[IA64-SGI] SGI Altix cross partition functionality (2nd

This patch contains the shim module (XP) which interfaces between the
communication module (XPC) and the functional support modules (like XPNET).

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/Kconfig

@@ -217,6 +217,16 @@ config IA64_SGI_SN_SIM
 	  If you are compiling a kernel that will run under SGI's IA-64
 	  simulator (Medusa) then say Y, otherwise say N.
 
+config IA64_SGI_SN_XP
+	tristate "Support communication between SGI SSIs"
+	depends on MSPEC
+	help
+	  An SGI machine can be divided into multiple Single System
+	  Images which act independently of each other and have
+	  hardware based memory protection from the others.  Enabling
+	  this feature will allow for direct communication between SSIs
+	  based on a network adapter and DMA messaging.
+
 config FORCE_MAX_ZONEORDER
 	int
 	default "18"

arch/ia64/sn/kernel/xp_main.c

@@ -0,0 +1,289 @@
+/*
+ * 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 (XP) base.
+ *
+ *	XP provides a base from which its users can interact
+ *	with XPC, yet not be dependent on XPC.
+ *
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <asm/sn/intr.h>
+#include <asm/sn/sn_sal.h>
+#include <asm/sn/xp.h>
+
+
+/*
+ * Target of nofault PIO read.
+ */
+u64 xp_nofault_PIOR_target;
+
+
+/*
+ * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
+ * users of XPC.
+ */
+struct xpc_registration xpc_registrations[XPC_NCHANNELS];
+
+
+/*
+ * Initialize the XPC interface to indicate that XPC isn't loaded.
+ */
+static enum xpc_retval xpc_notloaded(void) { return xpcNotLoaded; }
+
+struct xpc_interface xpc_interface = {
+	(void (*)(int)) xpc_notloaded,
+	(void (*)(int)) xpc_notloaded,
+	(enum xpc_retval (*)(partid_t, int, u32, void **)) xpc_notloaded,
+	(enum xpc_retval (*)(partid_t, int, void *)) xpc_notloaded,
+	(enum xpc_retval (*)(partid_t, int, void *, xpc_notify_func, void *))
+							xpc_notloaded,
+	(void (*)(partid_t, int, void *)) xpc_notloaded,
+	(enum xpc_retval (*)(partid_t, void *)) xpc_notloaded
+};
+
+
+/*
+ * XPC calls this when it (the XPC module) has been loaded.
+ */
+void
+xpc_set_interface(void (*connect)(int),
+		void (*disconnect)(int),
+		enum xpc_retval (*allocate)(partid_t, int, u32, void **),
+		enum xpc_retval (*send)(partid_t, int, void *),
+		enum xpc_retval (*send_notify)(partid_t, int, void *,
+						xpc_notify_func, void *),
+		void (*received)(partid_t, int, void *),
+		enum xpc_retval (*partid_to_nasids)(partid_t, void *))
+{
+	xpc_interface.connect = connect;
+	xpc_interface.disconnect = disconnect;
+	xpc_interface.allocate = allocate;
+	xpc_interface.send = send;
+	xpc_interface.send_notify = send_notify;
+	xpc_interface.received = received;
+	xpc_interface.partid_to_nasids = partid_to_nasids;
+}
+
+
+/*
+ * XPC calls this when it (the XPC module) is being unloaded.
+ */
+void
+xpc_clear_interface(void)
+{
+	xpc_interface.connect = (void (*)(int)) xpc_notloaded;
+	xpc_interface.disconnect = (void (*)(int)) xpc_notloaded;
+	xpc_interface.allocate = (enum xpc_retval (*)(partid_t, int, u32,
+					void **)) xpc_notloaded;
+	xpc_interface.send = (enum xpc_retval (*)(partid_t, int, void *))
+					xpc_notloaded;
+	xpc_interface.send_notify = (enum xpc_retval (*)(partid_t, int, void *,
+				    xpc_notify_func, void *)) xpc_notloaded;
+	xpc_interface.received = (void (*)(partid_t, int, void *))
+					xpc_notloaded;
+	xpc_interface.partid_to_nasids = (enum xpc_retval (*)(partid_t, void *))
+					xpc_notloaded;
+}
+
+
+/*
+ * 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 xpcConnected 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 xpc_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_NCHANNELS);
+	DBUG_ON(payload_size == 0 || nentries == 0);
+	DBUG_ON(func == NULL);
+	DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
+
+	registration = &xpc_registrations[ch_number];
+
+	if (down_interruptible(&registration->sema) != 0) {
+		return xpcInterrupted;
+	}
+
+	/* if XPC_CHANNEL_REGISTERED(ch_number) */
+	if (registration->func != NULL) {
+		up(&registration->sema);
+		return xpcAlreadyRegistered;
+	}
+
+	/* register the channel for connection */
+	registration->msg_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;
+
+	up(&registration->sema);
+
+	xpc_interface.connect(ch_number);
+
+	return xpcSuccess;
+}
+
+
+/*
+ * 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_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.
+	 */
+	down(&registration->sema);
+
+	/* if !XPC_CHANNEL_REGISTERED(ch_number) */
+	if (registration->func == NULL) {
+		up(&registration->sema);
+		return;
+	}
+
+	/* remove the connection registration for the specified channel */
+	registration->func = NULL;
+	registration->key = NULL;
+	registration->nentries = 0;
+	registration->msg_size = 0;
+	registration->assigned_limit = 0;
+	registration->idle_limit = 0;
+
+	xpc_interface.disconnect(ch_number);
+
+	up(&registration->sema);
+
+	return;
+}
+
+
+int __init
+xp_init(void)
+{
+	int ret, ch_number;
+	u64 func_addr = *(u64 *) xp_nofault_PIOR;
+	u64 err_func_addr = *(u64 *) xp_error_PIOR;
+
+
+	if (!ia64_platform_is("sn2")) {
+		return -ENODEV;
+	}
+
+	/*
+	 * Register a nofault code region which performs a cross-partition
+	 * PIO read. If the PIO read times out, the MCA handler will consume
+	 * the error and return to a kernel-provided instruction to indicate
+	 * an error. This PIO read exists because it is guaranteed to timeout
+	 * if the destination is down (AMO operations do not timeout on at
+	 * least some CPUs on Shubs <= v1.2, which unfortunately we have to
+	 * work around).
+	 */
+	if ((ret = sn_register_nofault_code(func_addr, err_func_addr,
+						err_func_addr, 1, 1)) != 0) {
+		printk(KERN_ERR "XP: can't register nofault code, error=%d\n",
+			ret);
+	}
+	/*
+	 * Setup the nofault PIO read target. (There is no special reason why
+	 * SH_IPI_ACCESS was selected.)
+	 */
+	if (is_shub2()) {
+		xp_nofault_PIOR_target = SH2_IPI_ACCESS0;
+	} else {
+		xp_nofault_PIOR_target = SH1_IPI_ACCESS;
+	}
+
+	/* initialize the connection registration semaphores */
+	for (ch_number = 0; ch_number < XPC_NCHANNELS; ch_number++) {
+		sema_init(&xpc_registrations[ch_number].sema, 1);  /* mutex */
+	}
+
+	return 0;
+}
+module_init(xp_init);
+
+
+void __exit
+xp_exit(void)
+{
+	u64 func_addr = *(u64 *) xp_nofault_PIOR;
+	u64 err_func_addr = *(u64 *) xp_error_PIOR;
+
+
+	/* unregister the PIO read nofault code region */
+	(void) sn_register_nofault_code(func_addr, err_func_addr,
+					err_func_addr, 1, 0);
+}
+module_exit(xp_exit);
+
+
+MODULE_AUTHOR("Silicon Graphics, Inc.");
+MODULE_DESCRIPTION("Cross Partition (XP) base");
+MODULE_LICENSE("GPL");
+
+EXPORT_SYMBOL(xp_nofault_PIOR);
+EXPORT_SYMBOL(xp_nofault_PIOR_target);
+EXPORT_SYMBOL(xpc_registrations);
+EXPORT_SYMBOL(xpc_interface);
+EXPORT_SYMBOL(xpc_clear_interface);
+EXPORT_SYMBOL(xpc_set_interface);
+EXPORT_SYMBOL(xpc_connect);
+EXPORT_SYMBOL(xpc_disconnect);
+

arch/ia64/sn/kernel/xp_nofault.S

@@ -0,0 +1,31 @@
+/*
+ * 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.
+ */
+
+
+/*
+ * The xp_nofault_PIOR function takes a pointer to a remote PIO register
+ * and attempts to load and consume a value from it.  This function
+ * will be registered as a nofault code block.  In the event that the
+ * PIO read fails, the MCA handler will force the error to look
+ * corrected and vector to the xp_error_PIOR which will return an error.
+ *
+ *	extern int xp_nofault_PIOR(void *remote_register);
+ */
+
+	.global xp_nofault_PIOR
+xp_nofault_PIOR:
+	mov	r8=r0			// Stage a success return value
+	ld8.acq	r9=[r32];;		// PIO Read the specified register
+	adds	r9=1,r9			// Add to force a consume
+	br.ret.sptk.many b0;;		// Return success
+
+	.global xp_error_PIOR
+xp_error_PIOR:
+	mov	r8=1			// Return value of 1
+	br.ret.sptk.many b0;;		// Return failure
+