arch/powerpc/platforms/pseries/dlpar.c - kernel/msm-4.9 - Gitiles

 /*
  * Support for dynamic reconfiguration for PCI, Memory, and CPU
  * Hotplug and Dynamic Logical Partitioning on RPA platforms.
  *
  * Copyright (C) 2009 Nathan Fontenot
  * Copyright (C) 2009 IBM Corporation
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version
  * 2 as published by the Free Software Foundation.
  */

 #include <linux/kernel.h>
 #include <linux/notifier.h>
 #include <linux/spinlock.h>
 #include <linux/cpu.h>
 #include <linux/slab.h>
 #include <linux/of.h>
 #include "offline_states.h"
 #include "pseries.h"

 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/uaccess.h>
 #include <asm/rtas.h>

 struct cc_workarea {
 	u32	drc_index;
 	u32	zero;
 	u32	name_offset;
 	u32	prop_length;
 	u32	prop_offset;
 };

 void dlpar_free_cc_property(struct property *prop)
 {
 	kfree(prop->name);
 	kfree(prop->value);
 	kfree(prop);
 }

 static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
 {
 	struct property *prop;
 	char *name;
 	char *value;

 	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
 	if (!prop)
 		return NULL;

 	name = (char *)ccwa + ccwa->name_offset;
 	prop->name = kstrdup(name, GFP_KERNEL);

 	prop->length = ccwa->prop_length;
 	value = (char *)ccwa + ccwa->prop_offset;
 	prop->value = kmemdup(value, prop->length, GFP_KERNEL);
 	if (!prop->value) {
 		dlpar_free_cc_property(prop);
 		return NULL;
 	}

 	return prop;
 }

 static struct device_node *dlpar_parse_cc_node(struct cc_workarea *ccwa,
 					       const char *path)
 {
 	struct device_node *dn;
 	char *name;

 	/* If parent node path is "/" advance path to NULL terminator to
 	 * prevent double leading slashs in full_name.
 	 */
 	if (!path[1])
 		path++;

 	dn = kzalloc(sizeof(*dn), GFP_KERNEL);
 	if (!dn)
 		return NULL;

 	name = (char *)ccwa + ccwa->name_offset;
 	dn->full_name = kasprintf(GFP_KERNEL, "%s/%s", path, name);
 	if (!dn->full_name) {
 		kfree(dn);
 		return NULL;
 	}

 	of_node_set_flag(dn, OF_DYNAMIC);
 	of_node_init(dn);

 	return dn;
 }

 static void dlpar_free_one_cc_node(struct device_node *dn)
 {
 	struct property *prop;

 	while (dn->properties) {
 		prop = dn->properties;
 		dn->properties = prop->next;
 		dlpar_free_cc_property(prop);
 	}

 	kfree(dn->full_name);
 	kfree(dn);
 }

 void dlpar_free_cc_nodes(struct device_node *dn)
 {
 	if (dn->child)
 		dlpar_free_cc_nodes(dn->child);

 	if (dn->sibling)
 		dlpar_free_cc_nodes(dn->sibling);

 	dlpar_free_one_cc_node(dn);
 }

 #define COMPLETE	0
 #define NEXT_SIBLING    1
 #define NEXT_CHILD      2
 #define NEXT_PROPERTY   3
 #define PREV_PARENT     4
 #define MORE_MEMORY     5
 #define CALL_AGAIN	-2
 #define ERR_CFG_USE     -9003

 struct device_node *dlpar_configure_connector(u32 drc_index,
 					      struct device_node *parent)
 {
 	struct device_node *dn;
 	struct device_node *first_dn = NULL;
 	struct device_node *last_dn = NULL;
 	struct property *property;
 	struct property *last_property = NULL;
 	struct cc_workarea *ccwa;
 	char *data_buf;
 	const char *parent_path = parent->full_name;
 	int cc_token;
 	int rc = -1;

 	cc_token = rtas_token("ibm,configure-connector");
 	if (cc_token == RTAS_UNKNOWN_SERVICE)
 		return NULL;

 	data_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
 	if (!data_buf)
 		return NULL;

 	ccwa = (struct cc_workarea *)&data_buf[0];
 	ccwa->drc_index = drc_index;
 	ccwa->zero = 0;

 	do {
 		/* Since we release the rtas_data_buf lock between configure
 		 * connector calls we want to re-populate the rtas_data_buffer
 		 * with the contents of the previous call.
 		 */
 		spin_lock(&rtas_data_buf_lock);

 		memcpy(rtas_data_buf, data_buf, RTAS_DATA_BUF_SIZE);
 		rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL);
 		memcpy(data_buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);

 		spin_unlock(&rtas_data_buf_lock);

 		switch (rc) {
 		case COMPLETE:
 			break;

 		case NEXT_SIBLING:
 			dn = dlpar_parse_cc_node(ccwa, parent_path);
 			if (!dn)
 				goto cc_error;

 			dn->parent = last_dn->parent;
 			last_dn->sibling = dn;
 			last_dn = dn;
 			break;

 		case NEXT_CHILD:
 			if (first_dn)
 				parent_path = last_dn->full_name;

 			dn = dlpar_parse_cc_node(ccwa, parent_path);
 			if (!dn)
 				goto cc_error;

 			if (!first_dn) {
 				dn->parent = parent;
 				first_dn = dn;
 			} else {
 				dn->parent = last_dn;
 				if (last_dn)
 					last_dn->child = dn;
 			}

 			last_dn = dn;
 			break;

 		case NEXT_PROPERTY:
 			property = dlpar_parse_cc_property(ccwa);
 			if (!property)
 				goto cc_error;

 			if (!last_dn->properties)
 				last_dn->properties = property;
 			else
 				last_property->next = property;

 			last_property = property;
 			break;

 		case PREV_PARENT:
 			last_dn = last_dn->parent;
 			parent_path = last_dn->parent->full_name;
 			break;

 		case CALL_AGAIN:
 			break;

 		case MORE_MEMORY:
 		case ERR_CFG_USE:
 		default:
 			printk(KERN_ERR "Unexpected Error (%d) "
 			       "returned from configure-connector\n", rc);
 			goto cc_error;
 		}
 	} while (rc);

 cc_error:
 	kfree(data_buf);

 	if (rc) {
 		if (first_dn)
 			dlpar_free_cc_nodes(first_dn);

 		return NULL;
 	}

 	return first_dn;
 }

 static struct device_node *derive_parent(const char *path)
 {
 	struct device_node *parent;
 	char *last_slash;

 	last_slash = strrchr(path, '/');
 	if (last_slash == path) {
 		parent = of_find_node_by_path("/");
 	} else {
 		char *parent_path;
 		int parent_path_len = last_slash - path + 1;
 		parent_path = kmalloc(parent_path_len, GFP_KERNEL);
 		if (!parent_path)
 			return NULL;

 		strlcpy(parent_path, path, parent_path_len);
 		parent = of_find_node_by_path(parent_path);
 		kfree(parent_path);
 	}

 	return parent;
 }

 int dlpar_attach_node(struct device_node *dn)
 {
 	int rc;

 	dn->parent = derive_parent(dn->full_name);
 	if (!dn->parent)
 		return -ENOMEM;

 	rc = of_attach_node(dn);
 	if (rc) {
 		printk(KERN_ERR "Failed to add device node %s\n",
 		       dn->full_name);
 		return rc;
 	}

 	of_node_put(dn->parent);
 	return 0;
 }

 int dlpar_detach_node(struct device_node *dn)
 {
 	struct device_node *child;
 	int rc;

 	child = of_get_next_child(dn, NULL);
 	while (child) {
 		dlpar_detach_node(child);
 		child = of_get_next_child(dn, child);
 	}

 	rc = of_detach_node(dn);
 	if (rc)
 		return rc;

 	of_node_put(dn); /* Must decrement the refcount */
 	return 0;
 }

 #define DR_ENTITY_SENSE		9003
 #define DR_ENTITY_PRESENT	1
 #define DR_ENTITY_UNUSABLE	2
 #define ALLOCATION_STATE	9003
 #define ALLOC_UNUSABLE		0
 #define ALLOC_USABLE		1
 #define ISOLATION_STATE		9001
 #define ISOLATE			0
 #define UNISOLATE		1

 int dlpar_acquire_drc(u32 drc_index)
 {
 	int dr_status, rc;

 	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
 		       DR_ENTITY_SENSE, drc_index);
 	if (rc || dr_status != DR_ENTITY_UNUSABLE)
 		return -1;

 	rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_USABLE);
 	if (rc)
 		return rc;

 	rc = rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
 	if (rc) {
 		rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
 		return rc;
 	}

 	return 0;
 }

 int dlpar_release_drc(u32 drc_index)
 {
 	int dr_status, rc;

 	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
 		       DR_ENTITY_SENSE, drc_index);
 	if (rc || dr_status != DR_ENTITY_PRESENT)
 		return -1;

 	rc = rtas_set_indicator(ISOLATION_STATE, drc_index, ISOLATE);
 	if (rc)
 		return rc;

 	rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
 	if (rc) {
 		rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
 		return rc;
 	}

 	return 0;
 }

 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE

 static int dlpar_online_cpu(struct device_node *dn)
 {
 	int rc = 0;
 	unsigned int cpu;
 	int len, nthreads, i;
 	const __be32 *intserv;
 	u32 thread;

 	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
 	if (!intserv)
 		return -EINVAL;

 	nthreads = len / sizeof(u32);

 	cpu_maps_update_begin();
 	for (i = 0; i < nthreads; i++) {
 		thread = be32_to_cpu(intserv[i]);
 		for_each_present_cpu(cpu) {
 			if (get_hard_smp_processor_id(cpu) != thread)
 				continue;
 			BUG_ON(get_cpu_current_state(cpu)
 					!= CPU_STATE_OFFLINE);
 			cpu_maps_update_done();
 			rc = cpu_up(cpu);
 			if (rc)
 				goto out;
 			cpu_maps_update_begin();

 			break;
 		}
 		if (cpu == num_possible_cpus())
 			printk(KERN_WARNING "Could not find cpu to online "
 			       "with physical id 0x%x\n", thread);
 	}
 	cpu_maps_update_done();

 out:
 	return rc;

 }

 static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
 {
 	struct device_node *dn, *parent;
 	u32 drc_index;
 	int rc;

 	rc = kstrtou32(buf, 0, &drc_index);
 	if (rc)
 		return -EINVAL;

 	parent = of_find_node_by_path("/cpus");
 	if (!parent)
 		return -ENODEV;

 	dn = dlpar_configure_connector(drc_index, parent);
 	if (!dn)
 		return -EINVAL;

 	of_node_put(parent);

 	rc = dlpar_acquire_drc(drc_index);
 	if (rc) {
 		dlpar_free_cc_nodes(dn);
 		return -EINVAL;
 	}

 	rc = dlpar_attach_node(dn);
 	if (rc) {
 		dlpar_release_drc(drc_index);
 		dlpar_free_cc_nodes(dn);
 		return rc;
 	}

 	rc = dlpar_online_cpu(dn);
 	if (rc)
 		return rc;

 	return count;
 }

 static int dlpar_offline_cpu(struct device_node *dn)
 {
 	int rc = 0;
 	unsigned int cpu;
 	int len, nthreads, i;
 	const __be32 *intserv;
 	u32 thread;

 	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
 	if (!intserv)
 		return -EINVAL;

 	nthreads = len / sizeof(u32);

 	cpu_maps_update_begin();
 	for (i = 0; i < nthreads; i++) {
 		thread = be32_to_cpu(intserv[i]);
 		for_each_present_cpu(cpu) {
 			if (get_hard_smp_processor_id(cpu) != thread)
 				continue;

 			if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
 				break;

 			if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
 				set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
 				cpu_maps_update_done();
 				rc = cpu_down(cpu);
 				if (rc)
 					goto out;
 				cpu_maps_update_begin();
 				break;

 			}

 			/*
 			 * The cpu is in CPU_STATE_INACTIVE.
 			 * Upgrade it's state to CPU_STATE_OFFLINE.
 			 */
 			set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
 			BUG_ON(plpar_hcall_norets(H_PROD, thread)
 								!= H_SUCCESS);
 			__cpu_die(cpu);
 			break;
 		}
 		if (cpu == num_possible_cpus())
 			printk(KERN_WARNING "Could not find cpu to offline "
 			       "with physical id 0x%x\n", thread);
 	}
 	cpu_maps_update_done();

 out:
 	return rc;

 }

 static ssize_t dlpar_cpu_release(const char *buf, size_t count)
 {
 	struct device_node *dn;
 	u32 drc_index;
 	int rc;

 	dn = of_find_node_by_path(buf);
 	if (!dn)
 		return -EINVAL;

 	rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
 	if (rc) {
 		of_node_put(dn);
 		return -EINVAL;
 	}

 	rc = dlpar_offline_cpu(dn);
 	if (rc) {
 		of_node_put(dn);
 		return -EINVAL;
 	}

 	rc = dlpar_release_drc(drc_index);
 	if (rc) {
 		of_node_put(dn);
 		return rc;
 	}

 	rc = dlpar_detach_node(dn);
 	if (rc) {
 		dlpar_acquire_drc(drc_index);
 		return rc;
 	}

 	of_node_put(dn);

 	return count;
 }

 static int __init pseries_dlpar_init(void)
 {
 	ppc_md.cpu_probe = dlpar_cpu_probe;
 	ppc_md.cpu_release = dlpar_cpu_release;

 	return 0;
 }
 machine_device_initcall(pseries, pseries_dlpar_init);

 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
	/*
	* Support for dynamic reconfiguration for PCI, Memory, and CPU
	* Hotplug and Dynamic Logical Partitioning on RPA platforms.
	*
	* Copyright (C) 2009 Nathan Fontenot
	* Copyright (C) 2009 IBM Corporation
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License version
	* 2 as published by the Free Software Foundation.
	*/

	#include <linux/kernel.h>
	#include <linux/notifier.h>
	#include <linux/spinlock.h>
	#include <linux/cpu.h>
	#include <linux/slab.h>
	#include <linux/of.h>
	#include "offline_states.h"
	#include "pseries.h"

	#include <asm/prom.h>
	#include <asm/machdep.h>
	#include <asm/uaccess.h>
	#include <asm/rtas.h>

	struct cc_workarea {
	u32 drc_index;
	u32 zero;
	u32 name_offset;
	u32 prop_length;
	u32 prop_offset;
	};

	void dlpar_free_cc_property(struct property *prop)
	{
	kfree(prop->name);
	kfree(prop->value);
	kfree(prop);
	}

	static struct property dlpar_parse_cc_property(struct cc_workarea ccwa)
	{
	struct property *prop;
	char *name;
	char *value;

	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
	if (!prop)
	return NULL;

	name = (char *)ccwa + ccwa->name_offset;
	prop->name = kstrdup(name, GFP_KERNEL);

	prop->length = ccwa->prop_length;
	value = (char *)ccwa + ccwa->prop_offset;
	prop->value = kmemdup(value, prop->length, GFP_KERNEL);
	if (!prop->value) {
	dlpar_free_cc_property(prop);
	return NULL;
	}

	return prop;
	}

	static struct device_node dlpar_parse_cc_node(struct cc_workarea ccwa,
	const char *path)
	{
	struct device_node *dn;
	char *name;

	/* If parent node path is "/" advance path to NULL terminator to
	* prevent double leading slashs in full_name.
	*/
	if (!path[1])
	path++;

	dn = kzalloc(sizeof(*dn), GFP_KERNEL);
	if (!dn)
	return NULL;

	name = (char *)ccwa + ccwa->name_offset;
	dn->full_name = kasprintf(GFP_KERNEL, "%s/%s", path, name);
	if (!dn->full_name) {
	kfree(dn);
	return NULL;
	}

	of_node_set_flag(dn, OF_DYNAMIC);
	of_node_init(dn);

	return dn;
	}

	static void dlpar_free_one_cc_node(struct device_node *dn)
	{
	struct property *prop;

	while (dn->properties) {
	prop = dn->properties;
	dn->properties = prop->next;
	dlpar_free_cc_property(prop);
	}

	kfree(dn->full_name);
	kfree(dn);
	}

	void dlpar_free_cc_nodes(struct device_node *dn)
	{
	if (dn->child)
	dlpar_free_cc_nodes(dn->child);

	if (dn->sibling)
	dlpar_free_cc_nodes(dn->sibling);

	dlpar_free_one_cc_node(dn);
	}

	#define COMPLETE 0
	#define NEXT_SIBLING 1
	#define NEXT_CHILD 2
	#define NEXT_PROPERTY 3
	#define PREV_PARENT 4
	#define MORE_MEMORY 5
	#define CALL_AGAIN -2
	#define ERR_CFG_USE -9003

	struct device_node *dlpar_configure_connector(u32 drc_index,
	struct device_node *parent)
	{
	struct device_node *dn;
	struct device_node *first_dn = NULL;
	struct device_node *last_dn = NULL;
	struct property *property;
	struct property *last_property = NULL;
	struct cc_workarea *ccwa;
	char *data_buf;
	const char *parent_path = parent->full_name;
	int cc_token;
	int rc = -1;

	cc_token = rtas_token("ibm,configure-connector");
	if (cc_token == RTAS_UNKNOWN_SERVICE)
	return NULL;

	data_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
	if (!data_buf)
	return NULL;

	ccwa = (struct cc_workarea *)&data_buf[0];
	ccwa->drc_index = drc_index;
	ccwa->zero = 0;

	do {
	/* Since we release the rtas_data_buf lock between configure
	* connector calls we want to re-populate the rtas_data_buffer
	* with the contents of the previous call.
	*/
	spin_lock(&rtas_data_buf_lock);

	memcpy(rtas_data_buf, data_buf, RTAS_DATA_BUF_SIZE);
	rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL);
	memcpy(data_buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);

	spin_unlock(&rtas_data_buf_lock);

	switch (rc) {
	case COMPLETE:
	break;

	case NEXT_SIBLING:
	dn = dlpar_parse_cc_node(ccwa, parent_path);
	if (!dn)
	goto cc_error;

	dn->parent = last_dn->parent;
	last_dn->sibling = dn;
	last_dn = dn;
	break;

	case NEXT_CHILD:
	if (first_dn)
	parent_path = last_dn->full_name;

	dn = dlpar_parse_cc_node(ccwa, parent_path);
	if (!dn)
	goto cc_error;

	if (!first_dn) {
	dn->parent = parent;
	first_dn = dn;
	} else {
	dn->parent = last_dn;
	if (last_dn)
	last_dn->child = dn;
	}

	last_dn = dn;
	break;

	case NEXT_PROPERTY:
	property = dlpar_parse_cc_property(ccwa);
	if (!property)
	goto cc_error;

	if (!last_dn->properties)
	last_dn->properties = property;
	else
	last_property->next = property;

	last_property = property;
	break;

	case PREV_PARENT:
	last_dn = last_dn->parent;
	parent_path = last_dn->parent->full_name;
	break;

	case CALL_AGAIN:
	break;

	case MORE_MEMORY:
	case ERR_CFG_USE:
	default:
	printk(KERN_ERR "Unexpected Error (%d) "
	"returned from configure-connector\n", rc);
	goto cc_error;
	}
	} while (rc);

	cc_error:
	kfree(data_buf);

	if (rc) {
	if (first_dn)
	dlpar_free_cc_nodes(first_dn);

	return NULL;
	}

	return first_dn;
	}

	static struct device_node derive_parent(const char path)
	{
	struct device_node *parent;
	char *last_slash;

	last_slash = strrchr(path, '/');
	if (last_slash == path) {
	parent = of_find_node_by_path("/");
	} else {
	char *parent_path;
	int parent_path_len = last_slash - path + 1;
	parent_path = kmalloc(parent_path_len, GFP_KERNEL);
	if (!parent_path)
	return NULL;

	strlcpy(parent_path, path, parent_path_len);
	parent = of_find_node_by_path(parent_path);
	kfree(parent_path);
	}

	return parent;
	}

	int dlpar_attach_node(struct device_node *dn)
	{
	int rc;

	dn->parent = derive_parent(dn->full_name);
	if (!dn->parent)
	return -ENOMEM;

	rc = of_attach_node(dn);
	if (rc) {
	printk(KERN_ERR "Failed to add device node %s\n",
	dn->full_name);
	return rc;
	}

	of_node_put(dn->parent);
	return 0;
	}

	int dlpar_detach_node(struct device_node *dn)
	{
	struct device_node *child;
	int rc;

	child = of_get_next_child(dn, NULL);
	while (child) {
	dlpar_detach_node(child);
	child = of_get_next_child(dn, child);
	}

	rc = of_detach_node(dn);
	if (rc)
	return rc;

	of_node_put(dn); /* Must decrement the refcount */
	return 0;
	}

	#define DR_ENTITY_SENSE 9003
	#define DR_ENTITY_PRESENT 1
	#define DR_ENTITY_UNUSABLE 2
	#define ALLOCATION_STATE 9003
	#define ALLOC_UNUSABLE 0
	#define ALLOC_USABLE 1
	#define ISOLATION_STATE 9001
	#define ISOLATE 0
	#define UNISOLATE 1

	int dlpar_acquire_drc(u32 drc_index)
	{
	int dr_status, rc;

	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
	DR_ENTITY_SENSE, drc_index);
	if (rc \|\| dr_status != DR_ENTITY_UNUSABLE)
	return -1;

	rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_USABLE);
	if (rc)
	return rc;

	rc = rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
	if (rc) {
	rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
	return rc;
	}

	return 0;
	}

	int dlpar_release_drc(u32 drc_index)
	{
	int dr_status, rc;

	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
	DR_ENTITY_SENSE, drc_index);
	if (rc \|\| dr_status != DR_ENTITY_PRESENT)
	return -1;

	rc = rtas_set_indicator(ISOLATION_STATE, drc_index, ISOLATE);
	if (rc)
	return rc;

	rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
	if (rc) {
	rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
	return rc;
	}

	return 0;
	}

	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE

	static int dlpar_online_cpu(struct device_node *dn)
	{
	int rc = 0;
	unsigned int cpu;
	int len, nthreads, i;
	const __be32 *intserv;
	u32 thread;

	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
	if (!intserv)
	return -EINVAL;

	nthreads = len / sizeof(u32);

	cpu_maps_update_begin();
	for (i = 0; i < nthreads; i++) {
	thread = be32_to_cpu(intserv[i]);
	for_each_present_cpu(cpu) {
	if (get_hard_smp_processor_id(cpu) != thread)
	continue;
	BUG_ON(get_cpu_current_state(cpu)
	!= CPU_STATE_OFFLINE);
	cpu_maps_update_done();
	rc = cpu_up(cpu);
	if (rc)
	goto out;
	cpu_maps_update_begin();

	break;
	}
	if (cpu == num_possible_cpus())
	printk(KERN_WARNING "Could not find cpu to online "
	"with physical id 0x%x\n", thread);
	}
	cpu_maps_update_done();

	out:
	return rc;

	}

	static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
	{
	struct device_node dn, parent;
	u32 drc_index;
	int rc;

	rc = kstrtou32(buf, 0, &drc_index);
	if (rc)
	return -EINVAL;

	parent = of_find_node_by_path("/cpus");
	if (!parent)
	return -ENODEV;

	dn = dlpar_configure_connector(drc_index, parent);
	if (!dn)
	return -EINVAL;

	of_node_put(parent);

	rc = dlpar_acquire_drc(drc_index);
	if (rc) {
	dlpar_free_cc_nodes(dn);
	return -EINVAL;
	}

	rc = dlpar_attach_node(dn);
	if (rc) {
	dlpar_release_drc(drc_index);
	dlpar_free_cc_nodes(dn);
	return rc;
	}

	rc = dlpar_online_cpu(dn);
	if (rc)
	return rc;

	return count;
	}

	static int dlpar_offline_cpu(struct device_node *dn)
	{
	int rc = 0;
	unsigned int cpu;
	int len, nthreads, i;
	const __be32 *intserv;
	u32 thread;

	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
	if (!intserv)
	return -EINVAL;

	nthreads = len / sizeof(u32);

	cpu_maps_update_begin();
	for (i = 0; i < nthreads; i++) {
	thread = be32_to_cpu(intserv[i]);
	for_each_present_cpu(cpu) {
	if (get_hard_smp_processor_id(cpu) != thread)
	continue;

	if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
	break;

	if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
	set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
	cpu_maps_update_done();
	rc = cpu_down(cpu);
	if (rc)
	goto out;
	cpu_maps_update_begin();
	break;

	}

	/*
	* The cpu is in CPU_STATE_INACTIVE.
	* Upgrade it's state to CPU_STATE_OFFLINE.
	*/
	set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
	BUG_ON(plpar_hcall_norets(H_PROD, thread)
	!= H_SUCCESS);
	__cpu_die(cpu);
	break;
	}
	if (cpu == num_possible_cpus())
	printk(KERN_WARNING "Could not find cpu to offline "
	"with physical id 0x%x\n", thread);
	}
	cpu_maps_update_done();

	out:
	return rc;

	}

	static ssize_t dlpar_cpu_release(const char *buf, size_t count)
	{
	struct device_node *dn;
	u32 drc_index;
	int rc;

	dn = of_find_node_by_path(buf);
	if (!dn)
	return -EINVAL;

	rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
	if (rc) {
	of_node_put(dn);
	return -EINVAL;
	}

	rc = dlpar_offline_cpu(dn);
	if (rc) {
	of_node_put(dn);
	return -EINVAL;
	}

	rc = dlpar_release_drc(drc_index);
	if (rc) {
	of_node_put(dn);
	return rc;
	}

	rc = dlpar_detach_node(dn);
	if (rc) {
	dlpar_acquire_drc(drc_index);
	return rc;
	}

	of_node_put(dn);

	return count;
	}

	static int __init pseries_dlpar_init(void)
	{
	ppc_md.cpu_probe = dlpar_cpu_probe;
	ppc_md.cpu_release = dlpar_cpu_release;

	return 0;
	}
	machine_device_initcall(pseries, pseries_dlpar_init);

	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */