sn_hwperf.c

/* 
 * 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 <markgw@sgi.com>. 
 *
 * 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/vmalloc.h>
#include <linux/seq_file.h>
#include <linux/miscdevice.h>
#include <linux/utsname.h>
#include <linux/cpumask.h>
#include <linux/smp_lock.h>
#include <linux/nodemask.h>
#include <asm/processor.h>
#include <asm/topology.h>
#include <asm/smp.h>
#include <asm/semaphore.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 DECLARE_MUTEX(sn_hwperf_init_mutex);

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);
	if ((objbuf = (struct sn_hwperf_object_info *) vmalloc(sz)) == 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 node_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 (!obj->sn_hwp_this_part)
		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 = (char *)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_online(node) && nr_cpus_node(node);
}

static inline int sn_hwperf_has_mem(cnodeid_t node)
{
	return 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 (!node_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);
	if (sz > sizeof(ptdata))
		BUG();
	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_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 (SN_HWPERF_IS_ROUTER(dest))
			router = dest;
	}

	if (router && (!found_cpu || !found_mem)) {
		/* search for a node connected to the same router */
		sz = router->ports * sizeof(struct sn_hwperf_port_info);
		if (sz > sizeof(ptdata))
			BUG();
		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;
	cpumask_t cpumask;
	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%016lx, "
			"nasid_bits %d:%d, "
			"system_size %d, "
			"sharing_size %d, "
			"coherency_domain %d, "
			"region_size %d\n",

			partid, system_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 (!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
		 */
		cpumask = node_to_cpumask(ordinal);
		for_each_online_cpu(i) {
			if (cpu_isset(i, cpumask)) {
				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 = vmalloc(sz)) == 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 (!obj->sn_hwp_this_part && !p->sn_hwp_this_part)
				/* 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");
		}
		vfree(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 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_CPUS || !cpu_online(cpu)) {
			r = -EINVAL;
			goto out;
		}
	}

	if (cpu == SN_HWPERF_ARG_ANY_CPU || cpu == get_cpu()) {
		/* don't care, or already on correct cpu */
		sn_hwperf_call_sal(op_info);
	}
	else {
		if (use_ipi) {
			/* use an interprocessor interrupt to call SAL */
			smp_call_function_single(cpu, sn_hwperf_call_sal,
				op_info, 1, 1);
		}
		else {
			/* migrate the task before calling SAL */ 
			save_allowed = current->cpus_allowed;
			set_cpus_allowed(current, cpumask_of_cpu(cpu));
			sn_hwperf_call_sal(op_info);
			set_cpus_allowed(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 int
sn_hwperf_ioctl(struct inode *in, struct file *fp, u32 op, u64 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;

	unlock_kernel();

	/* 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) {
			memset(p, 0, a.sz);
			for (i = 0; i < nobj; i++) {
				int cpuobj_index = 0;
				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 || !node_possible(node)) {
			r = -EINVAL;
			goto error;
		}
		*(u64 *)p = (u64)cnodeid_to_nasid(node);
		break;

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

	lock_kernel();
	return r;
}

static struct file_operations sn_hwperf_fops = {
	.ioctl = sn_hwperf_ioctl,
};

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 */
	down(&sn_hwperf_init_mutex);

	if (sn_hwperf_salheap) {
		up(&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;
	}
	up(&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);