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, 1171 insertions, 0 deletions

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
new file mode 100644
index 000000000..d32fa4b50
--- /dev/null
+++ b/drivers/input/misc/uinput.c
@@ -0,0 +1,1171 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  User level driver support for input subsystem
+ *
+ * Heavily based on evdev.c by Vojtech Pavlik
+ *
+ * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
+ *
+ * Changes/Revisions:
+ *	0.4	01/09/2014 (Benjamin Tissoires <benjamin.tissoires@redhat.com>)
+ *		- add UI_GET_SYSNAME ioctl
+ *	0.3	09/04/2006 (Anssi Hannula <anssi.hannula@gmail.com>)
+ *		- updated ff support for the changes in kernel interface
+ *		- added MODULE_VERSION
+ *	0.2	16/10/2004 (Micah Dowty <micah@navi.cx>)
+ *		- added force feedback support
+ *              - added UI_SET_PHYS
+ *	0.1	20/06/2002
+ *		- first public version
+ */
+#include <uapi/linux/uinput.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/lockdep.h>
+#include <linux/miscdevice.h>
+#include <linux/overflow.h>
+#include <linux/spinlock.h>
+#include <linux/input/mt.h>
+#include "../input-compat.h"
+
+#define UINPUT_NAME		"uinput"
+#define UINPUT_BUFFER_SIZE	16
+#define UINPUT_NUM_REQUESTS	16
+#define UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS 10
+
+enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };
+
+struct uinput_request {
+	unsigned int		id;
+	unsigned int		code;	/* UI_FF_UPLOAD, UI_FF_ERASE */
+
+	int			retval;
+	struct completion	done;
+
+	union {
+		unsigned int	effect_id;
+		struct {
+			struct ff_effect *effect;
+			struct ff_effect *old;
+		} upload;
+	} u;
+};
+
+struct uinput_device {
+	struct input_dev	*dev;
+	struct mutex		mutex;
+	enum uinput_state	state;
+	spinlock_t		state_lock;
+	wait_queue_head_t	waitq;
+	unsigned char		ready;
+	unsigned char		head;
+	unsigned char		tail;
+	struct input_event	buff[UINPUT_BUFFER_SIZE];
+	unsigned int		ff_effects_max;
+
+	struct uinput_request	*requests[UINPUT_NUM_REQUESTS];
+	wait_queue_head_t	requests_waitq;
+	spinlock_t		requests_lock;
+};
+
+static int uinput_dev_event(struct input_dev *dev,
+			    unsigned int type, unsigned int code, int value)
+{
+	struct uinput_device	*udev = input_get_drvdata(dev);
+	struct timespec64	ts;
+
+	lockdep_assert_held(&dev->event_lock);
+
+	ktime_get_ts64(&ts);
+
+	udev->buff[udev->head] = (struct input_event) {
+		.input_event_sec = ts.tv_sec,
+		.input_event_usec = ts.tv_nsec / NSEC_PER_USEC,
+		.type = type,
+		.code = code,
+		.value = value,
+	};
+
+	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
+
+	wake_up_interruptible(&udev->waitq);
+
+	return 0;
+}
+
+/* Atomically allocate an ID for the given request. Returns 0 on success. */
+static bool uinput_request_alloc_id(struct uinput_device *udev,
+				    struct uinput_request *request)
+{
+	unsigned int id;
+	bool reserved = false;
+
+	spin_lock(&udev->requests_lock);
+
+	for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
+		if (!udev->requests[id]) {
+			request->id = id;
+			udev->requests[id] = request;
+			reserved = true;
+			break;
+		}
+	}
+
+	spin_unlock(&udev->requests_lock);
+	return reserved;
+}
+
+static struct uinput_request *uinput_request_find(struct uinput_device *udev,
+						  unsigned int id)
+{
+	/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
+	if (id >= UINPUT_NUM_REQUESTS)
+		return NULL;
+
+	return udev->requests[id];
+}
+
+static int uinput_request_reserve_slot(struct uinput_device *udev,
+				       struct uinput_request *request)
+{
+	/* Allocate slot. If none are available right away, wait. */
+	return wait_event_interruptible(udev->requests_waitq,
+					uinput_request_alloc_id(udev, request));
+}
+
+static void uinput_request_release_slot(struct uinput_device *udev,
+					unsigned int id)
+{
+	/* Mark slot as available */
+	spin_lock(&udev->requests_lock);
+	udev->requests[id] = NULL;
+	spin_unlock(&udev->requests_lock);
+
+	wake_up(&udev->requests_waitq);
+}
+
+static int uinput_request_send(struct uinput_device *udev,
+			       struct uinput_request *request)
+{
+	unsigned long flags;
+	int retval = 0;
+
+	spin_lock(&udev->state_lock);
+
+	if (udev->state != UIST_CREATED) {
+		retval = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * Tell our userspace application about this new request
+	 * by queueing an input event.
+	 */
+	spin_lock_irqsave(&udev->dev->event_lock, flags);
+	uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
+	spin_unlock_irqrestore(&udev->dev->event_lock, flags);
+
+ out:
+	spin_unlock(&udev->state_lock);
+	return retval;
+}
+
+static int uinput_request_submit(struct uinput_device *udev,
+				 struct uinput_request *request)
+{
+	int retval;
+
+	/*
+	 * Initialize completion before allocating the request slot.
+	 * Once the slot is allocated, uinput_flush_requests() may
+	 * complete it at any time, so it must be initialized first.
+	 */
+	init_completion(&request->done);
+
+	retval = uinput_request_reserve_slot(udev, request);
+	if (retval)
+		return retval;
+
+	retval = uinput_request_send(udev, request);
+	if (retval)
+		goto out;
+
+	if (!wait_for_completion_timeout(&request->done, 30 * HZ)) {
+		retval = -ETIMEDOUT;
+		goto out;
+	}
+
+	retval = request->retval;
+
+ out:
+	uinput_request_release_slot(udev, request->id);
+	return retval;
+}
+
+/*
+ * Fail all outstanding requests so handlers don't wait for the userspace
+ * to finish processing them.
+ */
+static void uinput_flush_requests(struct uinput_device *udev)
+{
+	struct uinput_request *request;
+	int i;
+
+	spin_lock(&udev->requests_lock);
+
+	for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
+		request = udev->requests[i];
+		if (request) {
+			request->retval = -ENODEV;
+			complete(&request->done);
+		}
+	}
+
+	spin_unlock(&udev->requests_lock);
+}
+
+static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
+{
+	uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
+}
+
+static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
+{
+	uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
+}
+
+static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
+{
+	return uinput_dev_event(dev, EV_FF, effect_id, value);
+}
+
+static int uinput_dev_upload_effect(struct input_dev *dev,
+				    struct ff_effect *effect,
+				    struct ff_effect *old)
+{
+	struct uinput_device *udev = input_get_drvdata(dev);
+	struct uinput_request request;
+
+	/*
+	 * uinput driver does not currently support periodic effects with
+	 * custom waveform since it does not have a way to pass buffer of
+	 * samples (custom_data) to userspace. If ever there is a device
+	 * supporting custom waveforms we would need to define an additional
+	 * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
+	 */
+	if (effect->type == FF_PERIODIC &&
+			effect->u.periodic.waveform == FF_CUSTOM)
+		return -EINVAL;
+
+	request.code = UI_FF_UPLOAD;
+	request.u.upload.effect = effect;
+	request.u.upload.old = old;
+
+	return uinput_request_submit(udev, &request);
+}
+
+static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
+{
+	struct uinput_device *udev = input_get_drvdata(dev);
+	struct uinput_request request;
+
+	if (!test_bit(EV_FF, dev->evbit))
+		return -ENOSYS;
+
+	request.code = UI_FF_ERASE;
+	request.u.effect_id = effect_id;
+
+	return uinput_request_submit(udev, &request);
+}
+
+static int uinput_dev_flush(struct input_dev *dev, struct file *file)
+{
+	/*
+	 * If we are called with file == NULL that means we are tearing
+	 * down the device, and therefore we can not handle FF erase
+	 * requests: either we are handling UI_DEV_DESTROY (and holding
+	 * the udev->mutex), or the file descriptor is closed and there is
+	 * nobody on the other side anymore.
+	 */
+	return file ? input_ff_flush(dev, file) : 0;
+}
+
+static void uinput_destroy_device(struct uinput_device *udev)
+{
+	const char *name, *phys;
+	struct input_dev *dev = udev->dev;
+	enum uinput_state old_state = udev->state;
+
+	/*
+	 * Update state under state_lock so that concurrent
+	 * uinput_request_send() sees the state change before we
+	 * flush pending requests and tear down the device.
+	 */
+	spin_lock(&udev->state_lock);
+	udev->state = UIST_NEW_DEVICE;
+	spin_unlock(&udev->state_lock);
+
+	if (dev) {
+		name = dev->name;
+		phys = dev->phys;
+		if (old_state == UIST_CREATED) {
+			uinput_flush_requests(udev);
+			input_unregister_device(dev);
+		} else {
+			input_free_device(dev);
+		}
+		kfree(name);
+		kfree(phys);
+		udev->dev = NULL;
+	}
+}
+
+static int uinput_create_device(struct uinput_device *udev)
+{
+	struct input_dev *dev = udev->dev;
+	int error, nslot;
+
+	if (udev->state != UIST_SETUP_COMPLETE) {
+		printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
+		return -EINVAL;
+	}
+
+	if (test_bit(EV_ABS, dev->evbit)) {
+		input_alloc_absinfo(dev);
+		if (!dev->absinfo) {
+			error = -EINVAL;
+			goto fail1;
+		}
+
+		if (test_bit(ABS_MT_SLOT, dev->absbit)) {
+			nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
+			error = input_mt_init_slots(dev, nslot, 0);
+			if (error)
+				goto fail1;
+		} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
+			input_set_events_per_packet(dev, 60);
+		}
+	}
+
+	if (test_bit(EV_FF, dev->evbit) && !udev->ff_effects_max) {
+		printk(KERN_DEBUG "%s: ff_effects_max should be non-zero when FF_BIT is set\n",
+			UINPUT_NAME);
+		error = -EINVAL;
+		goto fail1;
+	}
+
+	if (udev->ff_effects_max) {
+		error = input_ff_create(dev, udev->ff_effects_max);
+		if (error)
+			goto fail1;
+
+		dev->ff->upload = uinput_dev_upload_effect;
+		dev->ff->erase = uinput_dev_erase_effect;
+		dev->ff->playback = uinput_dev_playback;
+		dev->ff->set_gain = uinput_dev_set_gain;
+		dev->ff->set_autocenter = uinput_dev_set_autocenter;
+		/*
+		 * The standard input_ff_flush() implementation does
+		 * not quite work for uinput as we can't reasonably
+		 * handle FF requests during device teardown.
+		 */
+		dev->flush = uinput_dev_flush;
+	}
+
+	dev->event = uinput_dev_event;
+
+	input_set_drvdata(udev->dev, udev);
+
+	error = input_register_device(udev->dev);
+	if (error)
+		goto fail2;
+
+	spin_lock(&udev->state_lock);
+	udev->state = UIST_CREATED;
+	spin_unlock(&udev->state_lock);
+
+	return 0;
+
+ fail2:	input_ff_destroy(dev);
+ fail1: uinput_destroy_device(udev);
+	return error;
+}
+
+static int uinput_open(struct inode *inode, struct file *file)
+{
+	struct uinput_device *newdev;
+
+	newdev = kzalloc_obj(*newdev);
+	if (!newdev)
+		return -ENOMEM;
+
+	mutex_init(&newdev->mutex);
+	spin_lock_init(&newdev->state_lock);
+	spin_lock_init(&newdev->requests_lock);
+	init_waitqueue_head(&newdev->requests_waitq);
+	init_waitqueue_head(&newdev->waitq);
+	newdev->state = UIST_NEW_DEVICE;
+
+	file->private_data = newdev;
+	stream_open(inode, file);
+
+	return 0;
+}
+
+static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,
+				   const struct input_absinfo *abs)
+{
+	int min, max, range;
+
+	min = abs->minimum;
+	max = abs->maximum;
+
+	if ((min != 0 || max != 0) && max < min) {
+		printk(KERN_DEBUG
+		       "%s: invalid abs[%02x] min:%d max:%d\n",
+		       UINPUT_NAME, code, min, max);
+		return -EINVAL;
+	}
+
+	if (!check_sub_overflow(max, min, &range) && abs->flat > range) {
+		printk(KERN_DEBUG
+		       "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n",
+		       UINPUT_NAME, code, abs->flat, min, max);
+		return -EINVAL;
+	}
+
+	/*
+	 * Limit number of contacts to a reasonable value (100). This
+	 * ensures that we need less than 2 pages for struct input_mt
+	 * (we are not using in-kernel slot assignment so not going to
+	 * allocate memory for the "red" table), and we should have no
+	 * trouble getting this much memory.
+	 */
+	if (code == ABS_MT_SLOT && max > 99) {
+		printk(KERN_DEBUG
+		       "%s: unreasonably large number of slots requested: %d\n",
+		       UINPUT_NAME, max);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int uinput_validate_absbits(struct input_dev *dev)
+{
+	unsigned int cnt;
+	int error;
+
+	if (!test_bit(EV_ABS, dev->evbit))
+		return 0;
+
+	/*
+	 * Check if absmin/absmax/absfuzz/absflat are sane.
+	 */
+
+	for_each_set_bit(cnt, dev->absbit, ABS_CNT) {
+		if (!dev->absinfo)
+			return -EINVAL;
+
+		error = uinput_validate_absinfo(dev, cnt, &dev->absinfo[cnt]);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+static int uinput_dev_setup(struct uinput_device *udev,
+			    struct uinput_setup __user *arg)
+{
+	struct uinput_setup setup;
+	struct input_dev *dev;
+
+	if (udev->state == UIST_CREATED)
+		return -EINVAL;
+
+	if (copy_from_user(&setup, arg, sizeof(setup)))
+		return -EFAULT;
+
+	if (!setup.name[0])
+		return -EINVAL;
+
+	dev = udev->dev;
+	dev->id = setup.id;
+	udev->ff_effects_max = setup.ff_effects_max;
+
+	kfree(dev->name);
+	dev->name = kstrndup(setup.name, UINPUT_MAX_NAME_SIZE, GFP_KERNEL);
+	if (!dev->name)
+		return -ENOMEM;
+
+	udev->state = UIST_SETUP_COMPLETE;
+	return 0;
+}
+
+static int uinput_abs_setup(struct uinput_device *udev,
+			    struct uinput_setup __user *arg, size_t size)
+{
+	struct uinput_abs_setup setup = {};
+	struct input_dev *dev;
+	int error;
+
+	if (size > sizeof(setup))
+		return -E2BIG;
+
+	if (udev->state == UIST_CREATED)
+		return -EINVAL;
+
+	if (copy_from_user(&setup, arg, size))
+		return -EFAULT;
+
+	if (setup.code > ABS_MAX)
+		return -ERANGE;
+
+	dev = udev->dev;
+
+	error = uinput_validate_absinfo(dev, setup.code, &setup.absinfo);
+	if (error)
+		return error;
+
+	input_alloc_absinfo(dev);
+	if (!dev->absinfo)
+		return -ENOMEM;
+
+	set_bit(setup.code, dev->absbit);
+	dev->absinfo[setup.code] = setup.absinfo;
+	return 0;
+}
+
+/* legacy setup via write() */
+static int uinput_setup_device_legacy(struct uinput_device *udev,
+				      const char __user *buffer, size_t count)
+{
+	struct uinput_user_dev	*user_dev;
+	struct input_dev	*dev;
+	int			i;
+	int			retval;
+
+	if (count != sizeof(struct uinput_user_dev))
+		return -EINVAL;
+
+	if (!udev->dev) {
+		udev->dev = input_allocate_device();
+		if (!udev->dev)
+			return -ENOMEM;
+	}
+
+	dev = udev->dev;
+
+	user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
+	if (IS_ERR(user_dev))
+		return PTR_ERR(user_dev);
+
+	udev->ff_effects_max = user_dev->ff_effects_max;
+
+	/* Ensure name is filled in */
+	if (!user_dev->name[0]) {
+		retval = -EINVAL;
+		goto exit;
+	}
+
+	kfree(dev->name);
+	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
+			     GFP_KERNEL);
+	if (!dev->name) {
+		retval = -ENOMEM;
+		goto exit;
+	}
+
+	dev->id.bustype	= user_dev->id.bustype;
+	dev->id.vendor	= user_dev->id.vendor;
+	dev->id.product	= user_dev->id.product;
+	dev->id.version	= user_dev->id.version;
+
+	for (i = 0; i < ABS_CNT; i++) {
+		input_abs_set_max(dev, i, user_dev->absmax[i]);
+		input_abs_set_min(dev, i, user_dev->absmin[i]);
+		input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
+		input_abs_set_flat(dev, i, user_dev->absflat[i]);
+	}
+
+	retval = uinput_validate_absbits(dev);
+	if (retval < 0)
+		goto exit;
+
+	udev->state = UIST_SETUP_COMPLETE;
+	retval = count;
+
+ exit:
+	kfree(user_dev);
+	return retval;
+}
+
+/*
+ * Returns true if the given timestamp is valid (i.e., if all the following
+ * conditions are satisfied), false otherwise.
+ * 1) given timestamp is positive
+ * 2) it's within the allowed offset before the current time
+ * 3) it's not in the future
+ */
+static bool is_valid_timestamp(const ktime_t timestamp)
+{
+	ktime_t zero_time;
+	ktime_t current_time;
+	ktime_t min_time;
+	ktime_t offset;
+
+	zero_time = ktime_set(0, 0);
+	if (ktime_compare(zero_time, timestamp) >= 0)
+		return false;
+
+	current_time = ktime_get();
+	offset = ktime_set(UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS, 0);
+	min_time = ktime_sub(current_time, offset);
+
+	if (ktime_after(min_time, timestamp) || ktime_after(timestamp, current_time))
+		return false;
+
+	return true;
+}
+
+static ssize_t uinput_inject_events(struct uinput_device *udev,
+				    const char __user *buffer, size_t count)
+{
+	struct input_event ev;
+	size_t bytes = 0;
+	ktime_t timestamp;
+
+	if (count != 0 && count < input_event_size())
+		return -EINVAL;
+
+	while (bytes + input_event_size() <= count) {
+		/*
+		 * Note that even if some events were fetched successfully
+		 * we are still going to return EFAULT instead of partial
+		 * count to let userspace know that it got it's buffers
+		 * all wrong.
+		 */
+		if (input_event_from_user(buffer + bytes, &ev))
+			return -EFAULT;
+
+		timestamp = ktime_set(ev.input_event_sec, ev.input_event_usec * NSEC_PER_USEC);
+		if (is_valid_timestamp(timestamp))
+			input_set_timestamp(udev->dev, timestamp);
+
+		input_event(udev->dev, ev.type, ev.code, ev.value);
+		bytes += input_event_size();
+		cond_resched();
+	}
+
+	return bytes;
+}
+
+static ssize_t uinput_write(struct file *file, const char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	struct uinput_device *udev = file->private_data;
+	int retval;
+
+	if (count == 0)
+		return 0;
+
+	retval = mutex_lock_interruptible(&udev->mutex);
+	if (retval)
+		return retval;
+
+	retval = udev->state == UIST_CREATED ?
+			uinput_inject_events(udev, buffer, count) :
+			uinput_setup_device_legacy(udev, buffer, count);
+
+	mutex_unlock(&udev->mutex);
+
+	return retval;
+}
+
+static bool uinput_fetch_next_event(struct uinput_device *udev,
+				    struct input_event *event)
+{
+	bool have_event;
+
+	spin_lock_irq(&udev->dev->event_lock);
+
+	have_event = udev->head != udev->tail;
+	if (have_event) {
+		*event = udev->buff[udev->tail];
+		udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
+	}
+
+	spin_unlock_irq(&udev->dev->event_lock);
+
+	return have_event;
+}
+
+static ssize_t uinput_events_to_user(struct uinput_device *udev,
+				     char __user *buffer, size_t count)
+{
+	struct input_event event;
+	size_t read = 0;
+
+	while (read + input_event_size() <= count &&
+	       uinput_fetch_next_event(udev, &event)) {
+
+		if (input_event_to_user(buffer + read, &event))
+			return -EFAULT;
+
+		read += input_event_size();
+	}
+
+	return read;
+}
+
+static ssize_t uinput_read(struct file *file, char __user *buffer,
+			   size_t count, loff_t *ppos)
+{
+	struct uinput_device *udev = file->private_data;
+	ssize_t retval;
+
+	if (count != 0 && count < input_event_size())
+		return -EINVAL;
+
+	do {
+		retval = mutex_lock_interruptible(&udev->mutex);
+		if (retval)
+			return retval;
+
+		if (udev->state != UIST_CREATED)
+			retval = -ENODEV;
+		else if (udev->head == udev->tail &&
+			 (file->f_flags & O_NONBLOCK))
+			retval = -EAGAIN;
+		else
+			retval = uinput_events_to_user(udev, buffer, count);
+
+		mutex_unlock(&udev->mutex);
+
+		if (retval || count == 0)
+			break;
+
+		if (!(file->f_flags & O_NONBLOCK))
+			retval = wait_event_interruptible(udev->waitq,
+						  udev->head != udev->tail ||
+						  udev->state != UIST_CREATED);
+	} while (retval == 0);
+
+	return retval;
+}
+
+static __poll_t uinput_poll(struct file *file, poll_table *wait)
+{
+	struct uinput_device *udev = file->private_data;
+	__poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uinput is always writable */
+
+	poll_wait(file, &udev->waitq, wait);
+
+	if (udev->head != udev->tail)
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	return mask;
+}
+
+static int uinput_release(struct inode *inode, struct file *file)
+{
+	struct uinput_device *udev = file->private_data;
+
+	uinput_destroy_device(udev);
+	kfree(udev);
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+struct uinput_ff_upload_compat {
+	__u32			request_id;
+	__s32			retval;
+	struct ff_effect_compat	effect;
+	struct ff_effect_compat	old;
+};
+
+static int uinput_ff_upload_to_user(char __user *buffer,
+				    const struct uinput_ff_upload *ff_up)
+{
+	if (in_compat_syscall()) {
+		struct uinput_ff_upload_compat ff_up_compat;
+
+		memset(&ff_up_compat, 0, sizeof(ff_up_compat));
+		ff_up_compat.request_id = ff_up->request_id;
+		ff_up_compat.retval = ff_up->retval;
+		/*
+		 * It so happens that the pointer that gives us the trouble
+		 * is the last field in the structure. Since we don't support
+		 * custom waveforms in uinput anyway we can just copy the whole
+		 * thing (to the compat size) and ignore the pointer.
+		 */
+		memcpy(&ff_up_compat.effect, &ff_up->effect,
+			sizeof(struct ff_effect_compat));
+		memcpy(&ff_up_compat.old, &ff_up->old,
+			sizeof(struct ff_effect_compat));
+
+		if (copy_to_user(buffer, &ff_up_compat,
+				 sizeof(struct uinput_ff_upload_compat)))
+			return -EFAULT;
+	} else {
+		if (copy_to_user(buffer, ff_up,
+				 sizeof(struct uinput_ff_upload)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int uinput_ff_upload_from_user(const char __user *buffer,
+				      struct uinput_ff_upload *ff_up)
+{
+	if (in_compat_syscall()) {
+		struct uinput_ff_upload_compat ff_up_compat;
+
+		if (copy_from_user(&ff_up_compat, buffer,
+				   sizeof(struct uinput_ff_upload_compat)))
+			return -EFAULT;
+
+		ff_up->request_id = ff_up_compat.request_id;
+		ff_up->retval = ff_up_compat.retval;
+		memcpy(&ff_up->effect, &ff_up_compat.effect,
+			sizeof(struct ff_effect_compat));
+		memcpy(&ff_up->old, &ff_up_compat.old,
+			sizeof(struct ff_effect_compat));
+
+	} else {
+		if (copy_from_user(ff_up, buffer,
+				   sizeof(struct uinput_ff_upload)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+#else
+
+static int uinput_ff_upload_to_user(char __user *buffer,
+				    const struct uinput_ff_upload *ff_up)
+{
+	if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int uinput_ff_upload_from_user(const char __user *buffer,
+				      struct uinput_ff_upload *ff_up)
+{
+	if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
+		return -EFAULT;
+
+	return 0;
+}
+
+#endif
+
+#define uinput_set_bit(_arg, _bit, _max)		\
+({							\
+	int __ret = 0;					\
+	if (udev->state == UIST_CREATED)		\
+		__ret =  -EINVAL;			\
+	else if ((_arg) > (_max))			\
+		__ret = -EINVAL;			\
+	else set_bit((_arg), udev->dev->_bit);		\
+	__ret;						\
+})
+
+static int uinput_str_to_user(void __user *dest, const char *str,
+			      unsigned int maxlen)
+{
+	char __user *p = dest;
+	int len, ret;
+
+	if (!str)
+		return -ENOENT;
+
+	if (maxlen == 0)
+		return -EINVAL;
+
+	len = strlen(str) + 1;
+	if (len > maxlen)
+		len = maxlen;
+
+	ret = copy_to_user(p, str, len);
+	if (ret)
+		return -EFAULT;
+
+	/* force terminating '\0' */
+	ret = put_user(0, p + len - 1);
+	return ret ? -EFAULT : len;
+}
+
+static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
+				 unsigned long arg, void __user *p)
+{
+	int			retval;
+	struct uinput_device	*udev = file->private_data;
+	struct uinput_ff_upload ff_up;
+	struct uinput_ff_erase  ff_erase;
+	struct uinput_request   *req;
+	char			*phys;
+	const char		*name;
+	unsigned int		size;
+
+	retval = mutex_lock_interruptible(&udev->mutex);
+	if (retval)
+		return retval;
+
+	if (!udev->dev) {
+		udev->dev = input_allocate_device();
+		if (!udev->dev) {
+			retval = -ENOMEM;
+			goto out;
+		}
+	}
+
+	switch (cmd) {
+	case UI_GET_VERSION:
+		if (put_user(UINPUT_VERSION, (unsigned int __user *)p))
+			retval = -EFAULT;
+		goto out;
+
+	case UI_DEV_CREATE:
+		retval = uinput_create_device(udev);
+		goto out;
+
+	case UI_DEV_DESTROY:
+		uinput_destroy_device(udev);
+		goto out;
+
+	case UI_DEV_SETUP:
+		retval = uinput_dev_setup(udev, p);
+		goto out;
+
+	/* UI_ABS_SETUP is handled in the variable size ioctls */
+
+	case UI_SET_EVBIT:
+		retval = uinput_set_bit(arg, evbit, EV_MAX);
+		goto out;
+
+	case UI_SET_KEYBIT:
+		retval = uinput_set_bit(arg, keybit, KEY_MAX);
+		goto out;
+
+	case UI_SET_RELBIT:
+		retval = uinput_set_bit(arg, relbit, REL_MAX);
+		goto out;
+
+	case UI_SET_ABSBIT:
+		retval = uinput_set_bit(arg, absbit, ABS_MAX);
+		goto out;
+
+	case UI_SET_MSCBIT:
+		retval = uinput_set_bit(arg, mscbit, MSC_MAX);
+		goto out;
+
+	case UI_SET_LEDBIT:
+		retval = uinput_set_bit(arg, ledbit, LED_MAX);
+		goto out;
+
+	case UI_SET_SNDBIT:
+		retval = uinput_set_bit(arg, sndbit, SND_MAX);
+		goto out;
+
+	case UI_SET_FFBIT:
+		retval = uinput_set_bit(arg, ffbit, FF_MAX);
+		goto out;
+
+	case UI_SET_SWBIT:
+		retval = uinput_set_bit(arg, swbit, SW_MAX);
+		goto out;
+
+	case UI_SET_PROPBIT:
+		retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
+		goto out;
+
+	case UI_SET_PHYS:
+		if (udev->state == UIST_CREATED) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		phys = strndup_user(p, 1024);
+		if (IS_ERR(phys)) {
+			retval = PTR_ERR(phys);
+			goto out;
+		}
+
+		kfree(udev->dev->phys);
+		udev->dev->phys = phys;
+		goto out;
+
+	case UI_BEGIN_FF_UPLOAD:
+		retval = uinput_ff_upload_from_user(p, &ff_up);
+		if (retval)
+			goto out;
+
+		req = uinput_request_find(udev, ff_up.request_id);
+		if (!req || req->code != UI_FF_UPLOAD ||
+		    !req->u.upload.effect) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		ff_up.retval = 0;
+		ff_up.effect = *req->u.upload.effect;
+		if (req->u.upload.old)
+			ff_up.old = *req->u.upload.old;
+		else
+			memset(&ff_up.old, 0, sizeof(struct ff_effect));
+
+		retval = uinput_ff_upload_to_user(p, &ff_up);
+		goto out;
+
+	case UI_BEGIN_FF_ERASE:
+		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
+			retval = -EFAULT;
+			goto out;
+		}
+
+		req = uinput_request_find(udev, ff_erase.request_id);
+		if (!req || req->code != UI_FF_ERASE) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		ff_erase.retval = 0;
+		ff_erase.effect_id = req->u.effect_id;
+		if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
+			retval = -EFAULT;
+			goto out;
+		}
+
+		goto out;
+
+	case UI_END_FF_UPLOAD:
+		retval = uinput_ff_upload_from_user(p, &ff_up);
+		if (retval)
+			goto out;
+
+		req = uinput_request_find(udev, ff_up.request_id);
+		if (!req || req->code != UI_FF_UPLOAD ||
+		    !req->u.upload.effect) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		req->retval = ff_up.retval;
+		complete(&req->done);
+		goto out;
+
+	case UI_END_FF_ERASE:
+		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
+			retval = -EFAULT;
+			goto out;
+		}
+
+		req = uinput_request_find(udev, ff_erase.request_id);
+		if (!req || req->code != UI_FF_ERASE) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		req->retval = ff_erase.retval;
+		complete(&req->done);
+		goto out;
+	}
+
+	size = _IOC_SIZE(cmd);
+
+	/* Now check variable-length commands */
+	switch (cmd & ~IOCSIZE_MASK) {
+	case UI_GET_SYSNAME(0):
+		if (udev->state != UIST_CREATED) {
+			retval = -ENOENT;
+			goto out;
+		}
+		name = dev_name(&udev->dev->dev);
+		retval = uinput_str_to_user(p, name, size);
+		goto out;
+
+	case UI_ABS_SETUP & ~IOCSIZE_MASK:
+		retval = uinput_abs_setup(udev, p, size);
+		goto out;
+	}
+
+	retval = -EINVAL;
+ out:
+	mutex_unlock(&udev->mutex);
+	return retval;
+}
+
+static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
+}
+
+#ifdef CONFIG_COMPAT
+
+/*
+ * These IOCTLs change their size and thus their numbers between
+ * 32 and 64 bits.
+ */
+#define UI_SET_PHYS_COMPAT		\
+	_IOW(UINPUT_IOCTL_BASE, 108, compat_uptr_t)
+#define UI_BEGIN_FF_UPLOAD_COMPAT	\
+	_IOWR(UINPUT_IOCTL_BASE, 200, struct uinput_ff_upload_compat)
+#define UI_END_FF_UPLOAD_COMPAT		\
+	_IOW(UINPUT_IOCTL_BASE, 201, struct uinput_ff_upload_compat)
+
+static long uinput_compat_ioctl(struct file *file,
+				unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case UI_SET_PHYS_COMPAT:
+		cmd = UI_SET_PHYS;
+		break;
+	case UI_BEGIN_FF_UPLOAD_COMPAT:
+		cmd = UI_BEGIN_FF_UPLOAD;
+		break;
+	case UI_END_FF_UPLOAD_COMPAT:
+		cmd = UI_END_FF_UPLOAD;
+		break;
+	}
+
+	return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations uinput_fops = {
+	.owner		= THIS_MODULE,
+	.open		= uinput_open,
+	.release	= uinput_release,
+	.read		= uinput_read,
+	.write		= uinput_write,
+	.poll		= uinput_poll,
+	.unlocked_ioctl	= uinput_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= uinput_compat_ioctl,
+#endif
+};
+
+static struct miscdevice uinput_misc = {
+	.fops		= &uinput_fops,
+	.minor		= UINPUT_MINOR,
+	.name		= UINPUT_NAME,
+};
+module_misc_device(uinput_misc);
+
+MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
+MODULE_ALIAS("devname:" UINPUT_NAME);
+
+MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
+MODULE_DESCRIPTION("User level driver support for input subsystem");
+MODULE_LICENSE("GPL");