[Patch 08/18] isolate xpc_vars structure to sn2 only

[Dean Nelson]

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

Signed-off-by: Dean Nelson <dcn@xxxxxxx>

---

 drivers/misc/sgi-xp/xpc.h           |  529 ++------------
 drivers/misc/sgi-xp/xpc_channel.c   |  315 --------
 drivers/misc/sgi-xp/xpc_main.c      |  152 ++--
 drivers/misc/sgi-xp/xpc_partition.c |  454 ------------
 drivers/misc/sgi-xp/xpc_sn2.c       | 1181 +++++++++++++++++++++++++++++++-
 drivers/misc/sgi-xp/xpc_uv.c        |   57 +
 6 files changed, 1433 insertions(+), 1255 deletions(-)

Index: linux-2.6/drivers/misc/sgi-xp/xpc.h
===================================================================
--- linux-2.6.orig/drivers/misc/sgi-xp/xpc.h	2008-05-28 07:03:09.360488680 -0500
+++ linux-2.6/drivers/misc/sgi-xp/xpc.h	2008-05-28 07:03:15.269223054 -0500
@@ -159,10 +159,10 @@ xpc_compare_stamps(struct timespec *stam
  * reflected by incrementing either the major or minor version numbers
  * of struct xpc_vars.
  */
-struct xpc_vars {
+struct xpc_vars_sn2 {
 	u8 version;
 	u64 heartbeat;
-	u64 heartbeating_to_mask;
+	DECLARE_BITMAP(heartbeating_to_mask, XP_MAX_NPARTITIONS_SN2);
 	u64 heartbeat_offline;	/* if 0, heartbeat should be changing */
 	int act_nasid;
 	int act_phys_cpuid;
@@ -176,46 +176,23 @@ struct xpc_vars {
 #define XPC_SUPPORTS_DISENGAGE_REQUEST(_version) \
 			(_version >= _XPC_VERSION(3, 1))
 
-static inline int
-xpc_hb_allowed(short partid, struct xpc_vars *vars)
-{
-	return ((vars->heartbeating_to_mask & (1UL << partid)) != 0);
-}
-
-static inline void
-xpc_allow_hb(short partid, struct xpc_vars *vars)
-{
-	u64 old_mask, new_mask;
-
-	do {
-		old_mask = vars->heartbeating_to_mask;
-		new_mask = (old_mask | (1UL << partid));
-	} while (cmpxchg(&vars->heartbeating_to_mask, old_mask, new_mask) !=
-		 old_mask);
-}
-
-static inline void
-xpc_disallow_hb(short partid, struct xpc_vars *vars)
-{
-	u64 old_mask, new_mask;
-
-	do {
-		old_mask = vars->heartbeating_to_mask;
-		new_mask = (old_mask & ~(1UL << partid));
-	} while (cmpxchg(&vars->heartbeating_to_mask, old_mask, new_mask) !=
-		 old_mask);
-}
-
 /*
- * The AMOs page consists of a number of AMO variables which are divided into
- * four groups, The first two groups are used to identify an IRQ's sender.
- * These two groups consist of 64 and 128 AMO variables respectively. The last
- * two groups, consisting of just one AMO variable each, are used to identify
- * the remote partitions that are currently engaged (from the viewpoint of
- * the XPC running on the remote partition).
+ * The following pertains to ia64-sn2 only.
+ *
+ * Memory for XPC's AMO variables is allocated by the MSPEC driver. These
+ * pages are located in the lowest granule. The lowest granule uses 4k pages
+ * for cached references and an alternate TLB handler to never provide a
+ * cacheable mapping for the entire region. This will prevent speculative
+ * reading of cached copies of our lines from being issued which will cause
+ * a PI FSB Protocol error to be generated by the SHUB. For XPC, we need 64
+ * AMO variables (based on XP_MAX_NPARTITIONS_SN2) to identify the senders of
+ * NOTIFY IRQs, 128 AMO variables (based on XP_NASID_MASK_WORDS) to identify
+ * the senders of ACTIVATE IRQs, and 2 AMO variables to identify which remote
+ * partitions (i.e., XPCs) consider themselves currently engaged with the
+ * local XPC.
  */
-#define XPC_NOTIFY_IRQ_AMOS	   0
-#define XPC_ACTIVATE_IRQ_AMOS	   (XPC_NOTIFY_IRQ_AMOS + XP_MAX_NPARTITIONS_SN2)
+#define XPC_NOTIFY_IRQ_AMOS	0
+#define XPC_ACTIVATE_IRQ_AMOS	(XPC_NOTIFY_IRQ_AMOS + XP_MAX_NPARTITIONS_SN2)
 #define XPC_ENGAGED_PARTITIONS_AMO (XPC_ACTIVATE_IRQ_AMOS + XP_NASID_MASK_WORDS)
 #define XPC_DISENGAGE_REQUEST_AMO  (XPC_ENGAGED_PARTITIONS_AMO + 1)
 
@@ -259,11 +236,11 @@ struct xpc_vars_part_sn2 {
 /* the reserved page sizes and offsets */
 
 #define XPC_RP_HEADER_SIZE	L1_CACHE_ALIGN(sizeof(struct xpc_rsvd_page))
-#define XPC_RP_VARS_SIZE	L1_CACHE_ALIGN(sizeof(struct xpc_vars))
+#define XPC_RP_VARS_SIZE	L1_CACHE_ALIGN(sizeof(struct xpc_vars_sn2))
 
 #define XPC_RP_PART_NASIDS(_rp) ((u64 *)((u8 *)(_rp) + XPC_RP_HEADER_SIZE))
 #define XPC_RP_MACH_NASIDS(_rp) (XPC_RP_PART_NASIDS(_rp) + xp_nasid_mask_words)
-#define XPC_RP_VARS(_rp)	((struct xpc_vars *)(XPC_RP_MACH_NASIDS(_rp) + \
+#define XPC_RP_VARS(_rp)	((struct xpc_vars_sn2 *)(XPC_RP_MACH_NASIDS(_rp) + \
 				    xp_nasid_mask_words))
 
 /*
@@ -344,6 +321,7 @@ struct xpc_notify {
  * allocated at the time a partition becomes active. The array contains one
  * of these structures for each potential channel connection to that partition.
  *
+>>> sn2 only!!!
  * Each of these structures manages two message queues (circular buffers).
  * They are allocated at the time a channel connection is made. One of
  * these message queues (local_msgqueue) holds the locally created messages
@@ -622,6 +600,9 @@ extern struct device *xpc_part;
 extern struct device *xpc_chan;
 extern int xpc_disengage_request_timelimit;
 extern int xpc_disengage_request_timedout;
+extern atomic_t xpc_act_IRQ_rcvd;
+extern wait_queue_head_t xpc_act_IRQ_wq;
+extern void *xpc_heartbeating_to_mask;
 extern irqreturn_t xpc_notify_IRQ_handler(int, void *);
 extern void xpc_dropped_IPI_check(struct xpc_partition *);
 extern void xpc_activate_partition(struct xpc_partition *);
@@ -629,15 +610,48 @@ extern void xpc_activate_kthreads(struct
 extern void xpc_create_kthreads(struct xpc_channel *, int, int);
 extern void xpc_disconnect_wait(int);
 extern enum xp_retval (*xpc_rsvd_page_init) (struct xpc_rsvd_page *);
+extern void (*xpc_heartbeat_init) (void);
+extern void (*xpc_heartbeat_exit) (void);
+extern void (*xpc_increment_heartbeat) (void);
+extern void (*xpc_offline_heartbeat) (void);
+extern void (*xpc_online_heartbeat) (void);
+extern void (*xpc_check_remote_hb) (void);
 extern enum xp_retval (*xpc_make_first_contact) (struct xpc_partition *);
 extern u64 (*xpc_get_IPI_flags) (struct xpc_partition *);
 extern struct xpc_msg *(*xpc_get_deliverable_msg) (struct xpc_channel *);
+extern void (*xpc_initiate_partition_activation) (struct xpc_rsvd_page *, u64,
+						  int);
+extern void (*xpc_process_act_IRQ_rcvd) (int);
 extern enum xp_retval (*xpc_setup_infrastructure) (struct xpc_partition *);
 extern void (*xpc_teardown_infrastructure) (struct xpc_partition *);
+extern void (*xpc_mark_partition_engaged) (struct xpc_partition *);
+extern void (*xpc_mark_partition_disengaged) (struct xpc_partition *);
+extern void (*xpc_request_partition_disengage) (struct xpc_partition *);
+extern void (*xpc_cancel_partition_disengage_request) (struct xpc_partition *);
+extern u64 (*xpc_partition_engaged) (u64);
+extern u64 (*xpc_partition_disengage_requested) (u64);;
+extern void (*xpc_clear_partition_engaged) (u64);
+extern void (*xpc_clear_partition_disengage_request) (u64);
+
+extern void (*xpc_IPI_send_local_activate) (int);
+extern void (*xpc_IPI_send_activated) (struct xpc_partition *);
+extern void (*xpc_IPI_send_local_reactivate) (int);
+extern void (*xpc_IPI_send_disengage) (struct xpc_partition *);
+
+extern void (*xpc_IPI_send_closerequest) (struct xpc_channel *,
+					  unsigned long *);
+extern void (*xpc_IPI_send_closereply) (struct xpc_channel *, unsigned long *);
+extern void (*xpc_IPI_send_openrequest) (struct xpc_channel *, unsigned long *);
+extern void (*xpc_IPI_send_openreply) (struct xpc_channel *, unsigned long *);
+
+extern enum xp_retval (*xpc_allocate_msg) (struct xpc_channel *, u32,
+					   struct xpc_msg **);
+extern enum xp_retval (*xpc_send_msg) (struct xpc_channel *, struct xpc_msg *,
+				       u8, xpc_notify_func, void *);
+extern void (*xpc_received_msg) (struct xpc_channel *, struct xpc_msg *);
 
 /* found in xpc_sn2.c */
 extern void xpc_init_sn2(void);
-extern struct xpc_vars *xpc_vars;		/*>>> eliminate from here */
 
 /* found in xpc_uv.c */
 extern void xpc_init_uv(void);
@@ -646,6 +660,7 @@ extern void xpc_init_uv(void);
 extern int xpc_exiting;
 extern int xp_nasid_mask_words;
 extern struct xpc_rsvd_page *xpc_rsvd_page;
+extern u64 *xpc_mach_nasids;
 extern struct xpc_partition *xpc_partitions;
 extern char *xpc_remote_copy_buffer;
 extern void *xpc_remote_copy_buffer_base;
@@ -658,7 +673,8 @@ extern int xpc_partition_disengaged(stru
 extern enum xp_retval xpc_mark_partition_active(struct xpc_partition *);
 extern void xpc_mark_partition_inactive(struct xpc_partition *);
 extern void xpc_discovery(void);
-extern void xpc_check_remote_hb(void);
+extern enum xp_retval xpc_get_remote_rp(int, u64 *, struct xpc_rsvd_page *,
+					u64 *);
 extern void xpc_deactivate_partition(const int, struct xpc_partition *,
 				     enum xp_retval);
 extern enum xp_retval xpc_initiate_partid_to_nasids(short, void *);
@@ -667,6 +683,7 @@ extern enum xp_retval xpc_initiate_parti
 extern void *xpc_kzalloc_cacheline_aligned(size_t, gfp_t, void **);
 extern void xpc_initiate_connect(int);
 extern void xpc_initiate_disconnect(int);
+extern enum xp_retval xpc_allocate_msg_wait(struct xpc_channel *);
 extern enum xp_retval xpc_initiate_allocate(short, int, u32, void **);
 extern enum xp_retval xpc_initiate_send(short, int, void *);
 extern enum xp_retval xpc_initiate_send_notify(short, int, void *,
@@ -680,6 +697,40 @@ extern void xpc_disconnect_channel(const
 extern void xpc_disconnect_callout(struct xpc_channel *, enum xp_retval);
 extern void xpc_partition_going_down(struct xpc_partition *, enum xp_retval);
 
+static inline int
+xpc_hb_allowed(short partid, void *heartbeating_to_mask)
+{
+	return test_bit(partid, heartbeating_to_mask);
+}
+
+static inline int
+xpc_any_hbs_allowed(void)
+{
+	DBUG_ON(xpc_heartbeating_to_mask == NULL);
+	return !bitmap_empty(xpc_heartbeating_to_mask, xp_max_npartitions);
+}
+
+static inline void
+xpc_allow_hb(short partid)
+{
+	DBUG_ON(xpc_heartbeating_to_mask == NULL);
+	set_bit(partid, xpc_heartbeating_to_mask);
+}
+
+static inline void
+xpc_disallow_hb(short partid)
+{
+	DBUG_ON(xpc_heartbeating_to_mask == NULL);
+	clear_bit(partid, xpc_heartbeating_to_mask);
+}
+
+static inline void
+xpc_disallow_all_hbs(void)
+{
+	DBUG_ON(xpc_heartbeating_to_mask == NULL);
+	bitmap_zero(xpc_heartbeating_to_mask, xp_max_npartitions);
+}
+
 static inline void
 xpc_wakeup_channel_mgr(struct xpc_partition *part)
 {
@@ -749,297 +800,7 @@ xpc_part_ref(struct xpc_partition *part)
 	}
 
 /*
- * This next set of inlines are used to keep track of when a partition is
- * potentially engaged in accessing memory belonging to another partition.
- */
-
-static inline void
-xpc_mark_partition_engaged(struct xpc_partition *part)
-{
-	unsigned long irq_flags;
-	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
-				   (XPC_ENGAGED_PARTITIONS_AMO *
-				    sizeof(AMO_t)));
-
-	local_irq_save(irq_flags);
-
-	/* set bit corresponding to our partid in remote partition's AMO */
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_OR,
-			 (1UL << sn_partition_id));
-	/*
-	 * We must always use the nofault function regardless of whether we
-	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
-	 * didn't, we'd never know that the other partition is down and would
-	 * keep sending IPIs and AMOs to it until the heartbeat times out.
-	 */
-	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
-							       variable),
-						     xp_nofault_PIOR_target));
-
-	local_irq_restore(irq_flags);
-}
-
-static inline void
-xpc_mark_partition_disengaged(struct xpc_partition *part)
-{
-	unsigned long irq_flags;
-	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
-				   (XPC_ENGAGED_PARTITIONS_AMO *
-				    sizeof(AMO_t)));
-
-	local_irq_save(irq_flags);
-
-	/* clear bit corresponding to our partid in remote partition's AMO */
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
-			 ~(1UL << sn_partition_id));
-	/*
-	 * We must always use the nofault function regardless of whether we
-	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
-	 * didn't, we'd never know that the other partition is down and would
-	 * keep sending IPIs and AMOs to it until the heartbeat times out.
-	 */
-	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
-							       variable),
-						     xp_nofault_PIOR_target));
-
-	local_irq_restore(irq_flags);
-}
-
-static inline void
-xpc_request_partition_disengage(struct xpc_partition *part)
-{
-	unsigned long irq_flags;
-	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
-				   (XPC_DISENGAGE_REQUEST_AMO * sizeof(AMO_t)));
-
-	local_irq_save(irq_flags);
-
-	/* set bit corresponding to our partid in remote partition's AMO */
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_OR,
-			 (1UL << sn_partition_id));
-	/*
-	 * We must always use the nofault function regardless of whether we
-	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
-	 * didn't, we'd never know that the other partition is down and would
-	 * keep sending IPIs and AMOs to it until the heartbeat times out.
-	 */
-	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
-							       variable),
-						     xp_nofault_PIOR_target));
-
-	local_irq_restore(irq_flags);
-}
-
-static inline void
-xpc_cancel_partition_disengage_request(struct xpc_partition *part)
-{
-	unsigned long irq_flags;
-	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
-				   (XPC_DISENGAGE_REQUEST_AMO * sizeof(AMO_t)));
-
-	local_irq_save(irq_flags);
-
-	/* clear bit corresponding to our partid in remote partition's AMO */
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
-			 ~(1UL << sn_partition_id));
-	/*
-	 * We must always use the nofault function regardless of whether we
-	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
-	 * didn't, we'd never know that the other partition is down and would
-	 * keep sending IPIs and AMOs to it until the heartbeat times out.
-	 */
-	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
-							       variable),
-						     xp_nofault_PIOR_target));
-
-	local_irq_restore(irq_flags);
-}
-
-static inline u64
-xpc_partition_engaged(u64 partid_mask)
-{
-	AMO_t *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
-
-	/* return our partition's AMO variable ANDed with partid_mask */
-	return (FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) &
-		partid_mask);
-}
-
-static inline u64
-xpc_partition_disengage_requested(u64 partid_mask)
-{
-	AMO_t *amo = xpc_vars->amos_page + XPC_DISENGAGE_REQUEST_AMO;
-
-	/* return our partition's AMO variable ANDed with partid_mask */
-	return (FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) &
-		partid_mask);
-}
-
-static inline void
-xpc_clear_partition_engaged(u64 partid_mask)
-{
-	AMO_t *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
-
-	/* clear bit(s) based on partid_mask in our partition's AMO */
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
-			 ~partid_mask);
-}
-
-static inline void
-xpc_clear_partition_disengage_request(u64 partid_mask)
-{
-	AMO_t *amo = xpc_vars->amos_page + XPC_DISENGAGE_REQUEST_AMO;
-
-	/* clear bit(s) based on partid_mask in our partition's AMO */
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
-			 ~partid_mask);
-}
-
-/*
- * The following set of macros and inlines are used for the sending and
- * receiving of IPIs (also known as IRQs). There are two flavors of IPIs,
- * one that is associated with partition activity (SGI_XPC_ACTIVATE) and
- * the other that is associated with channel activity (SGI_XPC_NOTIFY).
- */
-
-static inline u64
-xpc_IPI_receive(AMO_t *amo)
-{
-	return FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_CLEAR);
-}
-
-static inline enum xp_retval
-xpc_IPI_send(AMO_t *amo, u64 flag, int nasid, int phys_cpuid, int vector)
-{
-	int ret = 0;
-	unsigned long irq_flags;
-
-	local_irq_save(irq_flags);
-
-	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_OR, flag);
-	sn_send_IPI_phys(nasid, phys_cpuid, vector, 0);
-
-	/*
-	 * We must always use the nofault function regardless of whether we
-	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
-	 * didn't, we'd never know that the other partition is down and would
-	 * keep sending IPIs and AMOs to it until the heartbeat times out.
-	 */
-	ret = xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->variable),
-						     xp_nofault_PIOR_target));
-
-	local_irq_restore(irq_flags);
-
-	return ((ret == 0) ? xpSuccess : xpPioReadError);
-}
-
-/*
- * IPIs associated with SGI_XPC_ACTIVATE IRQ.
- */
-
-/*
- * Flag the appropriate AMO variable and send an IPI to the specified node.
- */
-static inline void
-xpc_activate_IRQ_send(u64 amos_page_pa, int from_nasid, int to_nasid,
-		      int to_phys_cpuid)
-{
-	int w_index = XPC_NASID_W_INDEX(from_nasid);
-	int b_index = XPC_NASID_B_INDEX(from_nasid);
-	AMO_t *amos = (AMO_t *)__va(amos_page_pa +
-				    (XPC_ACTIVATE_IRQ_AMOS * sizeof(AMO_t)));
-
-	(void)xpc_IPI_send(&amos[w_index], (1UL << b_index), to_nasid,
-			   to_phys_cpuid, SGI_XPC_ACTIVATE);
-}
-
-static inline void
-xpc_IPI_send_activate(struct xpc_vars *vars)
-{
-	xpc_activate_IRQ_send(vars->amos_page_pa, cnodeid_to_nasid(0),
-			      vars->act_nasid, vars->act_phys_cpuid);
-}
-
-static inline void
-xpc_IPI_send_activated(struct xpc_partition *part)
-{
-	xpc_activate_IRQ_send(part->remote_amos_page_pa, cnodeid_to_nasid(0),
-			      part->remote_act_nasid,
-			      part->remote_act_phys_cpuid);
-}
-
-static inline void
-xpc_IPI_send_reactivate(struct xpc_partition *part)
-{
-	xpc_activate_IRQ_send(xpc_vars->amos_page_pa, part->reactivate_nasid,
-			      xpc_vars->act_nasid, xpc_vars->act_phys_cpuid);
-}
-
-static inline void
-xpc_IPI_send_disengage(struct xpc_partition *part)
-{
-	xpc_activate_IRQ_send(part->remote_amos_page_pa, cnodeid_to_nasid(0),
-			      part->remote_act_nasid,
-			      part->remote_act_phys_cpuid);
-}
-
-/*
- * IPIs associated with SGI_XPC_NOTIFY IRQ.
- */
-
-/*
- * Send an IPI to the remote partition that is associated with the
- * specified channel.
- */
-#define XPC_NOTIFY_IRQ_SEND(_ch, _ipi_f, _irq_f) \
-		xpc_notify_IRQ_send(_ch, _ipi_f, #_ipi_f, _irq_f)
-
-static inline void
-xpc_notify_IRQ_send(struct xpc_channel *ch, u8 ipi_flag, char *ipi_flag_string,
-		    unsigned long *irq_flags)
-{
-	struct xpc_partition *part = &xpc_partitions[ch->partid];
-	enum xp_retval ret;
-
-	if (likely(part->act_state != XPC_P_DEACTIVATING)) {
-		ret = xpc_IPI_send(part->remote_IPI_amo_va,
-				   (u64)ipi_flag << (ch->number * 8),
-				   part->remote_IPI_nasid,
-				   part->remote_IPI_phys_cpuid, SGI_XPC_NOTIFY);
-		dev_dbg(xpc_chan, "%s sent to partid=%d, channel=%d, ret=%d\n",
-			ipi_flag_string, ch->partid, ch->number, ret);
-		if (unlikely(ret != xpSuccess)) {
-			if (irq_flags != NULL)
-				spin_unlock_irqrestore(&ch->lock, *irq_flags);
-			XPC_DEACTIVATE_PARTITION(part, ret);
-			if (irq_flags != NULL)
-				spin_lock_irqsave(&ch->lock, *irq_flags);
-		}
-	}
-}
-
-/*
- * Make it look like the remote partition, which is associated with the
- * specified channel, sent us an IPI. This faked IPI will be handled
- * by xpc_dropped_IPI_check().
- */
-#define XPC_NOTIFY_IRQ_SEND_LOCAL(_ch, _ipi_f) \
-		xpc_notify_IRQ_send_local(_ch, _ipi_f, #_ipi_f)
-
-static inline void
-xpc_notify_IRQ_send_local(struct xpc_channel *ch, u8 ipi_flag,
-			  char *ipi_flag_string)
-{
-	struct xpc_partition *part = &xpc_partitions[ch->partid];
-
-	FETCHOP_STORE_OP(TO_AMO((u64)&part->local_IPI_amo_va->variable),
-			 FETCHOP_OR, ((u64)ipi_flag << (ch->number * 8)));
-	dev_dbg(xpc_chan, "%s sent local from partid=%d, channel=%d\n",
-		ipi_flag_string, ch->partid, ch->number);
-}
-
-/*
- * The sending and receiving of IPIs includes the setting of an AMO variable
+ * The sending and receiving of IPIs includes the setting of an >>>AMO variable
  * to indicate the reason the IPI was sent. The 64-bit variable is divided
  * up into eight bytes, ordered from right to left. Byte zero pertains to
  * channel 0, byte one to channel 1, and so on. Each byte is described by
@@ -1052,107 +813,11 @@ xpc_notify_IRQ_send_local(struct xpc_cha
 #define	XPC_IPI_OPENREPLY	0x08
 #define	XPC_IPI_MSGREQUEST	0x10
 
-/* given an AMO variable and a channel#, get its associated IPI flags */
+/* given an >>>AMO variable and a channel#, get its associated IPI flags */
 #define XPC_GET_IPI_FLAGS(_amo, _c)	((u8) (((_amo) >> ((_c) * 8)) & 0xff))
 #define XPC_SET_IPI_FLAGS(_amo, _c, _f)	(_amo) |= ((u64) (_f) << ((_c) * 8))
 
 #define	XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(_amo) ((_amo) & 0x0f0f0f0f0f0f0f0fUL)
 #define XPC_ANY_MSG_IPI_FLAGS_SET(_amo)       ((_amo) & 0x1010101010101010UL)
 
-static inline void
-xpc_IPI_send_closerequest(struct xpc_channel *ch, unsigned long *irq_flags)
-{
-	struct xpc_openclose_args *args = ch->local_openclose_args;
-
-	args->reason = ch->reason;
-
-	XPC_NOTIFY_IRQ_SEND(ch, XPC_IPI_CLOSEREQUEST, irq_flags);
-}
-
-static inline void
-xpc_IPI_send_closereply(struct xpc_channel *ch, unsigned long *irq_flags)
-{
-	XPC_NOTIFY_IRQ_SEND(ch, XPC_IPI_CLOSEREPLY, irq_flags);
-}
-
-static inline void
-xpc_IPI_send_openrequest(struct xpc_channel *ch, unsigned long *irq_flags)
-{
-	struct xpc_openclose_args *args = ch->local_openclose_args;
-
-	args->msg_size = ch->msg_size;
-	args->local_nentries = ch->local_nentries;
-
-	XPC_NOTIFY_IRQ_SEND(ch, XPC_IPI_OPENREQUEST, irq_flags);
-}
-
-static inline void
-xpc_IPI_send_openreply(struct xpc_channel *ch, unsigned long *irq_flags)
-{
-	struct xpc_openclose_args *args = ch->local_openclose_args;
-
-	args->remote_nentries = ch->remote_nentries;
-	args->local_nentries = ch->local_nentries;
-	args->local_msgqueue_pa = __pa(ch->local_msgqueue);
-
-	XPC_NOTIFY_IRQ_SEND(ch, XPC_IPI_OPENREPLY, irq_flags);
-}
-
-static inline void
-xpc_IPI_send_msgrequest(struct xpc_channel *ch)
-{
-	XPC_NOTIFY_IRQ_SEND(ch, XPC_IPI_MSGREQUEST, NULL);
-}
-
-static inline void
-xpc_IPI_send_local_msgrequest(struct xpc_channel *ch)
-{
-	XPC_NOTIFY_IRQ_SEND_LOCAL(ch, XPC_IPI_MSGREQUEST);
-}
-
-/*
->>> this block comment needs to be moved and re-written.
- * Memory for XPC's AMO variables is allocated by the MSPEC driver. These
- * pages are located in the lowest granule. The lowest granule uses 4k pages
- * for cached references and an alternate TLB handler to never provide a
- * cacheable mapping for the entire region. This will prevent speculative
- * reading of cached copies of our lines from being issued which will cause
- * a PI FSB Protocol error to be generated by the SHUB. For XPC, we need 64
- * AMO variables (based on xp_max_npartitions) for message notification and an
- * additional 128 AMO variables (based on XP_NASID_MASK_WORDS) for partition
- * activation and 2 AMO variables for partition deactivation.
- */
-static inline AMO_t *
-xpc_IPI_init(int index)
-{
-	AMO_t *amo = xpc_vars->amos_page + index;
-
-	(void)xpc_IPI_receive(amo);	/* clear AMO variable */
-	return amo;
-}
-
-/*
- * Check to see if there is any channel activity to/from the specified
- * partition.
- */
-static inline void
-xpc_check_for_channel_activity(struct xpc_partition *part)
-{
-	u64 IPI_amo;
-	unsigned long irq_flags;
-
-	IPI_amo = xpc_IPI_receive(part->local_IPI_amo_va);
-	if (IPI_amo == 0)
-		return;
-
-	spin_lock_irqsave(&part->IPI_lock, irq_flags);
-	part->local_IPI_amo |= IPI_amo;
-	spin_unlock_irqrestore(&part->IPI_lock, irq_flags);
-
-	dev_dbg(xpc_chan, "received IPI from partid=%d, IPI_amo=0x%lx\n",
-		XPC_PARTID(part), IPI_amo);
-
-	xpc_wakeup_channel_mgr(part);
-}
-
 #endif /* _DRIVERS_MISC_SGIXP_XPC_H */
Index: linux-2.6/drivers/misc/sgi-xp/xpc_sn2.c
===================================================================
--- linux-2.6.orig/drivers/misc/sgi-xp/xpc_sn2.c	2008-05-28 07:03:09.420496138 -0500
+++ linux-2.6/drivers/misc/sgi-xp/xpc_sn2.c	2008-05-28 07:03:15.285225043 -0500
@@ -19,9 +19,370 @@
 #include <asm/sn/sn_sal.h>
 #include "xpc.h"
 
-struct xpc_vars *xpc_vars;
+static struct xpc_vars_sn2 *xpc_vars;	/* >>> Add _sn2 suffix? */
 static struct xpc_vars_part_sn2 *xpc_vars_part; /* >>> Add _sn2 suffix? */
 
+/*
+ * The following set of macros and functions are used for the sending and
+ * receiving of IPIs (also known as IRQs). There are two flavors of IPIs,
+ * one that is associated with partition activity (SGI_XPC_ACTIVATE) and
+ * the other that is associated with channel activity (SGI_XPC_NOTIFY).
+ */
+
+static u64
+xpc_IPI_receive_sn2(AMO_t *amo)
+{
+	return FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_CLEAR);
+}
+
+static enum xp_retval
+xpc_IPI_send_sn2(AMO_t *amo, u64 flag, int nasid, int phys_cpuid, int vector)
+{
+	int ret = 0;
+	unsigned long irq_flags;
+
+	local_irq_save(irq_flags);
+
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_OR, flag);
+	sn_send_IPI_phys(nasid, phys_cpuid, vector, 0);
+
+	/*
+	 * We must always use the nofault function regardless of whether we
+	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
+	 * didn't, we'd never know that the other partition is down and would
+	 * keep sending IPIs and AMOs to it until the heartbeat times out.
+	 */
+	ret = xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->variable),
+						     xp_nofault_PIOR_target));
+
+	local_irq_restore(irq_flags);
+
+	return ((ret == 0) ? xpSuccess : xpPioReadError);
+}
+
+static AMO_t *
+xpc_IPI_init_sn2(int index)
+{
+	AMO_t *amo = xpc_vars->amos_page + index;
+
+	(void)xpc_IPI_receive_sn2(amo);	/* clear AMO variable */
+	return amo;
+}
+
+/*
+ * IPIs associated with SGI_XPC_ACTIVATE IRQ.
+ */
+
+/*
+ * Flag the appropriate AMO variable and send an IPI to the specified node.
+ */
+static void
+xpc_activate_IRQ_send_sn2(u64 amos_page_pa, int from_nasid, int to_nasid,
+		      int to_phys_cpuid)
+{
+	int w_index = XPC_NASID_W_INDEX(from_nasid);
+	int b_index = XPC_NASID_B_INDEX(from_nasid);
+	AMO_t *amos = (AMO_t *)__va(amos_page_pa +
+				    (XPC_ACTIVATE_IRQ_AMOS * sizeof(AMO_t)));
+
+	(void)xpc_IPI_send_sn2(&amos[w_index], (1UL << b_index), to_nasid,
+			       to_phys_cpuid, SGI_XPC_ACTIVATE);
+}
+
+static void
+xpc_activate_IRQ_send_local_sn2(int from_nasid)
+{
+	int w_index = XPC_NASID_W_INDEX(from_nasid);
+	int b_index = XPC_NASID_B_INDEX(from_nasid);
+	AMO_t *amos = (AMO_t *)__va(xpc_vars->amos_page_pa +
+				    (XPC_ACTIVATE_IRQ_AMOS * sizeof(AMO_t)));
+
+	/* fake the sending and receipt of an activate IRQ from remote nasid */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amos[w_index].variable), FETCHOP_OR,
+			 (1UL << b_index));
+	atomic_inc(&xpc_act_IRQ_rcvd);
+	wake_up_interruptible(&xpc_act_IRQ_wq);
+}
+
+static void
+xpc_IPI_send_local_activate_sn2(int from_nasid)
+{
+	xpc_activate_IRQ_send_local_sn2(from_nasid);
+}
+
+static void
+xpc_IPI_send_activated_sn2(struct xpc_partition *part)
+{
+	xpc_activate_IRQ_send_sn2(part->remote_amos_page_pa,
+				  cnodeid_to_nasid(0), part->remote_act_nasid,
+				  part->remote_act_phys_cpuid);
+}
+
+static void
+xpc_IPI_send_local_reactivate_sn2(int from_nasid)
+{
+	xpc_activate_IRQ_send_local_sn2(from_nasid);
+}
+
+static void
+xpc_IPI_send_disengage_sn2(struct xpc_partition *part)
+{
+	xpc_activate_IRQ_send_sn2(part->remote_amos_page_pa,
+				  cnodeid_to_nasid(0), part->remote_act_nasid,
+				  part->remote_act_phys_cpuid);
+}
+
+/*
+ * IPIs associated with SGI_XPC_NOTIFY IRQ.
+ */
+
+/*
+ * Send an IPI to the remote partition that is associated with the
+ * specified channel.
+ */
+static void
+xpc_notify_IRQ_send_sn2(struct xpc_channel *ch, u8 ipi_flag,
+			char *ipi_flag_string, unsigned long *irq_flags)
+{
+	struct xpc_partition *part = &xpc_partitions[ch->partid];
+	enum xp_retval ret;
+
+	if (likely(part->act_state != XPC_P_DEACTIVATING)) {
+		ret = xpc_IPI_send_sn2(part->remote_IPI_amo_va,
+				       (u64)ipi_flag << (ch->number * 8),
+				       part->remote_IPI_nasid,
+				       part->remote_IPI_phys_cpuid,
+				       SGI_XPC_NOTIFY);
+		dev_dbg(xpc_chan, "%s sent to partid=%d, channel=%d, ret=%d\n",
+			ipi_flag_string, ch->partid, ch->number, ret);
+		if (unlikely(ret != xpSuccess)) {
+			if (irq_flags != NULL)
+				spin_unlock_irqrestore(&ch->lock, *irq_flags);
+			XPC_DEACTIVATE_PARTITION(part, ret);
+			if (irq_flags != NULL)
+				spin_lock_irqsave(&ch->lock, *irq_flags);
+		}
+	}
+}
+
+#define XPC_NOTIFY_IRQ_SEND_SN2(_ch, _ipi_f, _irq_f) \
+		xpc_notify_IRQ_send_sn2(_ch, _ipi_f, #_ipi_f, _irq_f)
+
+/*
+ * Make it look like the remote partition, which is associated with the
+ * specified channel, sent us an IPI. This faked IPI will be handled
+ * by xpc_dropped_IPI_check().
+ */
+static void
+xpc_notify_IRQ_send_local_sn2(struct xpc_channel *ch, u8 ipi_flag,
+			      char *ipi_flag_string)
+{
+	struct xpc_partition *part = &xpc_partitions[ch->partid];
+
+	FETCHOP_STORE_OP(TO_AMO((u64)&part->local_IPI_amo_va->variable),
+			 FETCHOP_OR, ((u64)ipi_flag << (ch->number * 8)));
+	dev_dbg(xpc_chan, "%s sent local from partid=%d, channel=%d\n",
+		ipi_flag_string, ch->partid, ch->number);
+}
+
+#define XPC_NOTIFY_IRQ_SEND_LOCAL_SN2(_ch, _ipi_f) \
+		xpc_notify_IRQ_send_local_sn2(_ch, _ipi_f, #_ipi_f)
+
+static void
+xpc_IPI_send_closerequest_sn2(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+	struct xpc_openclose_args *args = ch->local_openclose_args;
+
+	args->reason = ch->reason;
+	XPC_NOTIFY_IRQ_SEND_SN2(ch, XPC_IPI_CLOSEREQUEST, irq_flags);
+}
+
+static void
+xpc_IPI_send_closereply_sn2(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+	XPC_NOTIFY_IRQ_SEND_SN2(ch, XPC_IPI_CLOSEREPLY, irq_flags);
+}
+
+static void
+xpc_IPI_send_openrequest_sn2(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+	struct xpc_openclose_args *args = ch->local_openclose_args;
+
+	args->msg_size = ch->msg_size;
+	args->local_nentries = ch->local_nentries;
+	XPC_NOTIFY_IRQ_SEND_SN2(ch, XPC_IPI_OPENREQUEST, irq_flags);
+}
+
+static void
+xpc_IPI_send_openreply_sn2(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+	struct xpc_openclose_args *args = ch->local_openclose_args;
+
+	args->remote_nentries = ch->remote_nentries;
+	args->local_nentries = ch->local_nentries;
+	args->local_msgqueue_pa = __pa(ch->local_msgqueue);
+	XPC_NOTIFY_IRQ_SEND_SN2(ch, XPC_IPI_OPENREPLY, irq_flags);
+}
+
+static void
+xpc_IPI_send_msgrequest_sn2(struct xpc_channel *ch)
+{
+	XPC_NOTIFY_IRQ_SEND_SN2(ch, XPC_IPI_MSGREQUEST, NULL);
+}
+
+static void
+xpc_IPI_send_local_msgrequest_sn2(struct xpc_channel *ch)
+{
+	XPC_NOTIFY_IRQ_SEND_LOCAL_SN2(ch, XPC_IPI_MSGREQUEST);
+}
+
+/*
+ * This next set of functions are used to keep track of when a partition is
+ * potentially engaged in accessing memory belonging to another partition.
+ */
+
+static void
+xpc_mark_partition_engaged_sn2(struct xpc_partition *part)
+{
+	unsigned long irq_flags;
+	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
+				   (XPC_ENGAGED_PARTITIONS_AMO *
+				    sizeof(AMO_t)));
+
+	local_irq_save(irq_flags);
+
+	/* set bit corresponding to our partid in remote partition's AMO */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_OR,
+			 (1UL << sn_partition_id));
+	/*
+	 * We must always use the nofault function regardless of whether we
+	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
+	 * didn't, we'd never know that the other partition is down and would
+	 * keep sending IPIs and AMOs to it until the heartbeat times out.
+	 */
+	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
+							       variable),
+						     xp_nofault_PIOR_target));
+
+	local_irq_restore(irq_flags);
+}
+
+static void
+xpc_mark_partition_disengaged_sn2(struct xpc_partition *part)
+{
+	unsigned long irq_flags;
+	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
+				   (XPC_ENGAGED_PARTITIONS_AMO *
+				    sizeof(AMO_t)));
+
+	local_irq_save(irq_flags);
+
+	/* clear bit corresponding to our partid in remote partition's AMO */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
+			 ~(1UL << sn_partition_id));
+	/*
+	 * We must always use the nofault function regardless of whether we
+	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
+	 * didn't, we'd never know that the other partition is down and would
+	 * keep sending IPIs and AMOs to it until the heartbeat times out.
+	 */
+	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
+							       variable),
+						     xp_nofault_PIOR_target));
+
+	local_irq_restore(irq_flags);
+}
+
+static void
+xpc_request_partition_disengage_sn2(struct xpc_partition *part)
+{
+	unsigned long irq_flags;
+	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
+				   (XPC_DISENGAGE_REQUEST_AMO * sizeof(AMO_t)));
+
+	local_irq_save(irq_flags);
+
+	/* set bit corresponding to our partid in remote partition's AMO */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_OR,
+			 (1UL << sn_partition_id));
+	/*
+	 * We must always use the nofault function regardless of whether we
+	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
+	 * didn't, we'd never know that the other partition is down and would
+	 * keep sending IPIs and AMOs to it until the heartbeat times out.
+	 */
+	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
+							       variable),
+						     xp_nofault_PIOR_target));
+
+	local_irq_restore(irq_flags);
+}
+
+static void
+xpc_cancel_partition_disengage_request_sn2(struct xpc_partition *part)
+{
+	unsigned long irq_flags;
+	AMO_t *amo = (AMO_t *)__va(part->remote_amos_page_pa +
+				   (XPC_DISENGAGE_REQUEST_AMO * sizeof(AMO_t)));
+
+	local_irq_save(irq_flags);
+
+	/* clear bit corresponding to our partid in remote partition's AMO */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
+			 ~(1UL << sn_partition_id));
+	/*
+	 * We must always use the nofault function regardless of whether we
+	 * are on a Shub 1.1 system or a Shub 1.2 slice 0xc processor. If we
+	 * didn't, we'd never know that the other partition is down and would
+	 * keep sending IPIs and AMOs to it until the heartbeat times out.
+	 */
+	(void)xp_nofault_PIOR((u64 *)GLOBAL_MMR_ADDR(NASID_GET(&amo->
+							       variable),
+						     xp_nofault_PIOR_target));
+
+	local_irq_restore(irq_flags);
+}
+
+static u64
+xpc_partition_engaged_sn2(u64 partid_mask)
+{
+	AMO_t *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
+
+	/* return our partition's AMO variable ANDed with partid_mask */
+	return (FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) &
+		partid_mask);
+}
+
+static u64
+xpc_partition_disengage_requested_sn2(u64 partid_mask)
+{
+	AMO_t *amo = xpc_vars->amos_page + XPC_DISENGAGE_REQUEST_AMO;
+
+	/* return our partition's AMO variable ANDed with partid_mask */
+	return (FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) &
+		partid_mask);
+}
+
+static void
+xpc_clear_partition_engaged_sn2(u64 partid_mask)
+{
+	AMO_t *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
+
+	/* clear bit(s) based on partid_mask in our partition's AMO */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
+			 ~partid_mask);
+}
+
+static void
+xpc_clear_partition_disengage_request_sn2(u64 partid_mask)
+{
+	AMO_t *amo = xpc_vars->amos_page + XPC_DISENGAGE_REQUEST_AMO;
+
+	/* clear bit(s) based on partid_mask in our partition's AMO */
+	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
+			 ~partid_mask);
+}
+
 static enum xp_retval
 xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
 {
@@ -79,7 +440,7 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_p
 	}
 
 	/* clear xpc_vars */
-	memset(xpc_vars, 0, sizeof(struct xpc_vars));
+	memset(xpc_vars, 0, sizeof(struct xpc_vars_sn2));
 
 	xpc_vars->version = XPC_V_VERSION;
 	xpc_vars->act_nasid = cpuid_to_nasid(0);
@@ -94,15 +455,446 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_p
 
 	/* initialize the activate IRQ related AMO variables */
 	for (i = 0; i < xp_nasid_mask_words; i++)
-		(void)xpc_IPI_init(XPC_ACTIVATE_IRQ_AMOS + i);
+		(void)xpc_IPI_init_sn2(XPC_ACTIVATE_IRQ_AMOS + i);
 
 	/* initialize the engaged remote partitions related AMO variables */
-	(void)xpc_IPI_init(XPC_ENGAGED_PARTITIONS_AMO);
-	(void)xpc_IPI_init(XPC_DISENGAGE_REQUEST_AMO);
+	(void)xpc_IPI_init_sn2(XPC_ENGAGED_PARTITIONS_AMO);
+	(void)xpc_IPI_init_sn2(XPC_DISENGAGE_REQUEST_AMO);
+
+	return xpSuccess;
+}
+
+static void
+xpc_increment_heartbeat_sn2(void)
+{
+	xpc_vars->heartbeat++;
+}
+
+static void
+xpc_offline_heartbeat_sn2(void)
+{
+	xpc_increment_heartbeat_sn2();
+	xpc_vars->heartbeat_offline = 1;
+}
+
+static void
+xpc_online_heartbeat_sn2(void)
+{
+	xpc_increment_heartbeat_sn2();
+	xpc_vars->heartbeat_offline = 0;
+}
+
+static void
+xpc_heartbeat_init_sn2(void)
+{
+	DBUG_ON(xpc_vars == NULL);
+
+	bitmap_zero(xpc_vars->heartbeating_to_mask, XP_MAX_NPARTITIONS_SN2);
+	xpc_heartbeating_to_mask = &xpc_vars->heartbeating_to_mask[0];
+	xpc_online_heartbeat_sn2();
+}
+
+static void
+xpc_heartbeat_exit_sn2(void)
+{
+	xpc_offline_heartbeat_sn2();
+}
+
+/*
+ * At periodic intervals, scan through all active partitions and ensure
+ * their heartbeat is still active.  If not, the partition is deactivated.
+ */
+static void
+xpc_check_remote_hb_sn2(void)
+{
+	struct xpc_vars_sn2 *remote_vars;
+	struct xpc_partition *part;
+	short partid;
+	enum xp_retval ret;
+
+	remote_vars = (struct xpc_vars_sn2 *)xpc_remote_copy_buffer;
+
+	for (partid = 0; partid < xp_max_npartitions; partid++) {
+
+		if (xpc_exiting)
+			break;
+
+		if (partid == sn_partition_id)
+			continue;
+
+		part = &xpc_partitions[partid];
+
+		if (part->act_state == XPC_P_INACTIVE ||
+		    part->act_state == XPC_P_DEACTIVATING) {
+			continue;
+		}
+
+		/* pull the remote_hb cache line */
+		ret = xp_remote_memcpy(remote_vars,
+				       (void *)part->remote_vars_pa,
+				       XPC_RP_VARS_SIZE);
+		if (ret != xpSuccess) {
+			XPC_DEACTIVATE_PARTITION(part, ret);
+			continue;
+		}
+
+		dev_dbg(xpc_part, "partid = %d, heartbeat = %ld, last_heartbeat"
+			" = %ld, heartbeat_offline = %ld, HB_mask[0] = 0x%lx\n",
+			partid, remote_vars->heartbeat, part->last_heartbeat,
+			remote_vars->heartbeat_offline,
+			remote_vars->heartbeating_to_mask[0]);
+
+		if (((remote_vars->heartbeat == part->last_heartbeat) &&
+		     (remote_vars->heartbeat_offline == 0)) ||
+		    !xpc_hb_allowed(sn_partition_id,
+				    &remote_vars->heartbeating_to_mask)) {
+
+			XPC_DEACTIVATE_PARTITION(part, xpNoHeartbeat);
+			continue;
+		}
+
+		part->last_heartbeat = remote_vars->heartbeat;
+	}
+}
+
+/*
+ * Get a copy of the remote partition's XPC variables from the reserved page.
+ *
+ * remote_vars points to a buffer that is cacheline aligned for BTE copies and
+ * assumed to be of size XPC_RP_VARS_SIZE.
+ */
+static enum xp_retval
+xpc_get_remote_vars_sn2(u64 remote_vars_pa, struct xpc_vars_sn2 *remote_vars)
+{
+	enum xp_retval ret;
+
+	if (remote_vars_pa == 0)
+		return xpVarsNotSet;
+
+	/* pull over the cross partition variables */
+	ret = xp_remote_memcpy(remote_vars, (void *)remote_vars_pa,
+			       XPC_RP_VARS_SIZE);
+	if (ret != xpSuccess)
+		return ret;
+
+	if (XPC_VERSION_MAJOR(remote_vars->version) !=
+	    XPC_VERSION_MAJOR(XPC_V_VERSION)) {
+		return xpBadVersion;
+	}
 
 	return xpSuccess;
 }
 
+static void
+xpc_initiate_partition_activation_sn2(struct xpc_rsvd_page *remote_rp,
+				      u64 remote_rp_pa, int nasid)
+{
+	xpc_IPI_send_local_activate(nasid);
+}
+
+/*
+ * Update the remote partition's info.
+ */
+static void
+xpc_update_partition_info_sn2(struct xpc_partition *part, u8 remote_rp_version,
+			      struct timespec *remote_rp_stamp,
+			      u64 remote_rp_pa, u64 remote_vars_pa,
+			      struct xpc_vars_sn2 *remote_vars)
+{
+	part->remote_rp_version = remote_rp_version;
+	dev_dbg(xpc_part, "  remote_rp_version = 0x%016x\n",
+		part->remote_rp_version);
+
+	part->remote_rp_stamp = *remote_rp_stamp;
+	dev_dbg(xpc_part, "  remote_rp_stamp (tv_sec = 0x%lx tv_nsec = 0x%lx\n",
+		part->remote_rp_stamp.tv_sec, part->remote_rp_stamp.tv_nsec);
+
+	part->remote_rp_pa = remote_rp_pa;
+	dev_dbg(xpc_part, "  remote_rp_pa = 0x%016lx\n", part->remote_rp_pa);
+
+	part->remote_vars_pa = remote_vars_pa;
+	dev_dbg(xpc_part, "  remote_vars_pa = 0x%016lx\n",
+		part->remote_vars_pa);
+
+	part->last_heartbeat = remote_vars->heartbeat;
+	dev_dbg(xpc_part, "  last_heartbeat = 0x%016lx\n",
+		part->last_heartbeat);
+
+	part->remote_vars_part_pa = remote_vars->vars_part_pa;
+	dev_dbg(xpc_part, "  remote_vars_part_pa = 0x%016lx\n",
+		part->remote_vars_part_pa);
+
+	part->remote_act_nasid = remote_vars->act_nasid;
+	dev_dbg(xpc_part, "  remote_act_nasid = 0x%x\n",
+		part->remote_act_nasid);
+
+	part->remote_act_phys_cpuid = remote_vars->act_phys_cpuid;
+	dev_dbg(xpc_part, "  remote_act_phys_cpuid = 0x%x\n",
+		part->remote_act_phys_cpuid);
+
+	part->remote_amos_page_pa = remote_vars->amos_page_pa;
+	dev_dbg(xpc_part, "  remote_amos_page_pa = 0x%lx\n",
+		part->remote_amos_page_pa);
+
+	part->remote_vars_version = remote_vars->version;
+	dev_dbg(xpc_part, "  remote_vars_version = 0x%x\n",
+		part->remote_vars_version);
+}
+
+/*
+ * Prior code has determined the nasid which generated an IPI.  Inspect
+ * that nasid to determine if its partition needs to be activated or
+ * deactivated.
+ *
+ * A partition is consider "awaiting activation" if our partition
+ * flags indicate it is not active and it has a heartbeat.  A
+ * partition is considered "awaiting deactivation" if our partition
+ * flags indicate it is active but it has no heartbeat or it is not
+ * sending its heartbeat to us.
+ *
+ * To determine the heartbeat, the remote nasid must have a properly
+ * initialized reserved page.
+ */
+static void
+xpc_identify_act_IRQ_req_sn2(int nasid)
+{
+	struct xpc_rsvd_page *remote_rp;
+	struct xpc_vars_sn2 *remote_vars;
+	u64 remote_rp_pa;
+	u64 remote_vars_pa;
+	int remote_rp_version;
+	int reactivate = 0;
+	int stamp_diff;
+	struct timespec remote_rp_stamp = { 0, 0 }; /*>>> ZERO_STAMP */
+	short partid;
+	struct xpc_partition *part;
+	enum xp_retval ret;
+
+	/* pull over the reserved page structure */
+
+	remote_rp = (struct xpc_rsvd_page *)xpc_remote_copy_buffer;
+
+	ret = xpc_get_remote_rp(nasid, NULL, remote_rp, &remote_rp_pa);
+	if (ret != xpSuccess) {
+		dev_warn(xpc_part, "unable to get reserved page from nasid %d, "
+			 "which sent interrupt, reason=%d\n", nasid, ret);
+		return;
+	}
+
+	remote_vars_pa = remote_rp->sn.vars_pa;
+	remote_rp_version = remote_rp->version;
+	if (XPC_SUPPORTS_RP_STAMP(remote_rp_version))
+		remote_rp_stamp = remote_rp->stamp;
+
+	partid = remote_rp->SAL_partid;
+	part = &xpc_partitions[partid];
+
+	/* pull over the cross partition variables */
+
+	remote_vars = (struct xpc_vars_sn2 *)xpc_remote_copy_buffer;
+
+	ret = xpc_get_remote_vars_sn2(remote_vars_pa, remote_vars);
+	if (ret != xpSuccess) {
+
+		dev_warn(xpc_part, "unable to get XPC variables from nasid %d, "
+			 "which sent interrupt, reason=%d\n", nasid, ret);
+
+		XPC_DEACTIVATE_PARTITION(part, ret);
+		return;
+	}
+
+	part->act_IRQ_rcvd++;
+
+	dev_dbg(xpc_part, "partid for nasid %d is %d; IRQs = %d; HB = "
+		"%ld:0x%lx\n", (int)nasid, (int)partid, part->act_IRQ_rcvd,
+		remote_vars->heartbeat, remote_vars->heartbeating_to_mask[0]);
+
+	if (xpc_partition_disengaged(part) &&
+	    part->act_state == XPC_P_INACTIVE) {
+
+		xpc_update_partition_info_sn2(part, remote_rp_version,
+					      &remote_rp_stamp, remote_rp_pa,
+					      remote_vars_pa, remote_vars);
+
+		if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version)) {
+			if (xpc_partition_disengage_requested(1UL << partid)) {
+				/*
+				 * Other side is waiting on us to disengage,
+				 * even though we already have.
+				 */
+				return;
+			}
+
+		} else {
+			/* other side doesn't support disengage requests */
+			xpc_clear_partition_disengage_request(1UL << partid);
+		}
+
+		xpc_activate_partition(part);
+		return;
+	}
+
+	DBUG_ON(part->remote_rp_version == 0);
+	DBUG_ON(part->remote_vars_version == 0);
+
+	if (!XPC_SUPPORTS_RP_STAMP(part->remote_rp_version)) {
+		DBUG_ON(XPC_SUPPORTS_DISENGAGE_REQUEST(part->
+						       remote_vars_version));
+
+		if (!XPC_SUPPORTS_RP_STAMP(remote_rp_version)) {
+			DBUG_ON(XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->
+							       version));
+			/* see if the other side rebooted */
+			if (part->remote_amos_page_pa ==
+			    remote_vars->amos_page_pa &&
+			    xpc_hb_allowed(sn_partition_id,
+					  &remote_vars->heartbeating_to_mask)) {
+				/* doesn't look that way, so ignore the IPI */
+				return;
+			}
+		}
+
+		/*
+		 * Other side rebooted and previous XPC didn't support the
+		 * disengage request, so we don't need to do anything special.
+		 */
+
+		xpc_update_partition_info_sn2(part, remote_rp_version,
+					      &remote_rp_stamp, remote_rp_pa,
+					      remote_vars_pa, remote_vars);
+		part->reactivate_nasid = nasid;
+		XPC_DEACTIVATE_PARTITION(part, xpReactivating);
+		return;
+	}
+
+	DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version));
+
+	if (!XPC_SUPPORTS_RP_STAMP(remote_rp_version)) {
+		DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->version));
+
+		/*
+		 * Other side rebooted and previous XPC did support the
+		 * disengage request, but the new one doesn't.
+		 */
+
+		xpc_clear_partition_engaged(1UL << partid);
+		xpc_clear_partition_disengage_request(1UL << partid);
+
+		xpc_update_partition_info_sn2(part, remote_rp_version,
+					      &remote_rp_stamp, remote_rp_pa,
+					      remote_vars_pa, remote_vars);
+		reactivate = 1;
+
+	} else {
+		DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->version));
+
+		stamp_diff = xpc_compare_stamps(&part->remote_rp_stamp,
+						&remote_rp_stamp);
+		if (stamp_diff != 0) {
+			DBUG_ON(stamp_diff >= 0);
+
+			/*
+			 * Other side rebooted and the previous XPC did support
+			 * the disengage request, as does the new one.
+			 */
+
+			DBUG_ON(xpc_partition_engaged(1UL << partid));
+			DBUG_ON(xpc_partition_disengage_requested(1UL <<
+								  partid));
+
+			xpc_update_partition_info_sn2(part, remote_rp_version,
+						      &remote_rp_stamp,
+						      remote_rp_pa,
+						      remote_vars_pa,
+						      remote_vars);
+			reactivate = 1;
+		}
+	}
+
+	if (part->disengage_request_timeout > 0 &&
+	    !xpc_partition_disengaged(part)) {
+		/* still waiting on other side to disengage from us */
+		return;
+	}
+
+	if (reactivate) {
+		part->reactivate_nasid = nasid;
+		XPC_DEACTIVATE_PARTITION(part, xpReactivating);
+
+	} else if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version) &&
+		   xpc_partition_disengage_requested(1UL << partid)) {
+		XPC_DEACTIVATE_PARTITION(part, xpOtherGoingDown);
+	}
+}
+
+/*
+ * Loop through the activation AMO variables and process any bits
+ * which are set.  Each bit indicates a nasid sending a partition
+ * activation or deactivation request.
+ *
+ * Return #of IRQs detected.
+ */
+int
+xpc_identify_act_IRQ_sender_sn2(void)
+{
+	int word, bit;
+	u64 nasid_mask;
+	u64 nasid;		/* remote nasid */
+	int n_IRQs_detected = 0;
+	AMO_t *act_amos;
+
+	act_amos = xpc_vars->amos_page + XPC_ACTIVATE_IRQ_AMOS;
+
+	/* scan through act AMO variable looking for non-zero entries */
+	for (word = 0; word < xp_nasid_mask_words; word++) {
+
+		if (xpc_exiting)
+			break;
+
+		nasid_mask = xpc_IPI_receive_sn2(&act_amos[word]);
+		if (nasid_mask == 0) {
+			/* no IRQs from nasids in this variable */
+			continue;
+		}
+
+		dev_dbg(xpc_part, "AMO[%d] gave back 0x%lx\n", word,
+			nasid_mask);
+
+		/*
+		 * If this nasid has been added to the machine since
+		 * our partition was reset, this will retain the
+		 * remote nasid in our reserved pages machine mask.
+		 * This is used in the event of module reload.
+		 */
+		xpc_mach_nasids[word] |= nasid_mask;
+
+		/* locate the nasid(s) which sent interrupts */
+
+		for (bit = 0; bit < (8 * sizeof(u64)); bit++) {
+			if (nasid_mask & (1UL << bit)) {
+				n_IRQs_detected++;
+				nasid = XPC_NASID_FROM_W_B(word, bit);
+				dev_dbg(xpc_part, "interrupt from nasid %ld\n",
+					nasid);
+				xpc_identify_act_IRQ_req_sn2(nasid);
+			}
+		}
+	}
+	return n_IRQs_detected;
+}
+
+static void
+xpc_process_act_IRQ_rcvd_sn2(int n_IRQs_expected)
+{
+	int n_IRQs_detected;
+
+	n_IRQs_detected = xpc_identify_act_IRQ_sender_sn2();
+	if (n_IRQs_detected < n_IRQs_expected) {
+		/* retry once to help avoid missing AMO */
+		(void)xpc_identify_act_IRQ_sender_sn2();
+	}
+}
+
 /*
  * Setup the infrastructure necessary to support XPartition Communication
  * between the specified remote partition and the local one.
@@ -177,7 +969,7 @@ xpc_setup_infrastructure_sn2(struct xpc_
 
 	part->remote_openclose_args_pa = 0;
 
-	part->local_IPI_amo_va = xpc_IPI_init(partid);
+	part->local_IPI_amo_va = xpc_IPI_init_sn2(partid);
 	part->local_IPI_amo = 0;
 	spin_lock_init(&part->IPI_lock);
 
@@ -468,6 +1260,28 @@ xpc_make_first_contact_sn2(struct xpc_pa
 {
 	enum xp_retval ret;
 
+	/*
+	 * Register the remote partition's AMOs with SAL so it can handle
+	 * and cleanup errors within that address range should the remote
+	 * partition go down. We don't unregister this range because it is
+	 * difficult to tell when outstanding writes to the remote partition
+	 * are finished and thus when it is safe to unregister. This should
+	 * not result in wasted space in the SAL xp_addr_region table because
+	 * we should get the same page for remote_amos_page_pa after module
+	 * reloads and system reboots.
+	 */
+	if (sn_register_xp_addr_region(part->remote_amos_page_pa,
+				       PAGE_SIZE, 1) < 0) {
+		dev_warn(xpc_part, "xpc_activating(%d) failed to register "
+			 "xp_addr region\n", XPC_PARTID(part));
+
+		ret = xpPhysAddrRegFailed;
+		XPC_DEACTIVATE_PARTITION(part, ret);
+		return ret;
+	}
+
+	xpc_IPI_send_activated(part);
+
 	while ((ret = xpc_pull_remote_vars_part_sn2(part)) != xpSuccess) {
 		if (ret != xpRetry) {
 			XPC_DEACTIVATE_PARTITION(part, ret);
@@ -651,15 +1465,370 @@ xpc_get_deliverable_msg_sn2(struct xpc_c
 	return msg;
 }
 
+/*
+ * 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_sn2(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 == 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(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_sn2(ch);
+}
+
+/*
+ * Allocate an entry for a message from the message queue associated with the
+ * specified channel.
+ */
+static enum xp_retval
+xpc_allocate_msg_sn2(struct xpc_channel *ch, u32 flags,
+		     struct xpc_msg **address_of_msg)
+{
+	struct xpc_msg *msg;
+	enum xp_retval ret;
+	s64 put;
+
+	/* this reference will be dropped in xpc_send_msg_sn2() */
+	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 xpNotConnected;
+	}
+
+	/*
+	 * 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 = xpTimeout;
+
+	while (1) {
+
+		put = ch->w_local_GP.put;
+		rmb();	/* guarantee that .put loads before .get */
+		if (put - 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 == xpTimeout)
+			xpc_IPI_send_local_msgrequest_sn2(ch);
+
+		if (flags & XPC_NOWAIT) {
+			xpc_msgqueue_deref(ch);
+			return xpNoWait;
+		}
+
+		ret = xpc_allocate_msg_wait(ch);
+		if (ret != xpInterrupted && ret != xpTimeout) {
+			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 xpSuccess;
+}
+
+/*
+ * 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 xp_retval
+xpc_send_msg_sn2(struct xpc_channel *ch, struct xpc_msg *msg, u8 notify_type,
+		 xpc_notify_func func, void *key)
+{
+	enum xp_retval ret = xpSuccess;
+	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_sn2() */
+		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(&notify->type, notify_type, 0) ==
+			    notify_type) {
+				atomic_dec(&ch->n_to_notify);
+				ret = ch->reason;
+			}
+
+			/* drop reference grabbed in xpc_allocate_msg_sn2() */
+			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_sn2(ch, put);
+
+	/* drop the reference grabbed in xpc_allocate_msg_sn2() */
+	xpc_msgqueue_deref(ch);
+	return ret;
+}
+
+/*
+ * 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_sn2(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 == 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(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_sn2(ch);
+}
+
+static void
+xpc_received_msg_sn2(struct xpc_channel *ch, struct xpc_msg *msg)
+{
+	s64 get;
+	s64 msg_number = msg->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_sn2(ch, get, msg->flags);
+}
+
 void
 xpc_init_sn2(void)
 {
 	xpc_rsvd_page_init = xpc_rsvd_page_init_sn2;
+	xpc_increment_heartbeat = xpc_increment_heartbeat_sn2;
+	xpc_offline_heartbeat = xpc_offline_heartbeat_sn2;
+	xpc_online_heartbeat = xpc_online_heartbeat_sn2;
+	xpc_heartbeat_init = xpc_heartbeat_init_sn2;
+	xpc_heartbeat_exit = xpc_heartbeat_exit_sn2;
+	xpc_check_remote_hb = xpc_check_remote_hb_sn2;
+
+	xpc_initiate_partition_activation =
+	    xpc_initiate_partition_activation_sn2;
+	xpc_process_act_IRQ_rcvd = xpc_process_act_IRQ_rcvd_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;
+
+	xpc_mark_partition_engaged = xpc_mark_partition_engaged_sn2;
+	xpc_mark_partition_disengaged = xpc_mark_partition_disengaged_sn2;
+	xpc_request_partition_disengage = xpc_request_partition_disengage_sn2;
+	xpc_cancel_partition_disengage_request =
+	    xpc_cancel_partition_disengage_request_sn2;
+	xpc_partition_engaged = xpc_partition_engaged_sn2;
+	xpc_partition_disengage_requested =
+	    xpc_partition_disengage_requested_sn2;
+	xpc_clear_partition_engaged = xpc_clear_partition_engaged_sn2;
+	xpc_clear_partition_disengage_request =
+	    xpc_clear_partition_disengage_request_sn2;
+
+	xpc_IPI_send_local_activate = xpc_IPI_send_local_activate_sn2;
+	xpc_IPI_send_activated = xpc_IPI_send_activated_sn2;
+	xpc_IPI_send_local_reactivate = xpc_IPI_send_local_reactivate_sn2;
+	xpc_IPI_send_disengage = xpc_IPI_send_disengage_sn2;
+
+	xpc_IPI_send_closerequest = xpc_IPI_send_closerequest_sn2;
+	xpc_IPI_send_closereply = xpc_IPI_send_closereply_sn2;
+	xpc_IPI_send_openrequest = xpc_IPI_send_openrequest_sn2;
+	xpc_IPI_send_openreply = xpc_IPI_send_openreply_sn2;
+
+	xpc_allocate_msg = xpc_allocate_msg_sn2;
+
+	xpc_send_msg = xpc_send_msg_sn2;
+	xpc_received_msg = xpc_received_msg_sn2;
 }
 
 void
Index: linux-2.6/drivers/misc/sgi-xp/xpc_partition.c
===================================================================
--- linux-2.6.orig/drivers/misc/sgi-xp/xpc_partition.c	2008-05-28 07:03:09.332485199 -0500
+++ linux-2.6/drivers/misc/sgi-xp/xpc_partition.c	2008-05-28 07:03:15.309228026 -0500
@@ -42,7 +42,7 @@ u64 xpc_prot_vec[MAX_NUMNODES];
 /* this partition's reserved page pointers */
 struct xpc_rsvd_page *xpc_rsvd_page;
 static u64 *xpc_part_nasids;
-static u64 *xpc_mach_nasids;
+u64 *xpc_mach_nasids;
 
 /* >>> next two variables should be 'xpc_' if they remain here */
 static int xp_sizeof_nasid_mask;	/* actual size in bytes of nasid mask */
@@ -318,69 +318,13 @@ xpc_restrict_IPI_ops(void)
 }
 
 /*
- * At periodic intervals, scan through all active partitions and ensure
- * their heartbeat is still active.  If not, the partition is deactivated.
- */
-void
-xpc_check_remote_hb(void)
-{
-	struct xpc_vars *remote_vars;
-	struct xpc_partition *part;
-	short partid;
-	enum xp_retval ret;
-
-	remote_vars = (struct xpc_vars *)xpc_remote_copy_buffer;
-
-	for (partid = 0; partid < xp_max_npartitions; partid++) {
-
-		if (xpc_exiting)
-			break;
-
-		if (partid == sn_partition_id)
-			continue;
-
-		part = &xpc_partitions[partid];
-
-		if (part->act_state == XPC_P_INACTIVE ||
-		    part->act_state == XPC_P_DEACTIVATING) {
-			continue;
-		}
-
-		/* pull the remote_hb cache line */
-		ret = xp_remote_memcpy(remote_vars,
-				       (void *)part->remote_vars_pa,
-				       XPC_RP_VARS_SIZE);
-		if (ret != xpSuccess) {
-			XPC_DEACTIVATE_PARTITION(part, ret);
-			continue;
-		}
-
-		dev_dbg(xpc_part, "partid = %d, heartbeat = %ld, last_heartbeat"
-			" = %ld, heartbeat_offline = %ld, HB_mask = 0x%lx\n",
-			partid, remote_vars->heartbeat, part->last_heartbeat,
-			remote_vars->heartbeat_offline,
-			remote_vars->heartbeating_to_mask);
-
-		if (((remote_vars->heartbeat == part->last_heartbeat) &&
-		     (remote_vars->heartbeat_offline == 0)) ||
-		    !xpc_hb_allowed(sn_partition_id, remote_vars)) {
-
-			XPC_DEACTIVATE_PARTITION(part, xpNoHeartbeat);
-			continue;
-		}
-
-		part->last_heartbeat = remote_vars->heartbeat;
-	}
-}
-
-/*
  * Get a copy of a portion of the remote partition's rsvd page.
  *
  * remote_rp points to a buffer that is cacheline aligned for BTE copies and
  * is large enough to contain a copy of their reserved page header and
  * part_nasids mask.
  */
-static enum xp_retval
+enum xp_retval
 xpc_get_remote_rp(int nasid, u64 *discovered_nasids,
 		  struct xpc_rsvd_page *remote_rp, u64 *remote_rp_pa)
 {
@@ -432,322 +376,6 @@ xpc_get_remote_rp(int nasid, u64 *discov
 }
 
 /*
- * Get a copy of the remote partition's XPC variables from the reserved page.
- *
- * remote_vars points to a buffer that is cacheline aligned for BTE copies and
- * assumed to be of size XPC_RP_VARS_SIZE.
- */
-static enum xp_retval
-xpc_get_remote_vars(u64 remote_vars_pa, struct xpc_vars *remote_vars)
-{
-	enum xp_retval ret;
-
-	if (remote_vars_pa == 0)
-		return xpVarsNotSet;
-
-	/* pull over the cross partition variables */
-	ret = xp_remote_memcpy(remote_vars, (void *)remote_vars_pa,
-			       XPC_RP_VARS_SIZE);
-	if (ret != xpSuccess)
-		return ret;
-
-	if (XPC_VERSION_MAJOR(remote_vars->version) !=
-	    XPC_VERSION_MAJOR(XPC_V_VERSION)) {
-		return xpBadVersion;
-	}
-
-	return xpSuccess;
-}
-
-/*
- * Update the remote partition's info.
- */
-static void
-xpc_update_partition_info(struct xpc_partition *part, u8 remote_rp_version,
-			  struct timespec *remote_rp_stamp, u64 remote_rp_pa,
-			  u64 remote_vars_pa, struct xpc_vars *remote_vars)
-{
-	part->remote_rp_version = remote_rp_version;
-	dev_dbg(xpc_part, "  remote_rp_version = 0x%016x\n",
-		part->remote_rp_version);
-
-	part->remote_rp_stamp = *remote_rp_stamp;
-	dev_dbg(xpc_part, "  remote_rp_stamp (tv_sec = 0x%lx tv_nsec = 0x%lx\n",
-		part->remote_rp_stamp.tv_sec, part->remote_rp_stamp.tv_nsec);
-
-	part->remote_rp_pa = remote_rp_pa;
-	dev_dbg(xpc_part, "  remote_rp_pa = 0x%016lx\n", part->remote_rp_pa);
-
-	part->remote_vars_pa = remote_vars_pa;
-	dev_dbg(xpc_part, "  remote_vars_pa = 0x%016lx\n",
-		part->remote_vars_pa);
-
-	part->last_heartbeat = remote_vars->heartbeat;
-	dev_dbg(xpc_part, "  last_heartbeat = 0x%016lx\n",
-		part->last_heartbeat);
-
-/* >>> remote_vars_part_pa and vars_part_pa are sn2 only!!! */
-	part->remote_vars_part_pa = remote_vars->vars_part_pa;
-	dev_dbg(xpc_part, "  remote_vars_part_pa = 0x%016lx\n",
-		part->remote_vars_part_pa);
-
-	part->remote_act_nasid = remote_vars->act_nasid;
-	dev_dbg(xpc_part, "  remote_act_nasid = 0x%x\n",
-		part->remote_act_nasid);
-
-	part->remote_act_phys_cpuid = remote_vars->act_phys_cpuid;
-	dev_dbg(xpc_part, "  remote_act_phys_cpuid = 0x%x\n",
-		part->remote_act_phys_cpuid);
-
-	part->remote_amos_page_pa = remote_vars->amos_page_pa;
-	dev_dbg(xpc_part, "  remote_amos_page_pa = 0x%lx\n",
-		part->remote_amos_page_pa);
-
-	part->remote_vars_version = remote_vars->version;
-	dev_dbg(xpc_part, "  remote_vars_version = 0x%x\n",
-		part->remote_vars_version);
-}
-
-/*
- * Prior code has determined the nasid which generated an IPI.  Inspect
- * that nasid to determine if its partition needs to be activated or
- * deactivated.
- *
- * A partition is consider "awaiting activation" if our partition
- * flags indicate it is not active and it has a heartbeat.  A
- * partition is considered "awaiting deactivation" if our partition
- * flags indicate it is active but it has no heartbeat or it is not
- * sending its heartbeat to us.
- *
- * To determine the heartbeat, the remote nasid must have a properly
- * initialized reserved page.
- */
-static void
-xpc_identify_act_IRQ_req(int nasid)
-{
-	struct xpc_rsvd_page *remote_rp;
-	struct xpc_vars *remote_vars;
-	u64 remote_rp_pa;
-	u64 remote_vars_pa;
-	int remote_rp_version;
-	int reactivate = 0;
-	int stamp_diff;
-	struct timespec remote_rp_stamp = { 0, 0 }; /*>>> ZERO_STAMP */
-	short partid;
-	struct xpc_partition *part;
-	enum xp_retval ret;
-
-	/* pull over the reserved page structure */
-
-	remote_rp = (struct xpc_rsvd_page *)xpc_remote_copy_buffer;
-
-	ret = xpc_get_remote_rp(nasid, NULL, remote_rp, &remote_rp_pa);
-	if (ret != xpSuccess) {
-		dev_warn(xpc_part, "unable to get reserved page from nasid %d, "
-			 "which sent interrupt, reason=%d\n", nasid, ret);
-		return;
-	}
-
-	remote_vars_pa = remote_rp->sn.vars_pa;
-	remote_rp_version = remote_rp->version;
-	if (XPC_SUPPORTS_RP_STAMP(remote_rp_version))
-		remote_rp_stamp = remote_rp->stamp;
-
-	partid = remote_rp->SAL_partid;
-	part = &xpc_partitions[partid];
-
-	/* pull over the cross partition variables */
-
-	remote_vars = (struct xpc_vars *)xpc_remote_copy_buffer;
-
-	ret = xpc_get_remote_vars(remote_vars_pa, remote_vars);
-	if (ret != xpSuccess) {
-
-		dev_warn(xpc_part, "unable to get XPC variables from nasid %d, "
-			 "which sent interrupt, reason=%d\n", nasid, ret);
-
-		XPC_DEACTIVATE_PARTITION(part, ret);
-		return;
-	}
-
-	part->act_IRQ_rcvd++;
-
-	dev_dbg(xpc_part, "partid for nasid %d is %d; IRQs = %d; HB = "
-		"%ld:0x%lx\n", (int)nasid, (int)partid, part->act_IRQ_rcvd,
-		remote_vars->heartbeat, remote_vars->heartbeating_to_mask);
-
-	if (xpc_partition_disengaged(part) &&
-	    part->act_state == XPC_P_INACTIVE) {
-
-		xpc_update_partition_info(part, remote_rp_version,
-					  &remote_rp_stamp, remote_rp_pa,
-					  remote_vars_pa, remote_vars);
-
-		if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version)) {
-			if (xpc_partition_disengage_requested(1UL << partid)) {
-				/*
-				 * Other side is waiting on us to disengage,
-				 * even though we already have.
-				 */
-				return;
-			}
-		} else {
-			/* other side doesn't support disengage requests */
-			xpc_clear_partition_disengage_request(1UL << partid);
-		}
-
-		xpc_activate_partition(part);
-		return;
-	}
-
-	DBUG_ON(part->remote_rp_version == 0);
-	DBUG_ON(part->remote_vars_version == 0);
-
-	if (!XPC_SUPPORTS_RP_STAMP(part->remote_rp_version)) {
-		DBUG_ON(XPC_SUPPORTS_DISENGAGE_REQUEST(part->
-						       remote_vars_version));
-
-		if (!XPC_SUPPORTS_RP_STAMP(remote_rp_version)) {
-			DBUG_ON(XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->
-							       version));
-			/* see if the other side rebooted */
-			if (part->remote_amos_page_pa ==
-			    remote_vars->amos_page_pa &&
-			    xpc_hb_allowed(sn_partition_id, remote_vars)) {
-				/* doesn't look that way, so ignore the IPI */
-				return;
-			}
-		}
-
-		/*
-		 * Other side rebooted and previous XPC didn't support the
-		 * disengage request, so we don't need to do anything special.
-		 */
-
-		xpc_update_partition_info(part, remote_rp_version,
-					  &remote_rp_stamp, remote_rp_pa,
-					  remote_vars_pa, remote_vars);
-		part->reactivate_nasid = nasid;
-		XPC_DEACTIVATE_PARTITION(part, xpReactivating);
-		return;
-	}
-
-	DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version));
-
-	if (!XPC_SUPPORTS_RP_STAMP(remote_rp_version)) {
-		DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->version));
-
-		/*
-		 * Other side rebooted and previous XPC did support the
-		 * disengage request, but the new one doesn't.
-		 */
-
-		xpc_clear_partition_engaged(1UL << partid);
-		xpc_clear_partition_disengage_request(1UL << partid);
-
-		xpc_update_partition_info(part, remote_rp_version,
-					  &remote_rp_stamp, remote_rp_pa,
-					  remote_vars_pa, remote_vars);
-		reactivate = 1;
-
-	} else {
-		DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->version));
-
-		stamp_diff = xpc_compare_stamps(&part->remote_rp_stamp,
-						&remote_rp_stamp);
-		if (stamp_diff != 0) {
-			DBUG_ON(stamp_diff >= 0);
-
-			/*
-			 * Other side rebooted and the previous XPC did support
-			 * the disengage request, as does the new one.
-			 */
-
-			DBUG_ON(xpc_partition_engaged(1UL << partid));
-			DBUG_ON(xpc_partition_disengage_requested(1UL <<
-								  partid));
-
-			xpc_update_partition_info(part, remote_rp_version,
-						  &remote_rp_stamp,
-						  remote_rp_pa, remote_vars_pa,
-						  remote_vars);
-			reactivate = 1;
-		}
-	}
-
-	if (part->disengage_request_timeout > 0 &&
-	    !xpc_partition_disengaged(part)) {
-		/* still waiting on other side to disengage from us */
-		return;
-	}
-
-	if (reactivate) {
-		part->reactivate_nasid = nasid;
-		XPC_DEACTIVATE_PARTITION(part, xpReactivating);
-
-	} else if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version) &&
-		   xpc_partition_disengage_requested(1UL << partid)) {
-		XPC_DEACTIVATE_PARTITION(part, xpOtherGoingDown);
-	}
-}
-
-/*
- * Loop through the activation AMO variables and process any bits
- * which are set.  Each bit indicates a nasid sending a partition
- * activation or deactivation request.
- *
- * Return #of IRQs detected.
- */
-int
-xpc_identify_act_IRQ_sender(void)
-{
-	int word, bit;
-	u64 nasid_mask;
-	u64 nasid;		/* remote nasid */
-	int n_IRQs_detected = 0;
-	AMO_t *act_amos;
-
-	act_amos = xpc_vars->amos_page + XPC_ACTIVATE_IRQ_AMOS;
-
-	/* scan through act AMO variable looking for non-zero entries */
-	for (word = 0; word < xp_nasid_mask_words; word++) {
-
-		if (xpc_exiting)
-			break;
-
-		nasid_mask = xpc_IPI_receive(&act_amos[word]);
-		if (nasid_mask == 0) {
-			/* no IRQs from nasids in this variable */
-			continue;
-		}
-
-		dev_dbg(xpc_part, "AMO[%d] gave back 0x%lx\n", word,
-			nasid_mask);
-
-		/*
-		 * If this nasid has been added to the machine since
-		 * our partition was reset, this will retain the
-		 * remote nasid in our reserved pages machine mask.
-		 * This is used in the event of module reload.
-		 */
-		xpc_mach_nasids[word] |= nasid_mask;
-
-		/* locate the nasid(s) which sent interrupts */
-
-		for (bit = 0; bit < (8 * sizeof(u64)); bit++) {
-			if (nasid_mask & (1UL << bit)) {
-				n_IRQs_detected++;
-				nasid = XPC_NASID_FROM_W_B(word, bit);
-				dev_dbg(xpc_part, "interrupt from nasid %ld\n",
-					nasid);
-				xpc_identify_act_IRQ_req(nasid);
-			}
-		}
-	}
-	return n_IRQs_detected;
-}
-
-/*
  * See if the other side has responded to a partition disengage request
  * from us.
  */
@@ -836,7 +464,7 @@ xpc_deactivate_partition(const int line,
 		spin_unlock_irqrestore(&part->act_lock, irq_flags);
 		if (reason == xpReactivating) {
 			/* we interrupt ourselves to reactivate partition */
-			xpc_IPI_send_reactivate(part);
+			xpc_IPI_send_local_reactivate(part->reactivate_nasid);
 		}
 		return;
 	}
@@ -903,16 +531,12 @@ xpc_discovery(void)
 {
 	void *remote_rp_base;
 	struct xpc_rsvd_page *remote_rp;
-	struct xpc_vars *remote_vars;
 	u64 remote_rp_pa;
-	u64 remote_vars_pa;
 	int region;
 	int region_size;
 	int max_regions;
 	int nasid;
 	struct xpc_rsvd_page *rp;
-	short partid;
-	struct xpc_partition *part;
 	u64 *discovered_nasids;
 	enum xp_retval ret;
 
@@ -922,8 +546,6 @@ xpc_discovery(void)
 	if (remote_rp == NULL)
 		return;
 
-	remote_vars = (struct xpc_vars *)remote_rp;
-
 	discovered_nasids = kzalloc(sizeof(u64) * xp_nasid_mask_words,
 				    GFP_KERNEL);
 	if (discovered_nasids == NULL) {
@@ -988,7 +610,7 @@ xpc_discovery(void)
 				continue;
 			}
 
-			/* pull over the reserved page structure */
+			/* pull over the rsvd page header & part_nasids mask */
 
 			ret = xpc_get_remote_rp(nasid, discovered_nasids,
 						remote_rp, &remote_rp_pa);
@@ -1003,72 +625,8 @@ xpc_discovery(void)
 				continue;
 			}
 
-			remote_vars_pa = remote_rp->sn.vars_pa;
-
-			partid = remote_rp->SAL_partid;
-			part = &xpc_partitions[partid];
-
-			/* pull over the cross partition variables */
-
-			ret = xpc_get_remote_vars(remote_vars_pa, remote_vars);
-			if (ret != xpSuccess) {
-				dev_dbg(xpc_part, "unable to get XPC variables "
-					"from nasid %d, reason=%d\n", nasid,
-					ret);
-
-				XPC_DEACTIVATE_PARTITION(part, ret);
-				continue;
-			}
-
-			if (part->act_state != XPC_P_INACTIVE) {
-				dev_dbg(xpc_part, "partition %d on nasid %d is "
-					"already activating\n", partid, nasid);
-				break;
-			}
-
-			/*
-			 * Register the remote partition's AMOs with SAL so it
-			 * can handle and cleanup errors within that address
-			 * range should the remote partition go down. We don't
-			 * unregister this range because it is difficult to
-			 * tell when outstanding writes to the remote partition
-			 * are finished and thus when it is thus safe to
-			 * unregister. This should not result in wasted space
-			 * in the SAL xp_addr_region table because we should
-			 * get the same page for remote_act_amos_pa after
-			 * module reloads and system reboots.
-			 */
-			if (sn_register_xp_addr_region
-			    (remote_vars->amos_page_pa, PAGE_SIZE, 1) < 0) {
-				dev_dbg(xpc_part,
-					"partition %d failed to "
-					"register xp_addr region 0x%016lx\n",
-					partid, remote_vars->amos_page_pa);
-
-				XPC_SET_REASON(part, xpPhysAddrRegFailed,
-					       __LINE__);
-				break;
-			}
-
-			/*
-			 * The remote nasid is valid and available.
-			 * Send an interrupt to that nasid to notify
-			 * it that we are ready to begin activation.
-			 */
-			dev_dbg(xpc_part, "sending an interrupt to AMO 0x%lx, "
-				"nasid %d, phys_cpuid 0x%x\n",
-				remote_vars->amos_page_pa,
-				remote_vars->act_nasid,
-				remote_vars->act_phys_cpuid);
-
-			if (XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->
-							   version)) {
-				part->remote_amos_page_pa =
-				    remote_vars->amos_page_pa;
-				xpc_mark_partition_disengaged(part);
-				xpc_cancel_partition_disengage_request(part);
-			}
-			xpc_IPI_send_activate(remote_vars);
+			xpc_initiate_partition_activation(remote_rp,
+							  remote_rp_pa, nasid);
 		}
 	}
 
Index: linux-2.6/drivers/misc/sgi-xp/xpc_main.c
===================================================================
--- linux-2.6.orig/drivers/misc/sgi-xp/xpc_main.c	2008-05-28 07:03:09.400493652 -0500
+++ linux-2.6/drivers/misc/sgi-xp/xpc_main.c	2008-05-28 07:03:15.329230512 -0500
@@ -148,12 +148,14 @@ static struct ctl_table_header *xpc_sysc
 int xpc_disengage_request_timedout;
 
 /* #of IRQs received */
-static atomic_t xpc_act_IRQ_rcvd;
+atomic_t xpc_act_IRQ_rcvd;
 
 /* IRQ handler notifies this wait queue on receipt of an IRQ */
-static DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq);
+DECLARE_WAIT_QUEUE_HEAD(xpc_act_IRQ_wq);
 
 static unsigned long xpc_hb_check_timeout;
+static struct timer_list xpc_hb_timer;
+void *xpc_heartbeating_to_mask;
 
 /* notification that the xpc_hb_checker thread has exited */
 static DECLARE_COMPLETION(xpc_hb_checker_exited);
@@ -161,8 +163,6 @@ static DECLARE_COMPLETION(xpc_hb_checker
 /* notification that the xpc_discovery thread has exited */
 static DECLARE_COMPLETION(xpc_discovery_exited);
 
-static struct timer_list xpc_hb_timer;
-
 static void xpc_kthread_waitmsgs(struct xpc_partition *, struct xpc_channel *);
 
 static int xpc_system_reboot(struct notifier_block *, unsigned long, void *);
@@ -176,12 +176,54 @@ static struct notifier_block xpc_die_not
 };
 
 enum xp_retval (*xpc_rsvd_page_init) (struct xpc_rsvd_page *rp);
+void (*xpc_heartbeat_init) (void);
+void (*xpc_heartbeat_exit) (void);
+void (*xpc_increment_heartbeat) (void);
+void (*xpc_offline_heartbeat) (void);
+void (*xpc_online_heartbeat) (void);
+void (*xpc_check_remote_hb) (void);
+
 enum xp_retval (*xpc_make_first_contact) (struct xpc_partition *part);
 u64 (*xpc_get_IPI_flags) (struct xpc_partition *part);
 struct xpc_msg *(*xpc_get_deliverable_msg) (struct xpc_channel *ch);
+
+void (*xpc_initiate_partition_activation) (struct xpc_rsvd_page *remote_rp,
+					   u64 remote_rp_pa, int nasid);
+
+void (*xpc_process_act_IRQ_rcvd) (int n_IRQs_expected);
 enum xp_retval (*xpc_setup_infrastructure) (struct xpc_partition *part);
 void (*xpc_teardown_infrastructure) (struct xpc_partition *part);
 
+void (*xpc_mark_partition_engaged) (struct xpc_partition *part);
+void (*xpc_mark_partition_disengaged) (struct xpc_partition *part);
+void (*xpc_request_partition_disengage) (struct xpc_partition *part);
+void (*xpc_cancel_partition_disengage_request) (struct xpc_partition *part);
+u64 (*xpc_partition_engaged) (u64 partid_mask);
+u64 (*xpc_partition_disengage_requested) (u64 partid_mask);
+void (*xpc_clear_partition_engaged) (u64 partid_mask);
+void (*xpc_clear_partition_disengage_request) (u64 partid_mask);
+
+void (*xpc_IPI_send_local_activate) (int from_nasid);
+void (*xpc_IPI_send_activated) (struct xpc_partition *part);
+void (*xpc_IPI_send_local_reactivate) (int from_nasid);
+void (*xpc_IPI_send_disengage) (struct xpc_partition *part);
+
+void (*xpc_IPI_send_closerequest) (struct xpc_channel *ch,
+				   unsigned long *irq_flags);
+void (*xpc_IPI_send_closereply) (struct xpc_channel *ch,
+				 unsigned long *irq_flags);
+void (*xpc_IPI_send_openrequest) (struct xpc_channel *ch,
+				  unsigned long *irq_flags);
+void (*xpc_IPI_send_openreply) (struct xpc_channel *ch,
+				unsigned long *irq_flags);
+
+enum xp_retval (*xpc_allocate_msg) (struct xpc_channel *ch, u32 flags,
+				    struct xpc_msg **address_of_msg);
+
+enum xp_retval (*xpc_send_msg) (struct xpc_channel *ch, struct xpc_msg *msg,
+				u8 notify_type, xpc_notify_func func,
+				void *key);
+void (*xpc_received_msg) (struct xpc_channel *ch, struct xpc_msg *msg);
 
 /*
  * Timer function to enforce the timelimit on the partition disengage request.
@@ -218,7 +260,7 @@ xpc_act_IRQ_handler(int irq, void *dev_i
 static void
 xpc_hb_beater(unsigned long dummy)
 {
-	xpc_vars->heartbeat++;
+	xpc_increment_heartbeat();
 
 	if (time_after_eq(jiffies, xpc_hb_check_timeout))
 		wake_up_interruptible(&xpc_act_IRQ_wq);
@@ -227,6 +269,22 @@ xpc_hb_beater(unsigned long dummy)
 	add_timer(&xpc_hb_timer);
 }
 
+static void
+xpc_start_hb_beater(void)
+{
+	xpc_heartbeat_init();
+	init_timer(&xpc_hb_timer);
+	xpc_hb_timer.function = xpc_hb_beater;
+	xpc_hb_beater(0);
+}
+
+static void
+xpc_stop_hb_beater(void)
+{
+	del_timer_sync(&xpc_hb_timer);
+	xpc_heartbeat_exit();
+}
+
 /*
  * This thread is responsible for nearly all of the partition
  * activation/deactivation.
@@ -244,7 +302,7 @@ xpc_hb_checker(void *ignore)
 
 	/* set our heartbeating to other partitions into motion */
 	xpc_hb_check_timeout = jiffies + (xpc_hb_check_interval * HZ);
-	xpc_hb_beater(0);
+	xpc_start_hb_beater();
 
 	while (!xpc_exiting) {
 
@@ -274,11 +332,8 @@ xpc_hb_checker(void *ignore)
 			dev_dbg(xpc_part, "found an IRQ to process; will be "
 				"resetting xpc_hb_check_timeout\n");
 
-			last_IRQ_count += xpc_identify_act_IRQ_sender();
-			if (last_IRQ_count < new_IRQ_count) {
-				/* retry once to help avoid missing AMO */
-				(void)xpc_identify_act_IRQ_sender();
-			}
+			xpc_process_act_IRQ_rcvd(new_IRQ_count -
+						 last_IRQ_count);
 			last_IRQ_count = new_IRQ_count;
 
 			xpc_hb_check_timeout = jiffies +
@@ -294,6 +349,8 @@ xpc_hb_checker(void *ignore)
 						xpc_exiting));
 	}
 
+	xpc_stop_hb_beater();
+
 	dev_dbg(xpc_part, "heartbeat checker is exiting\n");
 
 	/* mark this thread as having exited */
@@ -401,31 +458,7 @@ xpc_activating(void *__partid)
 
 	dev_dbg(xpc_part, "activating partition %d\n", partid);
 
-	/*
-	 * Register the remote partition's AMOs with SAL so it can handle
-	 * and cleanup errors within that address range should the remote
-	 * partition go down. We don't unregister this range because it is
-	 * difficult to tell when outstanding writes to the remote partition
-	 * are finished and thus when it is safe to unregister. This should
-	 * not result in wasted space in the SAL xp_addr_region table because
-	 * we should get the same page for remote_amos_page_pa after module
-	 * reloads and system reboots.
-	 */
-	if (sn_register_xp_addr_region(part->remote_amos_page_pa,
-				       PAGE_SIZE, 1) < 0) {
-		dev_warn(xpc_part, "xpc_activating(%d) failed to register "
-			 "xp_addr region\n", partid);
-
-		spin_lock_irqsave(&part->act_lock, irq_flags);
-		part->act_state = XPC_P_INACTIVE;
-		XPC_SET_REASON(part, xpPhysAddrRegFailed, __LINE__);
-		spin_unlock_irqrestore(&part->act_lock, irq_flags);
-		part->remote_rp_pa = 0;
-		return 0;
-	}
-
-	xpc_allow_hb(partid, xpc_vars);
-	xpc_IPI_send_activated(part);
+	xpc_allow_hb(partid);
 
 	if (xpc_setup_infrastructure(part) == xpSuccess) {
 		(void)xpc_part_ref(part);	/* this will always succeed */
@@ -440,12 +473,12 @@ xpc_activating(void *__partid)
 		xpc_teardown_infrastructure(part);
 	}
 
-	xpc_disallow_hb(partid, xpc_vars);
+	xpc_disallow_hb(partid);
 	xpc_mark_partition_inactive(part);
 
 	if (part->reason == xpReactivating) {
 		/* interrupting ourselves results in activating partition */
-		xpc_IPI_send_reactivate(part);
+		xpc_IPI_send_local_reactivate(part->reactivate_nasid);
 	}
 
 	return 0;
@@ -478,6 +511,32 @@ xpc_activate_partition(struct xpc_partit
 }
 
 /*
+ * Check to see if there is any channel activity to/from the specified
+ * partition.
+ */
+static void
+xpc_check_for_channel_activity(struct xpc_partition *part)
+{
+	u64 IPI_amo;
+	unsigned long irq_flags;
+
+/* this needs to be uncommented, but I'm thinking this function and the */
+/* ones that call it need to be moved into xpc_sn2.c... */
+	IPI_amo = 0; /* = xpc_IPI_receive(part->local_IPI_amo_va); */
+	if (IPI_amo == 0)
+		return;
+
+	spin_lock_irqsave(&part->IPI_lock, irq_flags);
+	part->local_IPI_amo |= IPI_amo;
+	spin_unlock_irqrestore(&part->IPI_lock, irq_flags);
+
+	dev_dbg(xpc_chan, "received IPI from partid=%d, IPI_amo=0x%lx\n",
+		XPC_PARTID(part), IPI_amo);
+
+	xpc_wakeup_channel_mgr(part);
+}
+
+/*
  * Handle the receipt of a SGI_XPC_NOTIFY IRQ by seeing whether the specified
  * partition actually sent it. Since SGI_XPC_NOTIFY IRQs may be shared by more
  * than one partition, we use an AMO_t structure per partition to indicate
@@ -902,14 +961,11 @@ xpc_do_exit(enum xp_retval reason)
 	} while (1);
 
 	DBUG_ON(xpc_partition_engaged(-1UL));
+	DBUG_ON(xpc_any_hbs_allowed() != 0);
 
 	/* indicate to others that our reserved page is uninitialized */
 	xpc_rsvd_page->stamp = ZERO_STAMP;
 
-	/* now it's time to eliminate our heartbeat */
-	del_timer_sync(&xpc_hb_timer);
-	DBUG_ON(xpc_vars->heartbeating_to_mask != 0);
-
 	if (reason == xpUnloading) {
 		(void)unregister_die_notifier(&xpc_die_notifier);
 		(void)unregister_reboot_notifier(&xpc_reboot_notifier);
@@ -968,7 +1024,7 @@ xpc_die_disengage(void)
 	/* keep xpc_hb_checker thread from doing anything (just in case) */
 	xpc_exiting = 1;
 
-	xpc_vars->heartbeating_to_mask = 0;	/* indicate we're deactivated */
+	xpc_disallow_all_hbs();	/*indicate we're deactivated */
 
 	for (partid = 0; partid < xp_max_npartitions; partid++) {
 		part = &xpc_partitions[partid];
@@ -1054,8 +1110,7 @@ xpc_system_die(struct notifier_block *nb
 		/* fall through */
 	case DIE_MCA_MONARCH_ENTER:
 	case DIE_INIT_MONARCH_ENTER:
-		xpc_vars->heartbeat++;
-		xpc_vars->heartbeat_offline = 1;
+		xpc_offline_heartbeat();
 		break;
 
 	case DIE_KDEBUG_LEAVE:
@@ -1066,8 +1121,7 @@ xpc_system_die(struct notifier_block *nb
 		/* fall through */
 	case DIE_MCA_MONARCH_LEAVE:
 	case DIE_INIT_MONARCH_LEAVE:
-		xpc_vars->heartbeat++;
-		xpc_vars->heartbeat_offline = 0;
+		xpc_online_heartbeat();
 		break;
 	}
 
@@ -1202,9 +1256,6 @@ xpc_init(void)
 	if (ret != 0)
 		dev_warn(xpc_part, "can't register die notifier\n");
 
-	init_timer(&xpc_hb_timer);
-	xpc_hb_timer.function = xpc_hb_beater;
-
 	/*
 	 * The real work-horse behind xpc.  This processes incoming
 	 * interrupts and monitors remote heartbeats.
@@ -1246,7 +1297,6 @@ out_4:
 	/* indicate to others that our reserved page is uninitialized */
 	xpc_rsvd_page->stamp = ZERO_STAMP;
 
-	del_timer_sync(&xpc_hb_timer);
 	(void)unregister_die_notifier(&xpc_die_notifier);
 	(void)unregister_reboot_notifier(&xpc_reboot_notifier);
 out_3:
Index: linux-2.6/drivers/misc/sgi-xp/xpc_uv.c
===================================================================
--- linux-2.6.orig/drivers/misc/sgi-xp/xpc_uv.c	2008-05-28 07:03:09.444499121 -0500
+++ linux-2.6/drivers/misc/sgi-xp/xpc_uv.c	2008-05-28 07:03:15.353233496 -0500
@@ -19,15 +19,22 @@
 /* >>> uv_gpa() is defined in <gru/grukservices.h> */
 #define uv_gpa(_a)		((unsigned long)_a)
 
-/* >>> temporarily define next three items for xpc.h */
-#define	SGI_XPC_ACTIVATE	23
-#define	SGI_XPC_NOTIFY		24
-#define sn_send_IPI_phys(_a, _b, _c, _d)
-
 #include "xpc.h"
 
+static DECLARE_BITMAP(xpc_heartbeating_to_mask_uv, XP_MAX_NPARTITIONS_UV);
+
 static void *xpc_activate_mq;
 
+static void
+xpc_IPI_send_local_activate_uv(struct xpc_partition *part)
+{
+	/*
+	 * >>> make our side think that the remote parition sent an activate
+	 * >>> message our way. Also do what the activate IRQ handler would
+	 * >>> do had one really been sent.
+	 */
+}
+
 static enum xp_retval
 xpc_rsvd_page_init_uv(struct xpc_rsvd_page *rp)
 {
@@ -36,6 +43,41 @@ xpc_rsvd_page_init_uv(struct xpc_rsvd_pa
 	return xpSuccess;
 }
 
+static void
+xpc_increment_heartbeat_uv(void)
+{
+	/* >>> send heartbeat msg to xpc_heartbeating_to_mask partids */
+}
+
+static void
+xpc_heartbeat_init_uv(void)
+{
+	bitmap_zero(xpc_heartbeating_to_mask_uv, XP_MAX_NPARTITIONS_UV);
+	xpc_heartbeating_to_mask = &xpc_heartbeating_to_mask_uv[0];
+}
+
+static void
+xpc_heartbeat_exit_uv(void)
+{
+	/* >>> send heartbeat_offline msg to xpc_heartbeating_to_mask partids */
+}
+
+static void
+xpc_initiate_partition_activation_uv(struct xpc_rsvd_page *remote_rp,
+				     u64 remote_rp_pa, int nasid)
+{
+	short partid = remote_rp->SAL_partid;
+	struct xpc_partition *part = &xpc_partitions[partid];
+
+/*
+ * >>> setup part structure with the bits of info we can glean from the rp
+ * >>>	part->remote_rp_pa = remote_rp_pa;
+ * >>>	part->sn.uv.activate_mq_gpa = remote_rp->sn.activate_mq_gpa;
+ */
+
+	xpc_IPI_send_local_activate_uv(part);
+}
+
 /*
  * Setup the infrastructure necessary to support XPartition Communication
  * between the specified remote partition and the local one.
@@ -83,6 +125,11 @@ void
 xpc_init_uv(void)
 {
 	xpc_rsvd_page_init = xpc_rsvd_page_init_uv;
+	xpc_increment_heartbeat = xpc_increment_heartbeat_uv;
+	xpc_heartbeat_init = xpc_heartbeat_init_uv;
+	xpc_heartbeat_exit = xpc_heartbeat_exit_uv;
+	xpc_initiate_partition_activation =
+	    xpc_initiate_partition_activation_uv;
 	xpc_setup_infrastructure = xpc_setup_infrastructure_uv;
 	xpc_teardown_infrastructure = xpc_teardown_infrastructure_uv;
 	xpc_make_first_contact = xpc_make_first_contact_uv;
Index: linux-2.6/drivers/misc/sgi-xp/xpc_channel.c
===================================================================
--- linux-2.6.orig/drivers/misc/sgi-xp/xpc_channel.c	2008-05-28 07:03:09.384491663 -0500
+++ linux-2.6/drivers/misc/sgi-xp/xpc_channel.c	2008-05-28 07:03:15.369235484 -0500
@@ -1165,7 +1165,7 @@ xpc_disconnect_callout(struct xpc_channe
  * Wait for a message entry to become available for the specified channel,
  * but don't wait any longer than 1 jiffy.
  */
-static enum xp_retval
+enum xp_retval
 xpc_allocate_msg_wait(struct xpc_channel *ch)
 {
 	enum xp_retval ret;
@@ -1193,96 +1193,6 @@ xpc_allocate_msg_wait(struct xpc_channel
 
 /*
  * Allocate an entry for a message from the message queue associated with the
- * specified channel.
- */
-static enum xp_retval
-xpc_allocate_msg(struct xpc_channel *ch, u32 flags,
-		 struct xpc_msg **address_of_msg)
-{
-	struct xpc_msg *msg;
-	enum xp_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 xpNotConnected;
-	}
-
-	/*
-	 * 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 = xpTimeout;
-
-	while (1) {
-
-		put = ch->w_local_GP.put;
-		rmb();	/* guarantee that .put loads before .get */
-		if (put - 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 == xpTimeout)
-			xpc_IPI_send_local_msgrequest(ch);
-
-		if (flags & XPC_NOWAIT) {
-			xpc_msgqueue_deref(ch);
-			return xpNoWait;
-		}
-
-		ret = xpc_allocate_msg_wait(ch);
-		if (ret != xpInterrupted && ret != xpTimeout) {
-			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 xpSuccess;
-}
-
-/*
- * 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.
  *
@@ -1318,144 +1228,6 @@ xpc_initiate_allocate(short partid, int 
 }
 
 /*
- * 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 == 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(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 xp_retval
-xpc_send_msg(struct xpc_channel *ch, struct xpc_msg *msg, u8 notify_type,
-	     xpc_notify_func func, void *key)
-{
-	enum xp_retval ret = xpSuccess;
-	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(&notify->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.
  *
@@ -1586,66 +1358,6 @@ xpc_deliver_msg(struct xpc_channel *ch)
 }
 
 /*
- * 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 == 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(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
@@ -1668,35 +1380,12 @@ xpc_initiate_received(short partid, int 
 	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_npartitions);
 	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);
+	xpc_received_msg(ch, msg);
 
 	/* the call to xpc_msgqueue_ref() was done by xpc_deliver_msg()  */
 	xpc_msgqueue_deref(ch);
--
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