/*
* 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.
*
* (C) Copyright 2020 Hewlett Packard Enterprise Development LP
* 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 */
static struct device_driver xpc_dbg_name = {
.name = "xpc"
};
static struct device xpc_part_dbg_subname = {
.init_name = "", /* set to "part" at xpc_init() time */
.driver = &xpc_dbg_name
};
static 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[] = {
{
.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[] = {
{
.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_header *xpc_sysctl;
static struct ctl_table_header *xpc_sysctl_hb;
/* 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(struct timer_list *t)
{
struct xpc_partition *part = from_timer(part, t, disengage_timer);
DBUG_ON(time_is_after_jiffies(part->disengage_timeout));
xpc_partition_disengaged_from_timer(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(struct timer_list *unused)
{
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();
timer_setup(&xpc_hb_timer, xpc_hb_beater, 0);
xpc_hb_beater(NULL);
}
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();
}
/* 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 = kcalloc(XPC_MAX_NCHANNELS,
sizeof(struct xpc_channel),
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 = kcalloc(xp_max_npartitions,
sizeof(struct xpc_partition),
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);
timer_setup(&part->disengage_timer,
xpc_timeout_partition_disengage, 0);
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);
if (xpc_sysctl_hb)
unregister_sysctl_table(xpc_sysctl_hb);
xpc_teardown_partitions();
if (is_uv_system())
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)
{
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();
}
return NOTIFY_DONE;
}
static 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_uv_system()) {
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("xpc", xpc_sys_xpc);
xpc_sysctl_hb = register_sysctl("xpc/hb", xpc_sys_xpc_hb);
/*
* 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_hb)
unregister_sysctl_table(xpc_sysctl_hb);
if (xpc_sysctl)
unregister_sysctl_table(xpc_sysctl);
xpc_teardown_partitions();
out_1:
if (is_uv_system())
xpc_exit_uv();
return ret;
}
module_init(xpc_init);
static 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.");
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