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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) 2004-2009 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/slab.h>
48#include <linux/sysctl.h>
49#include <linux/device.h>
50#include <linux/delay.h>
51#include <linux/reboot.h>
52#include <linux/kdebug.h>
53#include <linux/kthread.h>
54#include "xpc.h"
55
56/* define two XPC debug device structures to be used with dev_dbg() et al */
57
58struct device_driver xpc_dbg_name = {
59 .name = "xpc"
60};
61
62struct device xpc_part_dbg_subname = {
63 .init_name = "", /* set to "part" at xpc_init() time */
64 .driver = &xpc_dbg_name
65};
66
67struct device xpc_chan_dbg_subname = {
68 .init_name = "", /* set to "chan" at xpc_init() time */
69 .driver = &xpc_dbg_name
70};
71
72struct device *xpc_part = &xpc_part_dbg_subname;
73struct device *xpc_chan = &xpc_chan_dbg_subname;
74
75static int xpc_kdebug_ignore;
76
77/* systune related variables for /proc/sys directories */
78
79static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
80static int xpc_hb_min_interval = 1;
81static int xpc_hb_max_interval = 10;
82
83static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
84static int xpc_hb_check_min_interval = 10;
85static int xpc_hb_check_max_interval = 120;
86
87int xpc_disengage_timelimit = XPC_DISENGAGE_DEFAULT_TIMELIMIT;
88static int xpc_disengage_min_timelimit; /* = 0 */
89static int xpc_disengage_max_timelimit = 120;
90
91static ctl_table xpc_sys_xpc_hb_dir[] = {
92 {
93 .procname = "hb_interval",
94 .data = &xpc_hb_interval,
95 .maxlen = sizeof(int),
96 .mode = 0644,
97 .proc_handler = proc_dointvec_minmax,
98 .extra1 = &xpc_hb_min_interval,
99 .extra2 = &xpc_hb_max_interval},
100 {
101 .procname = "hb_check_interval",
102 .data = &xpc_hb_check_interval,
103 .maxlen = sizeof(int),
104 .mode = 0644,
105 .proc_handler = proc_dointvec_minmax,
106 .extra1 = &xpc_hb_check_min_interval,
107 .extra2 = &xpc_hb_check_max_interval},
108 {}
109};
110static ctl_table xpc_sys_xpc_dir[] = {
111 {
112 .procname = "hb",
113 .mode = 0555,
114 .child = xpc_sys_xpc_hb_dir},
115 {
116 .procname = "disengage_timelimit",
117 .data = &xpc_disengage_timelimit,
118 .maxlen = sizeof(int),
119 .mode = 0644,
120 .proc_handler = proc_dointvec_minmax,
121 .extra1 = &xpc_disengage_min_timelimit,
122 .extra2 = &xpc_disengage_max_timelimit},
123 {}
124};
125static ctl_table xpc_sys_dir[] = {
126 {
127 .procname = "xpc",
128 .mode = 0555,
129 .child = xpc_sys_xpc_dir},
130 {}
131};
132static struct ctl_table_header *xpc_sysctl;
133
134/* non-zero if any remote partition disengage was timed out */
135int xpc_disengage_timedout;
136
137/* #of activate IRQs received and not yet processed */
138int xpc_activate_IRQ_rcvd;
139DEFINE_SPINLOCK(xpc_activate_IRQ_rcvd_lock);
140
141/* IRQ handler notifies this wait queue on receipt of an IRQ */
142DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq);
143
144static unsigned long xpc_hb_check_timeout;
145static struct timer_list xpc_hb_timer;
146
147/* notification that the xpc_hb_checker thread has exited */
148static DECLARE_COMPLETION(xpc_hb_checker_exited);
149
150/* notification that the xpc_discovery thread has exited */
151static DECLARE_COMPLETION(xpc_discovery_exited);
152
153static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
154
155static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
156static struct notifier_block xpc_reboot_notifier = {
157 .notifier_call = xpc_system_reboot,
158};
159
160static int xpc_system_die(struct notifier_block *, unsigned long, void *);
161static struct notifier_block xpc_die_notifier = {
162 .notifier_call = xpc_system_die,
163};
164
165struct xpc_arch_operations xpc_arch_ops;
166
167/*
168 * Timer function to enforce the timelimit on the partition disengage.
169 */
170static void
171xpc_timeout_partition_disengage(unsigned long data)
172{
173 struct xpc_partition *part = (struct xpc_partition *)data;
174
175 DBUG_ON(time_is_after_jiffies(part->disengage_timeout));
176
177 (void)xpc_partition_disengaged(part);
178
179 DBUG_ON(part->disengage_timeout != 0);
180 DBUG_ON(xpc_arch_ops.partition_engaged(XPC_PARTID(part)));
181}
182
183/*
184 * Timer to produce the heartbeat. The timer structures function is
185 * already set when this is initially called. A tunable is used to
186 * specify when the next timeout should occur.
187 */
188static void
189xpc_hb_beater(unsigned long dummy)
190{
191 xpc_arch_ops.increment_heartbeat();
192
193 if (time_is_before_eq_jiffies(xpc_hb_check_timeout))
194 wake_up_interruptible(&xpc_activate_IRQ_wq);
195
196 xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
197 add_timer(&xpc_hb_timer);
198}
199
200static void
201xpc_start_hb_beater(void)
202{
203 xpc_arch_ops.heartbeat_init();
204 init_timer(&xpc_hb_timer);
205 xpc_hb_timer.function = xpc_hb_beater;
206 xpc_hb_beater(0);
207}
208
209static void
210xpc_stop_hb_beater(void)
211{
212 del_timer_sync(&xpc_hb_timer);
213 xpc_arch_ops.heartbeat_exit();
214}
215
216/*
217 * At periodic intervals, scan through all active partitions and ensure
218 * their heartbeat is still active. If not, the partition is deactivated.
219 */
220static void
221xpc_check_remote_hb(void)
222{
223 struct xpc_partition *part;
224 short partid;
225 enum xp_retval ret;
226
227 for (partid = 0; partid < xp_max_npartitions; partid++) {
228
229 if (xpc_exiting)
230 break;
231
232 if (partid == xp_partition_id)
233 continue;
234
235 part = &xpc_partitions[partid];
236
237 if (part->act_state == XPC_P_AS_INACTIVE ||
238 part->act_state == XPC_P_AS_DEACTIVATING) {
239 continue;
240 }
241
242 ret = xpc_arch_ops.get_remote_heartbeat(part);
243 if (ret != xpSuccess)
244 XPC_DEACTIVATE_PARTITION(part, ret);
245 }
246}
247
248/*
249 * This thread is responsible for nearly all of the partition
250 * activation/deactivation.
251 */
252static int
253xpc_hb_checker(void *ignore)
254{
255 int force_IRQ = 0;
256
257 /* this thread was marked active by xpc_hb_init() */
258
259 set_cpus_allowed_ptr(current, cpumask_of(XPC_HB_CHECK_CPU));
260
261 /* set our heartbeating to other partitions into motion */
262 xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
263 xpc_start_hb_beater();
264
265 while (!xpc_exiting) {
266
267 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
268 "been received\n",
269 (int)(xpc_hb_check_timeout - jiffies),
270 xpc_activate_IRQ_rcvd);
271
272 /* checking of remote heartbeats is skewed by IRQ handling */
273 if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) {
274 xpc_hb_check_timeout = jiffies +
275 (xpc_hb_check_interval * HZ);
276
277 dev_dbg(xpc_part, "checking remote heartbeats\n");
278 xpc_check_remote_hb();
279
280 /*
281 * On sn2 we need to periodically recheck to ensure no
282 * IRQ/amo pairs have been missed.
283 */
284 if (is_shub())
285 force_IRQ = 1;
286 }
287
288 /* check for outstanding IRQs */
289 if (xpc_activate_IRQ_rcvd > 0 || force_IRQ != 0) {
290 force_IRQ = 0;
291 dev_dbg(xpc_part, "processing activate IRQs "
292 "received\n");
293 xpc_arch_ops.process_activate_IRQ_rcvd();
294 }
295
296 /* wait for IRQ or timeout */
297 (void)wait_event_interruptible(xpc_activate_IRQ_wq,
298 (time_is_before_eq_jiffies(
299 xpc_hb_check_timeout) ||
300 xpc_activate_IRQ_rcvd > 0 ||
301 xpc_exiting));
302 }
303
304 xpc_stop_hb_beater();
305
306 dev_dbg(xpc_part, "heartbeat checker is exiting\n");
307
308 /* mark this thread as having exited */
309 complete(&xpc_hb_checker_exited);
310 return 0;
311}
312
313/*
314 * This thread will attempt to discover other partitions to activate
315 * based on info provided by SAL. This new thread is short lived and
316 * will exit once discovery is complete.
317 */
318static int
319xpc_initiate_discovery(void *ignore)
320{
321 xpc_discovery();
322
323 dev_dbg(xpc_part, "discovery thread is exiting\n");
324
325 /* mark this thread as having exited */
326 complete(&xpc_discovery_exited);
327 return 0;
328}
329
330/*
331 * The first kthread assigned to a newly activated partition is the one
332 * created by XPC HB with which it calls xpc_activating(). XPC hangs on to
333 * that kthread until the partition is brought down, at which time that kthread
334 * returns back to XPC HB. (The return of that kthread will signify to XPC HB
335 * that XPC has dismantled all communication infrastructure for the associated
336 * partition.) This kthread becomes the channel manager for that partition.
337 *
338 * Each active partition has a channel manager, who, besides connecting and
339 * disconnecting channels, will ensure that each of the partition's connected
340 * channels has the required number of assigned kthreads to get the work done.
341 */
342static void
343xpc_channel_mgr(struct xpc_partition *part)
344{
345 while (part->act_state != XPC_P_AS_DEACTIVATING ||
346 atomic_read(&part->nchannels_active) > 0 ||
347 !xpc_partition_disengaged(part)) {
348
349 xpc_process_sent_chctl_flags(part);
350
351 /*
352 * Wait until we've been requested to activate kthreads or
353 * all of the channel's message queues have been torn down or
354 * a signal is pending.
355 *
356 * The channel_mgr_requests is set to 1 after being awakened,
357 * This is done to prevent the channel mgr from making one pass
358 * through the loop for each request, since he will
359 * be servicing all the requests in one pass. The reason it's
360 * set to 1 instead of 0 is so that other kthreads will know
361 * that the channel mgr is running and won't bother trying to
362 * wake him up.
363 */
364 atomic_dec(&part->channel_mgr_requests);
365 (void)wait_event_interruptible(part->channel_mgr_wq,
366 (atomic_read(&part->channel_mgr_requests) > 0 ||
367 part->chctl.all_flags != 0 ||
368 (part->act_state == XPC_P_AS_DEACTIVATING &&
369 atomic_read(&part->nchannels_active) == 0 &&
370 xpc_partition_disengaged(part))));
371 atomic_set(&part->channel_mgr_requests, 1);
372 }
373}
374
375/*
376 * Guarantee that the kzalloc'd memory is cacheline aligned.
377 */
378void *
379xpc_kzalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
380{
381 /* see if kzalloc will give us cachline aligned memory by default */
382 *base = kzalloc(size, flags);
383 if (*base == NULL)
384 return NULL;
385
386 if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
387 return *base;
388
389 kfree(*base);
390
391 /* nope, we'll have to do it ourselves */
392 *base = kzalloc(size + L1_CACHE_BYTES, flags);
393 if (*base == NULL)
394 return NULL;
395
396 return (void *)L1_CACHE_ALIGN((u64)*base);
397}
398
399/*
400 * Setup the channel structures necessary to support XPartition Communication
401 * between the specified remote partition and the local one.
402 */
403static enum xp_retval
404xpc_setup_ch_structures(struct xpc_partition *part)
405{
406 enum xp_retval ret;
407 int ch_number;
408 struct xpc_channel *ch;
409 short partid = XPC_PARTID(part);
410
411 /*
412 * Allocate all of the channel structures as a contiguous chunk of
413 * memory.
414 */
415 DBUG_ON(part->channels != NULL);
416 part->channels = kzalloc(sizeof(struct xpc_channel) * XPC_MAX_NCHANNELS,
417 GFP_KERNEL);
418 if (part->channels == NULL) {
419 dev_err(xpc_chan, "can't get memory for channels\n");
420 return xpNoMemory;
421 }
422
423 /* allocate the remote open and close args */
424
425 part->remote_openclose_args =
426 xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE,
427 GFP_KERNEL, &part->
428 remote_openclose_args_base);
429 if (part->remote_openclose_args == NULL) {
430 dev_err(xpc_chan, "can't get memory for remote connect args\n");
431 ret = xpNoMemory;
432 goto out_1;
433 }
434
435 part->chctl.all_flags = 0;
436 spin_lock_init(&part->chctl_lock);
437
438 atomic_set(&part->channel_mgr_requests, 1);
439 init_waitqueue_head(&part->channel_mgr_wq);
440
441 part->nchannels = XPC_MAX_NCHANNELS;
442
443 atomic_set(&part->nchannels_active, 0);
444 atomic_set(&part->nchannels_engaged, 0);
445
446 for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
447 ch = &part->channels[ch_number];
448
449 ch->partid = partid;
450 ch->number = ch_number;
451 ch->flags = XPC_C_DISCONNECTED;
452
453 atomic_set(&ch->kthreads_assigned, 0);
454 atomic_set(&ch->kthreads_idle, 0);
455 atomic_set(&ch->kthreads_active, 0);
456
457 atomic_set(&ch->references, 0);
458 atomic_set(&ch->n_to_notify, 0);
459
460 spin_lock_init(&ch->lock);
461 init_completion(&ch->wdisconnect_wait);
462
463 atomic_set(&ch->n_on_msg_allocate_wq, 0);
464 init_waitqueue_head(&ch->msg_allocate_wq);
465 init_waitqueue_head(&ch->idle_wq);
466 }
467
468 ret = xpc_arch_ops.setup_ch_structures(part);
469 if (ret != xpSuccess)
470 goto out_2;
471
472 /*
473 * With the setting of the partition setup_state to XPC_P_SS_SETUP,
474 * we're declaring that this partition is ready to go.
475 */
476 part->setup_state = XPC_P_SS_SETUP;
477
478 return xpSuccess;
479
480 /* setup of ch structures failed */
481out_2:
482 kfree(part->remote_openclose_args_base);
483 part->remote_openclose_args = NULL;
484out_1:
485 kfree(part->channels);
486 part->channels = NULL;
487 return ret;
488}
489
490/*
491 * Teardown the channel structures necessary to support XPartition Communication
492 * between the specified remote partition and the local one.
493 */
494static void
495xpc_teardown_ch_structures(struct xpc_partition *part)
496{
497 DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
498 DBUG_ON(atomic_read(&part->nchannels_active) != 0);
499
500 /*
501 * Make this partition inaccessible to local processes by marking it
502 * as no longer setup. Then wait before proceeding with the teardown
503 * until all existing references cease.
504 */
505 DBUG_ON(part->setup_state != XPC_P_SS_SETUP);
506 part->setup_state = XPC_P_SS_WTEARDOWN;
507
508 wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));
509
510 /* now we can begin tearing down the infrastructure */
511
512 xpc_arch_ops.teardown_ch_structures(part);
513
514 kfree(part->remote_openclose_args_base);
515 part->remote_openclose_args = NULL;
516 kfree(part->channels);
517 part->channels = NULL;
518
519 part->setup_state = XPC_P_SS_TORNDOWN;
520}
521
522/*
523 * When XPC HB determines that a partition has come up, it will create a new
524 * kthread and that kthread will call this function to attempt to set up the
525 * basic infrastructure used for Cross Partition Communication with the newly
526 * upped partition.
527 *
528 * The kthread that was created by XPC HB and which setup the XPC
529 * infrastructure will remain assigned to the partition becoming the channel
530 * manager for that partition until the partition is deactivating, at which
531 * time the kthread will teardown the XPC infrastructure and then exit.
532 */
533static int
534xpc_activating(void *__partid)
535{
536 short partid = (u64)__partid;
537 struct xpc_partition *part = &xpc_partitions[partid];
538 unsigned long irq_flags;
539
540 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
541
542 spin_lock_irqsave(&part->act_lock, irq_flags);
543
544 if (part->act_state == XPC_P_AS_DEACTIVATING) {
545 part->act_state = XPC_P_AS_INACTIVE;
546 spin_unlock_irqrestore(&part->act_lock, irq_flags);
547 part->remote_rp_pa = 0;
548 return 0;
549 }
550
551 /* indicate the thread is activating */
552 DBUG_ON(part->act_state != XPC_P_AS_ACTIVATION_REQ);
553 part->act_state = XPC_P_AS_ACTIVATING;
554
555 XPC_SET_REASON(part, 0, 0);
556 spin_unlock_irqrestore(&part->act_lock, irq_flags);
557
558 dev_dbg(xpc_part, "activating partition %d\n", partid);
559
560 xpc_arch_ops.allow_hb(partid);
561
562 if (xpc_setup_ch_structures(part) == xpSuccess) {
563 (void)xpc_part_ref(part); /* this will always succeed */
564
565 if (xpc_arch_ops.make_first_contact(part) == xpSuccess) {
566 xpc_mark_partition_active(part);
567 xpc_channel_mgr(part);
568 /* won't return until partition is deactivating */
569 }
570
571 xpc_part_deref(part);
572 xpc_teardown_ch_structures(part);
573 }
574
575 xpc_arch_ops.disallow_hb(partid);
576 xpc_mark_partition_inactive(part);
577
578 if (part->reason == xpReactivating) {
579 /* interrupting ourselves results in activating partition */
580 xpc_arch_ops.request_partition_reactivation(part);
581 }
582
583 return 0;
584}
585
586void
587xpc_activate_partition(struct xpc_partition *part)
588{
589 short partid = XPC_PARTID(part);
590 unsigned long irq_flags;
591 struct task_struct *kthread;
592
593 spin_lock_irqsave(&part->act_lock, irq_flags);
594
595 DBUG_ON(part->act_state != XPC_P_AS_INACTIVE);
596
597 part->act_state = XPC_P_AS_ACTIVATION_REQ;
598 XPC_SET_REASON(part, xpCloneKThread, __LINE__);
599
600 spin_unlock_irqrestore(&part->act_lock, irq_flags);
601
602 kthread = kthread_run(xpc_activating, (void *)((u64)partid), "xpc%02d",
603 partid);
604 if (IS_ERR(kthread)) {
605 spin_lock_irqsave(&part->act_lock, irq_flags);
606 part->act_state = XPC_P_AS_INACTIVE;
607 XPC_SET_REASON(part, xpCloneKThreadFailed, __LINE__);
608 spin_unlock_irqrestore(&part->act_lock, irq_flags);
609 }
610}
611
612void
613xpc_activate_kthreads(struct xpc_channel *ch, int needed)
614{
615 int idle = atomic_read(&ch->kthreads_idle);
616 int assigned = atomic_read(&ch->kthreads_assigned);
617 int wakeup;
618
619 DBUG_ON(needed <= 0);
620
621 if (idle > 0) {
622 wakeup = (needed > idle) ? idle : needed;
623 needed -= wakeup;
624
625 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
626 "channel=%d\n", wakeup, ch->partid, ch->number);
627
628 /* only wakeup the requested number of kthreads */
629 wake_up_nr(&ch->idle_wq, wakeup);
630 }
631
632 if (needed <= 0)
633 return;
634
635 if (needed + assigned > ch->kthreads_assigned_limit) {
636 needed = ch->kthreads_assigned_limit - assigned;
637 if (needed <= 0)
638 return;
639 }
640
641 dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
642 needed, ch->partid, ch->number);
643
644 xpc_create_kthreads(ch, needed, 0);
645}
646
647/*
648 * This function is where XPC's kthreads wait for messages to deliver.
649 */
650static void
651xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
652{
653 int (*n_of_deliverable_payloads) (struct xpc_channel *) =
654 xpc_arch_ops.n_of_deliverable_payloads;
655
656 do {
657 /* deliver messages to their intended recipients */
658
659 while (n_of_deliverable_payloads(ch) > 0 &&
660 !(ch->flags & XPC_C_DISCONNECTING)) {
661 xpc_deliver_payload(ch);
662 }
663
664 if (atomic_inc_return(&ch->kthreads_idle) >
665 ch->kthreads_idle_limit) {
666 /* too many idle kthreads on this channel */
667 atomic_dec(&ch->kthreads_idle);
668 break;
669 }
670
671 dev_dbg(xpc_chan, "idle kthread calling "
672 "wait_event_interruptible_exclusive()\n");
673
674 (void)wait_event_interruptible_exclusive(ch->idle_wq,
675 (n_of_deliverable_payloads(ch) > 0 ||
676 (ch->flags & XPC_C_DISCONNECTING)));
677
678 atomic_dec(&ch->kthreads_idle);
679
680 } while (!(ch->flags & XPC_C_DISCONNECTING));
681}
682
683static int
684xpc_kthread_start(void *args)
685{
686 short partid = XPC_UNPACK_ARG1(args);
687 u16 ch_number = XPC_UNPACK_ARG2(args);
688 struct xpc_partition *part = &xpc_partitions[partid];
689 struct xpc_channel *ch;
690 int n_needed;
691 unsigned long irq_flags;
692 int (*n_of_deliverable_payloads) (struct xpc_channel *) =
693 xpc_arch_ops.n_of_deliverable_payloads;
694
695 dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
696 partid, ch_number);
697
698 ch = &part->channels[ch_number];
699
700 if (!(ch->flags & XPC_C_DISCONNECTING)) {
701
702 /* let registerer know that connection has been established */
703
704 spin_lock_irqsave(&ch->lock, irq_flags);
705 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
706 ch->flags |= XPC_C_CONNECTEDCALLOUT;
707 spin_unlock_irqrestore(&ch->lock, irq_flags);
708
709 xpc_connected_callout(ch);
710
711 spin_lock_irqsave(&ch->lock, irq_flags);
712 ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
713 spin_unlock_irqrestore(&ch->lock, irq_flags);
714
715 /*
716 * It is possible that while the callout was being
717 * made that the remote partition sent some messages.
718 * If that is the case, we may need to activate
719 * additional kthreads to help deliver them. We only
720 * need one less than total #of messages to deliver.
721 */
722 n_needed = n_of_deliverable_payloads(ch) - 1;
723 if (n_needed > 0 && !(ch->flags & XPC_C_DISCONNECTING))
724 xpc_activate_kthreads(ch, n_needed);
725
726 } else {
727 spin_unlock_irqrestore(&ch->lock, irq_flags);
728 }
729
730 xpc_kthread_waitmsgs(part, ch);
731 }
732
733 /* let registerer know that connection is disconnecting */
734
735 spin_lock_irqsave(&ch->lock, irq_flags);
736 if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
737 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
738 ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
739 spin_unlock_irqrestore(&ch->lock, irq_flags);
740
741 xpc_disconnect_callout(ch, xpDisconnecting);
742
743 spin_lock_irqsave(&ch->lock, irq_flags);
744 ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
745 }
746 spin_unlock_irqrestore(&ch->lock, irq_flags);
747
748 if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
749 atomic_dec_return(&part->nchannels_engaged) == 0) {
750 xpc_arch_ops.indicate_partition_disengaged(part);
751 }
752
753 xpc_msgqueue_deref(ch);
754
755 dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
756 partid, ch_number);
757
758 xpc_part_deref(part);
759 return 0;
760}
761
762/*
763 * For each partition that XPC has established communications with, there is
764 * a minimum of one kernel thread assigned to perform any operation that
765 * may potentially sleep or block (basically the callouts to the asynchronous
766 * functions registered via xpc_connect()).
767 *
768 * Additional kthreads are created and destroyed by XPC as the workload
769 * demands.
770 *
771 * A kthread is assigned to one of the active channels that exists for a given
772 * partition.
773 */
774void
775xpc_create_kthreads(struct xpc_channel *ch, int needed,
776 int ignore_disconnecting)
777{
778 unsigned long irq_flags;
779 u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
780 struct xpc_partition *part = &xpc_partitions[ch->partid];
781 struct task_struct *kthread;
782 void (*indicate_partition_disengaged) (struct xpc_partition *) =
783 xpc_arch_ops.indicate_partition_disengaged;
784
785 while (needed-- > 0) {
786
787 /*
788 * The following is done on behalf of the newly created
789 * kthread. That kthread is responsible for doing the
790 * counterpart to the following before it exits.
791 */
792 if (ignore_disconnecting) {
793 if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
794 /* kthreads assigned had gone to zero */
795 BUG_ON(!(ch->flags &
796 XPC_C_DISCONNECTINGCALLOUT_MADE));
797 break;
798 }
799
800 } else if (ch->flags & XPC_C_DISCONNECTING) {
801 break;
802
803 } else if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
804 atomic_inc_return(&part->nchannels_engaged) == 1) {
805 xpc_arch_ops.indicate_partition_engaged(part);
806 }
807 (void)xpc_part_ref(part);
808 xpc_msgqueue_ref(ch);
809
810 kthread = kthread_run(xpc_kthread_start, (void *)args,
811 "xpc%02dc%d", ch->partid, ch->number);
812 if (IS_ERR(kthread)) {
813 /* the fork failed */
814
815 /*
816 * NOTE: if (ignore_disconnecting &&
817 * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
818 * then we'll deadlock if all other kthreads assigned
819 * to this channel are blocked in the channel's
820 * registerer, because the only thing that will unblock
821 * them is the xpDisconnecting callout that this
822 * failed kthread_run() would have made.
823 */
824
825 if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
826 atomic_dec_return(&part->nchannels_engaged) == 0) {
827 indicate_partition_disengaged(part);
828 }
829 xpc_msgqueue_deref(ch);
830 xpc_part_deref(part);
831
832 if (atomic_read(&ch->kthreads_assigned) <
833 ch->kthreads_idle_limit) {
834 /*
835 * Flag this as an error only if we have an
836 * insufficient #of kthreads for the channel
837 * to function.
838 */
839 spin_lock_irqsave(&ch->lock, irq_flags);
840 XPC_DISCONNECT_CHANNEL(ch, xpLackOfResources,
841 &irq_flags);
842 spin_unlock_irqrestore(&ch->lock, irq_flags);
843 }
844 break;
845 }
846 }
847}
848
849void
850xpc_disconnect_wait(int ch_number)
851{
852 unsigned long irq_flags;
853 short partid;
854 struct xpc_partition *part;
855 struct xpc_channel *ch;
856 int wakeup_channel_mgr;
857
858 /* now wait for all callouts to the caller's function to cease */
859 for (partid = 0; partid < xp_max_npartitions; partid++) {
860 part = &xpc_partitions[partid];
861
862 if (!xpc_part_ref(part))
863 continue;
864
865 ch = &part->channels[ch_number];
866
867 if (!(ch->flags & XPC_C_WDISCONNECT)) {
868 xpc_part_deref(part);
869 continue;
870 }
871
872 wait_for_completion(&ch->wdisconnect_wait);
873
874 spin_lock_irqsave(&ch->lock, irq_flags);
875 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
876 wakeup_channel_mgr = 0;
877
878 if (ch->delayed_chctl_flags) {
879 if (part->act_state != XPC_P_AS_DEACTIVATING) {
880 spin_lock(&part->chctl_lock);
881 part->chctl.flags[ch->number] |=
882 ch->delayed_chctl_flags;
883 spin_unlock(&part->chctl_lock);
884 wakeup_channel_mgr = 1;
885 }
886 ch->delayed_chctl_flags = 0;
887 }
888
889 ch->flags &= ~XPC_C_WDISCONNECT;
890 spin_unlock_irqrestore(&ch->lock, irq_flags);
891
892 if (wakeup_channel_mgr)
893 xpc_wakeup_channel_mgr(part);
894
895 xpc_part_deref(part);
896 }
897}
898
899static int
900xpc_setup_partitions(void)
901{
902 short partid;
903 struct xpc_partition *part;
904
905 xpc_partitions = kzalloc(sizeof(struct xpc_partition) *
906 xp_max_npartitions, GFP_KERNEL);
907 if (xpc_partitions == NULL) {
908 dev_err(xpc_part, "can't get memory for partition structure\n");
909 return -ENOMEM;
910 }
911
912 /*
913 * The first few fields of each entry of xpc_partitions[] need to
914 * be initialized now so that calls to xpc_connect() and
915 * xpc_disconnect() can be made prior to the activation of any remote
916 * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
917 * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
918 * PARTITION HAS BEEN ACTIVATED.
919 */
920 for (partid = 0; partid < xp_max_npartitions; partid++) {
921 part = &xpc_partitions[partid];
922
923 DBUG_ON((u64)part != L1_CACHE_ALIGN((u64)part));
924
925 part->activate_IRQ_rcvd = 0;
926 spin_lock_init(&part->act_lock);
927 part->act_state = XPC_P_AS_INACTIVE;
928 XPC_SET_REASON(part, 0, 0);
929
930 init_timer(&part->disengage_timer);
931 part->disengage_timer.function =
932 xpc_timeout_partition_disengage;
933 part->disengage_timer.data = (unsigned long)part;
934
935 part->setup_state = XPC_P_SS_UNSET;
936 init_waitqueue_head(&part->teardown_wq);
937 atomic_set(&part->references, 0);
938 }
939
940 return xpc_arch_ops.setup_partitions();
941}
942
943static void
944xpc_teardown_partitions(void)
945{
946 xpc_arch_ops.teardown_partitions();
947 kfree(xpc_partitions);
948}
949
950static void
951xpc_do_exit(enum xp_retval reason)
952{
953 short partid;
954 int active_part_count, printed_waiting_msg = 0;
955 struct xpc_partition *part;
956 unsigned long printmsg_time, disengage_timeout = 0;
957
958 /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
959 DBUG_ON(xpc_exiting == 1);
960
961 /*
962 * Let the heartbeat checker thread and the discovery thread
963 * (if one is running) know that they should exit. Also wake up
964 * the heartbeat checker thread in case it's sleeping.
965 */
966 xpc_exiting = 1;
967 wake_up_interruptible(&xpc_activate_IRQ_wq);
968
969 /* wait for the discovery thread to exit */
970 wait_for_completion(&xpc_discovery_exited);
971
972 /* wait for the heartbeat checker thread to exit */
973 wait_for_completion(&xpc_hb_checker_exited);
974
975 /* sleep for a 1/3 of a second or so */
976 (void)msleep_interruptible(300);
977
978 /* wait for all partitions to become inactive */
979
980 printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
981 xpc_disengage_timedout = 0;
982
983 do {
984 active_part_count = 0;
985
986 for (partid = 0; partid < xp_max_npartitions; partid++) {
987 part = &xpc_partitions[partid];
988
989 if (xpc_partition_disengaged(part) &&
990 part->act_state == XPC_P_AS_INACTIVE) {
991 continue;
992 }
993
994 active_part_count++;
995
996 XPC_DEACTIVATE_PARTITION(part, reason);
997
998 if (part->disengage_timeout > disengage_timeout)
999 disengage_timeout = part->disengage_timeout;
1000 }
1001
1002 if (xpc_arch_ops.any_partition_engaged()) {
1003 if (time_is_before_jiffies(printmsg_time)) {
1004 dev_info(xpc_part, "waiting for remote "
1005 "partitions to deactivate, timeout in "
1006 "%ld seconds\n", (disengage_timeout -
1007 jiffies) / HZ);
1008 printmsg_time = jiffies +
1009 (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
1010 printed_waiting_msg = 1;
1011 }
1012
1013 } else if (active_part_count > 0) {
1014 if (printed_waiting_msg) {
1015 dev_info(xpc_part, "waiting for local partition"
1016 " to deactivate\n");
1017 printed_waiting_msg = 0;
1018 }
1019
1020 } else {
1021 if (!xpc_disengage_timedout) {
1022 dev_info(xpc_part, "all partitions have "
1023 "deactivated\n");
1024 }
1025 break;
1026 }
1027
1028 /* sleep for a 1/3 of a second or so */
1029 (void)msleep_interruptible(300);
1030
1031 } while (1);
1032
1033 DBUG_ON(xpc_arch_ops.any_partition_engaged());
1034
1035 xpc_teardown_rsvd_page();
1036
1037 if (reason == xpUnloading) {
1038 (void)unregister_die_notifier(&xpc_die_notifier);
1039 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1040 }
1041
1042 /* clear the interface to XPC's functions */
1043 xpc_clear_interface();
1044
1045 if (xpc_sysctl)
1046 unregister_sysctl_table(xpc_sysctl);
1047
1048 xpc_teardown_partitions();
1049
1050 if (is_shub())
1051 xpc_exit_sn2();
1052 else if (is_uv())
1053 xpc_exit_uv();
1054}
1055
1056/*
1057 * This function is called when the system is being rebooted.
1058 */
1059static int
1060xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1061{
1062 enum xp_retval reason;
1063
1064 switch (event) {
1065 case SYS_RESTART:
1066 reason = xpSystemReboot;
1067 break;
1068 case SYS_HALT:
1069 reason = xpSystemHalt;
1070 break;
1071 case SYS_POWER_OFF:
1072 reason = xpSystemPoweroff;
1073 break;
1074 default:
1075 reason = xpSystemGoingDown;
1076 }
1077
1078 xpc_do_exit(reason);
1079 return NOTIFY_DONE;
1080}
1081
1082/*
1083 * Notify other partitions to deactivate from us by first disengaging from all
1084 * references to our memory.
1085 */
1086static void
1087xpc_die_deactivate(void)
1088{
1089 struct xpc_partition *part;
1090 short partid;
1091 int any_engaged;
1092 long keep_waiting;
1093 long wait_to_print;
1094
1095 /* keep xpc_hb_checker thread from doing anything (just in case) */
1096 xpc_exiting = 1;
1097
1098 xpc_arch_ops.disallow_all_hbs(); /*indicate we're deactivated */
1099
1100 for (partid = 0; partid < xp_max_npartitions; partid++) {
1101 part = &xpc_partitions[partid];
1102
1103 if (xpc_arch_ops.partition_engaged(partid) ||
1104 part->act_state != XPC_P_AS_INACTIVE) {
1105 xpc_arch_ops.request_partition_deactivation(part);
1106 xpc_arch_ops.indicate_partition_disengaged(part);
1107 }
1108 }
1109
1110 /*
1111 * Though we requested that all other partitions deactivate from us,
1112 * we only wait until they've all disengaged or we've reached the
1113 * defined timelimit.
1114 *
1115 * Given that one iteration through the following while-loop takes
1116 * approximately 200 microseconds, calculate the #of loops to take
1117 * before bailing and the #of loops before printing a waiting message.
1118 */
1119 keep_waiting = xpc_disengage_timelimit * 1000 * 5;
1120 wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5;
1121
1122 while (1) {
1123 any_engaged = xpc_arch_ops.any_partition_engaged();
1124 if (!any_engaged) {
1125 dev_info(xpc_part, "all partitions have deactivated\n");
1126 break;
1127 }
1128
1129 if (!keep_waiting--) {
1130 for (partid = 0; partid < xp_max_npartitions;
1131 partid++) {
1132 if (xpc_arch_ops.partition_engaged(partid)) {
1133 dev_info(xpc_part, "deactivate from "
1134 "remote partition %d timed "
1135 "out\n", partid);
1136 }
1137 }
1138 break;
1139 }
1140
1141 if (!wait_to_print--) {
1142 dev_info(xpc_part, "waiting for remote partitions to "
1143 "deactivate, timeout in %ld seconds\n",
1144 keep_waiting / (1000 * 5));
1145 wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL *
1146 1000 * 5;
1147 }
1148
1149 udelay(200);
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 */
1161static int
1162xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused)
1163{
1164#ifdef CONFIG_IA64 /* !!! temporary kludge */
1165 switch (event) {
1166 case DIE_MACHINE_RESTART:
1167 case DIE_MACHINE_HALT:
1168 xpc_die_deactivate();
1169 break;
1170
1171 case DIE_KDEBUG_ENTER:
1172 /* Should lack of heartbeat be ignored by other partitions? */
1173 if (!xpc_kdebug_ignore)
1174 break;
1175
1176 /* fall through */
1177 case DIE_MCA_MONARCH_ENTER:
1178 case DIE_INIT_MONARCH_ENTER:
1179 xpc_arch_ops.offline_heartbeat();
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_arch_ops.online_heartbeat();
1191 break;
1192 }
1193#else
1194 xpc_die_deactivate();
1195#endif
1196
1197 return NOTIFY_DONE;
1198}
1199
1200int __init
1201xpc_init(void)
1202{
1203 int ret;
1204 struct task_struct *kthread;
1205
1206 dev_set_name(xpc_part, "part");
1207 dev_set_name(xpc_chan, "chan");
1208
1209 if (is_shub()) {
1210 /*
1211 * The ia64-sn2 architecture supports at most 64 partitions.
1212 * And the inability to unregister remote amos restricts us
1213 * further to only support exactly 64 partitions on this
1214 * architecture, no less.
1215 */
1216 if (xp_max_npartitions != 64) {
1217 dev_err(xpc_part, "max #of partitions not set to 64\n");
1218 ret = -EINVAL;
1219 } else {
1220 ret = xpc_init_sn2();
1221 }
1222
1223 } else if (is_uv()) {
1224 ret = xpc_init_uv();
1225
1226 } else {
1227 ret = -ENODEV;
1228 }
1229
1230 if (ret != 0)
1231 return ret;
1232
1233 ret = xpc_setup_partitions();
1234 if (ret != 0) {
1235 dev_err(xpc_part, "can't get memory for partition structure\n");
1236 goto out_1;
1237 }
1238
1239 xpc_sysctl = register_sysctl_table(xpc_sys_dir);
1240
1241 /*
1242 * Fill the partition reserved page with the information needed by
1243 * other partitions to discover we are alive and establish initial
1244 * communications.
1245 */
1246 ret = xpc_setup_rsvd_page();
1247 if (ret != 0) {
1248 dev_err(xpc_part, "can't setup our reserved page\n");
1249 goto out_2;
1250 }
1251
1252 /* add ourselves to the reboot_notifier_list */
1253 ret = register_reboot_notifier(&xpc_reboot_notifier);
1254 if (ret != 0)
1255 dev_warn(xpc_part, "can't register reboot notifier\n");
1256
1257 /* add ourselves to the die_notifier list */
1258 ret = register_die_notifier(&xpc_die_notifier);
1259 if (ret != 0)
1260 dev_warn(xpc_part, "can't register die notifier\n");
1261
1262 /*
1263 * The real work-horse behind xpc. This processes incoming
1264 * interrupts and monitors remote heartbeats.
1265 */
1266 kthread = kthread_run(xpc_hb_checker, NULL, XPC_HB_CHECK_THREAD_NAME);
1267 if (IS_ERR(kthread)) {
1268 dev_err(xpc_part, "failed while forking hb check thread\n");
1269 ret = -EBUSY;
1270 goto out_3;
1271 }
1272
1273 /*
1274 * Startup a thread that will attempt to discover other partitions to
1275 * activate based on info provided by SAL. This new thread is short
1276 * lived and will exit once discovery is complete.
1277 */
1278 kthread = kthread_run(xpc_initiate_discovery, NULL,
1279 XPC_DISCOVERY_THREAD_NAME);
1280 if (IS_ERR(kthread)) {
1281 dev_err(xpc_part, "failed while forking discovery thread\n");
1282
1283 /* mark this new thread as a non-starter */
1284 complete(&xpc_discovery_exited);
1285
1286 xpc_do_exit(xpUnloading);
1287 return -EBUSY;
1288 }
1289
1290 /* set the interface to point at XPC's functions */
1291 xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1292 xpc_initiate_send, xpc_initiate_send_notify,
1293 xpc_initiate_received, xpc_initiate_partid_to_nasids);
1294
1295 return 0;
1296
1297 /* initialization was not successful */
1298out_3:
1299 xpc_teardown_rsvd_page();
1300
1301 (void)unregister_die_notifier(&xpc_die_notifier);
1302 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1303out_2:
1304 if (xpc_sysctl)
1305 unregister_sysctl_table(xpc_sysctl);
1306
1307 xpc_teardown_partitions();
1308out_1:
1309 if (is_shub())
1310 xpc_exit_sn2();
1311 else if (is_uv())
1312 xpc_exit_uv();
1313 return ret;
1314}
1315
1316module_init(xpc_init);
1317
1318void __exit
1319xpc_exit(void)
1320{
1321 xpc_do_exit(xpUnloading);
1322}
1323
1324module_exit(xpc_exit);
1325
1326MODULE_AUTHOR("Silicon Graphics, Inc.");
1327MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1328MODULE_LICENSE("GPL");
1329
1330module_param(xpc_hb_interval, int, 0);
1331MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1332 "heartbeat increments.");
1333
1334module_param(xpc_hb_check_interval, int, 0);
1335MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1336 "heartbeat checks.");
1337
1338module_param(xpc_disengage_timelimit, int, 0);
1339MODULE_PARM_DESC(xpc_disengage_timelimit, "Number of seconds to wait "
1340 "for disengage to complete.");
1341
1342module_param(xpc_kdebug_ignore, int, 0);
1343MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1344 "other partitions when dropping into kdebug.");
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 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
7 * Copyright (c) 2004-2009 Silicon Graphics, Inc. All Rights Reserved.
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 * . Currently on sn2, we have no way to determine which nasid an IRQ
30 * came from. Thus, xpc_send_IRQ_sn2() does a remote amo write
31 * followed by an IPI. The amo indicates where data is to be pulled
32 * from, so after the IPI arrives, the remote partition checks the amo
33 * word. The IPI can actually arrive before the amo however, so other
34 * code must periodically check for this case. Also, remote amo
35 * operations do not reliably time out. Thus we do a remote PIO read
36 * solely to know whether the remote partition is down and whether we
37 * should stop sending IPIs to it. This remote PIO read operation is
38 * set up in a special nofault region so SAL knows to ignore (and
39 * cleanup) any errors due to the remote amo write, PIO read, and/or
40 * PIO write operations.
41 *
42 * If/when new hardware solves this IPI problem, we should abandon
43 * the current approach.
44 *
45 */
46
47#include <linux/module.h>
48#include <linux/slab.h>
49#include <linux/sysctl.h>
50#include <linux/device.h>
51#include <linux/delay.h>
52#include <linux/reboot.h>
53#include <linux/kdebug.h>
54#include <linux/kthread.h>
55#include "xpc.h"
56
57#ifdef CONFIG_X86_64
58#include <asm/traps.h>
59#endif
60
61/* define two XPC debug device structures to be used with dev_dbg() et al */
62
63static struct device_driver xpc_dbg_name = {
64 .name = "xpc"
65};
66
67static struct device xpc_part_dbg_subname = {
68 .init_name = "", /* set to "part" at xpc_init() time */
69 .driver = &xpc_dbg_name
70};
71
72static struct device xpc_chan_dbg_subname = {
73 .init_name = "", /* set to "chan" at xpc_init() time */
74 .driver = &xpc_dbg_name
75};
76
77struct device *xpc_part = &xpc_part_dbg_subname;
78struct device *xpc_chan = &xpc_chan_dbg_subname;
79
80static int xpc_kdebug_ignore;
81
82/* systune related variables for /proc/sys directories */
83
84static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
85static int xpc_hb_min_interval = 1;
86static int xpc_hb_max_interval = 10;
87
88static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL;
89static int xpc_hb_check_min_interval = 10;
90static int xpc_hb_check_max_interval = 120;
91
92int xpc_disengage_timelimit = XPC_DISENGAGE_DEFAULT_TIMELIMIT;
93static int xpc_disengage_min_timelimit; /* = 0 */
94static int xpc_disengage_max_timelimit = 120;
95
96static struct ctl_table xpc_sys_xpc_hb[] = {
97 {
98 .procname = "hb_interval",
99 .data = &xpc_hb_interval,
100 .maxlen = sizeof(int),
101 .mode = 0644,
102 .proc_handler = proc_dointvec_minmax,
103 .extra1 = &xpc_hb_min_interval,
104 .extra2 = &xpc_hb_max_interval},
105 {
106 .procname = "hb_check_interval",
107 .data = &xpc_hb_check_interval,
108 .maxlen = sizeof(int),
109 .mode = 0644,
110 .proc_handler = proc_dointvec_minmax,
111 .extra1 = &xpc_hb_check_min_interval,
112 .extra2 = &xpc_hb_check_max_interval},
113};
114static struct ctl_table xpc_sys_xpc[] = {
115 {
116 .procname = "disengage_timelimit",
117 .data = &xpc_disengage_timelimit,
118 .maxlen = sizeof(int),
119 .mode = 0644,
120 .proc_handler = proc_dointvec_minmax,
121 .extra1 = &xpc_disengage_min_timelimit,
122 .extra2 = &xpc_disengage_max_timelimit},
123};
124
125static struct ctl_table_header *xpc_sysctl;
126static struct ctl_table_header *xpc_sysctl_hb;
127
128/* non-zero if any remote partition disengage was timed out */
129int xpc_disengage_timedout;
130
131/* #of activate IRQs received and not yet processed */
132int xpc_activate_IRQ_rcvd;
133DEFINE_SPINLOCK(xpc_activate_IRQ_rcvd_lock);
134
135/* IRQ handler notifies this wait queue on receipt of an IRQ */
136DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq);
137
138static unsigned long xpc_hb_check_timeout;
139static struct timer_list xpc_hb_timer;
140
141/* notification that the xpc_hb_checker thread has exited */
142static DECLARE_COMPLETION(xpc_hb_checker_exited);
143
144/* notification that the xpc_discovery thread has exited */
145static DECLARE_COMPLETION(xpc_discovery_exited);
146
147static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
148
149static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
150static struct notifier_block xpc_reboot_notifier = {
151 .notifier_call = xpc_system_reboot,
152};
153
154static int xpc_system_die(struct notifier_block *, unsigned long, void *);
155static struct notifier_block xpc_die_notifier = {
156 .notifier_call = xpc_system_die,
157};
158
159struct xpc_arch_operations xpc_arch_ops;
160
161/*
162 * Timer function to enforce the timelimit on the partition disengage.
163 */
164static void
165xpc_timeout_partition_disengage(struct timer_list *t)
166{
167 struct xpc_partition *part = from_timer(part, t, disengage_timer);
168
169 DBUG_ON(time_is_after_jiffies(part->disengage_timeout));
170
171 xpc_partition_disengaged_from_timer(part);
172
173 DBUG_ON(part->disengage_timeout != 0);
174 DBUG_ON(xpc_arch_ops.partition_engaged(XPC_PARTID(part)));
175}
176
177/*
178 * Timer to produce the heartbeat. The timer structures function is
179 * already set when this is initially called. A tunable is used to
180 * specify when the next timeout should occur.
181 */
182static void
183xpc_hb_beater(struct timer_list *unused)
184{
185 xpc_arch_ops.increment_heartbeat();
186
187 if (time_is_before_eq_jiffies(xpc_hb_check_timeout))
188 wake_up_interruptible(&xpc_activate_IRQ_wq);
189
190 xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
191 add_timer(&xpc_hb_timer);
192}
193
194static void
195xpc_start_hb_beater(void)
196{
197 xpc_arch_ops.heartbeat_init();
198 timer_setup(&xpc_hb_timer, xpc_hb_beater, 0);
199 xpc_hb_beater(NULL);
200}
201
202static void
203xpc_stop_hb_beater(void)
204{
205 del_timer_sync(&xpc_hb_timer);
206 xpc_arch_ops.heartbeat_exit();
207}
208
209/*
210 * At periodic intervals, scan through all active partitions and ensure
211 * their heartbeat is still active. If not, the partition is deactivated.
212 */
213static void
214xpc_check_remote_hb(void)
215{
216 struct xpc_partition *part;
217 short partid;
218 enum xp_retval ret;
219
220 for (partid = 0; partid < xp_max_npartitions; partid++) {
221
222 if (xpc_exiting)
223 break;
224
225 if (partid == xp_partition_id)
226 continue;
227
228 part = &xpc_partitions[partid];
229
230 if (part->act_state == XPC_P_AS_INACTIVE ||
231 part->act_state == XPC_P_AS_DEACTIVATING) {
232 continue;
233 }
234
235 ret = xpc_arch_ops.get_remote_heartbeat(part);
236 if (ret != xpSuccess)
237 XPC_DEACTIVATE_PARTITION(part, ret);
238 }
239}
240
241/*
242 * This thread is responsible for nearly all of the partition
243 * activation/deactivation.
244 */
245static int
246xpc_hb_checker(void *ignore)
247{
248 int force_IRQ = 0;
249
250 /* this thread was marked active by xpc_hb_init() */
251
252 set_cpus_allowed_ptr(current, cpumask_of(XPC_HB_CHECK_CPU));
253
254 /* set our heartbeating to other partitions into motion */
255 xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
256 xpc_start_hb_beater();
257
258 while (!xpc_exiting) {
259
260 dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have "
261 "been received\n",
262 (int)(xpc_hb_check_timeout - jiffies),
263 xpc_activate_IRQ_rcvd);
264
265 /* checking of remote heartbeats is skewed by IRQ handling */
266 if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) {
267 xpc_hb_check_timeout = jiffies +
268 (xpc_hb_check_interval * HZ);
269
270 dev_dbg(xpc_part, "checking remote heartbeats\n");
271 xpc_check_remote_hb();
272 }
273
274 /* check for outstanding IRQs */
275 if (xpc_activate_IRQ_rcvd > 0 || force_IRQ != 0) {
276 force_IRQ = 0;
277 dev_dbg(xpc_part, "processing activate IRQs "
278 "received\n");
279 xpc_arch_ops.process_activate_IRQ_rcvd();
280 }
281
282 /* wait for IRQ or timeout */
283 (void)wait_event_interruptible(xpc_activate_IRQ_wq,
284 (time_is_before_eq_jiffies(
285 xpc_hb_check_timeout) ||
286 xpc_activate_IRQ_rcvd > 0 ||
287 xpc_exiting));
288 }
289
290 xpc_stop_hb_beater();
291
292 dev_dbg(xpc_part, "heartbeat checker is exiting\n");
293
294 /* mark this thread as having exited */
295 complete(&xpc_hb_checker_exited);
296 return 0;
297}
298
299/*
300 * This thread will attempt to discover other partitions to activate
301 * based on info provided by SAL. This new thread is short lived and
302 * will exit once discovery is complete.
303 */
304static int
305xpc_initiate_discovery(void *ignore)
306{
307 xpc_discovery();
308
309 dev_dbg(xpc_part, "discovery thread is exiting\n");
310
311 /* mark this thread as having exited */
312 complete(&xpc_discovery_exited);
313 return 0;
314}
315
316/*
317 * The first kthread assigned to a newly activated partition is the one
318 * created by XPC HB with which it calls xpc_activating(). XPC hangs on to
319 * that kthread until the partition is brought down, at which time that kthread
320 * returns back to XPC HB. (The return of that kthread will signify to XPC HB
321 * that XPC has dismantled all communication infrastructure for the associated
322 * partition.) This kthread becomes the channel manager for that partition.
323 *
324 * Each active partition has a channel manager, who, besides connecting and
325 * disconnecting channels, will ensure that each of the partition's connected
326 * channels has the required number of assigned kthreads to get the work done.
327 */
328static void
329xpc_channel_mgr(struct xpc_partition *part)
330{
331 while (part->act_state != XPC_P_AS_DEACTIVATING ||
332 atomic_read(&part->nchannels_active) > 0 ||
333 !xpc_partition_disengaged(part)) {
334
335 xpc_process_sent_chctl_flags(part);
336
337 /*
338 * Wait until we've been requested to activate kthreads or
339 * all of the channel's message queues have been torn down or
340 * a signal is pending.
341 *
342 * The channel_mgr_requests is set to 1 after being awakened,
343 * This is done to prevent the channel mgr from making one pass
344 * through the loop for each request, since he will
345 * be servicing all the requests in one pass. The reason it's
346 * set to 1 instead of 0 is so that other kthreads will know
347 * that the channel mgr is running and won't bother trying to
348 * wake him up.
349 */
350 atomic_dec(&part->channel_mgr_requests);
351 (void)wait_event_interruptible(part->channel_mgr_wq,
352 (atomic_read(&part->channel_mgr_requests) > 0 ||
353 part->chctl.all_flags != 0 ||
354 (part->act_state == XPC_P_AS_DEACTIVATING &&
355 atomic_read(&part->nchannels_active) == 0 &&
356 xpc_partition_disengaged(part))));
357 atomic_set(&part->channel_mgr_requests, 1);
358 }
359}
360
361/*
362 * Guarantee that the kzalloc'd memory is cacheline aligned.
363 */
364void *
365xpc_kzalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
366{
367 /* see if kzalloc will give us cachline aligned memory by default */
368 *base = kzalloc(size, flags);
369 if (*base == NULL)
370 return NULL;
371
372 if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
373 return *base;
374
375 kfree(*base);
376
377 /* nope, we'll have to do it ourselves */
378 *base = kzalloc(size + L1_CACHE_BYTES, flags);
379 if (*base == NULL)
380 return NULL;
381
382 return (void *)L1_CACHE_ALIGN((u64)*base);
383}
384
385/*
386 * Setup the channel structures necessary to support XPartition Communication
387 * between the specified remote partition and the local one.
388 */
389static enum xp_retval
390xpc_setup_ch_structures(struct xpc_partition *part)
391{
392 enum xp_retval ret;
393 int ch_number;
394 struct xpc_channel *ch;
395 short partid = XPC_PARTID(part);
396
397 /*
398 * Allocate all of the channel structures as a contiguous chunk of
399 * memory.
400 */
401 DBUG_ON(part->channels != NULL);
402 part->channels = kcalloc(XPC_MAX_NCHANNELS,
403 sizeof(struct xpc_channel),
404 GFP_KERNEL);
405 if (part->channels == NULL) {
406 dev_err(xpc_chan, "can't get memory for channels\n");
407 return xpNoMemory;
408 }
409
410 /* allocate the remote open and close args */
411
412 part->remote_openclose_args =
413 xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE,
414 GFP_KERNEL, &part->
415 remote_openclose_args_base);
416 if (part->remote_openclose_args == NULL) {
417 dev_err(xpc_chan, "can't get memory for remote connect args\n");
418 ret = xpNoMemory;
419 goto out_1;
420 }
421
422 part->chctl.all_flags = 0;
423 spin_lock_init(&part->chctl_lock);
424
425 atomic_set(&part->channel_mgr_requests, 1);
426 init_waitqueue_head(&part->channel_mgr_wq);
427
428 part->nchannels = XPC_MAX_NCHANNELS;
429
430 atomic_set(&part->nchannels_active, 0);
431 atomic_set(&part->nchannels_engaged, 0);
432
433 for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
434 ch = &part->channels[ch_number];
435
436 ch->partid = partid;
437 ch->number = ch_number;
438 ch->flags = XPC_C_DISCONNECTED;
439
440 atomic_set(&ch->kthreads_assigned, 0);
441 atomic_set(&ch->kthreads_idle, 0);
442 atomic_set(&ch->kthreads_active, 0);
443
444 atomic_set(&ch->references, 0);
445 atomic_set(&ch->n_to_notify, 0);
446
447 spin_lock_init(&ch->lock);
448 init_completion(&ch->wdisconnect_wait);
449
450 atomic_set(&ch->n_on_msg_allocate_wq, 0);
451 init_waitqueue_head(&ch->msg_allocate_wq);
452 init_waitqueue_head(&ch->idle_wq);
453 }
454
455 ret = xpc_arch_ops.setup_ch_structures(part);
456 if (ret != xpSuccess)
457 goto out_2;
458
459 /*
460 * With the setting of the partition setup_state to XPC_P_SS_SETUP,
461 * we're declaring that this partition is ready to go.
462 */
463 part->setup_state = XPC_P_SS_SETUP;
464
465 return xpSuccess;
466
467 /* setup of ch structures failed */
468out_2:
469 kfree(part->remote_openclose_args_base);
470 part->remote_openclose_args = NULL;
471out_1:
472 kfree(part->channels);
473 part->channels = NULL;
474 return ret;
475}
476
477/*
478 * Teardown the channel structures necessary to support XPartition Communication
479 * between the specified remote partition and the local one.
480 */
481static void
482xpc_teardown_ch_structures(struct xpc_partition *part)
483{
484 DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
485 DBUG_ON(atomic_read(&part->nchannels_active) != 0);
486
487 /*
488 * Make this partition inaccessible to local processes by marking it
489 * as no longer setup. Then wait before proceeding with the teardown
490 * until all existing references cease.
491 */
492 DBUG_ON(part->setup_state != XPC_P_SS_SETUP);
493 part->setup_state = XPC_P_SS_WTEARDOWN;
494
495 wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));
496
497 /* now we can begin tearing down the infrastructure */
498
499 xpc_arch_ops.teardown_ch_structures(part);
500
501 kfree(part->remote_openclose_args_base);
502 part->remote_openclose_args = NULL;
503 kfree(part->channels);
504 part->channels = NULL;
505
506 part->setup_state = XPC_P_SS_TORNDOWN;
507}
508
509/*
510 * When XPC HB determines that a partition has come up, it will create a new
511 * kthread and that kthread will call this function to attempt to set up the
512 * basic infrastructure used for Cross Partition Communication with the newly
513 * upped partition.
514 *
515 * The kthread that was created by XPC HB and which setup the XPC
516 * infrastructure will remain assigned to the partition becoming the channel
517 * manager for that partition until the partition is deactivating, at which
518 * time the kthread will teardown the XPC infrastructure and then exit.
519 */
520static int
521xpc_activating(void *__partid)
522{
523 short partid = (u64)__partid;
524 struct xpc_partition *part = &xpc_partitions[partid];
525 unsigned long irq_flags;
526
527 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
528
529 spin_lock_irqsave(&part->act_lock, irq_flags);
530
531 if (part->act_state == XPC_P_AS_DEACTIVATING) {
532 part->act_state = XPC_P_AS_INACTIVE;
533 spin_unlock_irqrestore(&part->act_lock, irq_flags);
534 part->remote_rp_pa = 0;
535 return 0;
536 }
537
538 /* indicate the thread is activating */
539 DBUG_ON(part->act_state != XPC_P_AS_ACTIVATION_REQ);
540 part->act_state = XPC_P_AS_ACTIVATING;
541
542 XPC_SET_REASON(part, 0, 0);
543 spin_unlock_irqrestore(&part->act_lock, irq_flags);
544
545 dev_dbg(xpc_part, "activating partition %d\n", partid);
546
547 xpc_arch_ops.allow_hb(partid);
548
549 if (xpc_setup_ch_structures(part) == xpSuccess) {
550 (void)xpc_part_ref(part); /* this will always succeed */
551
552 if (xpc_arch_ops.make_first_contact(part) == xpSuccess) {
553 xpc_mark_partition_active(part);
554 xpc_channel_mgr(part);
555 /* won't return until partition is deactivating */
556 }
557
558 xpc_part_deref(part);
559 xpc_teardown_ch_structures(part);
560 }
561
562 xpc_arch_ops.disallow_hb(partid);
563 xpc_mark_partition_inactive(part);
564
565 if (part->reason == xpReactivating) {
566 /* interrupting ourselves results in activating partition */
567 xpc_arch_ops.request_partition_reactivation(part);
568 }
569
570 return 0;
571}
572
573void
574xpc_activate_partition(struct xpc_partition *part)
575{
576 short partid = XPC_PARTID(part);
577 unsigned long irq_flags;
578 struct task_struct *kthread;
579
580 spin_lock_irqsave(&part->act_lock, irq_flags);
581
582 DBUG_ON(part->act_state != XPC_P_AS_INACTIVE);
583
584 part->act_state = XPC_P_AS_ACTIVATION_REQ;
585 XPC_SET_REASON(part, xpCloneKThread, __LINE__);
586
587 spin_unlock_irqrestore(&part->act_lock, irq_flags);
588
589 kthread = kthread_run(xpc_activating, (void *)((u64)partid), "xpc%02d",
590 partid);
591 if (IS_ERR(kthread)) {
592 spin_lock_irqsave(&part->act_lock, irq_flags);
593 part->act_state = XPC_P_AS_INACTIVE;
594 XPC_SET_REASON(part, xpCloneKThreadFailed, __LINE__);
595 spin_unlock_irqrestore(&part->act_lock, irq_flags);
596 }
597}
598
599void
600xpc_activate_kthreads(struct xpc_channel *ch, int needed)
601{
602 int idle = atomic_read(&ch->kthreads_idle);
603 int assigned = atomic_read(&ch->kthreads_assigned);
604 int wakeup;
605
606 DBUG_ON(needed <= 0);
607
608 if (idle > 0) {
609 wakeup = (needed > idle) ? idle : needed;
610 needed -= wakeup;
611
612 dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, "
613 "channel=%d\n", wakeup, ch->partid, ch->number);
614
615 /* only wakeup the requested number of kthreads */
616 wake_up_nr(&ch->idle_wq, wakeup);
617 }
618
619 if (needed <= 0)
620 return;
621
622 if (needed + assigned > ch->kthreads_assigned_limit) {
623 needed = ch->kthreads_assigned_limit - assigned;
624 if (needed <= 0)
625 return;
626 }
627
628 dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
629 needed, ch->partid, ch->number);
630
631 xpc_create_kthreads(ch, needed, 0);
632}
633
634/*
635 * This function is where XPC's kthreads wait for messages to deliver.
636 */
637static void
638xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch)
639{
640 int (*n_of_deliverable_payloads) (struct xpc_channel *) =
641 xpc_arch_ops.n_of_deliverable_payloads;
642
643 do {
644 /* deliver messages to their intended recipients */
645
646 while (n_of_deliverable_payloads(ch) > 0 &&
647 !(ch->flags & XPC_C_DISCONNECTING)) {
648 xpc_deliver_payload(ch);
649 }
650
651 if (atomic_inc_return(&ch->kthreads_idle) >
652 ch->kthreads_idle_limit) {
653 /* too many idle kthreads on this channel */
654 atomic_dec(&ch->kthreads_idle);
655 break;
656 }
657
658 dev_dbg(xpc_chan, "idle kthread calling "
659 "wait_event_interruptible_exclusive()\n");
660
661 (void)wait_event_interruptible_exclusive(ch->idle_wq,
662 (n_of_deliverable_payloads(ch) > 0 ||
663 (ch->flags & XPC_C_DISCONNECTING)));
664
665 atomic_dec(&ch->kthreads_idle);
666
667 } while (!(ch->flags & XPC_C_DISCONNECTING));
668}
669
670static int
671xpc_kthread_start(void *args)
672{
673 short partid = XPC_UNPACK_ARG1(args);
674 u16 ch_number = XPC_UNPACK_ARG2(args);
675 struct xpc_partition *part = &xpc_partitions[partid];
676 struct xpc_channel *ch;
677 int n_needed;
678 unsigned long irq_flags;
679 int (*n_of_deliverable_payloads) (struct xpc_channel *) =
680 xpc_arch_ops.n_of_deliverable_payloads;
681
682 dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n",
683 partid, ch_number);
684
685 ch = &part->channels[ch_number];
686
687 if (!(ch->flags & XPC_C_DISCONNECTING)) {
688
689 /* let registerer know that connection has been established */
690
691 spin_lock_irqsave(&ch->lock, irq_flags);
692 if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) {
693 ch->flags |= XPC_C_CONNECTEDCALLOUT;
694 spin_unlock_irqrestore(&ch->lock, irq_flags);
695
696 xpc_connected_callout(ch);
697
698 spin_lock_irqsave(&ch->lock, irq_flags);
699 ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE;
700 spin_unlock_irqrestore(&ch->lock, irq_flags);
701
702 /*
703 * It is possible that while the callout was being
704 * made that the remote partition sent some messages.
705 * If that is the case, we may need to activate
706 * additional kthreads to help deliver them. We only
707 * need one less than total #of messages to deliver.
708 */
709 n_needed = n_of_deliverable_payloads(ch) - 1;
710 if (n_needed > 0 && !(ch->flags & XPC_C_DISCONNECTING))
711 xpc_activate_kthreads(ch, n_needed);
712
713 } else {
714 spin_unlock_irqrestore(&ch->lock, irq_flags);
715 }
716
717 xpc_kthread_waitmsgs(part, ch);
718 }
719
720 /* let registerer know that connection is disconnecting */
721
722 spin_lock_irqsave(&ch->lock, irq_flags);
723 if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
724 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
725 ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
726 spin_unlock_irqrestore(&ch->lock, irq_flags);
727
728 xpc_disconnect_callout(ch, xpDisconnecting);
729
730 spin_lock_irqsave(&ch->lock, irq_flags);
731 ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
732 }
733 spin_unlock_irqrestore(&ch->lock, irq_flags);
734
735 if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
736 atomic_dec_return(&part->nchannels_engaged) == 0) {
737 xpc_arch_ops.indicate_partition_disengaged(part);
738 }
739
740 xpc_msgqueue_deref(ch);
741
742 dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
743 partid, ch_number);
744
745 xpc_part_deref(part);
746 return 0;
747}
748
749/*
750 * For each partition that XPC has established communications with, there is
751 * a minimum of one kernel thread assigned to perform any operation that
752 * may potentially sleep or block (basically the callouts to the asynchronous
753 * functions registered via xpc_connect()).
754 *
755 * Additional kthreads are created and destroyed by XPC as the workload
756 * demands.
757 *
758 * A kthread is assigned to one of the active channels that exists for a given
759 * partition.
760 */
761void
762xpc_create_kthreads(struct xpc_channel *ch, int needed,
763 int ignore_disconnecting)
764{
765 unsigned long irq_flags;
766 u64 args = XPC_PACK_ARGS(ch->partid, ch->number);
767 struct xpc_partition *part = &xpc_partitions[ch->partid];
768 struct task_struct *kthread;
769 void (*indicate_partition_disengaged) (struct xpc_partition *) =
770 xpc_arch_ops.indicate_partition_disengaged;
771
772 while (needed-- > 0) {
773
774 /*
775 * The following is done on behalf of the newly created
776 * kthread. That kthread is responsible for doing the
777 * counterpart to the following before it exits.
778 */
779 if (ignore_disconnecting) {
780 if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
781 /* kthreads assigned had gone to zero */
782 BUG_ON(!(ch->flags &
783 XPC_C_DISCONNECTINGCALLOUT_MADE));
784 break;
785 }
786
787 } else if (ch->flags & XPC_C_DISCONNECTING) {
788 break;
789
790 } else if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
791 atomic_inc_return(&part->nchannels_engaged) == 1) {
792 xpc_arch_ops.indicate_partition_engaged(part);
793 }
794 (void)xpc_part_ref(part);
795 xpc_msgqueue_ref(ch);
796
797 kthread = kthread_run(xpc_kthread_start, (void *)args,
798 "xpc%02dc%d", ch->partid, ch->number);
799 if (IS_ERR(kthread)) {
800 /* the fork failed */
801
802 /*
803 * NOTE: if (ignore_disconnecting &&
804 * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
805 * then we'll deadlock if all other kthreads assigned
806 * to this channel are blocked in the channel's
807 * registerer, because the only thing that will unblock
808 * them is the xpDisconnecting callout that this
809 * failed kthread_run() would have made.
810 */
811
812 if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
813 atomic_dec_return(&part->nchannels_engaged) == 0) {
814 indicate_partition_disengaged(part);
815 }
816 xpc_msgqueue_deref(ch);
817 xpc_part_deref(part);
818
819 if (atomic_read(&ch->kthreads_assigned) <
820 ch->kthreads_idle_limit) {
821 /*
822 * Flag this as an error only if we have an
823 * insufficient #of kthreads for the channel
824 * to function.
825 */
826 spin_lock_irqsave(&ch->lock, irq_flags);
827 XPC_DISCONNECT_CHANNEL(ch, xpLackOfResources,
828 &irq_flags);
829 spin_unlock_irqrestore(&ch->lock, irq_flags);
830 }
831 break;
832 }
833 }
834}
835
836void
837xpc_disconnect_wait(int ch_number)
838{
839 unsigned long irq_flags;
840 short partid;
841 struct xpc_partition *part;
842 struct xpc_channel *ch;
843 int wakeup_channel_mgr;
844
845 /* now wait for all callouts to the caller's function to cease */
846 for (partid = 0; partid < xp_max_npartitions; partid++) {
847 part = &xpc_partitions[partid];
848
849 if (!xpc_part_ref(part))
850 continue;
851
852 ch = &part->channels[ch_number];
853
854 if (!(ch->flags & XPC_C_WDISCONNECT)) {
855 xpc_part_deref(part);
856 continue;
857 }
858
859 wait_for_completion(&ch->wdisconnect_wait);
860
861 spin_lock_irqsave(&ch->lock, irq_flags);
862 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
863 wakeup_channel_mgr = 0;
864
865 if (ch->delayed_chctl_flags) {
866 if (part->act_state != XPC_P_AS_DEACTIVATING) {
867 spin_lock(&part->chctl_lock);
868 part->chctl.flags[ch->number] |=
869 ch->delayed_chctl_flags;
870 spin_unlock(&part->chctl_lock);
871 wakeup_channel_mgr = 1;
872 }
873 ch->delayed_chctl_flags = 0;
874 }
875
876 ch->flags &= ~XPC_C_WDISCONNECT;
877 spin_unlock_irqrestore(&ch->lock, irq_flags);
878
879 if (wakeup_channel_mgr)
880 xpc_wakeup_channel_mgr(part);
881
882 xpc_part_deref(part);
883 }
884}
885
886static int
887xpc_setup_partitions(void)
888{
889 short partid;
890 struct xpc_partition *part;
891
892 xpc_partitions = kcalloc(xp_max_npartitions,
893 sizeof(struct xpc_partition),
894 GFP_KERNEL);
895 if (xpc_partitions == NULL) {
896 dev_err(xpc_part, "can't get memory for partition structure\n");
897 return -ENOMEM;
898 }
899
900 /*
901 * The first few fields of each entry of xpc_partitions[] need to
902 * be initialized now so that calls to xpc_connect() and
903 * xpc_disconnect() can be made prior to the activation of any remote
904 * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
905 * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
906 * PARTITION HAS BEEN ACTIVATED.
907 */
908 for (partid = 0; partid < xp_max_npartitions; partid++) {
909 part = &xpc_partitions[partid];
910
911 DBUG_ON((u64)part != L1_CACHE_ALIGN((u64)part));
912
913 part->activate_IRQ_rcvd = 0;
914 spin_lock_init(&part->act_lock);
915 part->act_state = XPC_P_AS_INACTIVE;
916 XPC_SET_REASON(part, 0, 0);
917
918 timer_setup(&part->disengage_timer,
919 xpc_timeout_partition_disengage, 0);
920
921 part->setup_state = XPC_P_SS_UNSET;
922 init_waitqueue_head(&part->teardown_wq);
923 atomic_set(&part->references, 0);
924 }
925
926 return xpc_arch_ops.setup_partitions();
927}
928
929static void
930xpc_teardown_partitions(void)
931{
932 xpc_arch_ops.teardown_partitions();
933 kfree(xpc_partitions);
934}
935
936static void
937xpc_do_exit(enum xp_retval reason)
938{
939 short partid;
940 int active_part_count, printed_waiting_msg = 0;
941 struct xpc_partition *part;
942 unsigned long printmsg_time, disengage_timeout = 0;
943
944 /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
945 DBUG_ON(xpc_exiting == 1);
946
947 /*
948 * Let the heartbeat checker thread and the discovery thread
949 * (if one is running) know that they should exit. Also wake up
950 * the heartbeat checker thread in case it's sleeping.
951 */
952 xpc_exiting = 1;
953 wake_up_interruptible(&xpc_activate_IRQ_wq);
954
955 /* wait for the discovery thread to exit */
956 wait_for_completion(&xpc_discovery_exited);
957
958 /* wait for the heartbeat checker thread to exit */
959 wait_for_completion(&xpc_hb_checker_exited);
960
961 /* sleep for a 1/3 of a second or so */
962 (void)msleep_interruptible(300);
963
964 /* wait for all partitions to become inactive */
965
966 printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
967 xpc_disengage_timedout = 0;
968
969 do {
970 active_part_count = 0;
971
972 for (partid = 0; partid < xp_max_npartitions; partid++) {
973 part = &xpc_partitions[partid];
974
975 if (xpc_partition_disengaged(part) &&
976 part->act_state == XPC_P_AS_INACTIVE) {
977 continue;
978 }
979
980 active_part_count++;
981
982 XPC_DEACTIVATE_PARTITION(part, reason);
983
984 if (part->disengage_timeout > disengage_timeout)
985 disengage_timeout = part->disengage_timeout;
986 }
987
988 if (xpc_arch_ops.any_partition_engaged()) {
989 if (time_is_before_jiffies(printmsg_time)) {
990 dev_info(xpc_part, "waiting for remote "
991 "partitions to deactivate, timeout in "
992 "%ld seconds\n", (disengage_timeout -
993 jiffies) / HZ);
994 printmsg_time = jiffies +
995 (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ);
996 printed_waiting_msg = 1;
997 }
998
999 } else if (active_part_count > 0) {
1000 if (printed_waiting_msg) {
1001 dev_info(xpc_part, "waiting for local partition"
1002 " to deactivate\n");
1003 printed_waiting_msg = 0;
1004 }
1005
1006 } else {
1007 if (!xpc_disengage_timedout) {
1008 dev_info(xpc_part, "all partitions have "
1009 "deactivated\n");
1010 }
1011 break;
1012 }
1013
1014 /* sleep for a 1/3 of a second or so */
1015 (void)msleep_interruptible(300);
1016
1017 } while (1);
1018
1019 DBUG_ON(xpc_arch_ops.any_partition_engaged());
1020
1021 xpc_teardown_rsvd_page();
1022
1023 if (reason == xpUnloading) {
1024 (void)unregister_die_notifier(&xpc_die_notifier);
1025 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1026 }
1027
1028 /* clear the interface to XPC's functions */
1029 xpc_clear_interface();
1030
1031 if (xpc_sysctl)
1032 unregister_sysctl_table(xpc_sysctl);
1033 if (xpc_sysctl_hb)
1034 unregister_sysctl_table(xpc_sysctl_hb);
1035
1036 xpc_teardown_partitions();
1037
1038 if (is_uv_system())
1039 xpc_exit_uv();
1040}
1041
1042/*
1043 * This function is called when the system is being rebooted.
1044 */
1045static int
1046xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused)
1047{
1048 enum xp_retval reason;
1049
1050 switch (event) {
1051 case SYS_RESTART:
1052 reason = xpSystemReboot;
1053 break;
1054 case SYS_HALT:
1055 reason = xpSystemHalt;
1056 break;
1057 case SYS_POWER_OFF:
1058 reason = xpSystemPoweroff;
1059 break;
1060 default:
1061 reason = xpSystemGoingDown;
1062 }
1063
1064 xpc_do_exit(reason);
1065 return NOTIFY_DONE;
1066}
1067
1068/* Used to only allow one cpu to complete disconnect */
1069static unsigned int xpc_die_disconnecting;
1070
1071/*
1072 * Notify other partitions to deactivate from us by first disengaging from all
1073 * references to our memory.
1074 */
1075static void
1076xpc_die_deactivate(void)
1077{
1078 struct xpc_partition *part;
1079 short partid;
1080 int any_engaged;
1081 long keep_waiting;
1082 long wait_to_print;
1083
1084 if (cmpxchg(&xpc_die_disconnecting, 0, 1))
1085 return;
1086
1087 /* keep xpc_hb_checker thread from doing anything (just in case) */
1088 xpc_exiting = 1;
1089
1090 xpc_arch_ops.disallow_all_hbs(); /*indicate we're deactivated */
1091
1092 for (partid = 0; partid < xp_max_npartitions; partid++) {
1093 part = &xpc_partitions[partid];
1094
1095 if (xpc_arch_ops.partition_engaged(partid) ||
1096 part->act_state != XPC_P_AS_INACTIVE) {
1097 xpc_arch_ops.request_partition_deactivation(part);
1098 xpc_arch_ops.indicate_partition_disengaged(part);
1099 }
1100 }
1101
1102 /*
1103 * Though we requested that all other partitions deactivate from us,
1104 * we only wait until they've all disengaged or we've reached the
1105 * defined timelimit.
1106 *
1107 * Given that one iteration through the following while-loop takes
1108 * approximately 200 microseconds, calculate the #of loops to take
1109 * before bailing and the #of loops before printing a waiting message.
1110 */
1111 keep_waiting = xpc_disengage_timelimit * 1000 * 5;
1112 wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5;
1113
1114 while (1) {
1115 any_engaged = xpc_arch_ops.any_partition_engaged();
1116 if (!any_engaged) {
1117 dev_info(xpc_part, "all partitions have deactivated\n");
1118 break;
1119 }
1120
1121 if (!keep_waiting--) {
1122 for (partid = 0; partid < xp_max_npartitions;
1123 partid++) {
1124 if (xpc_arch_ops.partition_engaged(partid)) {
1125 dev_info(xpc_part, "deactivate from "
1126 "remote partition %d timed "
1127 "out\n", partid);
1128 }
1129 }
1130 break;
1131 }
1132
1133 if (!wait_to_print--) {
1134 dev_info(xpc_part, "waiting for remote partitions to "
1135 "deactivate, timeout in %ld seconds\n",
1136 keep_waiting / (1000 * 5));
1137 wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL *
1138 1000 * 5;
1139 }
1140
1141 udelay(200);
1142 }
1143}
1144
1145/*
1146 * This function is called when the system is being restarted or halted due
1147 * to some sort of system failure. If this is the case we need to notify the
1148 * other partitions to disengage from all references to our memory.
1149 * This function can also be called when our heartbeater could be offlined
1150 * for a time. In this case we need to notify other partitions to not worry
1151 * about the lack of a heartbeat.
1152 */
1153static int
1154xpc_system_die(struct notifier_block *nb, unsigned long event, void *_die_args)
1155{
1156 struct die_args *die_args = _die_args;
1157
1158 switch (event) {
1159 case DIE_TRAP:
1160 if (die_args->trapnr == X86_TRAP_DF)
1161 xpc_die_deactivate();
1162
1163 if (((die_args->trapnr == X86_TRAP_MF) ||
1164 (die_args->trapnr == X86_TRAP_XF)) &&
1165 !user_mode(die_args->regs))
1166 xpc_die_deactivate();
1167
1168 break;
1169 case DIE_INT3:
1170 case DIE_DEBUG:
1171 break;
1172 case DIE_OOPS:
1173 case DIE_GPF:
1174 default:
1175 xpc_die_deactivate();
1176 }
1177
1178 return NOTIFY_DONE;
1179}
1180
1181static int __init
1182xpc_init(void)
1183{
1184 int ret;
1185 struct task_struct *kthread;
1186
1187 dev_set_name(xpc_part, "part");
1188 dev_set_name(xpc_chan, "chan");
1189
1190 if (is_uv_system()) {
1191 ret = xpc_init_uv();
1192
1193 } else {
1194 ret = -ENODEV;
1195 }
1196
1197 if (ret != 0)
1198 return ret;
1199
1200 ret = xpc_setup_partitions();
1201 if (ret != 0) {
1202 dev_err(xpc_part, "can't get memory for partition structure\n");
1203 goto out_1;
1204 }
1205
1206 xpc_sysctl = register_sysctl("xpc", xpc_sys_xpc);
1207 xpc_sysctl_hb = register_sysctl("xpc/hb", xpc_sys_xpc_hb);
1208
1209 /*
1210 * Fill the partition reserved page with the information needed by
1211 * other partitions to discover we are alive and establish initial
1212 * communications.
1213 */
1214 ret = xpc_setup_rsvd_page();
1215 if (ret != 0) {
1216 dev_err(xpc_part, "can't setup our reserved page\n");
1217 goto out_2;
1218 }
1219
1220 /* add ourselves to the reboot_notifier_list */
1221 ret = register_reboot_notifier(&xpc_reboot_notifier);
1222 if (ret != 0)
1223 dev_warn(xpc_part, "can't register reboot notifier\n");
1224
1225 /* add ourselves to the die_notifier list */
1226 ret = register_die_notifier(&xpc_die_notifier);
1227 if (ret != 0)
1228 dev_warn(xpc_part, "can't register die notifier\n");
1229
1230 /*
1231 * The real work-horse behind xpc. This processes incoming
1232 * interrupts and monitors remote heartbeats.
1233 */
1234 kthread = kthread_run(xpc_hb_checker, NULL, XPC_HB_CHECK_THREAD_NAME);
1235 if (IS_ERR(kthread)) {
1236 dev_err(xpc_part, "failed while forking hb check thread\n");
1237 ret = -EBUSY;
1238 goto out_3;
1239 }
1240
1241 /*
1242 * Startup a thread that will attempt to discover other partitions to
1243 * activate based on info provided by SAL. This new thread is short
1244 * lived and will exit once discovery is complete.
1245 */
1246 kthread = kthread_run(xpc_initiate_discovery, NULL,
1247 XPC_DISCOVERY_THREAD_NAME);
1248 if (IS_ERR(kthread)) {
1249 dev_err(xpc_part, "failed while forking discovery thread\n");
1250
1251 /* mark this new thread as a non-starter */
1252 complete(&xpc_discovery_exited);
1253
1254 xpc_do_exit(xpUnloading);
1255 return -EBUSY;
1256 }
1257
1258 /* set the interface to point at XPC's functions */
1259 xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect,
1260 xpc_initiate_send, xpc_initiate_send_notify,
1261 xpc_initiate_received, xpc_initiate_partid_to_nasids);
1262
1263 return 0;
1264
1265 /* initialization was not successful */
1266out_3:
1267 xpc_teardown_rsvd_page();
1268
1269 (void)unregister_die_notifier(&xpc_die_notifier);
1270 (void)unregister_reboot_notifier(&xpc_reboot_notifier);
1271out_2:
1272 if (xpc_sysctl_hb)
1273 unregister_sysctl_table(xpc_sysctl_hb);
1274 if (xpc_sysctl)
1275 unregister_sysctl_table(xpc_sysctl);
1276
1277 xpc_teardown_partitions();
1278out_1:
1279 if (is_uv_system())
1280 xpc_exit_uv();
1281 return ret;
1282}
1283
1284module_init(xpc_init);
1285
1286static void __exit
1287xpc_exit(void)
1288{
1289 xpc_do_exit(xpUnloading);
1290}
1291
1292module_exit(xpc_exit);
1293
1294MODULE_AUTHOR("Silicon Graphics, Inc.");
1295MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1296MODULE_LICENSE("GPL");
1297
1298module_param(xpc_hb_interval, int, 0);
1299MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between "
1300 "heartbeat increments.");
1301
1302module_param(xpc_hb_check_interval, int, 0);
1303MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between "
1304 "heartbeat checks.");
1305
1306module_param(xpc_disengage_timelimit, int, 0);
1307MODULE_PARM_DESC(xpc_disengage_timelimit, "Number of seconds to wait "
1308 "for disengage to complete.");
1309
1310module_param(xpc_kdebug_ignore, int, 0);
1311MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by "
1312 "other partitions when dropping into kdebug.");