x86, UV: Disable BAU on network congestion

[deliverable/linux.git] / arch / x86 / kernel / tlb_uv.c

/*
 *      SGI UltraViolet TLB flush routines.
 *
 *      (c) 2008-2010 Cliff Wickman <cpw@sgi.com>, SGI.
 *
 *      This code is released under the GNU General Public License version 2 or
 *      later.
 */
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/slab.h>

#include <asm/mmu_context.h>
#include <asm/uv/uv.h>
#include <asm/uv/uv_mmrs.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/uv_bau.h>
#include <asm/apic.h>
#include <asm/idle.h>
#include <asm/tsc.h>
#include <asm/irq_vectors.h>
#include <asm/timer.h>

struct msg_desc {
        struct bau_payload_queue_entry *msg;
        int msg_slot;
        int sw_ack_slot;
        struct bau_payload_queue_entry *va_queue_first;
        struct bau_payload_queue_entry *va_queue_last;
};

/* timeouts in nanoseconds (indexed by UVH_AGING_PRESCALE_SEL urgency7 30:28) */
static int timeout_base_ns[] = {
                20,
                160,
                1280,
                10240,
                81920,
                655360,
                5242880,
                167772160
};
static int timeout_us;
static int nobau;
static int baudisabled;
static spinlock_t disable_lock;
static cycles_t congested_cycles;

/* tunables: */
static int max_bau_concurrent = MAX_BAU_CONCURRENT;
static int max_bau_concurrent_constant = MAX_BAU_CONCURRENT;
static int plugged_delay = PLUGGED_DELAY;
static int plugsb4reset = PLUGSB4RESET;
static int timeoutsb4reset = TIMEOUTSB4RESET;
static int ipi_reset_limit = IPI_RESET_LIMIT;
static int complete_threshold = COMPLETE_THRESHOLD;
static int congested_response_us = CONGESTED_RESPONSE_US;
static int congested_reps = CONGESTED_REPS;
static int congested_period = CONGESTED_PERIOD;
static struct dentry *tunables_dir;
static struct dentry *tunables_file;

static int __init setup_nobau(char *arg)
{
        nobau = 1;
        return 0;
}
early_param("nobau", setup_nobau);

/* base pnode in this partition */
static int uv_partition_base_pnode __read_mostly;
/* position of pnode (which is nasid>>1): */
static int uv_nshift __read_mostly;
static unsigned long uv_mmask __read_mostly;

static DEFINE_PER_CPU(struct ptc_stats, ptcstats);
static DEFINE_PER_CPU(struct bau_control, bau_control);
static DEFINE_PER_CPU(cpumask_var_t, uv_flush_tlb_mask);

struct reset_args {
        int sender;
};

/*
 * Determine the first node on a uvhub. 'Nodes' are used for kernel
 * memory allocation.
 */
static int __init uvhub_to_first_node(int uvhub)
{
        int node, b;

        for_each_online_node(node) {
                b = uv_node_to_blade_id(node);
                if (uvhub == b)
                        return node;
        }
        return -1;
}

/*
 * Determine the apicid of the first cpu on a uvhub.
 */
static int __init uvhub_to_first_apicid(int uvhub)
{
        int cpu;

        for_each_present_cpu(cpu)
                if (uvhub == uv_cpu_to_blade_id(cpu))
                        return per_cpu(x86_cpu_to_apicid, cpu);
        return -1;
}

/*
 * Free a software acknowledge hardware resource by clearing its Pending
 * bit. This will return a reply to the sender.
 * If the message has timed out, a reply has already been sent by the
 * hardware but the resource has not been released. In that case our
 * clear of the Timeout bit (as well) will free the resource. No reply will
 * be sent (the hardware will only do one reply per message).
 */
static inline void uv_reply_to_message(struct msg_desc *mdp,
                                       struct bau_control *bcp)
{
        unsigned long dw;
        struct bau_payload_queue_entry *msg;

        msg = mdp->msg;
        if (!msg->canceled) {
                dw = (msg->sw_ack_vector << UV_SW_ACK_NPENDING) |
                                                msg->sw_ack_vector;
                uv_write_local_mmr(
                                UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS, dw);
        }
        msg->replied_to = 1;
        msg->sw_ack_vector = 0;
}

/*
 * Process the receipt of a RETRY message
 */
static inline void uv_bau_process_retry_msg(struct msg_desc *mdp,
                                            struct bau_control *bcp)
{
        int i;
        int cancel_count = 0;
        int slot2;
        unsigned long msg_res;
        unsigned long mmr = 0;
        struct bau_payload_queue_entry *msg;
        struct bau_payload_queue_entry *msg2;
        struct ptc_stats *stat;

        msg = mdp->msg;
        stat = &per_cpu(ptcstats, bcp->cpu);
        stat->d_retries++;
        /*
         * cancel any message from msg+1 to the retry itself
         */
        for (msg2 = msg+1, i = 0; i < DEST_Q_SIZE; msg2++, i++) {
                if (msg2 > mdp->va_queue_last)
                        msg2 = mdp->va_queue_first;
                if (msg2 == msg)
                        break;

                /* same conditions for cancellation as uv_do_reset */
                if ((msg2->replied_to == 0) && (msg2->canceled == 0) &&
                    (msg2->sw_ack_vector) && ((msg2->sw_ack_vector &
                        msg->sw_ack_vector) == 0) &&
                    (msg2->sending_cpu == msg->sending_cpu) &&
                    (msg2->msg_type != MSG_NOOP)) {
                        slot2 = msg2 - mdp->va_queue_first;
                        mmr = uv_read_local_mmr
                                (UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE);
                        msg_res = ((msg2->sw_ack_vector << 8) |
                                   msg2->sw_ack_vector);
                        /*
                         * This is a message retry; clear the resources held
                         * by the previous message only if they timed out.
                         * If it has not timed out we have an unexpected
                         * situation to report.
                         */
                        if (mmr & (msg_res << 8)) {
                                /*
                                 * is the resource timed out?
                                 * make everyone ignore the cancelled message.
                                 */
                                msg2->canceled = 1;
                                stat->d_canceled++;
                                cancel_count++;
                                uv_write_local_mmr(
                                    UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS,
                                        (msg_res << 8) | msg_res);
                        } else
                                printk(KERN_INFO "note bau retry: no effect\n");
                }
        }
        if (!cancel_count)
                stat->d_nocanceled++;
}

/*
 * Do all the things a cpu should do for a TLB shootdown message.
 * Other cpu's may come here at the same time for this message.
 */
static void uv_bau_process_message(struct msg_desc *mdp,
                                   struct bau_control *bcp)
{
        int msg_ack_count;
        short socket_ack_count = 0;
        struct ptc_stats *stat;
        struct bau_payload_queue_entry *msg;
        struct bau_control *smaster = bcp->socket_master;

        /*
         * This must be a normal message, or retry of a normal message
         */
        msg = mdp->msg;
        stat = &per_cpu(ptcstats, bcp->cpu);
        if (msg->address == TLB_FLUSH_ALL) {
                local_flush_tlb();
                stat->d_alltlb++;
        } else {
                __flush_tlb_one(msg->address);
                stat->d_onetlb++;
        }
        stat->d_requestee++;

        /*
         * One cpu on each uvhub has the additional job on a RETRY
         * of releasing the resource held by the message that is
         * being retried.  That message is identified by sending
         * cpu number.
         */
        if (msg->msg_type == MSG_RETRY && bcp == bcp->uvhub_master)
                uv_bau_process_retry_msg(mdp, bcp);

        /*
         * This is a sw_ack message, so we have to reply to it.
         * Count each responding cpu on the socket. This avoids
         * pinging the count's cache line back and forth between
         * the sockets.
         */
        socket_ack_count = atomic_add_short_return(1, (struct atomic_short *)
                        &smaster->socket_acknowledge_count[mdp->msg_slot]);
        if (socket_ack_count == bcp->cpus_in_socket) {
                /*
                 * Both sockets dump their completed count total into
                 * the message's count.
                 */
                smaster->socket_acknowledge_count[mdp->msg_slot] = 0;
                msg_ack_count = atomic_add_short_return(socket_ack_count,
                                (struct atomic_short *)&msg->acknowledge_count);

                if (msg_ack_count == bcp->cpus_in_uvhub) {
                        /*
                         * All cpus in uvhub saw it; reply
                         */
                        uv_reply_to_message(mdp, bcp);
                }
        }

        return;
}

/*
 * Determine the first cpu on a uvhub.
 */
static int uvhub_to_first_cpu(int uvhub)
{
        int cpu;
        for_each_present_cpu(cpu)
                if (uvhub == uv_cpu_to_blade_id(cpu))
                        return cpu;
        return -1;
}

/*
 * Last resort when we get a large number of destination timeouts is
 * to clear resources held by a given cpu.
 * Do this with IPI so that all messages in the BAU message queue
 * can be identified by their nonzero sw_ack_vector field.
 *
 * This is entered for a single cpu on the uvhub.
 * The sender want's this uvhub to free a specific message's
 * sw_ack resources.
 */
static void
uv_do_reset(void *ptr)
{
        int i;
        int slot;
        int count = 0;
        unsigned long mmr;
        unsigned long msg_res;
        struct bau_control *bcp;
        struct reset_args *rap;
        struct bau_payload_queue_entry *msg;
        struct ptc_stats *stat;

        bcp = &per_cpu(bau_control, smp_processor_id());
        rap = (struct reset_args *)ptr;
        stat = &per_cpu(ptcstats, bcp->cpu);
        stat->d_resets++;

        /*
         * We're looking for the given sender, and
         * will free its sw_ack resource.
         * If all cpu's finally responded after the timeout, its
         * message 'replied_to' was set.
         */
        for (msg = bcp->va_queue_first, i = 0; i < DEST_Q_SIZE; msg++, i++) {
                /* uv_do_reset: same conditions for cancellation as
                   uv_bau_process_retry_msg() */
                if ((msg->replied_to == 0) &&
                    (msg->canceled == 0) &&
                    (msg->sending_cpu == rap->sender) &&
                    (msg->sw_ack_vector) &&
                    (msg->msg_type != MSG_NOOP)) {
                        /*
                         * make everyone else ignore this message
                         */
                        msg->canceled = 1;
                        slot = msg - bcp->va_queue_first;
                        count++;
                        /*
                         * only reset the resource if it is still pending
                         */
                        mmr = uv_read_local_mmr
                                        (UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE);
                        msg_res = ((msg->sw_ack_vector << 8) |
                                                   msg->sw_ack_vector);
                        if (mmr & msg_res) {
                                stat->d_rcanceled++;
                                uv_write_local_mmr(
                                    UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS,
                                                        msg_res);
                        }
                }
        }
        return;
}

/*
 * Use IPI to get all target uvhubs to release resources held by
 * a given sending cpu number.
 */
static void uv_reset_with_ipi(struct bau_target_uvhubmask *distribution,
                              int sender)
{
        int uvhub;
        int cpu;
        cpumask_t mask;
        struct reset_args reset_args;

        reset_args.sender = sender;

        cpus_clear(mask);
        /* find a single cpu for each uvhub in this distribution mask */
        for (uvhub = 0;
                    uvhub < sizeof(struct bau_target_uvhubmask) * BITSPERBYTE;
                    uvhub++) {
                if (!bau_uvhub_isset(uvhub, distribution))
                        continue;
                /* find a cpu for this uvhub */
                cpu = uvhub_to_first_cpu(uvhub);
                cpu_set(cpu, mask);
        }
        /* IPI all cpus; Preemption is already disabled */
        smp_call_function_many(&mask, uv_do_reset, (void *)&reset_args, 1);
        return;
}

static inline unsigned long
cycles_2_us(unsigned long long cyc)
{
        unsigned long long ns;
        unsigned long us;
        ns =  (cyc * per_cpu(cyc2ns, smp_processor_id()))
                                                >> CYC2NS_SCALE_FACTOR;
        us = ns / 1000;
        return us;
}

/*
 * wait for all cpus on this hub to finish their sends and go quiet
 * leaves uvhub_quiesce set so that no new broadcasts are started by
 * bau_flush_send_and_wait()
 */
static inline void
quiesce_local_uvhub(struct bau_control *hmaster)
{
        atomic_add_short_return(1, (struct atomic_short *)
                 &hmaster->uvhub_quiesce);
}

/*
 * mark this quiet-requestor as done
 */
static inline void
end_uvhub_quiesce(struct bau_control *hmaster)
{
        atomic_add_short_return(-1, (struct atomic_short *)
                &hmaster->uvhub_quiesce);
}

/*
 * Wait for completion of a broadcast software ack message
 * return COMPLETE, RETRY(PLUGGED or TIMEOUT) or GIVEUP
 */
static int uv_wait_completion(struct bau_desc *bau_desc,
        unsigned long mmr_offset, int right_shift, int this_cpu,
        struct bau_control *bcp, struct bau_control *smaster, long try)
{
        int relaxes = 0;
        unsigned long descriptor_status;
        unsigned long mmr;
        unsigned long mask;
        cycles_t ttime;
        cycles_t timeout_time;
        struct ptc_stats *stat = &per_cpu(ptcstats, this_cpu);
        struct bau_control *hmaster;

        hmaster = bcp->uvhub_master;
        timeout_time = get_cycles() + bcp->timeout_interval;

        /* spin on the status MMR, waiting for it to go idle */
        while ((descriptor_status = (((unsigned long)
                uv_read_local_mmr(mmr_offset) >>
                        right_shift) & UV_ACT_STATUS_MASK)) !=
                        DESC_STATUS_IDLE) {
                /*
                 * Our software ack messages may be blocked because there are
                 * no swack resources available.  As long as none of them
                 * has timed out hardware will NACK our message and its
                 * state will stay IDLE.
                 */
                if (descriptor_status == DESC_STATUS_SOURCE_TIMEOUT) {
                        stat->s_stimeout++;
                        return FLUSH_GIVEUP;
                } else if (descriptor_status ==
                                        DESC_STATUS_DESTINATION_TIMEOUT) {
                        stat->s_dtimeout++;
                        ttime = get_cycles();

                        /*
                         * Our retries may be blocked by all destination
                         * swack resources being consumed, and a timeout
                         * pending.  In that case hardware returns the
                         * ERROR that looks like a destination timeout.
                         */
                        if (cycles_2_us(ttime - bcp->send_message) <
                                                        timeout_us) {
                                bcp->conseccompletes = 0;
                                return FLUSH_RETRY_PLUGGED;
                        }

                        bcp->conseccompletes = 0;
                        return FLUSH_RETRY_TIMEOUT;
                } else {
                        /*
                         * descriptor_status is still BUSY
                         */
                        cpu_relax();
                        relaxes++;
                        if (relaxes >= 10000) {
                                relaxes = 0;
                                if (get_cycles() > timeout_time) {
                                        quiesce_local_uvhub(hmaster);

                                        /* single-thread the register change */
                                        spin_lock(&hmaster->masks_lock);
                                        mmr = uv_read_local_mmr(mmr_offset);
                                        mask = 0UL;
                                        mask |= (3UL < right_shift);
                                        mask = ~mask;
                                        mmr &= mask;
                                        uv_write_local_mmr(mmr_offset, mmr);
                                        spin_unlock(&hmaster->masks_lock);
                                        end_uvhub_quiesce(hmaster);
                                        stat->s_busy++;
                                        return FLUSH_GIVEUP;
                                }
                        }
                }
        }
        bcp->conseccompletes++;
        return FLUSH_COMPLETE;
}

static inline cycles_t
sec_2_cycles(unsigned long sec)
{
        unsigned long ns;
        cycles_t cyc;

        ns = sec * 1000000000;
        cyc = (ns << CYC2NS_SCALE_FACTOR)/(per_cpu(cyc2ns, smp_processor_id()));
        return cyc;
}

/*
 * conditionally add 1 to *v, unless *v is >= u
 * return 0 if we cannot add 1 to *v because it is >= u
 * return 1 if we can add 1 to *v because it is < u
 * the add is atomic
 *
 * This is close to atomic_add_unless(), but this allows the 'u' value
 * to be lowered below the current 'v'.  atomic_add_unless can only stop
 * on equal.
 */
static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
{
        spin_lock(lock);
        if (atomic_read(v) >= u) {
                spin_unlock(lock);
                return 0;
        }
        atomic_inc(v);
        spin_unlock(lock);
        return 1;
}

/*
 * Completions are taking a very long time due to a congested numalink
 * network.
 */
static void
disable_for_congestion(struct bau_control *bcp, struct ptc_stats *stat)
{
        int tcpu;
        struct bau_control *tbcp;

        /* let only one cpu do this disabling */
        spin_lock(&disable_lock);
        if (!baudisabled && bcp->period_requests &&
            ((bcp->period_time / bcp->period_requests) > congested_cycles)) {
                /* it becomes this cpu's job to turn on the use of the
                   BAU again */
                baudisabled = 1;
                bcp->set_bau_off = 1;
                bcp->set_bau_on_time = get_cycles() +
                        sec_2_cycles(bcp->congested_period);
                stat->s_bau_disabled++;
                for_each_present_cpu(tcpu) {
                        tbcp = &per_cpu(bau_control, tcpu);
                                tbcp->baudisabled = 1;
                }
        }
        spin_unlock(&disable_lock);
}

/**
 * uv_flush_send_and_wait
 *
 * Send a broadcast and wait for it to complete.
 *
 * The flush_mask contains the cpus the broadcast is to be sent to, plus
 * cpus that are on the local uvhub.
 *
 * Returns NULL if all flushing represented in the mask was done. The mask
 * is zeroed.
 * Returns @flush_mask if some remote flushing remains to be done. The
 * mask will have some bits still set, representing any cpus on the local
 * uvhub (not current cpu) and any on remote uvhubs if the broadcast failed.
 */
const struct cpumask *uv_flush_send_and_wait(struct bau_desc *bau_desc,
                                             struct cpumask *flush_mask,
                                             struct bau_control *bcp)
{
        int right_shift;
        int uvhub;
        int bit;
        int completion_status = 0;
        int seq_number = 0;
        long try = 0;
        int cpu = bcp->uvhub_cpu;
        int this_cpu = bcp->cpu;
        int this_uvhub = bcp->uvhub;
        unsigned long mmr_offset;
        unsigned long index;
        cycles_t time1;
        cycles_t time2;
        cycles_t elapsed;
        struct ptc_stats *stat = &per_cpu(ptcstats, bcp->cpu);
        struct bau_control *smaster = bcp->socket_master;
        struct bau_control *hmaster = bcp->uvhub_master;

        /*
         * Spin here while there are hmaster->max_bau_concurrent or more active
         * descriptors. This is the per-uvhub 'throttle'.
         */
        if (!atomic_inc_unless_ge(&hmaster->uvhub_lock,
                        &hmaster->active_descriptor_count,
                        hmaster->max_bau_concurrent)) {
                stat->s_throttles++;
                do {
                        cpu_relax();
                } while (!atomic_inc_unless_ge(&hmaster->uvhub_lock,
                        &hmaster->active_descriptor_count,
                        hmaster->max_bau_concurrent));
        }

        while (hmaster->uvhub_quiesce)
                cpu_relax();

        if (cpu < UV_CPUS_PER_ACT_STATUS) {
                mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_0;
                right_shift = cpu * UV_ACT_STATUS_SIZE;
        } else {
                mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_1;
                right_shift =
                    ((cpu - UV_CPUS_PER_ACT_STATUS) * UV_ACT_STATUS_SIZE);
        }
        time1 = get_cycles();
        do {
                /*
                 * Every message from any given cpu gets a unique message
                 * sequence number. But retries use that same number.
                 * Our message may have timed out at the destination because
                 * all sw-ack resources are in use and there is a timeout
                 * pending there.  In that case, our last send never got
                 * placed into the queue and we need to persist until it
                 * does.
                 *
                 * Make any retry a type MSG_RETRY so that the destination will
                 * free any resource held by a previous message from this cpu.
                 */
                if (try == 0) {
                        /* use message type set by the caller the first time */
                        seq_number = bcp->message_number++;
                } else {
                        /* use RETRY type on all the rest; same sequence */
                        bau_desc->header.msg_type = MSG_RETRY;
                        stat->s_retry_messages++;
                }
                bau_desc->header.sequence = seq_number;
                index = (1UL << UVH_LB_BAU_SB_ACTIVATION_CONTROL_PUSH_SHFT) |
                        bcp->uvhub_cpu;
                bcp->send_message = get_cycles();

                uv_write_local_mmr(UVH_LB_BAU_SB_ACTIVATION_CONTROL, index);

                try++;
                completion_status = uv_wait_completion(bau_desc, mmr_offset,
                        right_shift, this_cpu, bcp, smaster, try);

                if (completion_status == FLUSH_RETRY_PLUGGED) {
                        /*
                         * Our retries may be blocked by all destination swack
                         * resources being consumed, and a timeout pending. In
                         * that case hardware immediately returns the ERROR
                         * that looks like a destination timeout.
                         */
                        udelay(bcp->plugged_delay);
                        bcp->plugged_tries++;
                        if (bcp->plugged_tries >= bcp->plugsb4reset) {
                                bcp->plugged_tries = 0;
                                quiesce_local_uvhub(hmaster);
                                spin_lock(&hmaster->queue_lock);
                                uv_reset_with_ipi(&bau_desc->distribution,
                                                        this_cpu);
                                spin_unlock(&hmaster->queue_lock);
                                end_uvhub_quiesce(hmaster);
                                bcp->ipi_attempts++;
                                stat->s_resets_plug++;
                        }
                } else if (completion_status == FLUSH_RETRY_TIMEOUT) {
                        hmaster->max_bau_concurrent = 1;
                        bcp->timeout_tries++;
                        udelay(TIMEOUT_DELAY);
                        if (bcp->timeout_tries >= bcp->timeoutsb4reset) {
                                bcp->timeout_tries = 0;
                                quiesce_local_uvhub(hmaster);
                                spin_lock(&hmaster->queue_lock);
                                uv_reset_with_ipi(&bau_desc->distribution,
                                                                this_cpu);
                                spin_unlock(&hmaster->queue_lock);
                                end_uvhub_quiesce(hmaster);
                                bcp->ipi_attempts++;
                                stat->s_resets_timeout++;
                        }
                }
                if (bcp->ipi_attempts >= bcp->ipi_reset_limit) {
                        bcp->ipi_attempts = 0;
                        completion_status = FLUSH_GIVEUP;
                        break;
                }
                cpu_relax();
        } while ((completion_status == FLUSH_RETRY_PLUGGED) ||
                 (completion_status == FLUSH_RETRY_TIMEOUT));
        time2 = get_cycles();

        bcp->plugged_tries = 0;
        bcp->timeout_tries = 0;

        if ((completion_status == FLUSH_COMPLETE) &&
            (bcp->conseccompletes > bcp->complete_threshold) &&
            (hmaster->max_bau_concurrent <
                                        hmaster->max_bau_concurrent_constant))
                        hmaster->max_bau_concurrent++;

        /*
         * hold any cpu not timing out here; no other cpu currently held by
         * the 'throttle' should enter the activation code
         */
        while (hmaster->uvhub_quiesce)
                cpu_relax();
        atomic_dec(&hmaster->active_descriptor_count);

        /* guard against cycles wrap */
        if (time2 > time1) {
                elapsed = time2 - time1;
                stat->s_time += elapsed;
                if ((completion_status == FLUSH_COMPLETE) && (try == 1)) {
                        bcp->period_requests++;
                        bcp->period_time += elapsed;
                        if ((elapsed > congested_cycles) &&
                            (bcp->period_requests > bcp->congested_reps)) {
                                disable_for_congestion(bcp, stat);
                        }
                }
        } else
                stat->s_requestor--; /* don't count this one */
        if (completion_status == FLUSH_COMPLETE && try > 1)
                stat->s_retriesok++;
        else if (completion_status == FLUSH_GIVEUP) {
                /*
                 * Cause the caller to do an IPI-style TLB shootdown on
                 * the target cpu's, all of which are still in the mask.
                 */
                stat->s_giveup++;
                return flush_mask;
        }

        /*
         * Success, so clear the remote cpu's from the mask so we don't
         * use the IPI method of shootdown on them.
         */
        for_each_cpu(bit, flush_mask) {
                uvhub = uv_cpu_to_blade_id(bit);
                if (uvhub == this_uvhub)
                        continue;
                cpumask_clear_cpu(bit, flush_mask);
        }
        if (!cpumask_empty(flush_mask))
                return flush_mask;

        return NULL;
}

/**
 * uv_flush_tlb_others - globally purge translation cache of a virtual
 * address or all TLB's
 * @cpumask: mask of all cpu's in which the address is to be removed
 * @mm: mm_struct containing virtual address range
 * @va: virtual address to be removed (or TLB_FLUSH_ALL for all TLB's on cpu)
 * @cpu: the current cpu
 *
 * This is the entry point for initiating any UV global TLB shootdown.
 *
 * Purges the translation caches of all specified processors of the given
 * virtual address, or purges all TLB's on specified processors.
 *
 * The caller has derived the cpumask from the mm_struct.  This function
 * is called only if there are bits set in the mask. (e.g. flush_tlb_page())
 *
 * The cpumask is converted into a uvhubmask of the uvhubs containing
 * those cpus.
 *
 * Note that this function should be called with preemption disabled.
 *
 * Returns NULL if all remote flushing was done.
 * Returns pointer to cpumask if some remote flushing remains to be
 * done.  The returned pointer is valid till preemption is re-enabled.
 */
const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
                                          struct mm_struct *mm,
                                          unsigned long va, unsigned int cpu)
{
        int remotes;
        int tcpu;
        int uvhub;
        int locals = 0;
        struct bau_desc *bau_desc;
        struct cpumask *flush_mask;
        struct ptc_stats *stat;
        struct bau_control *bcp;
        struct bau_control *tbcp;

        /* kernel was booted 'nobau' */
        if (nobau)
                return cpumask;

        bcp = &per_cpu(bau_control, cpu);
        stat = &per_cpu(ptcstats, cpu);

        /* bau was disabled due to slow response */
        if (bcp->baudisabled) {
                /* the cpu that disabled it must re-enable it */
                if (bcp->set_bau_off) {
                        if (get_cycles() >= bcp->set_bau_on_time) {
                                stat->s_bau_reenabled++;
                                baudisabled = 0;
                                for_each_present_cpu(tcpu) {
                                        tbcp = &per_cpu(bau_control, tcpu);
                                        tbcp->baudisabled = 0;
                                        tbcp->period_requests = 0;
                                        tbcp->period_time = 0;
                                }
                        }
                }
                return cpumask;
        }

        /*
         * Each sending cpu has a per-cpu mask which it fills from the caller's
         * cpu mask.  Only remote cpus are converted to uvhubs and copied.
         */
        flush_mask = (struct cpumask *)per_cpu(uv_flush_tlb_mask, cpu);
        /*
         * copy cpumask to flush_mask, removing current cpu
         * (current cpu should already have been flushed by the caller and
         *  should never be returned if we return flush_mask)
         */
        cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));
        if (cpu_isset(cpu, *cpumask))
                locals++;  /* current cpu was targeted */

        bau_desc = bcp->descriptor_base;
        bau_desc += UV_ITEMS_PER_DESCRIPTOR * bcp->uvhub_cpu;

        bau_uvhubs_clear(&bau_desc->distribution, UV_DISTRIBUTION_SIZE);
        remotes = 0;
        for_each_cpu(tcpu, flush_mask) {
                uvhub = uv_cpu_to_blade_id(tcpu);
                if (uvhub == bcp->uvhub) {
                        locals++;
                        continue;
                }
                bau_uvhub_set(uvhub, &bau_desc->distribution);
                remotes++;
        }
        if (remotes == 0) {
                /*
                 * No off_hub flushing; return status for local hub.
                 * Return the caller's mask if all were local (the current
                 * cpu may be in that mask).
                 */
                if (locals)
                        return cpumask;
                else
                        return NULL;
        }
        stat->s_requestor++;
        stat->s_ntargcpu += remotes;
        remotes = bau_uvhub_weight(&bau_desc->distribution);
        stat->s_ntarguvhub += remotes;
        if (remotes >= 16)
                stat->s_ntarguvhub16++;
        else if (remotes >= 8)
                stat->s_ntarguvhub8++;
        else if (remotes >= 4)
                stat->s_ntarguvhub4++;
        else if (remotes >= 2)
                stat->s_ntarguvhub2++;
        else
                stat->s_ntarguvhub1++;

        bau_desc->payload.address = va;
        bau_desc->payload.sending_cpu = cpu;

        /*
         * uv_flush_send_and_wait returns null if all cpu's were messaged, or
         * the adjusted flush_mask if any cpu's were not messaged.
         */
        return uv_flush_send_and_wait(bau_desc, flush_mask, bcp);
}

/*
 * The BAU message interrupt comes here. (registered by set_intr_gate)
 * See entry_64.S
 *
 * We received a broadcast assist message.
 *
 * Interrupts are disabled; this interrupt could represent
 * the receipt of several messages.
 *
 * All cores/threads on this hub get this interrupt.
 * The last one to see it does the software ack.
 * (the resource will not be freed until noninterruptable cpus see this
 *  interrupt; hardware may timeout the s/w ack and reply ERROR)
 */
void uv_bau_message_interrupt(struct pt_regs *regs)
{
        int count = 0;
        cycles_t time_start;
        struct bau_payload_queue_entry *msg;
        struct bau_control *bcp;
        struct ptc_stats *stat;
        struct msg_desc msgdesc;

        time_start = get_cycles();
        bcp = &per_cpu(bau_control, smp_processor_id());
        stat = &per_cpu(ptcstats, smp_processor_id());
        msgdesc.va_queue_first = bcp->va_queue_first;
        msgdesc.va_queue_last = bcp->va_queue_last;
        msg = bcp->bau_msg_head;
        while (msg->sw_ack_vector) {
                count++;
                msgdesc.msg_slot = msg - msgdesc.va_queue_first;
                msgdesc.sw_ack_slot = ffs(msg->sw_ack_vector) - 1;
                msgdesc.msg = msg;
                uv_bau_process_message(&msgdesc, bcp);
                msg++;
                if (msg > msgdesc.va_queue_last)
                        msg = msgdesc.va_queue_first;
                bcp->bau_msg_head = msg;
        }
        stat->d_time += (get_cycles() - time_start);
        if (!count)
                stat->d_nomsg++;
        else if (count > 1)
                stat->d_multmsg++;
        ack_APIC_irq();
}

/*
 * uv_enable_timeouts
 *
 * Each target uvhub (i.e. a uvhub that has no cpu's) needs to have
 * shootdown message timeouts enabled.  The timeout does not cause
 * an interrupt, but causes an error message to be returned to
 * the sender.
 */
static void uv_enable_timeouts(void)
{
        int uvhub;
        int nuvhubs;
        int pnode;
        unsigned long mmr_image;

        nuvhubs = uv_num_possible_blades();

        for (uvhub = 0; uvhub < nuvhubs; uvhub++) {
                if (!uv_blade_nr_possible_cpus(uvhub))
                        continue;

                pnode = uv_blade_to_pnode(uvhub);
                mmr_image =
                    uv_read_global_mmr64(pnode, UVH_LB_BAU_MISC_CONTROL);
                /*
                 * Set the timeout period and then lock it in, in three
                 * steps; captures and locks in the period.
                 *
                 * To program the period, the SOFT_ACK_MODE must be off.
                 */
                mmr_image &= ~((unsigned long)1 <<
                    UVH_LB_BAU_MISC_CONTROL_ENABLE_INTD_SOFT_ACK_MODE_SHFT);
                uv_write_global_mmr64
                    (pnode, UVH_LB_BAU_MISC_CONTROL, mmr_image);
                /*
                 * Set the 4-bit period.
                 */
                mmr_image &= ~((unsigned long)0xf <<
                     UVH_LB_BAU_MISC_CONTROL_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHFT);
                mmr_image |= (UV_INTD_SOFT_ACK_TIMEOUT_PERIOD <<
                     UVH_LB_BAU_MISC_CONTROL_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHFT);
                uv_write_global_mmr64
                    (pnode, UVH_LB_BAU_MISC_CONTROL, mmr_image);
                /*
                 * Subsequent reversals of the timebase bit (3) cause an
                 * immediate timeout of one or all INTD resources as
                 * indicated in bits 2:0 (7 causes all of them to timeout).
                 */
                mmr_image |= ((unsigned long)1 <<
                    UVH_LB_BAU_MISC_CONTROL_ENABLE_INTD_SOFT_ACK_MODE_SHFT);
                uv_write_global_mmr64
                    (pnode, UVH_LB_BAU_MISC_CONTROL, mmr_image);
        }
}

static void *uv_ptc_seq_start(struct seq_file *file, loff_t *offset)
{
        if (*offset < num_possible_cpus())
                return offset;
        return NULL;
}

static void *uv_ptc_seq_next(struct seq_file *file, void *data, loff_t *offset)
{
        (*offset)++;
        if (*offset < num_possible_cpus())
                return offset;
        return NULL;
}

static void uv_ptc_seq_stop(struct seq_file *file, void *data)
{
}

static inline unsigned long long
microsec_2_cycles(unsigned long microsec)
{
        unsigned long ns;
        unsigned long long cyc;

        ns = microsec * 1000;
        cyc = (ns << CYC2NS_SCALE_FACTOR)/(per_cpu(cyc2ns, smp_processor_id()));
        return cyc;
}

/*
 * Display the statistics thru /proc.
 * 'data' points to the cpu number
 */
static int uv_ptc_seq_show(struct seq_file *file, void *data)
{
        struct ptc_stats *stat;
        int cpu;

        cpu = *(loff_t *)data;

        if (!cpu) {
                seq_printf(file,
                        "# cpu sent stime numuvhubs numuvhubs16 numuvhubs8 ");
                seq_printf(file,
                        "numuvhubs4 numuvhubs2 numuvhubs1 numcpus dto ");
                seq_printf(file,
                        "retries rok resetp resett giveup sto bz throt ");
                seq_printf(file,
                        "sw_ack recv rtime all ");
                seq_printf(file,
                        "one mult none retry canc nocan reset rcan ");
                seq_printf(file,
                        "disable enable\n");
        }
        if (cpu < num_possible_cpus() && cpu_online(cpu)) {
                stat = &per_cpu(ptcstats, cpu);
                /* source side statistics */
                seq_printf(file,
                        "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",
                           cpu, stat->s_requestor, cycles_2_us(stat->s_time),
                           stat->s_ntarguvhub, stat->s_ntarguvhub16,
                           stat->s_ntarguvhub8, stat->s_ntarguvhub4,
                           stat->s_ntarguvhub2, stat->s_ntarguvhub1,
                           stat->s_ntargcpu, stat->s_dtimeout);
                seq_printf(file, "%ld %ld %ld %ld %ld %ld %ld %ld ",
                           stat->s_retry_messages, stat->s_retriesok,
                           stat->s_resets_plug, stat->s_resets_timeout,
                           stat->s_giveup, stat->s_stimeout,
                           stat->s_busy, stat->s_throttles);

                /* destination side statistics */
                seq_printf(file,
                           "%lx %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",
                           uv_read_global_mmr64(uv_cpu_to_pnode(cpu),
                                        UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE),
                           stat->d_requestee, cycles_2_us(stat->d_time),
                           stat->d_alltlb, stat->d_onetlb, stat->d_multmsg,
                           stat->d_nomsg, stat->d_retries, stat->d_canceled,
                           stat->d_nocanceled, stat->d_resets,
                           stat->d_rcanceled);
                seq_printf(file, "%ld %ld\n",
                        stat->s_bau_disabled, stat->s_bau_reenabled);
        }

        return 0;
}

/*
 * Display the tunables thru debugfs
 */
static ssize_t tunables_read(struct file *file, char __user *userbuf,
                                                size_t count, loff_t *ppos)
{
        char buf[300];
        int ret;

        ret = snprintf(buf, 300, "%s %s %s\n%d %d %d %d %d %d %d %d %d\n",
                "max_bau_concurrent plugged_delay plugsb4reset",
                "timeoutsb4reset ipi_reset_limit complete_threshold",
                "congested_response_us congested_reps congested_period",
                max_bau_concurrent, plugged_delay, plugsb4reset,
                timeoutsb4reset, ipi_reset_limit, complete_threshold,
                congested_response_us, congested_reps, congested_period);

        return simple_read_from_buffer(userbuf, count, ppos, buf, ret);
}

/*
 * -1: resetf the statistics
 *  0: display meaning of the statistics
 */
static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
                                 size_t count, loff_t *data)
{
        int cpu;
        long input_arg;
        char optstr[64];
        struct ptc_stats *stat;

        if (count == 0 || count > sizeof(optstr))
                return -EINVAL;
        if (copy_from_user(optstr, user, count))
                return -EFAULT;
        optstr[count - 1] = '\0';
        if (strict_strtol(optstr, 10, &input_arg) < 0) {
                printk(KERN_DEBUG "%s is invalid\n", optstr);
                return -EINVAL;
        }

        if (input_arg == 0) {
                printk(KERN_DEBUG "# cpu:      cpu number\n");
                printk(KERN_DEBUG "Sender statistics:\n");
                printk(KERN_DEBUG
                "sent:     number of shootdown messages sent\n");
                printk(KERN_DEBUG
                "stime:    time spent sending messages\n");
                printk(KERN_DEBUG
                "numuvhubs: number of hubs targeted with shootdown\n");
                printk(KERN_DEBUG
                "numuvhubs16: number times 16 or more hubs targeted\n");
                printk(KERN_DEBUG
                "numuvhubs8: number times 8 or more hubs targeted\n");
                printk(KERN_DEBUG
                "numuvhubs4: number times 4 or more hubs targeted\n");
                printk(KERN_DEBUG
                "numuvhubs2: number times 2 or more hubs targeted\n");
                printk(KERN_DEBUG
                "numuvhubs1: number times 1 hub targeted\n");
                printk(KERN_DEBUG
                "numcpus:  number of cpus targeted with shootdown\n");
                printk(KERN_DEBUG
                "dto:      number of destination timeouts\n");
                printk(KERN_DEBUG
                "retries:  destination timeout retries sent\n");
                printk(KERN_DEBUG
                "rok:   :  destination timeouts successfully retried\n");
                printk(KERN_DEBUG
                "resetp:   ipi-style resource resets for plugs\n");
                printk(KERN_DEBUG
                "resett:   ipi-style resource resets for timeouts\n");
                printk(KERN_DEBUG
                "giveup:   fall-backs to ipi-style shootdowns\n");
                printk(KERN_DEBUG
                "sto:      number of source timeouts\n");
                printk(KERN_DEBUG
                "bz:       number of stay-busy's\n");
                printk(KERN_DEBUG
                "throt:    number times spun in throttle\n");
                printk(KERN_DEBUG "Destination side statistics:\n");
                printk(KERN_DEBUG
                "sw_ack:   image of UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE\n");
                printk(KERN_DEBUG
                "recv:     shootdown messages received\n");
                printk(KERN_DEBUG
                "rtime:    time spent processing messages\n");
                printk(KERN_DEBUG
                "all:      shootdown all-tlb messages\n");
                printk(KERN_DEBUG
                "one:      shootdown one-tlb messages\n");
                printk(KERN_DEBUG
                "mult:     interrupts that found multiple messages\n");
                printk(KERN_DEBUG
                "none:     interrupts that found no messages\n");
                printk(KERN_DEBUG
                "retry:    number of retry messages processed\n");
                printk(KERN_DEBUG
                "canc:     number messages canceled by retries\n");
                printk(KERN_DEBUG
                "nocan:    number retries that found nothing to cancel\n");
                printk(KERN_DEBUG
                "reset:    number of ipi-style reset requests processed\n");
                printk(KERN_DEBUG
                "rcan:     number messages canceled by reset requests\n");
                printk(KERN_DEBUG
                "disable:  number times use of the BAU was disabled\n");
                printk(KERN_DEBUG
                "enable:   number times use of the BAU was re-enabled\n");
        } else if (input_arg == -1) {
                for_each_present_cpu(cpu) {
                        stat = &per_cpu(ptcstats, cpu);
                        memset(stat, 0, sizeof(struct ptc_stats));
                }
        }

        return count;
}

static int local_atoi(const char *name)
{
        int val = 0;

        for (;; name++) {
                switch (*name) {
                case '0' ... '9':
                        val = 10*val+(*name-'0');
                        break;
                default:
                        return val;
                }
        }
}

/*
 * set the tunables
 * 0 values reset them to defaults
 */
static ssize_t tunables_write(struct file *file, const char __user *user,
                                 size_t count, loff_t *data)
{
        int cpu;
        int cnt = 0;
        int val;
        char *p;
        char *q;
        char instr[64];
        struct bau_control *bcp;

        if (count == 0 || count > sizeof(instr)-1)
                return -EINVAL;
        if (copy_from_user(instr, user, count))
                return -EFAULT;

        instr[count] = '\0';
        /* count the fields */
        p = instr + strspn(instr, WHITESPACE);
        q = p;
        for (; *p; p = q + strspn(q, WHITESPACE)) {
                q = p + strcspn(p, WHITESPACE);
                cnt++;
                if (q == p)
                        break;
        }
        if (cnt != 9) {
                printk(KERN_INFO "bau tunable error: should be 9 numbers\n");
                return -EINVAL;
        }

        p = instr + strspn(instr, WHITESPACE);
        q = p;
        for (cnt = 0; *p; p = q + strspn(q, WHITESPACE), cnt++) {
                q = p + strcspn(p, WHITESPACE);
                val = local_atoi(p);
                switch (cnt) {
                case 0:
                        if (val == 0) {
                                max_bau_concurrent = MAX_BAU_CONCURRENT;
                                max_bau_concurrent_constant =
                                                        MAX_BAU_CONCURRENT;
                                continue;
                        }
                        bcp = &per_cpu(bau_control, smp_processor_id());
                        if (val < 1 || val > bcp->cpus_in_uvhub) {
                                printk(KERN_DEBUG
                                "Error: BAU max concurrent %d is invalid\n",
                                val);
                                return -EINVAL;
                        }
                        max_bau_concurrent = val;
                        max_bau_concurrent_constant = val;
                        continue;
                case 1:
                        if (val == 0)
                                plugged_delay = PLUGGED_DELAY;
                        else
                                plugged_delay = val;
                        continue;
                case 2:
                        if (val == 0)
                                plugsb4reset = PLUGSB4RESET;
                        else
                                plugsb4reset = val;
                        continue;
                case 3:
                        if (val == 0)
                                timeoutsb4reset = TIMEOUTSB4RESET;
                        else
                                timeoutsb4reset = val;
                        continue;
                case 4:
                        if (val == 0)
                                ipi_reset_limit = IPI_RESET_LIMIT;
                        else
                                ipi_reset_limit = val;
                        continue;
                case 5:
                        if (val == 0)
                                complete_threshold = COMPLETE_THRESHOLD;
                        else
                                complete_threshold = val;
                        continue;
                case 6:
                        if (val == 0)
                                congested_response_us = CONGESTED_RESPONSE_US;
                        else
                                congested_response_us = val;
                        continue;
                case 7:
                        if (val == 0)
                                congested_reps = CONGESTED_REPS;
                        else
                                congested_reps = val;
                        continue;
                case 8:
                        if (val == 0)
                                congested_period = CONGESTED_PERIOD;
                        else
                                congested_period = val;
                        continue;
                }
                if (q == p)
                        break;
        }
        for_each_present_cpu(cpu) {
                bcp = &per_cpu(bau_control, cpu);
                bcp->max_bau_concurrent = max_bau_concurrent;
                bcp->max_bau_concurrent_constant = max_bau_concurrent;
                bcp->plugged_delay = plugged_delay;
                bcp->plugsb4reset = plugsb4reset;
                bcp->timeoutsb4reset = timeoutsb4reset;
                bcp->ipi_reset_limit = ipi_reset_limit;
                bcp->complete_threshold = complete_threshold;
                bcp->congested_response_us = congested_response_us;
                bcp->congested_reps = congested_reps;
                bcp->congested_period = congested_period;
        }
        return count;
}

static const struct seq_operations uv_ptc_seq_ops = {
        .start          = uv_ptc_seq_start,
        .next           = uv_ptc_seq_next,
        .stop           = uv_ptc_seq_stop,
        .show           = uv_ptc_seq_show
};

static int uv_ptc_proc_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &uv_ptc_seq_ops);
}

static int tunables_open(struct inode *inode, struct file *file)
{
        return 0;
}

static const struct file_operations proc_uv_ptc_operations = {
        .open           = uv_ptc_proc_open,
        .read           = seq_read,
        .write          = uv_ptc_proc_write,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

static const struct file_operations tunables_fops = {
        .open           = tunables_open,
        .read           = tunables_read,
        .write          = tunables_write,
};

static int __init uv_ptc_init(void)
{
        struct proc_dir_entry *proc_uv_ptc;

        if (!is_uv_system())
                return 0;

        proc_uv_ptc = proc_create(UV_PTC_BASENAME, 0444, NULL,
                                  &proc_uv_ptc_operations);
        if (!proc_uv_ptc) {
                printk(KERN_ERR "unable to create %s proc entry\n",
                       UV_PTC_BASENAME);
                return -EINVAL;
        }

        tunables_dir = debugfs_create_dir(UV_BAU_TUNABLES_DIR, NULL);
        if (!tunables_dir) {
                printk(KERN_ERR "unable to create debugfs directory %s\n",
                       UV_BAU_TUNABLES_DIR);
                return -EINVAL;
        }
        tunables_file = debugfs_create_file(UV_BAU_TUNABLES_FILE, 0600,
                        tunables_dir, NULL, &tunables_fops);
        if (!tunables_file) {
                printk(KERN_ERR "unable to create debugfs file %s\n",
                       UV_BAU_TUNABLES_FILE);
                return -EINVAL;
        }
        return 0;
}

/*
 * initialize the sending side's sending buffers
 */
static void
uv_activation_descriptor_init(int node, int pnode)
{
        int i;
        int cpu;
        unsigned long pa;
        unsigned long m;
        unsigned long n;
        struct bau_desc *bau_desc;
        struct bau_desc *bd2;
        struct bau_control *bcp;

        /*
         * each bau_desc is 64 bytes; there are 8 (UV_ITEMS_PER_DESCRIPTOR)
         * per cpu; and up to 32 (UV_ADP_SIZE) cpu's per uvhub
         */
        bau_desc = (struct bau_desc *)kmalloc_node(sizeof(struct bau_desc)*
                UV_ADP_SIZE*UV_ITEMS_PER_DESCRIPTOR, GFP_KERNEL, node);
        BUG_ON(!bau_desc);

        pa = uv_gpa(bau_desc); /* need the real nasid*/
        n = pa >> uv_nshift;
        m = pa & uv_mmask;

        uv_write_global_mmr64(pnode, UVH_LB_BAU_SB_DESCRIPTOR_BASE,
                              (n << UV_DESC_BASE_PNODE_SHIFT | m));

        /*
         * initializing all 8 (UV_ITEMS_PER_DESCRIPTOR) descriptors for each
         * cpu even though we only use the first one; one descriptor can
         * describe a broadcast to 256 uv hubs.
         */
        for (i = 0, bd2 = bau_desc; i < (UV_ADP_SIZE*UV_ITEMS_PER_DESCRIPTOR);
                i++, bd2++) {
                memset(bd2, 0, sizeof(struct bau_desc));
                bd2->header.sw_ack_flag = 1;
                /*
                 * base_dest_nodeid is the nasid (pnode<<1) of the first uvhub
                 * in the partition. The bit map will indicate uvhub numbers,
                 * which are 0-N in a partition. Pnodes are unique system-wide.
                 */
                bd2->header.base_dest_nodeid = uv_partition_base_pnode << 1;
                bd2->header.dest_subnodeid = 0x10; /* the LB */
                bd2->header.command = UV_NET_ENDPOINT_INTD;
                bd2->header.int_both = 1;
                /*
                 * all others need to be set to zero:
                 *   fairness chaining multilevel count replied_to
                 */
        }
        for_each_present_cpu(cpu) {
                if (pnode != uv_blade_to_pnode(uv_cpu_to_blade_id(cpu)))
                        continue;
                bcp = &per_cpu(bau_control, cpu);
                bcp->descriptor_base = bau_desc;
        }
}

/*
 * initialize the destination side's receiving buffers
 * entered for each uvhub in the partition
 * - node is first node (kernel memory notion) on the uvhub
 * - pnode is the uvhub's physical identifier
 */
static void
uv_payload_queue_init(int node, int pnode)
{
        int pn;
        int cpu;
        char *cp;
        unsigned long pa;
        struct bau_payload_queue_entry *pqp;
        struct bau_payload_queue_entry *pqp_malloc;
        struct bau_control *bcp;

        pqp = (struct bau_payload_queue_entry *) kmalloc_node(
                (DEST_Q_SIZE + 1) * sizeof(struct bau_payload_queue_entry),
                GFP_KERNEL, node);
        BUG_ON(!pqp);
        pqp_malloc = pqp;

        cp = (char *)pqp + 31;
        pqp = (struct bau_payload_queue_entry *)(((unsigned long)cp >> 5) << 5);

        for_each_present_cpu(cpu) {
                if (pnode != uv_cpu_to_pnode(cpu))
                        continue;
                /* for every cpu on this pnode: */
                bcp = &per_cpu(bau_control, cpu);
                bcp->va_queue_first = pqp;
                bcp->bau_msg_head = pqp;
                bcp->va_queue_last = pqp + (DEST_Q_SIZE - 1);
        }
        /*
         * need the pnode of where the memory was really allocated
         */
        pa = uv_gpa(pqp);
        pn = pa >> uv_nshift;
        uv_write_global_mmr64(pnode,
                              UVH_LB_BAU_INTD_PAYLOAD_QUEUE_FIRST,
                              ((unsigned long)pn << UV_PAYLOADQ_PNODE_SHIFT) |
                              uv_physnodeaddr(pqp));
        uv_write_global_mmr64(pnode, UVH_LB_BAU_INTD_PAYLOAD_QUEUE_TAIL,
                              uv_physnodeaddr(pqp));
        uv_write_global_mmr64(pnode, UVH_LB_BAU_INTD_PAYLOAD_QUEUE_LAST,
                              (unsigned long)
                              uv_physnodeaddr(pqp + (DEST_Q_SIZE - 1)));
        /* in effect, all msg_type's are set to MSG_NOOP */
        memset(pqp, 0, sizeof(struct bau_payload_queue_entry) * DEST_Q_SIZE);
}

/*
 * Initialization of each UV hub's structures
 */
static void __init uv_init_uvhub(int uvhub, int vector)
{
        int node;
        int pnode;
        unsigned long apicid;

        node = uvhub_to_first_node(uvhub);
        pnode = uv_blade_to_pnode(uvhub);
        uv_activation_descriptor_init(node, pnode);
        uv_payload_queue_init(node, pnode);
        /*
         * the below initialization can't be in firmware because the
         * messaging IRQ will be determined by the OS
         */
        apicid = uvhub_to_first_apicid(uvhub);
        uv_write_global_mmr64(pnode, UVH_BAU_DATA_CONFIG,
                                      ((apicid << 32) | vector));
}

/*
 * We will set BAU_MISC_CONTROL with a timeout period.
 * But the BIOS has set UVH_AGING_PRESCALE_SEL and UVH_TRANSACTION_TIMEOUT.
 * So the destination timeout period has be be calculated from them.
 */
static int
calculate_destination_timeout(void)
{
        unsigned long mmr_image;
        int mult1;
        int mult2;
        int index;
        int base;
        int ret;
        unsigned long ts_ns;

        mult1 = UV_INTD_SOFT_ACK_TIMEOUT_PERIOD & BAU_MISC_CONTROL_MULT_MASK;
        mmr_image = uv_read_local_mmr(UVH_AGING_PRESCALE_SEL);
        index = (mmr_image >> BAU_URGENCY_7_SHIFT) & BAU_URGENCY_7_MASK;
        mmr_image = uv_read_local_mmr(UVH_TRANSACTION_TIMEOUT);
        mult2 = (mmr_image >> BAU_TRANS_SHIFT) & BAU_TRANS_MASK;
        base = timeout_base_ns[index];
        ts_ns = base * mult1 * mult2;
        ret = ts_ns / 1000;
        return ret;
}

/*
 * initialize the bau_control structure for each cpu
 */
static void uv_init_per_cpu(int nuvhubs)
{
        int i, j, k;
        int cpu;
        int pnode;
        int uvhub;
        short socket = 0;
        struct bau_control *bcp;
        struct uvhub_desc *bdp;
        struct socket_desc *sdp;
        struct bau_control *hmaster = NULL;
        struct bau_control *smaster = NULL;
        struct socket_desc {
                short num_cpus;
                short cpu_number[16];
        };
        struct uvhub_desc {
                short num_sockets;
                short num_cpus;
                short uvhub;
                short pnode;
                struct socket_desc socket[2];
        };
        struct uvhub_desc *uvhub_descs;

        timeout_us = calculate_destination_timeout();

        uvhub_descs = (struct uvhub_desc *)
                kmalloc(nuvhubs * sizeof(struct uvhub_desc), GFP_KERNEL);
        memset(uvhub_descs, 0, nuvhubs * sizeof(struct uvhub_desc));
        for_each_present_cpu(cpu) {
                bcp = &per_cpu(bau_control, cpu);
                memset(bcp, 0, sizeof(struct bau_control));
                spin_lock_init(&bcp->masks_lock);
                pnode = uv_cpu_hub_info(cpu)->pnode;
                uvhub = uv_cpu_hub_info(cpu)->numa_blade_id;
                bdp = &uvhub_descs[uvhub];
                bdp->num_cpus++;
                bdp->uvhub = uvhub;
                bdp->pnode = pnode;
                /* kludge: assume uv_hub.h is constant */
                socket = (cpu_physical_id(cpu)>>5)&1;
                if (socket >= bdp->num_sockets)
                        bdp->num_sockets = socket+1;
                sdp = &bdp->socket[socket];
                sdp->cpu_number[sdp->num_cpus] = cpu;
                sdp->num_cpus++;
        }
        socket = 0;
        for_each_possible_blade(uvhub) {
                bdp = &uvhub_descs[uvhub];
                for (i = 0; i < bdp->num_sockets; i++) {
                        sdp = &bdp->socket[i];
                        for (j = 0; j < sdp->num_cpus; j++) {
                                cpu = sdp->cpu_number[j];
                                bcp = &per_cpu(bau_control, cpu);
                                bcp->cpu = cpu;
                                if (j == 0) {
                                        smaster = bcp;
                                        if (i == 0)
                                                hmaster = bcp;
                                }
                                bcp->cpus_in_uvhub = bdp->num_cpus;
                                bcp->cpus_in_socket = sdp->num_cpus;
                                bcp->socket_master = smaster;
                                bcp->uvhub_master = hmaster;
                                for (k = 0; k < DEST_Q_SIZE; k++)
                                        bcp->socket_acknowledge_count[k] = 0;
                                bcp->uvhub_cpu =
                                  uv_cpu_hub_info(cpu)->blade_processor_id;
                        }
                        socket++;
                }
        }
        kfree(uvhub_descs);
        for_each_present_cpu(cpu) {
                bcp = &per_cpu(bau_control, cpu);
                bcp->baudisabled = 0;
                /* time interval to catch a hardware stay-busy bug */
                bcp->timeout_interval = microsec_2_cycles(2*timeout_us);
                bcp->max_bau_concurrent = max_bau_concurrent;
                bcp->max_bau_concurrent_constant = max_bau_concurrent;
                bcp->plugged_delay = plugged_delay;
                bcp->plugsb4reset = plugsb4reset;
                bcp->timeoutsb4reset = timeoutsb4reset;
                bcp->ipi_reset_limit = ipi_reset_limit;
                bcp->complete_threshold = complete_threshold;
                bcp->congested_response_us = congested_response_us;
                bcp->congested_reps = congested_reps;
                bcp->congested_period = congested_period;
        }
}

/*
 * Initialization of BAU-related structures
 */
static int __init uv_bau_init(void)
{
        int uvhub;
        int pnode;
        int nuvhubs;
        int cur_cpu;
        int vector;
        unsigned long mmr;

        if (!is_uv_system())
                return 0;

        if (nobau)
                return 0;

        for_each_possible_cpu(cur_cpu)
                zalloc_cpumask_var_node(&per_cpu(uv_flush_tlb_mask, cur_cpu),
                                       GFP_KERNEL, cpu_to_node(cur_cpu));

        max_bau_concurrent = MAX_BAU_CONCURRENT;
        uv_nshift = uv_hub_info->m_val;
        uv_mmask = (1UL << uv_hub_info->m_val) - 1;
        nuvhubs = uv_num_possible_blades();
        spin_lock_init(&disable_lock);
        congested_cycles = microsec_2_cycles(congested_response_us);

        uv_init_per_cpu(nuvhubs);

        uv_partition_base_pnode = 0x7fffffff;
        for (uvhub = 0; uvhub < nuvhubs; uvhub++)
                if (uv_blade_nr_possible_cpus(uvhub) &&
                        (uv_blade_to_pnode(uvhub) < uv_partition_base_pnode))
                        uv_partition_base_pnode = uv_blade_to_pnode(uvhub);

        vector = UV_BAU_MESSAGE;
        for_each_possible_blade(uvhub)
                if (uv_blade_nr_possible_cpus(uvhub))
                        uv_init_uvhub(uvhub, vector);

        uv_enable_timeouts();
        alloc_intr_gate(vector, uv_bau_message_intr1);

        for_each_possible_blade(uvhub) {
                pnode = uv_blade_to_pnode(uvhub);
                /* INIT the bau */
                uv_write_global_mmr64(pnode, UVH_LB_BAU_SB_ACTIVATION_CONTROL,
                                      ((unsigned long)1 << 63));
                mmr = 1; /* should be 1 to broadcast to both sockets */
                uv_write_global_mmr64(pnode, UVH_BAU_DATA_BROADCAST, mmr);
        }

        return 0;
}
core_initcall(uv_bau_init);
fs_initcall(uv_ptc_init);