/* * 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) 2004-2006 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: * * . We currently have no way to determine which nasid an IPI came * from. Thus, xpc_IPI_send() 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 #include #include #include #include #include #include #include /* 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 = { .bus_id = {0}, /* set to "part" at xpc_init() time */ .driver = &xpc_dbg_name }; struct device xpc_chan_dbg_subname = { .bus_id = {0}, /* 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_request_timelimit = XPC_DISENGAGE_REQUEST_DEFAULT_TIMELIMIT; static int xpc_disengage_request_min_timelimit = 0; static int xpc_disengage_request_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_request_timelimit", .data = &xpc_disengage_request_timelimit, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &proc_dointvec_minmax, .strategy = &sysctl_intvec, .extra1 = &xpc_disengage_request_min_timelimit, .extra2 = &xpc_disengage_request_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 request was timed out */ int xpc_disengage_request_timedout; /* #of IRQs received */ static atomic_t xpc_act_IRQ_rcvd; /* IRQ handler notifies this wait queue on receipt of an IRQ */ static DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq); static unsigned long xpc_hb_check_timeout; /* 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 struct timer_list xpc_hb_timer; 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, }; /* * Timer function to enforce the timelimit on the partition disengage request. */ static void xpc_timeout_partition_disengage_request(unsigned long data) { struct xpc_partition *part = (struct xpc_partition *) data; DBUG_ON(jiffies < part->disengage_request_timeout); (void) xpc_partition_disengaged(part); DBUG_ON(part->disengage_request_timeout != 0); DBUG_ON(xpc_partition_engaged(1UL << XPC_PARTID(part)) != 0); } /* * Notify the heartbeat check thread that an IRQ has been received. */ static irqreturn_t xpc_act_IRQ_handler(int irq, void *dev_id) { atomic_inc(&xpc_act_IRQ_rcvd); wake_up_interruptible(&xpc_act_IRQ_wq); return IRQ_HANDLED; } /* * 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_vars->heartbeat++; if (jiffies >= xpc_hb_check_timeout) { wake_up_interruptible(&xpc_act_IRQ_wq); } xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ); add_timer(&xpc_hb_timer); } /* * This thread is responsible for nearly all of the partition * activation/deactivation. */ static int xpc_hb_checker(void *ignore) { int last_IRQ_count = 0; int new_IRQ_count; int force_IRQ=0; /* this thread was marked active by xpc_hb_init() */ daemonize(XPC_HB_CHECK_THREAD_NAME); set_cpus_allowed(current, cpumask_of_cpu(XPC_HB_CHECK_CPU)); xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ); while (!(volatile int) xpc_exiting) { dev_dbg(xpc_part, "woke up with %d ticks rem; %d IRQs have " "been received\n", (int) (xpc_hb_check_timeout - jiffies), atomic_read(&xpc_act_IRQ_rcvd) - last_IRQ_count); /* checking of remote heartbeats is skewed by IRQ handling */ if (jiffies >= xpc_hb_check_timeout) { dev_dbg(xpc_part, "checking remote heartbeats\n"); xpc_check_remote_hb(); /* * We need to periodically recheck to ensure no * IPI/AMO pairs have been missed. That check * must always reset xpc_hb_check_timeout. */ force_IRQ = 1; } /* check for outstanding IRQs */ new_IRQ_count = atomic_read(&xpc_act_IRQ_rcvd); if (last_IRQ_count < new_IRQ_count || force_IRQ != 0) { force_IRQ = 0; dev_dbg(xpc_part, "found an IRQ to process; will be " "resetting xpc_hb_check_timeout\n"); last_IRQ_count += xpc_identify_act_IRQ_sender(); if (last_IRQ_count < new_IRQ_count) { /* retry once to help avoid missing AMO */ (void) xpc_identify_act_IRQ_sender(); } last_IRQ_count = new_IRQ_count; xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ); } /* wait for IRQ or timeout */ (void) wait_event_interruptible(xpc_act_IRQ_wq, (last_IRQ_count < atomic_read(&xpc_act_IRQ_rcvd) || jiffies >= xpc_hb_check_timeout || (volatile int) xpc_exiting)); } 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) { daemonize(XPC_DISCOVERY_THREAD_NAME); xpc_discovery(); dev_dbg(xpc_part, "discovery thread is exiting\n"); /* mark this thread as having exited */ complete(&xpc_discovery_exited); return 0; } /* * Establish first contact with the remote partititon. This involves pulling * the XPC per partition variables from the remote partition and waiting for * the remote partition to pull ours. */ static enum xpc_retval xpc_make_first_contact(struct xpc_partition *part) { enum xpc_retval ret; while ((ret = xpc_pull_remote_vars_part(part)) != xpcSuccess) { if (ret != xpcRetry) { XPC_DEACTIVATE_PARTITION(part, ret); return ret; } dev_dbg(xpc_chan, "waiting to make first contact with " "partition %d\n", XPC_PARTID(part)); /* wait a 1/4 of a second or so */ (void) msleep_interruptible(250); if (part->act_state == XPC_P_DEACTIVATING) { return part->reason; } } return xpc_mark_partition_active(part); } /* * The first kthread assigned to a newly activated partition is the one * created by XPC HB with which it calls xpc_partition_up(). 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_DEACTIVATING || atomic_read(&part->nchannels_active) > 0 || !xpc_partition_disengaged(part)) { xpc_process_channel_activity(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 || (volatile u64) part->local_IPI_amo != 0 || ((volatile u8) part->act_state == XPC_P_DEACTIVATING && atomic_read(&part->nchannels_active) == 0 && xpc_partition_disengaged(part)))); atomic_set(&part->channel_mgr_requests, 1); // >>> Does it need to wakeup periodically as well? In case we // >>> miscalculated the #of kthreads to wakeup or create? } } /* * 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 until the partition * goes down. At which time the kthread will teardown the XPC infrastructure * and then exit. * * XPC HB will put the remote partition's XPC per partition specific variables * physical address into xpc_partitions[partid].remote_vars_part_pa prior to * calling xpc_partition_up(). */ static void xpc_partition_up(struct xpc_partition *part) { DBUG_ON(part->channels != NULL); dev_dbg(xpc_chan, "activating partition %d\n", XPC_PARTID(part)); if (xpc_setup_infrastructure(part) != xpcSuccess) { return; } /* * The kthread that XPC HB called us with will become the * channel manager for this partition. It will not return * back to XPC HB until the partition's XPC infrastructure * has been dismantled. */ (void) xpc_part_ref(part); /* this will always succeed */ if (xpc_make_first_contact(part) == xpcSuccess) { xpc_channel_mgr(part); } xpc_part_deref(part); xpc_teardown_infrastructure(part); } static int xpc_activating(void *__partid) { partid_t partid = (u64) __partid; struct xpc_partition *part = &xpc_partitions[partid]; unsigned long irq_flags; struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; int ret; DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS); spin_lock_irqsave(&part->act_lock, irq_flags); if (part->act_state == XPC_P_DEACTIVATING) { part->act_state = XPC_P_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_ACTIVATION_REQ); part->act_state = XPC_P_ACTIVATING; XPC_SET_REASON(part, 0, 0); spin_unlock_irqrestore(&part->act_lock, irq_flags); dev_dbg(xpc_part, "bringing partition %d up\n", partid); daemonize("xpc%02d", partid); /* * This thread needs to run at a realtime priority to prevent a * significant performance degradation. */ ret = sched_setscheduler(current, SCHED_FIFO, ¶m); if (ret != 0) { dev_warn(xpc_part, "unable to set pid %d to a realtime " "priority, ret=%d\n", current->pid, ret); } /* allow this thread and its children to run on any CPU */ set_cpus_allowed(current, CPU_MASK_ALL); /* * Register the remote partition's AMOs with SAL so it can handle * and cleanup errors within that address range should the remote * partition go down. We don't unregister this range because it is * difficult to tell when outstanding writes to the remote partition * are finished and thus when it is safe to unregister. This should * not result in wasted space in the SAL xp_addr_region table because * we should get the same page for remote_amos_page_pa after module * reloads and system reboots. */ if (sn_register_xp_addr_region(part->remote_amos_page_pa, PAGE_SIZE, 1) < 0) { dev_warn(xpc_part, "xpc_partition_up(%d) failed to register " "xp_addr region\n", partid); spin_lock_irqsave(&part->act_lock, irq_flags); part->act_state = XPC_P_INACTIVE; XPC_SET_REASON(part, xpcPhysAddrRegFailed, __LINE__); spin_unlock_irqrestore(&part->act_lock, irq_flags); part->remote_rp_pa = 0; return 0; } xpc_allow_hb(partid, xpc_vars); xpc_IPI_send_activated(part); /* * xpc_partition_up() holds this thread and marks this partition as * XPC_P_ACTIVE by calling xpc_hb_mark_active(). */ (void) xpc_partition_up(part); xpc_disallow_hb(partid, xpc_vars); xpc_mark_partition_inactive(part); if (part->reason == xpcReactivating) { /* interrupting ourselves results in activating partition */ xpc_IPI_send_reactivate(part); } return 0; } void xpc_activate_partition(struct xpc_partition *part) { partid_t partid = XPC_PARTID(part); unsigned long irq_flags; pid_t pid; spin_lock_irqsave(&part->act_lock, irq_flags); DBUG_ON(part->act_state != XPC_P_INACTIVE); part->act_state = XPC_P_ACTIVATION_REQ; XPC_SET_REASON(part, xpcCloneKThread, __LINE__); spin_unlock_irqrestore(&part->act_lock, irq_flags); pid = kernel_thread(xpc_activating, (void *) ((u64) partid), 0); if (unlikely(pid <= 0)) { spin_lock_irqsave(&part->act_lock, irq_flags); part->act_state = XPC_P_INACTIVE; XPC_SET_REASON(part, xpcCloneKThreadFailed, __LINE__); spin_unlock_irqrestore(&part->act_lock, irq_flags); } } /* * Handle the receipt of a SGI_XPC_NOTIFY IRQ by seeing whether the specified * partition actually sent it. Since SGI_XPC_NOTIFY IRQs may be shared by more * than one partition, we use an AMO_t structure per partition to indicate * whether a partition has sent an IPI or not. >>> If it has, then wake up the * associated kthread to handle it. * * All SGI_XPC_NOTIFY IRQs received by XPC are the result of IPIs sent by XPC * running on other partitions. * * Noteworthy Arguments: * * irq - Interrupt ReQuest number. NOT USED. * * dev_id - partid of IPI's potential sender. */ irqreturn_t xpc_notify_IRQ_handler(int irq, void *dev_id) { partid_t partid = (partid_t) (u64) dev_id; struct xpc_partition *part = &xpc_partitions[partid]; DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS); if (xpc_part_ref(part)) { xpc_check_for_channel_activity(part); xpc_part_deref(part); } return IRQ_HANDLED; } /* * Check to see if xpc_notify_IRQ_handler() dropped any IPIs on the floor * because the write to their associated IPI amo completed after the IRQ/IPI * was received. */ void xpc_dropped_IPI_check(struct xpc_partition *part) { if (xpc_part_ref(part)) { xpc_check_for_channel_activity(part); part->dropped_IPI_timer.expires = jiffies + XPC_P_DROPPED_IPI_WAIT; add_timer(&part->dropped_IPI_timer); xpc_part_deref(part); } } 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; // >>>should never be less than 0 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 ((volatile s64) ch->w_local_GP.get < (volatile s64) ch->w_remote_GP.put && !((volatile u32) ch->flags & XPC_C_DISCONNECTING)) { xpc_deliver_msg(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, ((volatile s64) ch->w_local_GP.get < (volatile s64) ch->w_remote_GP.put || ((volatile u32) ch->flags & XPC_C_DISCONNECTING))); atomic_dec(&ch->kthreads_idle); } while (!((volatile u32) ch->flags & XPC_C_DISCONNECTING)); } static int xpc_daemonize_kthread(void *args) { partid_t 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; daemonize("xpc%02dc%d", partid, ch_number); 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 = ch->w_remote_GP.put - ch->w_local_GP.get - 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, xpcDisconnecting); 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) { if (atomic_dec_return(&part->nchannels_engaged) == 0) { xpc_mark_partition_disengaged(part); xpc_IPI_send_disengage(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; pid_t pid; u64 args = XPC_PACK_ARGS(ch->partid, ch->number); struct xpc_partition *part = &xpc_partitions[ch->partid]; 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) { if (atomic_inc_return(&part->nchannels_engaged) == 1) xpc_mark_partition_engaged(part); } (void) xpc_part_ref(part); xpc_msgqueue_ref(ch); pid = kernel_thread(xpc_daemonize_kthread, (void *) args, 0); if (pid < 0) { /* 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 xpcDisconnecting callout that this * failed kernel_thread would have made. */ if (atomic_dec_return(&ch->kthreads_assigned) == 0 && atomic_dec_return(&part->nchannels_engaged) == 0) { xpc_mark_partition_disengaged(part); xpc_IPI_send_disengage(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, xpcLackOfResources, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); } break; } ch->kthreads_created++; // >>> temporary debug only!!! } } void xpc_disconnect_wait(int ch_number) { unsigned long irq_flags; partid_t 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 = 1; partid < XP_MAX_PARTITIONS; 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_IPI_flags) { if (part->act_state != XPC_P_DEACTIVATING) { spin_lock(&part->IPI_lock); XPC_SET_IPI_FLAGS(part->local_IPI_amo, ch->number, ch->delayed_IPI_flags); spin_unlock(&part->IPI_lock); wakeup_channel_mgr = 1; } ch->delayed_IPI_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 void xpc_do_exit(enum xpc_retval reason) { partid_t partid; int active_part_count, printed_waiting_msg = 0; struct xpc_partition *part; unsigned long printmsg_time, disengage_request_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_act_IRQ_wq); /* ignore all incoming interrupts */ free_irq(SGI_XPC_ACTIVATE, NULL); /* 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_DISENGAGE_PRINTMSG_INTERVAL * HZ); xpc_disengage_request_timedout = 0; do { active_part_count = 0; for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) { part = &xpc_partitions[partid]; if (xpc_partition_disengaged(part) && part->act_state == XPC_P_INACTIVE) { continue; } active_part_count++; XPC_DEACTIVATE_PARTITION(part, reason); if (part->disengage_request_timeout > disengage_request_timeout) { disengage_request_timeout = part->disengage_request_timeout; } } if (xpc_partition_engaged(-1UL)) { if (time_after(jiffies, printmsg_time)) { dev_info(xpc_part, "waiting for remote " "partitions to disengage, timeout in " "%ld seconds\n", (disengage_request_timeout - jiffies) / HZ); printmsg_time = jiffies + (XPC_DISENGAGE_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 disengage\n"); printed_waiting_msg = 0; } } else { if (!xpc_disengage_request_timedout) { dev_info(xpc_part, "all partitions have " "disengaged\n"); } break; } /* sleep for a 1/3 of a second or so */ (void) msleep_interruptible(300); } while (1); DBUG_ON(xpc_partition_engaged(-1UL)); /* indicate to others that our reserved page is uninitialized */ xpc_rsvd_page->vars_pa = 0; /* now it's time to eliminate our heartbeat */ del_timer_sync(&xpc_hb_timer); DBUG_ON(xpc_vars->heartbeating_to_mask != 0); if (reason == xpcUnloading) { /* take ourselves off of the reboot_notifier_list */ (void) unregister_reboot_notifier(&xpc_reboot_notifier); /* take ourselves off of the die_notifier list */ (void) unregister_die_notifier(&xpc_die_notifier); } /* close down protections for IPI operations */ xpc_restrict_IPI_ops(); /* clear the interface to XPC's functions */ xpc_clear_interface(); if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } kfree(xpc_remote_copy_buffer_base); } /* * 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 xpc_retval reason; switch (event) { case SYS_RESTART: reason = xpcSystemReboot; break; case SYS_HALT: reason = xpcSystemHalt; break; case SYS_POWER_OFF: reason = xpcSystemPoweroff; break; default: reason = xpcSystemGoingDown; } xpc_do_exit(reason); return NOTIFY_DONE; } /* * Notify other partitions to disengage from all references to our memory. */ static void xpc_die_disengage(void) { struct xpc_partition *part; partid_t partid; unsigned long engaged; long time, printmsg_time, disengage_request_timeout; /* keep xpc_hb_checker thread from doing anything (just in case) */ xpc_exiting = 1; xpc_vars->heartbeating_to_mask = 0; /* indicate we're deactivated */ for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) { part = &xpc_partitions[partid]; if (!XPC_SUPPORTS_DISENGAGE_REQUEST(part-> remote_vars_version)) { /* just in case it was left set by an earlier XPC */ xpc_clear_partition_engaged(1UL << partid); continue; } if (xpc_partition_engaged(1UL << partid) || part->act_state != XPC_P_INACTIVE) { xpc_request_partition_disengage(part); xpc_mark_partition_disengaged(part); xpc_IPI_send_disengage(part); } } time = rtc_time(); printmsg_time = time + (XPC_DISENGAGE_PRINTMSG_INTERVAL * sn_rtc_cycles_per_second); disengage_request_timeout = time + (xpc_disengage_request_timelimit * sn_rtc_cycles_per_second); /* wait for all other partitions to disengage from us */ while (1) { engaged = xpc_partition_engaged(-1UL); if (!engaged) { dev_info(xpc_part, "all partitions have disengaged\n"); break; } time = rtc_time(); if (time >= disengage_request_timeout) { for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) { if (engaged & (1UL << partid)) { dev_info(xpc_part, "disengage from " "remote partition %d timed " "out\n", partid); } } break; } if (time >= printmsg_time) { dev_info(xpc_part, "waiting for remote partitions to " "disengage, timeout in %ld seconds\n", (disengage_request_timeout - time) / sn_rtc_cycles_per_second); printmsg_time = time + (XPC_DISENGAGE_PRINTMSG_INTERVAL * sn_rtc_cycles_per_second); } } } /* * 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) { switch (event) { case DIE_MACHINE_RESTART: case DIE_MACHINE_HALT: xpc_die_disengage(); 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_vars->heartbeat++; xpc_vars->heartbeat_offline = 1; 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_vars->heartbeat++; xpc_vars->heartbeat_offline = 0; break; } return NOTIFY_DONE; } int __init xpc_init(void) { int ret; partid_t partid; struct xpc_partition *part; pid_t pid; size_t buf_size; if (!ia64_platform_is("sn2")) { return -ENODEV; } buf_size = max(XPC_RP_VARS_SIZE, XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES); xpc_remote_copy_buffer = xpc_kmalloc_cacheline_aligned(buf_size, GFP_KERNEL, &xpc_remote_copy_buffer_base); if (xpc_remote_copy_buffer == NULL) return -ENOMEM; snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part"); snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan"); xpc_sysctl = register_sysctl_table(xpc_sys_dir); /* * 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 = 1; partid < XP_MAX_PARTITIONS; partid++) { part = &xpc_partitions[partid]; DBUG_ON((u64) part != L1_CACHE_ALIGN((u64) part)); part->act_IRQ_rcvd = 0; spin_lock_init(&part->act_lock); part->act_state = XPC_P_INACTIVE; XPC_SET_REASON(part, 0, 0); init_timer(&part->disengage_request_timer); part->disengage_request_timer.function = xpc_timeout_partition_disengage_request; part->disengage_request_timer.data = (unsigned long) part; part->setup_state = XPC_P_UNSET; init_waitqueue_head(&part->teardown_wq); atomic_set(&part->references, 0); } /* * Open up protections for IPI operations (and AMO operations on * Shub 1.1 systems). */ xpc_allow_IPI_ops(); /* * Interrupts being processed will increment this atomic variable and * awaken the heartbeat thread which will process the interrupts. */ atomic_set(&xpc_act_IRQ_rcvd, 0); /* * This is safe to do before the xpc_hb_checker thread has started * because the handler releases a wait queue. If an interrupt is * received before the thread is waiting, it will not go to sleep, * but rather immediately process the interrupt. */ ret = request_irq(SGI_XPC_ACTIVATE, xpc_act_IRQ_handler, 0, "xpc hb", NULL); if (ret != 0) { dev_err(xpc_part, "can't register ACTIVATE IRQ handler, " "errno=%d\n", -ret); xpc_restrict_IPI_ops(); if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } kfree(xpc_remote_copy_buffer_base); return -EBUSY; } /* * Fill the partition reserved page with the information needed by * other partitions to discover we are alive and establish initial * communications. */ xpc_rsvd_page = xpc_rsvd_page_init(); if (xpc_rsvd_page == NULL) { dev_err(xpc_part, "could not setup our reserved page\n"); free_irq(SGI_XPC_ACTIVATE, NULL); xpc_restrict_IPI_ops(); if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } kfree(xpc_remote_copy_buffer_base); return -EBUSY; } /* 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"); } /* * Set the beating to other partitions into motion. This is * the last requirement for other partitions' discovery to * initiate communications with us. */ init_timer(&xpc_hb_timer); xpc_hb_timer.function = xpc_hb_beater; xpc_hb_beater(0); /* * The real work-horse behind xpc. This processes incoming * interrupts and monitors remote heartbeats. */ pid = kernel_thread(xpc_hb_checker, NULL, 0); if (pid < 0) { dev_err(xpc_part, "failed while forking hb check thread\n"); /* indicate to others that our reserved page is uninitialized */ xpc_rsvd_page->vars_pa = 0; /* take ourselves off of the reboot_notifier_list */ (void) unregister_reboot_notifier(&xpc_reboot_notifier); /* take ourselves off of the die_notifier list */ (void) unregister_die_notifier(&xpc_die_notifier); del_timer_sync(&xpc_hb_timer); free_irq(SGI_XPC_ACTIVATE, NULL); xpc_restrict_IPI_ops(); if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } kfree(xpc_remote_copy_buffer_base); return -EBUSY; } /* * 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. */ pid = kernel_thread(xpc_initiate_discovery, NULL, 0); if (pid < 0) { 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(xpcUnloading); return -EBUSY; } /* set the interface to point at XPC's functions */ xpc_set_interface(xpc_initiate_connect, xpc_initiate_disconnect, xpc_initiate_allocate, xpc_initiate_send, xpc_initiate_send_notify, xpc_initiate_received, xpc_initiate_partid_to_nasids); return 0; } module_init(xpc_init); void __exit xpc_exit(void) { xpc_do_exit(xpcUnloading); } 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_request_timelimit, int, 0); MODULE_PARM_DESC(xpc_disengage_request_timelimit, "Number of seconds to wait " "for disengage request 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.");