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/kernel.h>
47 #include <linux/module.h>
48 #include <linux/init.h>
49 #include <linux/cache.h>
50 #include <linux/interrupt.h>
51 #include <linux/delay.h>
52 #include <linux/reboot.h>
53 #include <linux/completion.h>
54 #include <linux/kdebug.h>
55 #include <linux/kthread.h>
56 #include <linux/uaccess.h>
57 #include <asm/sn/intr.h>
58 #include <asm/sn/sn_sal.h>
61 /* define two XPC debug device structures to be used with dev_dbg() et al */
63 struct device_driver xpc_dbg_name
= {
67 struct device xpc_part_dbg_subname
= {
68 .bus_id
= {0}, /* set to "part" at xpc_init() time */
69 .driver
= &xpc_dbg_name
72 struct device xpc_chan_dbg_subname
= {
73 .bus_id
= {0}, /* set to "chan" at xpc_init() time */
74 .driver
= &xpc_dbg_name
77 struct device
*xpc_part
= &xpc_part_dbg_subname
;
78 struct device
*xpc_chan
= &xpc_chan_dbg_subname
;
80 static int xpc_kdebug_ignore
;
82 /* systune related variables for /proc/sys directories */
84 static int xpc_hb_interval
= XPC_HB_DEFAULT_INTERVAL
;
85 static int xpc_hb_min_interval
= 1;
86 static int xpc_hb_max_interval
= 10;
88 static int xpc_hb_check_interval
= XPC_HB_CHECK_DEFAULT_INTERVAL
;
89 static int xpc_hb_check_min_interval
= 10;
90 static int xpc_hb_check_max_interval
= 120;
92 int xpc_disengage_timelimit
= XPC_DISENGAGE_DEFAULT_TIMELIMIT
;
93 static int xpc_disengage_min_timelimit
; /* = 0 */
94 static int xpc_disengage_max_timelimit
= 120;
96 static ctl_table xpc_sys_xpc_hb_dir
[] = {
98 .ctl_name
= CTL_UNNUMBERED
,
99 .procname
= "hb_interval",
100 .data
= &xpc_hb_interval
,
101 .maxlen
= sizeof(int),
103 .proc_handler
= &proc_dointvec_minmax
,
104 .strategy
= &sysctl_intvec
,
105 .extra1
= &xpc_hb_min_interval
,
106 .extra2
= &xpc_hb_max_interval
},
108 .ctl_name
= CTL_UNNUMBERED
,
109 .procname
= "hb_check_interval",
110 .data
= &xpc_hb_check_interval
,
111 .maxlen
= sizeof(int),
113 .proc_handler
= &proc_dointvec_minmax
,
114 .strategy
= &sysctl_intvec
,
115 .extra1
= &xpc_hb_check_min_interval
,
116 .extra2
= &xpc_hb_check_max_interval
},
119 static ctl_table xpc_sys_xpc_dir
[] = {
121 .ctl_name
= CTL_UNNUMBERED
,
124 .child
= xpc_sys_xpc_hb_dir
},
126 .ctl_name
= CTL_UNNUMBERED
,
127 .procname
= "disengage_timelimit",
128 .data
= &xpc_disengage_timelimit
,
129 .maxlen
= sizeof(int),
131 .proc_handler
= &proc_dointvec_minmax
,
132 .strategy
= &sysctl_intvec
,
133 .extra1
= &xpc_disengage_min_timelimit
,
134 .extra2
= &xpc_disengage_max_timelimit
},
137 static ctl_table xpc_sys_dir
[] = {
139 .ctl_name
= CTL_UNNUMBERED
,
142 .child
= xpc_sys_xpc_dir
},
145 static struct ctl_table_header
*xpc_sysctl
;
147 /* non-zero if any remote partition disengage was timed out */
148 int xpc_disengage_timedout
;
150 /* #of activate IRQs received */
151 atomic_t xpc_activate_IRQ_rcvd
= ATOMIC_INIT(0);
153 /* IRQ handler notifies this wait queue on receipt of an IRQ */
154 DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq
);
156 static unsigned long xpc_hb_check_timeout
;
157 static struct timer_list xpc_hb_timer
;
158 void *xpc_heartbeating_to_mask
;
160 /* notification that the xpc_hb_checker thread has exited */
161 static DECLARE_COMPLETION(xpc_hb_checker_exited
);
163 /* notification that the xpc_discovery thread has exited */
164 static DECLARE_COMPLETION(xpc_discovery_exited
);
166 static void xpc_kthread_waitmsgs(struct xpc_partition
*, struct xpc_channel
*);
168 static int xpc_system_reboot(struct notifier_block
*, unsigned long, void *);
169 static struct notifier_block xpc_reboot_notifier
= {
170 .notifier_call
= xpc_system_reboot
,
173 static int xpc_system_die(struct notifier_block
*, unsigned long, void *);
174 static struct notifier_block xpc_die_notifier
= {
175 .notifier_call
= xpc_system_die
,
178 enum xp_retval (*xpc_rsvd_page_init
) (struct xpc_rsvd_page
*rp
);
179 void (*xpc_heartbeat_init
) (void);
180 void (*xpc_heartbeat_exit
) (void);
181 void (*xpc_increment_heartbeat
) (void);
182 void (*xpc_offline_heartbeat
) (void);
183 void (*xpc_online_heartbeat
) (void);
184 void (*xpc_check_remote_hb
) (void);
186 enum xp_retval (*xpc_make_first_contact
) (struct xpc_partition
*part
);
187 void (*xpc_notify_senders_of_disconnect
) (struct xpc_channel
*ch
);
188 u64 (*xpc_get_chctl_all_flags
) (struct xpc_partition
*part
);
189 void (*xpc_process_msg_chctl_flags
) (struct xpc_partition
*part
, int ch_number
);
190 int (*xpc_n_of_deliverable_msgs
) (struct xpc_channel
*ch
);
191 struct xpc_msg
*(*xpc_get_deliverable_msg
) (struct xpc_channel
*ch
);
193 void (*xpc_request_partition_activation
) (struct xpc_rsvd_page
*remote_rp
,
194 u64 remote_rp_pa
, int nasid
);
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 * This thread is responsible for nearly all of the partition
274 * activation/deactivation.
277 xpc_hb_checker(void *ignore
)
279 int last_IRQ_count
= 0;
283 /* this thread was marked active by xpc_hb_init() */
285 set_cpus_allowed_ptr(current
, &cpumask_of_cpu(XPC_HB_CHECK_CPU
));
287 /* set our heartbeating to other partitions into motion */
288 xpc_hb_check_timeout
= jiffies
+ (xpc_hb_check_interval
* HZ
);
289 xpc_start_hb_beater();
291 while (!xpc_exiting
) {
293 dev_dbg(xpc_part
, "woke up with %d ticks rem; %d IRQs have "
295 (int)(xpc_hb_check_timeout
- jiffies
),
296 atomic_read(&xpc_activate_IRQ_rcvd
) - last_IRQ_count
);
298 /* checking of remote heartbeats is skewed by IRQ handling */
299 if (time_is_before_eq_jiffies(xpc_hb_check_timeout
)) {
300 dev_dbg(xpc_part
, "checking remote heartbeats\n");
301 xpc_check_remote_hb();
304 * We need to periodically recheck to ensure no
305 * IRQ/amo pairs have been missed. That check
306 * must always reset xpc_hb_check_timeout.
311 /* check for outstanding IRQs */
312 new_IRQ_count
= atomic_read(&xpc_activate_IRQ_rcvd
);
313 if (last_IRQ_count
< new_IRQ_count
|| force_IRQ
!= 0) {
316 dev_dbg(xpc_part
, "found an IRQ to process; will be "
317 "resetting xpc_hb_check_timeout\n");
319 xpc_process_activate_IRQ_rcvd(new_IRQ_count
-
321 last_IRQ_count
= new_IRQ_count
;
323 xpc_hb_check_timeout
= jiffies
+
324 (xpc_hb_check_interval
* HZ
);
327 /* wait for IRQ or timeout */
328 (void)wait_event_interruptible(xpc_activate_IRQ_wq
,
329 (last_IRQ_count
< atomic_read(
330 &xpc_activate_IRQ_rcvd
)
331 || time_is_before_eq_jiffies(
332 xpc_hb_check_timeout
) ||
336 xpc_stop_hb_beater();
338 dev_dbg(xpc_part
, "heartbeat checker is exiting\n");
340 /* mark this thread as having exited */
341 complete(&xpc_hb_checker_exited
);
346 * This thread will attempt to discover other partitions to activate
347 * based on info provided by SAL. This new thread is short lived and
348 * will exit once discovery is complete.
351 xpc_initiate_discovery(void *ignore
)
355 dev_dbg(xpc_part
, "discovery thread is exiting\n");
357 /* mark this thread as having exited */
358 complete(&xpc_discovery_exited
);
363 * The first kthread assigned to a newly activated partition is the one
364 * created by XPC HB with which it calls xpc_activating(). XPC hangs on to
365 * that kthread until the partition is brought down, at which time that kthread
366 * returns back to XPC HB. (The return of that kthread will signify to XPC HB
367 * that XPC has dismantled all communication infrastructure for the associated
368 * partition.) This kthread becomes the channel manager for that partition.
370 * Each active partition has a channel manager, who, besides connecting and
371 * disconnecting channels, will ensure that each of the partition's connected
372 * channels has the required number of assigned kthreads to get the work done.
375 xpc_channel_mgr(struct xpc_partition
*part
)
377 while (part
->act_state
!= XPC_P_DEACTIVATING
||
378 atomic_read(&part
->nchannels_active
) > 0 ||
379 !xpc_partition_disengaged(part
)) {
381 xpc_process_sent_chctl_flags(part
);
384 * Wait until we've been requested to activate kthreads or
385 * all of the channel's message queues have been torn down or
386 * a signal is pending.
388 * The channel_mgr_requests is set to 1 after being awakened,
389 * This is done to prevent the channel mgr from making one pass
390 * through the loop for each request, since he will
391 * be servicing all the requests in one pass. The reason it's
392 * set to 1 instead of 0 is so that other kthreads will know
393 * that the channel mgr is running and won't bother trying to
396 atomic_dec(&part
->channel_mgr_requests
);
397 (void)wait_event_interruptible(part
->channel_mgr_wq
,
398 (atomic_read(&part
->channel_mgr_requests
) > 0 ||
399 part
->chctl
.all_flags
!= 0 ||
400 (part
->act_state
== XPC_P_DEACTIVATING
&&
401 atomic_read(&part
->nchannels_active
) == 0 &&
402 xpc_partition_disengaged(part
))));
403 atomic_set(&part
->channel_mgr_requests
, 1);
408 * When XPC HB determines that a partition has come up, it will create a new
409 * kthread and that kthread will call this function to attempt to set up the
410 * basic infrastructure used for Cross Partition Communication with the newly
413 * The kthread that was created by XPC HB and which setup the XPC
414 * infrastructure will remain assigned to the partition becoming the channel
415 * manager for that partition until the partition is deactivating, at which
416 * time the kthread will teardown the XPC infrastructure and then exit.
419 xpc_activating(void *__partid
)
421 short partid
= (u64
)__partid
;
422 struct xpc_partition
*part
= &xpc_partitions
[partid
];
423 unsigned long irq_flags
;
425 DBUG_ON(partid
< 0 || partid
>= xp_max_npartitions
);
427 spin_lock_irqsave(&part
->act_lock
, irq_flags
);
429 if (part
->act_state
== XPC_P_DEACTIVATING
) {
430 part
->act_state
= XPC_P_INACTIVE
;
431 spin_unlock_irqrestore(&part
->act_lock
, irq_flags
);
432 part
->remote_rp_pa
= 0;
436 /* indicate the thread is activating */
437 DBUG_ON(part
->act_state
!= XPC_P_ACTIVATION_REQ
);
438 part
->act_state
= XPC_P_ACTIVATING
;
440 XPC_SET_REASON(part
, 0, 0);
441 spin_unlock_irqrestore(&part
->act_lock
, irq_flags
);
443 dev_dbg(xpc_part
, "activating partition %d\n", partid
);
445 xpc_allow_hb(partid
);
447 if (xpc_setup_infrastructure(part
) == xpSuccess
) {
448 (void)xpc_part_ref(part
); /* this will always succeed */
450 if (xpc_make_first_contact(part
) == xpSuccess
) {
451 xpc_mark_partition_active(part
);
452 xpc_channel_mgr(part
);
453 /* won't return until partition is deactivating */
456 xpc_part_deref(part
);
457 xpc_teardown_infrastructure(part
);
460 xpc_disallow_hb(partid
);
461 xpc_mark_partition_inactive(part
);
463 if (part
->reason
== xpReactivating
) {
464 /* interrupting ourselves results in activating partition */
465 xpc_request_partition_reactivation(part
);
472 xpc_activate_partition(struct xpc_partition
*part
)
474 short partid
= XPC_PARTID(part
);
475 unsigned long irq_flags
;
476 struct task_struct
*kthread
;
478 spin_lock_irqsave(&part
->act_lock
, irq_flags
);
480 DBUG_ON(part
->act_state
!= XPC_P_INACTIVE
);
482 part
->act_state
= XPC_P_ACTIVATION_REQ
;
483 XPC_SET_REASON(part
, xpCloneKThread
, __LINE__
);
485 spin_unlock_irqrestore(&part
->act_lock
, irq_flags
);
487 kthread
= kthread_run(xpc_activating
, (void *)((u64
)partid
), "xpc%02d",
489 if (IS_ERR(kthread
)) {
490 spin_lock_irqsave(&part
->act_lock
, irq_flags
);
491 part
->act_state
= XPC_P_INACTIVE
;
492 XPC_SET_REASON(part
, xpCloneKThreadFailed
, __LINE__
);
493 spin_unlock_irqrestore(&part
->act_lock
, irq_flags
);
498 xpc_activate_kthreads(struct xpc_channel
*ch
, int needed
)
500 int idle
= atomic_read(&ch
->kthreads_idle
);
501 int assigned
= atomic_read(&ch
->kthreads_assigned
);
504 DBUG_ON(needed
<= 0);
507 wakeup
= (needed
> idle
) ? idle
: needed
;
510 dev_dbg(xpc_chan
, "wakeup %d idle kthreads, partid=%d, "
511 "channel=%d\n", wakeup
, ch
->partid
, ch
->number
);
513 /* only wakeup the requested number of kthreads */
514 wake_up_nr(&ch
->idle_wq
, wakeup
);
520 if (needed
+ assigned
> ch
->kthreads_assigned_limit
) {
521 needed
= ch
->kthreads_assigned_limit
- assigned
;
526 dev_dbg(xpc_chan
, "create %d new kthreads, partid=%d, channel=%d\n",
527 needed
, ch
->partid
, ch
->number
);
529 xpc_create_kthreads(ch
, needed
, 0);
533 * This function is where XPC's kthreads wait for messages to deliver.
536 xpc_kthread_waitmsgs(struct xpc_partition
*part
, struct xpc_channel
*ch
)
539 /* deliver messages to their intended recipients */
541 while (xpc_n_of_deliverable_msgs(ch
) > 0 &&
542 !(ch
->flags
& XPC_C_DISCONNECTING
)) {
546 if (atomic_inc_return(&ch
->kthreads_idle
) >
547 ch
->kthreads_idle_limit
) {
548 /* too many idle kthreads on this channel */
549 atomic_dec(&ch
->kthreads_idle
);
553 dev_dbg(xpc_chan
, "idle kthread calling "
554 "wait_event_interruptible_exclusive()\n");
556 (void)wait_event_interruptible_exclusive(ch
->idle_wq
,
557 (xpc_n_of_deliverable_msgs(ch
) > 0 ||
558 (ch
->flags
& XPC_C_DISCONNECTING
)));
560 atomic_dec(&ch
->kthreads_idle
);
562 } while (!(ch
->flags
& XPC_C_DISCONNECTING
));
566 xpc_kthread_start(void *args
)
568 short partid
= XPC_UNPACK_ARG1(args
);
569 u16 ch_number
= XPC_UNPACK_ARG2(args
);
570 struct xpc_partition
*part
= &xpc_partitions
[partid
];
571 struct xpc_channel
*ch
;
573 unsigned long irq_flags
;
575 dev_dbg(xpc_chan
, "kthread starting, partid=%d, channel=%d\n",
578 ch
= &part
->channels
[ch_number
];
580 if (!(ch
->flags
& XPC_C_DISCONNECTING
)) {
582 /* let registerer know that connection has been established */
584 spin_lock_irqsave(&ch
->lock
, irq_flags
);
585 if (!(ch
->flags
& XPC_C_CONNECTEDCALLOUT
)) {
586 ch
->flags
|= XPC_C_CONNECTEDCALLOUT
;
587 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
589 xpc_connected_callout(ch
);
591 spin_lock_irqsave(&ch
->lock
, irq_flags
);
592 ch
->flags
|= XPC_C_CONNECTEDCALLOUT_MADE
;
593 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
596 * It is possible that while the callout was being
597 * made that the remote partition sent some messages.
598 * If that is the case, we may need to activate
599 * additional kthreads to help deliver them. We only
600 * need one less than total #of messages to deliver.
602 n_needed
= xpc_n_of_deliverable_msgs(ch
) - 1;
603 if (n_needed
> 0 && !(ch
->flags
& XPC_C_DISCONNECTING
))
604 xpc_activate_kthreads(ch
, n_needed
);
607 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
610 xpc_kthread_waitmsgs(part
, ch
);
613 /* let registerer know that connection is disconnecting */
615 spin_lock_irqsave(&ch
->lock
, irq_flags
);
616 if ((ch
->flags
& XPC_C_CONNECTEDCALLOUT_MADE
) &&
617 !(ch
->flags
& XPC_C_DISCONNECTINGCALLOUT
)) {
618 ch
->flags
|= XPC_C_DISCONNECTINGCALLOUT
;
619 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
621 xpc_disconnect_callout(ch
, xpDisconnecting
);
623 spin_lock_irqsave(&ch
->lock
, irq_flags
);
624 ch
->flags
|= XPC_C_DISCONNECTINGCALLOUT_MADE
;
626 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
628 if (atomic_dec_return(&ch
->kthreads_assigned
) == 0 &&
629 atomic_dec_return(&part
->nchannels_engaged
) == 0) {
630 xpc_indicate_partition_disengaged(part
);
633 xpc_msgqueue_deref(ch
);
635 dev_dbg(xpc_chan
, "kthread exiting, partid=%d, channel=%d\n",
638 xpc_part_deref(part
);
643 * For each partition that XPC has established communications with, there is
644 * a minimum of one kernel thread assigned to perform any operation that
645 * may potentially sleep or block (basically the callouts to the asynchronous
646 * functions registered via xpc_connect()).
648 * Additional kthreads are created and destroyed by XPC as the workload
651 * A kthread is assigned to one of the active channels that exists for a given
655 xpc_create_kthreads(struct xpc_channel
*ch
, int needed
,
656 int ignore_disconnecting
)
658 unsigned long irq_flags
;
659 u64 args
= XPC_PACK_ARGS(ch
->partid
, ch
->number
);
660 struct xpc_partition
*part
= &xpc_partitions
[ch
->partid
];
661 struct task_struct
*kthread
;
663 while (needed
-- > 0) {
666 * The following is done on behalf of the newly created
667 * kthread. That kthread is responsible for doing the
668 * counterpart to the following before it exits.
670 if (ignore_disconnecting
) {
671 if (!atomic_inc_not_zero(&ch
->kthreads_assigned
)) {
672 /* kthreads assigned had gone to zero */
674 XPC_C_DISCONNECTINGCALLOUT_MADE
));
678 } else if (ch
->flags
& XPC_C_DISCONNECTING
) {
681 } else if (atomic_inc_return(&ch
->kthreads_assigned
) == 1 &&
682 atomic_inc_return(&part
->nchannels_engaged
) == 1) {
683 xpc_indicate_partition_engaged(part
);
685 (void)xpc_part_ref(part
);
686 xpc_msgqueue_ref(ch
);
688 kthread
= kthread_run(xpc_kthread_start
, (void *)args
,
689 "xpc%02dc%d", ch
->partid
, ch
->number
);
690 if (IS_ERR(kthread
)) {
691 /* the fork failed */
694 * NOTE: if (ignore_disconnecting &&
695 * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
696 * then we'll deadlock if all other kthreads assigned
697 * to this channel are blocked in the channel's
698 * registerer, because the only thing that will unblock
699 * them is the xpDisconnecting callout that this
700 * failed kthread_run() would have made.
703 if (atomic_dec_return(&ch
->kthreads_assigned
) == 0 &&
704 atomic_dec_return(&part
->nchannels_engaged
) == 0) {
705 xpc_indicate_partition_disengaged(part
);
707 xpc_msgqueue_deref(ch
);
708 xpc_part_deref(part
);
710 if (atomic_read(&ch
->kthreads_assigned
) <
711 ch
->kthreads_idle_limit
) {
713 * Flag this as an error only if we have an
714 * insufficient #of kthreads for the channel
717 spin_lock_irqsave(&ch
->lock
, irq_flags
);
718 XPC_DISCONNECT_CHANNEL(ch
, xpLackOfResources
,
720 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
728 xpc_disconnect_wait(int ch_number
)
730 unsigned long irq_flags
;
732 struct xpc_partition
*part
;
733 struct xpc_channel
*ch
;
734 int wakeup_channel_mgr
;
736 /* now wait for all callouts to the caller's function to cease */
737 for (partid
= 0; partid
< xp_max_npartitions
; partid
++) {
738 part
= &xpc_partitions
[partid
];
740 if (!xpc_part_ref(part
))
743 ch
= &part
->channels
[ch_number
];
745 if (!(ch
->flags
& XPC_C_WDISCONNECT
)) {
746 xpc_part_deref(part
);
750 wait_for_completion(&ch
->wdisconnect_wait
);
752 spin_lock_irqsave(&ch
->lock
, irq_flags
);
753 DBUG_ON(!(ch
->flags
& XPC_C_DISCONNECTED
));
754 wakeup_channel_mgr
= 0;
756 if (ch
->delayed_chctl_flags
) {
757 if (part
->act_state
!= XPC_P_DEACTIVATING
) {
758 spin_lock(&part
->chctl_lock
);
759 part
->chctl
.flags
[ch
->number
] |=
760 ch
->delayed_chctl_flags
;
761 spin_unlock(&part
->chctl_lock
);
762 wakeup_channel_mgr
= 1;
764 ch
->delayed_chctl_flags
= 0;
767 ch
->flags
&= ~XPC_C_WDISCONNECT
;
768 spin_unlock_irqrestore(&ch
->lock
, irq_flags
);
770 if (wakeup_channel_mgr
)
771 xpc_wakeup_channel_mgr(part
);
773 xpc_part_deref(part
);
778 xpc_do_exit(enum xp_retval reason
)
781 int active_part_count
, printed_waiting_msg
= 0;
782 struct xpc_partition
*part
;
783 unsigned long printmsg_time
, disengage_timeout
= 0;
785 /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */
786 DBUG_ON(xpc_exiting
== 1);
789 * Let the heartbeat checker thread and the discovery thread
790 * (if one is running) know that they should exit. Also wake up
791 * the heartbeat checker thread in case it's sleeping.
794 wake_up_interruptible(&xpc_activate_IRQ_wq
);
796 /* wait for the discovery thread to exit */
797 wait_for_completion(&xpc_discovery_exited
);
799 /* wait for the heartbeat checker thread to exit */
800 wait_for_completion(&xpc_hb_checker_exited
);
802 /* sleep for a 1/3 of a second or so */
803 (void)msleep_interruptible(300);
805 /* wait for all partitions to become inactive */
807 printmsg_time
= jiffies
+ (XPC_DEACTIVATE_PRINTMSG_INTERVAL
* HZ
);
808 xpc_disengage_timedout
= 0;
811 active_part_count
= 0;
813 for (partid
= 0; partid
< xp_max_npartitions
; partid
++) {
814 part
= &xpc_partitions
[partid
];
816 if (xpc_partition_disengaged(part
) &&
817 part
->act_state
== XPC_P_INACTIVE
) {
823 XPC_DEACTIVATE_PARTITION(part
, reason
);
825 if (part
->disengage_timeout
> disengage_timeout
)
826 disengage_timeout
= part
->disengage_timeout
;
829 if (xpc_any_partition_engaged()) {
830 if (time_is_before_jiffies(printmsg_time
)) {
831 dev_info(xpc_part
, "waiting for remote "
832 "partitions to deactivate, timeout in "
833 "%ld seconds\n", (disengage_timeout
-
835 printmsg_time
= jiffies
+
836 (XPC_DEACTIVATE_PRINTMSG_INTERVAL
* HZ
);
837 printed_waiting_msg
= 1;
840 } else if (active_part_count
> 0) {
841 if (printed_waiting_msg
) {
842 dev_info(xpc_part
, "waiting for local partition"
844 printed_waiting_msg
= 0;
848 if (!xpc_disengage_timedout
) {
849 dev_info(xpc_part
, "all partitions have "
855 /* sleep for a 1/3 of a second or so */
856 (void)msleep_interruptible(300);
860 DBUG_ON(xpc_any_partition_engaged());
861 DBUG_ON(xpc_any_hbs_allowed() != 0);
863 /* indicate to others that our reserved page is uninitialized */
864 xpc_rsvd_page
->stamp
= 0;
866 if (reason
== xpUnloading
) {
867 (void)unregister_die_notifier(&xpc_die_notifier
);
868 (void)unregister_reboot_notifier(&xpc_reboot_notifier
);
871 /* clear the interface to XPC's functions */
872 xpc_clear_interface();
875 unregister_sysctl_table(xpc_sysctl
);
877 kfree(xpc_partitions
);
878 kfree(xpc_remote_copy_buffer_base
);
887 * This function is called when the system is being rebooted.
890 xpc_system_reboot(struct notifier_block
*nb
, unsigned long event
, void *unused
)
892 enum xp_retval reason
;
896 reason
= xpSystemReboot
;
899 reason
= xpSystemHalt
;
902 reason
= xpSystemPoweroff
;
905 reason
= xpSystemGoingDown
;
913 * Notify other partitions to deactivate from us by first disengaging from all
914 * references to our memory.
917 xpc_die_deactivate(void)
919 struct xpc_partition
*part
;
922 long time
, printmsg_time
, disengage_timeout
;
924 /* keep xpc_hb_checker thread from doing anything (just in case) */
927 xpc_disallow_all_hbs(); /*indicate we're deactivated */
929 for (partid
= 0; partid
< xp_max_npartitions
; partid
++) {
930 part
= &xpc_partitions
[partid
];
932 if (xpc_partition_engaged(partid
) ||
933 part
->act_state
!= XPC_P_INACTIVE
) {
934 xpc_request_partition_deactivation(part
);
935 xpc_indicate_partition_disengaged(part
);
940 printmsg_time
= time
+
941 (XPC_DEACTIVATE_PRINTMSG_INTERVAL
* sn_rtc_cycles_per_second
);
942 disengage_timeout
= time
+
943 (xpc_disengage_timelimit
* sn_rtc_cycles_per_second
);
946 * Though we requested that all other partitions deactivate from us,
947 * we only wait until they've all disengaged.
951 any_engaged
= xpc_any_partition_engaged();
953 dev_info(xpc_part
, "all partitions have deactivated\n");
958 if (time
>= disengage_timeout
) {
959 for (partid
= 0; partid
< xp_max_npartitions
;
961 if (xpc_partition_engaged(partid
)) {
962 dev_info(xpc_part
, "deactivate from "
963 "remote partition %d timed "
970 if (time
>= printmsg_time
) {
971 dev_info(xpc_part
, "waiting for remote partitions to "
972 "deactivate, timeout in %ld seconds\n",
973 (disengage_timeout
- time
) /
974 sn_rtc_cycles_per_second
);
975 printmsg_time
= time
+
976 (XPC_DEACTIVATE_PRINTMSG_INTERVAL
*
977 sn_rtc_cycles_per_second
);
983 * This function is called when the system is being restarted or halted due
984 * to some sort of system failure. If this is the case we need to notify the
985 * other partitions to disengage from all references to our memory.
986 * This function can also be called when our heartbeater could be offlined
987 * for a time. In this case we need to notify other partitions to not worry
988 * about the lack of a heartbeat.
991 xpc_system_die(struct notifier_block
*nb
, unsigned long event
, void *unused
)
994 case DIE_MACHINE_RESTART
:
995 case DIE_MACHINE_HALT
:
996 xpc_die_deactivate();
999 case DIE_KDEBUG_ENTER
:
1000 /* Should lack of heartbeat be ignored by other partitions? */
1001 if (!xpc_kdebug_ignore
)
1005 case DIE_MCA_MONARCH_ENTER
:
1006 case DIE_INIT_MONARCH_ENTER
:
1007 xpc_offline_heartbeat();
1010 case DIE_KDEBUG_LEAVE
:
1011 /* Is lack of heartbeat being ignored by other partitions? */
1012 if (!xpc_kdebug_ignore
)
1016 case DIE_MCA_MONARCH_LEAVE
:
1017 case DIE_INIT_MONARCH_LEAVE
:
1018 xpc_online_heartbeat();
1030 struct xpc_partition
*part
;
1031 struct task_struct
*kthread
;
1036 * The ia64-sn2 architecture supports at most 64 partitions.
1037 * And the inability to unregister remote amos restricts us
1038 * further to only support exactly 64 partitions on this
1039 * architecture, no less.
1041 if (xp_max_npartitions
!= 64)
1044 ret
= xpc_init_sn2();
1048 } else if (is_uv()) {
1055 snprintf(xpc_part
->bus_id
, BUS_ID_SIZE
, "part");
1056 snprintf(xpc_chan
->bus_id
, BUS_ID_SIZE
, "chan");
1058 buf_size
= max(XPC_RP_VARS_SIZE
,
1059 XPC_RP_HEADER_SIZE
+ XP_NASID_MASK_BYTES
);
1060 xpc_remote_copy_buffer
= xpc_kmalloc_cacheline_aligned(buf_size
,
1062 &xpc_remote_copy_buffer_base
);
1063 if (xpc_remote_copy_buffer
== NULL
) {
1064 dev_err(xpc_part
, "can't get memory for remote copy buffer\n");
1069 xpc_partitions
= kzalloc(sizeof(struct xpc_partition
) *
1070 xp_max_npartitions
, GFP_KERNEL
);
1071 if (xpc_partitions
== NULL
) {
1072 dev_err(xpc_part
, "can't get memory for partition structure\n");
1078 * The first few fields of each entry of xpc_partitions[] need to
1079 * be initialized now so that calls to xpc_connect() and
1080 * xpc_disconnect() can be made prior to the activation of any remote
1081 * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE
1082 * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING
1083 * PARTITION HAS BEEN ACTIVATED.
1085 for (partid
= 0; partid
< xp_max_npartitions
; partid
++) {
1086 part
= &xpc_partitions
[partid
];
1088 DBUG_ON((u64
)part
!= L1_CACHE_ALIGN((u64
)part
));
1090 part
->activate_IRQ_rcvd
= 0;
1091 spin_lock_init(&part
->act_lock
);
1092 part
->act_state
= XPC_P_INACTIVE
;
1093 XPC_SET_REASON(part
, 0, 0);
1095 init_timer(&part
->disengage_timer
);
1096 part
->disengage_timer
.function
=
1097 xpc_timeout_partition_disengage
;
1098 part
->disengage_timer
.data
= (unsigned long)part
;
1100 part
->setup_state
= XPC_P_UNSET
;
1101 init_waitqueue_head(&part
->teardown_wq
);
1102 atomic_set(&part
->references
, 0);
1105 xpc_sysctl
= register_sysctl_table(xpc_sys_dir
);
1108 * Fill the partition reserved page with the information needed by
1109 * other partitions to discover we are alive and establish initial
1112 xpc_rsvd_page
= xpc_setup_rsvd_page();
1113 if (xpc_rsvd_page
== NULL
) {
1114 dev_err(xpc_part
, "can't setup our reserved page\n");
1119 /* add ourselves to the reboot_notifier_list */
1120 ret
= register_reboot_notifier(&xpc_reboot_notifier
);
1122 dev_warn(xpc_part
, "can't register reboot notifier\n");
1124 /* add ourselves to the die_notifier list */
1125 ret
= register_die_notifier(&xpc_die_notifier
);
1127 dev_warn(xpc_part
, "can't register die notifier\n");
1130 * The real work-horse behind xpc. This processes incoming
1131 * interrupts and monitors remote heartbeats.
1133 kthread
= kthread_run(xpc_hb_checker
, NULL
, XPC_HB_CHECK_THREAD_NAME
);
1134 if (IS_ERR(kthread
)) {
1135 dev_err(xpc_part
, "failed while forking hb check thread\n");
1141 * Startup a thread that will attempt to discover other partitions to
1142 * activate based on info provided by SAL. This new thread is short
1143 * lived and will exit once discovery is complete.
1145 kthread
= kthread_run(xpc_initiate_discovery
, NULL
,
1146 XPC_DISCOVERY_THREAD_NAME
);
1147 if (IS_ERR(kthread
)) {
1148 dev_err(xpc_part
, "failed while forking discovery thread\n");
1150 /* mark this new thread as a non-starter */
1151 complete(&xpc_discovery_exited
);
1153 xpc_do_exit(xpUnloading
);
1157 /* set the interface to point at XPC's functions */
1158 xpc_set_interface(xpc_initiate_connect
, xpc_initiate_disconnect
,
1159 xpc_initiate_send
, xpc_initiate_send_notify
,
1160 xpc_initiate_received
, xpc_initiate_partid_to_nasids
);
1164 /* initialization was not successful */
1166 /* indicate to others that our reserved page is uninitialized */
1167 xpc_rsvd_page
->stamp
= 0;
1169 (void)unregister_die_notifier(&xpc_die_notifier
);
1170 (void)unregister_reboot_notifier(&xpc_reboot_notifier
);
1173 unregister_sysctl_table(xpc_sysctl
);
1174 kfree(xpc_partitions
);
1176 kfree(xpc_remote_copy_buffer_base
);
1185 module_init(xpc_init
);
1190 xpc_do_exit(xpUnloading
);
1193 module_exit(xpc_exit
);
1195 MODULE_AUTHOR("Silicon Graphics, Inc.");
1196 MODULE_DESCRIPTION("Cross Partition Communication (XPC) support");
1197 MODULE_LICENSE("GPL");
1199 module_param(xpc_hb_interval
, int, 0);
1200 MODULE_PARM_DESC(xpc_hb_interval
, "Number of seconds between "
1201 "heartbeat increments.");
1203 module_param(xpc_hb_check_interval
, int, 0);
1204 MODULE_PARM_DESC(xpc_hb_check_interval
, "Number of seconds between "
1205 "heartbeat checks.");
1207 module_param(xpc_disengage_timelimit
, int, 0);
1208 MODULE_PARM_DESC(xpc_disengage_timelimit
, "Number of seconds to wait "
1209 "for disengage to complete.");
1211 module_param(xpc_kdebug_ignore
, int, 0);
1212 MODULE_PARM_DESC(xpc_kdebug_ignore
, "Should lack of heartbeat be ignored by "
1213 "other partitions when dropping into kdebug.");