Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 697 insertions, 0 deletions

diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
new file mode 100644
index 000000000..cda53d037
--- /dev/null
+++ b/drivers/firmware/dmi-sysfs.c
@@ -0,0 +1,697 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * dmi-sysfs.c
+ *
+ * This module exports the DMI tables read-only to userspace through the
+ * sysfs file system.
+ *
+ * Data is currently found below
+ *    /sys/firmware/dmi/...
+ *
+ * DMI attributes are presented in attribute files with names
+ * formatted using %d-%d, so that the first integer indicates the
+ * structure type (0-255), and the second field is the instance of that
+ * entry.
+ *
+ * Copyright 2011 Google, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kobject.h>
+#include <linux/dmi.h>
+#include <linux/capability.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/io.h>
+#include <asm/dmi.h>
+
+#define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
+			      the top entry type is only 8 bits */
+
+struct dmi_sysfs_entry {
+	struct dmi_header dh;
+	struct kobject kobj;
+	int instance;
+	int position;
+	struct list_head list;
+	struct kobject *child;
+};
+
+/*
+ * Global list of dmi_sysfs_entry.  Even though this should only be
+ * manipulated at setup and teardown, the lazy nature of the kobject
+ * system means we get lazy removes.
+ */
+static LIST_HEAD(entry_list);
+static DEFINE_SPINLOCK(entry_list_lock);
+
+/* dmi_sysfs_attribute - Top level attribute. used by all entries. */
+struct dmi_sysfs_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
+};
+
+#define DMI_SYSFS_ATTR(_entry, _name) \
+struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
+	.attr = {.name = __stringify(_name), .mode = 0400}, \
+	.show = dmi_sysfs_##_entry##_##_name, \
+}
+
+/*
+ * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
+ * mapped in.  Use in conjunction with dmi_sysfs_specialize_attr_ops.
+ */
+struct dmi_sysfs_mapped_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct dmi_sysfs_entry *entry,
+			const struct dmi_header *dh,
+			char *buf);
+};
+
+#define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
+struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
+	.attr = {.name = __stringify(_name), .mode = 0400}, \
+	.show = dmi_sysfs_##_entry##_##_name, \
+}
+
+/*************************************************
+ * Generic DMI entry support.
+ *************************************************/
+static void dmi_entry_free(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
+{
+	return container_of(kobj, struct dmi_sysfs_entry, kobj);
+}
+
+static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
+{
+	return container_of(attr, struct dmi_sysfs_attribute, attr);
+}
+
+static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
+				   struct attribute *_attr, char *buf)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj);
+	struct dmi_sysfs_attribute *attr = to_attr(_attr);
+
+	/* DMI stuff is only ever admin visible */
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	return attr->show(entry, buf);
+}
+
+static const struct sysfs_ops dmi_sysfs_attr_ops = {
+	.show = dmi_sysfs_attr_show,
+};
+
+typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
+				const struct dmi_header *dh, void *);
+
+struct find_dmi_data {
+	struct dmi_sysfs_entry	*entry;
+	dmi_callback		callback;
+	void			*private;
+	int			instance_countdown;
+	ssize_t			ret;
+};
+
+static void find_dmi_entry_helper(const struct dmi_header *dh,
+				  void *_data)
+{
+	struct find_dmi_data *data = _data;
+	struct dmi_sysfs_entry *entry = data->entry;
+
+	/* Is this the entry we want? */
+	if (dh->type != entry->dh.type)
+		return;
+
+	if (data->instance_countdown != 0) {
+		/* try the next instance? */
+		data->instance_countdown--;
+		return;
+	}
+
+	/*
+	 * Don't ever revisit the instance.  Short circuit later
+	 * instances by letting the instance_countdown run negative
+	 */
+	data->instance_countdown--;
+
+	/* Found the entry */
+	data->ret = data->callback(entry, dh, data->private);
+}
+
+/* State for passing the read parameters through dmi_find_entry() */
+struct dmi_read_state {
+	char *buf;
+	loff_t pos;
+	size_t count;
+};
+
+static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
+			      dmi_callback callback, void *private)
+{
+	struct find_dmi_data data = {
+		.entry = entry,
+		.callback = callback,
+		.private = private,
+		.instance_countdown = entry->instance,
+		.ret = -EIO,  /* To signal the entry disappeared */
+	};
+	int ret;
+
+	ret = dmi_walk(find_dmi_entry_helper, &data);
+	/* This shouldn't happen, but just in case. */
+	if (ret)
+		return -EINVAL;
+	return data.ret;
+}
+
+/*
+ * Calculate and return the byte length of the dmi entry identified by
+ * dh.  This includes both the formatted portion as well as the
+ * unformatted string space, including the two trailing nul characters.
+ */
+static size_t dmi_entry_length(const struct dmi_header *dh)
+{
+	const char *p = (const char *)dh;
+
+	p += dh->length;
+
+	while (p[0] || p[1])
+		p++;
+
+	return 2 + p - (const char *)dh;
+}
+
+/*************************************************
+ * Support bits for specialized DMI entry support
+ *************************************************/
+struct dmi_entry_attr_show_data {
+	struct attribute *attr;
+	char *buf;
+};
+
+static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
+					  const struct dmi_header *dh,
+					  void *_data)
+{
+	struct dmi_entry_attr_show_data *data = _data;
+	struct dmi_sysfs_mapped_attribute *attr;
+
+	attr = container_of(data->attr,
+			    struct dmi_sysfs_mapped_attribute, attr);
+	return attr->show(entry, dh, data->buf);
+}
+
+static ssize_t dmi_entry_attr_show(struct kobject *kobj,
+				   struct attribute *attr,
+				   char *buf)
+{
+	struct dmi_entry_attr_show_data data = {
+		.attr = attr,
+		.buf  = buf,
+	};
+	/* Find the entry according to our parent and call the
+	 * normalized show method hanging off of the attribute */
+	return find_dmi_entry(to_entry(kobj->parent),
+			      dmi_entry_attr_show_helper, &data);
+}
+
+static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
+	.show = dmi_entry_attr_show,
+};
+
+/*************************************************
+ * Specialized DMI entry support.
+ *************************************************/
+
+/*** Type 15 - System Event Table ***/
+
+#define DMI_SEL_ACCESS_METHOD_IO8	0x00
+#define DMI_SEL_ACCESS_METHOD_IO2x8	0x01
+#define DMI_SEL_ACCESS_METHOD_IO16	0x02
+#define DMI_SEL_ACCESS_METHOD_PHYS32	0x03
+#define DMI_SEL_ACCESS_METHOD_GPNV	0x04
+
+struct dmi_system_event_log {
+	struct dmi_header header;
+	u16	area_length;
+	u16	header_start_offset;
+	u16	data_start_offset;
+	u8	access_method;
+	u8	status;
+	u32	change_token;
+	union {
+		struct {
+			u16 index_addr;
+			u16 data_addr;
+		} io;
+		u32	phys_addr32;
+		u16	gpnv_handle;
+		u32	access_method_address;
+	};
+	u8	header_format;
+	u8	type_descriptors_supported_count;
+	u8	per_log_type_descriptor_length;
+	u8	supported_log_type_descriptos[];
+} __packed;
+
+#define DMI_SYSFS_SEL_FIELD(_field) \
+static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
+				      const struct dmi_header *dh, \
+				      char *buf) \
+{ \
+	struct dmi_system_event_log sel; \
+	if (sizeof(sel) > dmi_entry_length(dh)) \
+		return -EIO; \
+	memcpy(&sel, dh, sizeof(sel)); \
+	return sprintf(buf, "%u\n", sel._field); \
+} \
+static DMI_SYSFS_MAPPED_ATTR(sel, _field)
+
+DMI_SYSFS_SEL_FIELD(area_length);
+DMI_SYSFS_SEL_FIELD(header_start_offset);
+DMI_SYSFS_SEL_FIELD(data_start_offset);
+DMI_SYSFS_SEL_FIELD(access_method);
+DMI_SYSFS_SEL_FIELD(status);
+DMI_SYSFS_SEL_FIELD(change_token);
+DMI_SYSFS_SEL_FIELD(access_method_address);
+DMI_SYSFS_SEL_FIELD(header_format);
+DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
+DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);
+
+static struct attribute *dmi_sysfs_sel_attrs[] = {
+	&dmi_sysfs_attr_sel_area_length.attr,
+	&dmi_sysfs_attr_sel_header_start_offset.attr,
+	&dmi_sysfs_attr_sel_data_start_offset.attr,
+	&dmi_sysfs_attr_sel_access_method.attr,
+	&dmi_sysfs_attr_sel_status.attr,
+	&dmi_sysfs_attr_sel_change_token.attr,
+	&dmi_sysfs_attr_sel_access_method_address.attr,
+	&dmi_sysfs_attr_sel_header_format.attr,
+	&dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
+	&dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(dmi_sysfs_sel);
+
+static const struct kobj_type dmi_system_event_log_ktype = {
+	.release = dmi_entry_free,
+	.sysfs_ops = &dmi_sysfs_specialize_attr_ops,
+	.default_groups = dmi_sysfs_sel_groups,
+};
+
+#ifdef CONFIG_HAS_IOPORT
+typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
+			    loff_t offset);
+
+static DEFINE_MUTEX(io_port_lock);
+
+static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
+				   loff_t offset)
+{
+	u8 ret;
+
+	mutex_lock(&io_port_lock);
+	outb((u8)offset, sel->io.index_addr);
+	ret = inb(sel->io.data_addr);
+	mutex_unlock(&io_port_lock);
+	return ret;
+}
+
+static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
+				     loff_t offset)
+{
+	u8 ret;
+
+	mutex_lock(&io_port_lock);
+	outb((u8)offset, sel->io.index_addr);
+	outb((u8)(offset >> 8), sel->io.index_addr + 1);
+	ret = inb(sel->io.data_addr);
+	mutex_unlock(&io_port_lock);
+	return ret;
+}
+
+static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
+				    loff_t offset)
+{
+	u8 ret;
+
+	mutex_lock(&io_port_lock);
+	outw((u16)offset, sel->io.index_addr);
+	ret = inb(sel->io.data_addr);
+	mutex_unlock(&io_port_lock);
+	return ret;
+}
+
+static sel_io_reader sel_io_readers[] = {
+	[DMI_SEL_ACCESS_METHOD_IO8]	= read_sel_8bit_indexed_io,
+	[DMI_SEL_ACCESS_METHOD_IO2x8]	= read_sel_2x8bit_indexed_io,
+	[DMI_SEL_ACCESS_METHOD_IO16]	= read_sel_16bit_indexed_io,
+};
+
+static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
+				   const struct dmi_system_event_log *sel,
+				   char *buf, loff_t pos, size_t count)
+{
+	ssize_t wrote = 0;
+
+	sel_io_reader io_reader = sel_io_readers[sel->access_method];
+
+	while (count && pos < sel->area_length) {
+		count--;
+		*(buf++) = io_reader(sel, pos++);
+		wrote++;
+	}
+
+	return wrote;
+}
+#endif
+
+static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
+				       const struct dmi_system_event_log *sel,
+				       char *buf, loff_t pos, size_t count)
+{
+	u8 __iomem *mapped;
+	ssize_t wrote = 0;
+
+	mapped = dmi_remap(sel->access_method_address, sel->area_length);
+	if (!mapped)
+		return -EIO;
+
+	while (count && pos < sel->area_length) {
+		count--;
+		*(buf++) = readb(mapped + pos++);
+		wrote++;
+	}
+
+	dmi_unmap(mapped);
+	return wrote;
+}
+
+static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
+				       const struct dmi_header *dh,
+				       void *_state)
+{
+	struct dmi_read_state *state = _state;
+	struct dmi_system_event_log sel;
+
+	if (sizeof(sel) > dmi_entry_length(dh))
+		return -EIO;
+
+	memcpy(&sel, dh, sizeof(sel));
+
+	switch (sel.access_method) {
+#ifdef CONFIG_HAS_IOPORT
+	case DMI_SEL_ACCESS_METHOD_IO8:
+	case DMI_SEL_ACCESS_METHOD_IO2x8:
+	case DMI_SEL_ACCESS_METHOD_IO16:
+		return dmi_sel_raw_read_io(entry, &sel, state->buf,
+					   state->pos, state->count);
+#endif
+	case DMI_SEL_ACCESS_METHOD_PHYS32:
+		return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
+					       state->pos, state->count);
+	case DMI_SEL_ACCESS_METHOD_GPNV:
+		pr_info_ratelimited("dmi-sysfs: GPNV support missing.\n");
+		return -EIO;
+	default:
+		pr_info_ratelimited("dmi-sysfs: Unknown access method %02x\n",
+			sel.access_method);
+		return -EIO;
+	}
+}
+
+static ssize_t raw_event_log_read(struct file *filp, struct kobject *kobj,
+				  const struct bin_attribute *bin_attr,
+				  char *buf, loff_t pos, size_t count)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
+	struct dmi_read_state state = {
+		.buf = buf,
+		.pos = pos,
+		.count = count,
+	};
+
+	return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
+}
+
+static const BIN_ATTR_ADMIN_RO(raw_event_log, 0);
+
+static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
+{
+	int ret;
+
+	entry->child = kzalloc_obj(*entry->child);
+	if (!entry->child)
+		return -ENOMEM;
+	ret = kobject_init_and_add(entry->child,
+				   &dmi_system_event_log_ktype,
+				   &entry->kobj,
+				   "system_event_log");
+	if (ret)
+		goto out_free;
+
+	ret = sysfs_create_bin_file(entry->child, &bin_attr_raw_event_log);
+	if (ret)
+		goto out_del;
+
+	return 0;
+
+out_del:
+	kobject_del(entry->child);
+out_free:
+	kfree(entry->child);
+	return ret;
+}
+
+/*************************************************
+ * Generic DMI entry support.
+ *************************************************/
+
+static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
+{
+	return sprintf(buf, "%d\n", entry->dh.length);
+}
+
+static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
+{
+	return sprintf(buf, "%d\n", entry->dh.handle);
+}
+
+static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
+{
+	return sprintf(buf, "%d\n", entry->dh.type);
+}
+
+static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
+					char *buf)
+{
+	return sprintf(buf, "%d\n", entry->instance);
+}
+
+static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
+					char *buf)
+{
+	return sprintf(buf, "%d\n", entry->position);
+}
+
+static DMI_SYSFS_ATTR(entry, length);
+static DMI_SYSFS_ATTR(entry, handle);
+static DMI_SYSFS_ATTR(entry, type);
+static DMI_SYSFS_ATTR(entry, instance);
+static DMI_SYSFS_ATTR(entry, position);
+
+static struct attribute *dmi_sysfs_entry_attrs[] = {
+	&dmi_sysfs_attr_entry_length.attr,
+	&dmi_sysfs_attr_entry_handle.attr,
+	&dmi_sysfs_attr_entry_type.attr,
+	&dmi_sysfs_attr_entry_instance.attr,
+	&dmi_sysfs_attr_entry_position.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(dmi_sysfs_entry);
+
+static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
+					 const struct dmi_header *dh,
+					 void *_state)
+{
+	struct dmi_read_state *state = _state;
+	size_t entry_length;
+
+	entry_length = dmi_entry_length(dh);
+
+	return memory_read_from_buffer(state->buf, state->count,
+				       &state->pos, dh, entry_length);
+}
+
+static ssize_t raw_read(struct file *filp,
+			struct kobject *kobj,
+			const struct bin_attribute *bin_attr,
+			char *buf, loff_t pos, size_t count)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj);
+	struct dmi_read_state state = {
+		.buf = buf,
+		.pos = pos,
+		.count = count,
+	};
+
+	return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
+}
+
+static const BIN_ATTR_ADMIN_RO(raw, 0);
+
+static void dmi_sysfs_entry_release(struct kobject *kobj)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj);
+
+	spin_lock(&entry_list_lock);
+	list_del(&entry->list);
+	spin_unlock(&entry_list_lock);
+	kfree(entry);
+}
+
+static const struct kobj_type dmi_sysfs_entry_ktype = {
+	.release = dmi_sysfs_entry_release,
+	.sysfs_ops = &dmi_sysfs_attr_ops,
+	.default_groups = dmi_sysfs_entry_groups,
+};
+
+static struct kset *dmi_kset;
+
+/* Global count of all instances seen.  Only for setup */
+static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];
+
+/* Global positional count of all entries seen.  Only for setup */
+static int __initdata position_count;
+
+static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
+					     void *_ret)
+{
+	struct dmi_sysfs_entry *entry;
+	int *ret = _ret;
+
+	/* If a previous entry saw an error, short circuit */
+	if (*ret)
+		return;
+
+	/* Allocate and register a new entry into the entries set */
+	entry = kzalloc_obj(*entry);
+	if (!entry) {
+		*ret = -ENOMEM;
+		return;
+	}
+
+	/* Set the key */
+	memcpy(&entry->dh, dh, sizeof(*dh));
+	entry->instance = instance_counts[dh->type]++;
+	entry->position = position_count++;
+
+	entry->kobj.kset = dmi_kset;
+	*ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
+				    "%d-%d", dh->type, entry->instance);
+
+	/* Thread on the global list for cleanup */
+	spin_lock(&entry_list_lock);
+	list_add_tail(&entry->list, &entry_list);
+	spin_unlock(&entry_list_lock);
+
+	if (*ret) {
+		kobject_put(&entry->kobj);
+		return;
+	}
+
+	/* Handle specializations by type */
+	switch (dh->type) {
+	case DMI_ENTRY_SYSTEM_EVENT_LOG:
+		*ret = dmi_system_event_log(entry);
+		break;
+	default:
+		/* No specialization */
+		break;
+	}
+	if (*ret)
+		goto out_err;
+
+	/* Create the raw binary file to access the entry */
+	*ret = sysfs_create_bin_file(&entry->kobj, &bin_attr_raw);
+	if (*ret)
+		goto out_err;
+
+	return;
+out_err:
+	kobject_put(entry->child);
+	kobject_put(&entry->kobj);
+	return;
+}
+
+static void cleanup_entry_list(void)
+{
+	struct dmi_sysfs_entry *entry, *next;
+
+	/* No locks, we are on our way out */
+	list_for_each_entry_safe(entry, next, &entry_list, list) {
+		kobject_put(entry->child);
+		kobject_put(&entry->kobj);
+	}
+}
+
+static int __init dmi_sysfs_init(void)
+{
+	int error;
+	int val;
+
+	if (!dmi_kobj) {
+		pr_debug("dmi-sysfs: dmi entry is absent.\n");
+		error = -ENODATA;
+		goto err;
+	}
+
+	dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
+	if (!dmi_kset) {
+		error = -ENOMEM;
+		goto err;
+	}
+
+	val = 0;
+	error = dmi_walk(dmi_sysfs_register_handle, &val);
+	if (error)
+		goto err;
+	if (val) {
+		error = val;
+		goto err;
+	}
+
+	pr_debug("dmi-sysfs: loaded.\n");
+
+	return 0;
+err:
+	cleanup_entry_list();
+	kset_unregister(dmi_kset);
+	return error;
+}
+
+/* clean up everything. */
+static void __exit dmi_sysfs_exit(void)
+{
+	pr_debug("dmi-sysfs: unloading.\n");
+	cleanup_entry_list();
+	kset_unregister(dmi_kset);
+}
+
+module_init(dmi_sysfs_init);
+module_exit(dmi_sysfs_exit);
+
+MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
+MODULE_DESCRIPTION("DMI sysfs support");
+MODULE_LICENSE("GPL");