 xpc_part_deref(part);
810 xpc_do_exit(enum xp_retval reason)
813 int active_part_count, printed_waiting_msg = 0;
814 struct xpc_partition *part;
815 unsigned long printmsg_time, disengage_timeout = 0;
817 /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
818 DBUG_ON(xpc_exiting == 1);
821 * Let the heartbeat checker thread and the discovery thread
822 * (if one is running) know that they should exit. Also wake up
823 * the heartbeat checker thread in case it's sleeping.
826 wake_up_interruptible(&xpc_activate_IRQ_wq);
828 /* wait for the discovery thread to exit */
829 wait_for_completion(&xpc_discovery_exited);
831 /* wait for the heartbeat checker thread to exit */
832 wait_for_completion(&xpc_hb_checker_exited);
834 /* sleep for a 1/3 of a second or so */
835 (void)msleep_interruptible(300);
837 /* wait for all partitions to become inactive */
839 printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
840 xpc_disengage_timedout = 0;
843 active_part_count = 0;
845 for (partid = 0; partid < xp_max_npartitions; partid++) {
846 part = &xpc_partitions[partid];
848 if (xpc_partition_disengaged(part) &&
849 part->act_state == XPC_P_INACTIVE) {
855 XPC_DEACTIVATE_PARTITION(part, reason);
857 if (part->disengage_timeout > disengage_timeout)
858 disengage_timeout = part->disengage_timeout;
861 if (xpc_any_partition_engaged()) {
862 if (time_is_before_jiffies(printmsg_time)) {
863 dev_info(xpc_part, "waiting for remote "
864 "partitions to deactivate, timeout in "
865 "%ld seconds\n", (disengage_timeout -
867 printmsg_time = jiffies +
868 (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
869 printed_waiting_msg = 1;
872 } else if (active_part_count > 0) {
873 if (printed_waiting_msg) {
874 dev_info(xpc_part, "waiting for local partition"
876 printed_waiting_msg = 0;
880 if (!xpc_disengage_timedout) {
881 dev_info(xpc_part, "all partitions have "
887 /* sleep for a 1/3 of a second or so */
888 (void)msleep_interruptible(300);
892 DBUG_ON(xpc_any_partition_engaged());
893 DBUG_ON(xpc_any_hbs_allowed() != 0);
895 /* a zero timestamp indicates our rsvd page is not initialized */
896 xpc_rsvd_page->ts_jiffies = 0;
898 if (reason == xpUnloading) {
899 (void)unregister_die_notifier(&xpc_die_notifier);
900 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
903 /* clear the interface to XPC's functions */
904 xpc_clear_interface();
907 unregister_sysctl_table(xpc_sysctl);
909 kfree(xpc_partitions);
918 * This function is called when the system is being rebooted.
921 xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
923 enum xp_retval reason;
927 reason = xpSystemReboot;
930 reason = xpSystemHalt;
933 reason = xpSystemPoweroff;
936 reason = xpSystemGoingDown;
944 * Notify other partitions to deactivate from us by first disengaging from all
945 * references to our memory.
948 xpc_die_deactivate(void)
950 struct xpc_partition *part;
956 /* keep xpc_hb_checker thread from doing anything (just in case) */
959 xpc_disallow_all_hbs(); /*indicate we're deactivated */
961 for (partid = 0; partid < xp_max_npartitions; partid++) {
962 part = &xpc_partitions[partid];
964 if (xpc_partition_engaged(partid) ||
965 part->act_state != XPC_P_INACTIVE) {
966 xpc_request_partition_deactivation(part);
967 xpc_indicate_partition_disengaged(part);
972 * Though we requested that all other partitions deactivate from us,
973 * we only wait until they've all disengaged or we've reached the
976 * Given that one iteration through the following while-loop takes
977 * approximately 200 microseconds, calculate the #of loops to take
978 * before bailing and the #of loops before printing a waiting message.
980 keep_waiting = xpc_disengage_timelimit * 1000 * 5;
981 wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5;
984 any_engaged = xpc_any_partition_engaged();
986 dev_info(xpc_part, "all partitions have deactivated\n");
990 if (!keep_waiting--) {
991 for (partid = 0; partid < xp_max_npartitions;
993 if (xpc_partition_engaged(partid)) {
994 dev_info(xpc_part, "deactivate from "
995 "remote partition %d timed "
1002 if (!wait_to_print--) {
1003 dev_info(xpc_part, "waiting for remote partitions to "
1004 "deactivate, timeout in %ld seconds\n",
1005 keep_waiting / (1000 * 5));
1006 wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL *
1015 * This function is called when the system is being restarted or halted due
1016 * to some sort of system failure. If this is the case we need to notify the
1017 * other partitions to disengage from all references to our memory.
1018 * This function can also be called when our heartbeater could be offlined
1019 * for a time. In this case we need to notify other partitions to not worry
1020 * about the lack of a heartbeat.
1023 xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1025 #ifdef CONFIG_IA64 /* !!! temporary kludge */
1027 case DIE_MACHINE_RESTART:
1028 case DIE_MACHINE_HALT:
1029 xpc_die_deactivate();
1032 case DIE_KDEBUG_ENTER:
1033 /* Should lack of heartbeat be ignored by other partitions? */
1034 if (!xpc_kdebug_ignore)
1038 case DIE_MCA_MONARCH_ENTER:
1039 case DIE_INIT_MONARCH_ENTER:
1040 xpc_offline_heartbeat();
1043 case DIE_KDEBUG_LEAVE:
1044 /* Is lack of heartbeat being ignored by other partitions? */
1045 if (!xpc_kdebug_ignore)
1049 case DIE_MCA_MONARCH_LEAVE:
1050 case DIE_INIT_MONARCH_LEAVE:
1051 xpc_online_heartbeat();
1055 xpc_die_deactivate();
1066 struct xpc_partition *part;
1067 struct task_struct *kthread;
1069 snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
1070 snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
1074 * The ia64-sn2 architecture supports at most 64 partitions.
1075 * And the inability to unregister remote amos restricts us
1076 * further to only support exactly 64 partitions on this
1077 * architecture, no less.
1079 if (xp_max_npartitions != 64)
1082 ret = xpc_init_sn2();
1086 } else if (is_uv()) {
1093 xpc_partitions = kzalloc(sizeof(struct xpc_partition) *
1094 xp_max_npartitions, GFP_KERNEL);
1095 if (xpc_partitions == NULL) {
1096 dev_err(xpc_part, "can't get memory for partition structure\n");
1102 * The first few fields of each entry of xpc_partitions[] need to
1103 * be initialized now so that calls to xpc_connect() and
1104 * xpc_disconnect() can be made prior to the activation of any remote
1105 * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
1106 * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
1107 * PARTITION HAS BEEN ACTIVATED.
1109 for (partid = 0; partid < xp_max_npartitions; partid++) {
1110 part = &xpc_partitions[partid];
1112 DBUG_ON((u64)part != L1_CACHE_ALIGN((u64)part));
1114 part->activate_IRQ_rcvd = 0;
1115 spin_lock_init(&part->act_lock);
1116 part->act_state = XPC_P_INACTIVE;
1117 XPC_SET_REASON(part, 0, 0);
1119 init_timer(&part->disengage_timer);
1120 part->disengage_timer.function =
1121 xpc_timeout_partition_disengage;
1122 part->disengage_timer.data = (unsigned long)part;
1124 part->setup_state = XPC_P_UNSET;
1125 init_waitqueue_head(&part->teardown_wq);
1126 atomic_set(&part->references, 0);
1129 xpc_sysctl = register_sysctl_table(xpc_sys_dir);
1132 * Fill the partition reserved page with the information needed by
1133 * other partitions to discover we are alive and establish initial
1136 xpc_rsvd_page = xpc_setup_rsvd_page();
1137 if (xpc_rsvd_page == NULL) {
1138 dev_err(xpc_part, "can't setup our reserved page\n");
1143 /* add ourselves to the reboot_notifier_list */
1144 ret = register_reboot_notifier(&xpc_reboot_notifier);
1146 dev_warn(xpc_part, "can't register reboot notifier\n");
1148 /* add ourselves to the die_notifier list */
1149 ret = register_die_notifier(&xpc_die_notifier);
1151 dev_warn(xpc_part, "can't register die notifier\n");
1154 * The real work-horse behind xpc. This processes incoming
1155 * interrupts and monitors remote heartbeats.
1157 kthread = kthread_run(xpc_hb_checker, NULL, XPC_HB_CHECK_THREAD_NAME);
1158 if (IS_ERR(kthread)) {
1159 dev_err(xpc_part, "failed while forking hb check thread\n");
1165 * Startup a thread that will attempt to discover other partitions to
1166 * activate based on info provided by SAL. This new thread is short
1167 * lived and will exit once discovery is complete.
1169 kthread = kthread_run(xpc_initiate_discovery, NULL,
1170 XPC_DISCOVERY_THREAD_NAME);
1171 if (IS_ERR(kthread)) {
1172 dev_err(xpc_part, "failed while forking discovery thread\n");
1174 /* mark this new thread as a non-starter */
1175 complete(&xpc_discovery_exited);
1177 xpc_do_exit(xpUnloading);
1181 /* set the interface to point at XPC's functions */
1182 xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1183 xpc_initiate_send, xpc_initiate_send_notify,
1184 xpc_initiate_received, xpc_initiate_partid_to_nasids);
1188 /* initialization was not successful */
1190 /* a zero timestamp indicates our rsvd page is not initialized */
1191 xpc_rsvd_page->ts_jiffies = 0;
1193 (void)unregister_die_notifier(&xpc_die_notifier);
1194 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1197 unregister_sysctl_table(xpc_sysctl);
1198 kfree(xpc_partitions);
1207 module_init(xpc_init);
1212 xpc_do_exit(xpUnloading);
1215 module_exit(xpc_exit);
1217 MODULE_AUTHOR("Silicon Graphics, Inc.");
1218 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1219 MODULE_LICENSE("GPL");
1221 module_param(xpc_hb_interval, int, 0);
1222 MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1223 "heartbeat increments.");
1225 module_param(xpc_hb_check_interval, int, 0);
1226 MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1227 "heartbeat checks.");
1229 module_param(xpc_disengage_timelimit, int, 0);
1230 MODULE_PARM_DESC(xpc_disengage_timelimit, "Number of seconds to wait "
1231 "for disengage to complete.");
1233 module_param(xpc_kdebug_ignore, int, 0);
1234 MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1235 "other partitions when dropping into kdebug.");