--- /dev/null
+/*
+ * 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 <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/kdebug.h>
+#include <linux/kthread.h>
+#include "xpc.h"
+
+#ifdef CONFIG_X86_64
+#include <asm/traps.h>
+#endif
+
+/* 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 struct ctl_table xpc_sys_xpc_hb_dir[] = {
+ {
+ .procname = "hb_interval",
+ .data = &xpc_hb_interval,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &xpc_hb_min_interval,
+ .extra2 = &xpc_hb_max_interval},
+ {
+ .procname = "hb_check_interval",
+ .data = &xpc_hb_check_interval,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &xpc_hb_check_min_interval,
+ .extra2 = &xpc_hb_check_max_interval},
+ {}
+};
+static struct ctl_table xpc_sys_xpc_dir[] = {
+ {
+ .procname = "hb",
+ .mode = 0555,
+ .child = xpc_sys_xpc_hb_dir},
+ {
+ .procname = "disengage_timelimit",
+ .data = &xpc_disengage_timelimit,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &xpc_disengage_min_timelimit,
+ .extra2 = &xpc_disengage_max_timelimit},
+ {}
+};
+static struct ctl_table xpc_sys_dir[] = {
+ {
+ .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,
+};
+
+struct xpc_arch_operations xpc_arch_ops;
+
+/*
+ * 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_arch_ops.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_arch_ops.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_arch_ops.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_arch_ops.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_arch_ops.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_arch_ops.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_arch_ops.setup_ch_structures(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_arch_ops.teardown_ch_structures(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_arch_ops.allow_hb(partid);
+
+ if (xpc_setup_ch_structures(part) == xpSuccess) {
+ (void)xpc_part_ref(part); /* this will always succeed */
+
+ if (xpc_arch_ops.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_arch_ops.disallow_hb(partid);
+ xpc_mark_partition_inactive(part);
+
+ if (part->reason == xpReactivating) {
+ /* interrupting ourselves results in activating partition */
+ xpc_arch_ops.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)
+{
+ int (*n_of_deliverable_payloads) (struct xpc_channel *) =
+ xpc_arch_ops.n_of_deliverable_payloads;
+
+ do {
+ /* deliver messages to their intended recipients */
+
+ while (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,
+ (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;
+ int (*n_of_deliverable_payloads) (struct xpc_channel *) =
+ xpc_arch_ops.n_of_deliverable_payloads;
+
+ 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 = 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_arch_ops.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;
+ void (*indicate_partition_disengaged) (struct xpc_partition *) =
+ xpc_arch_ops.indicate_partition_disengaged;
+
+ 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_arch_ops.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) {
+ 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_arch_ops.setup_partitions();
+}
+
+static void
+xpc_teardown_partitions(void)
+{
+ xpc_arch_ops.teardown_partitions();
+ 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_arch_ops.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_arch_ops.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;
+}
+
+/* Used to only allow one cpu to complete disconnect */
+static unsigned int xpc_die_disconnecting;
+
+/*
+ * 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;
+
+ if (cmpxchg(&xpc_die_disconnecting, 0, 1))
+ return;
+
+ /* keep xpc_hb_checker thread from doing anything (just in case) */
+ xpc_exiting = 1;
+
+ xpc_arch_ops.disallow_all_hbs(); /*indicate we're deactivated */
+
+ for (partid = 0; partid < xp_max_npartitions; partid++) {
+ part = &xpc_partitions[partid];
+
+ if (xpc_arch_ops.partition_engaged(partid) ||
+ part->act_state != XPC_P_AS_INACTIVE) {
+ xpc_arch_ops.request_partition_deactivation(part);
+ xpc_arch_ops.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_arch_ops.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_arch_ops.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 *_die_args)
+{
+#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_arch_ops.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_arch_ops.online_heartbeat();
+ break;
+ }
+#else
+ struct die_args *die_args = _die_args;
+
+ switch (event) {
+ case DIE_TRAP:
+ if (die_args->trapnr == X86_TRAP_DF)
+ xpc_die_deactivate();
+
+ if (((die_args->trapnr == X86_TRAP_MF) ||
+ (die_args->trapnr == X86_TRAP_XF)) &&
+ !user_mode(die_args->regs))
+ xpc_die_deactivate();
+
+ break;
+ case DIE_INT3:
+ case DIE_DEBUG:
+ break;
+ case DIE_OOPS:
+ case DIE_GPF:
+ default:
+ 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.");
Code Review / kvmfornfv.git / blobdiff