arch/powerpc/platforms/powernv/opal-dump.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * PowerNV OPAL Dump Interface
  *
  * Copyright 2013,2014 IBM Corp.
  */

 #include <linux/kobject.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>

 #include <asm/opal.h>

 #define DUMP_TYPE_FSP	0x01

 struct dump_obj {
 	struct kobject  kobj;
 	struct bin_attribute dump_attr;
 	uint32_t	id;  /* becomes object name */
 	uint32_t	type;
 	uint32_t	size;
 	char		*buffer;
 };
 #define to_dump_obj(x) container_of(x, struct dump_obj, kobj)

 struct dump_attribute {
 	struct attribute attr;
 	ssize_t (*show)(struct dump_obj *dump, struct dump_attribute *attr,
 			char *buf);
 	ssize_t (*store)(struct dump_obj *dump, struct dump_attribute *attr,
 			 const char *buf, size_t count);
 };
 #define to_dump_attr(x) container_of(x, struct dump_attribute, attr)

 static ssize_t dump_id_show(struct dump_obj *dump_obj,
 			    struct dump_attribute *attr,
 			    char *buf)
 {
 	return sprintf(buf, "0x%x\n", dump_obj->id);
 }

 static const char* dump_type_to_string(uint32_t type)
 {
 	switch (type) {
 	case 0x01: return "SP Dump";
 	case 0x02: return "System/Platform Dump";
 	case 0x03: return "SMA Dump";
 	default: return "unknown";
 	}
 }

 static ssize_t dump_type_show(struct dump_obj *dump_obj,
 			      struct dump_attribute *attr,
 			      char *buf)
 {

 	return sprintf(buf, "0x%x %s\n", dump_obj->type,
 		       dump_type_to_string(dump_obj->type));
 }

 static ssize_t dump_ack_show(struct dump_obj *dump_obj,
 			     struct dump_attribute *attr,
 			     char *buf)
 {
 	return sprintf(buf, "ack - acknowledge dump\n");
 }

 /*
  * Send acknowledgement to OPAL
  */
 static int64_t dump_send_ack(uint32_t dump_id)
 {
 	int rc;

 	rc = opal_dump_ack(dump_id);
 	if (rc)
 		pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
 			__func__, dump_id, rc);
 	return rc;
 }

 static ssize_t dump_ack_store(struct dump_obj *dump_obj,
 			      struct dump_attribute *attr,
 			      const char *buf,
 			      size_t count)
 {
 	/*
 	 * Try to self remove this attribute. If we are successful,
 	 * delete the kobject itself.
 	 */
 	if (sysfs_remove_file_self(&dump_obj->kobj, &attr->attr)) {
 		dump_send_ack(dump_obj->id);
 		kobject_put(&dump_obj->kobj);
 	}
 	return count;
 }

 /* Attributes of a dump
  * The binary attribute of the dump itself is dynamic
  * due to the dynamic size of the dump
  */
 static struct dump_attribute id_attribute =
 	__ATTR(id, 0444, dump_id_show, NULL);
 static struct dump_attribute type_attribute =
 	__ATTR(type, 0444, dump_type_show, NULL);
 static struct dump_attribute ack_attribute =
 	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);

 static ssize_t init_dump_show(struct dump_obj *dump_obj,
 			      struct dump_attribute *attr,
 			      char *buf)
 {
 	return sprintf(buf, "1 - initiate Service Processor(FSP) dump\n");
 }

 static int64_t dump_fips_init(uint8_t type)
 {
 	int rc;

 	rc = opal_dump_init(type);
 	if (rc)
 		pr_warn("%s: Failed to initiate FSP dump (%d)\n",
 			__func__, rc);
 	return rc;
 }

 static ssize_t init_dump_store(struct dump_obj *dump_obj,
 			       struct dump_attribute *attr,
 			       const char *buf,
 			       size_t count)
 {
 	int rc;

 	rc = dump_fips_init(DUMP_TYPE_FSP);
 	if (rc == OPAL_SUCCESS)
 		pr_info("%s: Initiated FSP dump\n", __func__);

 	return count;
 }

 static struct dump_attribute initiate_attribute =
 	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);

 static struct attribute *initiate_attrs[] = {
 	&initiate_attribute.attr,
 	NULL,
 };

 static struct attribute_group initiate_attr_group = {
 	.attrs = initiate_attrs,
 };

 static struct kset *dump_kset;

 static ssize_t dump_attr_show(struct kobject *kobj,
 			      struct attribute *attr,
 			      char *buf)
 {
 	struct dump_attribute *attribute;
 	struct dump_obj *dump;

 	attribute = to_dump_attr(attr);
 	dump = to_dump_obj(kobj);

 	if (!attribute->show)
 		return -EIO;

 	return attribute->show(dump, attribute, buf);
 }

 static ssize_t dump_attr_store(struct kobject *kobj,
 			       struct attribute *attr,
 			       const char *buf, size_t len)
 {
 	struct dump_attribute *attribute;
 	struct dump_obj *dump;

 	attribute = to_dump_attr(attr);
 	dump = to_dump_obj(kobj);

 	if (!attribute->store)
 		return -EIO;

 	return attribute->store(dump, attribute, buf, len);
 }

 static const struct sysfs_ops dump_sysfs_ops = {
 	.show = dump_attr_show,
 	.store = dump_attr_store,
 };

 static void dump_release(struct kobject *kobj)
 {
 	struct dump_obj *dump;

 	dump = to_dump_obj(kobj);
 	vfree(dump->buffer);
 	kfree(dump);
 }

 static struct attribute *dump_default_attrs[] = {
 	&id_attribute.attr,
 	&type_attribute.attr,
 	&ack_attribute.attr,
 	NULL,
 };

 static struct kobj_type dump_ktype = {
 	.sysfs_ops = &dump_sysfs_ops,
 	.release = &dump_release,
 	.default_attrs = dump_default_attrs,
 };

 static int64_t dump_read_info(uint32_t *dump_id, uint32_t *dump_size, uint32_t *dump_type)
 {
 	__be32 id, size, type;
 	int rc;

 	type = cpu_to_be32(0xffffffff);

 	rc = opal_dump_info2(&id, &size, &type);
 	if (rc == OPAL_PARAMETER)
 		rc = opal_dump_info(&id, &size);

 	if (rc) {
 		pr_warn("%s: Failed to get dump info (%d)\n",
 			__func__, rc);
 		return rc;
 	}

 	*dump_id = be32_to_cpu(id);
 	*dump_size = be32_to_cpu(size);
 	*dump_type = be32_to_cpu(type);

 	return rc;
 }

 static int64_t dump_read_data(struct dump_obj *dump)
 {
 	struct opal_sg_list *list;
 	uint64_t addr;
 	int64_t rc;

 	/* Allocate memory */
 	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
 	if (!dump->buffer) {
 		pr_err("%s : Failed to allocate memory\n", __func__);
 		rc = -ENOMEM;
 		goto out;
 	}

 	/* Generate SG list */
 	list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
 	if (!list) {
 		rc = -ENOMEM;
 		goto out;
 	}

 	/* First entry address */
 	addr = __pa(list);

 	/* Fetch data */
 	rc = OPAL_BUSY_EVENT;
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_dump_read(dump->id, addr);
 		if (rc == OPAL_BUSY_EVENT) {
 			opal_poll_events(NULL);
 			msleep(20);
 		}
 	}

 	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
 		pr_warn("%s: Extract dump failed for ID 0x%x\n",
 			__func__, dump->id);

 	/* Free SG list */
 	opal_free_sg_list(list);

 out:
 	return rc;
 }

 static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
 			      struct bin_attribute *bin_attr,
 			      char *buffer, loff_t pos, size_t count)
 {
 	ssize_t rc;

 	struct dump_obj *dump = to_dump_obj(kobj);

 	if (!dump->buffer) {
 		rc = dump_read_data(dump);

 		if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
 			vfree(dump->buffer);
 			dump->buffer = NULL;

 			return -EIO;
 		}
 		if (rc == OPAL_PARTIAL) {
 			/* On a partial read, we just return EIO
 			 * and rely on userspace to ask us to try
 			 * again.
 			 */
 			pr_info("%s: Platform dump partially read. ID = 0x%x\n",
 				__func__, dump->id);
 			return -EIO;
 		}
 	}

 	memcpy(buffer, dump->buffer + pos, count);

 	/* You may think we could free the dump buffer now and retrieve
 	 * it again later if needed, but due to current firmware limitation,
 	 * that's not the case. So, once read into userspace once,
 	 * we keep the dump around until it's acknowledged by userspace.
 	 */

 	return count;
 }

 static void create_dump_obj(uint32_t id, size_t size, uint32_t type)
 {
 	struct dump_obj *dump;
 	int rc;

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

 	dump->kobj.kset = dump_kset;

 	kobject_init(&dump->kobj, &dump_ktype);

 	sysfs_bin_attr_init(&dump->dump_attr);

 	dump->dump_attr.attr.name = "dump";
 	dump->dump_attr.attr.mode = 0400;
 	dump->dump_attr.size = size;
 	dump->dump_attr.read = dump_attr_read;

 	dump->id = id;
 	dump->size = size;
 	dump->type = type;

 	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
 	if (rc) {
 		kobject_put(&dump->kobj);
 		return;
 	}

 	/*
 	 * As soon as the sysfs file for this dump is created/activated there is
 	 * a chance the opal_errd daemon (or any userspace) might read and
 	 * acknowledge the dump before kobject_uevent() is called. If that
 	 * happens then there is a potential race between
 	 * dump_ack_store->kobject_put() and kobject_uevent() which leads to a
 	 * use-after-free of a kernfs object resulting in a kernel crash.
 	 *
 	 * To avoid that, we need to take a reference on behalf of the bin file,
 	 * so that our reference remains valid while we call kobject_uevent().
 	 * We then drop our reference before exiting the function, leaving the
 	 * bin file to drop the last reference (if it hasn't already).
 	 */

 	/* Take a reference for the bin file */
 	kobject_get(&dump->kobj);
 	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
 	if (rc == 0) {
 		kobject_uevent(&dump->kobj, KOBJ_ADD);

 		pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
 			__func__, dump->id, dump->size);
 	} else {
 		/* Drop reference count taken for bin file */
 		kobject_put(&dump->kobj);
 	}

 	/* Drop our reference */
 	kobject_put(&dump->kobj);
 	return;
 }

 static irqreturn_t process_dump(int irq, void *data)
 {
 	int rc;
 	uint32_t dump_id, dump_size, dump_type;
 	char name[22];
 	struct kobject *kobj;

 	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
 	if (rc != OPAL_SUCCESS)
 		return IRQ_HANDLED;

 	sprintf(name, "0x%x-0x%x", dump_type, dump_id);

 	/* we may get notified twice, let's handle
 	 * that gracefully and not create two conflicting
 	 * entries.
 	 */
 	kobj = kset_find_obj(dump_kset, name);
 	if (kobj) {
 		/* Drop reference added by kset_find_obj() */
 		kobject_put(kobj);
 		return IRQ_HANDLED;
 	}

 	create_dump_obj(dump_id, dump_size, dump_type);

 	return IRQ_HANDLED;
 }

 void __init opal_platform_dump_init(void)
 {
 	int rc;
 	int dump_irq;

 	/* ELOG not supported by firmware */
 	if (!opal_check_token(OPAL_DUMP_READ))
 		return;

 	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
 	if (!dump_kset) {
 		pr_warn("%s: Failed to create dump kset\n", __func__);
 		return;
 	}

 	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
 	if (rc) {
 		pr_warn("%s: Failed to create initiate dump attr group\n",
 			__func__);
 		kobject_put(&dump_kset->kobj);
 		return;
 	}

 	dump_irq = opal_event_request(ilog2(OPAL_EVENT_DUMP_AVAIL));
 	if (!dump_irq) {
 		pr_err("%s: Can't register OPAL event irq (%d)\n",
 		       __func__, dump_irq);
 		return;
 	}

 	rc = request_threaded_irq(dump_irq, NULL, process_dump,
 				IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 				"opal-dump", NULL);
 	if (rc) {
 		pr_err("%s: Can't request OPAL event irq (%d)\n",
 		       __func__, rc);
 		return;
 	}

 	if (opal_check_token(OPAL_DUMP_RESEND))
 		opal_dump_resend_notification();
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* PowerNV OPAL Dump Interface
	*
	* Copyright 2013,2014 IBM Corp.
	*/

	#include <linux/kobject.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/vmalloc.h>
	#include <linux/pagemap.h>
	#include <linux/delay.h>
	#include <linux/interrupt.h>

	#include <asm/opal.h>

	#define DUMP_TYPE_FSP 0x01

	struct dump_obj {
	struct kobject kobj;
	struct bin_attribute dump_attr;
	uint32_t id; /* becomes object name */
	uint32_t type;
	uint32_t size;
	char *buffer;
	};
	#define to_dump_obj(x) container_of(x, struct dump_obj, kobj)

	struct dump_attribute {
	struct attribute attr;
	ssize_t (show)(struct dump_obj dump, struct dump_attribute *attr,
	char *buf);
	ssize_t (store)(struct dump_obj dump, struct dump_attribute *attr,
	const char *buf, size_t count);
	};
	#define to_dump_attr(x) container_of(x, struct dump_attribute, attr)

	static ssize_t dump_id_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "0x%x\n", dump_obj->id);
	}

	static const char* dump_type_to_string(uint32_t type)
	{
	switch (type) {
	case 0x01: return "SP Dump";
	case 0x02: return "System/Platform Dump";
	case 0x03: return "SMA Dump";
	default: return "unknown";
	}
	}

	static ssize_t dump_type_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{

	return sprintf(buf, "0x%x %s\n", dump_obj->type,
	dump_type_to_string(dump_obj->type));
	}

	static ssize_t dump_ack_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "ack - acknowledge dump\n");
	}

	/*
	* Send acknowledgement to OPAL
	*/
	static int64_t dump_send_ack(uint32_t dump_id)
	{
	int rc;

	rc = opal_dump_ack(dump_id);
	if (rc)
	pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
	__func__, dump_id, rc);
	return rc;
	}

	static ssize_t dump_ack_store(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	const char *buf,
	size_t count)
	{
	/*
	* Try to self remove this attribute. If we are successful,
	* delete the kobject itself.
	*/
	if (sysfs_remove_file_self(&dump_obj->kobj, &attr->attr)) {
	dump_send_ack(dump_obj->id);
	kobject_put(&dump_obj->kobj);
	}
	return count;
	}

	/* Attributes of a dump
	* The binary attribute of the dump itself is dynamic
	* due to the dynamic size of the dump
	*/
	static struct dump_attribute id_attribute =
	__ATTR(id, 0444, dump_id_show, NULL);
	static struct dump_attribute type_attribute =
	__ATTR(type, 0444, dump_type_show, NULL);
	static struct dump_attribute ack_attribute =
	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);

	static ssize_t init_dump_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "1 - initiate Service Processor(FSP) dump\n");
	}

	static int64_t dump_fips_init(uint8_t type)
	{
	int rc;

	rc = opal_dump_init(type);
	if (rc)
	pr_warn("%s: Failed to initiate FSP dump (%d)\n",
	__func__, rc);
	return rc;
	}

	static ssize_t init_dump_store(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	const char *buf,
	size_t count)
	{
	int rc;

	rc = dump_fips_init(DUMP_TYPE_FSP);
	if (rc == OPAL_SUCCESS)
	pr_info("%s: Initiated FSP dump\n", __func__);

	return count;
	}

	static struct dump_attribute initiate_attribute =
	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);

	static struct attribute *initiate_attrs[] = {
	&initiate_attribute.attr,
	NULL,
	};

	static struct attribute_group initiate_attr_group = {
	.attrs = initiate_attrs,
	};

	static struct kset *dump_kset;

	static ssize_t dump_attr_show(struct kobject *kobj,
	struct attribute *attr,
	char *buf)
	{
	struct dump_attribute *attribute;
	struct dump_obj *dump;

	attribute = to_dump_attr(attr);
	dump = to_dump_obj(kobj);

	if (!attribute->show)
	return -EIO;

	return attribute->show(dump, attribute, buf);
	}

	static ssize_t dump_attr_store(struct kobject *kobj,
	struct attribute *attr,
	const char *buf, size_t len)
	{
	struct dump_attribute *attribute;
	struct dump_obj *dump;

	attribute = to_dump_attr(attr);
	dump = to_dump_obj(kobj);

	if (!attribute->store)
	return -EIO;

	return attribute->store(dump, attribute, buf, len);
	}

	static const struct sysfs_ops dump_sysfs_ops = {
	.show = dump_attr_show,
	.store = dump_attr_store,
	};

	static void dump_release(struct kobject *kobj)
	{
	struct dump_obj *dump;

	dump = to_dump_obj(kobj);
	vfree(dump->buffer);
	kfree(dump);
	}

	static struct attribute *dump_default_attrs[] = {
	&id_attribute.attr,
	&type_attribute.attr,
	&ack_attribute.attr,
	NULL,
	};

	static struct kobj_type dump_ktype = {
	.sysfs_ops = &dump_sysfs_ops,
	.release = &dump_release,
	.default_attrs = dump_default_attrs,
	};

	static int64_t dump_read_info(uint32_t dump_id, uint32_t dump_size, uint32_t *dump_type)
	{
	__be32 id, size, type;
	int rc;

	type = cpu_to_be32(0xffffffff);

	rc = opal_dump_info2(&id, &size, &type);
	if (rc == OPAL_PARAMETER)
	rc = opal_dump_info(&id, &size);

	if (rc) {
	pr_warn("%s: Failed to get dump info (%d)\n",
	__func__, rc);
	return rc;
	}

	*dump_id = be32_to_cpu(id);
	*dump_size = be32_to_cpu(size);
	*dump_type = be32_to_cpu(type);

	return rc;
	}

	static int64_t dump_read_data(struct dump_obj *dump)
	{
	struct opal_sg_list *list;
	uint64_t addr;
	int64_t rc;

	/* Allocate memory */
	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
	if (!dump->buffer) {
	pr_err("%s : Failed to allocate memory\n", __func__);
	rc = -ENOMEM;
	goto out;
	}

	/* Generate SG list */
	list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
	if (!list) {
	rc = -ENOMEM;
	goto out;
	}

	/* First entry address */
	addr = __pa(list);

	/* Fetch data */
	rc = OPAL_BUSY_EVENT;
	while (rc == OPAL_BUSY \|\| rc == OPAL_BUSY_EVENT) {
	rc = opal_dump_read(dump->id, addr);
	if (rc == OPAL_BUSY_EVENT) {
	opal_poll_events(NULL);
	msleep(20);
	}
	}

	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
	pr_warn("%s: Extract dump failed for ID 0x%x\n",
	__func__, dump->id);

	/* Free SG list */
	opal_free_sg_list(list);

	out:
	return rc;
	}

	static ssize_t dump_attr_read(struct file filep, struct kobject kobj,
	struct bin_attribute *bin_attr,
	char *buffer, loff_t pos, size_t count)
	{
	ssize_t rc;

	struct dump_obj *dump = to_dump_obj(kobj);

	if (!dump->buffer) {
	rc = dump_read_data(dump);

	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
	vfree(dump->buffer);
	dump->buffer = NULL;

	return -EIO;
	}
	if (rc == OPAL_PARTIAL) {
	/* On a partial read, we just return EIO
	* and rely on userspace to ask us to try
	* again.
	*/
	pr_info("%s: Platform dump partially read. ID = 0x%x\n",
	__func__, dump->id);
	return -EIO;
	}
	}

	memcpy(buffer, dump->buffer + pos, count);

	/* You may think we could free the dump buffer now and retrieve
	* it again later if needed, but due to current firmware limitation,
	* that's not the case. So, once read into userspace once,
	* we keep the dump around until it's acknowledged by userspace.
	*/

	return count;
	}

	static void create_dump_obj(uint32_t id, size_t size, uint32_t type)
	{
	struct dump_obj *dump;
	int rc;

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

	dump->kobj.kset = dump_kset;

	kobject_init(&dump->kobj, &dump_ktype);

	sysfs_bin_attr_init(&dump->dump_attr);

	dump->dump_attr.attr.name = "dump";
	dump->dump_attr.attr.mode = 0400;
	dump->dump_attr.size = size;
	dump->dump_attr.read = dump_attr_read;

	dump->id = id;
	dump->size = size;
	dump->type = type;

	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
	if (rc) {
	kobject_put(&dump->kobj);
	return;
	}

	/*
	* As soon as the sysfs file for this dump is created/activated there is
	* a chance the opal_errd daemon (or any userspace) might read and
	* acknowledge the dump before kobject_uevent() is called. If that
	* happens then there is a potential race between
	* dump_ack_store->kobject_put() and kobject_uevent() which leads to a
	* use-after-free of a kernfs object resulting in a kernel crash.
	*
	* To avoid that, we need to take a reference on behalf of the bin file,
	* so that our reference remains valid while we call kobject_uevent().
	* We then drop our reference before exiting the function, leaving the
	* bin file to drop the last reference (if it hasn't already).
	*/

	/* Take a reference for the bin file */
	kobject_get(&dump->kobj);
	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
	if (rc == 0) {
	kobject_uevent(&dump->kobj, KOBJ_ADD);

	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
	__func__, dump->id, dump->size);
	} else {
	/* Drop reference count taken for bin file */
	kobject_put(&dump->kobj);
	}

	/* Drop our reference */
	kobject_put(&dump->kobj);
	return;
	}

	static irqreturn_t process_dump(int irq, void *data)
	{
	int rc;
	uint32_t dump_id, dump_size, dump_type;
	char name[22];
	struct kobject *kobj;

	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
	if (rc != OPAL_SUCCESS)
	return IRQ_HANDLED;

	sprintf(name, "0x%x-0x%x", dump_type, dump_id);

	/* we may get notified twice, let's handle
	* that gracefully and not create two conflicting
	* entries.
	*/
	kobj = kset_find_obj(dump_kset, name);
	if (kobj) {
	/* Drop reference added by kset_find_obj() */
	kobject_put(kobj);
	return IRQ_HANDLED;
	}

	create_dump_obj(dump_id, dump_size, dump_type);

	return IRQ_HANDLED;
	}

	void __init opal_platform_dump_init(void)
	{
	int rc;
	int dump_irq;

	/* ELOG not supported by firmware */
	if (!opal_check_token(OPAL_DUMP_READ))
	return;

	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
	if (!dump_kset) {
	pr_warn("%s: Failed to create dump kset\n", __func__);
	return;
	}

	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
	if (rc) {
	pr_warn("%s: Failed to create initiate dump attr group\n",
	__func__);
	kobject_put(&dump_kset->kobj);
	return;
	}

	dump_irq = opal_event_request(ilog2(OPAL_EVENT_DUMP_AVAIL));
	if (!dump_irq) {
	pr_err("%s: Can't register OPAL event irq (%d)\n",
	__func__, dump_irq);
	return;
	}

	rc = request_threaded_irq(dump_irq, NULL, process_dump,
	IRQF_TRIGGER_HIGH \| IRQF_ONESHOT,
	"opal-dump", NULL);
	if (rc) {
	pr_err("%s: Can't request OPAL event irq (%d)\n",
	__func__, rc);
	return;
	}

	if (opal_check_token(OPAL_DUMP_RESEND))
	opal_dump_resend_notification();
	}