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>

5 files changed, 97 insertions, 102 deletions

diff --git a/drivers/misc/sgi-xp/xp.h b/drivers/misc/sgi-xp/xp.h
index 43bf2470850..955b5b91323 100644
--- a/drivers/misc/sgi-xp/xp.h
+++ b/drivers/misc/sgi-xp/xp.h
@@ -61,16 +61,6 @@
 #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
  * `users' can communicate with their counterparts on the other partitions.
diff --git a/drivers/misc/sgi-xp/xpc.h b/drivers/misc/sgi-xp/xpc.h
index defd0888118..2111723553b 100644
--- a/drivers/misc/sgi-xp/xpc.h
+++ b/drivers/misc/sgi-xp/xpc.h
@@ -151,26 +151,6 @@ 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.
  *
  * An array of these structures, one per partition, will be defined. As a
@@ -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);
diff --git a/drivers/misc/sgi-xp/xpc_main.c b/drivers/misc/sgi-xp/xpc_main.c
index b5f3c5e59db..36dfccea524 100644
--- a/drivers/misc/sgi-xp/xpc_main.c
+++ b/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();
diff --git a/drivers/misc/sgi-xp/xpc_partition.c b/drivers/misc/sgi-xp/xpc_partition.c
index c769ab8f74e..9f104450478 100644
--- a/drivers/misc/sgi-xp/xpc_partition.c
+++ b/drivers/misc/sgi-xp/xpc_partition.c
@@ -34,21 +34,12 @@ 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.
  */
 void *
@@ -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);
 }
diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index e5dc8c44c6f..9c0c29a2ac8 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/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);
 }