/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (c) 2004-2009 Silicon Graphics, Inc. All Rights Reserved. */ /* * Cross Partition Communication (XPC) support - standard version. * * XPC provides a message passing capability that crosses partition * boundaries. This module is made up of two parts: * * partition This part detects the presence/absence of other * partitions. It provides a heartbeat and monitors * the heartbeats of other partitions. * * channel This part manages the channels and sends/receives * messages across them to/from other partitions. * * There are a couple of additional functions residing in XP, which * provide an interface to XPC for its users. * * * Caveats: * * . Currently on sn2, we have no way to determine which nasid an IRQ * came from. Thus, xpc_send_IRQ_sn2() does a remote amo write * followed by an IPI. The amo indicates where data is to be pulled * from, so after the IPI arrives, the remote partition checks the amo * word. The IPI can actually arrive before the amo however, so other * code must periodically check for this case. Also, remote amo * operations do not reliably time out. Thus we do a remote PIO read * solely to know whether the remote partition is down and whether we * should stop sending IPIs to it. This remote PIO read operation is * set up in a special nofault region so SAL knows to ignore (and * cleanup) any errors due to the remote amo write, PIO read, and/or * PIO write operations. * * If/when new hardware solves this IPI problem, we should abandon * the current approach. * */ #include #include #include #include #include #include #include #include "xpc.h" /* define two XPC debug device structures to be used with dev_dbg() et al */ struct device_driver xpc_dbg_name = { .name = "xpc" }; struct device xpc_part_dbg_subname = { .init_name = "", /* set to "part" at xpc_init() time */ .driver = &xpc_dbg_name }; struct device xpc_chan_dbg_subname = { .init_name = "", /* set to "chan" at xpc_init() time */ .driver = &xpc_dbg_name }; struct device *xpc_part = &xpc_part_dbg_subname; struct device *xpc_chan = &xpc_chan_dbg_subname; static int xpc_kdebug_ignore; /* systune related variables for /proc/sys directories */ static int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL; static int xpc_hb_min_interval = 1; static int xpc_hb_max_interval = 10; static int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_INTERVAL; static int xpc_hb_check_min_interval = 10; static int xpc_hb_check_max_interval = 120; int xpc_disengage_timelimit = XPC_DISENGAGE_DEFAULT_TIMELIMIT; static int xpc_disengage_min_timelimit; /* = 0 */ static int xpc_disengage_max_timelimit = 120; static ctl_table xpc_sys_xpc_hb_dir[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "hb_interval", .data = &xpc_hb_interval, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &proc_dointvec_minmax, .strategy = &sysctl_intvec, .extra1 = &xpc_hb_min_interval, .extra2 = &xpc_hb_max_interval}, { .ctl_name = CTL_UNNUMBERED, .procname = "hb_check_interval", .data = &xpc_hb_check_interval, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &proc_dointvec_minmax, .strategy = &sysctl_intvec, .extra1 = &xpc_hb_check_min_interval, .extra2 = &xpc_hb_check_max_interval}, {} }; static ctl_table xpc_sys_xpc_dir[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "hb", .mode = 0555, .child = xpc_sys_xpc_hb_dir}, { .ctl_name = CTL_UNNUMBERED, .procname = "disengage_timelimit", .data = &xpc_disengage_timelimit, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &proc_dointvec_minmax, .strategy = &sysctl_intvec, .extra1 = &xpc_disengage_min_timelimit, .extra2 = &xpc_disengage_max_timelimit}, {} }; static ctl_table xpc_sys_dir[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "xpc", .mode = 0555, .child = xpc_sys_xpc_dir}, {} }; static struct ctl_table_header *xpc_sysctl; /* non-zero if any remote partition disengage was timed out */ int xpc_disengage_timedout; /* #of activate IRQs received and not yet processed */ int xpc_activate_IRQ_rcvd; DEFINE_SPINLOCK(xpc_activate_IRQ_rcvd_lock); /* IRQ handler notifies this wait queue on receipt of an IRQ */ DECLARE_WAIT_QUEUE_HEAD(xpc_activate_IRQ_wq); static unsigned long xpc_hb_check_timeout; static struct timer_list xpc_hb_timer; /* notification that the xpc_hb_checker thread has exited */ static DECLARE_COMPLETION(xpc_hb_checker_exited); /* notification that the xpc_discovery thread has exited */ static DECLARE_COMPLETION(xpc_discovery_exited); static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *); static int xpc_system_reboot(struct notifier_block *, unsigned long, void *); static struct notifier_block xpc_reboot_notifier = { .notifier_call = xpc_system_reboot, }; static int xpc_system_die(struct notifier_block *, unsigned long, void *); static struct notifier_block xpc_die_notifier = { .notifier_call = xpc_system_die, }; int (*xpc_setup_partitions_sn) (void); void (*xpc_teardown_partitions_sn) (void); enum xp_retval (*xpc_get_partition_rsvd_page_pa) (void *buf, u64 *cookie, unsigned long *rp_pa, size_t *len); int (*xpc_setup_rsvd_page_sn) (struct xpc_rsvd_page *rp); void (*xpc_allow_hb) (short partid); void (*xpc_disallow_hb) (short partid); void (*xpc_disallow_all_hbs) (void); void (*xpc_heartbeat_init) (void); void (*xpc_heartbeat_exit) (void); void (*xpc_increment_heartbeat) (void); void (*xpc_offline_heartbeat) (void); void (*xpc_online_heartbeat) (void); enum xp_retval (*xpc_get_remote_heartbeat) (struct xpc_partition *part); enum xp_retval (*xpc_make_first_contact) (struct xpc_partition *part); void (*xpc_notify_senders_of_disconnect) (struct xpc_channel *ch); u64 (*xpc_get_chctl_all_flags) (struct xpc_partition *part); enum xp_retval (*xpc_setup_msg_structures) (struct xpc_channel *ch); void (*xpc_teardown_msg_structures) (struct xpc_channel *ch); void (*xpc_process_msg_chctl_flags) (struct xpc_partition *part, int ch_number); int (*xpc_n_of_deliverable_payloads) (struct xpc_channel *ch); void *(*xpc_get_deliverable_payload) (struct xpc_channel *ch); void (*xpc_request_partition_activation) (struct xpc_rsvd_page *remote_rp, unsigned long remote_rp_pa, int nasid); void (*xpc_request_partition_reactivation) (struct xpc_partition *part); void (*xpc_request_partition_deactivation) (struct xpc_partition *part); void (*xpc_cancel_partition_deactivation_request) (struct xpc_partition *part); void (*xpc_process_activate_IRQ_rcvd) (void); enum xp_retval (*xpc_setup_ch_structures_sn) (struct xpc_partition *part); void (*xpc_teardown_ch_structures_sn) (struct xpc_partition *part); void (*xpc_indicate_partition_engaged) (struct xpc_partition *part); int (*xpc_partition_engaged) (short partid); int (*xpc_any_partition_engaged) (void); void (*xpc_indicate_partition_disengaged) (struct xpc_partition *part); void (*xpc_assume_partition_disengaged) (short partid); void (*xpc_send_chctl_closerequest) (struct xpc_channel *ch, unsigned long *irq_flags); void (*xpc_send_chctl_closereply) (struct xpc_channel *ch, unsigned long *irq_flags); void (*xpc_send_chctl_openrequest) (struct xpc_channel *ch, unsigned long *irq_flags); void (*xpc_send_chctl_openreply) (struct xpc_channel *ch, unsigned long *irq_flags); enum xp_retval (*xpc_save_remote_msgqueue_pa) (struct xpc_channel *ch, unsigned long msgqueue_pa); enum xp_retval (*xpc_send_payload) (struct xpc_channel *ch, u32 flags, void *payload, u16 payload_size, u8 notify_type, xpc_notify_func func, void *key); void (*xpc_received_payload) (struct xpc_channel *ch, void *payload); /* * Timer function to enforce the timelimit on the partition disengage. */ static void xpc_timeout_partition_disengage(unsigned long data) { struct xpc_partition *part = (struct xpc_partition *)data; DBUG_ON(time_is_after_jiffies(part->disengage_timeout)); (void)xpc_partition_disengaged(part); DBUG_ON(part->disengage_timeout != 0); DBUG_ON(xpc_partition_engaged(XPC_PARTID(part))); } /* * Timer to produce the heartbeat. The timer structures function is * already set when this is initially called. A tunable is used to * specify when the next timeout should occur. */ static void xpc_hb_beater(unsigned long dummy) { xpc_increment_heartbeat(); if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) wake_up_interruptible(&xpc_activate_IRQ_wq); xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ); add_timer(&xpc_hb_timer); } static void xpc_start_hb_beater(void) { xpc_heartbeat_init(); init_timer(&xpc_hb_timer); xpc_hb_timer.function = xpc_hb_beater; xpc_hb_beater(0); } static void xpc_stop_hb_beater(void) { del_timer_sync(&xpc_hb_timer); xpc_heartbeat_exit(); } /* * At periodic intervals, scan through all active partitions and ensure * their heartbeat is still active. If not, the partition is deactivated. */ static void xpc_check_remote_hb(void) { struct xpc_partition *part; short partid; enum xp_retval ret; for (partid = 0; partid < xp_max_npartitions; partid++) { if (xpc_exiting) break; if (partid == xp_partition_id) continue; part = &xpc_partitions[partid]; if (part->act_state == XPC_P_AS_INACTIVE || part->act_state == XPC_P_AS_DEACTIVATING) { continue; } ret = xpc_get_remote_heartbeat(part); if (ret != xpSuccess) XPC_DEACTIVATE_PARTITION(part, ret); } } /* * This thread is responsible for nearly all of the partition * activation/deactivation. */ static int xpc_hb_checker(void *ignore) { int force_IRQ = 0; /* this thread was marked active by xpc_hb_init() */ set_cpus_allowed_ptr(current, cpumask_of(XPC_HB_CHECK_CPU)); /* set our heartbeating to other partitions into motion */ xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ); xpc_start_hb_beater(); while (!xpc_exiting) { dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have " "been received\n", (int)(xpc_hb_check_timeout - jiffies), xpc_activate_IRQ_rcvd); /* checking of remote heartbeats is skewed by IRQ handling */ if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) { xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ); dev_dbg(xpc_part, "checking remote heartbeats\n"); xpc_check_remote_hb(); /* * On sn2 we need to periodically recheck to ensure no * IRQ/amo pairs have been missed. */ if (is_shub()) force_IRQ = 1; } /* check for outstanding IRQs */ if (xpc_activate_IRQ_rcvd > 0 || force_IRQ != 0) { force_IRQ = 0; dev_dbg(xpc_part, "processing activate IRQs " "received\n"); xpc_process_activate_IRQ_rcvd(); } /* wait for IRQ or timeout */ (void)wait_event_interruptible(xpc_activate_IRQ_wq, (time_is_before_eq_jiffies( xpc_hb_check_timeout) || xpc_activate_IRQ_rcvd > 0 || xpc_exiting)); } xpc_stop_hb_beater(); dev_dbg(xpc_part, "heartbeat checker is exiting\n"); /* mark this thread as having exited */ complete(&xpc_hb_checker_exited); return 0; } /* * This thread will attempt to discover other partitions to activate * based on info provided by SAL. This new thread is short lived and * will exit once discovery is complete. */ static int xpc_initiate_discovery(void *ignore) { xpc_discovery(); dev_dbg(xpc_part, "discovery thread is exiting\n"); /* mark this thread as having exited */ complete(&xpc_discovery_exited); return 0; } /* * The first kthread assigned to a newly activated partition is the one * created by XPC HB with which it calls xpc_activating(). XPC hangs on to * that kthread until the partition is brought down, at which time that kthread * returns back to XPC HB. (The return of that kthread will signify to XPC HB * that XPC has dismantled all communication infrastructure for the associated * partition.) This kthread becomes the channel manager for that partition. * * Each active partition has a channel manager, who, besides connecting and * disconnecting channels, will ensure that each of the partition's connected * channels has the required number of assigned kthreads to get the work done. */ static void xpc_channel_mgr(struct xpc_partition *part) { while (part->act_state != XPC_P_AS_DEACTIVATING || atomic_read(&part->nchannels_active) > 0 || !xpc_partition_disengaged(part)) { xpc_process_sent_chctl_flags(part); /* * Wait until we've been requested to activate kthreads or * all of the channel's message queues have been torn down or * a signal is pending. * * The channel_mgr_requests is set to 1 after being awakened, * This is done to prevent the channel mgr from making one pass * through the loop for each request, since he will * be servicing all the requests in one pass. The reason it's * set to 1 instead of 0 is so that other kthreads will know * that the channel mgr is running and won't bother trying to * wake him up. */ atomic_dec(&part->channel_mgr_requests); (void)wait_event_interruptible(part->channel_mgr_wq, (atomic_read(&part->channel_mgr_requests) > 0 || part->chctl.all_flags != 0 || (part->act_state == XPC_P_AS_DEACTIVATING && atomic_read(&part->nchannels_active) == 0 && xpc_partition_disengaged(part)))); atomic_set(&part->channel_mgr_requests, 1); } } /* * Guarantee that the kzalloc'd memory is cacheline aligned. */ void * xpc_kzalloc_cacheline_aligned(size_t size, gfp_t flags, void **base) { /* see if kzalloc will give us cachline aligned memory by default */ *base = kzalloc(size, flags); if (*base == NULL) return NULL; if ((u64)*base == L1_CACHE_ALIGN((u64)*base)) return *base; kfree(*base); /* nope, we'll have to do it ourselves */ *base = kzalloc(size + L1_CACHE_BYTES, flags); if (*base == NULL) return NULL; return (void *)L1_CACHE_ALIGN((u64)*base); } /* * Setup the channel structures necessary to support XPartition Communication * between the specified remote partition and the local one. */ static enum xp_retval xpc_setup_ch_structures(struct xpc_partition *part) { enum xp_retval ret; int ch_number; struct xpc_channel *ch; short partid = XPC_PARTID(part); /* * Allocate all of the channel structures as a contiguous chunk of * memory. */ DBUG_ON(part->channels != NULL); part->channels = kzalloc(sizeof(struct xpc_channel) * XPC_MAX_NCHANNELS, GFP_KERNEL); if (part->channels == NULL) { dev_err(xpc_chan, "can't get memory for channels\n"); return xpNoMemory; } /* allocate the remote open and close args */ part->remote_openclose_args = xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL, &part-> remote_openclose_args_base); if (part->remote_openclose_args == NULL) { dev_err(xpc_chan, "can't get memory for remote connect args\n"); ret = xpNoMemory; goto out_1; } part->chctl.all_flags = 0; spin_lock_init(&part->chctl_lock); atomic_set(&part->channel_mgr_requests, 1); init_waitqueue_head(&part->channel_mgr_wq); part->nchannels = XPC_MAX_NCHANNELS; atomic_set(&part->nchannels_active, 0); atomic_set(&part->nchannels_engaged, 0); for (ch_number = 0; ch_number < part->nchannels; ch_number++) { ch = &part->channels[ch_number]; ch->partid = partid; ch->number = ch_number; ch->flags = XPC_C_DISCONNECTED; atomic_set(&ch->kthreads_assigned, 0); atomic_set(&ch->kthreads_idle, 0); atomic_set(&ch->kthreads_active, 0); atomic_set(&ch->references, 0); atomic_set(&ch->n_to_notify, 0); spin_lock_init(&ch->lock); init_completion(&ch->wdisconnect_wait); atomic_set(&ch->n_on_msg_allocate_wq, 0); init_waitqueue_head(&ch->msg_allocate_wq); init_waitqueue_head(&ch->idle_wq); } ret = xpc_setup_ch_structures_sn(part); if (ret != xpSuccess) goto out_2; /* * With the setting of the partition setup_state to XPC_P_SS_SETUP, * we're declaring that this partition is ready to go. */ part->setup_state = XPC_P_SS_SETUP; return xpSuccess; /* setup of ch structures failed */ out_2: kfree(part->remote_openclose_args_base); part->remote_openclose_args = NULL; out_1: kfree(part->channels); part->channels = NULL; return ret; } /* * Teardown the channel structures necessary to support XPartition Communication * between the specified remote partition and the local one. */ static void xpc_teardown_ch_structures(struct xpc_partition *part) { DBUG_ON(atomic_read(&part->nchannels_engaged) != 0); DBUG_ON(atomic_read(&part->nchannels_active) != 0); /* * Make this partition inaccessible to local processes by marking it * as no longer setup. Then wait before proceeding with the teardown * until all existing references cease. */ DBUG_ON(part->setup_state != XPC_P_SS_SETUP); part->setup_state = XPC_P_SS_WTEARDOWN; wait_event(part->teardown_wq, (atomic_read(&part->references) == 0)); /* now we can begin tearing down the infrastructure */ xpc_teardown_ch_structures_sn(part); kfree(part->remote_openclose_args_base); part->remote_openclose_args = NULL; kfree(part->channels); part->channels = NULL; part->setup_state = XPC_P_SS_TORNDOWN; } /* * When XPC HB determines that a partition has come up, it will create a new * kthread and that kthread will call this function to attempt to set up the * basic infrastructure used for Cross Partition Communication with the newly * upped partition. * * The kthread that was created by XPC HB and which setup the XPC * infrastructure will remain assigned to the partition becoming the channel * manager for that partition until the partition is deactivating, at which * time the kthread will teardown the XPC infrastructure and then exit. */ static int xpc_activating(void *__partid) { short partid = (u64)__partid; struct xpc_partition *part = &xpc_partitions[partid]; unsigned long irq_flags; DBUG_ON(partid < 0 || partid >= xp_max_npartitions); spin_lock_irqsave(&part->act_lock, irq_flags); if (part->act_state == XPC_P_AS_DEACTIVATING) { part->act_state = XPC_P_AS_INACTIVE; spin_unlock_irqrestore(&part->act_lock, irq_flags); part->remote_rp_pa = 0; return 0; } /* indicate the thread is activating */ DBUG_ON(part->act_state != XPC_P_AS_ACTIVATION_REQ); part->act_state = XPC_P_AS_ACTIVATING; XPC_SET_REASON(part, 0, 0); spin_unlock_irqrestore(&part->act_lock, irq_flags); dev_dbg(xpc_part, "activating partition %d\n", partid); xpc_allow_hb(partid); if (xpc_setup_ch_structures(part) == xpSuccess) { (void)xpc_part_ref(part); /* this will always succeed */ if (xpc_make_first_contact(part) == xpSuccess) { xpc_mark_partition_active(part); xpc_channel_mgr(part); /* won't return until partition is deactivating */ } xpc_part_deref(part); xpc_teardown_ch_structures(part); } xpc_disallow_hb(partid); xpc_mark_partition_inactive(part); if (part->reason == xpReactivating) { /* interrupting ourselves results in activating partition */ xpc_request_partition_reactivation(part); } return 0; } void xpc_activate_partition(struct xpc_partition *part) { short partid = XPC_PARTID(part); unsigned long irq_flags; struct task_struct *kthread; spin_lock_irqsave(&part->act_lock, irq_flags); DBUG_ON(part->act_state != XPC_P_AS_INACTIVE); part->act_state = XPC_P_AS_ACTIVATION_REQ; XPC_SET_REASON(part, xpCloneKThread, __LINE__); spin_unlock_irqrestore(&part->act_lock, irq_flags); kthread = kthread_run(xpc_activating, (void *)((u64)partid), "xpc%02d", partid); if (IS_ERR(kthread)) { spin_lock_irqsave(&part->act_lock, irq_flags); part->act_state = XPC_P_AS_INACTIVE; XPC_SET_REASON(part, xpCloneKThreadFailed, __LINE__); spin_unlock_irqrestore(&part->act_lock, irq_flags); } } void xpc_activate_kthreads(struct xpc_channel *ch, int needed) { int idle = atomic_read(&ch->kthreads_idle); int assigned = atomic_read(&ch->kthreads_assigned); int wakeup; DBUG_ON(needed <= 0); if (idle > 0) { wakeup = (needed > idle) ? idle : needed; needed -= wakeup; dev_dbg(xpc_chan, "wakeup %d idle kthreads, partid=%d, " "channel=%d\n", wakeup, ch->partid, ch->number); /* only wakeup the requested number of kthreads */ wake_up_nr(&ch->idle_wq, wakeup); } if (needed <= 0) return; if (needed + assigned > ch->kthreads_assigned_limit) { needed = ch->kthreads_assigned_limit - assigned; if (needed <= 0) return; } dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n", needed, ch->partid, ch->number); xpc_create_kthreads(ch, needed, 0); } /* * This function is where XPC's kthreads wait for messages to deliver. */ static void xpc_kthread_waitmsgs(struct xpc_partition *part, struct xpc_channel *ch) { do { /* deliver messages to their intended recipients */ while (xpc_n_of_deliverable_payloads(ch) > 0 && !(ch->flags & XPC_C_DISCONNECTING)) { xpc_deliver_payload(ch); } if (atomic_inc_return(&ch->kthreads_idle) > ch->kthreads_idle_limit) { /* too many idle kthreads on this channel */ atomic_dec(&ch->kthreads_idle); break; } dev_dbg(xpc_chan, "idle kthread calling " "wait_event_interruptible_exclusive()\n"); (void)wait_event_interruptible_exclusive(ch->idle_wq, (xpc_n_of_deliverable_payloads(ch) > 0 || (ch->flags & XPC_C_DISCONNECTING))); atomic_dec(&ch->kthreads_idle); } while (!(ch->flags & XPC_C_DISCONNECTING)); } static int xpc_kthread_start(void *args) { short partid = XPC_UNPACK_ARG1(args); u16 ch_number = XPC_UNPACK_ARG2(args); struct xpc_partition *part = &xpc_partitions[partid]; struct xpc_channel *ch; int n_needed; unsigned long irq_flags; dev_dbg(xpc_chan, "kthread starting, partid=%d, channel=%d\n", partid, ch_number); ch = &part->channels[ch_number]; if (!(ch->flags & XPC_C_DISCONNECTING)) { /* let registerer know that connection has been established */ spin_lock_irqsave(&ch->lock, irq_flags); if (!(ch->flags & XPC_C_CONNECTEDCALLOUT)) { ch->flags |= XPC_C_CONNECTEDCALLOUT; spin_unlock_irqrestore(&ch->lock, irq_flags); xpc_connected_callout(ch); spin_lock_irqsave(&ch->lock, irq_flags); ch->flags |= XPC_C_CONNECTEDCALLOUT_MADE; spin_unlock_irqrestore(&ch->lock, irq_flags); /* * It is possible that while the callout was being * made that the remote partition sent some messages. * If that is the case, we may need to activate * additional kthreads to help deliver them. We only * need one less than total #of messages to deliver. */ n_needed = xpc_n_of_deliverable_payloads(ch) - 1; if (n_needed > 0 && !(ch->flags & XPC_C_DISCONNECTING)) xpc_activate_kthreads(ch, n_needed); } else { spin_unlock_irqrestore(&ch->lock, irq_flags); } xpc_kthread_waitmsgs(part, ch); } /* let registerer know that connection is disconnecting */ spin_lock_irqsave(&ch->lock, irq_flags); if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) && !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) { ch->flags |= XPC_C_DISCONNECTINGCALLOUT; spin_unlock_irqrestore(&ch->lock, irq_flags); xpc_disconnect_callout(ch, xpDisconnecting); spin_lock_irqsave(&ch->lock, irq_flags); ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE; } spin_unlock_irqrestore(&ch->lock, irq_flags); if (atomic_dec_return(&ch->kthreads_assigned) == 0 && atomic_dec_return(&part->nchannels_engaged) == 0) { xpc_indicate_partition_disengaged(part); } xpc_msgqueue_deref(ch); dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n", partid, ch_number); xpc_part_deref(part); return 0; } /* * For each partition that XPC has established communications with, there is * a minimum of one kernel thread assigned to perform any operation that * may potentially sleep or block (basically the callouts to the asynchronous * functions registered via xpc_connect()). * * Additional kthreads are created and destroyed by XPC as the workload * demands. * * A kthread is assigned to one of the active channels that exists for a given * partition. */ void xpc_create_kthreads(struct xpc_channel *ch, int needed, int ignore_disconnecting) { unsigned long irq_flags; u64 args = XPC_PACK_ARGS(ch->partid, ch->number); struct xpc_partition *part = &xpc_partitions[ch->partid]; struct task_struct *kthread; while (needed-- > 0) { /* * The following is done on behalf of the newly created * kthread. That kthread is responsible for doing the * counterpart to the following before it exits. */ if (ignore_disconnecting) { if (!atomic_inc_not_zero(&ch->kthreads_assigned)) { /* kthreads assigned had gone to zero */ BUG_ON(!(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE)); break; } } else if (ch->flags & XPC_C_DISCONNECTING) { break; } else if (atomic_inc_return(&ch->kthreads_assigned) == 1 && atomic_inc_return(&part->nchannels_engaged) == 1) { xpc_indicate_partition_engaged(part); } (void)xpc_part_ref(part); xpc_msgqueue_ref(ch); kthread = kthread_run(xpc_kthread_start, (void *)args, "xpc%02dc%d", ch->partid, ch->number); if (IS_ERR(kthread)) { /* the fork failed */ /* * NOTE: if (ignore_disconnecting && * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true, * then we'll deadlock if all other kthreads assigned * to this channel are blocked in the channel's * registerer, because the only thing that will unblock * them is the xpDisconnecting callout that this * failed kthread_run() would have made. */ if (atomic_dec_return(&ch->kthreads_assigned) == 0 && atomic_dec_return(&part->nchannels_engaged) == 0) { xpc_indicate_partition_disengaged(part); } xpc_msgqueue_deref(ch); xpc_part_deref(part); if (atomic_read(&ch->kthreads_assigned) < ch->kthreads_idle_limit) { /* * Flag this as an error only if we have an * insufficient #of kthreads for the channel * to function. */ spin_lock_irqsave(&ch->lock, irq_flags); XPC_DISCONNECT_CHANNEL(ch, xpLackOfResources, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); } break; } } } void xpc_disconnect_wait(int ch_number) { unsigned long irq_flags; short partid; struct xpc_partition *part; struct xpc_channel *ch; int wakeup_channel_mgr; /* now wait for all callouts to the caller's function to cease */ for (partid = 0; partid < xp_max_npartitions; partid++) { part = &xpc_partitions[partid]; if (!xpc_part_ref(part)) continue; ch = &part->channels[ch_number]; if (!(ch->flags & XPC_C_WDISCONNECT)) { xpc_part_deref(part); continue; } wait_for_completion(&ch->wdisconnect_wait); spin_lock_irqsave(&ch->lock, irq_flags); DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED)); wakeup_channel_mgr = 0; if (ch->delayed_chctl_flags) { if (part->act_state != XPC_P_AS_DEACTIVATING) { spin_lock(&part->chctl_lock); part->chctl.flags[ch->number] |= ch->delayed_chctl_flags; spin_unlock(&part->chctl_lock); wakeup_channel_mgr = 1; } ch->delayed_chctl_flags = 0; } ch->flags &= ~XPC_C_WDISCONNECT; spin_unlock_irqrestore(&ch->lock, irq_flags); if (wakeup_channel_mgr) xpc_wakeup_channel_mgr(part); xpc_part_deref(part); } } static int xpc_setup_partitions(void) { short partid; struct xpc_partition *part; xpc_partitions = kzalloc(sizeof(struct xpc_partition) * xp_max_npartitions, GFP_KERNEL); if (xpc_partitions == NULL) { dev_err(xpc_part, "can't get memory for partition structure\n"); return -ENOMEM; } /* * The first few fields of each entry of xpc_partitions[] need to * be initialized now so that calls to xpc_connect() and * xpc_disconnect() can be made prior to the activation of any remote * partition. NOTE THAT NONE OF THE OTHER FIELDS BELONGING TO THESE * ENTRIES ARE MEANINGFUL UNTIL AFTER AN ENTRY'S CORRESPONDING * PARTITION HAS BEEN ACTIVATED. */ for (partid = 0; partid < xp_max_npartitions; partid++) { part = &xpc_partitions[partid]; DBUG_ON((u64)part != L1_CACHE_ALIGN((u64)part)); part->activate_IRQ_rcvd = 0; spin_lock_init(&part->act_lock); part->act_state = XPC_P_AS_INACTIVE; XPC_SET_REASON(part, 0, 0); init_timer(&part->disengage_timer); part->disengage_timer.function = xpc_timeout_partition_disengage; part->disengage_timer.data = (unsigned long)part; part->setup_state = XPC_P_SS_UNSET; init_waitqueue_head(&part->teardown_wq); atomic_set(&part->references, 0); } return xpc_setup_partitions_sn(); } static void xpc_teardown_partitions(void) { xpc_teardown_partitions_sn(); kfree(xpc_partitions); } static void xpc_do_exit(enum xp_retval reason) { short partid; int active_part_count, printed_waiting_msg = 0; struct xpc_partition *part; unsigned long printmsg_time, disengage_timeout = 0; /* a 'rmmod XPC' and a 'reboot' cannot both end up here together */ DBUG_ON(xpc_exiting == 1); /* * Let the heartbeat checker thread and the discovery thread * (if one is running) know that they should exit. Also wake up * the heartbeat checker thread in case it's sleeping. */ xpc_exiting = 1; wake_up_interruptible(&xpc_activate_IRQ_wq); /* wait for the discovery thread to exit */ wait_for_completion(&xpc_discovery_exited); /* wait for the heartbeat checker thread to exit */ wait_for_completion(&xpc_hb_checker_exited); /* sleep for a 1/3 of a second or so */ (void)msleep_interruptible(300); /* wait for all partitions to become inactive */ printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ); xpc_disengage_timedout = 0; do { active_part_count = 0; for (partid = 0; partid < xp_max_npartitions; partid++) { part = &xpc_partitions[partid]; if (xpc_partition_disengaged(part) && part->act_state == XPC_P_AS_INACTIVE) { continue; } active_part_count++; XPC_DEACTIVATE_PARTITION(part, reason); if (part->disengage_timeout > disengage_timeout) disengage_timeout = part->disengage_timeout; } if (xpc_any_partition_engaged()) { if (time_is_before_jiffies(printmsg_time)) { dev_info(xpc_part, "waiting for remote " "partitions to deactivate, timeout in " "%ld seconds\n", (disengage_timeout - jiffies) / HZ); printmsg_time = jiffies + (XPC_DEACTIVATE_PRINTMSG_INTERVAL * HZ); printed_waiting_msg = 1; } } else if (active_part_count > 0) { if (printed_waiting_msg) { dev_info(xpc_part, "waiting for local partition" " to deactivate\n"); printed_waiting_msg = 0; } } else { if (!xpc_disengage_timedout) { dev_info(xpc_part, "all partitions have " "deactivated\n"); } break; } /* sleep for a 1/3 of a second or so */ (void)msleep_interruptible(300); } while (1); DBUG_ON(xpc_any_partition_engaged()); xpc_teardown_rsvd_page(); if (reason == xpUnloading) { (void)unregister_die_notifier(&xpc_die_notifier); (void)unregister_reboot_notifier(&xpc_reboot_notifier); } /* clear the interface to XPC's functions */ xpc_clear_interface(); if (xpc_sysctl) unregister_sysctl_table(xpc_sysctl); xpc_teardown_partitions(); if (is_shub()) xpc_exit_sn2(); else if (is_uv()) xpc_exit_uv(); } /* * This function is called when the system is being rebooted. */ static int xpc_system_reboot(struct notifier_block *nb, unsigned long event, void *unused) { enum xp_retval reason; switch (event) { case SYS_RESTART: reason = xpSystemReboot; break; case SYS_HALT: reason = xpSystemHalt; break; case SYS_POWER_OFF: reason = xpSystemPoweroff; break; default: reason = xpSystemGoingDown; } xpc_do_exit(reason); return NOTIFY_DONE; } /* * Notify other partitions to deactivate from us by first disengaging from all * references to our memory. */ static void xpc_die_deactivate(void) { struct xpc_partition *part; short partid; int any_engaged; long keep_waiting; long wait_to_print; /* keep xpc_hb_checker thread from doing anything (just in case) */ xpc_exiting = 1; xpc_disallow_all_hbs(); /*indicate we're deactivated */ for (partid = 0; partid < xp_max_npartitions; partid++) { part = &xpc_partitions[partid]; if (xpc_partition_engaged(partid) || part->act_state != XPC_P_AS_INACTIVE) { xpc_request_partition_deactivation(part); xpc_indicate_partition_disengaged(part); } } /* * Though we requested that all other partitions deactivate from us, * we only wait until they've all disengaged or we've reached the * defined timelimit. * * Given that one iteration through the following while-loop takes * approximately 200 microseconds, calculate the #of loops to take * before bailing and the #of loops before printing a waiting message. */ keep_waiting = xpc_disengage_timelimit * 1000 * 5; wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5; while (1) { any_engaged = xpc_any_partition_engaged(); if (!any_engaged) { dev_info(xpc_part, "all partitions have deactivated\n"); break; } if (!keep_waiting--) { for (partid = 0; partid < xp_max_npartitions; partid++) { if (xpc_partition_engaged(partid)) { dev_info(xpc_part, "deactivate from " "remote partition %d timed " "out\n", partid); } } break; } if (!wait_to_print--) { dev_info(xpc_part, "waiting for remote partitions to " "deactivate, timeout in %ld seconds\n", keep_waiting / (1000 * 5)); wait_to_print = XPC_DEACTIVATE_PRINTMSG_INTERVAL * 1000 * 5; } udelay(200); } } /* * This function is called when the system is being restarted or halted due * to some sort of system failure. If this is the case we need to notify the * other partitions to disengage from all references to our memory. * This function can also be called when our heartbeater could be offlined * for a time. In this case we need to notify other partitions to not worry * about the lack of a heartbeat. */ static int xpc_system_die(struct notifier_block *nb, unsigned long event, void *unused) { #ifdef CONFIG_IA64 /* !!! temporary kludge */ switch (event) { case DIE_MACHINE_RESTART: case DIE_MACHINE_HALT: xpc_die_deactivate(); break; case DIE_KDEBUG_ENTER: /* Should lack of heartbeat be ignored by other partitions? */ if (!xpc_kdebug_ignore) break; /* fall through */ case DIE_MCA_MONARCH_ENTER: case DIE_INIT_MONARCH_ENTER: xpc_offline_heartbeat(); break; case DIE_KDEBUG_LEAVE: /* Is lack of heartbeat being ignored by other partitions? */ if (!xpc_kdebug_ignore) break; /* fall through */ case DIE_MCA_MONARCH_LEAVE: case DIE_INIT_MONARCH_LEAVE: xpc_online_heartbeat(); break; } #else xpc_die_deactivate(); #endif return NOTIFY_DONE; } int __init xpc_init(void) { int ret; struct task_struct *kthread; dev_set_name(xpc_part, "part"); dev_set_name(xpc_chan, "chan"); if (is_shub()) { /* * The ia64-sn2 architecture supports at most 64 partitions. * And the inability to unregister remote amos restricts us * further to only support exactly 64 partitions on this * architecture, no less. */ if (xp_max_npartitions != 64) { dev_err(xpc_part, "max #of partitions not set to 64\n"); ret = -EINVAL; } else { ret = xpc_init_sn2(); } } else if (is_uv()) { ret = xpc_init_uv(); } else { ret = -ENODEV; } if (ret != 0) return ret; ret = xpc_setup_partitions(); if (ret != 0) { dev_err(xpc_part, "can't get memory for partition structure\n"); goto out_1; } xpc_sysctl = register_sysctl_table(xpc_sys_dir); /* * Fill the partition reserved page with the information needed by * other partitions to discover we are alive and establish initial * communications. */ ret = xpc_setup_rsvd_page(); if (ret != 0) { dev_err(xpc_part, "can't setup our reserved page\n"); goto out_2; } /* add ourselves to the reboot_notifier_list */ ret = register_reboot_notifier(&xpc_reboot_notifier); if (ret != 0) dev_warn(xpc_part, "can't register reboot notifier\n"); /* add ourselves to the die_notifier list */ ret = register_die_notifier(&xpc_die_notifier); if (ret != 0) dev_warn(xpc_part, "can't register die notifier\n"); /* * The real work-horse behind xpc. This processes incoming * interrupts and monitors remote heartbeats. */ kthread = kthread_run(xpc_hb_checker, NULL, XPC_HB_CHECK_THREAD_NAME); if (IS_ERR(kthread)) { dev_err(xpc_part, "failed while forking hb check thread\n"); ret = -EBUSY; goto out_3; } /* * Startup a thread that will attempt to discover other partitions to * activate based on info provided by SAL. This new thread is short * lived and will exit once discovery is complete. */ kthread = kthread_run(xpc_initiate_discovery, NULL, XPC_DISCOVERY_THREAD_NAME); if (IS_ERR(kthread)) { dev_err(xpc_part, "failed while forking discovery thread\n"); /* mark this new thread as a non-starter */ complete(&xpc_discovery_exited); xpc_do_exit(xpUnloading); return -EBUSY; } /* set the interface to point at XPC's functions */ xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect, xpc_initiate_send, xpc_initiate_send_notify, xpc_initiate_received, xpc_initiate_partid_to_nasids); return 0; /* initialization was not successful */ out_3: xpc_teardown_rsvd_page(); (void)unregister_die_notifier(&xpc_die_notifier); (void)unregister_reboot_notifier(&xpc_reboot_notifier); out_2: if (xpc_sysctl) unregister_sysctl_table(xpc_sysctl); xpc_teardown_partitions(); out_1: if (is_shub()) xpc_exit_sn2(); else if (is_uv()) xpc_exit_uv(); return ret; } module_init(xpc_init); void __exit xpc_exit(void) { xpc_do_exit(xpUnloading); } module_exit(xpc_exit); MODULE_AUTHOR("Silicon Graphics, Inc."); MODULE_DESCRIPTION("Cross Partition Communication (XPC) support"); MODULE_LICENSE("GPL"); module_param(xpc_hb_interval, int, 0); MODULE_PARM_DESC(xpc_hb_interval, "Number of seconds between " "heartbeat increments."); module_param(xpc_hb_check_interval, int, 0); MODULE_PARM_DESC(xpc_hb_check_interval, "Number of seconds between " "heartbeat checks."); module_param(xpc_disengage_timelimit, int, 0); MODULE_PARM_DESC(xpc_disengage_timelimit, "Number of seconds to wait " "for disengage to complete."); module_param(xpc_kdebug_ignore, int, 0); MODULE_PARM_DESC(xpc_kdebug_ignore, "Should lack of heartbeat be ignored by " "other partitions when dropping into kdebug.");