sn_hwperf.c

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/* 
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2004-2006 Silicon Graphics, Inc. All rights reserved.
 *
 * SGI Altix topology and hardware performance monitoring API.
 * Mark Goodwin <[email protected]>. 
 *
 * Creates /proc/sgi_sn/sn_topology (read-only) to export
 * info about Altix nodes, routers, CPUs and NumaLink
 * interconnection/topology.
 *
 * Also creates a dynamic misc device named "sn_hwperf"
 * that supports an ioctl interface to call down into SAL
 * to discover hw objects, topology and to read/write
 * memory mapped registers, e.g. for performance monitoring.
 * The "sn_hwperf" device is registered only after the procfs
 * file is first opened, i.e. only if/when it's needed. 
 *
 * This API is used by SGI Performance Co-Pilot and other
 * tools, see http://oss.sgi.com/projects/pcp
 */

#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/vmalloc.h>
#include <linux/seq_file.h>
#include <linux/miscdevice.h>
#include <linux/utsname.h>
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/smp.h>
#include <linux/mutex.h>

#include <asm/processor.h>
#include <asm/topology.h>
#include <asm/uaccess.h>
#include <asm/sal.h>
#include <asm/sn/io.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/module.h>
#include <asm/sn/geo.h>
#include <asm/sn/sn2/sn_hwperf.h>
#include <asm/sn/addrs.h>

static void *sn_hwperf_salheap = NULL;
static int sn_hwperf_obj_cnt = 0;
static nasid_t sn_hwperf_master_nasid = INVALID_NASID;
static int sn_hwperf_init(void);
static DEFINE_MUTEX(sn_hwperf_init_mutex);

#define cnode_possible(n)   ((n) < num_cnodes)

static int sn_hwperf_enum_objects(int *nobj, struct sn_hwperf_object_info **ret)
{
    int e;
    u64 sz;
    struct sn_hwperf_object_info *objbuf = NULL;

    if ((e = sn_hwperf_init()) < 0) {
        printk(KERN_ERR "sn_hwperf_init failed: err %d\n", e);
        goto out;
    }

    sz = sn_hwperf_obj_cnt * sizeof(struct sn_hwperf_object_info);
    objbuf = vmalloc(sz);
    if (objbuf == NULL) {
        printk("sn_hwperf_enum_objects: vmalloc(%d) failed\n", (int)sz);
        e = -ENOMEM;
        goto out;
    }

    e = ia64_sn_hwperf_op(sn_hwperf_master_nasid, SN_HWPERF_ENUM_OBJECTS,
        0, sz, (u64) objbuf, 0, 0, NULL);
    if (e != SN_HWPERF_OP_OK) {
        e = -EINVAL;
        vfree(objbuf);
    }

out:
    *nobj = sn_hwperf_obj_cnt;
    *ret = objbuf;
    return e;
}

static int sn_hwperf_location_to_bpos(char *location,
    int *rack, int *bay, int *slot, int *slab)
{
    char type;

    /* first scan for an old style geoid string */
    if (sscanf(location, "%03d%c%02d#%d",
        rack, &type, bay, slab) == 4)
        *slot = 0; 
    else /* scan for a new bladed geoid string */
    if (sscanf(location, "%03d%c%02d^%02d#%d",
        rack, &type, bay, slot, slab) != 5)
        return -1; 
    /* success */
    return 0;
}

static int sn_hwperf_geoid_to_cnode(char *location)
{
    int cnode;
    geoid_t geoid;
    moduleid_t module_id;
    int rack, bay, slot, slab;
    int this_rack, this_bay, this_slot, this_slab;

    if (sn_hwperf_location_to_bpos(location, &rack, &bay, &slot, &slab))
        return -1;

    /*
     * FIXME: replace with cleaner for_each_XXX macro which addresses
     * both compute and IO nodes once ACPI3.0 is available.
     */
    for (cnode = 0; cnode < num_cnodes; cnode++) {
        geoid = cnodeid_get_geoid(cnode);
        module_id = geo_module(geoid);
        this_rack = MODULE_GET_RACK(module_id);
        this_bay = MODULE_GET_BPOS(module_id);
        this_slot = geo_slot(geoid);
        this_slab = geo_slab(geoid);
        if (rack == this_rack && bay == this_bay &&
            slot == this_slot && slab == this_slab) {
            break;
        }
    }

    return cnode_possible(cnode) ? cnode : -1;
}

static int sn_hwperf_obj_to_cnode(struct sn_hwperf_object_info * obj)
{
    if (!SN_HWPERF_IS_NODE(obj) && !SN_HWPERF_IS_IONODE(obj))
        BUG();
    if (SN_HWPERF_FOREIGN(obj))
        return -1;
    return sn_hwperf_geoid_to_cnode(obj->location);
}

static int sn_hwperf_generic_ordinal(struct sn_hwperf_object_info *obj,
                struct sn_hwperf_object_info *objs)
{
    int ordinal;
    struct sn_hwperf_object_info *p;

    for (ordinal=0, p=objs; p != obj; p++) {
        if (SN_HWPERF_FOREIGN(p))
            continue;
        if (SN_HWPERF_SAME_OBJTYPE(p, obj))
            ordinal++;
    }

    return ordinal;
}

static const char *slabname_node =  "node"; /* SHub asic */
static const char *slabname_ionode =    "ionode"; /* TIO asic */
static const char *slabname_router =    "router"; /* NL3R or NL4R */
static const char *slabname_other = "other"; /* unknown asic */

static const char *sn_hwperf_get_slabname(struct sn_hwperf_object_info *obj,
            struct sn_hwperf_object_info *objs, int *ordinal)
{
    int isnode;
    const char *slabname = slabname_other;

    if ((isnode = SN_HWPERF_IS_NODE(obj)) || SN_HWPERF_IS_IONODE(obj)) {
            slabname = isnode ? slabname_node : slabname_ionode;
        *ordinal = sn_hwperf_obj_to_cnode(obj);
    }
    else {
        *ordinal = sn_hwperf_generic_ordinal(obj, objs);
        if (SN_HWPERF_IS_ROUTER(obj))
            slabname = slabname_router;
    }

    return slabname;
}

static void print_pci_topology(struct seq_file *s)
{
    char *p;
    size_t sz;
    int e;

    for (sz = PAGE_SIZE; sz < 16 * PAGE_SIZE; sz += PAGE_SIZE) {
        if (!(p = kmalloc(sz, GFP_KERNEL)))
            break;
        e = ia64_sn_ioif_get_pci_topology(__pa(p), sz);
        if (e == SALRET_OK)
            seq_puts(s, p);
        kfree(p);
        if (e == SALRET_OK || e == SALRET_NOT_IMPLEMENTED)
            break;
    }
}

static inline int sn_hwperf_has_cpus(cnodeid_t node)
{
    return node < MAX_NUMNODES && node_online(node) && nr_cpus_node(node);
}

static inline int sn_hwperf_has_mem(cnodeid_t node)
{
    return node < MAX_NUMNODES && node_online(node) && NODE_DATA(node)->node_present_pages;
}

static struct sn_hwperf_object_info *
sn_hwperf_findobj_id(struct sn_hwperf_object_info *objbuf,
    int nobj, int id)
{
    int i;
    struct sn_hwperf_object_info *p = objbuf;

    for (i=0; i < nobj; i++, p++) {
        if (p->id == id)
            return p;
    }

    return NULL;

}

static int sn_hwperf_get_nearest_node_objdata(struct sn_hwperf_object_info *objbuf,
    int nobj, cnodeid_t node, cnodeid_t *near_mem_node, cnodeid_t *near_cpu_node)
{
    int e;
    struct sn_hwperf_object_info *nodeobj = NULL;
    struct sn_hwperf_object_info *op;
    struct sn_hwperf_object_info *dest;
    struct sn_hwperf_object_info *router;
    struct sn_hwperf_port_info ptdata[16];
    int sz, i, j;
    cnodeid_t c;
    int found_mem = 0;
    int found_cpu = 0;

    if (!cnode_possible(node))
        return -EINVAL;

    if (sn_hwperf_has_cpus(node)) {
        if (near_cpu_node)
            *near_cpu_node = node;
        found_cpu++;
    }

    if (sn_hwperf_has_mem(node)) {
        if (near_mem_node)
            *near_mem_node = node;
        found_mem++;
    }

    if (found_cpu && found_mem)
        return 0; /* trivially successful */

    /* find the argument node object */
    for (i=0, op=objbuf; i < nobj; i++, op++) {
        if (!SN_HWPERF_IS_NODE(op) && !SN_HWPERF_IS_IONODE(op))
            continue;
        if (node == sn_hwperf_obj_to_cnode(op)) {
            nodeobj = op;
            break;
        }
    }
    if (!nodeobj) {
        e = -ENOENT;
        goto err;
    }

    /* get it's interconnect topology */
    sz = op->ports * sizeof(struct sn_hwperf_port_info);
    BUG_ON(sz > sizeof(ptdata));
    e = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                  SN_HWPERF_ENUM_PORTS, nodeobj->id, sz,
                  (u64)&ptdata, 0, 0, NULL);
    if (e != SN_HWPERF_OP_OK) {
        e = -EINVAL;
        goto err;
    }

    /* find nearest node with cpus and nearest memory */
    for (router=NULL, j=0; j < op->ports; j++) {
        dest = sn_hwperf_findobj_id(objbuf, nobj, ptdata[j].conn_id);
        if (dest && SN_HWPERF_IS_ROUTER(dest))
            router = dest;
        if (!dest || SN_HWPERF_FOREIGN(dest) ||
            !SN_HWPERF_IS_NODE(dest) || SN_HWPERF_IS_IONODE(dest)) {
            continue;
        }
        c = sn_hwperf_obj_to_cnode(dest);
        if (!found_cpu && sn_hwperf_has_cpus(c)) {
            if (near_cpu_node)
                *near_cpu_node = c;
            found_cpu++;
        }
        if (!found_mem && sn_hwperf_has_mem(c)) {
            if (near_mem_node)
                *near_mem_node = c;
            found_mem++;
        }
    }

    if (router && (!found_cpu || !found_mem)) {
        /* search for a node connected to the same router */
        sz = router->ports * sizeof(struct sn_hwperf_port_info);
        BUG_ON(sz > sizeof(ptdata));
        e = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                      SN_HWPERF_ENUM_PORTS, router->id, sz,
                      (u64)&ptdata, 0, 0, NULL);
        if (e != SN_HWPERF_OP_OK) {
            e = -EINVAL;
            goto err;
        }
        for (j=0; j < router->ports; j++) {
            dest = sn_hwperf_findobj_id(objbuf, nobj,
                ptdata[j].conn_id);
            if (!dest || dest->id == node ||
                SN_HWPERF_FOREIGN(dest) ||
                !SN_HWPERF_IS_NODE(dest) ||
                SN_HWPERF_IS_IONODE(dest)) {
                continue;
            }
            c = sn_hwperf_obj_to_cnode(dest);
            if (!found_cpu && sn_hwperf_has_cpus(c)) {
                if (near_cpu_node)
                    *near_cpu_node = c;
                found_cpu++;
            }
            if (!found_mem && sn_hwperf_has_mem(c)) {
                if (near_mem_node)
                    *near_mem_node = c;
                found_mem++;
            }
            if (found_cpu && found_mem)
                break;
        }
    }

    if (!found_cpu || !found_mem) {
        /* resort to _any_ node with CPUs and memory */
        for (i=0, op=objbuf; i < nobj; i++, op++) {
            if (SN_HWPERF_FOREIGN(op) ||
                SN_HWPERF_IS_IONODE(op) ||
                !SN_HWPERF_IS_NODE(op)) {
                continue;
            }
            c = sn_hwperf_obj_to_cnode(op);
            if (!found_cpu && sn_hwperf_has_cpus(c)) {
                if (near_cpu_node)
                    *near_cpu_node = c;
                found_cpu++;
            }
            if (!found_mem && sn_hwperf_has_mem(c)) {
                if (near_mem_node)
                    *near_mem_node = c;
                found_mem++;
            }
            if (found_cpu && found_mem)
                break;
        }
    }

    if (!found_cpu || !found_mem)
        e = -ENODATA;

err:
    return e;
}


static int sn_topology_show(struct seq_file *s, void *d)
{
    int sz;
    int pt;
    int e = 0;
    int i;
    int j;
    const char *slabname;
    int ordinal;
    char slice;
    struct cpuinfo_ia64 *c;
    struct sn_hwperf_port_info *ptdata;
    struct sn_hwperf_object_info *p;
    struct sn_hwperf_object_info *obj = d;  /* this object */
    struct sn_hwperf_object_info *objs = s->private; /* all objects */
    u8 shubtype;
    u8 system_size;
    u8 sharing_size;
    u8 partid;
    u8 coher;
    u8 nasid_shift;
    u8 region_size;
    u16 nasid_mask;
    int nasid_msb;

    if (obj == objs) {
        seq_printf(s, "# sn_topology version 2\n");
        seq_printf(s, "# objtype ordinal location partition"
            " [attribute value [, ...]]\n");

        if (ia64_sn_get_sn_info(0,
            &shubtype, &nasid_mask, &nasid_shift, &system_size,
            &sharing_size, &partid, &coher, &region_size))
            BUG();
        for (nasid_msb=63; nasid_msb > 0; nasid_msb--) {
            if (((u64)nasid_mask << nasid_shift) & (1ULL << nasid_msb))
                break;
        }
        seq_printf(s, "partition %u %s local "
            "shubtype %s, "
            "nasid_mask 0x%016llx, "
            "nasid_bits %d:%d, "
            "system_size %d, "
            "sharing_size %d, "
            "coherency_domain %d, "
            "region_size %d\n",

            partid, utsname()->nodename,
            shubtype ? "shub2" : "shub1", 
            (u64)nasid_mask << nasid_shift, nasid_msb, nasid_shift,
            system_size, sharing_size, coher, region_size);

        print_pci_topology(s);
    }

    if (SN_HWPERF_FOREIGN(obj)) {
        /* private in another partition: not interesting */
        return 0;
    }

    for (i = 0; i < SN_HWPERF_MAXSTRING && obj->name[i]; i++) {
        if (obj->name[i] == ' ')
            obj->name[i] = '_';
    }

    slabname = sn_hwperf_get_slabname(obj, objs, &ordinal);
    seq_printf(s, "%s %d %s %s asic %s", slabname, ordinal, obj->location,
        obj->sn_hwp_this_part ? "local" : "shared", obj->name);

    if (ordinal < 0 || (!SN_HWPERF_IS_NODE(obj) && !SN_HWPERF_IS_IONODE(obj)))
        seq_putc(s, '\n');
    else {
        cnodeid_t near_mem = -1;
        cnodeid_t near_cpu = -1;

        seq_printf(s, ", nasid 0x%x", cnodeid_to_nasid(ordinal));

        if (sn_hwperf_get_nearest_node_objdata(objs, sn_hwperf_obj_cnt,
            ordinal, &near_mem, &near_cpu) == 0) {
            seq_printf(s, ", near_mem_nodeid %d, near_cpu_nodeid %d",
                near_mem, near_cpu);
        }

        if (!SN_HWPERF_IS_IONODE(obj)) {
            for_each_online_node(i) {
                seq_printf(s, i ? ":%d" : ", dist %d",
                    node_distance(ordinal, i));
            }
        }

        seq_putc(s, '\n');

        /*
         * CPUs on this node, if any
         */
        if (!SN_HWPERF_IS_IONODE(obj)) {
            for_each_cpu_and(i, cpu_online_mask,
                     cpumask_of_node(ordinal)) {
                slice = 'a' + cpuid_to_slice(i);
                c = cpu_data(i);
                seq_printf(s, "cpu %d %s%c local"
                       " freq %luMHz, arch ia64",
                       i, obj->location, slice,
                       c->proc_freq / 1000000);
                for_each_online_cpu(j) {
                    seq_printf(s, j ? ":%d" : ", dist %d",
                           node_distance(
                                cpu_to_node(i),
                                cpu_to_node(j)));
                }
                seq_putc(s, '\n');
            }
        }
    }

    if (obj->ports) {
        /*
         * numalink ports
         */
        sz = obj->ports * sizeof(struct sn_hwperf_port_info);
        if ((ptdata = kmalloc(sz, GFP_KERNEL)) == NULL)
            return -ENOMEM;
        e = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                      SN_HWPERF_ENUM_PORTS, obj->id, sz,
                      (u64) ptdata, 0, 0, NULL);
        if (e != SN_HWPERF_OP_OK)
            return -EINVAL;
        for (ordinal=0, p=objs; p != obj; p++) {
            if (!SN_HWPERF_FOREIGN(p))
                ordinal += p->ports;
        }
        for (pt = 0; pt < obj->ports; pt++) {
            for (p = objs, i = 0; i < sn_hwperf_obj_cnt; i++, p++) {
                if (ptdata[pt].conn_id == p->id) {
                    break;
                }
            }
            seq_printf(s, "numalink %d %s-%d",
                ordinal+pt, obj->location, ptdata[pt].port);

            if (i >= sn_hwperf_obj_cnt) {
                /* no connection */
                seq_puts(s, " local endpoint disconnected"
                        ", protocol unknown\n");
                continue;
            }

            if (obj->sn_hwp_this_part && p->sn_hwp_this_part)
                /* both ends local to this partition */
                seq_puts(s, " local");
            else if (SN_HWPERF_FOREIGN(p))
                /* both ends of the link in foreign partiton */
                seq_puts(s, " foreign");
            else
                /* link straddles a partition */
                seq_puts(s, " shared");

            /*
             * Unlikely, but strictly should query the LLP config
             * registers because an NL4R can be configured to run
             * NL3 protocol, even when not talking to an NL3 router.
             * Ditto for node-node.
             */
            seq_printf(s, " endpoint %s-%d, protocol %s\n",
                p->location, ptdata[pt].conn_port,
                (SN_HWPERF_IS_NL3ROUTER(obj) ||
                SN_HWPERF_IS_NL3ROUTER(p)) ?  "LLP3" : "LLP4");
        }
        kfree(ptdata);
    }

    return 0;
}

static void *sn_topology_start(struct seq_file *s, loff_t * pos)
{
    struct sn_hwperf_object_info *objs = s->private;

    if (*pos < sn_hwperf_obj_cnt)
        return (void *)(objs + *pos);

    return NULL;
}

static void *sn_topology_next(struct seq_file *s, void *v, loff_t * pos)
{
    ++*pos;
    return sn_topology_start(s, pos);
}

static void sn_topology_stop(struct seq_file *m, void *v)
{
    return;
}

/*
 * /proc/sgi_sn/sn_topology, read-only using seq_file
 */
static const struct seq_operations sn_topology_seq_ops = {
    .start = sn_topology_start,
    .next = sn_topology_next,
    .stop = sn_topology_stop,
    .show = sn_topology_show
};

struct sn_hwperf_op_info {
    u64 op;
    struct sn_hwperf_ioctl_args *a;
    void *p;
    int *v0;
    int ret;
};

static void sn_hwperf_call_sal(void *info)
{
    struct sn_hwperf_op_info *op_info = info;
    int r;

    r = ia64_sn_hwperf_op(sn_hwperf_master_nasid, op_info->op,
              op_info->a->arg, op_info->a->sz,
              (u64) op_info->p, 0, 0, op_info->v0);
    op_info->ret = r;
}

static int sn_hwperf_op_cpu(struct sn_hwperf_op_info *op_info)
{
    u32 cpu;
    u32 use_ipi;
    int r = 0;
    cpumask_t save_allowed;
    
    cpu = (op_info->a->arg & SN_HWPERF_ARG_CPU_MASK) >> 32;
    use_ipi = op_info->a->arg & SN_HWPERF_ARG_USE_IPI_MASK;
    op_info->a->arg &= SN_HWPERF_ARG_OBJID_MASK;

    if (cpu != SN_HWPERF_ARG_ANY_CPU) {
        if (cpu >= nr_cpu_ids || !cpu_online(cpu)) {
            r = -EINVAL;
            goto out;
        }
    }

    if (cpu == SN_HWPERF_ARG_ANY_CPU) {
        /* don't care which cpu */
        sn_hwperf_call_sal(op_info);
    } else if (cpu == get_cpu()) {
        /* already on correct cpu */
        sn_hwperf_call_sal(op_info);
        put_cpu();
    } else {
        put_cpu();
        if (use_ipi) {
            /* use an interprocessor interrupt to call SAL */
            smp_call_function_single(cpu, sn_hwperf_call_sal,
                op_info, 1);
        }
        else {
            /* migrate the task before calling SAL */ 
            save_allowed = current->cpus_allowed;
            set_cpus_allowed_ptr(current, cpumask_of(cpu));
            sn_hwperf_call_sal(op_info);
            set_cpus_allowed_ptr(current, &save_allowed);
        }
    }
    r = op_info->ret;

out:
    return r;
}

/* map SAL hwperf error code to system error code */
static int sn_hwperf_map_err(int hwperf_err)
{
    int e;

    switch(hwperf_err) {
    case SN_HWPERF_OP_OK:
        e = 0;
        break;

    case SN_HWPERF_OP_NOMEM:
        e = -ENOMEM;
        break;

    case SN_HWPERF_OP_NO_PERM:
        e = -EPERM;
        break;

    case SN_HWPERF_OP_IO_ERROR:
        e = -EIO;
        break;

    case SN_HWPERF_OP_BUSY:
        e = -EBUSY;
        break;

    case SN_HWPERF_OP_RECONFIGURE:
        e = -EAGAIN;
        break;

    case SN_HWPERF_OP_INVAL:
    default:
        e = -EINVAL;
        break;
    }

    return e;
}

/*
 * ioctl for "sn_hwperf" misc device
 */
static long sn_hwperf_ioctl(struct file *fp, u32 op, unsigned long arg)
{
    struct sn_hwperf_ioctl_args a;
    struct cpuinfo_ia64 *cdata;
    struct sn_hwperf_object_info *objs;
    struct sn_hwperf_object_info *cpuobj;
    struct sn_hwperf_op_info op_info;
    void *p = NULL;
    int nobj;
    char slice;
    int node;
    int r;
    int v0;
    int i;
    int j;

    /* only user requests are allowed here */
    if ((op & SN_HWPERF_OP_MASK) < 10) {
        r = -EINVAL;
        goto error;
    }
    r = copy_from_user(&a, (const void __user *)arg,
        sizeof(struct sn_hwperf_ioctl_args));
    if (r != 0) {
        r = -EFAULT;
        goto error;
    }

    /*
     * Allocate memory to hold a kernel copy of the user buffer. The
     * buffer contents are either copied in or out (or both) of user
     * space depending on the flags encoded in the requested operation.
     */
    if (a.ptr) {
        p = vmalloc(a.sz);
        if (!p) {
            r = -ENOMEM;
            goto error;
        }
    }

    if (op & SN_HWPERF_OP_MEM_COPYIN) {
        r = copy_from_user(p, (const void __user *)a.ptr, a.sz);
        if (r != 0) {
            r = -EFAULT;
            goto error;
        }
    }

    switch (op) {
    case SN_HWPERF_GET_CPU_INFO:
        if (a.sz == sizeof(u64)) {
            /* special case to get size needed */
            *(u64 *) p = (u64) num_online_cpus() *
                sizeof(struct sn_hwperf_object_info);
        } else
        if (a.sz < num_online_cpus() * sizeof(struct sn_hwperf_object_info)) {
            r = -ENOMEM;
            goto error;
        } else
        if ((r = sn_hwperf_enum_objects(&nobj, &objs)) == 0) {
            int cpuobj_index = 0;

            memset(p, 0, a.sz);
            for (i = 0; i < nobj; i++) {
                if (!SN_HWPERF_IS_NODE(objs + i))
                    continue;
                node = sn_hwperf_obj_to_cnode(objs + i);
                for_each_online_cpu(j) {
                    if (node != cpu_to_node(j))
                        continue;
                    cpuobj = (struct sn_hwperf_object_info *) p + cpuobj_index++;
                    slice = 'a' + cpuid_to_slice(j);
                    cdata = cpu_data(j);
                    cpuobj->id = j;
                    snprintf(cpuobj->name,
                         sizeof(cpuobj->name),
                         "CPU %luMHz %s",
                         cdata->proc_freq / 1000000,
                         cdata->vendor);
                    snprintf(cpuobj->location,
                         sizeof(cpuobj->location),
                         "%s%c", objs[i].location,
                         slice);
                }
            }

            vfree(objs);
        }
        break;

    case SN_HWPERF_GET_NODE_NASID:
        if (a.sz != sizeof(u64) ||
           (node = a.arg) < 0 || !cnode_possible(node)) {
            r = -EINVAL;
            goto error;
        }
        *(u64 *)p = (u64)cnodeid_to_nasid(node);
        break;

    case SN_HWPERF_GET_OBJ_NODE:
        i = a.arg;
        if (a.sz != sizeof(u64) || i < 0) {
            r = -EINVAL;
            goto error;
        }
        if ((r = sn_hwperf_enum_objects(&nobj, &objs)) == 0) {
            if (i >= nobj) {
                r = -EINVAL;
                vfree(objs);
                goto error;
            }
            if (objs[i].id != a.arg) {
                for (i = 0; i < nobj; i++) {
                    if (objs[i].id == a.arg)
                        break;
                }
            }
            if (i == nobj) {
                r = -EINVAL;
                vfree(objs);
                goto error;
            }

            if (!SN_HWPERF_IS_NODE(objs + i) &&
                !SN_HWPERF_IS_IONODE(objs + i)) {
                    r = -ENOENT;
                vfree(objs);
                goto error;
            }

            *(u64 *)p = (u64)sn_hwperf_obj_to_cnode(objs + i);
            vfree(objs);
        }
        break;

    case SN_HWPERF_GET_MMRS:
    case SN_HWPERF_SET_MMRS:
    case SN_HWPERF_OBJECT_DISTANCE:
        op_info.p = p;
        op_info.a = &a;
        op_info.v0 = &v0;
        op_info.op = op;
        r = sn_hwperf_op_cpu(&op_info);
        if (r) {
            r = sn_hwperf_map_err(r);
            a.v0 = v0;
            goto error;
        }
        break;

    default:
        /* all other ops are a direct SAL call */
        r = ia64_sn_hwperf_op(sn_hwperf_master_nasid, op,
                  a.arg, a.sz, (u64) p, 0, 0, &v0);
        if (r) {
            r = sn_hwperf_map_err(r);
            goto error;
        }
        a.v0 = v0;
        break;
    }

    if (op & SN_HWPERF_OP_MEM_COPYOUT) {
        r = copy_to_user((void __user *)a.ptr, p, a.sz);
        if (r != 0) {
            r = -EFAULT;
            goto error;
        }
    }

error:
    vfree(p);

    return r;
}

static const struct file_operations sn_hwperf_fops = {
    .unlocked_ioctl = sn_hwperf_ioctl,
    .llseek = noop_llseek,
};

static struct miscdevice sn_hwperf_dev = {
    MISC_DYNAMIC_MINOR,
    "sn_hwperf",
    &sn_hwperf_fops
};

static int sn_hwperf_init(void)
{
    u64 v;
    int salr;
    int e = 0;

    /* single threaded, once-only initialization */
    mutex_lock(&sn_hwperf_init_mutex);

    if (sn_hwperf_salheap) {
        mutex_unlock(&sn_hwperf_init_mutex);
        return e;
    }

    /*
     * The PROM code needs a fixed reference node. For convenience the
     * same node as the console I/O is used.
     */
    sn_hwperf_master_nasid = (nasid_t) ia64_sn_get_console_nasid();

    /*
     * Request the needed size and install the PROM scratch area.
     * The PROM keeps various tracking bits in this memory area.
     */
    salr = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                 (u64) SN_HWPERF_GET_HEAPSIZE, 0,
                 (u64) sizeof(u64), (u64) &v, 0, 0, NULL);
    if (salr != SN_HWPERF_OP_OK) {
        e = -EINVAL;
        goto out;
    }

    if ((sn_hwperf_salheap = vmalloc(v)) == NULL) {
        e = -ENOMEM;
        goto out;
    }
    salr = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                 SN_HWPERF_INSTALL_HEAP, 0, v,
                 (u64) sn_hwperf_salheap, 0, 0, NULL);
    if (salr != SN_HWPERF_OP_OK) {
        e = -EINVAL;
        goto out;
    }

    salr = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                 SN_HWPERF_OBJECT_COUNT, 0,
                 sizeof(u64), (u64) &v, 0, 0, NULL);
    if (salr != SN_HWPERF_OP_OK) {
        e = -EINVAL;
        goto out;
    }
    sn_hwperf_obj_cnt = (int)v;

out:
    if (e < 0 && sn_hwperf_salheap) {
        vfree(sn_hwperf_salheap);
        sn_hwperf_salheap = NULL;
        sn_hwperf_obj_cnt = 0;
    }
    mutex_unlock(&sn_hwperf_init_mutex);
    return e;
}

int sn_topology_open(struct inode *inode, struct file *file)
{
    int e;
    struct seq_file *seq;
    struct sn_hwperf_object_info *objbuf;
    int nobj;

    if ((e = sn_hwperf_enum_objects(&nobj, &objbuf)) == 0) {
        e = seq_open(file, &sn_topology_seq_ops);
        seq = file->private_data;
        seq->private = objbuf;
    }

    return e;
}

int sn_topology_release(struct inode *inode, struct file *file)
{
    struct seq_file *seq = file->private_data;

    vfree(seq->private);
    return seq_release(inode, file);
}

int sn_hwperf_get_nearest_node(cnodeid_t node,
    cnodeid_t *near_mem_node, cnodeid_t *near_cpu_node)
{
    int e;
    int nobj;
    struct sn_hwperf_object_info *objbuf;

    if ((e = sn_hwperf_enum_objects(&nobj, &objbuf)) == 0) {
        e = sn_hwperf_get_nearest_node_objdata(objbuf, nobj,
            node, near_mem_node, near_cpu_node);
        vfree(objbuf);
    }

    return e;
}

static int __devinit sn_hwperf_misc_register_init(void)
{
    int e;

    if (!ia64_platform_is("sn2"))
        return 0;

    sn_hwperf_init();

    /*
     * Register a dynamic misc device for hwperf ioctls. Platforms
     * supporting hotplug will create /dev/sn_hwperf, else user
     * can to look up the minor number in /proc/misc.
     */
    if ((e = misc_register(&sn_hwperf_dev)) != 0) {
        printk(KERN_ERR "sn_hwperf_misc_register_init: failed to "
        "register misc device for \"%s\"\n", sn_hwperf_dev.name);
    }

    return e;
}

device_initcall(sn_hwperf_misc_register_init); /* after misc_init() */
EXPORT_SYMBOL(sn_hwperf_get_nearest_node);