[IA64] move XP and XPC to drivers/misc/sgi-xp

Move XPC and XPNET from arch/ia64/sn/kernel to drivers/misc/sgi-xp.

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

1 files changed, 1239 insertions, 0 deletions

diff --git a/drivers/misc/sgi-xp/xpc_partition.c b/drivers/misc/sgi-xp/xpc_partition.c
new file mode 100644
index 000000000000..7412dc7351cd
--- /dev/null
+++ b/drivers/misc/sgi-xp/xpc_partition.c
@@ -0,0 +1,1239 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
+ */
+
+
+/*
+ * Cross Partition Communication (XPC) partition support.
+ *
+ *      This is the part of XPC that detects the presence/absence of
+ *      other partitions. It provides a heartbeat and monitors the
+ *      heartbeats of other partitions.
+ *
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/sysctl.h>
+#include <linux/cache.h>
+#include <linux/mmzone.h>
+#include <linux/nodemask.h>
+#include <asm/uncached.h>
+#include <asm/sn/bte.h>
+#include <asm/sn/intr.h>
+#include <asm/sn/sn_sal.h>
+#include <asm/sn/nodepda.h>
+#include <asm/sn/addrs.h>
+#include "xpc.h"
+
+
+/* XPC is exiting flag */
+int xpc_exiting;
+
+
+/* SH_IPI_ACCESS shub register value on startup */
+static u64 xpc_sh1_IPI_access;
+static u64 xpc_sh2_IPI_access0;
+static u64 xpc_sh2_IPI_access1;
+static u64 xpc_sh2_IPI_access2;
+static u64 xpc_sh2_IPI_access3;
+
+
+/* original protection values for each node */
+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;
+struct xpc_vars *xpc_vars;
+struct xpc_vars_part *xpc_vars_part;
+
+static int xp_nasid_mask_bytes; /* actual size in bytes of nasid mask */
+static int xp_nasid_mask_words; /* actual size in words of nasid mask */
+
+
+/*
+ * For performance reasons, each entry of xpc_partitions[] is cacheline
+ * aligned. And xpc_partitions[] is padded with an additional entry at the
+ * end so that the last legitimate entry doesn't share its cacheline with
+ * another variable.
+ */
+struct xpc_partition xpc_partitions[XP_MAX_PARTITIONS + 1];
+
+
+/*
+ * 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 *
+xpc_kmalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
+{
+        /* see if kmalloc will give us cachline aligned memory by default */
+        *base = kmalloc(size, flags);
+        if (*base == NULL) {
+                return NULL;
+        }
+        if ((u64) *base == L1_CACHE_ALIGN((u64) *base)) {
+                return *base;
+        }
+        kfree(*base);
+
+        /* nope, we'll have to do it ourselves */
+        *base = kmalloc(size + L1_CACHE_BYTES, flags);
+        if (*base == NULL) {
+                return NULL;
+        }
+        return (void *) L1_CACHE_ALIGN((u64) *base);
+}
+
+
+/*
+ * Given a nasid, get the physical address of the  partition's reserved page
+ * for that nasid. This function returns 0 on any error.
+ */
+static u64
+xpc_get_rsvd_page_pa(int nasid)
+{
+        bte_result_t bte_res;
+        s64 status;
+        u64 cookie = 0;
+        u64 rp_pa = nasid;      /* seed with nasid */
+        u64 len = 0;
+        u64 buf = buf;
+        u64 buf_len = 0;
+        void *buf_base = NULL;
+
+
+        while (1) {
+
+                status = sn_partition_reserved_page_pa(buf, &cookie, &rp_pa,
+                                                                &len);
+
+                dev_dbg(xpc_part, "SAL returned with status=%li, cookie="
+                        "0x%016lx, address=0x%016lx, len=0x%016lx\n",
+                        status, cookie, rp_pa, len);
+
+                if (status != SALRET_MORE_PASSES) {
+                        break;
+                }
+
+                if (L1_CACHE_ALIGN(len) > buf_len) {
+                        kfree(buf_base);
+                        buf_len = L1_CACHE_ALIGN(len);
+                        buf = (u64) xpc_kmalloc_cacheline_aligned(buf_len,
+                                                        GFP_KERNEL, &buf_base);
+                        if (buf_base == NULL) {
+                                dev_err(xpc_part, "unable to kmalloc "
+                                        "len=0x%016lx\n", buf_len);
+                                status = SALRET_ERROR;
+                                break;
+                        }
+                }
+
+                bte_res = xp_bte_copy(rp_pa, buf, buf_len,
+                                        (BTE_NOTIFY | BTE_WACQUIRE), NULL);
+                if (bte_res != BTE_SUCCESS) {
+                        dev_dbg(xpc_part, "xp_bte_copy failed %i\n", bte_res);
+                        status = SALRET_ERROR;
+                        break;
+                }
+        }
+
+        kfree(buf_base);
+
+        if (status != SALRET_OK) {
+                rp_pa = 0;
+        }
+        dev_dbg(xpc_part, "reserved page at phys address 0x%016lx\n", rp_pa);
+        return rp_pa;
+}
+
+
+/*
+ * Fill the partition reserved page with the information needed by
+ * other partitions to discover we are alive and establish initial
+ * communications.
+ */
+struct xpc_rsvd_page *
+xpc_rsvd_page_init(void)
+{
+        struct xpc_rsvd_page *rp;
+        AMO_t *amos_page;
+        u64 rp_pa, nasid_array = 0;
+        int i, ret;
+
+
+        /* get the local reserved page's address */
+
+        preempt_disable();
+        rp_pa = xpc_get_rsvd_page_pa(cpuid_to_nasid(smp_processor_id()));
+        preempt_enable();
+        if (rp_pa == 0) {
+                dev_err(xpc_part, "SAL failed to locate the reserved page\n");
+                return NULL;
+        }
+        rp = (struct xpc_rsvd_page *) __va(rp_pa);
+
+        if (rp->partid != sn_partition_id) {
+                dev_err(xpc_part, "the reserved page's partid of %d should be "
+                        "%d\n", rp->partid, sn_partition_id);
+                return NULL;
+        }
+
+        rp->version = XPC_RP_VERSION;
+
+        /* establish the actual sizes of the nasid masks */
+        if (rp->SAL_version == 1) {
+                /* SAL_version 1 didn't set the nasids_size field */
+                rp->nasids_size = 128;
+        }
+        xp_nasid_mask_bytes = rp->nasids_size;
+        xp_nasid_mask_words = xp_nasid_mask_bytes / 8;
+
+        /* setup the pointers to the various items in the reserved page */
+        xpc_part_nasids = XPC_RP_PART_NASIDS(rp);
+        xpc_mach_nasids = XPC_RP_MACH_NASIDS(rp);
+        xpc_vars = XPC_RP_VARS(rp);
+        xpc_vars_part = XPC_RP_VARS_PART(rp);
+
+        /*
+         * Before clearing xpc_vars, see if a page of AMOs had been previously
+         * allocated. If not we'll need to allocate one and set permissions
+         * so that cross-partition AMOs are allowed.
+         *
+         * The allocated AMO page needs MCA reporting to remain disabled after
+         * XPC has unloaded.  To make this work, we keep a copy of the pointer
+         * to this page (i.e., amos_page) in the struct xpc_vars structure,
+         * which is pointed to by the reserved page, and re-use that saved copy
+         * on subsequent loads of XPC. This AMO page is never freed, and its
+         * memory protections are never restricted.
+         */
+        if ((amos_page = xpc_vars->amos_page) == NULL) {
+                amos_page = (AMO_t *) TO_AMO(uncached_alloc_page(0));
+                if (amos_page == NULL) {
+                        dev_err(xpc_part, "can't allocate page of AMOs\n");
+                        return NULL;
+                }
+
+                /*
+                 * Open up AMO-R/W to cpu.  This is done for Shub 1.1 systems
+                 * when xpc_allow_IPI_ops() is called via xpc_hb_init().
+                 */
+                if (!enable_shub_wars_1_1()) {
+                        ret = sn_change_memprotect(ia64_tpa((u64) amos_page),
+                                        PAGE_SIZE, SN_MEMPROT_ACCESS_CLASS_1,
+                                        &nasid_array);
+                        if (ret != 0) {
+                                dev_err(xpc_part, "can't change memory "
+                                        "protections\n");
+                                uncached_free_page(__IA64_UNCACHED_OFFSET |
+                                                   TO_PHYS((u64) amos_page));
+                                return NULL;
+                        }
+                }
+        } else if (!IS_AMO_ADDRESS((u64) amos_page)) {
+                /*
+                 * EFI's XPBOOT can also set amos_page in the reserved page,
+                 * but it happens to leave it as an uncached physical address
+                 * and we need it to be an uncached virtual, so we'll have to
+                 * convert it.
+                 */
+                if (!IS_AMO_PHYS_ADDRESS((u64) amos_page)) {
+                        dev_err(xpc_part, "previously used amos_page address "
+                                "is bad = 0x%p\n", (void *) amos_page);
+                        return NULL;
+                }
+                amos_page = (AMO_t *) TO_AMO((u64) amos_page);
+        }
+
+        /* clear xpc_vars */
+        memset(xpc_vars, 0, sizeof(struct xpc_vars));
+
+        xpc_vars->version = XPC_V_VERSION;
+        xpc_vars->act_nasid = cpuid_to_nasid(0);
+        xpc_vars->act_phys_cpuid = cpu_physical_id(0);
+        xpc_vars->vars_part_pa = __pa(xpc_vars_part);
+        xpc_vars->amos_page_pa = ia64_tpa((u64) amos_page);
+        xpc_vars->amos_page = amos_page;  /* save for next load of XPC */
+
+
+        /* clear xpc_vars_part */
+        memset((u64 *) xpc_vars_part, 0, sizeof(struct xpc_vars_part) *
+                                                        XP_MAX_PARTITIONS);
+
+        /* 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);
+        }
+
+        /* initialize the engaged remote partitions related AMO variables */
+        (void) xpc_IPI_init(XPC_ENGAGED_PARTITIONS_AMO);
+        (void) xpc_IPI_init(XPC_DISENGAGE_REQUEST_AMO);
+
+        /* timestamp of when reserved page was setup by XPC */
+        rp->stamp = CURRENT_TIME;
+
+        /*
+         * This signifies to the remote partition that our reserved
+         * page is initialized.
+         */
+        rp->vars_pa = __pa(xpc_vars);
+
+        return rp;
+}
+
+
+/*
+ * Change protections to allow IPI operations (and AMO operations on
+ * Shub 1.1 systems).
+ */
+void
+xpc_allow_IPI_ops(void)
+{
+        int node;
+        int nasid;
+
+
+        // >>> Change SH_IPI_ACCESS code to use SAL call once it is available.
+
+        if (is_shub2()) {
+                xpc_sh2_IPI_access0 =
+                        (u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS0));
+                xpc_sh2_IPI_access1 =
+                        (u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS1));
+                xpc_sh2_IPI_access2 =
+                        (u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS2));
+                xpc_sh2_IPI_access3 =
+                        (u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS3));
+
+                for_each_online_node(node) {
+                        nasid = cnodeid_to_nasid(node);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS0),
+                                                                -1UL);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS1),
+                                                                -1UL);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS2),
+                                                                -1UL);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS3),
+                                                                -1UL);
+                }
+
+        } else {
+                xpc_sh1_IPI_access =
+                        (u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH1_IPI_ACCESS));
+
+                for_each_online_node(node) {
+                        nasid = cnodeid_to_nasid(node);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH1_IPI_ACCESS),
+                                                                -1UL);
+
+                        /*
+                         * Since the BIST collides with memory operations on
+                         * SHUB 1.1 sn_change_memprotect() cannot be used.
+                         */
+                        if (enable_shub_wars_1_1()) {
+                                /* open up everything */
+                                xpc_prot_vec[node] = (u64) HUB_L((u64 *)
+                                                GLOBAL_MMR_ADDR(nasid,
+                                                SH1_MD_DQLP_MMR_DIR_PRIVEC0));
+                                HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
+                                                SH1_MD_DQLP_MMR_DIR_PRIVEC0),
+                                                                -1UL);
+                                HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
+                                                SH1_MD_DQRP_MMR_DIR_PRIVEC0),
+                                                                -1UL);
+                        }
+                }
+        }
+}
+
+
+/*
+ * Restrict protections to disallow IPI operations (and AMO operations on
+ * Shub 1.1 systems).
+ */
+void
+xpc_restrict_IPI_ops(void)
+{
+        int node;
+        int nasid;
+
+
+        // >>> Change SH_IPI_ACCESS code to use SAL call once it is available.
+
+        if (is_shub2()) {
+
+                for_each_online_node(node) {
+                        nasid = cnodeid_to_nasid(node);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS0),
+                                                        xpc_sh2_IPI_access0);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS1),
+                                                        xpc_sh2_IPI_access1);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS2),
+                                                        xpc_sh2_IPI_access2);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS3),
+                                                        xpc_sh2_IPI_access3);
+                }
+
+        } else {
+
+                for_each_online_node(node) {
+                        nasid = cnodeid_to_nasid(node);
+                        HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH1_IPI_ACCESS),
+                                                        xpc_sh1_IPI_access);
+
+                        if (enable_shub_wars_1_1()) {
+                                HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
+                                                SH1_MD_DQLP_MMR_DIR_PRIVEC0),
+                                                        xpc_prot_vec[node]);
+                                HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
+                                                SH1_MD_DQRP_MMR_DIR_PRIVEC0),
+                                                        xpc_prot_vec[node]);
+                        }
+                }
+        }
+}
+
+
+/*
+ * 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;
+        partid_t partid;
+        bte_result_t bres;
+
+
+        remote_vars = (struct xpc_vars *) xpc_remote_copy_buffer;
+
+        for (partid = 1; partid < XP_MAX_PARTITIONS; 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 */
+                bres = xp_bte_copy(part->remote_vars_pa,
+                                        (u64) remote_vars,
+                                        XPC_RP_VARS_SIZE,
+                                        (BTE_NOTIFY | BTE_WACQUIRE), NULL);
+                if (bres != BTE_SUCCESS) {
+                        XPC_DEACTIVATE_PARTITION(part,
+                                                xpc_map_bte_errors(bres));
+                        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, xpcNoHeartbeat);
+                        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 xpc_retval
+xpc_get_remote_rp(int nasid, u64 *discovered_nasids,
+                struct xpc_rsvd_page *remote_rp, u64 *remote_rp_pa)
+{
+        int bres, i;
+
+
+        /* get the reserved page's physical address */
+
+        *remote_rp_pa = xpc_get_rsvd_page_pa(nasid);
+        if (*remote_rp_pa == 0) {
+                return xpcNoRsvdPageAddr;
+        }
+
+
+        /* pull over the reserved page header and part_nasids mask */
+        bres = xp_bte_copy(*remote_rp_pa, (u64) remote_rp,
+                                XPC_RP_HEADER_SIZE + xp_nasid_mask_bytes,
+                                (BTE_NOTIFY | BTE_WACQUIRE), NULL);
+        if (bres != BTE_SUCCESS) {
+                return xpc_map_bte_errors(bres);
+        }
+
+
+        if (discovered_nasids != NULL) {
+                u64 *remote_part_nasids = XPC_RP_PART_NASIDS(remote_rp);
+
+
+                for (i = 0; i < xp_nasid_mask_words; i++) {
+                        discovered_nasids[i] |= remote_part_nasids[i];
+                }
+        }
+
+
+        /* check that the partid is for another partition */
+
+        if (remote_rp->partid < 1 ||
+                                remote_rp->partid > (XP_MAX_PARTITIONS - 1)) {
+                return xpcInvalidPartid;
+        }
+
+        if (remote_rp->partid == sn_partition_id) {
+                return xpcLocalPartid;
+        }
+
+
+        if (XPC_VERSION_MAJOR(remote_rp->version) !=
+                                        XPC_VERSION_MAJOR(XPC_RP_VERSION)) {
+                return xpcBadVersion;
+        }
+
+        return xpcSuccess;
+}
+
+
+/*
+ * 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 xpc_retval
+xpc_get_remote_vars(u64 remote_vars_pa, struct xpc_vars *remote_vars)
+{
+        int bres;
+
+
+        if (remote_vars_pa == 0) {
+                return xpcVarsNotSet;
+        }
+
+        /* pull over the cross partition variables */
+        bres = xp_bte_copy(remote_vars_pa, (u64) remote_vars, XPC_RP_VARS_SIZE,
+                                (BTE_NOTIFY | BTE_WACQUIRE), NULL);
+        if (bres != BTE_SUCCESS) {
+                return xpc_map_bte_errors(bres);
+        }
+
+        if (XPC_VERSION_MAJOR(remote_vars->version) !=
+                                        XPC_VERSION_MAJOR(XPC_V_VERSION)) {
+                return xpcBadVersion;
+        }
+
+        return xpcSuccess;
+}
+
+
+/*
+ * 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);
+
+        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 };
+        partid_t partid;
+        struct xpc_partition *part;
+        enum xpc_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 != xpcSuccess) {
+                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->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->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 != xpcSuccess) {
+
+                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, xpcReactivating);
+                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, xpcReactivating);
+
+        } else if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version) &&
+                        xpc_partition_disengage_requested(1UL << partid)) {
+                XPC_DEACTIVATE_PARTITION(part, xpcOtherGoingDown);
+        }
+}
+
+
+/*
+ * 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.
+ */
+int
+xpc_partition_disengaged(struct xpc_partition *part)
+{
+        partid_t partid = XPC_PARTID(part);
+        int disengaged;
+
+
+        disengaged = (xpc_partition_engaged(1UL << partid) == 0);
+        if (part->disengage_request_timeout) {
+                if (!disengaged) {
+                        if (time_before(jiffies, part->disengage_request_timeout)) {
+                                /* timelimit hasn't been reached yet */
+                                return 0;
+                        }
+
+                        /*
+                         * Other side hasn't responded to our disengage
+                         * request in a timely fashion, so assume it's dead.
+                         */
+
+                        dev_info(xpc_part, "disengage from remote partition %d "
+                                "timed out\n", partid);
+                        xpc_disengage_request_timedout = 1;
+                        xpc_clear_partition_engaged(1UL << partid);
+                        disengaged = 1;
+                }
+                part->disengage_request_timeout = 0;
+
+                /* cancel the timer function, provided it's not us */
+                if (!in_interrupt()) {
+                        del_singleshot_timer_sync(&part->
+                                                      disengage_request_timer);
+                }
+
+                DBUG_ON(part->act_state != XPC_P_DEACTIVATING &&
+                                        part->act_state != XPC_P_INACTIVE);
+                if (part->act_state != XPC_P_INACTIVE) {
+                        xpc_wakeup_channel_mgr(part);
+                }
+
+                if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version)) {
+                        xpc_cancel_partition_disengage_request(part);
+                }
+        }
+        return disengaged;
+}
+
+
+/*
+ * Mark specified partition as active.
+ */
+enum xpc_retval
+xpc_mark_partition_active(struct xpc_partition *part)
+{
+        unsigned long irq_flags;
+        enum xpc_retval ret;
+
+
+        dev_dbg(xpc_part, "setting partition %d to ACTIVE\n", XPC_PARTID(part));
+
+        spin_lock_irqsave(&part->act_lock, irq_flags);
+        if (part->act_state == XPC_P_ACTIVATING) {
+                part->act_state = XPC_P_ACTIVE;
+                ret = xpcSuccess;
+        } else {
+                DBUG_ON(part->reason == xpcSuccess);
+                ret = part->reason;
+        }
+        spin_unlock_irqrestore(&part->act_lock, irq_flags);
+
+        return ret;
+}
+
+
+/*
+ * Notify XPC that the partition is down.
+ */
+void
+xpc_deactivate_partition(const int line, struct xpc_partition *part,
+                                enum xpc_retval reason)
+{
+        unsigned long irq_flags;
+
+
+        spin_lock_irqsave(&part->act_lock, irq_flags);
+
+        if (part->act_state == XPC_P_INACTIVE) {
+                XPC_SET_REASON(part, reason, line);
+                spin_unlock_irqrestore(&part->act_lock, irq_flags);
+                if (reason == xpcReactivating) {
+                        /* we interrupt ourselves to reactivate partition */
+                        xpc_IPI_send_reactivate(part);
+                }
+                return;
+        }
+        if (part->act_state == XPC_P_DEACTIVATING) {
+                if ((part->reason == xpcUnloading && reason != xpcUnloading) ||
+                                        reason == xpcReactivating) {
+                        XPC_SET_REASON(part, reason, line);
+                }
+                spin_unlock_irqrestore(&part->act_lock, irq_flags);
+                return;
+        }
+
+        part->act_state = XPC_P_DEACTIVATING;
+        XPC_SET_REASON(part, reason, line);
+
+        spin_unlock_irqrestore(&part->act_lock, irq_flags);
+
+        if (XPC_SUPPORTS_DISENGAGE_REQUEST(part->remote_vars_version)) {
+                xpc_request_partition_disengage(part);
+                xpc_IPI_send_disengage(part);
+
+                /* set a timelimit on the disengage request */
+                part->disengage_request_timeout = jiffies +
+                                        (xpc_disengage_request_timelimit * HZ);
+                part->disengage_request_timer.expires =
+                                        part->disengage_request_timeout;
+                add_timer(&part->disengage_request_timer);
+        }
+
+        dev_dbg(xpc_part, "bringing partition %d down, reason = %d\n",
+                XPC_PARTID(part), reason);
+
+        xpc_partition_going_down(part, reason);
+}
+
+
+/*
+ * Mark specified partition as inactive.
+ */
+void
+xpc_mark_partition_inactive(struct xpc_partition *part)
+{
+        unsigned long irq_flags;
+
+
+        dev_dbg(xpc_part, "setting partition %d to INACTIVE\n",
+                XPC_PARTID(part));
+
+        spin_lock_irqsave(&part->act_lock, irq_flags);
+        part->act_state = XPC_P_INACTIVE;
+        spin_unlock_irqrestore(&part->act_lock, irq_flags);
+        part->remote_rp_pa = 0;
+}
+
+
+/*
+ * SAL has provided a partition and machine mask.  The partition mask
+ * contains a bit for each even nasid in our partition.  The machine
+ * mask contains a bit for each even nasid in the entire machine.
+ *
+ * Using those two bit arrays, we can determine which nasids are
+ * known in the machine.  Each should also have a reserved page
+ * initialized if they are available for partitioning.
+ */
+void
+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;
+        partid_t partid;
+        struct xpc_partition *part;
+        u64 *discovered_nasids;
+        enum xpc_retval ret;
+
+
+        remote_rp = xpc_kmalloc_cacheline_aligned(XPC_RP_HEADER_SIZE +
+                                                xp_nasid_mask_bytes,
+                                                GFP_KERNEL, &remote_rp_base);
+        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) {
+                kfree(remote_rp_base);
+                return;
+        }
+
+        rp = (struct xpc_rsvd_page *) xpc_rsvd_page;
+
+        /*
+         * The term 'region' in this context refers to the minimum number of
+         * nodes that can comprise an access protection grouping. The access
+         * protection is in regards to memory, IOI and IPI.
+         */
+        max_regions = 64;
+        region_size = sn_region_size;
+
+        switch (region_size) {
+        case 128:
+                max_regions *= 2;
+        case 64:
+                max_regions *= 2;
+        case 32:
+                max_regions *= 2;
+                region_size = 16;
+                DBUG_ON(!is_shub2());
+        }
+
+        for (region = 0; region < max_regions; region++) {
+
+                if ((volatile int) xpc_exiting) {
+                        break;
+                }
+
+                dev_dbg(xpc_part, "searching region %d\n", region);
+
+                for (nasid = (region * region_size * 2);
+                     nasid < ((region + 1) * region_size * 2);
+                     nasid += 2) {
+
+                        if ((volatile int) xpc_exiting) {
+                                break;
+                        }
+
+                        dev_dbg(xpc_part, "checking nasid %d\n", nasid);
+
+
+                        if (XPC_NASID_IN_ARRAY(nasid, xpc_part_nasids)) {
+                                dev_dbg(xpc_part, "PROM indicates Nasid %d is "
+                                        "part of the local partition; skipping "
+                                        "region\n", nasid);
+                                break;
+                        }
+
+                        if (!(XPC_NASID_IN_ARRAY(nasid, xpc_mach_nasids))) {
+                                dev_dbg(xpc_part, "PROM indicates Nasid %d was "
+                                        "not on Numa-Link network at reset\n",
+                                        nasid);
+                                continue;
+                        }
+
+                        if (XPC_NASID_IN_ARRAY(nasid, discovered_nasids)) {
+                                dev_dbg(xpc_part, "Nasid %d is part of a "
+                                        "partition which was previously "
+                                        "discovered\n", nasid);
+                                continue;
+                        }
+
+
+                        /* pull over the reserved page structure */
+
+                        ret = xpc_get_remote_rp(nasid, discovered_nasids,
+                                              remote_rp, &remote_rp_pa);
+                        if (ret != xpcSuccess) {
+                                dev_dbg(xpc_part, "unable to get reserved page "
+                                        "from nasid %d, reason=%d\n", nasid,
+                                        ret);
+
+                                if (ret == xpcLocalPartid) {
+                                        break;
+                                }
+                                continue;
+                        }
+
+                        remote_vars_pa = remote_rp->vars_pa;
+
+                        partid = remote_rp->partid;
+                        part = &xpc_partitions[partid];
+
+
+                        /* pull over the cross partition variables */
+
+                        ret = xpc_get_remote_vars(remote_vars_pa, remote_vars);
+                        if (ret != xpcSuccess) {
+                                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, xpcPhysAddrRegFailed,
+                                                __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);
+                }
+        }
+
+        kfree(discovered_nasids);
+        kfree(remote_rp_base);
+}
+
+
+/*
+ * Given a partid, get the nasids owned by that partition from the
+ * remote partition's reserved page.
+ */
+enum xpc_retval
+xpc_initiate_partid_to_nasids(partid_t partid, void *nasid_mask)
+{
+        struct xpc_partition *part;
+        u64 part_nasid_pa;
+        int bte_res;
+
+
+        part = &xpc_partitions[partid];
+        if (part->remote_rp_pa == 0) {
+                return xpcPartitionDown;
+        }
+
+        memset(nasid_mask, 0, XP_NASID_MASK_BYTES);
+
+        part_nasid_pa = (u64) XPC_RP_PART_NASIDS(part->remote_rp_pa);
+
+        bte_res = xp_bte_copy(part_nasid_pa, (u64) nasid_mask,
+                        xp_nasid_mask_bytes, (BTE_NOTIFY | BTE_WACQUIRE), NULL);
+
+        return xpc_map_bte_errors(bte_res);
+}
+