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, 1125 insertions, 0 deletions

diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
new file mode 100644
index 000000000..d5c9b0a09
--- /dev/null
+++ b/drivers/input/mousedev.c
@@ -0,0 +1,1125 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Input driver to ExplorerPS/2 device driver module.
+ *
+ * Copyright (c) 1999-2002 Vojtech Pavlik
+ * Copyright (c) 2004      Dmitry Torokhov
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define MOUSEDEV_MINOR_BASE	32
+#define MOUSEDEV_MINORS		31
+#define MOUSEDEV_MIX		63
+
+#include <linux/bitops.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/random.h>
+#include <linux/major.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/kernel.h>
+
+MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
+MODULE_DESCRIPTION("Mouse (ExplorerPS/2) device interfaces");
+MODULE_LICENSE("GPL");
+
+#ifndef CONFIG_INPUT_MOUSEDEV_SCREEN_X
+#define CONFIG_INPUT_MOUSEDEV_SCREEN_X	1024
+#endif
+#ifndef CONFIG_INPUT_MOUSEDEV_SCREEN_Y
+#define CONFIG_INPUT_MOUSEDEV_SCREEN_Y	768
+#endif
+
+static int xres = CONFIG_INPUT_MOUSEDEV_SCREEN_X;
+module_param(xres, uint, 0644);
+MODULE_PARM_DESC(xres, "Horizontal screen resolution");
+
+static int yres = CONFIG_INPUT_MOUSEDEV_SCREEN_Y;
+module_param(yres, uint, 0644);
+MODULE_PARM_DESC(yres, "Vertical screen resolution");
+
+static unsigned tap_time = 200;
+module_param(tap_time, uint, 0644);
+MODULE_PARM_DESC(tap_time, "Tap time for touchpads in absolute mode (msecs)");
+
+struct mousedev_hw_data {
+	int dx, dy, dz;
+	int x, y;
+	int abs_event;
+	unsigned long buttons;
+};
+
+struct mousedev {
+	int open;
+	struct input_handle handle;
+	wait_queue_head_t wait;
+	struct list_head client_list;
+	spinlock_t client_lock; /* protects client_list */
+	struct mutex mutex;
+	struct device dev;
+	struct cdev cdev;
+	bool exist;
+
+	struct list_head mixdev_node;
+	bool opened_by_mixdev;
+
+	struct mousedev_hw_data packet;
+	unsigned int pkt_count;
+	int old_x[4], old_y[4];
+	int frac_dx, frac_dy;
+	unsigned long touch;
+
+	int (*open_device)(struct mousedev *mousedev);
+	void (*close_device)(struct mousedev *mousedev);
+};
+
+enum mousedev_emul {
+	MOUSEDEV_EMUL_PS2,
+	MOUSEDEV_EMUL_IMPS,
+	MOUSEDEV_EMUL_EXPS
+};
+
+struct mousedev_motion {
+	int dx, dy, dz;
+	unsigned long buttons;
+};
+
+#define PACKET_QUEUE_LEN	16
+struct mousedev_client {
+	struct fasync_struct *fasync;
+	struct mousedev *mousedev;
+	struct list_head node;
+
+	struct mousedev_motion packets[PACKET_QUEUE_LEN];
+	unsigned int head, tail;
+	spinlock_t packet_lock;
+	int pos_x, pos_y;
+
+	u8 ps2[6];
+	unsigned char ready, buffer, bufsiz;
+	unsigned char imexseq, impsseq;
+	enum mousedev_emul mode;
+	unsigned long last_buttons;
+};
+
+#define MOUSEDEV_SEQ_LEN	6
+
+static unsigned char mousedev_imps_seq[] = { 0xf3, 200, 0xf3, 100, 0xf3, 80 };
+static unsigned char mousedev_imex_seq[] = { 0xf3, 200, 0xf3, 200, 0xf3, 80 };
+
+static struct mousedev *mousedev_mix;
+static LIST_HEAD(mousedev_mix_list);
+
+#define fx(i)  (mousedev->old_x[(mousedev->pkt_count - (i)) & 03])
+#define fy(i)  (mousedev->old_y[(mousedev->pkt_count - (i)) & 03])
+
+static void mousedev_touchpad_event(struct input_dev *dev,
+				    struct mousedev *mousedev,
+				    unsigned int code, int value)
+{
+	int size, tmp;
+	enum { FRACTION_DENOM = 128 };
+
+	switch (code) {
+
+	case ABS_X:
+
+		fx(0) = value;
+		if (mousedev->touch && mousedev->pkt_count >= 2) {
+			size = input_abs_get_max(dev, ABS_X) -
+					input_abs_get_min(dev, ABS_X);
+			if (size == 0)
+				size = 256 * 2;
+
+			tmp = ((value - fx(2)) * 256 * FRACTION_DENOM) / size;
+			tmp += mousedev->frac_dx;
+			mousedev->packet.dx = tmp / FRACTION_DENOM;
+			mousedev->frac_dx =
+				tmp - mousedev->packet.dx * FRACTION_DENOM;
+		}
+		break;
+
+	case ABS_Y:
+		fy(0) = value;
+		if (mousedev->touch && mousedev->pkt_count >= 2) {
+			/* use X size for ABS_Y to keep the same scale */
+			size = input_abs_get_max(dev, ABS_X) -
+					input_abs_get_min(dev, ABS_X);
+			if (size == 0)
+				size = 256 * 2;
+
+			tmp = -((value - fy(2)) * 256 * FRACTION_DENOM) / size;
+			tmp += mousedev->frac_dy;
+			mousedev->packet.dy = tmp / FRACTION_DENOM;
+			mousedev->frac_dy = tmp -
+				mousedev->packet.dy * FRACTION_DENOM;
+		}
+		break;
+	}
+}
+
+static void mousedev_abs_event(struct input_dev *dev, struct mousedev *mousedev,
+				unsigned int code, int value)
+{
+	int min, max, size;
+
+	switch (code) {
+
+	case ABS_X:
+		min = input_abs_get_min(dev, ABS_X);
+		max = input_abs_get_max(dev, ABS_X);
+
+		size = max - min;
+		if (size == 0)
+			size = xres ? : 1;
+
+		value = clamp(value, min, max);
+
+		mousedev->packet.x = ((value - min) * xres) / size;
+		mousedev->packet.abs_event = 1;
+		break;
+
+	case ABS_Y:
+		min = input_abs_get_min(dev, ABS_Y);
+		max = input_abs_get_max(dev, ABS_Y);
+
+		size = max - min;
+		if (size == 0)
+			size = yres ? : 1;
+
+		value = clamp(value, min, max);
+
+		mousedev->packet.y = yres - ((value - min) * yres) / size;
+		mousedev->packet.abs_event = 1;
+		break;
+	}
+}
+
+static void mousedev_rel_event(struct mousedev *mousedev,
+				unsigned int code, int value)
+{
+	switch (code) {
+	case REL_X:
+		mousedev->packet.dx += value;
+		break;
+
+	case REL_Y:
+		mousedev->packet.dy -= value;
+		break;
+
+	case REL_WHEEL:
+		mousedev->packet.dz -= value;
+		break;
+	}
+}
+
+static void mousedev_key_event(struct mousedev *mousedev,
+				unsigned int code, int value)
+{
+	int index;
+
+	switch (code) {
+
+	case BTN_TOUCH:
+	case BTN_0:
+	case BTN_LEFT:		index = 0; break;
+
+	case BTN_STYLUS:
+	case BTN_1:
+	case BTN_RIGHT:		index = 1; break;
+
+	case BTN_2:
+	case BTN_FORWARD:
+	case BTN_STYLUS2:
+	case BTN_MIDDLE:	index = 2; break;
+
+	case BTN_3:
+	case BTN_BACK:
+	case BTN_SIDE:		index = 3; break;
+
+	case BTN_4:
+	case BTN_EXTRA:		index = 4; break;
+
+	default:		return;
+	}
+
+	if (value) {
+		set_bit(index, &mousedev->packet.buttons);
+		set_bit(index, &mousedev_mix->packet.buttons);
+	} else {
+		clear_bit(index, &mousedev->packet.buttons);
+		clear_bit(index, &mousedev_mix->packet.buttons);
+	}
+}
+
+static void mousedev_notify_readers(struct mousedev *mousedev,
+				    struct mousedev_hw_data *packet)
+{
+	struct mousedev_client *client;
+	struct mousedev_motion *p;
+	unsigned int new_head;
+	int wake_readers = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(client, &mousedev->client_list, node) {
+
+		/* Just acquire the lock, interrupts already disabled */
+		spin_lock(&client->packet_lock);
+
+		p = &client->packets[client->head];
+		if (client->ready && p->buttons != mousedev->packet.buttons) {
+			new_head = (client->head + 1) % PACKET_QUEUE_LEN;
+			if (new_head != client->tail) {
+				p = &client->packets[client->head = new_head];
+				memset(p, 0, sizeof(struct mousedev_motion));
+			}
+		}
+
+		if (packet->abs_event) {
+			p->dx += packet->x - client->pos_x;
+			p->dy += packet->y - client->pos_y;
+			client->pos_x = packet->x;
+			client->pos_y = packet->y;
+		}
+
+		client->pos_x += packet->dx;
+		client->pos_x = clamp_val(client->pos_x, 0, xres);
+
+		client->pos_y += packet->dy;
+		client->pos_y = clamp_val(client->pos_y, 0, yres);
+
+		p->dx += packet->dx;
+		p->dy += packet->dy;
+		p->dz += packet->dz;
+		p->buttons = mousedev->packet.buttons;
+
+		if (p->dx || p->dy || p->dz ||
+		    p->buttons != client->last_buttons)
+			client->ready = 1;
+
+		spin_unlock(&client->packet_lock);
+
+		if (client->ready) {
+			kill_fasync(&client->fasync, SIGIO, POLL_IN);
+			wake_readers = 1;
+		}
+	}
+	rcu_read_unlock();
+
+	if (wake_readers)
+		wake_up_interruptible(&mousedev->wait);
+}
+
+static void mousedev_touchpad_touch(struct mousedev *mousedev, int value)
+{
+	if (!value) {
+		if (mousedev->touch &&
+		    time_before(jiffies,
+				mousedev->touch + msecs_to_jiffies(tap_time))) {
+			/*
+			 * Toggle left button to emulate tap.
+			 * We rely on the fact that mousedev_mix always has 0
+			 * motion packet so we won't mess current position.
+			 */
+			set_bit(0, &mousedev->packet.buttons);
+			set_bit(0, &mousedev_mix->packet.buttons);
+			mousedev_notify_readers(mousedev, &mousedev_mix->packet);
+			mousedev_notify_readers(mousedev_mix,
+						&mousedev_mix->packet);
+			clear_bit(0, &mousedev->packet.buttons);
+			clear_bit(0, &mousedev_mix->packet.buttons);
+		}
+		mousedev->touch = mousedev->pkt_count = 0;
+		mousedev->frac_dx = 0;
+		mousedev->frac_dy = 0;
+
+	} else if (!mousedev->touch)
+		mousedev->touch = jiffies;
+}
+
+static void mousedev_event(struct input_handle *handle,
+			   unsigned int type, unsigned int code, int value)
+{
+	struct mousedev *mousedev = handle->private;
+
+	switch (type) {
+
+	case EV_ABS:
+		/* Ignore joysticks */
+		if (test_bit(BTN_TRIGGER, handle->dev->keybit))
+			return;
+
+		if (test_bit(BTN_TOOL_FINGER, handle->dev->keybit))
+			mousedev_touchpad_event(handle->dev,
+						mousedev, code, value);
+		else
+			mousedev_abs_event(handle->dev, mousedev, code, value);
+
+		break;
+
+	case EV_REL:
+		mousedev_rel_event(mousedev, code, value);
+		break;
+
+	case EV_KEY:
+		if (value != 2) {
+			if (code == BTN_TOUCH &&
+			    test_bit(BTN_TOOL_FINGER, handle->dev->keybit))
+				mousedev_touchpad_touch(mousedev, value);
+			else
+				mousedev_key_event(mousedev, code, value);
+		}
+		break;
+
+	case EV_SYN:
+		if (code == SYN_REPORT) {
+			if (mousedev->touch) {
+				mousedev->pkt_count++;
+				/*
+				 * Input system eats duplicate events,
+				 * but we need all of them to do correct
+				 * averaging so apply present one forward
+				 */
+				fx(0) = fx(1);
+				fy(0) = fy(1);
+			}
+
+			mousedev_notify_readers(mousedev, &mousedev->packet);
+			mousedev_notify_readers(mousedev_mix, &mousedev->packet);
+
+			mousedev->packet.dx = mousedev->packet.dy =
+				mousedev->packet.dz = 0;
+			mousedev->packet.abs_event = 0;
+		}
+		break;
+	}
+}
+
+static int mousedev_fasync(int fd, struct file *file, int on)
+{
+	struct mousedev_client *client = file->private_data;
+
+	return fasync_helper(fd, file, on, &client->fasync);
+}
+
+static void mousedev_free(struct device *dev)
+{
+	struct mousedev *mousedev = container_of(dev, struct mousedev, dev);
+
+	input_put_device(mousedev->handle.dev);
+	kfree(mousedev);
+}
+
+static int mousedev_open_device(struct mousedev *mousedev)
+{
+	int retval;
+
+	retval = mutex_lock_interruptible(&mousedev->mutex);
+	if (retval)
+		return retval;
+
+	if (!mousedev->exist)
+		retval = -ENODEV;
+	else if (!mousedev->open++) {
+		retval = input_open_device(&mousedev->handle);
+		if (retval)
+			mousedev->open--;
+	}
+
+	mutex_unlock(&mousedev->mutex);
+	return retval;
+}
+
+static void mousedev_close_device(struct mousedev *mousedev)
+{
+	mutex_lock(&mousedev->mutex);
+
+	if (mousedev->exist && !--mousedev->open)
+		input_close_device(&mousedev->handle);
+
+	mutex_unlock(&mousedev->mutex);
+}
+
+/*
+ * Open all available devices so they can all be multiplexed in one.
+ * stream. Note that this function is called with mousedev_mix->mutex
+ * held.
+ */
+static int mixdev_open_devices(struct mousedev *mixdev)
+{
+	int error;
+
+	error = mutex_lock_interruptible(&mixdev->mutex);
+	if (error)
+		return error;
+
+	if (!mixdev->open++) {
+		struct mousedev *mousedev;
+
+		list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
+			if (!mousedev->opened_by_mixdev) {
+				if (mousedev_open_device(mousedev))
+					continue;
+
+				mousedev->opened_by_mixdev = true;
+			}
+		}
+	}
+
+	mutex_unlock(&mixdev->mutex);
+	return 0;
+}
+
+/*
+ * Close all devices that were opened as part of multiplexed
+ * device. Note that this function is called with mousedev_mix->mutex
+ * held.
+ */
+static void mixdev_close_devices(struct mousedev *mixdev)
+{
+	mutex_lock(&mixdev->mutex);
+
+	if (!--mixdev->open) {
+		struct mousedev *mousedev;
+
+		list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
+			if (mousedev->opened_by_mixdev) {
+				mousedev->opened_by_mixdev = false;
+				mousedev_close_device(mousedev);
+			}
+		}
+	}
+
+	mutex_unlock(&mixdev->mutex);
+}
+
+
+static void mousedev_attach_client(struct mousedev *mousedev,
+				   struct mousedev_client *client)
+{
+	spin_lock(&mousedev->client_lock);
+	list_add_tail_rcu(&client->node, &mousedev->client_list);
+	spin_unlock(&mousedev->client_lock);
+}
+
+static void mousedev_detach_client(struct mousedev *mousedev,
+				   struct mousedev_client *client)
+{
+	spin_lock(&mousedev->client_lock);
+	list_del_rcu(&client->node);
+	spin_unlock(&mousedev->client_lock);
+	synchronize_rcu();
+}
+
+static int mousedev_release(struct inode *inode, struct file *file)
+{
+	struct mousedev_client *client = file->private_data;
+	struct mousedev *mousedev = client->mousedev;
+
+	mousedev_detach_client(mousedev, client);
+	kfree(client);
+
+	mousedev->close_device(mousedev);
+
+	return 0;
+}
+
+static int mousedev_open(struct inode *inode, struct file *file)
+{
+	struct mousedev_client *client;
+	struct mousedev *mousedev;
+	int error;
+
+#ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
+	if (imajor(inode) == MISC_MAJOR)
+		mousedev = mousedev_mix;
+	else
+#endif
+		mousedev = container_of(inode->i_cdev, struct mousedev, cdev);
+
+	client = kzalloc_obj(struct mousedev_client);
+	if (!client)
+		return -ENOMEM;
+
+	spin_lock_init(&client->packet_lock);
+	client->pos_x = xres / 2;
+	client->pos_y = yres / 2;
+	client->mousedev = mousedev;
+	mousedev_attach_client(mousedev, client);
+
+	error = mousedev->open_device(mousedev);
+	if (error)
+		goto err_free_client;
+
+	file->private_data = client;
+	stream_open(inode, file);
+
+	return 0;
+
+ err_free_client:
+	mousedev_detach_client(mousedev, client);
+	kfree(client);
+	return error;
+}
+
+static void mousedev_packet(struct mousedev_client *client, u8 *ps2_data)
+{
+	struct mousedev_motion *p = &client->packets[client->tail];
+	s8 dx, dy, dz;
+
+	dx = clamp_val(p->dx, -127, 127);
+	p->dx -= dx;
+
+	dy = clamp_val(p->dy, -127, 127);
+	p->dy -= dy;
+
+	ps2_data[0] = BIT(3);
+	ps2_data[0] |= ((dx & BIT(7)) >> 3) | ((dy & BIT(7)) >> 2);
+	ps2_data[0] |= p->buttons & 0x07;
+	ps2_data[1] = dx;
+	ps2_data[2] = dy;
+
+	switch (client->mode) {
+	case MOUSEDEV_EMUL_EXPS:
+		dz = clamp_val(p->dz, -7, 7);
+		p->dz -= dz;
+
+		ps2_data[3] = (dz & 0x0f) | ((p->buttons & 0x18) << 1);
+		client->bufsiz = 4;
+		break;
+
+	case MOUSEDEV_EMUL_IMPS:
+		dz = clamp_val(p->dz, -127, 127);
+		p->dz -= dz;
+
+		ps2_data[0] |= ((p->buttons & 0x10) >> 3) |
+			       ((p->buttons & 0x08) >> 1);
+		ps2_data[3] = dz;
+
+		client->bufsiz = 4;
+		break;
+
+	case MOUSEDEV_EMUL_PS2:
+	default:
+		p->dz = 0;
+
+		ps2_data[0] |= ((p->buttons & 0x10) >> 3) |
+			       ((p->buttons & 0x08) >> 1);
+
+		client->bufsiz = 3;
+		break;
+	}
+
+	if (!p->dx && !p->dy && !p->dz) {
+		if (client->tail == client->head) {
+			client->ready = 0;
+			client->last_buttons = p->buttons;
+		} else
+			client->tail = (client->tail + 1) % PACKET_QUEUE_LEN;
+	}
+}
+
+static void mousedev_generate_response(struct mousedev_client *client,
+					int command)
+{
+	client->ps2[0] = 0xfa; /* ACK */
+
+	switch (command) {
+
+	case 0xeb: /* Poll */
+		mousedev_packet(client, &client->ps2[1]);
+		client->bufsiz++; /* account for leading ACK */
+		break;
+
+	case 0xf2: /* Get ID */
+		switch (client->mode) {
+		case MOUSEDEV_EMUL_PS2:
+			client->ps2[1] = 0;
+			break;
+		case MOUSEDEV_EMUL_IMPS:
+			client->ps2[1] = 3;
+			break;
+		case MOUSEDEV_EMUL_EXPS:
+			client->ps2[1] = 4;
+			break;
+		}
+		client->bufsiz = 2;
+		break;
+
+	case 0xe9: /* Get info */
+		client->ps2[1] = 0x60; client->ps2[2] = 3; client->ps2[3] = 200;
+		client->bufsiz = 4;
+		break;
+
+	case 0xff: /* Reset */
+		client->impsseq = client->imexseq = 0;
+		client->mode = MOUSEDEV_EMUL_PS2;
+		client->ps2[1] = 0xaa; client->ps2[2] = 0x00;
+		client->bufsiz = 3;
+		break;
+
+	default:
+		client->bufsiz = 1;
+		break;
+	}
+	client->buffer = client->bufsiz;
+}
+
+static ssize_t mousedev_write(struct file *file, const char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	struct mousedev_client *client = file->private_data;
+	unsigned char c;
+	unsigned int i;
+
+	for (i = 0; i < count; i++) {
+
+		if (get_user(c, buffer + i))
+			return -EFAULT;
+
+		spin_lock_irq(&client->packet_lock);
+
+		if (c == mousedev_imex_seq[client->imexseq]) {
+			if (++client->imexseq == MOUSEDEV_SEQ_LEN) {
+				client->imexseq = 0;
+				client->mode = MOUSEDEV_EMUL_EXPS;
+			}
+		} else
+			client->imexseq = 0;
+
+		if (c == mousedev_imps_seq[client->impsseq]) {
+			if (++client->impsseq == MOUSEDEV_SEQ_LEN) {
+				client->impsseq = 0;
+				client->mode = MOUSEDEV_EMUL_IMPS;
+			}
+		} else
+			client->impsseq = 0;
+
+		mousedev_generate_response(client, c);
+
+		spin_unlock_irq(&client->packet_lock);
+		cond_resched();
+	}
+
+	kill_fasync(&client->fasync, SIGIO, POLL_IN);
+	wake_up_interruptible(&client->mousedev->wait);
+
+	return count;
+}
+
+static ssize_t mousedev_read(struct file *file, char __user *buffer,
+			     size_t count, loff_t *ppos)
+{
+	struct mousedev_client *client = file->private_data;
+	struct mousedev *mousedev = client->mousedev;
+	u8 data[sizeof(client->ps2)];
+	int retval = 0;
+
+	if (!client->ready && !client->buffer && mousedev->exist &&
+	    (file->f_flags & O_NONBLOCK))
+		return -EAGAIN;
+
+	retval = wait_event_interruptible(mousedev->wait,
+			!mousedev->exist || client->ready || client->buffer);
+	if (retval)
+		return retval;
+
+	if (!mousedev->exist)
+		return -ENODEV;
+
+	spin_lock_irq(&client->packet_lock);
+
+	if (!client->buffer && client->ready) {
+		mousedev_packet(client, client->ps2);
+		client->buffer = client->bufsiz;
+	}
+
+	if (count > client->buffer)
+		count = client->buffer;
+
+	memcpy(data, client->ps2 + client->bufsiz - client->buffer, count);
+	client->buffer -= count;
+
+	spin_unlock_irq(&client->packet_lock);
+
+	if (copy_to_user(buffer, data, count))
+		return -EFAULT;
+
+	return count;
+}
+
+/* No kernel lock - fine */
+static __poll_t mousedev_poll(struct file *file, poll_table *wait)
+{
+	struct mousedev_client *client = file->private_data;
+	struct mousedev *mousedev = client->mousedev;
+	__poll_t mask;
+
+	poll_wait(file, &mousedev->wait, wait);
+
+	mask = mousedev->exist ? EPOLLOUT | EPOLLWRNORM : EPOLLHUP | EPOLLERR;
+	if (client->ready || client->buffer)
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	return mask;
+}
+
+static const struct file_operations mousedev_fops = {
+	.owner		= THIS_MODULE,
+	.read		= mousedev_read,
+	.write		= mousedev_write,
+	.poll		= mousedev_poll,
+	.open		= mousedev_open,
+	.release	= mousedev_release,
+	.fasync		= mousedev_fasync,
+	.llseek		= noop_llseek,
+};
+
+/*
+ * Mark device non-existent. This disables writes, ioctls and
+ * prevents new users from opening the device. Already posted
+ * blocking reads will stay, however new ones will fail.
+ */
+static void mousedev_mark_dead(struct mousedev *mousedev)
+{
+	mutex_lock(&mousedev->mutex);
+	mousedev->exist = false;
+	mutex_unlock(&mousedev->mutex);
+}
+
+/*
+ * Wake up users waiting for IO so they can disconnect from
+ * dead device.
+ */
+static void mousedev_hangup(struct mousedev *mousedev)
+{
+	struct mousedev_client *client;
+
+	spin_lock(&mousedev->client_lock);
+	list_for_each_entry(client, &mousedev->client_list, node)
+		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+	spin_unlock(&mousedev->client_lock);
+
+	wake_up_interruptible(&mousedev->wait);
+}
+
+static void mousedev_cleanup(struct mousedev *mousedev)
+{
+	struct input_handle *handle = &mousedev->handle;
+
+	mousedev_mark_dead(mousedev);
+	mousedev_hangup(mousedev);
+
+	/* mousedev is marked dead so no one else accesses mousedev->open */
+	if (mousedev->open)
+		input_close_device(handle);
+}
+
+static int mousedev_reserve_minor(bool mixdev)
+{
+	int minor;
+
+	if (mixdev) {
+		minor = input_get_new_minor(MOUSEDEV_MIX, 1, false);
+		if (minor < 0)
+			pr_err("failed to reserve mixdev minor: %d\n", minor);
+	} else {
+		minor = input_get_new_minor(MOUSEDEV_MINOR_BASE,
+					    MOUSEDEV_MINORS, true);
+		if (minor < 0)
+			pr_err("failed to reserve new minor: %d\n", minor);
+	}
+
+	return minor;
+}
+
+static struct mousedev *mousedev_create(struct input_dev *dev,
+					struct input_handler *handler,
+					bool mixdev)
+{
+	struct mousedev *mousedev;
+	int minor;
+	int error;
+
+	minor = mousedev_reserve_minor(mixdev);
+	if (minor < 0) {
+		error = minor;
+		goto err_out;
+	}
+
+	mousedev = kzalloc_obj(struct mousedev);
+	if (!mousedev) {
+		error = -ENOMEM;
+		goto err_free_minor;
+	}
+
+	INIT_LIST_HEAD(&mousedev->client_list);
+	INIT_LIST_HEAD(&mousedev->mixdev_node);
+	spin_lock_init(&mousedev->client_lock);
+	mutex_init(&mousedev->mutex);
+	lockdep_set_subclass(&mousedev->mutex,
+			     mixdev ? SINGLE_DEPTH_NESTING : 0);
+	init_waitqueue_head(&mousedev->wait);
+
+	if (mixdev) {
+		dev_set_name(&mousedev->dev, "mice");
+
+		mousedev->open_device = mixdev_open_devices;
+		mousedev->close_device = mixdev_close_devices;
+	} else {
+		int dev_no = minor;
+		/* Normalize device number if it falls into legacy range */
+		if (dev_no < MOUSEDEV_MINOR_BASE + MOUSEDEV_MINORS)
+			dev_no -= MOUSEDEV_MINOR_BASE;
+		dev_set_name(&mousedev->dev, "mouse%d", dev_no);
+
+		mousedev->open_device = mousedev_open_device;
+		mousedev->close_device = mousedev_close_device;
+	}
+
+	mousedev->exist = true;
+	mousedev->handle.dev = input_get_device(dev);
+	mousedev->handle.name = dev_name(&mousedev->dev);
+	mousedev->handle.handler = handler;
+	mousedev->handle.private = mousedev;
+
+	mousedev->dev.class = &input_class;
+	if (dev)
+		mousedev->dev.parent = &dev->dev;
+	mousedev->dev.devt = MKDEV(INPUT_MAJOR, minor);
+	mousedev->dev.release = mousedev_free;
+	device_initialize(&mousedev->dev);
+
+	if (!mixdev) {
+		error = input_register_handle(&mousedev->handle);
+		if (error)
+			goto err_free_mousedev;
+	}
+
+	cdev_init(&mousedev->cdev, &mousedev_fops);
+
+	error = cdev_device_add(&mousedev->cdev, &mousedev->dev);
+	if (error)
+		goto err_cleanup_mousedev;
+
+	return mousedev;
+
+ err_cleanup_mousedev:
+	mousedev_cleanup(mousedev);
+	if (!mixdev)
+		input_unregister_handle(&mousedev->handle);
+ err_free_mousedev:
+	put_device(&mousedev->dev);
+ err_free_minor:
+	input_free_minor(minor);
+ err_out:
+	return ERR_PTR(error);
+}
+
+static void mousedev_destroy(struct mousedev *mousedev)
+{
+	cdev_device_del(&mousedev->cdev, &mousedev->dev);
+	mousedev_cleanup(mousedev);
+	input_free_minor(MINOR(mousedev->dev.devt));
+	if (mousedev != mousedev_mix)
+		input_unregister_handle(&mousedev->handle);
+	put_device(&mousedev->dev);
+}
+
+static int mixdev_add_device(struct mousedev *mousedev)
+{
+	int retval;
+
+	retval = mutex_lock_interruptible(&mousedev_mix->mutex);
+	if (retval)
+		return retval;
+
+	if (mousedev_mix->open) {
+		retval = mousedev_open_device(mousedev);
+		if (retval)
+			goto out;
+
+		mousedev->opened_by_mixdev = true;
+	}
+
+	get_device(&mousedev->dev);
+	list_add_tail(&mousedev->mixdev_node, &mousedev_mix_list);
+
+ out:
+	mutex_unlock(&mousedev_mix->mutex);
+	return retval;
+}
+
+static void mixdev_remove_device(struct mousedev *mousedev)
+{
+	mutex_lock(&mousedev_mix->mutex);
+
+	if (mousedev->opened_by_mixdev) {
+		mousedev->opened_by_mixdev = false;
+		mousedev_close_device(mousedev);
+	}
+
+	list_del_init(&mousedev->mixdev_node);
+	mutex_unlock(&mousedev_mix->mutex);
+
+	put_device(&mousedev->dev);
+}
+
+static int mousedev_connect(struct input_handler *handler,
+			    struct input_dev *dev,
+			    const struct input_device_id *id)
+{
+	struct mousedev *mousedev;
+	int error;
+
+	mousedev = mousedev_create(dev, handler, false);
+	if (IS_ERR(mousedev))
+		return PTR_ERR(mousedev);
+
+	error = mixdev_add_device(mousedev);
+	if (error) {
+		mousedev_destroy(mousedev);
+		return error;
+	}
+
+	return 0;
+}
+
+static void mousedev_disconnect(struct input_handle *handle)
+{
+	struct mousedev *mousedev = handle->private;
+
+	mixdev_remove_device(mousedev);
+	mousedev_destroy(mousedev);
+}
+
+static const struct input_device_id mousedev_ids[] = {
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+				INPUT_DEVICE_ID_MATCH_KEYBIT |
+				INPUT_DEVICE_ID_MATCH_RELBIT,
+		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) },
+		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
+		.relbit = { BIT_MASK(REL_X) | BIT_MASK(REL_Y) },
+	},	/* A mouse like device, at least one button,
+		   two relative axes */
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+				INPUT_DEVICE_ID_MATCH_RELBIT,
+		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) },
+		.relbit = { BIT_MASK(REL_WHEEL) },
+	},	/* A separate scrollwheel */
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+				INPUT_DEVICE_ID_MATCH_KEYBIT |
+				INPUT_DEVICE_ID_MATCH_ABSBIT,
+		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
+		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
+		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) },
+	},	/* A tablet like device, at least touch detection,
+		   two absolute axes */
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+				INPUT_DEVICE_ID_MATCH_KEYBIT |
+				INPUT_DEVICE_ID_MATCH_ABSBIT,
+		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
+		.keybit = { [BIT_WORD(BTN_TOOL_FINGER)] =
+				BIT_MASK(BTN_TOOL_FINGER) },
+		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
+				BIT_MASK(ABS_PRESSURE) |
+				BIT_MASK(ABS_TOOL_WIDTH) },
+	},	/* A touchpad */
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+			INPUT_DEVICE_ID_MATCH_KEYBIT |
+			INPUT_DEVICE_ID_MATCH_ABSBIT,
+		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
+		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
+		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) },
+	},	/* Mouse-like device with absolute X and Y but ordinary
+		   clicks, like hp ILO2 High Performance mouse */
+
+	{ },	/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(input, mousedev_ids);
+
+static struct input_handler mousedev_handler = {
+	.event		= mousedev_event,
+	.connect	= mousedev_connect,
+	.disconnect	= mousedev_disconnect,
+	.legacy_minors	= true,
+	.minor		= MOUSEDEV_MINOR_BASE,
+	.name		= "mousedev",
+	.id_table	= mousedev_ids,
+};
+
+#ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
+#include <linux/miscdevice.h>
+
+static struct miscdevice psaux_mouse = {
+	.minor	= PSMOUSE_MINOR,
+	.name	= "psaux",
+	.fops	= &mousedev_fops,
+};
+
+static bool psaux_registered;
+
+static void __init mousedev_psaux_register(void)
+{
+	int error;
+
+	error = misc_register(&psaux_mouse);
+	if (error)
+		pr_warn("could not register psaux device, error: %d\n",
+			   error);
+	else
+		psaux_registered = true;
+}
+
+static void __exit mousedev_psaux_unregister(void)
+{
+	if (psaux_registered)
+		misc_deregister(&psaux_mouse);
+}
+#else
+static inline void mousedev_psaux_register(void) { }
+static inline void mousedev_psaux_unregister(void) { }
+#endif
+
+static int __init mousedev_init(void)
+{
+	int error;
+
+	mousedev_mix = mousedev_create(NULL, &mousedev_handler, true);
+	if (IS_ERR(mousedev_mix))
+		return PTR_ERR(mousedev_mix);
+
+	error = input_register_handler(&mousedev_handler);
+	if (error) {
+		mousedev_destroy(mousedev_mix);
+		return error;
+	}
+
+	mousedev_psaux_register();
+
+	pr_info("PS/2 mouse device common for all mice\n");
+
+	return 0;
+}
+
+static void __exit mousedev_exit(void)
+{
+	mousedev_psaux_unregister();
+	input_unregister_handler(&mousedev_handler);
+	mousedev_destroy(mousedev_mix);
+}
+
+module_init(mousedev_init);
+module_exit(mousedev_exit);