/*
 * SGI NMI support routines
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *  Copyright (c) 2009-2013 Silicon Graphics, Inc.  All Rights Reserved.
 *  Copyright (c) Mike Travis
 */

#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/kdb.h>
#include <linux/kexec.h>
#include <linux/kgdb.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/clocksource.h>

#include <asm/apic.h>
#include <asm/current.h>
#include <asm/kdebug.h>
#include <asm/local64.h>
#include <asm/nmi.h>
#include <asm/traps.h>
#include <asm/uv/uv.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/uv_mmrs.h>

/*
 * UV handler for NMI
 *
 * Handle system-wide NMI events generated by the global 'power nmi' command.
 *
 * Basic operation is to field the NMI interrupt on each cpu and wait
 * until all cpus have arrived into the nmi handler.  If some cpus do not
 * make it into the handler, try and force them in with the IPI(NMI) signal.
 *
 * We also have to lessen UV Hub MMR accesses as much as possible as this
 * disrupts the UV Hub's primary mission of directing NumaLink traffic and
 * can cause system problems to occur.
 *
 * To do this we register our primary NMI notifier on the NMI_UNKNOWN
 * chain.  This reduces the number of false NMI calls when the perf
 * tools are running which generate an enormous number of NMIs per
 * second (~4M/s for 1024 cpu threads).  Our secondary NMI handler is
 * very short as it only checks that if it has been "pinged" with the
 * IPI(NMI) signal as mentioned above, and does not read the UV Hub's MMR.
 *
 */

static struct uv_hub_nmi_s **uv_hub_nmi_list;

DEFINE_PER_CPU(struct uv_cpu_nmi_s, uv_cpu_nmi);
EXPORT_PER_CPU_SYMBOL_GPL(uv_cpu_nmi);

static unsigned long nmi_mmr;
static unsigned long nmi_mmr_clear;
static unsigned long nmi_mmr_pending;

static atomic_t uv_in_nmi;
static atomic_t uv_nmi_cpu = ATOMIC_INIT(-1);
static atomic_t uv_nmi_cpus_in_nmi = ATOMIC_INIT(-1);
static atomic_t uv_nmi_slave_continue;
static cpumask_var_t uv_nmi_cpu_mask;

/* Values for uv_nmi_slave_continue */
#define SLAVE_CLEAR     0
#define SLAVE_CONTINUE  1
#define SLAVE_EXIT      2

/*
 * Default is all stack dumps go to the console and buffer.
 * Lower level to send to log buffer only.
 */
static int uv_nmi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
module_param_named(dump_loglevel, uv_nmi_loglevel, int, 0644);

/*
 * The following values show statistics on how perf events are affecting
 * this system.
 */
static int param_get_local64(char *buffer, const struct kernel_param *kp)
{
        return sprintf(buffer, "%lu\n", local64_read((local64_t *)kp->arg));
}

static int param_set_local64(const char *val, const struct kernel_param *kp)
{
        /* clear on any write */
        local64_set((local64_t *)kp->arg, 0);
        return 0;
}

static const struct kernel_param_ops param_ops_local64 = {
        .get = param_get_local64,
        .set = param_set_local64,
};
#define param_check_local64(name, p) __param_check(name, p, local64_t)

static local64_t uv_nmi_count;
module_param_named(nmi_count, uv_nmi_count, local64, 0644);

static local64_t uv_nmi_misses;
module_param_named(nmi_misses, uv_nmi_misses, local64, 0644);

static local64_t uv_nmi_ping_count;
module_param_named(ping_count, uv_nmi_ping_count, local64, 0644);

static local64_t uv_nmi_ping_misses;
module_param_named(ping_misses, uv_nmi_ping_misses, local64, 0644);

/*
 * Following values allow tuning for large systems under heavy loading
 */
static int uv_nmi_initial_delay = 100;
module_param_named(initial_delay, uv_nmi_initial_delay, int, 0644);

static int uv_nmi_slave_delay = 100;
module_param_named(slave_delay, uv_nmi_slave_delay, int, 0644);

static int uv_nmi_loop_delay = 100;
module_param_named(loop_delay, uv_nmi_loop_delay, int, 0644);

static int uv_nmi_trigger_delay = 10000;
module_param_named(trigger_delay, uv_nmi_trigger_delay, int, 0644);

static int uv_nmi_wait_count = 100;
module_param_named(wait_count, uv_nmi_wait_count, int, 0644);

static int uv_nmi_retry_count = 500;
module_param_named(retry_count, uv_nmi_retry_count, int, 0644);

/*
 * Valid NMI Actions:
 *  "dump"      - dump process stack for each cpu
 *  "ips"       - dump IP info for each cpu
 *  "kdump"     - do crash dump
 *  "kdb"       - enter KDB (default)
 *  "kgdb"      - enter KGDB
 */
static char uv_nmi_action[8] = "kdb";
module_param_string(action, uv_nmi_action, sizeof(uv_nmi_action), 0644);

static inline bool uv_nmi_action_is(const char *action)
{
        return (strncmp(uv_nmi_action, action, strlen(action)) == 0);
}

/* Setup which NMI support is present in system */
static void uv_nmi_setup_mmrs(void)
{
        if (uv_read_local_mmr(UVH_NMI_MMRX_SUPPORTED)) {
                uv_write_local_mmr(UVH_NMI_MMRX_REQ,
                                        1UL << UVH_NMI_MMRX_REQ_SHIFT);
                nmi_mmr = UVH_NMI_MMRX;
                nmi_mmr_clear = UVH_NMI_MMRX_CLEAR;
                nmi_mmr_pending = 1UL << UVH_NMI_MMRX_SHIFT;
                pr_info("UV: SMI NMI support: %s\n", UVH_NMI_MMRX_TYPE);
        } else {
                nmi_mmr = UVH_NMI_MMR;
                nmi_mmr_clear = UVH_NMI_MMR_CLEAR;
                nmi_mmr_pending = 1UL << UVH_NMI_MMR_SHIFT;
                pr_info("UV: SMI NMI support: %s\n", UVH_NMI_MMR_TYPE);
        }
}

/* Read NMI MMR and check if NMI flag was set by BMC. */
static inline int uv_nmi_test_mmr(struct uv_hub_nmi_s *hub_nmi)
{
        hub_nmi->nmi_value = uv_read_local_mmr(nmi_mmr);
        atomic_inc(&hub_nmi->read_mmr_count);
        return !!(hub_nmi->nmi_value & nmi_mmr_pending);
}

static inline void uv_local_mmr_clear_nmi(void)
{
        uv_write_local_mmr(nmi_mmr_clear, nmi_mmr_pending);
}

/*
 * If first cpu in on this hub, set hub_nmi "in_nmi" and "owner" values and
 * return true.  If first cpu in on the system, set global "in_nmi" flag.
 */
static int uv_set_in_nmi(int cpu, struct uv_hub_nmi_s *hub_nmi)
{
        int first = atomic_add_unless(&hub_nmi->in_nmi, 1, 1);

        if (first) {
                atomic_set(&hub_nmi->cpu_owner, cpu);
                if (atomic_add_unless(&uv_in_nmi, 1, 1))
                        atomic_set(&uv_nmi_cpu, cpu);

                atomic_inc(&hub_nmi->nmi_count);
        }
        return first;
}

/* Check if this is a system NMI event */
static int uv_check_nmi(struct uv_hub_nmi_s *hub_nmi)
{
        int cpu = smp_processor_id();
        int nmi = 0;

        local64_inc(&uv_nmi_count);
        this_cpu_inc(uv_cpu_nmi.queries);

        do {
                nmi = atomic_read(&hub_nmi->in_nmi);
                if (nmi)
                        break;

                if (raw_spin_trylock(&hub_nmi->nmi_lock)) {

                        /* check hub MMR NMI flag */
                        if (uv_nmi_test_mmr(hub_nmi)) {
                                uv_set_in_nmi(cpu, hub_nmi);
                                nmi = 1;
                                break;
                        }

                        /* MMR NMI flag is clear */
                        raw_spin_unlock(&hub_nmi->nmi_lock);

                } else {
                        /* wait a moment for the hub nmi locker to set flag */
                        cpu_relax();
                        udelay(uv_nmi_slave_delay);

                        /* re-check hub in_nmi flag */
                        nmi = atomic_read(&hub_nmi->in_nmi);
                        if (nmi)
                                break;
                }

                /* check if this BMC missed setting the MMR NMI flag */
                if (!nmi) {
                        nmi = atomic_read(&uv_in_nmi);
                        if (nmi)
                                uv_set_in_nmi(cpu, hub_nmi);
                }

        } while (0);

        if (!nmi)
                local64_inc(&uv_nmi_misses);

        return nmi;
}

/* Need to reset the NMI MMR register, but only once per hub. */
static inline void uv_clear_nmi(int cpu)
{
        struct uv_hub_nmi_s *hub_nmi = uv_hub_nmi;

        if (cpu == atomic_read(&hub_nmi->cpu_owner)) {
                atomic_set(&hub_nmi->cpu_owner, -1);
                atomic_set(&hub_nmi->in_nmi, 0);
                uv_local_mmr_clear_nmi();
                raw_spin_unlock(&hub_nmi->nmi_lock);
        }
}

/* Ping non-responding cpus attemping to force them into the NMI handler */
static void uv_nmi_nr_cpus_ping(void)
{
        int cpu;

        for_each_cpu(cpu, uv_nmi_cpu_mask)
                uv_cpu_nmi_per(cpu).pinging = 1;

        apic->send_IPI_mask(uv_nmi_cpu_mask, APIC_DM_NMI);
}

/* Clean up flags for cpus that ignored both NMI and ping */
static void uv_nmi_cleanup_mask(void)
{
        int cpu;

        for_each_cpu(cpu, uv_nmi_cpu_mask) {
                uv_cpu_nmi_per(cpu).pinging =  0;
                uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_OUT;
                cpumask_clear_cpu(cpu, uv_nmi_cpu_mask);
        }
}

/* Loop waiting as cpus enter nmi handler */
static int uv_nmi_wait_cpus(int first)
{
        int i, j, k, n = num_online_cpus();
        int last_k = 0, waiting = 0;

        if (first) {
                cpumask_copy(uv_nmi_cpu_mask, cpu_online_mask);
                k = 0;
        } else {
                k = n - cpumask_weight(uv_nmi_cpu_mask);
        }

        udelay(uv_nmi_initial_delay);
        for (i = 0; i < uv_nmi_retry_count; i++) {
                int loop_delay = uv_nmi_loop_delay;

                for_each_cpu(j, uv_nmi_cpu_mask) {
                        if (uv_cpu_nmi_per(j).state) {
                                cpumask_clear_cpu(j, uv_nmi_cpu_mask);
                                if (++k >= n)
                                        break;
                        }
                }
                if (k >= n) {           /* all in? */
                        k = n;
                        break;
                }
                if (last_k != k) {      /* abort if no new cpus coming in */
                        last_k = k;
                        waiting = 0;
                } else if (++waiting > uv_nmi_wait_count)
                        break;

                /* extend delay if waiting only for cpu 0 */
                if (waiting && (n - k) == 1 &&
                    cpumask_test_cpu(0, uv_nmi_cpu_mask))
                        loop_delay *= 100;

                udelay(loop_delay);
        }
        atomic_set(&uv_nmi_cpus_in_nmi, k);
        return n - k;
}

/* Wait until all slave cpus have entered UV NMI handler */
static void uv_nmi_wait(int master)
{
        /* indicate this cpu is in */
        this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_IN);

        /* if not the first cpu in (the master), then we are a slave cpu */
        if (!master)
                return;

        do {
                /* wait for all other cpus to gather here */
                if (!uv_nmi_wait_cpus(1))
                        break;

                /* if not all made it in, send IPI NMI to them */
                pr_alert("UV: Sending NMI IPI to %d non-responding CPUs: %*pbl\n",
                         cpumask_weight(uv_nmi_cpu_mask),
                         cpumask_pr_args(uv_nmi_cpu_mask));

                uv_nmi_nr_cpus_ping();

                /* if all cpus are in, then done */
                if (!uv_nmi_wait_cpus(0))
                        break;

                pr_alert("UV: %d CPUs not in NMI loop: %*pbl\n",
                         cpumask_weight(uv_nmi_cpu_mask),
                         cpumask_pr_args(uv_nmi_cpu_mask));
        } while (0);

        pr_alert("UV: %d of %d CPUs in NMI\n",
                atomic_read(&uv_nmi_cpus_in_nmi), num_online_cpus());
}

/* Dump Instruction Pointer header */
static void uv_nmi_dump_cpu_ip_hdr(void)
{
        pr_info("\nUV: %4s %6s %-32s %s   (Note: PID 0 not listed)\n",
                "CPU", "PID", "COMMAND", "IP");
}

/* Dump Instruction Pointer info */
static void uv_nmi_dump_cpu_ip(int cpu, struct pt_regs *regs)
{
        pr_info("UV: %4d %6d %-32.32s ", cpu, current->pid, current->comm);
        printk_address(regs->ip);
}

/*
 * Dump this CPU's state.  If action was set to "kdump" and the crash_kexec
 * failed, then we provide "dump" as an alternate action.  Action "dump" now
 * also includes the show "ips" (instruction pointers) action whereas the
 * action "ips" only displays instruction pointers for the non-idle CPU's.
 * This is an abbreviated form of the "ps" command.
 */
static void uv_nmi_dump_state_cpu(int cpu, struct pt_regs *regs)
{
        const char *dots = " ................................. ";

        if (cpu == 0)
                uv_nmi_dump_cpu_ip_hdr();

        if (current->pid != 0 || !uv_nmi_action_is("ips"))
                uv_nmi_dump_cpu_ip(cpu, regs);

        if (uv_nmi_action_is("dump")) {
                pr_info("UV:%sNMI process trace for CPU %d\n", dots, cpu);
                show_regs(regs);
        }

        this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_DUMP_DONE);
}

/* Trigger a slave cpu to dump it's state */
static void uv_nmi_trigger_dump(int cpu)
{
        int retry = uv_nmi_trigger_delay;

        if (uv_cpu_nmi_per(cpu).state != UV_NMI_STATE_IN)
                return;

        uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_DUMP;
        do {
                cpu_relax();
                udelay(10);
                if (uv_cpu_nmi_per(cpu).state
                                != UV_NMI_STATE_DUMP)
                        return;
        } while (--retry > 0);

        pr_crit("UV: CPU %d stuck in process dump function\n", cpu);
        uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_DUMP_DONE;
}

/* Wait until all cpus ready to exit */
static void uv_nmi_sync_exit(int master)
{
        atomic_dec(&uv_nmi_cpus_in_nmi);
        if (master) {
                while (atomic_read(&uv_nmi_cpus_in_nmi) > 0)
                        cpu_relax();
                atomic_set(&uv_nmi_slave_continue, SLAVE_CLEAR);
        } else {
                while (atomic_read(&uv_nmi_slave_continue))
                        cpu_relax();
        }
}

/* Walk through cpu list and dump state of each */
static void uv_nmi_dump_state(int cpu, struct pt_regs *regs, int master)
{
        if (master) {
                int tcpu;
                int ignored = 0;
                int saved_console_loglevel = console_loglevel;

                pr_alert("UV: tracing %s for %d CPUs from CPU %d\n",
                        uv_nmi_action_is("ips") ? "IPs" : "processes",
                        atomic_read(&uv_nmi_cpus_in_nmi), cpu);

                console_loglevel = uv_nmi_loglevel;
                atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT);
                for_each_online_cpu(tcpu) {
                        if (cpumask_test_cpu(tcpu, uv_nmi_cpu_mask))
                                ignored++;
                        else if (tcpu == cpu)
                                uv_nmi_dump_state_cpu(tcpu, regs);
                        else
                                uv_nmi_trigger_dump(tcpu);
                }
                if (ignored)
                        pr_alert("UV: %d CPUs ignored NMI\n", ignored);

                console_loglevel = saved_console_loglevel;
                pr_alert("UV: process trace complete\n");
        } else {
                while (!atomic_read(&uv_nmi_slave_continue))
                        cpu_relax();
                while (this_cpu_read(uv_cpu_nmi.state) != UV_NMI_STATE_DUMP)
                        cpu_relax();
                uv_nmi_dump_state_cpu(cpu, regs);
        }
        uv_nmi_sync_exit(master);
}

static void uv_nmi_touch_watchdogs(void)
{
        touch_softlockup_watchdog_sync();
        clocksource_touch_watchdog();
        rcu_cpu_stall_reset();
        touch_nmi_watchdog();
}

static atomic_t uv_nmi_kexec_failed;

#if defined(CONFIG_KEXEC_CORE)
static void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs)
{
        /* Call crash to dump system state */
        if (master) {
                pr_emerg("UV: NMI executing crash_kexec on CPU%d\n", cpu);
                crash_kexec(regs);

                pr_emerg("UV: crash_kexec unexpectedly returned, ");
                atomic_set(&uv_nmi_kexec_failed, 1);
                if (!kexec_crash_image) {
                        pr_cont("crash kernel not loaded\n");
                        return;
                }
                pr_cont("kexec busy, stalling cpus while waiting\n");
        }

        /* If crash exec fails the slaves should return, otherwise stall */
        while (atomic_read(&uv_nmi_kexec_failed) == 0)
                mdelay(10);
}

#else /* !CONFIG_KEXEC_CORE */
static inline void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs)
{
        if (master)
                pr_err("UV: NMI kdump: KEXEC not supported in this kernel\n");
        atomic_set(&uv_nmi_kexec_failed, 1);
}
#endif /* !CONFIG_KEXEC_CORE */

#ifdef CONFIG_KGDB
#ifdef CONFIG_KGDB_KDB
static inline int uv_nmi_kdb_reason(void)
{
        return KDB_REASON_SYSTEM_NMI;
}
#else /* !CONFIG_KGDB_KDB */
static inline int uv_nmi_kdb_reason(void)
{
        /* Insure user is expecting to attach gdb remote */
        if (uv_nmi_action_is("kgdb"))
                return 0;

        pr_err("UV: NMI error: KDB is not enabled in this kernel\n");
        return -1;
}
#endif /* CONFIG_KGDB_KDB */

/*
 * Call KGDB/KDB from NMI handler
 *
 * Note that if both KGDB and KDB are configured, then the action of 'kgdb' or
 * 'kdb' has no affect on which is used.  See the KGDB documention for further
 * information.
 */
static void uv_call_kgdb_kdb(int cpu, struct pt_regs *regs, int master)
{
        if (master) {
                int reason = uv_nmi_kdb_reason();
                int ret;

                if (reason < 0)
                        return;

                /* call KGDB NMI handler as MASTER */
                ret = kgdb_nmicallin(cpu, X86_TRAP_NMI, regs, reason,
                                &uv_nmi_slave_continue);
                if (ret) {
                        pr_alert("KGDB returned error, is kgdboc set?\n");
                        atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT);
                }
        } else {
                /* wait for KGDB signal that it's ready for slaves to enter */
                int sig;

                do {
                        cpu_relax();
                        sig = atomic_read(&uv_nmi_slave_continue);
                } while (!sig);

                /* call KGDB as slave */
                if (sig == SLAVE_CONTINUE)
                        kgdb_nmicallback(cpu, regs);
        }
        uv_nmi_sync_exit(master);
}

#else /* !CONFIG_KGDB */
static inline void uv_call_kgdb_kdb(int cpu, struct pt_regs *regs, int master)
{
        pr_err("UV: NMI error: KGDB is not enabled in this kernel\n");
}
#endif /* !CONFIG_KGDB */

/*
 * UV NMI handler
 */
int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
{
        struct uv_hub_nmi_s *hub_nmi = uv_hub_nmi;
        int cpu = smp_processor_id();
        int master = 0;
        unsigned long flags;

        local_irq_save(flags);

        /* If not a UV System NMI, ignore */
        if (!this_cpu_read(uv_cpu_nmi.pinging) && !uv_check_nmi(hub_nmi)) {
                local_irq_restore(flags);
                return NMI_DONE;
        }

        /* Indicate we are the first CPU into the NMI handler */
        master = (atomic_read(&uv_nmi_cpu) == cpu);

        /* If NMI action is "kdump", then attempt to do it */
        if (uv_nmi_action_is("kdump")) {
                uv_nmi_kdump(cpu, master, regs);

                /* Unexpected return, revert action to "dump" */
                if (master)
                        strncpy(uv_nmi_action, "dump", strlen(uv_nmi_action));
        }

        /* Pause as all cpus enter the NMI handler */
        uv_nmi_wait(master);

        /* Dump state of each cpu */
        if (uv_nmi_action_is("ips") || uv_nmi_action_is("dump"))
                uv_nmi_dump_state(cpu, regs, master);

        /* Call KGDB/KDB if enabled */
        else if (uv_nmi_action_is("kdb") || uv_nmi_action_is("kgdb"))
                uv_call_kgdb_kdb(cpu, regs, master);

        /* Clear per_cpu "in nmi" flag */
        this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_OUT);

        /* Clear MMR NMI flag on each hub */
        uv_clear_nmi(cpu);

        /* Clear global flags */
        if (master) {
                if (cpumask_weight(uv_nmi_cpu_mask))
                        uv_nmi_cleanup_mask();
                atomic_set(&uv_nmi_cpus_in_nmi, -1);
                atomic_set(&uv_nmi_cpu, -1);
                atomic_set(&uv_in_nmi, 0);
                atomic_set(&uv_nmi_kexec_failed, 0);
        }

        uv_nmi_touch_watchdogs();
        local_irq_restore(flags);

        return NMI_HANDLED;
}

/*
 * NMI handler for pulling in CPUs when perf events are grabbing our NMI
 */
static int uv_handle_nmi_ping(unsigned int reason, struct pt_regs *regs)
{
        int ret;

        this_cpu_inc(uv_cpu_nmi.queries);
        if (!this_cpu_read(uv_cpu_nmi.pinging)) {
                local64_inc(&uv_nmi_ping_misses);
                return NMI_DONE;
        }

        this_cpu_inc(uv_cpu_nmi.pings);
        local64_inc(&uv_nmi_ping_count);
        ret = uv_handle_nmi(reason, regs);
        this_cpu_write(uv_cpu_nmi.pinging, 0);
        return ret;
}

static void uv_register_nmi_notifier(void)
{
        if (register_nmi_handler(NMI_UNKNOWN, uv_handle_nmi, 0, "uv"))
                pr_warn("UV: NMI handler failed to register\n");

        if (register_nmi_handler(NMI_LOCAL, uv_handle_nmi_ping, 0, "uvping"))
                pr_warn("UV: PING NMI handler failed to register\n");
}

void uv_nmi_init(void)
{
        unsigned int value;

        /*
         * Unmask NMI on all cpus
         */
        value = apic_read(APIC_LVT1) | APIC_DM_NMI;
        value &= ~APIC_LVT_MASKED;
        apic_write(APIC_LVT1, value);
}

void uv_nmi_setup(void)
{
        int size = sizeof(void *) * (1 << NODES_SHIFT);
        int cpu, nid;

        /* Setup hub nmi info */
        uv_nmi_setup_mmrs();
        uv_hub_nmi_list = kzalloc(size, GFP_KERNEL);
        pr_info("UV: NMI hub list @ 0x%p (%d)\n", uv_hub_nmi_list, size);
        BUG_ON(!uv_hub_nmi_list);
        size = sizeof(struct uv_hub_nmi_s);
        for_each_present_cpu(cpu) {
                nid = cpu_to_node(cpu);
                if (uv_hub_nmi_list[nid] == NULL) {
                        uv_hub_nmi_list[nid] = kzalloc_node(size,
                                                            GFP_KERNEL, nid);
                        BUG_ON(!uv_hub_nmi_list[nid]);
                        raw_spin_lock_init(&(uv_hub_nmi_list[nid]->nmi_lock));
                        atomic_set(&uv_hub_nmi_list[nid]->cpu_owner, -1);
                }
                uv_hub_nmi_per(cpu) = uv_hub_nmi_list[nid];
        }
        BUG_ON(!alloc_cpumask_var(&uv_nmi_cpu_mask, GFP_KERNEL));
        uv_register_nmi_notifier();
}