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

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

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

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

 - Fix use-after-free for same named historgrams

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

   Free the duplicate variables along with the duplicated histogram
   data.

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

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

 - Fix race between reading trace_pipe and updating subbuffer size

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

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

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

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

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

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

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

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

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

 - Fix retry exhaustion in simple ring buffer reader swap

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

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

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

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

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

1 files changed, 833 insertions, 0 deletions

diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
new file mode 100644
index 000000000..cdbb1023a
--- /dev/null
+++ b/drivers/acpi/button.c
@@ -0,0 +1,833 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  button.c - ACPI Button Driver
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ */
+
+#define pr_fmt(fmt) "ACPI: button: " fmt
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/dmi.h>
+#include <linux/platform_device.h>
+#include <acpi/button.h>
+
+#define ACPI_BUTTON_CLASS		"button"
+#define ACPI_BUTTON_FILE_STATE		"state"
+#define ACPI_BUTTON_TYPE_UNKNOWN	0x00
+#define ACPI_BUTTON_NOTIFY_WAKE		0x02
+#define ACPI_BUTTON_NOTIFY_STATUS	0x80
+
+#define ACPI_BUTTON_CLASS_POWER		"button/power"
+#define ACPI_BUTTON_DEVICE_NAME_POWER	"Power Button"
+#define ACPI_BUTTON_TYPE_POWER		0x01
+
+#define ACPI_BUTTON_CLASS_SLEEP		"button/sleep"
+#define ACPI_BUTTON_DEVICE_NAME_SLEEP	"Sleep Button"
+#define ACPI_BUTTON_TYPE_SLEEP		0x03
+
+#define ACPI_BUTTON_CLASS_LID		"button/lid"
+#define ACPI_BUTTON_SUBCLASS_LID	"lid"
+#define ACPI_BUTTON_DEVICE_NAME_LID	"Lid Switch"
+#define ACPI_BUTTON_TYPE_LID		0x05
+
+enum {
+	ACPI_BUTTON_LID_INIT_IGNORE,
+	ACPI_BUTTON_LID_INIT_OPEN,
+	ACPI_BUTTON_LID_INIT_METHOD,
+	ACPI_BUTTON_LID_INIT_DISABLED,
+};
+
+static const char * const lid_init_state_str[] = {
+	[ACPI_BUTTON_LID_INIT_IGNORE]		= "ignore",
+	[ACPI_BUTTON_LID_INIT_OPEN]		= "open",
+	[ACPI_BUTTON_LID_INIT_METHOD]		= "method",
+	[ACPI_BUTTON_LID_INIT_DISABLED]		= "disabled",
+};
+
+MODULE_AUTHOR("Paul Diefenbaugh");
+MODULE_DESCRIPTION("ACPI Button Driver");
+MODULE_LICENSE("GPL");
+
+static const struct acpi_device_id button_device_ids[] = {
+	{ACPI_BUTTON_HID_LID, ACPI_BUTTON_TYPE_LID},
+	{ACPI_BUTTON_HID_SLEEP, ACPI_BUTTON_TYPE_SLEEP},
+	{ACPI_BUTTON_HID_SLEEPF, ACPI_BUTTON_TYPE_SLEEP},
+	{ACPI_BUTTON_HID_POWER, ACPI_BUTTON_TYPE_POWER},
+	{ACPI_BUTTON_HID_POWERF, ACPI_BUTTON_TYPE_POWER},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, button_device_ids);
+
+/* Please keep this list sorted alphabetically by vendor and model */
+static const struct dmi_system_id dmi_lid_quirks[] = {
+	{
+		/* GP-electronic T701, _LID method points to a floating GPIO */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
+			DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
+	},
+	{
+		/* Nextbook Ares 8A tablet, _LID device always reports lid closed */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CherryTrail"),
+			DMI_MATCH(DMI_BIOS_VERSION, "M882"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
+	},
+	{
+		/*
+		 * Lenovo Yoga 9 14ITL5, initial notification of the LID device
+		 * never happens.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "82BG"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Medion Akoya E2215T, notification of the LID device only
+		 * happens on close, not on open and _LID always returns closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "E2215T"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Medion Akoya E2228T, notification of the LID device only
+		 * happens on close, not on open and _LID always returns closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "E2228T"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Razer Blade Stealth 13 late 2019, notification of the LID device
+		 * only happens on close, not on open and _LID always returns closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Razer Blade Stealth 13 Late 2019"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Razer Blade Pro 17 early 2020, notification of the LID device
+		 * only happens on close, not on open and _LID keeps returning closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Blade Pro 17 (Early 2020) - RZ09-0329"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{
+		/*
+		 * Samsung galaxybook2 ,initial _LID device notification returns
+		 * lid closed.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "750XED"),
+		},
+		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+	},
+	{}
+};
+
+static int acpi_button_probe(struct platform_device *pdev);
+static void acpi_button_remove(struct platform_device *pdev);
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_button_suspend(struct device *dev);
+static int acpi_button_resume(struct device *dev);
+#else
+#define acpi_button_suspend NULL
+#define acpi_button_resume NULL
+#endif
+static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
+
+static struct platform_driver acpi_button_driver = {
+	.probe = acpi_button_probe,
+	.remove = acpi_button_remove,
+	.driver = {
+		.name = "acpi-button",
+		.acpi_match_table = button_device_ids,
+		.pm = &acpi_button_pm,
+	},
+};
+
+struct acpi_button {
+	struct acpi_device *adev;
+	struct device *dev;		/* physical button device */
+	unsigned int type;
+	struct input_dev *input;
+	const char *class;		/* for netlink messages */
+	char phys[32];			/* for input device */
+	unsigned long pushed;
+	bool last_state;
+	ktime_t last_time;
+	bool suspended;
+	bool lid_state_initialized;
+	bool gpe_enabled;
+};
+
+static long lid_init_state = -1;
+
+static unsigned long lid_report_interval __read_mostly = 500;
+module_param(lid_report_interval, ulong, 0644);
+MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
+
+/* FS Interface (/proc) */
+static struct proc_dir_entry *acpi_button_dir;
+static struct proc_dir_entry *acpi_lid_dir;
+
+static int acpi_lid_evaluate_state(acpi_handle lid_handle)
+{
+	unsigned long long lid_state;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(lid_handle, "_LID", NULL, &lid_state);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return !!lid_state;
+}
+
+static void acpi_lid_notify_state(struct acpi_button *button, bool state)
+{
+	struct acpi_device *device = button->adev;
+	ktime_t next_report;
+	bool do_update;
+
+	/*
+	 * In lid_init_state=ignore mode, if user opens/closes lid
+	 * frequently with "open" missing, and "last_time" is also updated
+	 * frequently, "close" cannot be delivered to the userspace.
+	 * So "last_time" is only updated after a timeout or an actual
+	 * switch.
+	 */
+	do_update = lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
+			button->last_state != state;
+	next_report = ktime_add(button->last_time,
+				ms_to_ktime(lid_report_interval));
+	if (button->last_state == state &&
+	    ktime_after(ktime_get(), next_report)) {
+		/* Complain about the buggy firmware. */
+		pr_warn_once(FW_BUG "Unexpected lid state reported by firmware\n");
+
+		/*
+		 * Send the unreliable complement switch event:
+		 *
+		 * On most platforms, the lid device is reliable. However
+		 * there are exceptions:
+		 * 1. Platforms returning initial lid state as "close" by
+		 *    default after booting/resuming:
+		 *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
+		 *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
+		 * 2. Platforms never reporting "open" events:
+		 *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
+		 * On these buggy platforms, the usage model of the ACPI
+		 * lid device actually is:
+		 * 1. The initial returning value of _LID may not be
+		 *    reliable.
+		 * 2. The open event may not be reliable.
+		 * 3. The close event is reliable.
+		 *
+		 * But SW_LID is typed as input switch event, the input
+		 * layer checks if the event is redundant. Hence if the
+		 * state is not switched, the userspace cannot see this
+		 * platform triggered reliable event. By inserting a
+		 * complement switch event, it then is guaranteed that the
+		 * platform triggered reliable one can always be seen by
+		 * the userspace.
+		 */
+		if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
+			do_update = true;
+			/*
+			 * Do generate complement switch event for "close"
+			 * as "close" is reliable and wrong "open" won't
+			 * trigger unexpected behaviors.
+			 * Do not generate complement switch event for
+			 * "open" as "open" is not reliable and wrong
+			 * "close" will trigger unexpected behaviors.
+			 */
+			if (!state) {
+				input_report_switch(button->input,
+						    SW_LID, state);
+				input_sync(button->input);
+			}
+		}
+	}
+	/* Send the platform triggered reliable event */
+	if (do_update) {
+		acpi_handle_debug(device->handle, "ACPI LID %s\n",
+				  state ? "open" : "closed");
+		input_report_switch(button->input, SW_LID, !state);
+		input_sync(button->input);
+		button->last_state = state;
+		button->last_time = ktime_get();
+	}
+}
+
+static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
+						     void *offset)
+{
+	struct acpi_button *button = seq->private;
+	int state;
+
+	state = acpi_lid_evaluate_state(button->adev->handle);
+	seq_printf(seq, "state:      %s\n",
+		   state < 0 ? "unsupported" : (state ? "open" : "closed"));
+	return 0;
+}
+
+static int acpi_lid_add_fs(struct acpi_button *button)
+{
+	struct acpi_device *device = button->adev;
+	struct proc_dir_entry *entry = NULL;
+
+	if (acpi_button_dir || acpi_lid_dir) {
+		pr_info("More than one Lid device found!\n");
+		return -EEXIST;
+	}
+
+	/* create /proc/acpi/button */
+	acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
+	if (!acpi_button_dir)
+		return -ENODEV;
+
+	/* create /proc/acpi/button/lid */
+	acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+	if (!acpi_lid_dir)
+		goto remove_button_dir;
+
+	/* create /proc/acpi/button/lid/LID/ */
+	acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
+	if (!acpi_device_dir(device))
+		goto remove_lid_dir;
+
+	/* create /proc/acpi/button/lid/LID/state */
+	entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
+			acpi_device_dir(device), acpi_button_state_seq_show,
+			button);
+	if (!entry)
+		goto remove_dev_dir;
+
+	return 0;
+
+remove_dev_dir:
+	remove_proc_entry(acpi_device_bid(device), acpi_lid_dir);
+	acpi_device_dir(device) = NULL;
+remove_lid_dir:
+	remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+	acpi_lid_dir = NULL;
+remove_button_dir:
+	remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
+	acpi_button_dir = NULL;
+	return -ENODEV;
+}
+
+static void acpi_lid_remove_fs(void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *device = button->adev;
+
+	remove_proc_entry(ACPI_BUTTON_FILE_STATE,
+			  acpi_device_dir(device));
+	remove_proc_entry(acpi_device_bid(device),
+			  acpi_lid_dir);
+	acpi_device_dir(device) = NULL;
+	remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+	acpi_lid_dir = NULL;
+	remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
+	acpi_button_dir = NULL;
+}
+
+static int devm_acpi_lid_add_fs(struct device *dev, struct acpi_button *button)
+{
+	int ret;
+
+	ret = acpi_lid_add_fs(button);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, acpi_lid_remove_fs, button);
+}
+
+static acpi_handle saved_lid_handle;
+static DEFINE_MUTEX(acpi_lid_lock);
+
+static void acpi_lid_save(struct acpi_device *adev)
+{
+	guard(mutex)(&acpi_lid_lock);
+
+	saved_lid_handle = adev->handle;
+}
+
+static void acpi_lid_forget(struct acpi_device *adev)
+{
+	guard(mutex)(&acpi_lid_lock);
+
+	if (saved_lid_handle == adev->handle)
+		saved_lid_handle = NULL;
+}
+
+/* Driver Interface */
+int acpi_lid_open(void)
+{
+	guard(mutex)(&acpi_lid_lock);
+
+	if (!saved_lid_handle)
+		return -ENODEV;
+
+	return acpi_lid_evaluate_state(saved_lid_handle);
+}
+EXPORT_SYMBOL(acpi_lid_open);
+
+static void acpi_lid_update_state(struct acpi_button *button, bool signal_wakeup)
+{
+	int state;
+
+	state = acpi_lid_evaluate_state(button->adev->handle);
+	if (state < 0)
+		return;
+
+	if (state && signal_wakeup)
+		acpi_pm_wakeup_event(button->dev);
+
+	acpi_lid_notify_state(button, state);
+}
+
+static void acpi_lid_initialize_state(struct acpi_button *button)
+{
+	switch (lid_init_state) {
+	case ACPI_BUTTON_LID_INIT_OPEN:
+		acpi_lid_notify_state(button, true);
+		break;
+	case ACPI_BUTTON_LID_INIT_METHOD:
+		acpi_lid_update_state(button, false);
+		break;
+	case ACPI_BUTTON_LID_INIT_IGNORE:
+	default:
+		break;
+	}
+
+	button->lid_state_initialized = true;
+}
+
+static void acpi_lid_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *device = button->adev;
+
+	if (event != ACPI_BUTTON_NOTIFY_STATUS) {
+		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
+				  event);
+		return;
+	}
+
+	if (!button->lid_state_initialized)
+		return;
+
+	acpi_lid_update_state(button, true);
+}
+
+static void acpi_button_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *device = button->adev;
+	struct input_dev *input;
+	int keycode;
+
+	switch (event) {
+	case ACPI_BUTTON_NOTIFY_STATUS:
+		break;
+	case ACPI_BUTTON_NOTIFY_WAKE:
+		break;
+	default:
+		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
+				  event);
+		return;
+	}
+
+	acpi_pm_wakeup_event(button->dev);
+
+	if (button->suspended || event == ACPI_BUTTON_NOTIFY_WAKE)
+		return;
+
+	input = button->input;
+	keycode = test_bit(KEY_SLEEP, input->keybit) ? KEY_SLEEP : KEY_POWER;
+
+	input_report_key(input, keycode, 1);
+	input_sync(input);
+	input_report_key(input, keycode, 0);
+	input_sync(input);
+
+	acpi_bus_generate_netlink_event(button->class, dev_name(&device->dev),
+					event, ++button->pushed);
+}
+
+static void acpi_button_notify_run(void *data)
+{
+	acpi_button_notify(NULL, ACPI_BUTTON_NOTIFY_STATUS, data);
+}
+
+static u32 acpi_button_event(void *data)
+{
+	acpi_os_execute(OSL_NOTIFY_HANDLER, acpi_button_notify_run, data);
+	return ACPI_INTERRUPT_HANDLED;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_button_suspend(struct device *dev)
+{
+	struct acpi_button *button = dev_get_drvdata(dev);
+
+	button->suspended = true;
+	return 0;
+}
+
+static int acpi_button_resume(struct device *dev)
+{
+	struct acpi_button *button = dev_get_drvdata(dev);
+	struct input_dev *input;
+
+	button->suspended = false;
+	if (button->type == ACPI_BUTTON_TYPE_LID) {
+		button->last_state = !!acpi_lid_evaluate_state(ACPI_HANDLE(dev));
+		button->last_time = ktime_get();
+		acpi_lid_initialize_state(button);
+	}
+
+	if (button->type == ACPI_BUTTON_TYPE_POWER) {
+		input = button->input;
+		input_report_key(input, KEY_WAKEUP, 1);
+		input_sync(input);
+		input_report_key(input, KEY_WAKEUP, 0);
+		input_sync(input);
+	}
+	return 0;
+}
+#endif
+
+static int acpi_lid_input_open(struct input_dev *input)
+{
+	struct acpi_button *button = input_get_drvdata(input);
+
+	button->last_state = !!acpi_lid_evaluate_state(button->adev->handle);
+	button->last_time = ktime_get();
+	acpi_lid_initialize_state(button);
+
+	return 0;
+}
+
+static acpi_notify_handler acpi_button_notify_handler(struct acpi_button *button)
+{
+	if (button->type == ACPI_BUTTON_TYPE_LID)
+		return acpi_lid_notify;
+
+	return acpi_button_notify;
+}
+
+static void acpi_button_wakeup_cleanup(void *data)
+{
+	device_init_wakeup(data, false);
+}
+
+static int devm_acpi_button_init_wakeup(struct device *dev)
+{
+	device_init_wakeup(dev, true);
+	return devm_add_action_or_reset(dev, acpi_button_wakeup_cleanup, dev);
+}
+
+static void acpi_button_remove_event_handler(void *data)
+{
+	struct acpi_button *button = data;
+	struct acpi_device *adev = button->adev;
+
+	switch (adev->device_type) {
+	case ACPI_BUS_TYPE_POWER_BUTTON:
+		acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
+						acpi_button_event);
+		break;
+
+	case ACPI_BUS_TYPE_SLEEP_BUTTON:
+		acpi_remove_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
+						acpi_button_event);
+		break;
+
+	default:
+		if (button->gpe_enabled) {
+			dev_dbg(button->dev, "Disabling ACPI GPE%02llx\n",
+				adev->wakeup.gpe_number);
+			acpi_disable_gpe(adev->wakeup.gpe_device,
+					 adev->wakeup.gpe_number);
+		}
+		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
+					   acpi_button_notify_handler(button));
+		break;
+	}
+	acpi_os_wait_events_complete();
+}
+
+static int acpi_button_add_fixed_event_handler(u32 event,
+					       struct acpi_button *button)
+{
+	acpi_status status;
+
+	status = acpi_install_fixed_event_handler(event, acpi_button_event, button);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return 0;
+}
+
+static int acpi_button_add_event_handler(struct acpi_button *button)
+{
+	struct acpi_device *adev = button->adev;
+	acpi_status status;
+
+	if (adev->device_type == ACPI_BUS_TYPE_POWER_BUTTON)
+		return acpi_button_add_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
+							   button);
+
+	if (adev->device_type == ACPI_BUS_TYPE_SLEEP_BUTTON)
+		return acpi_button_add_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
+							   button);
+
+	status = acpi_install_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
+					     acpi_button_notify_handler(button),
+					     button);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	if (!adev->wakeup.flags.valid)
+		return 0;
+
+	/*
+	 * If the wakeup GPE has a handler method, enable it in case it is also
+	 * used for signaling runtime events.
+	 */
+	status = acpi_enable_gpe_cond(adev->wakeup.gpe_device,
+				      adev->wakeup.gpe_number,
+				      ACPI_GPE_DISPATCH_METHOD);
+	button->gpe_enabled = ACPI_SUCCESS(status);
+	if (button->gpe_enabled)
+		dev_dbg(button->dev, "Enabled ACPI GPE%02llx\n",
+			adev->wakeup.gpe_number);
+
+	return 0;
+}
+
+static int devm_acpi_button_add_event_handler(struct device *dev,
+					      struct acpi_button *button)
+{
+	int ret;
+
+	ret = acpi_button_add_event_handler(button);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, acpi_button_remove_event_handler,
+					button);
+}
+
+static int acpi_button_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct acpi_device *device = ACPI_COMPANION(dev);
+	const struct acpi_device_id *id;
+	struct acpi_button *button;
+	struct input_dev *input;
+	u8 button_type;
+	int error = 0;
+
+	id = acpi_match_acpi_device(button_device_ids, device);
+	if (!id || strcmp(acpi_device_hid(device), id->id))
+		return dev_err_probe(dev, -ENODEV, "Unsupported device\n");
+
+	button_type = id->driver_data;
+	if (button_type == ACPI_BUTTON_TYPE_LID &&
+	    lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
+		return -ENODEV;
+
+	button = devm_kzalloc(dev, sizeof(*button), GFP_KERNEL);
+	if (!button)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, button);
+
+	button->dev = dev;
+	button->adev = device;
+	input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	button->input = input;
+	button->type = button_type;
+
+	switch (button_type) {
+	case ACPI_BUTTON_TYPE_LID:
+		button->class = ACPI_BUTTON_CLASS_LID;
+
+		input->name = ACPI_BUTTON_DEVICE_NAME_LID;
+		input_set_capability(input, EV_SW, SW_LID);
+		input->open = acpi_lid_input_open;
+
+		error = devm_acpi_lid_add_fs(dev, button);
+		if (error)
+			return error;
+
+		break;
+
+	case ACPI_BUTTON_TYPE_POWER:
+		button->class = ACPI_BUTTON_CLASS_POWER;
+
+		input->name = ACPI_BUTTON_DEVICE_NAME_POWER;
+		input_set_capability(input, EV_KEY, KEY_POWER);
+		input_set_capability(input, EV_KEY, KEY_WAKEUP);
+		break;
+
+	case ACPI_BUTTON_TYPE_SLEEP:
+		button->class = ACPI_BUTTON_CLASS_SLEEP;
+
+		input->name = ACPI_BUTTON_DEVICE_NAME_SLEEP;
+		input_set_capability(input, EV_KEY, KEY_SLEEP);
+		break;
+
+	default:
+		return dev_err_probe(dev, -ENODEV, "Unrecognized button type\n");
+	}
+
+	snprintf(button->phys, sizeof(button->phys), "%s/button/input0",
+		 acpi_device_hid(device));
+
+	input->phys = button->phys;
+	input->id.bustype = BUS_HOST;
+	input->id.product = button_type;
+
+	input_set_drvdata(input, button);
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	error = devm_acpi_button_init_wakeup(dev);
+	if (error)
+		return error;
+
+	error = devm_acpi_button_add_event_handler(dev, button);
+	if (error)
+		return error;
+
+	if (button_type == ACPI_BUTTON_TYPE_LID) {
+		/*
+		 * This assumes there's only one lid device, or if there are
+		 * more we only care about the last one...
+		 */
+		acpi_lid_save(device);
+	}
+
+	pr_info("%s [%s]\n", input->name, acpi_device_bid(device));
+
+	return 0;
+}
+
+static void acpi_button_remove(struct platform_device *pdev)
+{
+	struct acpi_button *button = platform_get_drvdata(pdev);
+
+	if (button->type == ACPI_BUTTON_TYPE_LID)
+		acpi_lid_forget(button->adev);
+}
+
+static int param_set_lid_init_state(const char *val,
+				    const struct kernel_param *kp)
+{
+	int i;
+
+	i = sysfs_match_string(lid_init_state_str, val);
+	if (i < 0)
+		return i;
+
+	lid_init_state = i;
+	pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
+	return 0;
+}
+
+static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
+{
+	int i, c = 0;
+
+	for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
+		if (i == lid_init_state)
+			c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
+		else
+			c += sprintf(buf + c, "%s ", lid_init_state_str[i]);
+
+	buf[c - 1] = '\n'; /* Replace the final space with a newline */
+
+	return c;
+}
+
+module_param_call(lid_init_state,
+		  param_set_lid_init_state, param_get_lid_init_state,
+		  NULL, 0644);
+MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
+
+static int __init acpi_button_init(void)
+{
+	const struct dmi_system_id *dmi_id;
+
+	if (lid_init_state == -1) {
+		dmi_id = dmi_first_match(dmi_lid_quirks);
+		if (dmi_id)
+			lid_init_state = (long)dmi_id->driver_data;
+		else
+			lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
+	}
+
+	/*
+	 * Modules such as nouveau.ko and i915.ko have a link time dependency
+	 * on acpi_lid_open(), and would therefore not be loadable on ACPI
+	 * capable kernels booted in non-ACPI mode if the return value of
+	 * platform_driver_register() is returned from here with ACPI disabled
+	 * when this driver is built as a module.
+	 */
+	if (acpi_disabled)
+		return 0;
+
+	return platform_driver_register(&acpi_button_driver);
+}
+
+static void __exit acpi_button_exit(void)
+{
+	if (!acpi_disabled)
+		platform_driver_unregister(&acpi_button_driver);
+}
+
+module_init(acpi_button_init);
+module_exit(acpi_button_exit);