v4.19.13 snapshot.
diff --git a/drivers/misc/sgi-xp/xp_main.c b/drivers/misc/sgi-xp/xp_main.c
new file mode 100644
index 0000000..6d7f557
--- /dev/null
+++ b/drivers/misc/sgi-xp/xp_main.c
@@ -0,0 +1,264 @@
+/*
+ * 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) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
+ */
+
+/*
+ * Cross Partition (XP) base.
+ *
+ *	XP provides a base from which its users can interact
+ *	with XPC, yet not be dependent on XPC.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include "xp.h"
+
+/* define the XP debug device structures to be used with dev_dbg() et al */
+
+struct device_driver xp_dbg_name = {
+	.name = "xp"
+};
+
+struct device xp_dbg_subname = {
+	.init_name = "",		/* set to "" */
+	.driver = &xp_dbg_name
+};
+
+struct device *xp = &xp_dbg_subname;
+
+/* max #of partitions possible */
+short xp_max_npartitions;
+EXPORT_SYMBOL_GPL(xp_max_npartitions);
+
+short xp_partition_id;
+EXPORT_SYMBOL_GPL(xp_partition_id);
+
+u8 xp_region_size;
+EXPORT_SYMBOL_GPL(xp_region_size);
+
+unsigned long (*xp_pa) (void *addr);
+EXPORT_SYMBOL_GPL(xp_pa);
+
+unsigned long (*xp_socket_pa) (unsigned long gpa);
+EXPORT_SYMBOL_GPL(xp_socket_pa);
+
+enum xp_retval (*xp_remote_memcpy) (unsigned long dst_gpa,
+				    const unsigned long src_gpa, size_t len);
+EXPORT_SYMBOL_GPL(xp_remote_memcpy);
+
+int (*xp_cpu_to_nasid) (int cpuid);
+EXPORT_SYMBOL_GPL(xp_cpu_to_nasid);
+
+enum xp_retval (*xp_expand_memprotect) (unsigned long phys_addr,
+					unsigned long size);
+EXPORT_SYMBOL_GPL(xp_expand_memprotect);
+enum xp_retval (*xp_restrict_memprotect) (unsigned long phys_addr,
+					  unsigned long size);
+EXPORT_SYMBOL_GPL(xp_restrict_memprotect);
+
+/*
+ * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
+ * users of XPC.
+ */
+struct xpc_registration xpc_registrations[XPC_MAX_NCHANNELS];
+EXPORT_SYMBOL_GPL(xpc_registrations);
+
+/*
+ * Initialize the XPC interface to NULL to indicate that XPC isn't loaded.
+ */
+struct xpc_interface xpc_interface = { };
+EXPORT_SYMBOL_GPL(xpc_interface);
+
+/*
+ * XPC calls this when it (the XPC module) has been loaded.
+ */
+void
+xpc_set_interface(void (*connect) (int),
+		  void (*disconnect) (int),
+		  enum xp_retval (*send) (short, int, u32, void *, u16),
+		  enum xp_retval (*send_notify) (short, int, u32, void *, u16,
+						  xpc_notify_func, void *),
+		  void (*received) (short, int, void *),
+		  enum xp_retval (*partid_to_nasids) (short, void *))
+{
+	xpc_interface.connect = connect;
+	xpc_interface.disconnect = disconnect;
+	xpc_interface.send = send;
+	xpc_interface.send_notify = send_notify;
+	xpc_interface.received = received;
+	xpc_interface.partid_to_nasids = partid_to_nasids;
+}
+EXPORT_SYMBOL_GPL(xpc_set_interface);
+
+/*
+ * XPC calls this when it (the XPC module) is being unloaded.
+ */
+void
+xpc_clear_interface(void)
+{
+	memset(&xpc_interface, 0, sizeof(xpc_interface));
+}
+EXPORT_SYMBOL_GPL(xpc_clear_interface);
+
+/*
+ * Register for automatic establishment of a channel connection whenever
+ * a partition comes up.
+ *
+ * Arguments:
+ *
+ *	ch_number - channel # to register for connection.
+ *	func - function to call for asynchronous notification of channel
+ *	       state changes (i.e., connection, disconnection, error) and
+ *	       the arrival of incoming messages.
+ *      key - pointer to optional user-defined value that gets passed back
+ *	      to the user on any callouts made to func.
+ *	payload_size - size in bytes of the XPC message's payload area which
+ *		       contains a user-defined message. The user should make
+ *		       this large enough to hold their largest message.
+ *	nentries - max #of XPC message entries a message queue can contain.
+ *		   The actual number, which is determined when a connection
+ * 		   is established and may be less then requested, will be
+ *		   passed to the user via the xpConnected callout.
+ *	assigned_limit - max number of kthreads allowed to be processing
+ * 			 messages (per connection) at any given instant.
+ *	idle_limit - max number of kthreads allowed to be idle at any given
+ * 		     instant.
+ */
+enum xp_retval
+xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
+	    u16 nentries, u32 assigned_limit, u32 idle_limit)
+{
+	struct xpc_registration *registration;
+
+	DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
+	DBUG_ON(payload_size == 0 || nentries == 0);
+	DBUG_ON(func == NULL);
+	DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
+
+	if (XPC_MSG_SIZE(payload_size) > XPC_MSG_MAX_SIZE)
+		return xpPayloadTooBig;
+
+	registration = &xpc_registrations[ch_number];
+
+	if (mutex_lock_interruptible(&registration->mutex) != 0)
+		return xpInterrupted;
+
+	/* if XPC_CHANNEL_REGISTERED(ch_number) */
+	if (registration->func != NULL) {
+		mutex_unlock(&registration->mutex);
+		return xpAlreadyRegistered;
+	}
+
+	/* register the channel for connection */
+	registration->entry_size = XPC_MSG_SIZE(payload_size);
+	registration->nentries = nentries;
+	registration->assigned_limit = assigned_limit;
+	registration->idle_limit = idle_limit;
+	registration->key = key;
+	registration->func = func;
+
+	mutex_unlock(&registration->mutex);
+
+	if (xpc_interface.connect)
+		xpc_interface.connect(ch_number);
+
+	return xpSuccess;
+}
+EXPORT_SYMBOL_GPL(xpc_connect);
+
+/*
+ * Remove the registration for automatic connection of the specified channel
+ * when a partition comes up.
+ *
+ * Before returning this xpc_disconnect() will wait for 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 their
+ * function registered via xpc_connect().
+ *
+ * Arguments:
+ *
+ *	ch_number - channel # to unregister.
+ */
+void
+xpc_disconnect(int ch_number)
+{
+	struct xpc_registration *registration;
+
+	DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
+
+	registration = &xpc_registrations[ch_number];
+
+	/*
+	 * We've decided not to make this a down_interruptible(), since we
+	 * figured XPC's users will just turn around and call xpc_disconnect()
+	 * again anyways, so we might as well wait, if need be.
+	 */
+	mutex_lock(&registration->mutex);
+
+	/* if !XPC_CHANNEL_REGISTERED(ch_number) */
+	if (registration->func == NULL) {
+		mutex_unlock(&registration->mutex);
+		return;
+	}
+
+	/* remove the connection registration for the specified channel */
+	registration->func = NULL;
+	registration->key = NULL;
+	registration->nentries = 0;
+	registration->entry_size = 0;
+	registration->assigned_limit = 0;
+	registration->idle_limit = 0;
+
+	if (xpc_interface.disconnect)
+		xpc_interface.disconnect(ch_number);
+
+	mutex_unlock(&registration->mutex);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(xpc_disconnect);
+
+int __init
+xp_init(void)
+{
+	enum xp_retval ret;
+	int ch_number;
+
+	/* initialize the connection registration mutex */
+	for (ch_number = 0; ch_number < XPC_MAX_NCHANNELS; ch_number++)
+		mutex_init(&xpc_registrations[ch_number].mutex);
+
+	if (is_shub())
+		ret = xp_init_sn2();
+	else if (is_uv())
+		ret = xp_init_uv();
+	else
+		ret = 0;
+
+	if (ret != xpSuccess)
+		return ret;
+
+	return 0;
+}
+
+module_init(xp_init);
+
+void __exit
+xp_exit(void)
+{
+	if (is_shub())
+		xp_exit_sn2();
+	else if (is_uv())
+		xp_exit_uv();
+}
+
+module_exit(xp_exit);
+
+MODULE_AUTHOR("Silicon Graphics, Inc.");
+MODULE_DESCRIPTION("Cross Partition (XP) base");
+MODULE_LICENSE("GPL");