sgi-xp: isolate xpc_vars_part structure to sn2 only

Isolate the xpc_vars_part structure of XPC's reserved page to sn2 only.

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 560 insertions, 3 deletions

diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index 5a373487..ee28e23 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/drivers/misc/sgi-xp/xpc_sn2.c
@@ -14,12 +14,13 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/delay.h>
 #include <asm/uncached.h>
 #include <asm/sn/sn_sal.h>
 #include "xpc.h"
 
 struct xpc_vars *xpc_vars;
-struct xpc_vars_part *xpc_vars_part;
+static struct xpc_vars_part_sn2 *xpc_vars_part; /* >>> Add _sn2 suffix? */
 
 static enum xp_retval
 xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
@@ -33,7 +34,10 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
 
 	rp->sn.vars_pa = __pa(xpc_vars);
 
-	xpc_vars_part = XPC_RP_VARS_PART(rp);
+	/* vars_part array follows immediately after vars */
+	xpc_vars_part = (struct xpc_vars_part_sn2 *)((u8 *)XPC_RP_VARS(rp) +
+						     XPC_RP_VARS_SIZE);
+
 
 	/*
 	 * Before clearing xpc_vars, see if a page of AMOs had been previously
@@ -85,7 +89,7 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
 	xpc_vars->amos_page = amos_page;	/* save for next load of XPC */
 
 	/* clear xpc_vars_part */
-	memset((u64 *)xpc_vars_part, 0, sizeof(struct xpc_vars_part) *
+	memset((u64 *)xpc_vars_part, 0, sizeof(struct xpc_vars_part_sn2) *
 	       xp_max_npartitions);
 
 	/* initialize the activate IRQ related AMO variables */
@@ -99,10 +103,563 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
 	return xpSuccess;
 }
 
+/*
+ * Setup the infrastructure necessary to support XPartition Communication
+ * between the specified remote partition and the local one.
+ */
+static enum xp_retval
+xpc_setup_infrastructure_sn2(struct xpc_partition *part)
+{
+	enum xp_retval retval;
+	int ret;
+	int cpuid;
+	int ch_number;
+	struct xpc_channel *ch;
+	struct timer_list *timer;
+	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 all the required GET/PUT values */
+
+	part->local_GPs = xpc_kzalloc_cacheline_aligned(XPC_GP_SIZE,
+							GFP_KERNEL,
+							&part->local_GPs_base);
+	if (part->local_GPs == NULL) {
+		dev_err(xpc_chan, "can't get memory for local get/put "
+			"values\n");
+		retval = xpNoMemory;
+		goto out_1;
+	}
+
+	part->remote_GPs = xpc_kzalloc_cacheline_aligned(XPC_GP_SIZE,
+							 GFP_KERNEL,
+							 &part->
+							 remote_GPs_base);
+	if (part->remote_GPs == NULL) {
+		dev_err(xpc_chan, "can't get memory for remote get/put "
+			"values\n");
+		retval = xpNoMemory;
+		goto out_2;
+	}
+
+	part->remote_GPs_pa = 0;
+
+	/* allocate all the required open and close args */
+
+	part->local_openclose_args =
+	    xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
+					  &part->local_openclose_args_base);
+	if (part->local_openclose_args == NULL) {
+		dev_err(xpc_chan, "can't get memory for local connect args\n");
+		retval = xpNoMemory;
+		goto out_3;
+	}
+
+	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");
+		retval = xpNoMemory;
+		goto out_4;
+	}
+
+	part->remote_openclose_args_pa = 0;
+
+	part->local_IPI_amo_va = xpc_IPI_init(partid);
+	part->local_IPI_amo = 0;
+	spin_lock_init(&part->IPI_lock);
+
+	part->remote_IPI_nasid = 0;
+	part->remote_IPI_phys_cpuid = 0;
+	part->remote_IPI_amo_va = NULL;
+
+	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, IRQF_SHARED,
+			  part->IPI_owner, (void *)(u64)partid);
+	if (ret != 0) {
+		dev_err(xpc_chan, "can't register NOTIFY IRQ handler, "
+			"errno=%d\n", -ret);
+		retval = xpLackOfResources;
+		goto out_5;
+	}
+
+	/* 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_INTERVAL;
+	add_timer(timer);
+
+	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;
+
+		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);
+		mutex_init(&ch->msg_to_pull_mutex);
+		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);
+	}
+
+	/*
+	 * 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 xpSuccess;
+
+	/* setup of infrastructure failed */
+out_5:
+	kfree(part->remote_openclose_args_base);
+	part->remote_openclose_args = NULL;
+out_4:
+	kfree(part->local_openclose_args_base);
+	part->local_openclose_args = NULL;
+out_3:
+	kfree(part->remote_GPs_base);
+	part->remote_GPs = NULL;
+out_2:
+	kfree(part->local_GPs_base);
+	part->local_GPs = NULL;
+out_1:
+	kfree(part->channels);
+	part->channels = NULL;
+	return retval;
+}
+
+/*
+ * Teardown the infrastructure necessary to support XPartition Communication
+ * between the specified remote partition and the local one.
+ */
+static void
+xpc_teardown_infrastructure_sn2(struct xpc_partition *part)
+{
+	short 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 proceeding 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;
+}
+
+/*
+ * 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 cacheline sized
+ */
+/* >>> Replace this function by call to xp_remote_memcpy() or bte_copy()? */
+static enum xp_retval
+xpc_pull_remote_cachelines_sn2(struct xpc_partition *part, void *dst,
+			       const void *src, size_t cnt)
+{
+	enum xp_retval 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;
+
+	ret = xp_remote_memcpy(dst, src, cnt);
+	if (ret != xpSuccess) {
+		dev_dbg(xpc_chan, "xp_remote_memcpy() from partition %d failed,"
+			" ret=%d\n", XPC_PARTID(part), ret);
+	}
+	return ret;
+}
+
+/*
+ * Pull the remote per partition specific variables from the specified
+ * partition.
+ */
+static enum xp_retval
+xpc_pull_remote_vars_part_sn2(struct xpc_partition *part)
+{
+	u8 buffer[L1_CACHE_BYTES * 2];
+	struct xpc_vars_part_sn2 *pulled_entry_cacheline =
+	    (struct xpc_vars_part_sn2 *)L1_CACHE_ALIGN((u64)buffer);
+	struct xpc_vars_part_sn2 *pulled_entry;
+	u64 remote_entry_cacheline_pa, remote_entry_pa;
+	short partid = XPC_PARTID(part);
+	enum xp_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_sn2) != L1_CACHE_BYTES / 2);
+
+	remote_entry_pa = part->remote_vars_part_pa +
+	    sn_partition_id * sizeof(struct xpc_vars_part_sn2);
+
+	remote_entry_cacheline_pa = (remote_entry_pa & ~(L1_CACHE_BYTES - 1));
+
+	pulled_entry = (struct xpc_vars_part_sn2 *)((u64)pulled_entry_cacheline
+						    + (remote_entry_pa &
+						    (L1_CACHE_BYTES - 1)));
+
+	ret = xpc_pull_remote_cachelines_sn2(part, pulled_entry_cacheline,
+					     (void *)remote_entry_cacheline_pa,
+					     L1_CACHE_BYTES);
+	if (ret != xpSuccess) {
+		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 xpBadMagic;
+		}
+
+		/* they've not been initialized yet */
+		return xpRetry;
+	}
+
+	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 xpInvalidAddress;
+		}
+
+		/* 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 xpRetry;
+
+	return xpSuccess;
+}
+
+/*
+ * Establish first contact with the remote partititon. This involves pulling
+ * the XPC per partition variables from the remote partition and waiting for
+ * the remote partition to pull ours.
+ */
+static enum xp_retval
+xpc_make_first_contact_sn2(struct xpc_partition *part)
+{
+	enum xp_retval ret;
+
+	while ((ret = xpc_pull_remote_vars_part_sn2(part)) != xpSuccess) {
+		if (ret != xpRetry) {
+			XPC_DEACTIVATE_PARTITION(part, ret);
+			return ret;
+		}
+
+		dev_dbg(xpc_part, "waiting to make first contact with "
+			"partition %d\n", XPC_PARTID(part));
+
+		/* wait a 1/4 of a second or so */
+		(void)msleep_interruptible(250);
+
+		if (part->act_state == XPC_P_DEACTIVATING)
+			return part->reason;
+	}
+
+	return xpSuccess;
+}
+
+/*
+ * Get the IPI flags and pull the openclose args and/or remote GPs as needed.
+ */
+static u64
+xpc_get_IPI_flags_sn2(struct xpc_partition *part)
+{
+	unsigned long irq_flags;
+	u64 IPI_amo;
+	enum xp_retval ret;
+
+	/*
+	 * See if there are any IPI flags to be handled.
+	 */
+
+	spin_lock_irqsave(&part->IPI_lock, irq_flags);
+	IPI_amo = part->local_IPI_amo;
+	if (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_sn2(part,
+						    part->remote_openclose_args,
+						     (void *)part->
+						     remote_openclose_args_pa,
+						     XPC_OPENCLOSE_ARGS_SIZE);
+		if (ret != xpSuccess) {
+			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_sn2(part, part->remote_GPs,
+						    (void *)part->remote_GPs_pa,
+						     XPC_GP_SIZE);
+		if (ret != xpSuccess) {
+			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;
+}
+
+static struct xpc_msg *
+xpc_pull_remote_msg_sn2(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 xp_retval ret;
+
+	if (mutex_lock_interruptible(&ch->msg_to_pull_mutex) != 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 >= ch->w_remote_GP.put);
+		nmsgs = 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);
+
+		ret = xpc_pull_remote_cachelines_sn2(part, msg, remote_msg,
+						     nmsgs * ch->msg_size);
+		if (ret != xpSuccess) {
+
+			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);
+
+			mutex_unlock(&ch->msg_to_pull_mutex);
+			return NULL;
+		}
+
+		ch->next_msg_to_pull += nmsgs;
+	}
+
+	mutex_unlock(&ch->msg_to_pull_mutex);
+
+	/* 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_sn2(struct xpc_channel *ch)
+{
+	struct xpc_msg *msg = NULL;
+	s64 get;
+
+	do {
+		if (ch->flags & XPC_C_DISCONNECTING)
+			break;
+
+		get = ch->w_local_GP.get;
+		rmb();	/* guarantee that .get loads before .put */
+		if (get == 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_sn2(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;
+}
+
 void
 xpc_init_sn2(void)
 {
 	xpc_rsvd_page_init = xpc_rsvd_page_init_sn2;
+	xpc_setup_infrastructure = xpc_setup_infrastructure_sn2;
+	xpc_teardown_infrastructure = xpc_teardown_infrastructure_sn2;
+	xpc_make_first_contact = xpc_make_first_contact_sn2;
+	xpc_get_IPI_flags = xpc_get_IPI_flags_sn2;
+	xpc_get_deliverable_msg = xpc_get_deliverable_msg_sn2;
 }
 
 void