sgi-xp: isolate xpc_vars_part structure to sn2 only

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

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, 560 insertions, 3 deletions

diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index 5a37348715c7..ee28e231dc47 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/drivers/misc/sgi-xp/xpc_sn2.c
@@ -14,12 +14,13 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/delay.h>
 #include <asm/uncached.h>
 #include <asm/sn/sn_sal.h>
 #include "xpc.h"
 
 struct xpc_vars *xpc_vars;
-struct xpc_vars_part *xpc_vars_part;
+static struct xpc_vars_part_sn2 *xpc_vars_part; /* >>> Add _sn2 suffix? */
 
 static enum xp_retval
 xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
@@ -33,7 +34,10 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
 
         rp->sn.vars_pa = __pa(xpc_vars);
 
-        xpc_vars_part = XPC_RP_VARS_PART(rp);
+        /* vars_part array follows immediately after vars */
+        xpc_vars_part = (struct xpc_vars_part_sn2 *)((u8 *)XPC_RP_VARS(rp) +
+                                                     XPC_RP_VARS_SIZE);
+
 
         /*
          * Before clearing xpc_vars, see if a page of AMOs had been previously
@@ -85,7 +89,7 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
         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) *
+        memset((u64 *)xpc_vars_part, 0, sizeof(struct xpc_vars_part_sn2) *
                xp_max_npartitions);
 
         /* initialize the activate IRQ related AMO variables */
@@ -99,10 +103,563 @@ xpc_rsvd_page_init_sn2(struct xpc_rsvd_page *rp)
         return xpSuccess;
 }
 
+/*
+ * Setup the infrastructure necessary to support XPartition Communication
+ * between the specified remote partition and the local one.
+ */
+static enum xp_retval
+xpc_setup_infrastructure_sn2(struct xpc_partition *part)
+{
+        enum xp_retval retval;
+        int ret;
+        int cpuid;
+        int ch_number;
+        struct xpc_channel *ch;
+        struct timer_list *timer;
+        short partid = XPC_PARTID(part);
+
+        /*
+         * Allocate all of the channel structures as a contiguous chunk of
+         * memory.
+         */
+        DBUG_ON(part->channels != NULL);
+        part->channels = kzalloc(sizeof(struct xpc_channel) * XPC_MAX_NCHANNELS,
+                                 GFP_KERNEL);
+        if (part->channels == NULL) {
+                dev_err(xpc_chan, "can't get memory for channels\n");
+                return xpNoMemory;
+        }
+
+        /* allocate all the required GET/PUT values */
+
+        part->local_GPs = xpc_kzalloc_cacheline_aligned(XPC_GP_SIZE,
+                                                        GFP_KERNEL,
+                                                        &part->local_GPs_base);
+        if (part->local_GPs == NULL) {
+                dev_err(xpc_chan, "can't get memory for local get/put "
+                        "values\n");
+                retval = xpNoMemory;
+                goto out_1;
+        }
+
+        part->remote_GPs = xpc_kzalloc_cacheline_aligned(XPC_GP_SIZE,
+                                                         GFP_KERNEL,
+                                                         &part->
+                                                         remote_GPs_base);
+        if (part->remote_GPs == NULL) {
+                dev_err(xpc_chan, "can't get memory for remote get/put "
+                        "values\n");
+                retval = xpNoMemory;
+                goto out_2;
+        }
+
+        part->remote_GPs_pa = 0;
+
+        /* allocate all the required open and close args */
+
+        part->local_openclose_args =
+            xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
+                                          &part->local_openclose_args_base);
+        if (part->local_openclose_args == NULL) {
+                dev_err(xpc_chan, "can't get memory for local connect args\n");
+                retval = xpNoMemory;
+                goto out_3;
+        }
+
+        part->remote_openclose_args =
+            xpc_kzalloc_cacheline_aligned(XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
+                                          &part->remote_openclose_args_base);
+        if (part->remote_openclose_args == NULL) {
+                dev_err(xpc_chan, "can't get memory for remote connect args\n");
+                retval = xpNoMemory;
+                goto out_4;
+        }
+
+        part->remote_openclose_args_pa = 0;
+
+        part->local_IPI_amo_va = xpc_IPI_init(partid);
+        part->local_IPI_amo = 0;
+        spin_lock_init(&part->IPI_lock);
+
+        part->remote_IPI_nasid = 0;
+        part->remote_IPI_phys_cpuid = 0;
+        part->remote_IPI_amo_va = NULL;
+
+        atomic_set(&part->channel_mgr_requests, 1);
+        init_waitqueue_head(&part->channel_mgr_wq);
+
+        sprintf(part->IPI_owner, "xpc%02d", partid);
+        ret = request_irq(SGI_XPC_NOTIFY, xpc_notify_IRQ_handler, IRQF_SHARED,
+                          part->IPI_owner, (void *)(u64)partid);
+        if (ret != 0) {
+                dev_err(xpc_chan, "can't register NOTIFY IRQ handler, "
+                        "errno=%d\n", -ret);
+                retval = xpLackOfResources;
+                goto out_5;
+        }
+
+        /* Setup a timer to check for dropped IPIs */
+        timer = &part->dropped_IPI_timer;
+        init_timer(timer);
+        timer->function = (void (*)(unsigned long))xpc_dropped_IPI_check;
+        timer->data = (unsigned long)part;
+        timer->expires = jiffies + XPC_P_DROPPED_IPI_WAIT_INTERVAL;
+        add_timer(timer);
+
+        part->nchannels = XPC_MAX_NCHANNELS;
+
+        atomic_set(&part->nchannels_active, 0);
+        atomic_set(&part->nchannels_engaged, 0);
+
+        for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
+                ch = &part->channels[ch_number];
+
+                ch->partid = partid;
+                ch->number = ch_number;
+                ch->flags = XPC_C_DISCONNECTED;
+
+                ch->local_GP = &part->local_GPs[ch_number];
+                ch->local_openclose_args =
+                    &part->local_openclose_args[ch_number];
+
+                atomic_set(&ch->kthreads_assigned, 0);
+                atomic_set(&ch->kthreads_idle, 0);
+                atomic_set(&ch->kthreads_active, 0);
+
+                atomic_set(&ch->references, 0);
+                atomic_set(&ch->n_to_notify, 0);
+
+                spin_lock_init(&ch->lock);
+                mutex_init(&ch->msg_to_pull_mutex);
+                init_completion(&ch->wdisconnect_wait);
+
+                atomic_set(&ch->n_on_msg_allocate_wq, 0);
+                init_waitqueue_head(&ch->msg_allocate_wq);
+                init_waitqueue_head(&ch->idle_wq);
+        }
+
+        /*
+         * With the setting of the partition setup_state to XPC_P_SETUP, we're
+         * declaring that this partition is ready to go.
+         */
+        part->setup_state = XPC_P_SETUP;
+
+        /*
+         * Setup the per partition specific variables required by the
+         * remote partition to establish channel connections with us.
+         *
+         * The setting of the magic # indicates that these per partition
+         * specific variables are ready to be used.
+         */
+        xpc_vars_part[partid].GPs_pa = __pa(part->local_GPs);
+        xpc_vars_part[partid].openclose_args_pa =
+            __pa(part->local_openclose_args);
+        xpc_vars_part[partid].IPI_amo_pa = __pa(part->local_IPI_amo_va);
+        cpuid = raw_smp_processor_id(); /* any CPU in this partition will do */
+        xpc_vars_part[partid].IPI_nasid = cpuid_to_nasid(cpuid);
+        xpc_vars_part[partid].IPI_phys_cpuid = cpu_physical_id(cpuid);
+        xpc_vars_part[partid].nchannels = part->nchannels;
+        xpc_vars_part[partid].magic = XPC_VP_MAGIC1;
+
+        return xpSuccess;
+
+        /* setup of infrastructure failed */
+out_5:
+        kfree(part->remote_openclose_args_base);
+        part->remote_openclose_args = NULL;
+out_4:
+        kfree(part->local_openclose_args_base);
+        part->local_openclose_args = NULL;
+out_3:
+        kfree(part->remote_GPs_base);
+        part->remote_GPs = NULL;
+out_2:
+        kfree(part->local_GPs_base);
+        part->local_GPs = NULL;
+out_1:
+        kfree(part->channels);
+        part->channels = NULL;
+        return retval;
+}
+
+/*
+ * Teardown the infrastructure necessary to support XPartition Communication
+ * between the specified remote partition and the local one.
+ */
+static void
+xpc_teardown_infrastructure_sn2(struct xpc_partition *part)
+{
+        short partid = XPC_PARTID(part);
+
+        /*
+         * We start off by making this partition inaccessible to local
+         * processes by marking it as no longer setup. Then we make it
+         * inaccessible to remote processes by clearing the XPC per partition
+         * specific variable's magic # (which indicates that these variables
+         * are no longer valid) and by ignoring all XPC notify IPIs sent to
+         * this partition.
+         */
+
+        DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
+        DBUG_ON(atomic_read(&part->nchannels_active) != 0);
+        DBUG_ON(part->setup_state != XPC_P_SETUP);
+        part->setup_state = XPC_P_WTEARDOWN;
+
+        xpc_vars_part[partid].magic = 0;
+
+        free_irq(SGI_XPC_NOTIFY, (void *)(u64)partid);
+
+        /*
+         * Before proceeding with the teardown we have to wait until all
+         * existing references cease.
+         */
+        wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));
+
+        /* now we can begin tearing down the infrastructure */
+
+        part->setup_state = XPC_P_TORNDOWN;
+
+        /* in case we've still got outstanding timers registered... */
+        del_timer_sync(&part->dropped_IPI_timer);
+
+        kfree(part->remote_openclose_args_base);
+        part->remote_openclose_args = NULL;
+        kfree(part->local_openclose_args_base);
+        part->local_openclose_args = NULL;
+        kfree(part->remote_GPs_base);
+        part->remote_GPs = NULL;
+        kfree(part->local_GPs_base);
+        part->local_GPs = NULL;
+        kfree(part->channels);
+        part->channels = NULL;
+        part->local_IPI_amo_va = NULL;
+}
+
+/*
+ * Create a wrapper that hides the underlying mechanism for pulling a cacheline
+ * (or multiple cachelines) from a remote partition.
+ *
+ * src must be a cacheline aligned physical address on the remote partition.
+ * dst must be a cacheline aligned virtual address on this partition.
+ * cnt must be cacheline sized
+ */
+/* >>> Replace this function by call to xp_remote_memcpy() or bte_copy()? */
+static enum xp_retval
+xpc_pull_remote_cachelines_sn2(struct xpc_partition *part, void *dst,
+                               const void *src, size_t cnt)
+{
+        enum xp_retval ret;
+
+        DBUG_ON((u64)src != L1_CACHE_ALIGN((u64)src));
+        DBUG_ON((u64)dst != L1_CACHE_ALIGN((u64)dst));
+        DBUG_ON(cnt != L1_CACHE_ALIGN(cnt));
+
+        if (part->act_state == XPC_P_DEACTIVATING)
+                return part->reason;
+
+        ret = xp_remote_memcpy(dst, src, cnt);
+        if (ret != xpSuccess) {
+                dev_dbg(xpc_chan, "xp_remote_memcpy() from partition %d failed,"
+                        " ret=%d\n", XPC_PARTID(part), ret);
+        }
+        return ret;
+}
+
+/*
+ * Pull the remote per partition specific variables from the specified
+ * partition.
+ */
+static enum xp_retval
+xpc_pull_remote_vars_part_sn2(struct xpc_partition *part)
+{
+        u8 buffer[L1_CACHE_BYTES * 2];
+        struct xpc_vars_part_sn2 *pulled_entry_cacheline =
+            (struct xpc_vars_part_sn2 *)L1_CACHE_ALIGN((u64)buffer);
+        struct xpc_vars_part_sn2 *pulled_entry;
+        u64 remote_entry_cacheline_pa, remote_entry_pa;
+        short partid = XPC_PARTID(part);
+        enum xp_retval ret;
+
+        /* pull the cacheline that contains the variables we're interested in */
+
+        DBUG_ON(part->remote_vars_part_pa !=
+                L1_CACHE_ALIGN(part->remote_vars_part_pa));
+        DBUG_ON(sizeof(struct xpc_vars_part_sn2) != L1_CACHE_BYTES / 2);
+
+        remote_entry_pa = part->remote_vars_part_pa +
+            sn_partition_id * sizeof(struct xpc_vars_part_sn2);
+
+        remote_entry_cacheline_pa = (remote_entry_pa & ~(L1_CACHE_BYTES - 1));
+
+        pulled_entry = (struct xpc_vars_part_sn2 *)((u64)pulled_entry_cacheline
+                                                    + (remote_entry_pa &
+                                                    (L1_CACHE_BYTES - 1)));
+
+        ret = xpc_pull_remote_cachelines_sn2(part, pulled_entry_cacheline,
+                                             (void *)remote_entry_cacheline_pa,
+                                             L1_CACHE_BYTES);
+        if (ret != xpSuccess) {
+                dev_dbg(xpc_chan, "failed to pull XPC vars_part from "
+                        "partition %d, ret=%d\n", partid, ret);
+                return ret;
+        }
+
+        /* see if they've been set up yet */
+
+        if (pulled_entry->magic != XPC_VP_MAGIC1 &&
+            pulled_entry->magic != XPC_VP_MAGIC2) {
+
+                if (pulled_entry->magic != 0) {
+                        dev_dbg(xpc_chan, "partition %d's XPC vars_part for "
+                                "partition %d has bad magic value (=0x%lx)\n",
+                                partid, sn_partition_id, pulled_entry->magic);
+                        return xpBadMagic;
+                }
+
+                /* they've not been initialized yet */
+                return xpRetry;
+        }
+
+        if (xpc_vars_part[partid].magic == XPC_VP_MAGIC1) {
+
+                /* validate the variables */
+
+                if (pulled_entry->GPs_pa == 0 ||
+                    pulled_entry->openclose_args_pa == 0 ||
+                    pulled_entry->IPI_amo_pa == 0) {
+
+                        dev_err(xpc_chan, "partition %d's XPC vars_part for "
+                                "partition %d are not valid\n", partid,
+                                sn_partition_id);
+                        return xpInvalidAddress;
+                }
+
+                /* the variables we imported look to be valid */
+
+                part->remote_GPs_pa = pulled_entry->GPs_pa;
+                part->remote_openclose_args_pa =
+                    pulled_entry->openclose_args_pa;
+                part->remote_IPI_amo_va =
+                    (AMO_t *)__va(pulled_entry->IPI_amo_pa);
+                part->remote_IPI_nasid = pulled_entry->IPI_nasid;
+                part->remote_IPI_phys_cpuid = pulled_entry->IPI_phys_cpuid;
+
+                if (part->nchannels > pulled_entry->nchannels)
+                        part->nchannels = pulled_entry->nchannels;
+
+                /* let the other side know that we've pulled their variables */
+
+                xpc_vars_part[partid].magic = XPC_VP_MAGIC2;
+        }
+
+        if (pulled_entry->magic == XPC_VP_MAGIC1)
+                return xpRetry;
+
+        return xpSuccess;
+}
+
+/*
+ * Establish first contact with the remote partititon. This involves pulling
+ * the XPC per partition variables from the remote partition and waiting for
+ * the remote partition to pull ours.
+ */
+static enum xp_retval
+xpc_make_first_contact_sn2(struct xpc_partition *part)
+{
+        enum xp_retval ret;
+
+        while ((ret = xpc_pull_remote_vars_part_sn2(part)) != xpSuccess) {
+                if (ret != xpRetry) {
+                        XPC_DEACTIVATE_PARTITION(part, ret);
+                        return ret;
+                }
+
+                dev_dbg(xpc_part, "waiting to make first contact with "
+                        "partition %d\n", XPC_PARTID(part));
+
+                /* wait a 1/4 of a second or so */
+                (void)msleep_interruptible(250);
+
+                if (part->act_state == XPC_P_DEACTIVATING)
+                        return part->reason;
+        }
+
+        return xpSuccess;
+}
+
+/*
+ * Get the IPI flags and pull the openclose args and/or remote GPs as needed.
+ */
+static u64
+xpc_get_IPI_flags_sn2(struct xpc_partition *part)
+{
+        unsigned long irq_flags;
+        u64 IPI_amo;
+        enum xp_retval ret;
+
+        /*
+         * See if there are any IPI flags to be handled.
+         */
+
+        spin_lock_irqsave(&part->IPI_lock, irq_flags);
+        IPI_amo = part->local_IPI_amo;
+        if (IPI_amo != 0)
+                part->local_IPI_amo = 0;
+
+        spin_unlock_irqrestore(&part->IPI_lock, irq_flags);
+
+        if (XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(IPI_amo)) {
+                ret = xpc_pull_remote_cachelines_sn2(part,
+                                                    part->remote_openclose_args,
+                                                     (void *)part->
+                                                     remote_openclose_args_pa,
+                                                     XPC_OPENCLOSE_ARGS_SIZE);
+                if (ret != xpSuccess) {
+                        XPC_DEACTIVATE_PARTITION(part, ret);
+
+                        dev_dbg(xpc_chan, "failed to pull openclose args from "
+                                "partition %d, ret=%d\n", XPC_PARTID(part),
+                                ret);
+
+                        /* don't bother processing IPIs anymore */
+                        IPI_amo = 0;
+                }
+        }
+
+        if (XPC_ANY_MSG_IPI_FLAGS_SET(IPI_amo)) {
+                ret = xpc_pull_remote_cachelines_sn2(part, part->remote_GPs,
+                                                    (void *)part->remote_GPs_pa,
+                                                     XPC_GP_SIZE);
+                if (ret != xpSuccess) {
+                        XPC_DEACTIVATE_PARTITION(part, ret);
+
+                        dev_dbg(xpc_chan, "failed to pull GPs from partition "
+                                "%d, ret=%d\n", XPC_PARTID(part), ret);
+
+                        /* don't bother processing IPIs anymore */
+                        IPI_amo = 0;
+                }
+        }
+
+        return IPI_amo;
+}
+
+static struct xpc_msg *
+xpc_pull_remote_msg_sn2(struct xpc_channel *ch, s64 get)
+{
+        struct xpc_partition *part = &xpc_partitions[ch->partid];
+        struct xpc_msg *remote_msg, *msg;
+        u32 msg_index, nmsgs;
+        u64 msg_offset;
+        enum xp_retval ret;
+
+        if (mutex_lock_interruptible(&ch->msg_to_pull_mutex) != 0) {
+                /* we were interrupted by a signal */
+                return NULL;
+        }
+
+        while (get >= ch->next_msg_to_pull) {
+
+                /* pull as many messages as are ready and able to be pulled */
+
+                msg_index = ch->next_msg_to_pull % ch->remote_nentries;
+
+                DBUG_ON(ch->next_msg_to_pull >= ch->w_remote_GP.put);
+                nmsgs = ch->w_remote_GP.put - ch->next_msg_to_pull;
+                if (msg_index + nmsgs > ch->remote_nentries) {
+                        /* ignore the ones that wrap the msg queue for now */
+                        nmsgs = ch->remote_nentries - msg_index;
+                }
+
+                msg_offset = msg_index * ch->msg_size;
+                msg = (struct xpc_msg *)((u64)ch->remote_msgqueue + msg_offset);
+                remote_msg = (struct xpc_msg *)(ch->remote_msgqueue_pa +
+                                                msg_offset);
+
+                ret = xpc_pull_remote_cachelines_sn2(part, msg, remote_msg,
+                                                     nmsgs * ch->msg_size);
+                if (ret != xpSuccess) {
+
+                        dev_dbg(xpc_chan, "failed to pull %d msgs starting with"
+                                " msg %ld from partition %d, channel=%d, "
+                                "ret=%d\n", nmsgs, ch->next_msg_to_pull,
+                                ch->partid, ch->number, ret);
+
+                        XPC_DEACTIVATE_PARTITION(part, ret);
+
+                        mutex_unlock(&ch->msg_to_pull_mutex);
+                        return NULL;
+                }
+
+                ch->next_msg_to_pull += nmsgs;
+        }
+
+        mutex_unlock(&ch->msg_to_pull_mutex);
+
+        /* return the message we were looking for */
+        msg_offset = (get % ch->remote_nentries) * ch->msg_size;
+        msg = (struct xpc_msg *)((u64)ch->remote_msgqueue + msg_offset);
+
+        return msg;
+}
+
+/*
+ * Get a message to be delivered.
+ */
+static struct xpc_msg *
+xpc_get_deliverable_msg_sn2(struct xpc_channel *ch)
+{
+        struct xpc_msg *msg = NULL;
+        s64 get;
+
+        do {
+                if (ch->flags & XPC_C_DISCONNECTING)
+                        break;
+
+                get = ch->w_local_GP.get;
+                rmb();  /* guarantee that .get loads before .put */
+                if (get == ch->w_remote_GP.put)
+                        break;
+
+                /* There are messages waiting to be pulled and delivered.
+                 * We need to try to secure one for ourselves. We'll do this
+                 * by trying to increment w_local_GP.get and hope that no one
+                 * else beats us to it. If they do, we'll we'll simply have
+                 * to try again for the next one.
+                 */
+
+                if (cmpxchg(&ch->w_local_GP.get, get, get + 1) == get) {
+                        /* we got the entry referenced by get */
+
+                        dev_dbg(xpc_chan, "w_local_GP.get changed to %ld, "
+                                "partid=%d, channel=%d\n", get + 1,
+                                ch->partid, ch->number);
+
+                        /* pull the message from the remote partition */
+
+                        msg = xpc_pull_remote_msg_sn2(ch, get);
+
+                        DBUG_ON(msg != NULL && msg->number != get);
+                        DBUG_ON(msg != NULL && (msg->flags & XPC_M_DONE));
+                        DBUG_ON(msg != NULL && !(msg->flags & XPC_M_READY));
+
+                        break;
+                }
+
+        } while (1);
+
+        return msg;
+}
+
 void
 xpc_init_sn2(void)
 {
         xpc_rsvd_page_init = xpc_rsvd_page_init_sn2;
+        xpc_setup_infrastructure = xpc_setup_infrastructure_sn2;
+        xpc_teardown_infrastructure = xpc_teardown_infrastructure_sn2;
+        xpc_make_first_contact = xpc_make_first_contact_sn2;
+        xpc_get_IPI_flags = xpc_get_IPI_flags_sn2;
+        xpc_get_deliverable_msg = xpc_get_deliverable_msg_sn2;
 }
 
 void