Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1436 insertions, 0 deletions

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
new file mode 100644
index 000000000..08de6652a
--- /dev/null
+++ b/fs/debugfs/file.c
@@ -0,0 +1,1436 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  file.c - part of debugfs, a tiny little debug file system
+ *
+ *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
+ *  Copyright (C) 2004 IBM Inc.
+ *
+ *  debugfs is for people to use instead of /proc or /sys.
+ *  See Documentation/filesystems/ for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/pagemap.h>
+#include <linux/debugfs.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/atomic.h>
+#include <linux/device.h>
+#include <linux/pm_runtime.h>
+#include <linux/poll.h>
+#include <linux/security.h>
+
+#include "internal.h"
+
+struct poll_table_struct;
+
+static ssize_t default_read_file(struct file *file, char __user *buf,
+				 size_t count, loff_t *ppos)
+{
+	return 0;
+}
+
+static ssize_t default_write_file(struct file *file, const char __user *buf,
+				   size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+const struct file_operations debugfs_noop_file_operations = {
+	.read =		default_read_file,
+	.write =	default_write_file,
+	.open =		simple_open,
+	.llseek =	noop_llseek,
+};
+
+#define F_DENTRY(filp) ((filp)->f_path.dentry)
+
+void *debugfs_get_aux(const struct file *file)
+{
+	return DEBUGFS_I(file_inode(file))->aux;
+}
+EXPORT_SYMBOL_GPL(debugfs_get_aux);
+
+enum dbgfs_get_mode {
+	DBGFS_GET_ALREADY,
+	DBGFS_GET_REGULAR,
+	DBGFS_GET_SHORT,
+};
+
+static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
+{
+	struct debugfs_fsdata *fsd;
+	void *d_fsd;
+
+	/*
+	 * This could only happen if some debugfs user erroneously calls
+	 * debugfs_file_get() on a dentry that isn't even a file, let
+	 * them know about it.
+	 */
+	if (WARN_ON(!d_is_reg(dentry)))
+		return -EINVAL;
+
+	d_fsd = READ_ONCE(dentry->d_fsdata);
+	if (d_fsd) {
+		fsd = d_fsd;
+	} else {
+		struct inode *inode = dentry->d_inode;
+		unsigned int methods = 0;
+
+		if (WARN_ON(mode == DBGFS_GET_ALREADY))
+			return -EINVAL;
+
+		fsd = kmalloc_obj(*fsd);
+		if (!fsd)
+			return -ENOMEM;
+
+		if (mode == DBGFS_GET_SHORT) {
+			const struct debugfs_short_fops *ops;
+			ops = fsd->short_fops = DEBUGFS_I(inode)->short_fops;
+			if (ops->llseek)
+				methods |= HAS_LSEEK;
+			if (ops->read)
+				methods |= HAS_READ;
+			if (ops->write)
+				methods |= HAS_WRITE;
+			fsd->real_fops = NULL;
+		} else {
+			const struct file_operations *ops;
+			ops = fsd->real_fops = DEBUGFS_I(inode)->real_fops;
+			if (ops->llseek)
+				methods |= HAS_LSEEK;
+			if (ops->read)
+				methods |= HAS_READ;
+			if (ops->write)
+				methods |= HAS_WRITE;
+			if (ops->unlocked_ioctl)
+				methods |= HAS_IOCTL;
+			if (ops->poll)
+				methods |= HAS_POLL;
+			fsd->short_fops = NULL;
+		}
+		fsd->methods = methods;
+		refcount_set(&fsd->active_users, 1);
+		init_completion(&fsd->active_users_drained);
+		INIT_LIST_HEAD(&fsd->cancellations);
+		mutex_init(&fsd->cancellations_mtx);
+
+		d_fsd = cmpxchg(&dentry->d_fsdata, NULL, fsd);
+		if (d_fsd) {
+			mutex_destroy(&fsd->cancellations_mtx);
+			kfree(fsd);
+			fsd = d_fsd;
+		}
+	}
+
+	/*
+	 * In case of a successful cmpxchg() above, this check is
+	 * strictly necessary and must follow it, see the comment in
+	 * __debugfs_remove_file().
+	 * OTOH, if the cmpxchg() hasn't been executed or wasn't
+	 * successful, this serves the purpose of not starving
+	 * removers.
+	 */
+	if (d_unlinked(dentry))
+		return -EIO;
+
+	if (!refcount_inc_not_zero(&fsd->active_users))
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * debugfs_file_get - mark the beginning of file data access
+ * @dentry: the dentry object whose data is being accessed.
+ *
+ * Up to a matching call to debugfs_file_put(), any successive call
+ * into the file removing functions debugfs_remove() and
+ * debugfs_remove_recursive() will block. Since associated private
+ * file data may only get freed after a successful return of any of
+ * the removal functions, you may safely access it after a successful
+ * call to debugfs_file_get() without worrying about lifetime issues.
+ *
+ * If -%EIO is returned, the file has already been removed and thus,
+ * it is not safe to access any of its data. If, on the other hand,
+ * it is allowed to access the file data, zero is returned.
+ */
+int debugfs_file_get(struct dentry *dentry)
+{
+	return __debugfs_file_get(dentry, DBGFS_GET_ALREADY);
+}
+EXPORT_SYMBOL_GPL(debugfs_file_get);
+
+/**
+ * debugfs_file_put - mark the end of file data access
+ * @dentry: the dentry object formerly passed to
+ *          debugfs_file_get().
+ *
+ * Allow any ongoing concurrent call into debugfs_remove() or
+ * debugfs_remove_recursive() blocked by a former call to
+ * debugfs_file_get() to proceed and return to its caller.
+ */
+void debugfs_file_put(struct dentry *dentry)
+{
+	struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
+
+	if (refcount_dec_and_test(&fsd->active_users))
+		complete(&fsd->active_users_drained);
+}
+EXPORT_SYMBOL_GPL(debugfs_file_put);
+
+/**
+ * debugfs_enter_cancellation - enter a debugfs cancellation
+ * @file: the file being accessed
+ * @cancellation: the cancellation object, the cancel callback
+ *	inside of it must be initialized
+ *
+ * When a debugfs file is removed it needs to wait for all active
+ * operations to complete. However, the operation itself may need
+ * to wait for hardware or completion of some asynchronous process
+ * or similar. As such, it may need to be cancelled to avoid long
+ * waits or even deadlocks.
+ *
+ * This function can be used inside a debugfs handler that may
+ * need to be cancelled. As soon as this function is called, the
+ * cancellation's 'cancel' callback may be called, at which point
+ * the caller should proceed to call debugfs_leave_cancellation()
+ * and leave the debugfs handler function as soon as possible.
+ * Note that the 'cancel' callback is only ever called in the
+ * context of some kind of debugfs_remove().
+ *
+ * This function must be paired with debugfs_leave_cancellation().
+ */
+void debugfs_enter_cancellation(struct file *file,
+				struct debugfs_cancellation *cancellation)
+{
+	struct debugfs_fsdata *fsd;
+	struct dentry *dentry = F_DENTRY(file);
+
+	INIT_LIST_HEAD(&cancellation->list);
+
+	if (WARN_ON(!d_is_reg(dentry)))
+		return;
+
+	if (WARN_ON(!cancellation->cancel))
+		return;
+
+	fsd = READ_ONCE(dentry->d_fsdata);
+	if (WARN_ON(!fsd))
+		return;
+
+	mutex_lock(&fsd->cancellations_mtx);
+	list_add(&cancellation->list, &fsd->cancellations);
+	mutex_unlock(&fsd->cancellations_mtx);
+
+	/* if we're already removing wake it up to cancel */
+	if (d_unlinked(dentry))
+		complete(&fsd->active_users_drained);
+}
+EXPORT_SYMBOL_GPL(debugfs_enter_cancellation);
+
+/**
+ * debugfs_leave_cancellation - leave cancellation section
+ * @file: the file being accessed
+ * @cancellation: the cancellation previously registered with
+ *	debugfs_enter_cancellation()
+ *
+ * See the documentation of debugfs_enter_cancellation().
+ */
+void debugfs_leave_cancellation(struct file *file,
+				struct debugfs_cancellation *cancellation)
+{
+	struct debugfs_fsdata *fsd;
+	struct dentry *dentry = F_DENTRY(file);
+
+	if (WARN_ON(!d_is_reg(dentry)))
+		return;
+
+	fsd = READ_ONCE(dentry->d_fsdata);
+	if (WARN_ON(!fsd))
+		return;
+
+	mutex_lock(&fsd->cancellations_mtx);
+	if (!list_empty(&cancellation->list))
+		list_del(&cancellation->list);
+	mutex_unlock(&fsd->cancellations_mtx);
+}
+EXPORT_SYMBOL_GPL(debugfs_leave_cancellation);
+
+/*
+ * Only permit access to world-readable files when the kernel is locked down.
+ * We also need to exclude any file that has ways to write or alter it as root
+ * can bypass the permissions check.
+ */
+static int debugfs_locked_down(struct inode *inode,
+			       struct file *filp,
+			       const struct file_operations *real_fops)
+{
+	if ((inode->i_mode & 07777 & ~0444) == 0 &&
+	    !(filp->f_mode & FMODE_WRITE) &&
+	    (!real_fops ||
+	     (!real_fops->unlocked_ioctl &&
+	      !real_fops->compat_ioctl &&
+	      !real_fops->mmap &&
+	      !real_fops->mmap_prepare)))
+		return 0;
+
+	if (security_locked_down(LOCKDOWN_DEBUGFS))
+		return -EPERM;
+
+	return 0;
+}
+
+static int open_proxy_open(struct inode *inode, struct file *filp)
+{
+	struct dentry *dentry = F_DENTRY(filp);
+	const struct file_operations *real_fops = DEBUGFS_I(inode)->real_fops;
+	int r;
+
+	r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR);
+	if (r)
+		return r == -EIO ? -ENOENT : r;
+
+	r = debugfs_locked_down(inode, filp, real_fops);
+	if (r)
+		goto out;
+
+	if (!fops_get(real_fops)) {
+#ifdef CONFIG_MODULES
+		if (real_fops->owner &&
+		    real_fops->owner->state == MODULE_STATE_GOING) {
+			r = -ENXIO;
+			goto out;
+		}
+#endif
+
+		/* Huh? Module did not clean up after itself at exit? */
+		WARN(1, "debugfs file owner did not clean up at exit: %pd",
+			dentry);
+		r = -ENXIO;
+		goto out;
+	}
+	replace_fops(filp, real_fops);
+
+	if (real_fops->open)
+		r = real_fops->open(inode, filp);
+
+out:
+	debugfs_file_put(dentry);
+	return r;
+}
+
+const struct file_operations debugfs_open_proxy_file_operations = {
+	.open = open_proxy_open,
+};
+
+#define PROTO(args...) args
+#define ARGS(args...) args
+
+#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret)	\
+static ret_type full_proxy_ ## name(proto)				\
+{									\
+	struct dentry *dentry = F_DENTRY(filp);				\
+	struct debugfs_fsdata *fsd = dentry->d_fsdata;			\
+	ret_type r;							\
+									\
+	if (!(fsd->methods & bit))					\
+		return ret;						\
+	r = debugfs_file_get(dentry);					\
+	if (unlikely(r))						\
+		return r;						\
+	r = fsd->real_fops->name(args);					\
+	debugfs_file_put(dentry);					\
+	return r;							\
+}
+
+#define SHORT_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret)	\
+static ret_type short_proxy_ ## name(proto)				\
+{									\
+	struct dentry *dentry = F_DENTRY(filp);				\
+	struct debugfs_fsdata *fsd = dentry->d_fsdata;			\
+	ret_type r;							\
+									\
+	if (!(fsd->methods & bit))					\
+		return ret;						\
+	r = debugfs_file_get(dentry);					\
+	if (unlikely(r))						\
+		return r;						\
+	r = fsd->short_fops->name(args);				\
+	debugfs_file_put(dentry);					\
+	return r;							\
+}
+
+SHORT_PROXY_FUNC(llseek, loff_t, filp,
+		PROTO(struct file *filp, loff_t offset, int whence),
+		ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
+
+FULL_PROXY_FUNC(llseek, loff_t, filp,
+		PROTO(struct file *filp, loff_t offset, int whence),
+		ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
+
+SHORT_PROXY_FUNC(read, ssize_t, filp,
+		PROTO(struct file *filp, char __user *buf, size_t size,
+			loff_t *ppos),
+		ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
+
+FULL_PROXY_FUNC(read, ssize_t, filp,
+		PROTO(struct file *filp, char __user *buf, size_t size,
+			loff_t *ppos),
+		ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
+
+SHORT_PROXY_FUNC(write, ssize_t, filp,
+		PROTO(struct file *filp, const char __user *buf,
+			size_t size, loff_t *ppos),
+		ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
+
+FULL_PROXY_FUNC(write, ssize_t, filp,
+		PROTO(struct file *filp, const char __user *buf,
+			size_t size, loff_t *ppos),
+		ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
+
+FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
+		PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
+		ARGS(filp, cmd, arg), HAS_IOCTL, -ENOTTY);
+
+static __poll_t full_proxy_poll(struct file *filp,
+				struct poll_table_struct *wait)
+{
+	struct dentry *dentry = F_DENTRY(filp);
+	struct debugfs_fsdata *fsd = dentry->d_fsdata;
+	__poll_t r = 0;
+
+	if (!(fsd->methods & HAS_POLL))
+		return DEFAULT_POLLMASK;
+	if (debugfs_file_get(dentry))
+		return EPOLLHUP;
+
+	r = fsd->real_fops->poll(filp, wait);
+	debugfs_file_put(dentry);
+	return r;
+}
+
+static int full_proxy_release(struct inode *inode, struct file *file)
+{
+	struct debugfs_fsdata *fsd = F_DENTRY(file)->d_fsdata;
+	const struct file_operations *real_fops = fsd->real_fops;
+	int r = 0;
+
+	/*
+	 * We must not protect this against removal races here: the
+	 * original releaser should be called unconditionally in order
+	 * not to leak any resources. Releasers must not assume that
+	 * ->i_private is still being meaningful here.
+	 */
+	if (real_fops->release)
+		r = real_fops->release(inode, file);
+
+	fops_put(real_fops);
+	return r;
+}
+
+static int full_proxy_open_regular(struct inode *inode, struct file *filp)
+{
+	struct dentry *dentry = F_DENTRY(filp);
+	const struct file_operations *real_fops;
+	struct debugfs_fsdata *fsd;
+	int r;
+
+	r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR);
+	if (r)
+		return r == -EIO ? -ENOENT : r;
+
+	fsd = dentry->d_fsdata;
+	real_fops = fsd->real_fops;
+	r = debugfs_locked_down(inode, filp, real_fops);
+	if (r)
+		goto out;
+
+	if (!fops_get(real_fops)) {
+#ifdef CONFIG_MODULES
+		if (real_fops->owner &&
+		    real_fops->owner->state == MODULE_STATE_GOING) {
+			r = -ENXIO;
+			goto out;
+		}
+#endif
+
+		/* Huh? Module did not cleanup after itself at exit? */
+		WARN(1, "debugfs file owner did not clean up at exit: %pd",
+			dentry);
+		r = -ENXIO;
+		goto out;
+	}
+
+	if (real_fops->open) {
+		r = real_fops->open(inode, filp);
+		if (r) {
+			fops_put(real_fops);
+		} else if (filp->f_op != &debugfs_full_proxy_file_operations) {
+			/* No protection against file removal anymore. */
+			WARN(1, "debugfs file owner replaced proxy fops: %pd",
+				dentry);
+			fops_put(real_fops);
+		}
+	}
+out:
+	debugfs_file_put(dentry);
+	return r;
+}
+
+const struct file_operations debugfs_full_proxy_file_operations = {
+	.open = full_proxy_open_regular,
+	.release = full_proxy_release,
+	.llseek = full_proxy_llseek,
+	.read = full_proxy_read,
+	.write = full_proxy_write,
+	.poll = full_proxy_poll,
+	.unlocked_ioctl = full_proxy_unlocked_ioctl
+};
+
+static int full_proxy_open_short(struct inode *inode, struct file *filp)
+{
+	struct dentry *dentry = F_DENTRY(filp);
+	int r;
+
+	r = __debugfs_file_get(dentry, DBGFS_GET_SHORT);
+	if (r)
+		return r == -EIO ? -ENOENT : r;
+	r = debugfs_locked_down(inode, filp, NULL);
+	if (!r)
+		r = simple_open(inode, filp);
+	debugfs_file_put(dentry);
+	return r;
+}
+
+const struct file_operations debugfs_full_short_proxy_file_operations = {
+	.open = full_proxy_open_short,
+	.llseek = short_proxy_llseek,
+	.read = short_proxy_read,
+	.write = short_proxy_write,
+};
+
+ssize_t debugfs_attr_read(struct file *file, char __user *buf,
+			size_t len, loff_t *ppos)
+{
+	struct dentry *dentry = F_DENTRY(file);
+	ssize_t ret;
+
+	ret = debugfs_file_get(dentry);
+	if (unlikely(ret))
+		return ret;
+	ret = simple_attr_read(file, buf, len, ppos);
+	debugfs_file_put(dentry);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(debugfs_attr_read);
+
+static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf,
+			 size_t len, loff_t *ppos, bool is_signed)
+{
+	struct dentry *dentry = F_DENTRY(file);
+	ssize_t ret;
+
+	ret = debugfs_file_get(dentry);
+	if (unlikely(ret))
+		return ret;
+	if (is_signed)
+		ret = simple_attr_write_signed(file, buf, len, ppos);
+	else
+		ret = simple_attr_write(file, buf, len, ppos);
+	debugfs_file_put(dentry);
+	return ret;
+}
+
+ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
+			 size_t len, loff_t *ppos)
+{
+	return debugfs_attr_write_xsigned(file, buf, len, ppos, false);
+}
+EXPORT_SYMBOL_GPL(debugfs_attr_write);
+
+ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
+			 size_t len, loff_t *ppos)
+{
+	return debugfs_attr_write_xsigned(file, buf, len, ppos, true);
+}
+EXPORT_SYMBOL_GPL(debugfs_attr_write_signed);
+
+static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
+					struct dentry *parent, void *value,
+					const struct file_operations *fops,
+					const struct file_operations *fops_ro,
+					const struct file_operations *fops_wo)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file_unsafe(name, mode, parent, value,
+						fops_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file_unsafe(name, mode, parent, value,
+						fops_wo);
+
+	return debugfs_create_file_unsafe(name, mode, parent, value, fops);
+}
+
+static int debugfs_u8_set(void *data, u64 val)
+{
+	*(u8 *)data = val;
+	return 0;
+}
+static int debugfs_u8_get(void *data, u64 *val)
+{
+	*val = *(u8 *)data;
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
+
+/**
+ * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
+		       u8 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
+				   &fops_u8_ro, &fops_u8_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u8);
+
+static int debugfs_u16_set(void *data, u64 val)
+{
+	*(u16 *)data = val;
+	return 0;
+}
+static int debugfs_u16_get(void *data, u64 *val)
+{
+	*val = *(u16 *)data;
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
+
+/**
+ * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
+			u16 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
+				   &fops_u16_ro, &fops_u16_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u16);
+
+static int debugfs_u32_set(void *data, u64 val)
+{
+	*(u32 *)data = val;
+	return 0;
+}
+static int debugfs_u32_get(void *data, u64 *val)
+{
+	*val = *(u32 *)data;
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
+
+/**
+ * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
+			u32 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
+				   &fops_u32_ro, &fops_u32_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u32);
+
+static int debugfs_u64_set(void *data, u64 val)
+{
+	*(u64 *)data = val;
+	return 0;
+}
+
+static int debugfs_u64_get(void *data, u64 *val)
+{
+	*val = *(u64 *)data;
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
+
+/**
+ * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
+			u64 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
+				   &fops_u64_ro, &fops_u64_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u64);
+
+static int debugfs_ulong_set(void *data, u64 val)
+{
+	*(unsigned long *)data = val;
+	return 0;
+}
+
+static int debugfs_ulong_get(void *data, u64 *val)
+{
+	*val = *(unsigned long *)data;
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
+			"%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
+
+/**
+ * debugfs_create_ulong - create a debugfs file that is used to read and write
+ * an unsigned long value.
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
+			  unsigned long *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_ulong,
+				   &fops_ulong_ro, &fops_ulong_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_ulong);
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
+			"0x%04llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
+			"0x%08llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
+			"0x%016llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
+
+/*
+ * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
+ *
+ * These functions are exactly the same as the above functions (but use a hex
+ * output for the decimal challenged). For details look at the above unsigned
+ * decimal functions.
+ */
+
+/**
+ * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
+		       u8 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
+				   &fops_x8_ro, &fops_x8_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x8);
+
+/**
+ * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
+			u16 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
+				   &fops_x16_ro, &fops_x16_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x16);
+
+/**
+ * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
+			u32 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
+				   &fops_x32_ro, &fops_x32_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x32);
+
+/**
+ * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
+			u64 *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
+				   &fops_x64_ro, &fops_x64_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x64);
+
+
+static int debugfs_size_t_set(void *data, u64 val)
+{
+	*(size_t *)data = val;
+	return 0;
+}
+static int debugfs_size_t_get(void *data, u64 *val)
+{
+	*val = *(size_t *)data;
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
+			"%llu\n"); /* %llu and %zu are more or less the same */
+DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
+
+/**
+ * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+void debugfs_create_size_t(const char *name, umode_t mode,
+			   struct dentry *parent, size_t *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
+				   &fops_size_t_ro, &fops_size_t_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_size_t);
+
+static int debugfs_atomic_t_set(void *data, u64 val)
+{
+	atomic_set((atomic_t *)data, val);
+	return 0;
+}
+static int debugfs_atomic_t_get(void *data, u64 *val)
+{
+	*val = atomic_read((atomic_t *)data);
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get,
+			debugfs_atomic_t_set, "%lld\n");
+DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
+			"%lld\n");
+DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
+			"%lld\n");
+
+/**
+ * debugfs_create_atomic_t - create a debugfs file that is used to read and
+ * write an atomic_t value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+void debugfs_create_atomic_t(const char *name, umode_t mode,
+			     struct dentry *parent, atomic_t *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
+				   &fops_atomic_t_ro, &fops_atomic_t_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
+
+ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	char buf[2];
+	bool val;
+	int r;
+	struct dentry *dentry = F_DENTRY(file);
+
+	r = debugfs_file_get(dentry);
+	if (unlikely(r))
+		return r;
+	val = *(bool *)file->private_data;
+	debugfs_file_put(dentry);
+
+	if (val)
+		buf[0] = 'Y';
+	else
+		buf[0] = 'N';
+	buf[1] = '\n';
+	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
+
+ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
+				size_t count, loff_t *ppos)
+{
+	bool bv;
+	int r;
+	bool *val = file->private_data;
+	struct dentry *dentry = F_DENTRY(file);
+
+	r = kstrtobool_from_user(user_buf, count, &bv);
+	if (!r) {
+		r = debugfs_file_get(dentry);
+		if (unlikely(r))
+			return r;
+		*val = bv;
+		debugfs_file_put(dentry);
+	}
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
+
+static const struct file_operations fops_bool = {
+	.read =		debugfs_read_file_bool,
+	.write =	debugfs_write_file_bool,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+static const struct file_operations fops_bool_ro = {
+	.read =		debugfs_read_file_bool,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+static const struct file_operations fops_bool_wo = {
+	.write =	debugfs_write_file_bool,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+/**
+ * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
+			 bool *value)
+{
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
+				   &fops_bool_ro, &fops_bool_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_bool);
+
+ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct dentry *dentry = F_DENTRY(file);
+	char *str, *copy = NULL;
+	int copy_len, len;
+	ssize_t ret;
+
+	ret = debugfs_file_get(dentry);
+	if (unlikely(ret))
+		return ret;
+
+	str = *(char **)file->private_data;
+	len = strlen(str) + 1;
+	copy = kmalloc(len, GFP_KERNEL);
+	if (!copy) {
+		debugfs_file_put(dentry);
+		return -ENOMEM;
+	}
+
+	copy_len = strscpy(copy, str, len);
+	debugfs_file_put(dentry);
+	if (copy_len < 0) {
+		kfree(copy);
+		return copy_len;
+	}
+
+	copy[copy_len] = '\n';
+
+	ret = simple_read_from_buffer(user_buf, count, ppos, copy, len);
+	kfree(copy);
+
+	return ret;
+}
+
+static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	struct dentry *dentry = F_DENTRY(file);
+	char *old, *new = NULL;
+	int pos = *ppos;
+	int r;
+
+	r = debugfs_file_get(dentry);
+	if (unlikely(r))
+		return r;
+
+	old = *(char **)file->private_data;
+
+	/* only allow strict concatenation */
+	r = -EINVAL;
+	if (pos && pos != strlen(old))
+		goto error;
+
+	r = -E2BIG;
+	if (pos + count + 1 > PAGE_SIZE)
+		goto error;
+
+	r = -ENOMEM;
+	new = kmalloc(pos + count + 1, GFP_KERNEL);
+	if (!new)
+		goto error;
+
+	if (pos)
+		memcpy(new, old, pos);
+
+	r = -EFAULT;
+	if (copy_from_user(new + pos, user_buf, count))
+		goto error;
+
+	new[pos + count] = '\0';
+	strim(new);
+
+	rcu_assign_pointer(*(char __rcu **)file->private_data, new);
+	synchronize_rcu();
+	kfree(old);
+
+	debugfs_file_put(dentry);
+	return count;
+
+error:
+	kfree(new);
+	debugfs_file_put(dentry);
+	return r;
+}
+
+static const struct file_operations fops_str = {
+	.read =		debugfs_read_file_str,
+	.write =	debugfs_write_file_str,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+static const struct file_operations fops_str_ro = {
+	.read =		debugfs_read_file_str,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+static const struct file_operations fops_str_wo = {
+	.write =	debugfs_write_file_str,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+/**
+ * debugfs_create_str - create a debugfs file that is used to read and write a string value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from. This pointer and the string it points to must not be %NULL.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ */
+void debugfs_create_str(const char *name, umode_t mode,
+			struct dentry *parent, char **value)
+{
+	if (WARN_ON(!value || !*value))
+		return;
+
+	debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str,
+				   &fops_str_ro, &fops_str_wo);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_str);
+
+static ssize_t read_file_blob(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct debugfs_blob_wrapper *blob = file->private_data;
+	struct dentry *dentry = F_DENTRY(file);
+	ssize_t r;
+
+	r = debugfs_file_get(dentry);
+	if (unlikely(r))
+		return r;
+	r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
+				blob->size);
+	debugfs_file_put(dentry);
+	return r;
+}
+
+static ssize_t write_file_blob(struct file *file, const char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	struct debugfs_blob_wrapper *blob = file->private_data;
+	struct dentry *dentry = F_DENTRY(file);
+	ssize_t r;
+
+	r = debugfs_file_get(dentry);
+	if (unlikely(r))
+		return r;
+	r = simple_write_to_buffer(blob->data, blob->size, ppos, user_buf,
+				   count);
+
+	debugfs_file_put(dentry);
+	return r;
+}
+
+static const struct file_operations fops_blob = {
+	.read =		read_file_blob,
+	.write =	write_file_blob,
+	.open =		simple_open,
+	.llseek =	default_llseek,
+};
+
+/**
+ * debugfs_create_blob - create a debugfs file that is used to read and write
+ * a binary blob
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
+ *        to the blob data and the size of the data.
+ *
+ * This function creates a file in debugfs with the given name that exports
+ * @blob->data as a binary blob. If the @mode variable is so set it can be
+ * read from and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, ERR_PTR(-ERROR) will be
+ * returned.
+ *
+ * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
+ * be returned.
+ */
+struct dentry *debugfs_create_blob(const char *name, umode_t mode,
+				   struct dentry *parent,
+				   struct debugfs_blob_wrapper *blob)
+{
+	return debugfs_create_file_unsafe(name, mode & 0644, parent, blob, &fops_blob);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_blob);
+
+static size_t u32_format_array(char *buf, size_t bufsize,
+			       u32 *array, int array_size)
+{
+	size_t ret = 0;
+
+	while (--array_size >= 0) {
+		size_t len;
+		char term = array_size ? ' ' : '\n';
+
+		len = snprintf(buf, bufsize, "%u%c", *array++, term);
+		ret += len;
+
+		buf += len;
+		bufsize -= len;
+	}
+	return ret;
+}
+
+static int u32_array_open(struct inode *inode, struct file *file)
+{
+	struct debugfs_u32_array *data = inode->i_private;
+	int size, elements = data->n_elements;
+	char *buf;
+
+	/*
+	 * Max size:
+	 *  - 10 digits + ' '/'\n' = 11 bytes per number
+	 *  - terminating NUL character
+	 */
+	size = elements*11;
+	buf = kmalloc(size+1, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	buf[size] = 0;
+
+	file->private_data = buf;
+	u32_format_array(buf, size, data->array, data->n_elements);
+
+	return nonseekable_open(inode, file);
+}
+
+static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
+			      loff_t *ppos)
+{
+	size_t size = strlen(file->private_data);
+
+	return simple_read_from_buffer(buf, len, ppos,
+					file->private_data, size);
+}
+
+static int u32_array_release(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+
+	return 0;
+}
+
+static const struct file_operations u32_array_fops = {
+	.owner	 = THIS_MODULE,
+	.open	 = u32_array_open,
+	.release = u32_array_release,
+	.read	 = u32_array_read,
+};
+
+/**
+ * debugfs_create_u32_array - create a debugfs file that is used to read u32
+ * array.
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @array: wrapper struct containing data pointer and size of the array.
+ *
+ * This function creates a file in debugfs with the given name that exports
+ * @array as data. If the @mode variable is so set it can be read from.
+ * Writing is not supported. Seek within the file is also not supported.
+ * Once array is created its size can not be changed.
+ */
+void debugfs_create_u32_array(const char *name, umode_t mode,
+			      struct dentry *parent,
+			      struct debugfs_u32_array *array)
+{
+	debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
+
+#ifdef CONFIG_HAS_IOMEM
+
+/*
+ * The regset32 stuff is used to print 32-bit registers using the
+ * seq_file utilities. We offer printing a register set in an already-opened
+ * sequential file or create a debugfs file that only prints a regset32.
+ */
+
+/**
+ * debugfs_print_regs32 - use seq_print to describe a set of registers
+ * @s: the seq_file structure being used to generate output
+ * @regs: an array if struct debugfs_reg32 structures
+ * @nregs: the length of the above array
+ * @base: the base address to be used in reading the registers
+ * @prefix: a string to be prefixed to every output line
+ *
+ * This function outputs a text block describing the current values of
+ * some 32-bit hardware registers. It is meant to be used within debugfs
+ * files based on seq_file that need to show registers, intermixed with other
+ * information. The prefix argument may be used to specify a leading string,
+ * because some peripherals have several blocks of identical registers,
+ * for example configuration of dma channels
+ */
+void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
+			  int nregs, void __iomem *base, char *prefix)
+{
+	int i;
+
+	for (i = 0; i < nregs; i++, regs++) {
+		if (prefix)
+			seq_printf(s, "%s", prefix);
+		seq_printf(s, "%s = 0x%08x\n", regs->name,
+			   readl(base + regs->offset));
+		if (seq_has_overflowed(s))
+			break;
+	}
+}
+EXPORT_SYMBOL_GPL(debugfs_print_regs32);
+
+static int debugfs_regset32_show(struct seq_file *s, void *data)
+{
+	struct debugfs_regset32 *regset = s->private;
+
+	if (regset->dev)
+		pm_runtime_get_sync(regset->dev);
+
+	debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
+
+	if (regset->dev)
+		pm_runtime_put(regset->dev);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
+
+/**
+ * debugfs_create_regset32 - create a debugfs file that returns register values
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
+ *          to an array of register definitions, the array size and the base
+ *          address where the register bank is to be found.
+ *
+ * This function creates a file in debugfs with the given name that reports
+ * the names and values of a set of 32-bit registers. If the @mode variable
+ * is so set it can be read from. Writing is not supported.
+ */
+void debugfs_create_regset32(const char *name, umode_t mode,
+			     struct dentry *parent,
+			     struct debugfs_regset32 *regset)
+{
+	debugfs_create_file(name, mode, parent, regset, &debugfs_regset32_fops);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_regset32);
+
+#endif /* CONFIG_HAS_IOMEM */
+
+struct debugfs_devm_entry {
+	int (*read)(struct seq_file *seq, void *data);
+	struct device *dev;
+};
+
+static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
+{
+	struct debugfs_devm_entry *entry = inode->i_private;
+
+	return single_open(f, entry->read, entry->dev);
+}
+
+static const struct file_operations debugfs_devm_entry_ops = {
+	.owner = THIS_MODULE,
+	.open = debugfs_devm_entry_open,
+	.release = single_release,
+	.read = seq_read,
+	.llseek = seq_lseek
+};
+
+/**
+ * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
+ *
+ * @dev: device related to this debugfs file.
+ * @name: name of the debugfs file.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *	directory dentry if set.  If this parameter is %NULL, then the
+ *	file will be created in the root of the debugfs filesystem.
+ * @read_fn: function pointer called to print the seq_file content.
+ */
+void debugfs_create_devm_seqfile(struct device *dev, const char *name,
+				 struct dentry *parent,
+				 int (*read_fn)(struct seq_file *s, void *data))
+{
+	struct debugfs_devm_entry *entry;
+
+	if (IS_ERR(parent))
+		return;
+
+	entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return;
+
+	entry->read = read_fn;
+	entry->dev = dev;
+
+	debugfs_create_file(name, S_IRUGO, parent, entry,
+			    &debugfs_devm_entry_ops);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);