sgi-xp: isolate remote copy buffer to sn2 only

Make the remote copy buffer an sn2 only item.

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

drivers/misc/sgi-xp/xp.h

@@ -60,16 +60,6 @@
 #define XP_MAX_NPARTITIONS_SN2	64
 #define XP_MAX_NPARTITIONS_UV	256
 
-/*
- * Define the number of u64s required to represent all the C-brick nasids
- * as a bitmap.  The cross-partition kernel modules deal only with
- * C-brick nasids, thus the need for bitmaps which don't account for
- * odd-numbered (non C-brick) nasids.
- */
-#define XP_MAX_PHYSNODE_ID	(MAX_NUMALINK_NODES / 2)
-#define XP_NASID_MASK_BYTES	((XP_MAX_PHYSNODE_ID + 7) / 8)
-#define XP_NASID_MASK_WORDS	((XP_MAX_PHYSNODE_ID + 63) / 64)
-
 /*
  * XPC establishes channel connections between the local partition and any
  * other partition that is currently up. Over these channels, kernel-level

drivers/misc/sgi-xp/xpc.h

@@ -150,26 +150,6 @@ struct xpc_vars_sn2 {
 
 #define XPC_V_VERSION _XPC_VERSION(3, 1)    /* version 3.1 of the cross vars */
 
-/*
- * 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, 1 amo variable to identify which remote
- * partitions (i.e., XPCs) consider themselves currently engaged with the
- * local XPC and 1 amo variable to request partition deactivation.
- */
-#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_DEACTIVATE_REQUEST_AMO  (XPC_ENGAGED_PARTITIONS_AMO + 1)
-
 /*
  * The following structure describes the per partition specific variables.
  *
@@ -214,9 +194,10 @@ struct xpc_vars_part_sn2 {
 #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_sn2 *)(XPC_RP_MACH_NASIDS(_rp) + \
-				    xp_nasid_mask_words))
+#define XPC_RP_MACH_NASIDS(_rp) (XPC_RP_PART_NASIDS(_rp) + xpc_nasid_mask_words)
+#define XPC_RP_VARS(_rp)	((struct xpc_vars_sn2 *) \
+				 (XPC_RP_MACH_NASIDS(_rp) + \
+				  xpc_nasid_mask_words))
 
 /*
  * Functions registered by add_timer() or called by kernel_thread() only
@@ -225,11 +206,11 @@ struct xpc_vars_part_sn2 {
  * the passed argument.
  */
 #define XPC_PACK_ARGS(_arg1, _arg2) \
-			((((u64) _arg1) & 0xffffffff) | \
-			((((u64) _arg2) & 0xffffffff) << 32))
+			((((u64)_arg1) & 0xffffffff) | \
+			((((u64)_arg2) & 0xffffffff) << 32))
 
-#define XPC_UNPACK_ARG1(_args)	(((u64) _args) & 0xffffffff)
-#define XPC_UNPACK_ARG2(_args)	((((u64) _args) >> 32) & 0xffffffff)
+#define XPC_UNPACK_ARG1(_args)	(((u64)_args) & 0xffffffff)
+#define XPC_UNPACK_ARG2(_args)	((((u64)_args) >> 32) & 0xffffffff)
 
 /*
  * Define a Get/Put value pair (pointers) used with a message queue.
@@ -710,12 +691,10 @@ extern void xpc_exit_uv(void);
 
 /* found in xpc_partition.c */
 extern int xpc_exiting;
-extern int xp_nasid_mask_words;
+extern int xpc_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;
 extern void *xpc_kmalloc_cacheline_aligned(size_t, gfp_t, void **);
 extern struct xpc_rsvd_page *xpc_setup_rsvd_page(void);
 extern int xpc_identify_activate_IRQ_sender(void);

drivers/misc/sgi-xp/xpc_main.c

@@ -877,7 +877,6 @@ xpc_do_exit(enum xp_retval reason)
 		unregister_sysctl_table(xpc_sysctl);
 
 	kfree(xpc_partitions);
-	kfree(xpc_remote_copy_buffer_base);
 
 	if (is_shub())
 		xpc_exit_sn2();
@@ -1031,7 +1030,9 @@ xpc_init(void)
 	short partid;
 	struct xpc_partition *part;
 	struct task_struct *kthread;
-	size_t buf_size;
+
+	snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
+	snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
 
 	if (is_shub()) {
 		/*
@@ -1054,26 +1055,12 @@ xpc_init(void)
 		return -ENODEV;
 	}
 
-	snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
-	snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
-
-	buf_size = max(XPC_RP_VARS_SIZE,
-		       XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES);
-	xpc_remote_copy_buffer = xpc_kmalloc_cacheline_aligned(buf_size,
-							       GFP_KERNEL,
-						  &xpc_remote_copy_buffer_base);
-	if (xpc_remote_copy_buffer == NULL) {
-		dev_err(xpc_part, "can't get memory for remote copy buffer\n");
-		ret = -ENOMEM;
-		goto out_1;
-	}
-
 	xpc_partitions = kzalloc(sizeof(struct xpc_partition) *
 				 xp_max_npartitions, GFP_KERNEL);
 	if (xpc_partitions == NULL) {
 		dev_err(xpc_part, "can't get memory for partition structure\n");
 		ret = -ENOMEM;
-		goto out_2;
+		goto out_1;
 	}
 
 	/*
@@ -1115,7 +1102,7 @@ xpc_init(void)
 	if (xpc_rsvd_page == NULL) {
 		dev_err(xpc_part, "can't setup our reserved page\n");
 		ret = -EBUSY;
-		goto out_3;
+		goto out_2;
 	}
 
 	/* add ourselves to the reboot_notifier_list */
@@ -1136,7 +1123,7 @@ xpc_init(void)
 	if (IS_ERR(kthread)) {
 		dev_err(xpc_part, "failed while forking hb check thread\n");
 		ret = -EBUSY;
-		goto out_4;
+		goto out_3;
 	}
 
 	/*
@@ -1164,18 +1151,16 @@ xpc_init(void)
 	return 0;
 
 	/* initialization was not successful */
-out_4:
+out_3:
 	/* indicate to others that our reserved page is uninitialized */
 	xpc_rsvd_page->stamp = 0;
 
 	(void)unregister_die_notifier(&xpc_die_notifier);
 	(void)unregister_reboot_notifier(&xpc_reboot_notifier);
-out_3:
+out_2:
 	if (xpc_sysctl)
 		unregister_sysctl_table(xpc_sysctl);
 	kfree(xpc_partitions);
-out_2:
-	kfree(xpc_remote_copy_buffer_base);
 out_1:
 	if (is_shub())
 		xpc_exit_sn2();

drivers/misc/sgi-xp/xpc_partition.c

@@ -34,20 +34,11 @@ struct xpc_rsvd_page *xpc_rsvd_page;
 static u64 *xpc_part_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 */
-int xp_nasid_mask_words;	/* actual size in words of nasid mask */
+static int xpc_sizeof_nasid_mask;	/* actual size in bytes of nasid mask */
+int xpc_nasid_mask_words;	/* actual size in words of nasid mask */
 
 struct xpc_partition *xpc_partitions;
 
-/*
- * Generic buffer used to store a local copy of portions of a remote
- * partition's reserved page (either its header and part_nasids mask,
- * or its vars).
- */
-char *xpc_remote_copy_buffer;
-void *xpc_remote_copy_buffer_base;
-
 /*
  * Guarantee that the kmalloc'd memory is cacheline aligned.
  */
@@ -176,9 +167,9 @@ xpc_setup_rsvd_page(void)
 		/* SAL_version 1 didn't set the nasids_size field */
 		rp->SAL_nasids_size = 128;
 	}
-	xp_sizeof_nasid_mask = rp->SAL_nasids_size;
-	xp_nasid_mask_words = DIV_ROUND_UP(xp_sizeof_nasid_mask,
-					   BYTES_PER_WORD);
+	xpc_sizeof_nasid_mask = rp->SAL_nasids_size;
+	xpc_nasid_mask_words = DIV_ROUND_UP(xpc_sizeof_nasid_mask,
+					    BYTES_PER_WORD);
 
 	/* setup the pointers to the various items in the reserved page */
 	xpc_part_nasids = XPC_RP_PART_NASIDS(rp);
@@ -222,14 +213,14 @@ xpc_get_remote_rp(int nasid, u64 *discovered_nasids,
 
 	/* pull over the reserved page header and part_nasids mask */
 	ret = xp_remote_memcpy(remote_rp, (void *)*remote_rp_pa,
-			       XPC_RP_HEADER_SIZE + xp_sizeof_nasid_mask);
+			       XPC_RP_HEADER_SIZE + xpc_sizeof_nasid_mask);
 	if (ret != xpSuccess)
 		return ret;
 
 	if (discovered_nasids != NULL) {
 		u64 *remote_part_nasids = XPC_RP_PART_NASIDS(remote_rp);
 
-		for (i = 0; i < xp_nasid_mask_words; i++)
+		for (i = 0; i < xpc_nasid_mask_words; i++)
 			discovered_nasids[i] |= remote_part_nasids[i];
 	}
 
@@ -414,12 +405,12 @@ xpc_discovery(void)
 	enum xp_retval ret;
 
 	remote_rp = xpc_kmalloc_cacheline_aligned(XPC_RP_HEADER_SIZE +
-						  xp_sizeof_nasid_mask,
+						  xpc_sizeof_nasid_mask,
 						  GFP_KERNEL, &remote_rp_base);
 	if (remote_rp == NULL)
 		return;
 
-	discovered_nasids = kzalloc(sizeof(u64) * xp_nasid_mask_words,
+	discovered_nasids = kzalloc(sizeof(u64) * xpc_nasid_mask_words,
 				    GFP_KERNEL);
 	if (discovered_nasids == NULL) {
 		kfree(remote_rp_base);
@@ -521,10 +512,10 @@ xpc_initiate_partid_to_nasids(short partid, void *nasid_mask)
 	if (part->remote_rp_pa == 0)
 		return xpPartitionDown;
 
-	memset(nasid_mask, 0, XP_NASID_MASK_BYTES);
+	memset(nasid_mask, 0, xpc_sizeof_nasid_mask);
 
 	part_nasid_pa = (u64)XPC_RP_PART_NASIDS(part->remote_rp_pa);
 
 	return xp_remote_memcpy(nasid_mask, (void *)part_nasid_pa,
-				xp_sizeof_nasid_mask);
+				xpc_sizeof_nasid_mask);
 }

drivers/misc/sgi-xp/xpc_sn2.c

@@ -19,6 +19,43 @@
 #include <asm/sn/sn_sal.h>
 #include "xpc.h"
 
+/*
+ * Define the number of u64s required to represent all the C-brick nasids
+ * as a bitmap.  The cross-partition kernel modules deal only with
+ * C-brick nasids, thus the need for bitmaps which don't account for
+ * odd-numbered (non C-brick) nasids.
+ */
+#define XPC_MAX_PHYSNODES_SN2	(MAX_NUMALINK_NODES / 2)
+#define XP_NASID_MASK_BYTES_SN2	((XPC_MAX_PHYSNODES_SN2 + 7) / 8)
+#define XP_NASID_MASK_WORDS_SN2	((XPC_MAX_PHYSNODES_SN2 + 63) / 64)
+
+/*
+ * 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_SN2) to identify
+ * the senders of ACTIVATE IRQs, 1 amo variable to identify which remote
+ * partitions (i.e., XPCs) consider themselves currently engaged with the
+ * local XPC and 1 amo variable to request partition deactivation.
+ */
+#define XPC_NOTIFY_IRQ_AMOS_SN2		0
+#define XPC_ACTIVATE_IRQ_AMOS_SN2	(XPC_NOTIFY_IRQ_AMOS_SN2 + \
+					 XP_MAX_NPARTITIONS_SN2)
+#define XPC_ENGAGED_PARTITIONS_AMO_SN2	(XPC_ACTIVATE_IRQ_AMOS_SN2 + \
+					 XP_NASID_MASK_WORDS_SN2)
+#define XPC_DEACTIVATE_REQUEST_AMO_SN2	(XPC_ENGAGED_PARTITIONS_AMO_SN2 + 1)
+
+/*
+ * Buffer used to store a local copy of portions of a remote partition's
+ * reserved page (either its header and part_nasids mask, or its vars).
+ */
+static char *xpc_remote_copy_buffer_sn2;
+static void *xpc_remote_copy_buffer_base_sn2;
+
 static struct xpc_vars_sn2 *xpc_vars;	/* >>> Add _sn2 suffix? */
 static struct xpc_vars_part_sn2 *xpc_vars_part; /* >>> Add _sn2 suffix? */
 
@@ -176,7 +213,7 @@ xpc_send_activate_IRQ_sn2(u64 amos_page_pa, int from_nasid, int to_nasid,
 	int w_index = XPC_NASID_W_INDEX(from_nasid);
 	int b_index = XPC_NASID_B_INDEX(from_nasid);
 	struct amo *amos = (struct amo *)__va(amos_page_pa +
-					      (XPC_ACTIVATE_IRQ_AMOS *
+					      (XPC_ACTIVATE_IRQ_AMOS_SN2 *
 					      sizeof(struct amo)));
 
 	(void)xpc_send_IRQ_sn2(&amos[w_index], (1UL << b_index), to_nasid,
@@ -189,7 +226,7 @@ xpc_send_local_activate_IRQ_sn2(int from_nasid)
 	int w_index = XPC_NASID_W_INDEX(from_nasid);
 	int b_index = XPC_NASID_B_INDEX(from_nasid);
 	struct amo *amos = (struct amo *)__va(xpc_vars->amos_page_pa +
-					      (XPC_ACTIVATE_IRQ_AMOS *
+					      (XPC_ACTIVATE_IRQ_AMOS_SN2 *
 					      sizeof(struct amo)));
 
 	/* fake the sending and receipt of an activate IRQ from remote nasid */
@@ -395,7 +432,7 @@ xpc_indicate_partition_engaged_sn2(struct xpc_partition *part)
 {
 	unsigned long irq_flags;
 	struct amo *amo = (struct amo *)__va(part->sn.sn2.remote_amos_page_pa +
-					     (XPC_ENGAGED_PARTITIONS_AMO *
+					     (XPC_ENGAGED_PARTITIONS_AMO_SN2 *
 					     sizeof(struct amo)));
 
 	local_irq_save(irq_flags);
@@ -422,7 +459,7 @@ xpc_indicate_partition_disengaged_sn2(struct xpc_partition *part)
 	struct xpc_partition_sn2 *part_sn2 = &part->sn.sn2;
 	unsigned long irq_flags;
 	struct amo *amo = (struct amo *)__va(part_sn2->remote_amos_page_pa +
-					     (XPC_ENGAGED_PARTITIONS_AMO *
+					     (XPC_ENGAGED_PARTITIONS_AMO_SN2 *
 					     sizeof(struct amo)));
 
 	local_irq_save(irq_flags);
@@ -455,7 +492,7 @@ xpc_indicate_partition_disengaged_sn2(struct xpc_partition *part)
 static int
 xpc_partition_engaged_sn2(short partid)
 {
-	struct amo *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
+	struct amo *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO_SN2;
 
 	/* our partition's amo variable ANDed with partid mask */
 	return (FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) &
@@ -465,7 +502,7 @@ xpc_partition_engaged_sn2(short partid)
 static int
 xpc_any_partition_engaged_sn2(void)
 {
-	struct amo *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
+	struct amo *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO_SN2;
 
 	/* our partition's amo variable */
 	return FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) != 0;
@@ -474,7 +511,7 @@ xpc_any_partition_engaged_sn2(void)
 static void
 xpc_assume_partition_disengaged_sn2(short partid)
 {
-	struct amo *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO;
+	struct amo *amo = xpc_vars->amos_page + XPC_ENGAGED_PARTITIONS_AMO_SN2;
 
 	/* clear bit(s) based on partid mask in our partition's amo */
 	FETCHOP_STORE_OP(TO_AMO((u64)&amo->variable), FETCHOP_AND,
@@ -599,12 +636,12 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
 	       xp_max_npartitions);
 
 	/* initialize the activate IRQ related amo variables */
-	for (i = 0; i < xp_nasid_mask_words; i++)
-		(void)xpc_init_IRQ_amo_sn2(XPC_ACTIVATE_IRQ_AMOS + i);
+	for (i = 0; i < xpc_nasid_mask_words; i++)
+		(void)xpc_init_IRQ_amo_sn2(XPC_ACTIVATE_IRQ_AMOS_SN2 + i);
 
 	/* initialize the engaged remote partitions related amo variables */
-	(void)xpc_init_IRQ_amo_sn2(XPC_ENGAGED_PARTITIONS_AMO);
-	(void)xpc_init_IRQ_amo_sn2(XPC_DEACTIVATE_REQUEST_AMO);
+	(void)xpc_init_IRQ_amo_sn2(XPC_ENGAGED_PARTITIONS_AMO_SN2);
+	(void)xpc_init_IRQ_amo_sn2(XPC_DEACTIVATE_REQUEST_AMO_SN2);
 
 	return xpSuccess;
 }
@@ -657,7 +694,7 @@ xpc_check_remote_hb_sn2(void)
 	short partid;
 	enum xp_retval ret;
 
-	remote_vars = (struct xpc_vars_sn2 *)xpc_remote_copy_buffer;
+	remote_vars = (struct xpc_vars_sn2 *)xpc_remote_copy_buffer_sn2;
 
 	for (partid = 0; partid < xp_max_npartitions; partid++) {
 
@@ -749,7 +786,7 @@ xpc_request_partition_deactivation_sn2(struct xpc_partition *part)
 	struct xpc_partition_sn2 *part_sn2 = &part->sn.sn2;
 	unsigned long irq_flags;
 	struct amo *amo = (struct amo *)__va(part_sn2->remote_amos_page_pa +
-					     (XPC_DEACTIVATE_REQUEST_AMO *
+					     (XPC_DEACTIVATE_REQUEST_AMO_SN2 *
 					     sizeof(struct amo)));
 
 	local_irq_save(irq_flags);
@@ -784,7 +821,7 @@ xpc_cancel_partition_deactivation_request_sn2(struct xpc_partition *part)
 {
 	unsigned long irq_flags;
 	struct amo *amo = (struct amo *)__va(part->sn.sn2.remote_amos_page_pa +
-					     (XPC_DEACTIVATE_REQUEST_AMO *
+					     (XPC_DEACTIVATE_REQUEST_AMO_SN2 *
 					     sizeof(struct amo)));
 
 	local_irq_save(irq_flags);
@@ -808,7 +845,7 @@ xpc_cancel_partition_deactivation_request_sn2(struct xpc_partition *part)
 static int
 xpc_partition_deactivation_requested_sn2(short partid)
 {
-	struct amo *amo = xpc_vars->amos_page + XPC_DEACTIVATE_REQUEST_AMO;
+	struct amo *amo = xpc_vars->amos_page + XPC_DEACTIVATE_REQUEST_AMO_SN2;
 
 	/* our partition's amo variable ANDed with partid mask */
 	return (FETCHOP_LOAD_OP(TO_AMO((u64)&amo->variable), FETCHOP_LOAD) &
@@ -898,7 +935,7 @@ xpc_identify_activate_IRQ_req_sn2(int nasid)
 
 	/* pull over the reserved page structure */
 
-	remote_rp = (struct xpc_rsvd_page *)xpc_remote_copy_buffer;
+	remote_rp = (struct xpc_rsvd_page *)xpc_remote_copy_buffer_sn2;
 
 	ret = xpc_get_remote_rp(nasid, NULL, remote_rp, &remote_rp_pa);
 	if (ret != xpSuccess) {
@@ -917,7 +954,7 @@ xpc_identify_activate_IRQ_req_sn2(int nasid)
 
 	/* pull over the cross partition variables */
 
-	remote_vars = (struct xpc_vars_sn2 *)xpc_remote_copy_buffer;
+	remote_vars = (struct xpc_vars_sn2 *)xpc_remote_copy_buffer_sn2;
 
 	ret = xpc_get_remote_vars_sn2(remote_vars_pa, remote_vars);
 	if (ret != xpSuccess) {
@@ -996,10 +1033,10 @@ xpc_identify_activate_IRQ_sender_sn2(void)
 	int n_IRQs_detected = 0;
 	struct amo *act_amos;
 
-	act_amos = xpc_vars->amos_page + XPC_ACTIVATE_IRQ_AMOS;
+	act_amos = xpc_vars->amos_page + XPC_ACTIVATE_IRQ_AMOS_SN2;
 
 	/* scan through act amo variable looking for non-zero entries */
-	for (word = 0; word < xp_nasid_mask_words; word++) {
+	for (word = 0; word < xpc_nasid_mask_words; word++) {
 
 		if (xpc_exiting)
 			break;
@@ -2334,6 +2371,7 @@ int
 xpc_init_sn2(void)
 {
 	int ret;
+	size_t buf_size;
 
 	xpc_rsvd_page_init = xpc_rsvd_page_init_sn2;
 	xpc_increment_heartbeat = xpc_increment_heartbeat_sn2;
@@ -2378,6 +2416,16 @@ xpc_init_sn2(void)
 	xpc_send_msg = xpc_send_msg_sn2;
 	xpc_received_msg = xpc_received_msg_sn2;
 
+	buf_size = max(XPC_RP_VARS_SIZE,
+		       XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES_SN2);
+	xpc_remote_copy_buffer_sn2 = xpc_kmalloc_cacheline_aligned(buf_size,
+								   GFP_KERNEL,
+					      &xpc_remote_copy_buffer_base_sn2);
+	if (xpc_remote_copy_buffer_sn2 == NULL) {
+		dev_err(xpc_part, "can't get memory for remote copy buffer\n");
+		return -ENOMEM;
+	}
+
 	/* open up protections for IPI and [potentially] amo operations */
 	xpc_allow_IPI_ops_sn2();
 	xpc_allow_amo_ops_shub_wars_1_1_sn2();
@@ -2394,6 +2442,7 @@ xpc_init_sn2(void)
 		dev_err(xpc_part, "can't register ACTIVATE IRQ handler, "
 			"errno=%d\n", -ret);
 		xpc_disallow_IPI_ops_sn2();
+		kfree(xpc_remote_copy_buffer_base_sn2);
 	}
 	return ret;
 }
@@ -2403,4 +2452,5 @@ xpc_exit_sn2(void)
 {
 	free_irq(SGI_XPC_ACTIVATE, NULL);
 	xpc_disallow_IPI_ops_sn2();
+	kfree(xpc_remote_copy_buffer_base_sn2);
 }