/* * 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) 2004-2005 Silicon Graphics, Inc. All Rights Reserved. */ /* * Cross Partition Communication (XPC) channel support. * * This is the part of XPC that manages the channels and * sends/receives messages across them to/from other partitions. * */ #include #include #include #include #include #include #include #include #include "xpc.h" /* * Set up the initial values for the XPartition Communication channels. */ static void xpc_initialize_channels(struct xpc_partition *part, partid_t partid) { int ch_number; struct xpc_channel *ch; 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; ch->local_GP = &part->local_GPs[ch_number]; ch->local_openclose_args = &part->local_openclose_args[ch_number]; 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); sema_init(&ch->msg_to_pull_sema, 1); /* mutex */ sema_init(&ch->wdisconnect_sema, 0); /* event wait */ atomic_set(&ch->n_on_msg_allocate_wq, 0); init_waitqueue_head(&ch->msg_allocate_wq); init_waitqueue_head(&ch->idle_wq); } } /* * Setup the infrastructure necessary to support XPartition Communication * between the specified remote partition and the local one. */ enum xpc_retval xpc_setup_infrastructure(struct xpc_partition *part) { int ret, cpuid; struct timer_list *timer; partid_t partid = XPC_PARTID(part); /* * Zero out MOST of the entry for this partition. Only the fields * starting with `nchannels' will be zeroed. The preceding fields must * remain `viable' across partition ups and downs, since they may be * referenced during this memset() operation. */ memset(&part->nchannels, 0, sizeof(struct xpc_partition) - offsetof(struct xpc_partition, nchannels)); /* * Allocate all of the channel structures as a contiguous chunk of * memory. */ part->channels = kmalloc(sizeof(struct xpc_channel) * XPC_NCHANNELS, GFP_KERNEL); if (part->channels == NULL) { dev_err(xpc_chan, "can't get memory for channels\n"); return xpcNoMemory; } memset(part->channels, 0, sizeof(struct xpc_channel) * XPC_NCHANNELS); part->nchannels = XPC_NCHANNELS; /* allocate all the required GET/PUT values */ part->local_GPs = xpc_kmalloc_cacheline_aligned(XPC_GP_SIZE, GFP_KERNEL, &part->local_GPs_base); if (part->local_GPs == NULL) { kfree(part->channels); part->channels = NULL; dev_err(xpc_chan, "can't get memory for local get/put " "values\n"); return xpcNoMemory; } memset(part->local_GPs, 0, XPC_GP_SIZE); part->remote_GPs = xpc_kmalloc_cacheline_aligned(XPC_GP_SIZE, GFP_KERNEL, &part->remote_GPs_base); if (part->remote_GPs == NULL) { kfree(part->channels); part->channels = NULL; kfree(part->local_GPs_base); part->local_GPs = NULL; dev_err(xpc_chan, "can't get memory for remote get/put " "values\n"); return xpcNoMemory; } memset(part->remote_GPs, 0, XPC_GP_SIZE); /* allocate all the required open and close args */ part->local_openclose_args = xpc_kmalloc_cacheline_aligned( XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL, &part->local_openclose_args_base); if (part->local_openclose_args == NULL) { kfree(part->channels); part->channels = NULL; kfree(part->local_GPs_base); part->local_GPs = NULL; kfree(part->remote_GPs_base); part->remote_GPs = NULL; dev_err(xpc_chan, "can't get memory for local connect args\n"); return xpcNoMemory; } memset(part->local_openclose_args, 0, XPC_OPENCLOSE_ARGS_SIZE); part->remote_openclose_args = xpc_kmalloc_cacheline_aligned( XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL, &part->remote_openclose_args_base); if (part->remote_openclose_args == NULL) { kfree(part->channels); part->channels = NULL; kfree(part->local_GPs_base); part->local_GPs = NULL; kfree(part->remote_GPs_base); part->remote_GPs = NULL; kfree(part->local_openclose_args_base); part->local_openclose_args = NULL; dev_err(xpc_chan, "can't get memory for remote connect args\n"); return xpcNoMemory; } memset(part->remote_openclose_args, 0, XPC_OPENCLOSE_ARGS_SIZE); xpc_initialize_channels(part, partid); atomic_set(&part->nchannels_active, 0); atomic_set(&part->nchannels_engaged, 0); /* local_IPI_amo were set to 0 by an earlier memset() */ /* Initialize this partitions AMO_t structure */ part->local_IPI_amo_va = xpc_IPI_init(partid); spin_lock_init(&part->IPI_lock); atomic_set(&part->channel_mgr_requests, 1); init_waitqueue_head(&part->channel_mgr_wq); sprintf(part->IPI_owner, "xpc%02d", partid); ret = request_irq(SGI_XPC_NOTIFY, xpc_notify_IRQ_handler, SA_SHIRQ, part->IPI_owner, (void *) (u64) partid); if (ret != 0) { kfree(part->channels); part->channels = NULL; kfree(part->local_GPs_base); part->local_GPs = NULL; kfree(part->remote_GPs_base); part->remote_GPs = NULL; kfree(part->local_openclose_args_base); part->local_openclose_args = NULL; kfree(part->remote_openclose_args_base); part->remote_openclose_args = NULL; dev_err(xpc_chan, "can't register NOTIFY IRQ handler, " "errno=%d\n", -ret); return xpcLackOfResources; } /* Setup a timer to check for dropped IPIs */ timer = &part->dropped_IPI_timer; init_timer(timer); timer->function = (void (*)(unsigned long)) xpc_dropped_IPI_check; timer->data = (unsigned long) part; timer->expires = jiffies + XPC_P_DROPPED_IPI_WAIT; add_timer(timer); /* * With the setting of the partition setup_state to XPC_P_SETUP, we're * declaring that this partition is ready to go. */ part->setup_state = XPC_P_SETUP; /* * Setup the per partition specific variables required by the * remote partition to establish channel connections with us. * * The setting of the magic # indicates that these per partition * specific variables are ready to be used. */ xpc_vars_part[partid].GPs_pa = __pa(part->local_GPs); xpc_vars_part[partid].openclose_args_pa = __pa(part->local_openclose_args); xpc_vars_part[partid].IPI_amo_pa = __pa(part->local_IPI_amo_va); cpuid = raw_smp_processor_id(); /* any CPU in this partition will do */ xpc_vars_part[partid].IPI_nasid = cpuid_to_nasid(cpuid); xpc_vars_part[partid].IPI_phys_cpuid = cpu_physical_id(cpuid); xpc_vars_part[partid].nchannels = part->nchannels; xpc_vars_part[partid].magic = XPC_VP_MAGIC1; return xpcSuccess; } /* * Create a wrapper that hides the underlying mechanism for pulling a cacheline * (or multiple cachelines) from a remote partition. * * src must be a cacheline aligned physical address on the remote partition. * dst must be a cacheline aligned virtual address on this partition. * cnt must be an cacheline sized */ static enum xpc_retval xpc_pull_remote_cachelines(struct xpc_partition *part, void *dst, const void *src, size_t cnt) { bte_result_t bte_ret; DBUG_ON((u64) src != L1_CACHE_ALIGN((u64) src)); DBUG_ON((u64) dst != L1_CACHE_ALIGN((u64) dst)); DBUG_ON(cnt != L1_CACHE_ALIGN(cnt)); if (part->act_state == XPC_P_DEACTIVATING) { return part->reason; } bte_ret = xp_bte_copy((u64) src, (u64) ia64_tpa((u64) dst), (u64) cnt, (BTE_NORMAL | BTE_WACQUIRE), NULL); if (bte_ret == BTE_SUCCESS) { return xpcSuccess; } dev_dbg(xpc_chan, "xp_bte_copy() from partition %d failed, ret=%d\n", XPC_PARTID(part), bte_ret); return xpc_map_bte_errors(bte_ret); } /* * Pull the remote per partititon specific variables from the specified * partition. */ enum xpc_retval xpc_pull_remote_vars_part(struct xpc_partition *part) { u8 buffer[L1_CACHE_BYTES * 2]; struct xpc_vars_part *pulled_entry_cacheline = (struct xpc_vars_part *) L1_CACHE_ALIGN((u64) buffer); struct xpc_vars_part *pulled_entry; u64 remote_entry_cacheline_pa, remote_entry_pa; partid_t partid = XPC_PARTID(part); enum xpc_retval ret; /* pull the cacheline that contains the variables we're interested in */ DBUG_ON(part->remote_vars_part_pa != L1_CACHE_ALIGN(part->remote_vars_part_pa)); DBUG_ON(sizeof(struct xpc_vars_part) != L1_CACHE_BYTES / 2); remote_entry_pa = part->remote_vars_part_pa + sn_partition_id * sizeof(struct xpc_vars_part); remote_entry_cacheline_pa = (remote_entry_pa & ~(L1_CACHE_BYTES - 1)); pulled_entry = (struct xpc_vars_part *) ((u64) pulled_entry_cacheline + (remote_entry_pa & (L1_CACHE_BYTES - 1))); ret = xpc_pull_remote_cachelines(part, pulled_entry_cacheline, (void *) remote_entry_cacheline_pa, L1_CACHE_BYTES); if (ret != xpcSuccess) { dev_dbg(xpc_chan, "failed to pull XPC vars_part from " "partition %d, ret=%d\n", partid, ret); return ret; } /* see if they've been set up yet */ if (pulled_entry->magic != XPC_VP_MAGIC1 && pulled_entry->magic != XPC_VP_MAGIC2) { if (pulled_entry->magic != 0) { dev_dbg(xpc_chan, "partition %d's XPC vars_part for " "partition %d has bad magic value (=0x%lx)\n", partid, sn_partition_id, pulled_entry->magic); return xpcBadMagic; } /* they've not been initialized yet */ return xpcRetry; } if (xpc_vars_part[partid].magic == XPC_VP_MAGIC1) { /* validate the variables */ if (pulled_entry->GPs_pa == 0 || pulled_entry->openclose_args_pa == 0 || pulled_entry->IPI_amo_pa == 0) { dev_err(xpc_chan, "partition %d's XPC vars_part for " "partition %d are not valid\n", partid, sn_partition_id); return xpcInvalidAddress; } /* the variables we imported look to be valid */ part->remote_GPs_pa = pulled_entry->GPs_pa; part->remote_openclose_args_pa = pulled_entry->openclose_args_pa; part->remote_IPI_amo_va = (AMO_t *) __va(pulled_entry->IPI_amo_pa); part->remote_IPI_nasid = pulled_entry->IPI_nasid; part->remote_IPI_phys_cpuid = pulled_entry->IPI_phys_cpuid; if (part->nchannels > pulled_entry->nchannels) { part->nchannels = pulled_entry->nchannels; } /* let the other side know that we've pulled their variables */ xpc_vars_part[partid].magic = XPC_VP_MAGIC2; } if (pulled_entry->magic == XPC_VP_MAGIC1) { return xpcRetry; } return xpcSuccess; } /* * Get the IPI flags and pull the openclose args and/or remote GPs as needed. */ static u64 xpc_get_IPI_flags(struct xpc_partition *part) { unsigned long irq_flags; u64 IPI_amo; enum xpc_retval ret; /* * See if there are any IPI flags to be handled. */ spin_lock_irqsave(&part->IPI_lock, irq_flags); if ((IPI_amo = part->local_IPI_amo) != 0) { part->local_IPI_amo = 0; } spin_unlock_irqrestore(&part->IPI_lock, irq_flags); if (XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(IPI_amo)) { ret = xpc_pull_remote_cachelines(part, part->remote_openclose_args, (void *) part->remote_openclose_args_pa, XPC_OPENCLOSE_ARGS_SIZE); if (ret != xpcSuccess) { XPC_DEACTIVATE_PARTITION(part, ret); dev_dbg(xpc_chan, "failed to pull openclose args from " "partition %d, ret=%d\n", XPC_PARTID(part), ret); /* don't bother processing IPIs anymore */ IPI_amo = 0; } } if (XPC_ANY_MSG_IPI_FLAGS_SET(IPI_amo)) { ret = xpc_pull_remote_cachelines(part, part->remote_GPs, (void *) part->remote_GPs_pa, XPC_GP_SIZE); if (ret != xpcSuccess) { XPC_DEACTIVATE_PARTITION(part, ret); dev_dbg(xpc_chan, "failed to pull GPs from partition " "%d, ret=%d\n", XPC_PARTID(part), ret); /* don't bother processing IPIs anymore */ IPI_amo = 0; } } return IPI_amo; } /* * Allocate the local message queue and the notify queue. */ static enum xpc_retval xpc_allocate_local_msgqueue(struct xpc_channel *ch) { unsigned long irq_flags; int nentries; size_t nbytes; // >>> may want to check for ch->flags & XPC_C_DISCONNECTING between // >>> iterations of the for-loop, bail if set? // >>> should we impose a minumum #of entries? like 4 or 8? for (nentries = ch->local_nentries; nentries > 0; nentries--) { nbytes = nentries * ch->msg_size; ch->local_msgqueue = xpc_kmalloc_cacheline_aligned(nbytes, (GFP_KERNEL | GFP_DMA), &ch->local_msgqueue_base); if (ch->local_msgqueue == NULL) { continue; } memset(ch->local_msgqueue, 0, nbytes); nbytes = nentries * sizeof(struct xpc_notify); ch->notify_queue = kmalloc(nbytes, (GFP_KERNEL | GFP_DMA)); if (ch->notify_queue == NULL) { kfree(ch->local_msgqueue_base); ch->local_msgqueue = NULL; continue; } memset(ch->notify_queue, 0, nbytes); spin_lock_irqsave(&ch->lock, irq_flags); if (nentries < ch->local_nentries) { dev_dbg(xpc_chan, "nentries=%d local_nentries=%d, " "partid=%d, channel=%d\n", nentries, ch->local_nentries, ch->partid, ch->number); ch->local_nentries = nentries; } spin_unlock_irqrestore(&ch->lock, irq_flags); return xpcSuccess; } dev_dbg(xpc_chan, "can't get memory for local message queue and notify " "queue, partid=%d, channel=%d\n", ch->partid, ch->number); return xpcNoMemory; } /* * Allocate the cached remote message queue. */ static enum xpc_retval xpc_allocate_remote_msgqueue(struct xpc_channel *ch) { unsigned long irq_flags; int nentries; size_t nbytes; DBUG_ON(ch->remote_nentries <= 0); // >>> may want to check for ch->flags & XPC_C_DISCONNECTING between // >>> iterations of the for-loop, bail if set? // >>> should we impose a minumum #of entries? like 4 or 8? for (nentries = ch->remote_nentries; nentries > 0; nentries--) { nbytes = nentries * ch->msg_size; ch->remote_msgqueue = xpc_kmalloc_cacheline_aligned(nbytes, (GFP_KERNEL | GFP_DMA), &ch->remote_msgqueue_base); if (ch->remote_msgqueue == NULL) { continue; } memset(ch->remote_msgqueue, 0, nbytes); spin_lock_irqsave(&ch->lock, irq_flags); if (nentries < ch->remote_nentries) { dev_dbg(xpc_chan, "nentries=%d remote_nentries=%d, " "partid=%d, channel=%d\n", nentries, ch->remote_nentries, ch->partid, ch->number); ch->remote_nentries = nentries; } spin_unlock_irqrestore(&ch->lock, irq_flags); return xpcSuccess; } dev_dbg(xpc_chan, "can't get memory for cached remote message queue, " "partid=%d, channel=%d\n", ch->partid, ch->number); return xpcNoMemory; } /* * Allocate message queues and other stuff associated with a channel. * * Note: Assumes all of the channel sizes are filled in. */ static enum xpc_retval xpc_allocate_msgqueues(struct xpc_channel *ch) { unsigned long irq_flags; int i; enum xpc_retval ret; DBUG_ON(ch->flags & XPC_C_SETUP); if ((ret = xpc_allocate_local_msgqueue(ch)) != xpcSuccess) { return ret; } if ((ret = xpc_allocate_remote_msgqueue(ch)) != xpcSuccess) { kfree(ch->local_msgqueue_base); ch->local_msgqueue = NULL; kfree(ch->notify_queue); ch->notify_queue = NULL; return ret; } for (i = 0; i < ch->local_nentries; i++) { /* use a semaphore as an event wait queue */ sema_init(&ch->notify_queue[i].sema, 0); } spin_lock_irqsave(&ch->lock, irq_flags); ch->flags |= XPC_C_SETUP; spin_unlock_irqrestore(&ch->lock, irq_flags); return xpcSuccess; } /* * Process a connect message from a remote partition. * * Note: xpc_process_connect() is expecting to be called with the * spin_lock_irqsave held and will leave it locked upon return. */ static void xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags) { enum xpc_retval ret; DBUG_ON(!spin_is_locked(&ch->lock)); if (!(ch->flags & XPC_C_OPENREQUEST) || !(ch->flags & XPC_C_ROPENREQUEST)) { /* nothing more to do for now */ return; } DBUG_ON(!(ch->flags & XPC_C_CONNECTING)); if (!(ch->flags & XPC_C_SETUP)) { spin_unlock_irqrestore(&ch->lock, *irq_flags); ret = xpc_allocate_msgqueues(ch); spin_lock_irqsave(&ch->lock, *irq_flags); if (ret != xpcSuccess) { XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags); } if (ch->flags & (XPC_C_CONNECTED | XPC_C_DISCONNECTING)) { return; } DBUG_ON(!(ch->flags & XPC_C_SETUP)); DBUG_ON(ch->local_msgqueue == NULL); DBUG_ON(ch->remote_msgqueue == NULL); } if (!(ch->flags & XPC_C_OPENREPLY)) { ch->flags |= XPC_C_OPENREPLY; xpc_IPI_send_openreply(ch, irq_flags); } if (!(ch->flags & XPC_C_ROPENREPLY)) { return; } DBUG_ON(ch->remote_msgqueue_pa == 0); ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP); /* clear all else */ dev_info(xpc_chan, "channel %d to partition %d connected\n", ch->number, ch->partid); spin_unlock_irqrestore(&ch->lock, *irq_flags); xpc_create_kthreads(ch, 1); spin_lock_irqsave(&ch->lock, *irq_flags); } /* * Notify those who wanted to be notified upon delivery of their message. */ static void xpc_notify_senders(struct xpc_channel *ch, enum xpc_retval reason, s64 put) { struct xpc_notify *notify; u8 notify_type; s64 get = ch->w_remote_GP.get - 1; while (++get < put && atomic_read(&ch->n_to_notify) > 0) { notify = &ch->notify_queue[get % ch->local_nentries]; /* * See if the notify entry indicates it was associated with * a message who's sender wants to be notified. It is possible * that it is, but someone else is doing or has done the * notification. */ notify_type = notify->type; if (notify_type == 0 || cmpxchg(¬ify->type, notify_type, 0) != notify_type) { continue; } DBUG_ON(notify_type != XPC_N_CALL); atomic_dec(&ch->n_to_notify); if (notify->func != NULL) { dev_dbg(xpc_chan, "notify->func() called, notify=0x%p, " "msg_number=%ld, partid=%d, channel=%d\n", (void *) notify, get, ch->partid, ch->number); notify->func(reason, ch->partid, ch->number, notify->key); dev_dbg(xpc_chan, "notify->func() returned, " "notify=0x%p, msg_number=%ld, partid=%d, " "channel=%d\n", (void *) notify, get, ch->partid, ch->number); } } } /* * Free up message queues and other stuff that were allocated for the specified * channel. * * Note: ch->reason and ch->reason_line are left set for debugging purposes, * they're cleared when XPC_C_DISCONNECTED is cleared. */ static void xpc_free_msgqueues(struct xpc_channel *ch) { DBUG_ON(!spin_is_locked(&ch->lock)); DBUG_ON(atomic_read(&ch->n_to_notify) != 0); ch->remote_msgqueue_pa = 0; ch->func = NULL; ch->key = NULL; ch->msg_size = 0; ch->local_nentries = 0; ch->remote_nentries = 0; ch->kthreads_assigned_limit = 0; ch->kthreads_idle_limit = 0; ch->local_GP->get = 0; ch->local_GP->put = 0; ch->remote_GP.get = 0; ch->remote_GP.put = 0; ch->w_local_GP.get = 0; ch->w_local_GP.put = 0; ch->w_remote_GP.get = 0; ch->w_remote_GP.put = 0; ch->next_msg_to_pull = 0; if (ch->flags & XPC_C_SETUP) { ch->flags &= ~XPC_C_SETUP; dev_dbg(xpc_chan, "ch->flags=0x%x, partid=%d, channel=%d\n", ch->flags, ch->partid, ch->number); kfree(ch->local_msgqueue_base); ch->local_msgqueue = NULL; kfree(ch->remote_msgqueue_base); ch->remote_msgqueue = NULL; kfree(ch->notify_queue); ch->notify_queue = NULL; } } /* * spin_lock_irqsave() is expected to be held on entry. */ static void xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags) { struct xpc_partition *part = &xpc_partitions[ch->partid]; u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED); DBUG_ON(!spin_is_locked(&ch->lock)); if (!(ch->flags & XPC_C_DISCONNECTING)) { return; } DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST)); /* make sure all activity has settled down first */ if (atomic_read(&ch->references) > 0) { return; } DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0); if (part->act_state == XPC_P_DEACTIVATING) { /* can't proceed until the other side disengages from us */ if (xpc_partition_engaged(1UL << ch->partid)) { return; } } else { /* as long as the other side is up do the full protocol */ if (!(ch->flags & XPC_C_RCLOSEREQUEST)) { return; } if (!(ch->flags & XPC_C_CLOSEREPLY)) { ch->flags |= XPC_C_CLOSEREPLY; xpc_IPI_send_closereply(ch, irq_flags); } if (!(ch->flags & XPC_C_RCLOSEREPLY)) { return; } } /* wake those waiting for notify completion */ if (atomic_read(&ch->n_to_notify) > 0) { /* >>> we do callout while holding ch->lock */ xpc_notify_senders(ch, ch->reason, ch->w_local_GP.put); } /* both sides are disconnected now */ /* it's now safe to free the channel's message queues */ xpc_free_msgqueues(ch); /* mark disconnected, clear all other flags except XPC_C_WDISCONNECT */ ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT)); atomic_dec(&part->nchannels_active); if (channel_was_connected) { dev_info(xpc_chan, "channel %d to partition %d disconnected, " "reason=%d\n", ch->number, ch->partid, ch->reason); } /* wake the thread that is waiting for this channel to disconnect */ if (ch->flags & XPC_C_WDISCONNECT) { spin_unlock_irqrestore(&ch->lock, *irq_flags); up(&ch->wdisconnect_sema); spin_lock_irqsave(&ch->lock, *irq_flags); } } /* * Process a change in the channel's remote connection state. */ static void xpc_process_openclose_IPI(struct xpc_partition *part, int ch_number, u8 IPI_flags) { unsigned long irq_flags; struct xpc_openclose_args *args = &part->remote_openclose_args[ch_number]; struct xpc_channel *ch = &part->channels[ch_number]; enum xpc_retval reason; spin_lock_irqsave(&ch->lock, irq_flags); if (IPI_flags & XPC_IPI_CLOSEREQUEST) { dev_dbg(xpc_chan, "XPC_IPI_CLOSEREQUEST (reason=%d) received " "from partid=%d, channel=%d\n", args->reason, ch->partid, ch->number); /* * If RCLOSEREQUEST is set, we're probably waiting for * RCLOSEREPLY. We should find it and a ROPENREQUEST packed * with this RCLOSEREQUEST in the IPI_flags. */ if (ch->flags & XPC_C_RCLOSEREQUEST) { DBUG_ON(!(ch->flags & XPC_C_DISCONNECTING)); DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST)); DBUG_ON(!(ch->flags & XPC_C_CLOSEREPLY)); DBUG_ON(ch->flags & XPC_C_RCLOSEREPLY); DBUG_ON(!(IPI_flags & XPC_IPI_CLOSEREPLY)); IPI_flags &= ~XPC_IPI_CLOSEREPLY; ch->flags |= XPC_C_RCLOSEREPLY; /* both sides have finished disconnecting */ xpc_process_disconnect(ch, &irq_flags); } if (ch->flags & XPC_C_DISCONNECTED) { // >>> explain this section if (!(IPI_flags & XPC_IPI_OPENREQUEST)) { DBUG_ON(part->act_state != XPC_P_DEACTIVATING); spin_unlock_irqrestore(&ch->lock, irq_flags); return; } XPC_SET_REASON(ch, 0, 0); ch->flags &= ~XPC_C_DISCONNECTED; atomic_inc(&part->nchannels_active); ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST); } IPI_flags &= ~(XPC_IPI_OPENREQUEST | XPC_IPI_OPENREPLY); /* * The meaningful CLOSEREQUEST connection state fields are: * reason = reason connection is to be closed */ ch->flags |= XPC_C_RCLOSEREQUEST; if (!(ch->flags & XPC_C_DISCONNECTING)) { reason = args->reason; if (reason <= xpcSuccess || reason > xpcUnknownReason) { reason = xpcUnknownReason; } else if (reason == xpcUnregistering) { reason = xpcOtherUnregistering; } XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags); } else { xpc_process_disconnect(ch, &irq_flags); } } if (IPI_flags & XPC_IPI_CLOSEREPLY) { dev_dbg(xpc_chan, "XPC_IPI_CLOSEREPLY received from partid=%d," " channel=%d\n", ch->partid, ch->number); if (ch->flags & XPC_C_DISCONNECTED) { DBUG_ON(part->act_state != XPC_P_DEACTIVATING); spin_unlock_irqrestore(&ch->lock, irq_flags); return; } DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST)); DBUG_ON(!(ch->flags & XPC_C_RCLOSEREQUEST)); ch->flags |= XPC_C_RCLOSEREPLY; if (ch->flags & XPC_C_CLOSEREPLY) { /* both sides have finished disconnecting */ xpc_process_disconnect(ch, &irq_flags); } } if (IPI_flags & XPC_IPI_OPENREQUEST) { dev_dbg(xpc_chan, "XPC_IPI_OPENREQUEST (msg_size=%d, " "local_nentries=%d) received from partid=%d, " "channel=%d\n", args->msg_size, args->local_nentries, ch->partid, ch->number); if ((ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) || part->act_state == XPC_P_DEACTIVATING) { spin_unlock_irqrestore(&ch->lock, irq_flags); return; } DBUG_ON(!(ch->flags & (XPC_C_DISCONNECTED | XPC_C_OPENREQUEST))); DBUG_ON(ch->flags & (XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY | XPC_C_OPENREPLY | XPC_C_CONNECTED)); /* * The meaningful OPENREQUEST connection state fields are: * msg_size = size of channel's messages in bytes * local_nentries = remote partition's local_nentries */ DBUG_ON(args->msg_size == 0); DBUG_ON(args->local_nentries == 0); ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING); ch->remote_nentries = args->local_nentries; if (ch->flags & XPC_C_OPENREQUEST) { if (args->msg_size != ch->msg_size) { XPC_DISCONNECT_CHANNEL(ch, xpcUnequalMsgSizes, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); return; } } else { ch->msg_size = args->msg_size; XPC_SET_REASON(ch, 0, 0); ch->flags &= ~XPC_C_DISCONNECTED; atomic_inc(&part->nchannels_active); } xpc_process_connect(ch, &irq_flags); } if (IPI_flags & XPC_IPI_OPENREPLY) { dev_dbg(xpc_chan, "XPC_IPI_OPENREPLY (local_msgqueue_pa=0x%lx, " "local_nentries=%d, remote_nentries=%d) received from " "partid=%d, channel=%d\n", args->local_msgqueue_pa, args->local_nentries, args->remote_nentries, ch->partid, ch->number); if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED)) { spin_unlock_irqrestore(&ch->lock, irq_flags); return; } DBUG_ON(!(ch->flags & XPC_C_OPENREQUEST)); DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST)); DBUG_ON(ch->flags & XPC_C_CONNECTED); /* * The meaningful OPENREPLY connection state fields are: * local_msgqueue_pa = physical address of remote * partition's local_msgqueue * local_nentries = remote partition's local_nentries * remote_nentries = remote partition's remote_nentries */ DBUG_ON(args->local_msgqueue_pa == 0); DBUG_ON(args->local_nentries == 0); DBUG_ON(args->remote_nentries == 0); ch->flags |= XPC_C_ROPENREPLY; ch->remote_msgqueue_pa = args->local_msgqueue_pa; if (args->local_nentries < ch->remote_nentries) { dev_dbg(xpc_chan, "XPC_IPI_OPENREPLY: new " "remote_nentries=%d, old remote_nentries=%d, " "partid=%d, channel=%d\n", args->local_nentries, ch->remote_nentries, ch->partid, ch->number); ch->remote_nentries = args->local_nentries; } if (args->remote_nentries < ch->local_nentries) { dev_dbg(xpc_chan, "XPC_IPI_OPENREPLY: new " "local_nentries=%d, old local_nentries=%d, " "partid=%d, channel=%d\n", args->remote_nentries, ch->local_nentries, ch->partid, ch->number); ch->local_nentries = args->remote_nentries; } xpc_process_connect(ch, &irq_flags); } spin_unlock_irqrestore(&ch->lock, irq_flags); } /* * Attempt to establish a channel connection to a remote partition. */ static enum xpc_retval xpc_connect_channel(struct xpc_channel *ch) { unsigned long irq_flags; struct xpc_registration *registration = &xpc_registrations[ch->number]; if (down_interruptible(®istration->sema) != 0) { return xpcInterrupted; } if (!XPC_CHANNEL_REGISTERED(ch->number)) { up(®istration->sema); return xpcUnregistered; } spin_lock_irqsave(&ch->lock, irq_flags); DBUG_ON(ch->flags & XPC_C_CONNECTED); DBUG_ON(ch->flags & XPC_C_OPENREQUEST); if (ch->flags & XPC_C_DISCONNECTING) { spin_unlock_irqrestore(&ch->lock, irq_flags); up(®istration->sema); return ch->reason; } /* add info from the channel connect registration to the channel */ ch->kthreads_assigned_limit = registration->assigned_limit; ch->kthreads_idle_limit = registration->idle_limit; DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0); DBUG_ON(atomic_read(&ch->kthreads_idle) != 0); DBUG_ON(atomic_read(&ch->kthreads_active) != 0); ch->func = registration->func; DBUG_ON(registration->func == NULL); ch->key = registration->key; ch->local_nentries = registration->nentries; if (ch->flags & XPC_C_ROPENREQUEST) { if (registration->msg_size != ch->msg_size) { /* the local and remote sides aren't the same */ /* * Because XPC_DISCONNECT_CHANNEL() can block we're * forced to up the registration sema before we unlock * the channel lock. But that's okay here because we're * done with the part that required the registration * sema. XPC_DISCONNECT_CHANNEL() requires that the * channel lock be locked and will unlock and relock * the channel lock as needed. */ up(®istration->sema); XPC_DISCONNECT_CHANNEL(ch, xpcUnequalMsgSizes, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); return xpcUnequalMsgSizes; } } else { ch->msg_size = registration->msg_size; XPC_SET_REASON(ch, 0, 0); ch->flags &= ~XPC_C_DISCONNECTED; atomic_inc(&xpc_partitions[ch->partid].nchannels_active); } up(®istration->sema); /* initiate the connection */ ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING); xpc_IPI_send_openrequest(ch, &irq_flags); xpc_process_connect(ch, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); return xpcSuccess; } /* * Clear some of the msg flags in the local message queue. */ static inline void xpc_clear_local_msgqueue_flags(struct xpc_channel *ch) { struct xpc_msg *msg; s64 get; get = ch->w_remote_GP.get; do { msg = (struct xpc_msg *) ((u64) ch->local_msgqueue + (get % ch->local_nentries) * ch->msg_size); msg->flags = 0; } while (++get < (volatile s64) ch->remote_GP.get); } /* * Clear some of the msg flags in the remote message queue. */ static inline void xpc_clear_remote_msgqueue_flags(struct xpc_channel *ch) { struct xpc_msg *msg; s64 put; put = ch->w_remote_GP.put; do { msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue + (put % ch->remote_nentries) * ch->msg_size); msg->flags = 0; } while (++put < (volatile s64) ch->remote_GP.put); } static void xpc_process_msg_IPI(struct xpc_partition *part, int ch_number) { struct xpc_channel *ch = &part->channels[ch_number]; int nmsgs_sent; ch->remote_GP = part->remote_GPs[ch_number]; /* See what, if anything, has changed for each connected channel */ xpc_msgqueue_ref(ch); if (ch->w_remote_GP.get == ch->remote_GP.get && ch->w_remote_GP.put == ch->remote_GP.put) { /* nothing changed since GPs were last pulled */ xpc_msgqueue_deref(ch); return; } if (!(ch->flags & XPC_C_CONNECTED)){ xpc_msgqueue_deref(ch); return; } /* * First check to see if messages recently sent by us have been * received by the other side. (The remote GET value will have * changed since we last looked at it.) */ if (ch->w_remote_GP.get != ch->remote_GP.get) { /* * We need to notify any senders that want to be notified * that their sent messages have been received by their * intended recipients. We need to do this before updating * w_remote_GP.get so that we don't allocate the same message * queue entries prematurely (see xpc_allocate_msg()). */ if (atomic_read(&ch->n_to_notify) > 0) { /* * Notify senders that messages sent have been * received and delivered by the other side. */ xpc_notify_senders(ch, xpcMsgDelivered, ch->remote_GP.get); } /* * Clear msg->flags in previously sent messages, so that * they're ready for xpc_allocate_msg(). */ xpc_clear_local_msgqueue_flags(ch); ch->w_remote_GP.get = ch->remote_GP.get; dev_dbg(xpc_chan, "w_remote_GP.get changed to %ld, partid=%d, " "channel=%d\n", ch->w_remote_GP.get, ch->partid, ch->number); /* * If anyone was waiting for message queue entries to become * available, wake them up. */ if (atomic_read(&ch->n_on_msg_allocate_wq) > 0) { wake_up(&ch->msg_allocate_wq); } } /* * Now check for newly sent messages by the other side. (The remote * PUT value will have changed since we last looked at it.) */ if (ch->w_remote_GP.put != ch->remote_GP.put) { /* * Clear msg->flags in previously received messages, so that * they're ready for xpc_get_deliverable_msg(). */ xpc_clear_remote_msgqueue_flags(ch); ch->w_remote_GP.put = ch->remote_GP.put; dev_dbg(xpc_chan, "w_remote_GP.put changed to %ld, partid=%d, " "channel=%d\n", ch->w_remote_GP.put, ch->partid, ch->number); nmsgs_sent = ch->w_remote_GP.put - ch->w_local_GP.get; if (nmsgs_sent > 0) { dev_dbg(xpc_chan, "msgs waiting to be copied and " "delivered=%d, partid=%d, channel=%d\n", nmsgs_sent, ch->partid, ch->number); if (ch->flags & XPC_C_CONNECTCALLOUT) { xpc_activate_kthreads(ch, nmsgs_sent); } } } xpc_msgqueue_deref(ch); } void xpc_process_channel_activity(struct xpc_partition *part) { unsigned long irq_flags; u64 IPI_amo, IPI_flags; struct xpc_channel *ch; int ch_number; u32 ch_flags; IPI_amo = xpc_get_IPI_flags(part); /* * Initiate channel connections for registered channels. * * For each connected channel that has pending messages activate idle * kthreads and/or create new kthreads as needed. */ for (ch_number = 0; ch_number < part->nchannels; ch_number++) { ch = &part->channels[ch_number]; /* * Process any open or close related IPI flags, and then deal * with connecting or disconnecting the channel as required. */ IPI_flags = XPC_GET_IPI_FLAGS(IPI_amo, ch_number); if (XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(IPI_flags)) { xpc_process_openclose_IPI(part, ch_number, IPI_flags); } ch_flags = ch->flags; /* need an atomic snapshot of flags */ if (ch_flags & XPC_C_DISCONNECTING) { spin_lock_irqsave(&ch->lock, irq_flags); xpc_process_disconnect(ch, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); continue; } if (part->act_state == XPC_P_DEACTIVATING) { continue; } if (!(ch_flags & XPC_C_CONNECTED)) { if (!(ch_flags & XPC_C_OPENREQUEST)) { DBUG_ON(ch_flags & XPC_C_SETUP); (void) xpc_connect_channel(ch); } else { spin_lock_irqsave(&ch->lock, irq_flags); xpc_process_connect(ch, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); } continue; } /* * Process any message related IPI flags, this may involve the * activation of kthreads to deliver any pending messages sent * from the other partition. */ if (XPC_ANY_MSG_IPI_FLAGS_SET(IPI_flags)) { xpc_process_msg_IPI(part, ch_number); } } } /* * XPC's heartbeat code calls this function to inform XPC that a partition is * going down. XPC responds by tearing down the XPartition Communication * infrastructure used for the just downed partition. * * XPC's heartbeat code will never call this function and xpc_partition_up() * at the same time. Nor will it ever make multiple calls to either function * at the same time. */ void xpc_partition_going_down(struct xpc_partition *part, enum xpc_retval reason) { unsigned long irq_flags; int ch_number; struct xpc_channel *ch; dev_dbg(xpc_chan, "deactivating partition %d, reason=%d\n", XPC_PARTID(part), reason); if (!xpc_part_ref(part)) { /* infrastructure for this partition isn't currently set up */ return; } /* disconnect channels associated with the partition going down */ for (ch_number = 0; ch_number < part->nchannels; ch_number++) { ch = &part->channels[ch_number]; xpc_msgqueue_ref(ch); spin_lock_irqsave(&ch->lock, irq_flags); XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags); spin_unlock_irqrestore(&ch->lock, irq_flags); xpc_msgqueue_deref(ch); } xpc_wakeup_channel_mgr(part); xpc_part_deref(part); } /* * Teardown the infrastructure necessary to support XPartition Communication * between the specified remote partition and the local one. */ void xpc_teardown_infrastructure(struct xpc_partition *part) { partid_t partid = XPC_PARTID(part); /* * We start off by making this partition inaccessible to local * processes by marking it as no longer setup. Then we make it * inaccessible to remote processes by clearing the XPC per partition * specific variable's magic # (which indicates that these variables * are no longer valid) and by ignoring all XPC notify IPIs sent to * this partition. */ DBUG_ON(atomic_read(&part->nchannels_engaged) != 0); DBUG_ON(atomic_read(&part->nchannels_active) != 0); DBUG_ON(part->setup_state != XPC_P_SETUP); part->setup_state = XPC_P_WTEARDOWN; xpc_vars_part[partid].magic = 0; free_irq(SGI_XPC_NOTIFY, (void *) (u64) partid); /* * Before proceding with the teardown we have to wait until all * existing references cease. */ wait_event(part->teardown_wq, (atomic_read(&part->references) == 0)); /* now we can begin tearing down the infrastructure */ part->setup_state = XPC_P_TORNDOWN; /* in case we've still got outstanding timers registered... */ del_timer_sync(&part->dropped_IPI_timer); kfree(part->remote_openclose_args_base); part->remote_openclose_args = NULL; kfree(part->local_openclose_args_base); part->local_openclose_args = NULL; kfree(part->remote_GPs_base); part->remote_GPs = NULL; kfree(part->local_GPs_base); part->local_GPs = NULL; kfree(part->channels); part->channels = NULL; part->local_IPI_amo_va = NULL; } /* * Called by XP at the time of channel connection registration to cause * XPC to establish connections to all currently active partitions. */ void xpc_initiate_connect(int ch_number) { partid_t partid; struct xpc_partition *part; struct xpc_channel *ch; DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS); for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) { part = &xpc_partitions[partid]; if (xpc_part_ref(part)) { ch = &part->channels[ch_number]; if (!(ch->flags & XPC_C_DISCONNECTING)) { DBUG_ON(ch->flags & XPC_C_OPENREQUEST); DBUG_ON(ch->flags & XPC_C_CONNECTED); DBUG_ON(ch->flags & XPC_C_SETUP); /* * Initiate the establishment of a connection * on the newly registered channel to the * remote partition. */ xpc_wakeup_channel_mgr(part); } xpc_part_deref(part); } } } void xpc_connected_callout(struct xpc_channel *ch) { unsigned long irq_flags; /* let the registerer know that a connection has been established */ if (ch->func != NULL) { dev_dbg(xpc_chan, "ch->func() called, reason=xpcConnected, " "partid=%d, channel=%d\n", ch->partid, ch->number); ch->func(xpcConnected, ch->partid, ch->number, (void *) (u64) ch->local_nentries, ch->key); dev_dbg(xpc_chan, "ch->func() returned, reason=xpcConnected, " "partid=%d, channel=%d\n", ch->partid, ch->number); } spin_lock_irqsave(&ch->lock, irq_flags); ch->flags |= XPC_C_CONNECTCALLOUT; spin_unlock_irqrestore(&ch->lock, irq_flags); } /* * Called by XP at the time of channel connection unregistration to cause * XPC to teardown all current connections for the specified channel. * * Before returning xpc_initiate_disconnect() will wait until all connections * on the specified channel have been closed/torndown. So the caller can be * assured that they will not be receiving any more callouts from XPC to the * function they registered via xpc_connect(). * * Arguments: * * ch_number - channel # to unregister. */ void xpc_initiate_disconnect(int ch_number) { unsigned long irq_flags; partid_t partid; struct xpc_partition *part; struct xpc_channel *ch; DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS); /* initiate the channel disconnect for every active partition */ for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) { part = &xpc_partitions[partid]; if (xpc_part_ref(part)) { ch = &part->channels[ch_number]; xpc_msgqueue_ref(ch); spin_lock_irqsave(&ch->lock, irq_flags); if (!(ch->flags & XPC_C_DISCONNECTED)) { ch->flags |= XPC_C_WDISCONNECT; XPC_DISCONNECT_CHANNEL(ch, xpcUnregistering, &irq_flags); } spin_unlock_irqrestore(&ch->lock, irq_flags); xpc_msgqueue_deref(ch); xpc_part_deref(part); } } xpc_disconnect_wait(ch_number); } /* * To disconnect a channel, and reflect it back to all who may be waiting. * * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by * xpc_disconnect_wait(). * * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN. */ void xpc_disconnect_channel(const int line, struct xpc_channel *ch, enum xpc_retval reason, unsigned long *irq_flags) { u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED); DBUG_ON(!spin_is_locked(&ch->lock)); if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED)) { return; } DBUG_ON(!(ch->flags & (XPC_C_CONNECTING | XPC_C_CONNECTED))); dev_dbg(xpc_chan, "reason=%d, line=%d, partid=%d, channel=%d\n", reason, line, ch->partid, ch->number); XPC_SET_REASON(ch, reason, line); ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING); /* some of these may not have been set */ ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY | XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY | XPC_C_CONNECTING | XPC_C_CONNECTED); xpc_IPI_send_closerequest(ch, irq_flags); if (channel_was_connected) { ch->flags |= XPC_C_WASCONNECTED; } spin_unlock_irqrestore(&ch->lock, *irq_flags); /* wake all idle kthreads so they can exit */ if (atomic_read(&ch->kthreads_idle) > 0) { wake_up_all(&ch->idle_wq); } /* wake those waiting to allocate an entry from the local msg queue */ if (atomic_read(&ch->n_on_msg_allocate_wq) > 0) { wake_up(&ch->msg_allocate_wq); } spin_lock_irqsave(&ch->lock, *irq_flags); } void xpc_disconnecting_callout(struct xpc_channel *ch) { /* * Let the channel's registerer know that the channel is being * disconnected. We don't want to do this if the registerer was never * informed of a connection being made. */ if (ch->func != NULL) { dev_dbg(xpc_chan, "ch->func() called, reason=xpcDisconnecting," " partid=%d, channel=%d\n", ch->partid, ch->number); ch->func(xpcDisconnecting, ch->partid, ch->number, NULL, ch->key); dev_dbg(xpc_chan, "ch->func() returned, reason=" "xpcDisconnecting, partid=%d, channel=%d\n", ch->partid, ch->number); } } /* * Wait for a message entry to become available for the specified channel, * but don't wait any longer than 1 jiffy. */ static enum xpc_retval xpc_allocate_msg_wait(struct xpc_channel *ch) { enum xpc_retval ret; if (ch->flags & XPC_C_DISCONNECTING) { DBUG_ON(ch->reason == xpcInterrupted); // >>> Is this true? return ch->reason; } atomic_inc(&ch->n_on_msg_allocate_wq); ret = interruptible_sleep_on_timeout(&ch->msg_allocate_wq, 1); atomic_dec(&ch->n_on_msg_allocate_wq); if (ch->flags & XPC_C_DISCONNECTING) { ret = ch->reason; DBUG_ON(ch->reason == xpcInterrupted); // >>> Is this true? } else if (ret == 0) { ret = xpcTimeout; } else { ret = xpcInterrupted; } return ret; } /* * Allocate an entry for a message from the message queue associated with the * specified channel. */ static enum xpc_retval xpc_allocate_msg(struct xpc_channel *ch, u32 flags, struct xpc_msg **address_of_msg) { struct xpc_msg *msg; enum xpc_retval ret; s64 put; /* this reference will be dropped in xpc_send_msg() */ xpc_msgqueue_ref(ch); if (ch->flags & XPC_C_DISCONNECTING) { xpc_msgqueue_deref(ch); return ch->reason; } if (!(ch->flags & XPC_C_CONNECTED)) { xpc_msgqueue_deref(ch); return xpcNotConnected; } /* * Get the next available message entry from the local message queue. * If none are available, we'll make sure that we grab the latest * GP values. */ ret = xpcTimeout; while (1) { put = (volatile s64) ch->w_local_GP.put; if (put - (volatile s64) ch->w_remote_GP.get < ch->local_nentries) { /* There are available message entries. We need to try * to secure one for ourselves. We'll do this by trying * to increment w_local_GP.put as long as someone else * doesn't beat us to it. If they do, we'll have to * try again. */ if (cmpxchg(&ch->w_local_GP.put, put, put + 1) == put) { /* we got the entry referenced by put */ break; } continue; /* try again */ } /* * There aren't any available msg entries at this time. * * In waiting for a message entry to become available, * we set a timeout in case the other side is not * sending completion IPIs. This lets us fake an IPI * that will cause the IPI handler to fetch the latest * GP values as if an IPI was sent by the other side. */ if (ret == xpcTimeout) { xpc_IPI_send_local_msgrequest(ch); } if (flags & XPC_NOWAIT) { xpc_msgqueue_deref(ch); return xpcNoWait; } ret = xpc_allocate_msg_wait(ch); if (ret != xpcInterrupted && ret != xpcTimeout) { xpc_msgqueue_deref(ch); return ret; } } /* get the message's address and initialize it */ msg = (struct xpc_msg *) ((u64) ch->local_msgqueue + (put % ch->local_nentries) * ch->msg_size); DBUG_ON(msg->flags != 0); msg->number = put; dev_dbg(xpc_chan, "w_local_GP.put changed to %ld; msg=0x%p, " "msg_number=%ld, partid=%d, channel=%d\n", put + 1, (void *) msg, msg->number, ch->partid, ch->number); *address_of_msg = msg; return xpcSuccess; } /* * Allocate an entry for a message from the message queue associated with the * specified channel. NOTE that this routine can sleep waiting for a message * entry to become available. To not sleep, pass in the XPC_NOWAIT flag. * * Arguments: * * partid - ID of partition to which the channel is connected. * ch_number - channel #. * flags - see xpc.h for valid flags. * payload - address of the allocated payload area pointer (filled in on * return) in which the user-defined message is constructed. */ enum xpc_retval xpc_initiate_allocate(partid_t partid, int ch_number, u32 flags, void **payload) { struct xpc_partition *part = &xpc_partitions[partid]; enum xpc_retval ret = xpcUnknownReason; struct xpc_msg *msg; DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS); DBUG_ON(ch_number < 0 || ch_number >= part->nchannels); *payload = NULL; if (xpc_part_ref(part)) { ret = xpc_allocate_msg(&part->channels[ch_number], flags, &msg); xpc_part_deref(part); if (msg != NULL) { *payload = &msg->payload; } } return ret; } /* * Now we actually send the messages that are ready to be sent by advancing * the local message queue's Put value and then send an IPI to the recipient * partition. */ static void xpc_send_msgs(struct xpc_channel *ch, s64 initial_put) { struct xpc_msg *msg; s64 put = initial_put + 1; int send_IPI = 0; while (1) { while (1) { if (put == (volatile s64) ch->w_local_GP.put) { break; } msg = (struct xpc_msg *) ((u64) ch->local_msgqueue + (put % ch->local_nentries) * ch->msg_size); if (!(msg->flags & XPC_M_READY)) { break; } put++; } if (put == initial_put) { /* nothing's changed */ break; } if (cmpxchg_rel(&ch->local_GP->put, initial_put, put) != initial_put) { /* someone else beat us to it */ DBUG_ON((volatile s64) ch->local_GP->put < initial_put); break; } /* we just set the new value of local_GP->put */ dev_dbg(xpc_chan, "local_GP->put changed to %ld, partid=%d, " "channel=%d\n", put, ch->partid, ch->number); send_IPI = 1; /* * We need to ensure that the message referenced by * local_GP->put is not XPC_M_READY or that local_GP->put * equals w_local_GP.put, so we'll go have a look. */ initial_put = put; } if (send_IPI) { xpc_IPI_send_msgrequest(ch); } } /* * Common code that does the actual sending of the message by advancing the * local message queue's Put value and sends an IPI to the partition the * message is being sent to. */ static enum xpc_retval xpc_send_msg(struct xpc_channel *ch, struct xpc_msg *msg, u8 notify_type, xpc_notify_func func, void *key) { enum xpc_retval ret = xpcSuccess; struct xpc_notify *notify = notify; s64 put, msg_number = msg->number; DBUG_ON(notify_type == XPC_N_CALL && func == NULL); DBUG_ON((((u64) msg - (u64) ch->local_msgqueue) / ch->msg_size) != msg_number % ch->local_nentries); DBUG_ON(msg->flags & XPC_M_READY); if (ch->flags & XPC_C_DISCONNECTING) { /* drop the reference grabbed in xpc_allocate_msg() */ xpc_msgqueue_deref(ch); return ch->reason; } if (notify_type != 0) { /* * Tell the remote side to send an ACK interrupt when the * message has been delivered. */ msg->flags |= XPC_M_INTERRUPT; atomic_inc(&ch->n_to_notify); notify = &ch->notify_queue[msg_number % ch->local_nentries]; notify->func = func; notify->key = key; notify->type = notify_type; // >>> is a mb() needed here? if (ch->flags & XPC_C_DISCONNECTING) { /* * An error occurred between our last error check and * this one. We will try to clear the type field from * the notify entry. If we succeed then * xpc_disconnect_channel() didn't already process * the notify entry. */ if (cmpxchg(¬ify->type, notify_type, 0) == notify_type) { atomic_dec(&ch->n_to_notify); ret = ch->reason; } /* drop the reference grabbed in xpc_allocate_msg() */ xpc_msgqueue_deref(ch); return ret; } } msg->flags |= XPC_M_READY; /* * The preceding store of msg->flags must occur before the following * load of ch->local_GP->put. */ mb(); /* see if the message is next in line to be sent, if so send it */ put = ch->local_GP->put; if (put == msg_number) { xpc_send_msgs(ch, put); } /* drop the reference grabbed in xpc_allocate_msg() */ xpc_msgqueue_deref(ch); return ret; } /* * Send a message previously allocated using xpc_initiate_allocate() on the * specified channel connected to the specified partition. * * This routine will not wait for the message to be received, nor will * notification be given when it does happen. Once this routine has returned * the message entry allocated via xpc_initiate_allocate() is no longer * accessable to the caller. * * This routine, although called by users, does not call xpc_part_ref() to * ensure that the partition infrastructure is in place. It relies on the * fact that we called xpc_msgqueue_ref() in xpc_allocate_msg(). * * Arguments: * * partid - ID of partition to which the channel is connected. * ch_number - channel # to send message on. * payload - pointer to the payload area allocated via * xpc_initiate_allocate(). */ enum xpc_retval xpc_initiate_send(partid_t partid, int ch_number, void *payload) { struct xpc_partition *part = &xpc_partitions[partid]; struct xpc_msg *msg = XPC_MSG_ADDRESS(payload); enum xpc_retval ret; dev_dbg(xpc_chan, "msg=0x%p, partid=%d, channel=%d\n", (void *) msg, partid, ch_number); DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS); DBUG_ON(ch_number < 0 || ch_number >= part->nchannels); DBUG_ON(msg == NULL); ret = xpc_send_msg(&part->channels[ch_number], msg, 0, NULL, NULL); return ret; } /* * Send a message previously allocated using xpc_initiate_allocate on the * specified channel connected to the specified partition. * * This routine will not wait for the message to be sent. Once this routine * has returned the message entry allocated via xpc_initiate_allocate() is no * longer accessable to the caller. * * Once the remote end of the channel has received the message, the function * passed as an argument to xpc_initiate_send_notify() will be called. This * allows the sender to free up or re-use any buffers referenced by the * message, but does NOT mean the message has been processed at the remote * end by a receiver. * * If this routine returns an error, the caller's function will NOT be called. * * This routine, although called by users, does not call xpc_part_ref() to * ensure that the partition infrastructure is in place. It relies on the * fact that we called xpc_msgqueue_ref() in xpc_allocate_msg(). * * Arguments: * * partid - ID of partition to which the channel is connected. * ch_number - channel # to send message on. * payload - pointer to the payload area allocated via * xpc_initiate_allocate(). * func - function to call with asynchronous notification of message * receipt. THIS FUNCTION MUST BE NON-BLOCKING. * key - user-defined key to be passed to the function when it's called. */ enum xpc_retval xpc_initiate_send_notify(partid_t partid, int ch_number, void *payload, xpc_notify_func func, void *key) { struct xpc_partition *part = &xpc_partitions[partid]; struct xpc_msg *msg = XPC_MSG_ADDRESS(payload); enum xpc_retval ret; dev_dbg(xpc_chan, "msg=0x%p, partid=%d, channel=%d\n", (void *) msg, partid, ch_number); DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS); DBUG_ON(ch_number < 0 || ch_number >= part->nchannels); DBUG_ON(msg == NULL); DBUG_ON(func == NULL); ret = xpc_send_msg(&part->channels[ch_number], msg, XPC_N_CALL, func, key); return ret; } static struct xpc_msg * xpc_pull_remote_msg(struct xpc_channel *ch, s64 get) { struct xpc_partition *part = &xpc_partitions[ch->partid]; struct xpc_msg *remote_msg, *msg; u32 msg_index, nmsgs; u64 msg_offset; enum xpc_retval ret; if (down_interruptible(&ch->msg_to_pull_sema) != 0) { /* we were interrupted by a signal */ return NULL; } while (get >= ch->next_msg_to_pull) { /* pull as many messages as are ready and able to be pulled */ msg_index = ch->next_msg_to_pull % ch->remote_nentries; DBUG_ON(ch->next_msg_to_pull >= (volatile s64) ch->w_remote_GP.put); nmsgs = (volatile s64) ch->w_remote_GP.put - ch->next_msg_to_pull; if (msg_index + nmsgs > ch->remote_nentries) { /* ignore the ones that wrap the msg queue for now */ nmsgs = ch->remote_nentries - msg_index; } msg_offset = msg_index * ch->msg_size; msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue + msg_offset); remote_msg = (struct xpc_msg *) (ch->remote_msgqueue_pa + msg_offset); if ((ret = xpc_pull_remote_cachelines(part, msg, remote_msg, nmsgs * ch->msg_size)) != xpcSuccess) { dev_dbg(xpc_chan, "failed to pull %d msgs starting with" " msg %ld from partition %d, channel=%d, " "ret=%d\n", nmsgs, ch->next_msg_to_pull, ch->partid, ch->number, ret); XPC_DEACTIVATE_PARTITION(part, ret); up(&ch->msg_to_pull_sema); return NULL; } mb(); /* >>> this may not be needed, we're not sure */ ch->next_msg_to_pull += nmsgs; } up(&ch->msg_to_pull_sema); /* return the message we were looking for */ msg_offset = (get % ch->remote_nentries) * ch->msg_size; msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue + msg_offset); return msg; } /* * Get a message to be delivered. */ static struct xpc_msg * xpc_get_deliverable_msg(struct xpc_channel *ch) { struct xpc_msg *msg = NULL; s64 get; do { if ((volatile u32) ch->flags & XPC_C_DISCONNECTING) { break; } get = (volatile s64) ch->w_local_GP.get; if (get == (volatile s64) ch->w_remote_GP.put) { break; } /* There are messages waiting to be pulled and delivered. * We need to try to secure one for ourselves. We'll do this * by trying to increment w_local_GP.get and hope that no one * else beats us to it. If they do, we'll we'll simply have * to try again for the next one. */ if (cmpxchg(&ch->w_local_GP.get, get, get + 1) == get) { /* we got the entry referenced by get */ dev_dbg(xpc_chan, "w_local_GP.get changed to %ld, " "partid=%d, channel=%d\n", get + 1, ch->partid, ch->number); /* pull the message from the remote partition */ msg = xpc_pull_remote_msg(ch, get); DBUG_ON(msg != NULL && msg->number != get); DBUG_ON(msg != NULL && (msg->flags & XPC_M_DONE)); DBUG_ON(msg != NULL && !(msg->flags & XPC_M_READY)); break; } } while (1); return msg; } /* * Deliver a message to its intended recipient. */ void xpc_deliver_msg(struct xpc_channel *ch) { struct xpc_msg *msg; if ((msg = xpc_get_deliverable_msg(ch)) != NULL) { /* * This ref is taken to protect the payload itself from being * freed before the user is finished with it, which the user * indicates by calling xpc_initiate_received(). */ xpc_msgqueue_ref(ch); atomic_inc(&ch->kthreads_active); if (ch->func != NULL) { dev_dbg(xpc_chan, "ch->func() called, msg=0x%p, " "msg_number=%ld, partid=%d, channel=%d\n", (void *) msg, msg->number, ch->partid, ch->number); /* deliver the message to its intended recipient */ ch->func(xpcMsgReceived, ch->partid, ch->number, &msg->payload, ch->key); dev_dbg(xpc_chan, "ch->func() returned, msg=0x%p, " "msg_number=%ld, partid=%d, channel=%d\n", (void *) msg, msg->number, ch->partid, ch->number); } atomic_dec(&ch->kthreads_active); } } /* * Now we actually acknowledge the messages that have been delivered and ack'd * by advancing the cached remote message queue's Get value and if requested * send an IPI to the message sender's partition. */ static void xpc_acknowledge_msgs(struct xpc_channel *ch, s64 initial_get, u8 msg_flags) { struct xpc_msg *msg; s64 get = initial_get + 1; int send_IPI = 0; while (1) { while (1) { if (get == (volatile s64) ch->w_local_GP.get) { break; } msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue + (get % ch->remote_nentries) * ch->msg_size); if (!(msg->flags & XPC_M_DONE)) { break; } msg_flags |= msg->flags; get++; } if (get == initial_get) { /* nothing's changed */ break; } if (cmpxchg_rel(&ch->local_GP->get, initial_get, get) != initial_get) { /* someone else beat us to it */ DBUG_ON((volatile s64) ch->local_GP->get <= initial_get); break; } /* we just set the new value of local_GP->get */ dev_dbg(xpc_chan, "local_GP->get changed to %ld, partid=%d, " "channel=%d\n", get, ch->partid, ch->number); send_IPI = (msg_flags & XPC_M_INTERRUPT); /* * We need to ensure that the message referenced by * local_GP->get is not XPC_M_DONE or that local_GP->get * equals w_local_GP.get, so we'll go have a look. */ initial_get = get; } if (send_IPI) { xpc_IPI_send_msgrequest(ch); } } /* * Acknowledge receipt of a delivered message. * * If a message has XPC_M_INTERRUPT set, send an interrupt to the partition * that sent the message. * * This function, although called by users, does not call xpc_part_ref() to * ensure that the partition infrastructure is in place. It relies on the * fact that we called xpc_msgqueue_ref() in xpc_deliver_msg(). * * Arguments: * * partid - ID of partition to which the channel is connected. * ch_number - channel # message received on. * payload - pointer to the payload area allocated via * xpc_initiate_allocate(). */ void xpc_initiate_received(partid_t partid, int ch_number, void *payload) { struct xpc_partition *part = &xpc_partitions[partid]; struct xpc_channel *ch; struct xpc_msg *msg = XPC_MSG_ADDRESS(payload); s64 get, msg_number = msg->number; DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS); DBUG_ON(ch_number < 0 || ch_number >= part->nchannels); ch = &part->channels[ch_number]; dev_dbg(xpc_chan, "msg=0x%p, msg_number=%ld, partid=%d, channel=%d\n", (void *) msg, msg_number, ch->partid, ch->number); DBUG_ON((((u64) msg - (u64) ch->remote_msgqueue) / ch->msg_size) != msg_number % ch->remote_nentries); DBUG_ON(msg->flags & XPC_M_DONE); msg->flags |= XPC_M_DONE; /* * The preceding store of msg->flags must occur before the following * load of ch->local_GP->get. */ mb(); /* * See if this message is next in line to be acknowledged as having * been delivered. */ get = ch->local_GP->get; if (get == msg_number) { xpc_acknowledge_msgs(ch, get, msg->flags); } /* the call to xpc_msgqueue_ref() was done by xpc_deliver_msg() */ xpc_msgqueue_deref(ch); }