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>

1 files changed, 69 insertions, 19 deletions

diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index e5dc8c44c6fb..9c0c29a2ac86 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);
 }